This program aims to attract early career scientists with novel ideas into melanoma research, thereby recruiting and supporting the next generation of melanoma researchers. Young Investigators are scientists within four years of their first academic faculty appointment. A mentorship commitment from a senior investigator is required.
Expanding immune-surveillance and immunotherapy of melanoma
Brigham and Women’s Hospital-MRA Young Investigator Award
Niroshana Anandasabapathy, MD PhD, Brigham and Women's Hospital, Inc. Mentors: F. Stephen Hodi, M.D., Dana-Farber Cancer Institute and Thomas Kupper, M.D., Brigham and Women’s Hospital
Recent major advances have been made in helping the immune system to fight melanoma through T cell immunity. Our laboratory studies the Dendritic cell (DC). This key immune cell trains T cells to respond to tumors, viruses and vaccine and is central to long-term protective immunity. DC monitor and survey the skin closely as well and are present in normal moles as well as in skin cancers, including melanoma. However DC that could help to fight melanoma exist in low abundance creating an obstacle to successful translational efforts. This application will improve how the immune system recognizes and fights melanoma by improving how DC find and present tumor proteins and their numbers and function. We will determine mechanisms by which expanding key DC in human subjects can improve immunity. We will also investigate the pathways and mechanisms by which the DC fail to see primary melanoma and metastatic disease in mouse and humans. Lastly we will identify new pathways by which we can train these immune cells to better present tumor proteins to T cells and create long-term protective immune memory, breaking the bodies tolerance to melanoma. As part of this application we will also understand whether the program of DC can be used to predict progression from moles to skin cancer in people. This work will be closely curated by a refined mentorship. Dr. Thomas Kupper is an expert in the generation of long-term protective immunity to vaccines through the skin. Drs. Steve Hodi is an expert in melanoma immunotherapy and clinical trials for melanoma and Dr. Yvonne Saenger is a collaborator who has recently identified important genetic markers for melanoma progression.
Immune and tumor-intrinsic roles of the Tim-3/Galectin-9 axis in melanoma
Merck-MRA Young Investigator Award
Steven Barthel, Ph.D., Brigham and Women’s Hospital Mentor: Thomas Kupper, M.D., Brigham and Women’s Hospital
Melanoma occurs when healthy skin cells, melanocytes, become abnormal and grow uncontrollably. Our immune system usually destroys abnormal melanocytes before they become cancerous. Unfortunately, melanomas escape destruction by suppressing our immune system through activation of an inhibitor called Tim-3 found on immune cells. Since blocking of Tim-3 boosts immune-killing of melanomas, therapies targeting Tim-3 are expected to enter human melanoma trials to treat patients. Since these promising Tim-3 drugs have not yet been tested in humans, and since the manner in which they kill melanoma is unclear, unanswered questions on Tim-3 drug safety, specificity, potency, and optimization exist. Further, while Tim-3 therapies were believed to target only immune cells as noted above, we have newly identified Tim-3 DIRECTLY on melanoma cells and uncovered therapeutically exciting, unexpected roles of melanoma-Tim-3 that could lead to rapid progression to clinical testing.
This proposal therapeutically explores and develops melanoma-Tim-3 as a new biomarker for predicting/staging melanoma and as a novel target for innovative treatments against melanoma. As our data reveals that Tim-3 on melanoma cells powerfully influences melanoma progression, this research will lay the groundwork for new therapies targeting melanoma-Tim-3. Results also raise caution in administering anticipated Tim-3 drugs to human cancer patients given the possibility of these drugs to unexpectedly impact melanoma-Tim-3 function. This research will impact the diagnosis and treatment of melanoma and potentially other cancers, promote multidisciplinary, collaborative investigation into a new pathway of cancer, lead to diverse and expansive research projects, and catalyze rapid and long-term therapeutic development targeting melanoma-Tim-3.
In Situ Tumor Microenvironnment Profiles for Immunotherapy Responders
Yale-MRA Young Investigator Award
Kim Blenman, PhD, Yale University Mentor: Marcus Bosenberg, MD, PhD, Yale University
There are a significant amount of immunotherapeutic agents approved for melanoma. The efficacy results from anti-CTLA-4 (Ipilimumab) monotherapy, anti-PD-1 (Nivolumab, Pembrolizumab) monotherapy, and combination of two immunotherapies (Ipilimumab + Nivolumab) are encouraging. The ability of these immunotherapeutic agents to produce not only long-term responses but complete responses will depend heavily on the microenvironment in which the cancer cells exist. Understanding how these therapeutic agents affect the cells in their intact microenvironments will help us to select those patients that would benefit the most from these treatments. The information will also help us to develop the best approaches to combining these immunotherapeutic agents to maximize their effectiveness and reduce/eliminate adverse events. We hypothesize that unique tumor microenvironment profiles can be used to determine responders to Ipilimumab, anti-PD-1, and combination therapy. To address this we will generate tumor microenvironment profiles using SQISBA (multiplexed staining, quantitative imaging, and software-based analysis). SQISBA allows assessment of cell distributions, spatial relationships, and target antigen intensities. This platform method is transformative because it allows quantitative assessment of cell functions and interactions at the global level as well as the single cell level. For our proposal we will 1) investigate the biology of the melanoma tumor microenvironment to establish a method to quantitatively assess cell population distributions and spatial relationships in patients pre- Ipilimumab and anti-PD-1 (Nivolumab; Pembrolizumab; Pidilizumab) treatment, and 2) predict responders to mono- and combination Ipilimumab and Nivolumab therapy by quantitative analysis of key cells and targets mediating the therapeutic response pre-treatment. We plan to incorporate the unique insights uncovered from this study into future clinical treatments of mono- and combination therapy.
Boosting migration of tumor-specific T cells to improve immunotherapy
UCSD-MRA Young Investigator Award
Joseph Cantor, Ph.D., The Regents of the University of California, San Diego Mentor: Mark Ginsberg, MD, University of California, San Diego
Infusion of modified T cells is an exciting new immunotherapy for melanoma, but is hampered by poor migration of T cells to the tumor site. We have identified a novel process, termed integrin transregulation, that may overcome this barrier and allow efficient migration of injected T cells to tumors for more effective tumor killing. We propose to test this approach in mice and in human T cells to determine if integrin transregulation can improve tumor homing of injected melanoma-specific T cells. If successful, this strategy will open the door for more successful modified T cell immunotherapy for melanoma.
Targeted shRNA screen to enhance CD8 T cell activity and memory in melanoma
Anna-Maria and Stephen Kellen-MRA Young Investigator Award
Stephanie Dougan, Ph.D., Dana-Farber Cancer Institute Mentor: Kai Wucherpfennig, M.D., Ph.D., Dana-Farber Cancer Institute
The immune system is a powerful resource for fighting tumors. Cytotoxic T cells can distinguish tumor cells from normal tissue with pinpoint precision, and they can migrate to seek out and destroy tumor cells wherever and whenever they arise. For the lucky patients who develop memory cytotoxic T cells, these cells remain constantly on surveillance, preventing relapse, and providing long-term cures. Immune-based therapies have been used successfully in melanoma for which the FDA approved use of Yervoy and Keytruda, drugs that block immune inhibitory pathways and activate cytotoxic T cells. However, not all patients respond to immune-based therapies, and not all responders experience long-term cures. Here we use new mouse models to evaluate potential genes involved in cytotoxic T cell responses. We aim to find genes that, when rendered inactive, lead to robust cytotoxic T cell responses and formation of long-term memory cells. We will evaluate synergy of these gene inactivations with currently approved immune-based therapies. Our overall goal is to identify new drug targets for use in combination therapies aimed at augmenting cytotoxic T cell responses and memory formation.
Defining Novel Mechanisms of Genome Instability in Human Melanoma
Jackie King-MRA Young Investigator Award
Neil Ganem, Ph.D., Boston University Medical Campus Mentor: Douglas Faller, M.D., Ph.D., Boston University Medical Campus
Melanoma is a malignant neoplasm arising from melanocytes, which are pigment-producing cells in the skin. It is diagnosed in over 120,000 Americans each year, and is the most common cancer in young adults between the ages of 25 and 29. As such, melanoma represents a substantial public health burden, and understanding the molecular principles underlying its pathogenesis is crucial for the development of effective preventative and therapeutic strategies. One of the hallmarks of melanoma cancer cells is that they are highly aneuploid, meaning that they possess an abnormal number of chromosomes. Though already abnormal, many aneuploid melanoma cells continue to shuffle their chromosome content, often gaining and losing chromosomes with each cell division. This phenomenon is termed chromosome instability (CIN). CIN is known to promote tumor initiation, progression, and relapse following targeted therapeutics. Consequently, CIN confers poor clinical prognosis. Understanding the mechanisms by which melanoma cells become CIN therefore remains of paramount importance. Our preliminary data suggest that mutations in a gene called BRAF, which occur in >80% of all melanomas, may be responsible for the unequal segregation of chromosomes during cell division. One focus of this proposal is to mechanistically define the basis for this affect. In addition, our preliminary data suggest that mutations in BRAF may also cause chromosome instability by promoting the rupture of a cellular structure called the nucleus, which normally acts to protect DNA. Thus, a second focus of this proposal is to determine how BRAF mutations promote nuclear rupture and DNA damage. Collectively, this work has the potential to reveal novel therapeutic avenues that selectively kill abnormal, chromosomally unstable melanoma cells while sparing the normal cells from which they originated.
