Melanoma is an aggressive type of skin cancer known for its rapid spread and frequent resistance to current treatments. Many advanced melanomas carry genetic mutations in the NRAS gene, making them particularly challenging to treat effectively. Recently, new medications known as multi-RAS inhibitors have shown promising initial results; however, melanoma cells quickly develop resistance, diminishing the effectiveness of these therapies. Our research identified that melanoma cells become drug-resistant through changes in gene expression levels—a process called epigenetic regulation.

In our studies, we discovered that drugs known as histone deacetylase inhibitors (HDACi), which influence how genes are activated or silenced, can help melanoma cells overcome resistance and regain sensitivity to treatments. Notably, even brief exposure to HDACi drugs can produce lasting effects, maintaining the reversal of drug resistance long after treatment ends. Our ongoing work aims to rigorously evaluate this innovative approach through detailed laboratory models and animal studies. By understanding precisely how HDACi drugs reverse melanoma resistance and by determining the best ways to use these drugs clinically, we aim to develop safer, more durable, and effective therapies for patients suffering from difficult-to-treat NRAS-mutant melanoma.

Tumor infiltrating lymphocyte (TIL) therapy represents a promising approach for the treatment of patients whose disease does not benefit from conventional immunotherapies. While TIL resulted in tumor shrinkage or disappearance in approximately one third of patients with advanced melanoma, it has become increasingly important to develop novel strategies for TIL ex vivo expansion to develop superior TIL in greater numbers and anti-tumor activity that when adoptively transferred into patients will provide improved rates of response and enhanced clinical benefit. Current standards for TIL therapy include surgical excision of patient’s tumor typically from the most accessible metastatic sites, growth of TIL outside of patient’s body in cultures supported by Interleukin-2 (aka T cell growth factor; TCGF) and subsequent infusion of these expanded TIL into patients after undergoing chemotherapy. The first part of the project evaluatesif the quality of TIL can be improved through addition of a combination costmulatory CD40L-4-1BB antibody into ex vivo TIL cultures. We hypothesize that CD40L-4-1BB will increase number of TILs and result in production of better quality of TIL which is characterized by higher percentage of tumor specific so called “reactive” TIL. Adding additional growth molecules during growth of TIL outside of body hasthe potential to improve TIL characteristics and translate to improved responses to TIL therapy and survival of patients with melanoma. The second part of this project investigates whether TIL can successfully growth from core biopsy samples and evaluates what unique clinical, pathological, and immunological characteristics of tumor tissue impact the quality of the TIL product to inform best anatomic sites for initial TIL harvest. Current standard of performing surgery of tumors to growth TIL is mainly based on targeting either skin or lymph node samples. Tumors are heterogenous and with this strategy visceral metastases are often not used to grow TIL, indeed, those metastatic sites also appear to determine disease outcome. We postulate that obtaining tumor cores from visceral metastatic locations such as lung, liver will result in superior generation of tumor-reactive TIL outgrowth and effector functionality. We will obtain additional cores “passes” from biopsies which were ordered as standard of care procedure for generation of TIL and study how the TME of core biopsies impacts the quality of expanded TIL. The studies will involve morphological and cellular interrogation of tumor sections and profiling of the TIL product. If successful, these studies will establish a workflow for effective outgrowth of TIL from core biopsies which can avoid the need for additional surgical procedures for patients with advanced melanoma. Furthermore, this strategy will open a new avenue for patients those tumor metastatic locations would otherwise disqualify them from access to receiving TIL therapy due to their “unresectable” tumors.

Radiation can be used as a vaccine, to increase the effect of immunotherapy. We call this Radvax, which is promising. Even in melanoma patients who failed anti-PD-1 treatment, 44% of patients had their tumor shrink when radiation was added. We need to understand when and how to use radiation with other immunotherapies. One of the most important breakthroughs recently is the idea that the bacteria in our intestines can impact how a patient responds to immunotherapy. In this pilot study, we will study the effect of Radvax treatment on CD8 T cells that recognize these intestinal bacteria. The hope is that this information can eventually be used to predict who will benefit from immunotherapy and who will get immune side effects. We will study this in a Radvax clinical study where melanoma patients receive radiation and a combination of two immune checkpoint blockade antibodies targeting PD-1 and CTLA-4. Understanding how to combine radiotherapy with immunotherapy will give us new treatment options for cancer patients.

Although immune checkpoint inhibitors (ICI) such as programmed death-1 (PD-1) blockade have made meaningful advances in the treatment of melanoma, drug resistance has limited their therapeutic efficacy as approximately 70% of patients still experience disease progression within 5 years. Therefore, understanding mechanisms of ICI therapy resistance and identification of biomarkers for predicting response to ICI treatment are unmet needs. Along with new blood vessel formation in the tumor by angiogenic factors, vascular destabilization is recognized as a hallmark of tumor growth and metastasis. Emerging evidence suggests a fundamental link between tumor vascular abnormalities and ICI therapy resistance whereby vascular destabilization impairs the immune cell infiltration to the tumor and promotes and immune evasion. Consistently, recent clinical and preclinical evidence has highlighted the importance of targeting proangiogenic factors to improve immunotherapy efficacy in cancer. Angiopoietin-2 (Ang2), which binds to the receptor tyrosine kinase Tie2, is a potent vessel-destabilizing factor and its upregulation correlates with poor prognosis and disease progression in many types of tumors. Building on our previous work on Ang2/Tie signaling in the tumor microenvironment, in this project we propose to identify Ang2/Tie signaling molecules as predictive biomarkers for immune evasion and ICI therapy resistance in melanoma. Successful completion of this project could significantly enhance the clinical management in patients with melanoma receiving ICI therapy.

MRF Breakthrough Consortium Pilot Translational Award – Minah Kim, PhD