Melanoma-Targeted T cells from Pluripotent Stem Cells for Immunotherapy
Leveraged Finance Fights Melanoma-MRA Young Investigator Award
Fumito Ito, M.D., Ph.D., University of Michigan Mentor: James Engel, Ph.D., University of Michigan
Metastasis, the spread of cancer cells to distant parts of the body, is the most common cause of death in patients with melanoma. Recently, adoptive cell therapy (ACT), a technique involving the expansion and infusion of a patient’s own tumor-specific immune cells (T lymphocytes), has emerged as one of the most effective treatments for patients with metastatic melanoma. One limitation of ACT that compromises its effectiveness is poor T cell survival following infusion into the patient. Preclinical and clinical studies show that young T cells are ideal for treating tumors because of their increased survival; however, it is difficult to generate large numbers of young T cells for ACT. Recently, scientists developed a new way to reprogram adult cells into embryonic-like cells, which are called induced pluripotent stem cells (iPSCs). Human iPSCs can be made to differentiate into a wide range of tissues, including T cells, which may be useful for medical treatments. However, it is unknown whether ACT using iPSC-derived T cells is safe and effective. The goal of this project is to use a novel preclinical model to determine whether iPSC-derived T cells can be safely and effectively used for treating melanoma. A major advantage of this method is that iPSCs can be stored and repeatedly used for generating an unlimited number of specific, tumor reactive T cells for ACT. Results from this research should provide the foundation for developing significantly improved anti-cancer treatment for patients with advanced and metastatic melanoma, and for future personalized cancer treatment.
Harnessing intra-lymph node controlled release to promote tumor immunity
MRA Young Investigator Award with Lead Support from the Damon Runyon Cancer Research Foundation
Christopher Jewell, Ph.D., University of Maryland-College Park Mentors: William Bentley, MD, University of Maryland-College Park and Anthony Sandler, Children’s Research Institute
Therapeutic cancer vaccines have the potential to transform cancer therapy by providing more potent and specific treatments. These vaccines involve arming immune cells against molecules that are overexpressed on cancer cells. To effectively combat tumors, vaccines must generate potent tumor-specific immune responses that are functional in the immunosuppressive tumor environment, and that are able to resist tumor regrowth during relapse. An increasingly important challenge for the vaccine field is design of vaccines that generate immune responses tailored to combat target diseases such as melanoma or other cancers. In contrast to broadly-acting drugs or chemotherapy, these designer vaccines could offer highly-specific, immune-based treatments. Establishing strong immunological memory cells specific for tumors has recently been described as a potential route to improve cancer vaccines. These cells are highly proliferative and can quickly expand a large population of tumor-targeting immune cells that could clear established tumors and protect against tumor re-growth. Unfortunately maintaining large populations of these immune memory cells is challenging because as the cells expand, they begin to lose their ability to proliferate and expand other cells. In this proposal we will combine direct lymph node delivery with biomaterial particles loaded with signals to expand immune cells and direct these cells to immune memory. Lymph nodes are the tissues that coordinate immune response and controlled delivery of cancer vaccine components in lymph nodes could provide a new way to control directly control how T cells develop and function during cancer vaccination. As a new therapy, cells induced by these vaccines could efficiently and selectively destroy tumors in melanoma or other cancers while offering reduced side effects.
Evaluating Heterogeneity in Melanoma using Circulating Tumor Cells
SkinCeuticals-MRA Young Investigator Award
Rajan Kulkarni, M.D., Ph.D., University of California, Los Angeles Mentor: Dino Di Carlo, Ph.D., University of California, Los Angeles
Metastatic melanoma can be caused by a variety of changes in the original cancer cells. Understanding this variability will be critical to predicting response to newer therapies. However, resistance has been reported to develop and understanding how this resistance occurs will be very important clinically in order to better predict which patients will have maximal response. In advanced melanoma, small quantities of cells break off from the tumor and travel through the blood. These cells, called circulating tumor cells (CTCs), are thought to contribute to progression and may be the source of cells that cause spread (metastasis) of the cancer. We have developed a new technology for isolating melanoma CTCs from blood, which we call Vortex Chip. These CTCs hold promise for exploring variability in melanoma because it is much easier to collect blood samples and study the collected cancer cells than to perform invasive biopsies every few weeks. The Vortex Chip will allow us to monitor response to different treatments by following CTC count before, during, and after chemotherapy. We will also isolate single CTCs and analyze these to determine if any new mutations have occurred. Simultaneously, we plan to sample the original primary and metastatic tumors from matched patients. We hope that these studies will allow us to better understand the variability in advanced melanoma and may help us to design improved treatments for future patients. It is hoped that we will obtain enough information from studying the CTCs and tumors, which can be directly utilized to better categorize how patients may respond to novel agents (specifically PD-1/PD-L1 inhibitors). We also hope that we will better understand how resistance may occur, and that we may possibly use such information to better direct treatment. This work will provide additional information about how the tumor evolves in response to treatment, which can be utilized to design more specific treatments to combat melanoma.
Novel approaches for immunotherapy against melanoma
Sotheby's-MRA Young Investigator Award
James Moon, Ph.D., University of Michigan Mentor: Alfred Chang, M.D., University of Michigan
Development of a successful immunotherapy against melanoma has been an elusive goal. One of the major hurdles in cancer immunotherapy is the limited capacity of the conventional vaccine adjuvants to elicit potent anti-tumoral T-cell responses. My long-range goal is to develop improved immunotherapies for melanoma patients. As the next step towards this goal, the objectives of this application are to construct a new vaccine delivery system that can generate potent anti-tumoral immune responses against metastatic and recurrent melanomas. Toward this goal, we recently developed a new vaccine nanoparticle system that can stably deliver antigens and immunostimulatory agents to dendritic cells (DCs), promote cross-presentation of antigens, and generate drastically enhanced T and B cell responses, compared with conventional adjuvants and DC-based vaccines. In this application, we propose to harness the tremendous potential of our vaccine strategy to achieve robust immune responses against metastatic and recurrent melanomas. At the completion of these studies, the proposed studies are expected to (1) provide fundamental information of how vaccine/adjuvant systems affect antigen delivery and presentation, (2) generate new knowledge on ways to achieve robust anti-tumoral T and B cell responses, (3) provide new insights into immunological targeting of melanoma cells, and (4) establish novel immunotherapeutic strategy against melanoma. Overall, the work proposed will explore a new paradigm for treatment of melanoma and have significant implications on cancer immunotherapy by addressing current limitations in cancer vaccines. We anticipate a tremendous amount of important new information will be forthcoming from these studies, advancing our fundamental understanding of roles that the adaptive immune system plays in tumor regression, metastasis, and recurrence.
Molecular determinants of NRAS oncogene dependency in melanoma
Anurag Singh, Ph.D., Boston University Medical Campus Mentor: Rhoda Alani, M.D., Boston University Medical Campus
NRAS mutant tumors. Furthermore, resistance to vemurafenib can rapidly develop in tumors due to a number of mechanisms, including the emergence of NRAS mutations. Unfortunately, effective NRAS blocking agents have yet to be identified and NRAS mutant tumors are considered “undruggable”. Our preliminary studies have shown that NRAS mutant cancer cell lines from human tumors exhibit varying molecular characteristics. We classified theses cell lines using global gene expression profiling into so-called “molecular subtypes”. Furthermore, cell lines in these major subtypes respond differently when the NRAS protein is blocked using RNA interference technology. Most of the cell lines respond by undergoing a form of cell death known as apoptosis, which occurs in tumors following treatment with anti- cancer agents. However, some cancer cell lines remain viable following the loss of mutant NRAS. Using the gene expression profiles that we have generated, we have isolated some candidate genes that we hypothesize will play a role in driving the growth and viability of NRAS mutant cancer cells in each of the subtypes that we identified. We will test this hypothesis in functional studies using RNA interference technology and pharmacological inhibitors. These studies will open avenues for the development of novel therapeutic strategies to treat aggressive NRAS mutant melanomas in the clinic.
Targeting Parallel Pathways to Overcome Treatment Resistance in Melanoma
Sotheby’s-MRA Young Investigator Award
Melissa Wilson, M.D., Ph.D., New York University School of Medicine Mentor: Anna Pavlick, D.O., New York University School of Medicine
Despite recent FDA approvals of immune therapy and targeted therapies for advanced stage melanoma, outcomes remain poor. Virtually all patients with tumors carrying an activating BRAF V600 mutation (50% of all melanomas) will develop resistance to BRAF inhibition in time. Overcoming resistance to BRAF inhibition to improve patient survival is the highest priority for targeted therapy research in advanced stage melanoma. ERBB3 has emerged as an important signaling molecule involved in acquired BRAF inhibitor resistance. We hypothesize that co-targeting ERBB3 and BRAF will enhance the clinical efficacy and extend progression free survival for patients receiving RAF and/or MEK inhibitors. The evaluation of biomarkers in pre- and post-treatment tumor samples will allow identification of a subset of patients who will benefit most from this combination of targeted therapies, resulting in individualization of patient treatment recommendations. Working with our collaborators, we will be able to perform clinically relevant translational research which will help to further stratify patients in the future for novel combination strategies and customized approaches in patient treatment and to overcome resistance to BRAF inhibition.
A novel mitochondrial inhibitor to overcome resistance to MAPK inhibition
Vashisht Yennu-Nanda, Ph.D., University of Texas M.D. Anderson Cancer Center Mentor: Michael Davies, M.D., Ph.D., University of Texas M.D. Anderson Cancer Center
Targeted therapies like Zelboraf® which inhibit the mutated BRAF protein in melanomas have dramatically improved the quality of life and survival in melanoma patients. However, these melanomas usually develop resistance to these treatments. In our laboratory, we have identified an unexpected mechanism of resistance to melanoma targeted therapies. We found that about half the melanomas we tested have very high mitochondrial respiration by utilizing a pathway called oxidative phosphorylation (“OxPhos”). OxPhos causes resistance by preventing the cells from dying when treated with BRAF or MEK inhibitors. In melanomas, OxPhos is activated by a protein factor called PGC1a, which is present in high levels in melanomas with high OxPhos. Additionally, we found that many melanoma cell lines and patients with low OxPhos/low PGC1a in their melanoma tumors initially respond to these treatments, but eventually develop resistance by increasing their OxPhos/PGC1a levels. Finally, we found that inhibiting OxPhos in these resistant melanomas restores their sensitivity to BRAF and MEK inhibitors. Based on these findings, we hypothesize that high OxPhos is a clinically significant marker of melanoma drug resistance, and an effective therapeutic target. Our research will test this hypothesis in two ways. First, we will study the expression of PGC1a and other genes associated with OxPhos in a large group of melanoma patients who have who have had different treatment outcomes. These will be compared against tumor features and outcomes of these patients, to better understand the clinical significance of OxPhos. Second, we will test a new experimental agent, IACS-10759, which is designed to inhibit mitochondrial OxPhos. This agent will be tested for its anti-cancer activity alone, and in combination with FDA-approved BRAF and MEK inhibitors in melanoma cell lines and in human tumors grown in mice. Positive findings may rapidly lead to new, personalized treatments for patients.
Harnessing Tim-3 Pathway Blockade for Melanoma Immunotherapy
Bristol-Myers Squibb-MRA Young Investigator Award
Ana Anderson, Ph.D., Brigham and Women's Hospital Mentor: Vijay K. Kuchroo, Ph.D., Brigham and Women's Hospital
Melanoma is a deadly cancer that accounts for the majority (80%) of deaths due to skin cancer. Recent therapies that harness the power of the immune system to fight cancer are providing new hope to patients suffering with melanoma. These therapies block inhibitory proteins such as CTLA-4 and PD-1 that are expressed on T cells and disable the ability of T cells to fight cancer. An antibody that blocks CTLA-4 is in clinical use; however, the response rate is only 20% at best. Antibodies that block PD-1 are showing an improved response rate of 20-40% in clinical trials. While these results are encouraging, at least half of melanoma patients are still in need of effective treatments. This has prompted investigation into therapies that target other inhibitory proteins. We have found that the inhibitory protein Tim-3 is uniquely expressed on T cells that infiltrate melanoma tumors. Furthermore, Tim-3-expressing cells in melanoma tumors co-express high levels of PD-1 and the inhibitory protein Lag-3, providing a rationale for therapies that block Tim-3 in combination with PD-1 and/or Lag-3 for melanoma treatment. The major goals of this proposal are to determine how best to harness blockade of Tim-3 to improve current melanoma immunotherapy and to identify biomarkers of response to Tim-3-targeted therapies. Antibodies that block Tim-3 are currently in development for clinical translation. Consequently, our results will help guide the clinical application of anti-Tim-3 antibodies for the treatment of melanoma.
Therapeutic Targeting of Melanoma Tumor Initiating Cells
GSK-MRA Young Investigator Award
Alexander Boiko, Ph.D., University of California, Irvine Mentor: Christopher Hughes, Ph.D., University of California, Irvine
Melanoma is one the most aggressive and lethal forms of cancer resulting from tumorigenic transformation of melanocytic cell lineage. Metastatic stage of this disease is virtually incurable and represents a major challenge for current society. In this application I propose to develop immune-therapeutic strategies targeting melanoma tumor initiating cells based on the expression of CD271/NGFR and CD47. In combination with previously defined regimens this therapy would become an important hall mark for the future success of melanoma treatment.
Stromal p16INK4a as a Prognostic Indicator and Therapeutic Target
The Ohio State University-MRA Young Investigator Award
Christin Elizabeth Burd, Ph.D., The Ohio State University Mentor: Gustavo Leone, Ph.D., The Ohio State University
Efforts to understand the biology of melanoma often focus on changes intrinsic to the “seed” or tumor cell. However, recent evidence suggests that normal cells which surround tumors, i.e. “the soil”, can also promote cancer progression. Secretions from such ‘stromal’ cells have been shown in other tumor types to enhance cancer initiation, growth and metastasis. Yet, in melanoma, very little is known about the role of stromal cells in tumor formation and progression. We recently identified p16INK4a as a gene that is active in melanoma stromal cells. Although p16INK4a is not secreted, it is associated with a cellular state called senescence. Senescent cells no longer replicate and instead produce a wide variety of secreted factors that breakdown the surrounding tissue and cause inflammation. Early research suggests that senescent stromal cells promote melanoma development. In support of these data, we find that stromal cells only express p16INK4a in areas where tumors form and not near benign moles. Based upon these data, we believe that stromal p16INK4a expression could be used to more effectively identify melanoma at its earliest and most curable stage. Furthermore, the breadth and intensity of stromal p16INK4a expression may reflect the ability of a tumor to spread or favorably respond to treatment. Our work will 1) examine whether p16INK4a positive stromal cells universally promote melanoma progression, 2) determine the prognostic value of stromal p16INK4a expression in melanoma staging and therapy, and 3) identify tumor-promoting factors secreted by the stroma that could be targeted by future drug interventions.
Therapeutic Target of Uveal Melanoma with GNAQ and GNA11 Mutations
UCSF-MRA Young Investigator Award
Xu Chen, Ph.D., University of California, San Francisco Mentor: Boris Bastian, M.D., Ph.D., University of California, San Francisco
Uveal melanoma(UM) is a common cancer of the eye with high mortality. Once metastatic, the median survival for UM patient is less than 6 months. Currently, there is no effective treatment option available for metastatic UM patients. Recent studies show that 80% of UM contain mutations in the two closely related genes GNAQ and GNA11, which occur early during the progression of UM and drive the proliferation of tumor cells. Unlike mutant BRAF found in other melanomas, GNAQ and GNA11 protein are difficult to target directly with small molecules. Therefore, it is paramount to characterize the effector pathways downstream of these oncoproteins to identify opportunity for targeted therapy. MAP-kinase pathway activation has been shown as one contributing factor to GNAQ-mediated oncogenesis. Recently, we have demonstrated that protein kinase C(PKC) activates MAPK in the context of oncogenic GNAQ or GNA11 and represent a therapeutic target in melanomas with GNAQ/11 mutations. However, which of the 10 different PKC isoforms mediate the effects of those oncogenes remains unclear. Furthermore, monotherapy with either PKC or MEK inhibitor has limited efficacy on GNAQ mutant melanoma due to incomplete suppression of MAPK signaling. We propose: 1) to characterize the PKC isoforms activated by oncogenic GNAQ/11 in melanoma to allow a more precise therapeutic targeting. 2) We will identify how exactly MAPK signaling becomes activated and why PKC or MEK inhibition only incompletely suppress it. We anticipated that our work will lead to a refined understanding of oncogenic signaling in uveal melanoma and further improve therapeutic strategies.
Targeting Autophagy in BRAF-Mutant Melanomas
Whitehead Institute-MRA Young Investigator Award with generous support from the Verschleiser Family
Piyush Gupta, Ph.D., Whitehead Institute for Biomedical Research Mentor: Robert Weinberg, Ph.D., Whitehead Institute for Biomedical Research
The BRAF gene is mutated in approximately half of all melanomas, and its function drives tumor growth and metastasis. For patients with BRAF-mutant melanomas, outcomes have been significantly improved by Vemurafenib and other drugs that selectively bind and inactivate the mutated BRAF protein. However, the majority of melanomas with BRAF mutations do not completely regress in response to Vemurafenib and other targeted drugs. BRAF-mutant melanoma cells that survive Vemurafenib are a reservoir of cells that eventually gives rise to resistance, and inhibiting the survival of these cells would significantly improve the effectiveness of Vemurafenib therapy. Our findings suggest that BRAF-mutant melanomas survive targeted therapies by activating a mechanism of 'self-eating' called 'autophagy'. The experiments in this proposal would translate this preliminary finding to benefit melanoma patients by (i) examining if autophagy inhibitors are effective in combination with Vemurafenib in animal models of melanoma, (2) examining if the extent of autophagy induction correlates with the ability of melanoma cells to survive Vemurafenib in patients, and (3) identifying new chemical molecules that can block autophagy in BRAF-mutant melanoma cells. We believe such chemicals would greatly improve the effectiveness of current therapies by preventing melanoma cells from surviving treatment with Vemurafenib. If successful, the experiments proposed here would lead to new combination treatments for patients with BRAF-mutant melanomas.
Response to PD-1 Inhibitors in Melanoma and Lung Cancer Patients with Brain Metastases
Lung Cancer Research Foundation-LUNGevity-MRA Young Investigator Award
Lucia Jilaveanu, M.D., Ph.D., Yale University Mentor: Harriet Kluger, M.D., Yale University
Melanoma has the highest propensity to metastasize to the brain once the disease has spread, while non-small cell lung cancer (NSCLC) has the highest incidence of brain metastases among all cancers. Approximately 50,000 patients develop brain metastases from these diseases every year. Patients with brain metastases have exceedingly limited therapeutic options since they are typically excluded from clinical trials. Recently a number of new systemic immune therapies, such as nivolumab (BMS-936558) and lambrolizumab (MK-3475), two inhibitors of PD-1 (an immune inhibitory molecule), have led to dramatic responses in metastatic melanoma (MM) and NSCLC. However, these therapies have not been studied in patients with untreated brain metastases. Little is known about immune cells in the brain, and whether the immune system can be stimulated to reject cancer cells. Moreover, little is known about what tumor characteristics are associated with response to MK-3475 in brain metastases. This proposal includes innovative correlative biomarker studies incorporated into a clinical trial uniquely designed to study the activity of MK-3475 in patients with limited, small brain metastases in MM and NSCLC. This drug carries the hope to provide prolonged responses similar to responses seen in other metastatic sites, and might enable patients to avoid radiation therapy, and improve their outcome. As part of this clinical trial, we will collect brain and other metastatic specimens from patients enrolled and study the expression of immune inhibitory molecules utilizing a novel quantitative assay and algorithms that we have developed in preliminary work. These studies will facilitate selection of patients who are more likely to respond to this class of drugs.
Roadmap for the Development of Novel Targeted Therapies for Uveal Melanoma
Stewart Rahr-MRA Young Investigator Award
Nicholas Mitsiades, M.D., Ph.D., Baylor College of Medicine Mentor: Bert O’Malley, M.D., Baylor College of Medicine
Metastatic uveal melanoma is an aggressive cancer with limited response to currently available drugs, even drugs that are active against other melanoma subtypes. Thus, there is an urgent need for new, effective, drugs for this subtype of melanoma. Recent discoveries have improved our understanding of the molecular mechanisms that drive the growth of these melanoma cells. Specifically, two genes, called GNAQ and GNA11, have been found to play an important role in this disease. With the mentorship of Dr Bert O’Malley, who is a member of the National Academy of Sciences and the Institute of Medicine, recipient of the National Medal of Science and internationally recognized as pioneer the fields of nuclear hormone receptors and regulation of transcription, Dr Mitsiades aims to better understand these important molecular pathways, investigate new drugs to block their activity, and improve the treatment of patients with this highly lethal form of melanoma. The planned research studies will involve exploration of these signaling pathways in established cell lines and primary cancer cells and will help identify new drugs to block uveal melanoma growth. These new drugs will be tested in our laboratory during the 3-year period of this study, to obtain more information about their anticancer activity. Experiments in mice with uveal melanoma will also be performed, to further establish the effectiveness of these drugs and evaluate for possible toxic effects. Eventually, these new drugs will be tested in future clinical trials in order to improve outcomes for patients with uveal melanoma.
In Situ Generation of Melanoma-Specific T cells “On Demand”
Stewart Rahr-MRA Young Investigator Award
Matthias Stephan, M.D., Ph.D., Fred Hutchinson Cancer Research Center Mentor: Philip Greenberg, M.D., Fred Hutchinson Cancer Research Center
Skin cancer (melanoma) is often diagnosed after tumor cells have already spread (metastasized), so it is difficult to remove them entirely using surgery and chemotherapy. Fortunately there are cells naturally occurring in our immune system that have the ability to selectively destroy melanoma cells without damaging healthy tissue, but they require stimulation to do so. Vaccines can train the immune system to fight melanoma, and some of these are currently in clinical trials. However, vaccines typically fail to expand anti-tumor immune cells enough to control metastatic diseases. They can also require months to mount an immune response, by which time the disease may become lethal. We propose to create an injectable reagent that can quickly reprogram the patient’s immune cells (particularly T cells) to recognize and destroy melanoma. We hypothesize that T cells circulating in the blood can be genetically reconfigured by targeted, gene-bearing nanoparticles to express receptors that bind specifically to melanoma proteins, which will enable them to bring about rapid and vigorous tumor rejection. Our preliminary experiments have already shown that a new type of nanoparticle we developed can efficiently transfer melanoma-reactive receptor genes into T cells. In the project proposed here, we will (1) establish that nanoparticles can mediate gene transfer into circulating T lymphocytes in vivo, and (2) show that when these nanoparticles carry genes encoding receptors for melanoma-specific antigens, they lead to regression of metastatic melanoma in mice. If successful, our studies may lead to an entirely new type of highly effective therapy for melanoma.
Interrogating the role of S6K as a molecular target in melanoma
The V Foundation-MRA Young Investigator Award with the generous support of Ben LeBow
Jessie Villanueva, Ph.D., The Wistar Institute Mentor: Meenhard Herlyn, D.V.M., D.Sc., The Wistar Institute
Although significant progress has been made treating melanoma and several drugs have been approved for the treatment of advanced disease, several challenges remain. For example, clinical responses are generally short-lived as tumors quickly become resistant and virtually all patients relapse. Moreover, tumors can develop drug resistance through a diverse number of molecular mechanisms, making the development of second-line therapies extremely daunting. Therefore, it is critical to identify therapeutic targets that are common to the majority of resistant tumors. We have recently found that a protein kinase called S6K is activated in melanomas resistant to BRAF and MEK inhibitors. Moreover, we showed that inhibition of this protein using a triple drug combination blocked the growth of resistant tumors. This provides strong rationale for establishing S6K as a novel target for melanoma therapy. Notably, S6K is a common node for most resistance pathways. We propose to investigate the role of S6K in melanoma and determine the therapeutic value of targeting this protein. Towards these goals we will determine the consequences of blocking S6K in melanoma, identify the proteins that are regulated by S6K, and use this knowledge to delineate combinatorial approaches that can lead to long-term tumor remission in a large number of melanomas, including those resistant to BRAF and MEK inhibitors. We expect that the data generated by these studies can be quickly translated into new strategies aimed at maximizing the therapeutic efficacy of MAPK inhibitors in melanoma and provide actionable information that will guide the design of future clinical trials.
Short-Circuiting the Signaling Network in Uveal Melanoma
Theodore Popp, Jr.-MRA Uveal Melanoma Young Investigator Award
Scott Woodman, M.D., Ph.D., University of Texas MD Anderson Cancer Center Mentor: Patrick Hwu, M.D., University of Texas MD Anderson Cancer Center
Uveal melanoma (UM) tumors originate in the eye (a.k.a. primary UM), and can be treated with little risk of recurrence in/around the eye. Unfortunately, in about 50% of cases, well before the primary tumor is recognized/treated, UM cells released into the blood have entered other locations (a.k.a., metastatic UM). Nearly all metastatic UMs involve the liver and are lethal. No treatment has been clinically proven to markedly prolong the time from diagnosis to observable metastasis, slow tumor progression or improve survival. Our understanding of UM primarily comes from studying primary UM tissue from the eye or metastatic UM liver tumors that are large enough to be imaged/biopsied. Thus, very little is known about the particular molecular processes that occur during the period in which UM cells enter the liver then progress to being large tumors. Recent work suggests that UM liver metastases progress in stages, and occupy unique cellular environments in the liver during each stage. It is the hypothesis of this proposal that a thorough molecular analysis of UM cells at each stage of metastatic progression will reveal distinct molecular requirements for uveal metastatic cell growth and survival. These requirements can then be leveraged against the metastatic UM cells to halt tumor progression.
Activating ß-catenin Mutations Cooperate with BRAFV600E to Promote Invasion
UCSF-MRA Young Investigator Award
Iwei Yeh, M.D., University of California, San Francisco Mentor: Boris Bastian, M.D., Ph.D., University of California, San Francisco
Melanoma is a tumor of melanocytes (pigment cells), caused by certain combinations of DNA damage. Many melanomas share a common first event that causes the cells to grow. However, our cells have safety mechanisms in place that stops growth from continuing, resulting in a benign “mole.” Additional DNA damage that disrupts these safety mechanisms leads to melanoma. The ways these safety mechanisms are disrupted are quite diverse and leads to differences in melanoma behavior and response to treatment. Understanding the specific combinations of DNA damage that result in melanoma is important because we can use this knowledge to develop drugs to treat melanoma. Deep penetrating nevi are a type of pre-melanoma that invades deeply in the skin. In typical “moles” the melanocytes become smaller, produce less pigment, and divide less frequently as their distance from the skin surface increases. In contrast, melanocytes in deep penetrating nevi have the same appearance in the deepest part of the tumor, suggesting that they have gained the ability to continue growing at a distance from the skin surface. Our group identified changes in the ß-catenin gene in a type of pre-melanoma tumor called deep penetrating nevi. Similar changes in the ß-catenin gene have been observed in some melanomas. We plan to study deep penetrating nevi and melanomas with ß-catenin mutations in more detail to determine how this specific change contributes to melanoma. We will test how melanomas with changes in ß-catenin respond to existing and novel therapies.
Molecular Modulation of Tumor-Associated Fibroblasts for Melanoma Treatment
University of Cincinnati-MRA Young Investigator Award
Yuhang Zhang, Ph.D., University of Cincinnati Mentor: Zalfa Abdel-Malek, Ph.D., University of Cincinnati
Cutaneous malignant melanoma is notorious for its aggressive clinical behavior, high propensity to metastasize and resistance to therapeutic treatments. For years, researchers have concentrated their efforts almost exclusively on the identification of ways to either selectively kill malignant carcinoma or restrict its growth. Unfortunately, poor treatment outcomes have long frustrated clinicians due to the genetic instability that frequently occurs in malignant melanoma cells, and indeed, a search for more novel strategies is required. The tumor stroma, an integral part of the tumor, becomes reprogrammed by unknown mechanisms to provide a dynamic yet optimal microenvironment for tumor initiation and progression. Strong scientific evidences have shown that infiltrated tumor-associated fibroblasts (TAFs) in the stroma support melanoma to grow, migrate and evade cell death by providing structural and chemical supports. Thus, targeting TAFs to destroy the microenvironment in which tumor cells reside has emerged as a new and promising therapeutic strategy. The objective of this proposal is to explore the molecular mechanisms underlying the synergistic interactions between TAFs and melanoma cells. The knowledge obtained will provide new insights to deepen our understanding of the transdifferentiation of TAFs and their role in tumor development towards an aggressive phenotype. It's our expectation that the successful completion of the proposed study will yield new ideas for melanoma treatment, which could remarkably overcome genetic instability of melanoma cells. Our findings will also contribute meaningfully to the basic principles of tumor biology, which is likely to have broader application to the treatment of other solid tumors.
Inhibiting the TGF-ß Signaling Axis in the Melanoma Microenvironment
Duke-MRA Young Investigator Award in Honor of Frank Courtney
Brent A. Hanks, M.D., Ph.D, Duke University Medical Center Mentor: Gerard Blobe, M.D., Ph.D., Professor of Medicine
Despite recent advancements, there are limited treatment options available for patients with metastatic melanoma. Even for patients eligible for treatment with targeted biological therapy, these strategies have proven to provide relatively short-term benefit. Although immunotherapy has demonstrated the ability to significantly prolong survival, these effects are observed in only a small subset of patients undergoing treatment with these agents. Therefore, there is a significant need to improve the treatment options for patients with advanced melanoma. While current immunotherapies have focused on enhancing the immune response to cancers, they have ignored the ability of tumors to actively interfere with this process. One method that tumors use to suppress the generation of immunity is the production of an immune suppressive factor known as transforming growth factor-ß (TGF-ß). This factor has been shown to inhibit the function of a local antigen presenting cell population known as the dendritic cell, which plays a critical role in directing the generation of tumor-specific immunity. We are proposing to study the combination of a TGF-ß inhibitor with the currently approved immunotherapy agent, anti-CTLA-4 monoclonal antibody (ipilimumab), in a melanoma mouse model that closely resembles the biology of human melanoma. These studies would serve as an important foundation for future clinical trials investigating this treatment combination in patients with metastatic melanoma.
Delineating the Heterogeneity of Response to BRAF Inhibition in Melanoma
The Danny Fund-MRA Young Investigator Award
Michael Berger, Ph.D., Memorial Sloan-Kettering Cancer Center Mentor: David Solit, M.D., Assistant Member, Human Oncology and Pathogenesis Program
The emergence of targeted therapies has profoundly altered the treatment of melanoma patients. Most notably, the BRAF inhibitor vemurafenib has led to significant improvements in survival and quality of life for patients with mutations in the gene BRAF. Nevertheless, complete sustained response to vemurafenib is rare, and heterogeneity of clinical outcomes remains a major challenge. Studies have shown that this variability in response can be at least partly explained by mutations in other genes that co-occur with mutations in BRAF. We have developed a targeted deep sequencing assay enabling us to catalog all mutations and copy number alterations involving all key cancer-associated genes in clinical tumor specimens. Using this platform, we will profile advanced melanomas treated with vemurafenib in order to more comprehensively characterize the spectrum of genomic alterations that co-occur with BRAF mutations and that correlate with drug response. By comparing pre-treatment and disease progression tumors, we will identify alterations that mediate resistance to vemurafenib that may emerge through clonal selection. Finally, in cases where our targeted sequencing assay is unrevealing, we will perform whole genome sequencing and RNA sequencing to discover novel genomic determinants of drug response. Through these efforts, we will provide valuable predictive information for clinicians and patients and lay the foundation for rational BRAF inhibitor-based combination strategies for the treatment of patients with BRAF-mutant melanoma.
A Translational Approach for Developing Combination Therapy in Melanoma
Suzette and Steven Kolitch-MRA Young Investigator Award
Tara C Gangadhar, M.D., The Trustees of the University of Pennsylvania Mentor: Lynn Schuchter, M.D., Division Chief, Hematology-Oncology
Metastatic melanoma has a poor prognosis with an average survival of about one year. Recent advances have lead to the development of targeted therapies that inhibit BRAF, a gene that is abnormally activated in approximately one half of melanomas. Unfortunately, patients quickly develop resistance to BRAF targeted therapies and are still dying of melanoma. Developing new combinations of targeted therapies is essential for improving outcomes in metastatic melanoma. Furthermore, identifying biomarkers that can predict which patients are more likely to respond to a new combination therapy may ultimately guide more individualized treatment in patients with melanoma. Activation of the PI3K gene pathway is one mechanism of resistance to BRAF targeted therapies. Combination therapy inhibiting both PI3K and BRAF may improve outcomes in melanoma; identifying biomarkers that predict response will allow for more personalized individualization of combination therapy. The aims of this project are 1) to conduct a clinical trial of combined PI3K and BRAF targeted therapies in patients with advanced melanoma and 2) to learn about biomarkers that may predict which patients are most likely to respond to combined PI3K and BRAF targeted therapy in order to better personalize care to maximize results in individuals.
Blockade of a Novel CTLA-4 Pathway as a New Approach in Melanoma Therapy
Stewart Rahr-MRA Young Investigator Award
Kok-Fai Kong, Ph.D., La Jolla Institute for Allergy & Immunology Mentor: Amnon Altman, Ph.D., Director, Scientific Affairs
Immunologic targeting of melanoma by CTLA-4 blockade is an effective therapeutic approach. Ipilimumab, a CTLA-4 monoclonal antibody, is FDA approved for treatment of human melanomas. However, combinatorial regimens show promising effectiveness in advanced and metastatic melanomas. I propose to test the preclinical utility of blocking a novel pathway that I discovered between CTLA-4 and an enzyme protein kinase, which is essential for the proper function of regulatory T (Treg) cells, a subset of immune system T cells with the power to suppress immune responses, including against growing tumors. My studies will test whether the absence of the protein kinase can boost anti-tumor immunity and, therefore, restrain tumor growth, by attenuating the function of Treg cells. In addition, I found that genetic deletion of the protein kinase enhances the function of Th9 cells, a different T cell subset with the power to inhibit tumor growth. Therefore, I will also test the hypothesis the lack of the protein kinase can promote the generation and anti-tumor function of Th9 cells. Finally, I will utilize a preclinical animal model of melanoma to determine whether disrupting the ability of CTLA-4 to bind to the protein kinase can result in a beneficial synergistic effect of simultaneously attenuating tumor-promoting Treg function and enhancing tumor-inhibiting Th9 responses. The results that I will generate may provide a preclinical basis for developing novel, clinically useful and selective kinase inhibitory drugs, which, when included in combinatorial regimens with Ipilimumab or other therapies, could greatly improve treatment for patients with advanced melanomas.
Mechanisms of resistance for constitutively-active NRAS Melanoma
Ellis Family-MRA Young Investigator Award in Memory of Hal Ellis
Susana Ortiz-Urda, M.D., Ph.D., The Regents of the University of California, San Francisco Mentor: Pui-Yan Kwok, M.D., Ph.D., Professor, Dermatology
Melanomas are classified based on their genetic alterations. Oncogenic mutations of the RAS family of proteins such as BRAF or NRAS occur in approximately 2/3 of all melanomas.The development in 2010 of Plexxicon a BRAF inhibitor that elicited striking tumor regressions in clinical trials was a milestone event in our understanding of the genetics of this disease. However, the duration of the response was limited due to primary and acquired drug resistance. Recent studies in BRAF inhibitor melanoma patients have shown that there are multiple mechanisms of primary or acquired drug resistance. There are currently not therapies available for NRAS melanomas, however recent studies performed in our and other labs have shown that in order to produce regression on NRAS melanoma tumors several proteins need to be inhibit with specific drugs. Clinical trials combining these drugs are now in progress. We propose to study the possible mechanisms of resistance for NRAS melanoma studying genetic alterations and other cell elements (transcripts) that are being actively expressed at any given time and vary with external environmental conditions.
Augmenting anti-tumor immunity by modulating IL-2/IL-15 receptor binding.
Stewart Rahr-MRA Young Investigator Award
Mark Rubinstein, Ph.D., Medical University of South Carolina Mentor: David Cole, M.D., F.A.C.S., Chairman, Professor of Surgery
The goal of our research is to develop improved immunotherapeutic strategies involving the transfer of tumor-reactive white blood cells (T cells) into patients with metastatic melanoma. This technique is known as adoptive cellular therapy (ACT). ACT is the only therapy that can reliably induce long-term cures in significant frequencies of patients with metastatic melanoma. Despite its promise, there are significant limitations, including life threatening toxicities associated with the treatment, and the majority of patients are not cured. We hypothesize that one of the limitations to ACT being able to work in more patients is a failure of the transferred white blood cells to survive and persist in the cancer patient. To overcome this problem, we propose to evaluate a panel of new growth factors that can be administered to patients after ACT to selectively enhance the survival and function of adoptively transferred white blood cells. Based on our preliminary data, our approach may be significantly less toxic and clinically more efficacious against tumor, as we were able to cure mice with established melanoma tumors with radiation or chemotherapy. As our previous findings (still requiring the use of chemotherapy) are partly the basis for an ACT clinical trial for metastatic melanoma patients being initiated at our institute, funding of this proposal would put my laboratory in a strong position to have a continued impact on the development of future ACT trials both at our institute and elsewhere.
Quantitative single-cell biomarkers of melanoma immunotherapy
Stewart Rahr-MRA Young Investigator Award
Navin Varadarajan, Ph.D., University of Houston Mentor: Richard Wilson, M.D., Professor, Chemical and Biomedical Engineering, and Laszlo Radvanyi, Ph.D., Professor, Melanoma Medical Oncology-Research, University of Texas M.D. Anderson Cancer Center
Melanoma is one of the leading causes of cancer related deaths within the United States. Immunotherapy that aims to harness the impressive capabilities of the human immune system has emerged as one of the frontline therapies for metastatic melanoma. With the recent FDA approval of Ipilimumab, a blocking antibody against the T-cell negative stimulator, CTLA-4, against melanoma, T-cell immunotherapy is now an established cancer therapy. Adoptive cell therapy (ACT) that works directly to harness the cancer-eliminating properties of patient T-cells has shown considerable promise with clinical response rates of ~50% even in stage IV melanoma refractory to all other treatment methods. Essentially, ACT has become the last hope for survival of patients with melanoma that is refractory to conventional therapies. The objective of the current proposal is to perform extensive functional single-cell characterization of the cells used for the combined treatment employing ACT and checkpoint regulation through antibodies, to identify functional attributes of these cells that predict patient outcomes. Identifying single-cell biomarkers will serve to not only predict outcomes but ultimately guide ACT expansion and treatment towards better patient outcomes, a fundamental goal of all cancer treatment.
Targeting melanocyte precursor pathways for melanoma therapy
SkinCeuticals - MRA Young Investigator Award
Barbara Bedogni, Ph.D., Case Western Reserve University - School of Medicine Mentor: Ernest Borden, M.D., Deputy Director, Taussig Cancer Institute, Cleveland Clinic
New therapies against mutated BRAF have shown some promise, however they are applicable to half of the patient population and resistance inevitably sets in within few months of treatment. We propose a novel treatment approach that targets Notch and ERBB signaling cascades and that has the potential to treat patients independently of the dominant mutations that drive the disease. Notch and ERBB, are essential for the well-being of melanocytes and their precursors. Melanomas re-activate them and use them to their advantage to promote growth and survival. While inhibiting either Notch or ERBB alone only marginally affects survival, simultaneous inhibition of both pathways results in over 90% of cell death, with equal efficacy in either mutated or wild type BRAF cells. Our goal is to understand the mechanisms by which Notch and ERBB signaling regulate melanoma cell growth and survival and most importantly, to provide experimental evidence that the pharmacological targeting of these two pathways can effectively halt melanoma growth and metastasis in a majority of melanoma patients. To this end, we will use powerful transgenic mouse melanoma models that very closely recapitulate the biology of human melanoma and are particularly suitable for drug testing. We believe the evidence obtained in this study will be instrumental in supporting the use of Notch and ERBB inhibitors in melanoma therapy. Such compounds already exist and are used for the treatment of other cancers. The applicability to melanoma is therefore a concrete possibility in the short term.
Combining targeted therapy and immunotherapy to treat melanoma
MRA Collaborative Donor Young Investigator Award Fan Pan, M.D., Ph.D., Johns Hopkins University Mentor: Drew Pardoll, M.D., Ph.D., Professor and Co-Director of Immunology
Metastatic melanoma cases in the United States and the death rate of this disease are increasing at a disturbing rate prompting efforts to develop more effective treatments. A strategy called 'immunotherapy' involves stimulating a patient's own immune system to kill tumors. Unfortunately obstacles to effective immunotherapy arise from both tumor cells themselves and certain cells of the immune system. Through a number of poorly understood processes, tumors promote their own growth while suppressing the immune system's tumor-killing capacity. Regulatory T cells ('Tregs') that normally prevent the body from excessive or self-directed immune responses restrain the activation of other immune cells. Another T cell type called 'TH17 cells' initiate processes that aid tumors including tumor spreading (metastasis) and generating new blood vessels to the growing tumor mass (angiogenesis). Previously we found a molecule named 'HIF-1', which is commonly found in tumors, is necessary for generating TH17 cells suggesting that conditions in tumors can generate T cells capable of aiding further tumor development. We propose a strategy in which the generation of both tumor-promoting cells, TH17 and Treg cells are simultaneously abolished. We will test the effectiveness of this approach using known HIF-1 inhibitors (Digoxin, acriflavine) and Treg depleting drugs (cyclophosphamide) in a mouse model for melanoma that closely resembles the human disease. We expect that these drugs by themselves or in combination with a specialized melanoma targeting therapy (Vemurafenib) will have potent anti-tumor effects. In the process of testing this approach, we will shed light on the enigmatic tumor-immune system interaction.
Therapeutic targeting of novel metastatic microRNAs in human melanoma
Amanda and Jonathan Eilian - MRA Young Investigator Award Sohail Tavazoie, M.D., Ph.D., The Rockefeller University Mentor: Barry Coller, M.D., Professor, Physician-in-Chief, VP of Medical Affairs
The major fear that most patients diagnosed with melanoma have is that their cancer will spread or metastasize throughout the body. Currently, our most effective treatment option for stage 1, 2 or 3 melanoma is surgical resection. As such, there are no effective medical therapies for the prevention of melanoma metastasis. I believe that the only way we can combat melanoma metastasis is through enhanced understanding of the underlying biology that drives metastasis. As such, we have invested heavily in the past few years in the development of an in vivo metastasis model of human melanoma metastasis. By using this system, we have discovered two small RNAs (microRNAs) that are present at high levels in highly metastatic melanoma cells. Blocking the activity of these microRNAs strongly blocks melanoma metastasis by both pigmented and non-pigmented melanoma cells. Patients whose melanoma cancers express high levels of these novel small RNAs have much higher rates of melanoma metastasis. We wish to determine how these small RNAs promote metastasis and to identify the genes that they block in order to achieve their aims. We wish to therapeutically block these small RNAs with a novel DNA-like molecule in live mice to determine if this could effectively block melanoma metastasis in human patients. We believe that the identification of the genes that these miRNAs regulate could reveal novel proteins that may possess metastasis suppressive activities in melanoma. This innovative approach has the potential to significantly impact metastatic relapse rates in human melanoma.
Transcriptional elongation in BRAFV600E sensitive and resistant melanoma
Maria and Bill Bell - MRA Young Investigator Award The 2012 AACR-Conquer Cancer Foundation of ASCO Young Investigator Translational Cancer Research Award is providing partial support for this project Richard Mark White, M.D., Ph.D., Memorial Sloan-Kettering Cancer Center Mentors: Joan Massague, Ph.D., Alfred P. Sloan Chair, Cancer Biology and Genetics, Memorial Sloan Kettering Cancer Center and Leonard Zon, M.D., Grousbeck Professor of Pediatrics, Children's Hospital Boston
Recent advances in the treatment of melanoma have seen unprecedented responses in this notoriously difficult disease. The discovery of a key genetic mutation in melanoma, called BRAFV600E, led to the search for specific inhibitors of this gene. The first approved BRAFV600E inhibitor, vemurafenib, produces tumor shrinkage in over 70% of patients and prolongs survival. However, almost all patients become resistant to this drug. Although finding key mutations in melanoma is of great importance, it is abundantly clear that these mutations only produce cancer when in the right context. In melanoma, this "context" is a cell type called a neural crest cell. My laboratory is interesting in discovering whether simultaneously targeting the mutation along with that neural crest context would be a new way of treating cancer. I utilize an unusual model organism for doing these studies: the zebrafish. Unexpectedly, the zebrafish develops very aggressive melanomas that are genetically identical to the human disease. Using this fish, we have been able to discover a number of chemicals which alter this neural crest cellular context. When we combined the BRAF inhibitor with our neural crest inhibitor, we saw the tumors completely regress. We now want to understand if this strategy can be used to prevent resistance to BRAF inhibitors, or be used to treat patients who have already developed such resistance. This would represent a striking example of how studying cancer across species leads to meaningful therapies for human patients.
Targeting NRAS Palmitoylation in Melanoma
Stewart Rahr-MRA Young Investigator Award
Xu Wu, Ph.D., Massachusetts General Hospital Mentor: David Fisher, M.D., Ph.D., Chairman, Department of Dermatology
Melanoma is a highly malignant form of skin cancer that arises from melanocytes. When diagnosed early, more than eighty percent of cases can be successfully treated through surgical resection. However, metastatic melanoma is resistant to currently available treatments and carries a very poor prognosis with a less than ten percent five-year survival rate. Despite efforts to improve skin cancer prevention, the incidence of melanoma has increased significantly over the past decades. MAPK (Ras/Raf) and PI3K/Akt signaling pathways have been implicated in melanoma development. NRAS mutations are found in ~20% of melanoma, and melanoma with NRAS mutation usually has poor prognosis. NRAS mutations have also been linked to the resistance of target-based therapy for melanoma currently in clinic trials. Therefore, it is important to develop new therapeutics that target NRAS. As NRAS protein requires a lipid modification (16-carbon palmitoylation) for its function, blocking this modification can efficiently block NRAS activity in cancer cells. Protein palmitoylation is catalyzed by DHHC (Asp-His-His-Cys)-family protein palmitoyl acyltransferases (PATs). We are developing chemical tools to study NRAS palmitoylation and small molecule inhibitors of NRAS palmitoylation. Such approach could potentially provide new therapeutics for NRAS dependent melanoma.
Development of combined molecular/immunotherapy regimens for human melanoma
Christie's - MRA Young Investigator Award
Christian Blank, M.D., Ph.D., The Netherlands Cancer Institute Mentor: Ton Schumacher, Ph.D., Senior Member, Division of Immunology
The treatment of human melanoma has progressed markedly in recent years. First, recent advances in the genetic characterization of melanoma now allow the specific targeting of the signaling pathway alterations that underlie this disease. As the most prominent example, the targeting of the BRAFV600E mutation with PLX4032 has led to very high response rates, although the duration of these responses is often relatively short. Second, building on the observation that immune recognition is a frequent event in melanoma, a series of antibodies that target inhibitory receptors on T cells has been evaluated in clinical trials. Intriguingly, while the response rate upon blockade of CTLA-4 or PD-1 is lower than that achieved with the targeted drugs, the effect on survival in the subgroup of responding patients is prominent. Based on these recent advances, a key next step will be to develop combination therapies, in which targeted drugs are used to drive cancer regression, and in which antibody administration is utilized to then drive immune reactivity against the liberated antigens. However, our knowledge on how to best combine targeted therapy and immunotherapy is at present highly limited. To address this issue, we have developed a spontaneous mouse melanoma model in which we will determine how combination therapy can best be achieved, using both tumor regression and immunological parameters as readouts. The results obtained in this project should provide the conceptual basis for the design of clinical studies that evaluate the value of combination immunotherapy - targeted therapy for melanoma patients.
Targeting the Pten/PI3K signaling cascade in BRaf600E-induced malignant melanoma
The Canadian Cancer Society is contributing partial funding to this project
David Dankort, Ph.D., McGill University Mentor: William Muller, Ph.D., Chair in Molecular Oncology
The prognosis for those with malignant melanoma today is as poor as it was 25 years ago. Conventional chemotherapies have failed, yet there is hope. Recent genetic and biochemical data have identified genes that are future targeted drugs candidates. Our lab uses state-of-the-art genetically modified mouse models to determine which genes are pivotal in melanoma development, progression, and metastasis. Melanoma represents a failure of built-in mechanisms to control rogue melanocytes that have acquired two types of mutation: i) Oncogene activation, which functions like a gas pedal (increasing tumor cell survival, growth, and migration) and ii) Mutational loss of tumor suppressor genes (TSGs), the tumor developmental "brake pedals." While BRaf is the most frequently mutated oncogene in melanoma, our lab has shown that for mutant BRaf to cause melanomas the TSG Pten must be lost. Unfortunately Pten cannot be restored in tumor cells and has been deemed non-druggable. This is why we seek to determine which gene product(s) biochemically up - and down-stream of Pten are important in melanoma. This is not a blind search; we know that the genes responsible lie within a specific pathway and that most of these are kinases, attractive to pharmaceutical companies. Knowing which are important in melanoma is crucial to developing specific drugs for this disease. Thus we will systematically identify these genes first in cultured cells and then our mouse models. The successful completion of this work will identify key 'druggable' targets that can be translated to the clinic where it matters.
Myeloid derived suppressor cells and immunotherapy outcomes in melanoma
Ellen and Gary Davis Foundation - MRA Young Investigator Award
Alexander Lesokhin, M.D., Memorial Sloan-Kettering Cancer Center Mentor: Jedd D. Wolchok, M.D., Ph.D., Director, Immunotherapy Clinical Trials
Ipilimumab, an antibody that stimulates the immune system, has emerged as a promising treatment option for some patients with advanced melanoma. However, the majority of patients develop toxicity from excess immune stimulation without attaining clinical benefit. These results define the need for: 1) identifying biomarkers of response to Ipilimumab treatment that will enable early identification of patients likely to achieve clinical benefit and 2) studying mechanisms of Ipilimumab failure with the goal of developing additional therapeutic options that enhance outcomes. We have found that myeloid derived suppressor cells (MDSC) increase in quantity after Ipilimumab treatment in patients who do not achieve clinical benefit. Our preclinical work and the work of others support the notion that MDSC limit the effectiveness of T cell mediated tumor immunity. This leads to the hypothesis that MDSC expansion following Ipilimumab is a mechanism of treatment failure. The current proposal aims to: 1) evaluate which MDSC surface genes are amenable to therapeutic targeting; 2) assess which MDSC subsets are increasing in patients that do not benefit from Ipilimumab therapy; and 3) evaluate if antibodies targeting genes overexpressed by MDSC can rescue T cell function. This work will define the role of MDSC in the response to Ipilimumab and potentially identify novel therapeutic targets with potential for improving the outcome of immunotherapy for melanoma and other cancers.
Epigenetic control of PDGFRbeta expression in PLX4032 acquired resistance
Todd Boehly - MRA Young Investigator Roger Lo, M.D., Ph.D., University of California, Los Angeles Mentor: Antoni Ribas, M.D., Ph.D., Associate Professor of Medicine and Surgery
Recently we have witnessed a major breakthrough in the targeted therapy of melanoma. A drug PLX4032 that targets a common melanoma mutation, BRAF(V600E/K), can result in significant tumor shrinkage in about 80 percent of patients treated. One significant barrier to the ultimate success of this approach (i.e., survival benefit) lies in the problem of acquired resistance. This common scenario occurs when tumors initially respond to the drug but then become resistant. Understanding how melanoma tumors escape from PLX4032 following initial response is arguably among the highest priority scientific issues to tackle in melanoma research. We have previously discovered two mechanisms of acquired resistance to PLX4032. One involves a known cancer gene that becomes mutated and activated, bypassing or short-circuiting the effect of the drug PLX4032. The other involves the over-production of a receptor protein that turns on survival pathway(s) that cannot be controlled by PLX4032. In this proposal, we focus on understanding the mechanism of this receptor over-production and hypothesize that it occurs through a non-genetic or so-called epigenetic mechanism. In this scenario, a small population of the melanoma tumor, with more or less the same cancer genome as the tumor bulk, can reversibly adopt an altered but stable state of gene expression, resulting in the re-wiring of survival pathway(s) and the ability to survive and grow in the presence of PLX4032. Resolving a mechanism of this receptor over-production in the course of melanoma escape from PLX4032 should present additional therapeutic opportunities.
Markers and mechanisms of melanoma resistance to combination chemotherapy
Stewart Rahr - MRA Young Investigator Award Aaron Mackey, Ph.D., University of Virginia Mentor: Michael Weber, Ph.D., Director, Cancer Center
Chemotherapies that target a single cancer-causing oncogene are generally unable to provide complete and enduring clearance of the tumor; after an initial wave of tumor cell death, the remaining chemotherapy-resistant tumor cells survive. Using both a small primary panel of current anti-cancer drugs and a larger secondary panel of FDA-approved compounds (including both cancer-related and other drugs), we have identified highly potent pairings of primary cancer drugs with secondary drugs that together kill substantially more tumor cells than either of them kill alone. Study of these synergistic drug pairings reveals how some tumors attempt to evade the killing effects of primary drugs, suggesting that secondary drugs may block such evasion responses. However, these promising results are not universal to all melanoma tumors; only some tumors will respond well to a particular combination of drugs, because either the tumor is resistant to the primary drug or the tumor's evasion of the primary drug effect is not blocked by the secondary drug. These differences in response may be due to one or more DNA mutations among involved genes. Thus, we aim to 1) identify melanoma tumor mutations in a large number of melanomas, 2) assess whether particular genes have been silenced by epigenetic mechanisms, and 3) study each tumor's drug response in light of its individual mutational/epigenetic status, to reveal the mechanism(s) by which sensitivity or resistance is achieved. With this knowledge, we can further develop and prescribe more effective chemotherapies on an individual patient basis.
Novel strategies targeting Treg cell suppression for melanoma immunotherapy
Stewart Rahr - MRA Young Investigator Award Guangyong Peng, M.D., Ph.D., Saint Louis University Mentor: Daniel F. Hoft, M.D., Ph.D., Professor and Director, Division of Immunobiology
Melanoma is the leading cause of cancer-related death in the United States. Increasing evidence suggests that immunotherapy is a promising approach for treating patients with invasive and metastatic melanoma, but the clinical effectiveness is still discouraging so far. Several hypotheses can be postulated to explain the low clinical effectiveness, but it has become clear that regulatory T cells (Treg) exist and induce a suppressive tumor microenvironment to hamper the antitumor immune responses. Thus, the success of immunotherapy against melanoma ultimately depends on how well we understand the suppressive mechanisms mediated by Treg cells in the tumor microenvironment and how to manipulate the immune system to augment antitumor immune responses. We recently discovered a novel suppressive mechanism whereby human Treg cells induce senescence in naive/effector T cells that then exhibit potent suppressive activity. The central hypothesis of this proposal is that human Treg cells not only can directly suppress naive and effector T cells, but also can convert these T cells into senescent cells that possess potent suppressive activity and amplify the immune suppression in the melanoma suppressive microenvironment. To test this hypothesis, we will dissect the mechanisms involved in the differential induction of T-cell senescence, identify unique molecular signaling pathway(s) controlling Treg-induced senescence, and investigate enhancement of antitumor immunity through functional regulations of Treg cells and Treg-induced senescent T cells via TLR8 signaling in melanoma animal models. These studies should lead to novel strategies for manipulation of Treg-induced suppression for the treatment of human melanoma and other cancer as well.
Feedback adaptation of RAF-MEK-ERK signaling in BRAF mutant melanomas
PricewaterhouseCoopers - MRA Young Investigator Award Christine Pratilas, M.D., Memorial Sloan-Kettering Cancer Center Mentor: Neal Rosen, M.D., Ph.D., Enid A. Haupt Chair in Medical Oncology
For the majority of patients with advanced melanoma whose tumors have a mutation in BRAF, novel therapies directed against mutant RAF are effective and represent a great advance in treatment of this disease. However, most responses are incomplete and the majority of patients' tumors will stop responding after about seven months. Many investigators are trying to determine why tumors become resistant to RAF inhibitor therapy. We however are trying to understand why responses to RAF inhibitor therapy are incomplete or suboptimal, and have observed that inhibition of the signaling pathway in these cells is associated with a subtle reinduction of other pathway elements in a negative feedback loop. Our work shows how this occurs and why the addition of a second inhibitor of the pathway results in enhanced and more prolonged response of the tumor. The studies outlined in the proposal are designed to 1) achieve a better understanding of the feedback circuits that limit the response to RAF inhibitors alone, 2) determine the impact of the reactivation on other important elements of the pathway, and 3) test whether combinations of drugs that limit the feedback reactivation result in better responses in models of BRAF mutant melanoma. The translational impact of these studies is the design of novel combination therapies for patients, which enhance the initial response to RAF inhibitor treatment.
Targeting the LKB1-AMPK signaling pathway in malignant melanoma
Elizabeth and Oliver Stanton - MRA Young Investigator Award Bin Zheng, Ph.D., Columbia University Medical Center Mentor: Riccardo Dalla-Favera, M.D., Uris Professor of Pathology and Director, Herbert Irving Comprehensive Cancer Institute
BRAF kinase is a major oncogenic driver and therapeutic target in malignant melanoma. Recently, the BRAF kinase inhibitor PLX4032 (also known as RG7204) has shown remarkable anti-tumor activity in melanoma clinical trials. However, around 30 percent of patients developed keratoacanthomas-type squamous cell carcinomas (SCC). In addition, most of the patients developed drug resistance during the course of treatment. We have recently discovered a novel bi-directional crosstalk between BRAF and the tumor suppressor LKB1-AMPK pathway, an important signaling pathway involved in the regulation of cancer cell growth and proliferation. Based on our findings, we hypothesize that combinatorial targeting both pathways is a more effective approach to treat malignant melanoma and holds the potential to overcome current limitations associated with BRAF inhibitors. Preclinical studies have suggested that activating the LKB1-AMPK pathway is a promising strategy for cancer therapeutics. Metformin, an activator of the LKB1-AMPK pathway, is currently being used for treating type II diabetes and potentially can be adapted for cancer treatment. The goal of this proposal is to assess the therapeutic benefit of using AMPK activators (such as metformin and its analog phenformin), in combination with the BRAF inhibitors in melanoma treatment. We will evaluate the combinatory effect of AMPK activators and BRAF inhibitors on inhibiting tumor growth in preclinical mouse models. Moreover, we will investigate the potential of AMPK activators on preventing the development of BRAF inhibitor-induced SCC and the emergence of resistance to BRAF inhibitors. Our studies will provide important rational basis to develop better targeted therapy of malignant melanoma.
Circulating microRNAs as diagnosis and staging biomarkers for melanoma
Latham & Watkins - MRA Young Investigator Award Li Zhou, M.D., Henry Ford Health System Co-Mentors: Qing Sheng Mi, M.D., Ph.D., Director, Immunology Program, and Henry Lim, M.D., Chair, Department of Dermatology
Malignant melanoma (MM) is the most aggressive form of skin cancer. Development of minimally invasive tests for the detection and monitoring of MM could revolutionize present clinical management. Although conventional strategies for blood-based biomarker discovery have shown promise in other cancers, the development of clinically validated detection markers for MM remains an unmet challenge. New approaches that can complement and improve current strategies for early diagnosis and prediction of MM are urgently needed. MicroRNAs (miRNAs) are small RNA molecules that modulate gene functions and play important roles in a wide range of physiologic and pathologic processes, including cancer. Recent data from our laboratory and others indicated that miRNA expression is dysregulated in melanoma cells and tumors, and serum miRNA expression profiles are altered during MM development, raising the possibility that the circulating miRNAs may serve as MM specific biomarkers. In this proposal, we will test if miRNAs could be an ideal novel class of serum biomarkers for the early diagnosis and assessment of MM progression. We will first use miRAN global gene expression profile to further identify potential serum miRNA biomarkers, which may change during MM progression, then develop serum miRNA assays suitable for large cohort analyses to validate it. Finally, we will test if serum miRNAs could serve as predictive biomarkers for the risk of MM progression and assess treatment outcome. The results from the proposed studies may revolutionize present clinical management, including early diagnosis of progressive MM, confirmation of stage, estimating prognosis, and predicting therapeutic efficacy.
Counteracting metastatic spread and outgrowth by MCSP-targeted therapy
SkinCeuticals - MRA Young Investigator Award Edwin Bremer, Ph.D., University Medical Center Groningen Mentor: Wijnand Helfrich, Ph.D., Head Surgical Research Laboratories
Life expectancy of melanoma patients diagnosed with metastases is very limited, because metastasized melanoma is largely resistant to current treatment regimens. Therefore, new approaches that block the spread and outgrowth of metastasizing melanoma cells are urgently needed. Here, we aim to develop such novel approaches using two proteins normally involved in the fight against cancer in the human body. These proteins are called TRAIL and Galectin-9. TRAIL specifically induces cell death in melanoma cells, but not in normal cells, whereas Galectin-9 specifically blocks the ability of melanoma cells to metastasize. Unfortunately, these potentially promising proteins are not ideally equipped to hunt down melanoma cells by themselves. To overcome this hurdle, we fused TRAIL and Galectin-9 to a so-called antibody fragment that is uniquely suited to hunt down melanoma cells. This antibody fragment recognizes and strongly binds to a protein called MCSP, which is highly expressed on melanoma cells. Of note, MCSP also promotes metastasis formation, but this pro-metastatic activity is inhibited by the antibody fragment. Therefore the two fusion proteins we designed will: 1. selectively hunt down and bind to melanoma cells; 2. inhibit pro-metastatic signaling by MCSP; and 3. simultaneously attack tumor cells by TRAIL or Galectin-9. The current project aims to preclinically evaluate the approach outlined above and is expected to yield a candidate drug that will be particularly suited for the prevention/inhibition of melanoma metastases.
Identifying therapeutic targets for melanoma brain metastases
PricewaterhouseCoopers - MRA Young Investigator Award Michael Davies, M.D., Ph.D., University of Texas M.D. Anderson Cancer Center Mentor: Gordon B. Mills, M.D., Ph.D., Chair, Department of Systems Biology
One of the most common and devastating complications of advanced melanoma is the development of brain metastases. Unfortunately, there are no effective treatments for this complication, and patients with brain metastases survival less than 4 months on average. In preliminary studies, we have demonstrated that melanoma brain metastases have significant molecular differences when compared to metastases from other sites in the body. We propose to study a set of patients for whom we have tissue samples from both their brain metastases and metastases from other sites to determine what factors and pathways contribute to the aggressive nature of these tumors. These studies should improve our understanding of brain metastases, and set the stage for rational clinical trials for these patients.
Epigenomic analysis of melanoma metastatic behavior
Cartier - MRA Young Investigator Award Remco van Doorn, M.D., Ph.D., Leiden University Medical Centre Mentor: Rein Willemze, M.D., Professor and Chair of Dermatology
Most patients currently diagnosed with melanoma present at an early stage of the disease, when the prognosis after surgical removal of the primary tumor is favorable. However, a subset of patients with early melanoma lesions will develop metastatic disease. Metastasis, the spread of tumor cells from a primary tumor to distant sites, currently poses the biggest problem to melanoma treatment and is the main cause of death. Our means of identifying those patients at increased risk of metastasis, who might benefit from additional treatment are limited. This is partly due the fact that it is not well known what actually drives melanoma tumor cells to invade and spread to foreign tissues. Recent findings suggest that the capacity to metastasize is engrained and detectable in tumor cells of the primary melanoma. This study is aimed at identifying alterations in DNA methylation, a chemical modification of the molecules that carry genetic information, in metastatic melanoma. Tumor cells often harbor many DNA methylation alterations, which deregulate gene activity. We will examine whether the pattern of DNA methylation in melanomas that metastasize is different from the pattern observed in melanomas that do not metastasize. We expect to find specific molecular markers that can predict whether a primary melanoma will show metastatic spread. In addition, we will examine if and how these DNA alterations promote the metastatic behavior of melanoma tumor cells. In doing so, we hope to find new approaches to treatment by specifically targeting molecules that contribute to metastatic behavior of melanoma cells.
miRNA down-regulation in melanoma - Diagnostic and therapeutic implications
Stewart Rahr - MRA Young Investigator Award Raya Leibowitz-Amit, M.D., Ph.D., Sheba Medical Center Mentor: Shai Izraeli, M.D., Head, Leukemia and Childhood Malignancies Section
Metastatic melanoma is a devastating disease with currently limited treatment options. miRNAs are small RNA species within cells that regulate gene expression. Aberrant expression of miRNAs leads to cancerous transformation, but their role in melanoma is still unknown. We have observed that many miRNAs are not expressed in malignant melanocytes in comparison to normal melanocyets. Interestingly, many of the genes encoding these miRNAs are found in very close proximity in a chromosomal region known to be implicated in differentiation and development. Indeed, some of these miRNAs were shown to suppress the growth of several cancer types but not of melanoma so far. Our preliminary results demonstrate that in some melanoma cell lines, these miRNAs are silenced because of a chromosomal deletion. Conversely, in other cell lines these miRNAs are most likely silenced by a mechanism that merely alters the chromosomal material without deleting it (termed 'epigenetic modification'), because treatment of the cells with epigenetic modifiers restores their expression.
We plan to further investigate the mechanism and timing of miRNA silencing during melanocyte transformation. We also plan to molecularly characterize the sub-group of melanoma patients with the potential to undergo tumor suppression in response to epigenetic modifiers. Eventually, we plan to design a clinical trial evaluating the use of such agents (already approved for hematological malignancies) in this specific patient sub-group. Our translational research will hopefully yield a new treatment approach along with a novel molecular assay that predicts response, thus enlarging our therapeutic arsenal in this yet incurable disease.
18F Labeled benzamides for pre-clinical PET imaging of melanoma metastases
Zhen Cheng, Ph.D., Stanford University Mentor: Sanjiv Sam Gambhir, M.D., Ph.D., Director, Molecular Imaging Program
Cheng synthesized two novel PET scanning probes that bind with melanoma associated melanin. [18F]FDG is the most widely used PET probe for imaging metastatic melanoma in the clinic, but there is a need for additional probes that can be more specific and detect smaller metastases. In malignant melanoma, melanin formation is highly increased because tyrosinase activity is significantly elevated. In preclinical models, these new probes targeted primary and pulmonary melanotic metastatic lesions with excellent imaging quality and had the advantage of low accumulation in healthy organs.
Combining an MDM2 inhibitor with chemotherapy for the treatment of melanoma
Sanjev Kumar, PhD, University of Michigan Mentor: Shaomeng Wang, Ph.D., Professor and Co-director, Molecular Therapeutics Program
The p53 tumor suppressor gene is mutated in half of human cancers; however, the wild-type status of p53 is retained, but remains inactive, in a high percentage (~85%) of human melanomas. The key mechanisms for the functional inactivation of wild-type p53 include the direct interactions of p53 with MDM2 or MDMX proteins, and overexpression of Bcl-2/Bcl-xL proteins, which inhibit p53-induced cell death. Dr. Kumar found that concurrent targeting of Bcl-2/Bcl-xL proteins and the p53 pathways with small molecules induced rapid and robust apoptosis in preclinical models. This research resulted in two candidate drugs that reactivate p53 that have been licensed by a company to initiate phase I clinical testing.
The role of oncogenic signaling pathways in human melanoma immune evasion
Patrick Ott, M.D., New York University Mentor: Nina Bhardwaj, M.D., Ph.D., Professor and Director of Tumor Vaccine Program
Dendritic cells are promising as a vaccine platform because they are able to induce strong T cell responses that can lead to melanoma destruction. This study aims to investigate whether the melanoma microenvironment, possibly driven by cell signaling pathways that are upregulated in melanoma cells (such as the MAPK pathway), negatively impacts dendritic cell function. This study will also explore whether signaling pathway blockade in melanoma cells can possibly reverse a negative effect on dendritic cells and other immune cells. I expect that these investigations will lead to a more detailed understanding of the interface between melanoma biology and the melanoma-specific immune response and allow the rational integration of oncogenic pathway inhibition into dendritic cell vaccination protocols in melanoma.
Dr. Bullock has been working to optimize a vaccination strategy that elicits the highest magnitude helper T cell response to specific targets expressed by melanoma cells. Dr. Bullock also identified targets on "corrupted" T cells (helper T cells that have been converted to regulatory T cells that suppress immune response to the tumor) in order to disrupt their function or prevent the conversion from occurring. A combination approach that suppresses and bypasses regulatory mechanisms and supports survival of cells is necessary for eliciting large populations of CD4 cells. They have also found that the presence of these cells enhances the trafficking of cytotoxic T cells to the tumor.
Regulation of T cellchemokine receptor expression during vaccination: Tumor-targetedimmunotherapy
David Mullins, Ph.D. University of Virginia
Dr. Mullins confirmed that CXCR3 (a chemokine receptor previously found to be expressed on a subset of melanoma patients' CD8 T cells) serves to assist these T cells in migrating into melanomas, and vaccination with melanoma-derived peptides and adjuvant can induce CXCR3-positive T cells in greater that 95 percent of patients. His lab discovered that cells can produce these chemical beacons following local administration of IFN-gamma. In part with funding by the NIH, Dr. Mullins will initiate a Phase I trial to assess the effects of dual administration of vaccination and IFN-gamma treatment of the tumor to optimize CD8 T cell tumor infiltration.
Defining the role of inducible co-stimulator (ICOS)-expressing T cells against melanoma
Padmanee Sharma, M.D., Ph.D. University of Texas, M.D. Anderson Cancer Center
Research indicates that patients who have improved survival after ipilimumab (anti-CTLA-4) treatment have sustained elevations of numbers of ICOS-expressing T cells. ICOS is a stimulatory co-regulator of T cell anti-tumor immune responses. To understand the role of these T cells in the anti-tumor response, studies conducted in mouse models showed that the ICOS pathway is necessary for optimal anti-tumor immune response.