Pilot Award Program

Adoptive T cell Therapy in Melanoma: Ex vivo Selection and Expansion of Circulating Uveal Melanoma-specific T Cells

Metastatic uveal melanoma (MUM) is a rare cancer that develops when primary ocular melanoma spreads to other body tissues. The liver is the most common organ affected, followed by the lungs, brain, and bone. Once metastatic disease develops, it progresses quickly, and many patients do not survive more than a year. The available treatment options produce only a marginal effect on the survival rate.

Recently, cancer therapy was revolutionized by immunotherapy, which helps a person’s own immune cells to recognize and destroy cancer cells effectively. One main type of immune cell that does this is called a T cell. T cells can recognize cancer-specific proteins. The recognition event triggers T cells to attack and kill the target. Several types of immunotherapies are successfully used to treat skin melanoma. The first attempts to apply immunotherapy in the treatment of uveal melanoma were disappointing, leading to the conclusion that uveal melanoma is cancer-resistant to immunotherapy. However, recent clinical trials with adoptive tumor-infiltrating T cell transfer challenge this view.

The T cell transfer involved growing T cells derived from tumor tissue in a laboratory, expanding them, and then transferring the cell product into patients after a lymphodepleting treatment. About one-third of patients with metastatic uveal melanoma had tumor regression when treated with adoptive transfer of the tumor-derived T cells. However, the response predominantly induces transient partial tumor regression. In nonresponding patients, insufficient tumor-specific T cell reactivity was observed. Moreover, the patient must undergo surgery to procure tumor tissue for T cell expansion, which is not always feasible for patients with liver metastases.

Our proposal aims to develop T cell based therapy using T cells from patients’ blood. The frequency of tumor-specific T cells in the blood is lower than in tumor tissue. However, higher T cell numbers represent memory T cells, which can persist as long-lived cells and then expand and convert into effective cancer cell killers in a patient’s body. We will apply a novel approach to enrich the adoptive transfer product with T cells reactive toward UM.

During T cell growth outside of the body, we will treat them with particular pharmacological inhibitors that reprogram T cell metabolism, augmenting their expansion, survival, and memory potential. The resulting UM-specific T cell population will be used in a collaborative project (with Drs. Vitali Alexeev, Yuri Sykulev and Mizue Terai) for the isolation of single tumor-reactive T cells and cloning their T cell receptor genes encoding a protein that determines T cell anti-cancer reactivity. The genes will be used to engineer T cells with UM reactivity for “off-shelf” T cell adoptive therapeutics. This proposed approach for producing T cells for adoptive transfer should improve the frequency and durability of clinical responses and the general applicability of this treatment modality. We hypothesize that the project execution will accelerate the transition of the experimental treatment modality to clinical settings.

Leveraging GSDMD-mediated Pyroptosis to Induce Antitumor Immunity as a Therapeutic Strategy for Uveal Melanoma

Uveal melanoma is the deadliest form of adult eye cancer. Patients with metastatic disease have poor survival rates and limited treatment options. Metastatic uveal melanomas respond poorly to immunotherapy, a type of treatment that allows the immune system to recognize and kill tumors. Different forms of cell death can improve the recognition of tumors by the immune system. A form of cell death called pyroptosis occurs when proteins in the cells, gasdermins, poke holes on the cell surface, causing various cellular components to leak out and stimulate the immune system. Pyroptosis improves immunotherapy in several cancers. Thus, we are exploring whether a particular form of pyroptosis, driven by gasdermin D, might make uveal melanomas more recognizable to the immune system.

Within this project, our aims include: 1) studying pyroptosis through gasdermin D and its effect on tumor growth in a uveal melanoma-like model system. We hypothesize that pyroptosis through gasdermin D will slow tumor growth by engaging the immune system, and 2) testing whether pyroptosis induction through gasdermin D can improve the effect of immunotherapy in uveal melanoma-like tumor models. Specifically, we will investigate the best timing of pyroptosis induction to improve immunotherapy and lead to immune responses that can impact distant tumors that model metastases. In collaboration with The Wistar Institute, we will screen thousands of anti-cancer drugs to discover which can cause pyroptosis through gasdermin D. Then, we will test the identified drugs’ efficacy for slowing uveal melanoma tumor growth. With this aim, we expect to leverage pyroptosis to improve immunotherapy in uveal melanoma and discover new treatments for uveal melanoma.

This award was funded through a generous donation in honor of H. Gregory Fairhurst.

Leveraging Syngeneic Uveal Melanoma Models to Assay a Novel Immune Checkpoint Target

Uveal melanoma (UM) is a deadly malignancy and the most common eye tumor in adults. UM that is limited to the eye can be successfully treated. However, once the disease has spread to the liver, patients have a poor prognosis. Liver UM is difficult to treat and is resistant to many types of therapeutic approaches.

In this study, we seek to better understand how the liver and the patient’s immune system respond to UM tumor lesions. To accomplish this, we will utilize a novel mouse-based UM cell line that will enable immune-based studies. With this model system, we are particularly interested in targeting a protein, PSGL-1, known to inhibit anti-cancer immunity in other cancer types. We will determine how PSGL-1 contributes to the immune response in UM liver tumors, thereby establishing proof-of-concept for targeting this protein as a novel therapeutic approach.

This award was funded through a generous donation made in honor of H. Gregory Fairhurst.

Preclinical Evaluation of RNA Vaccine Targeting Uveal Melanoma

Metastatic uveal melanoma (MUM) is a fatal malignancy that most often develops in the liver and for which there is no cure. It is very intractable to the treatment. Most of the drugs that have been successful in treating metastatic skin melanoma have been ineffective against MUM. It was proposed that these medications were ineffective in MUM patients due to a lack or paucity of the MUM-recognizing white blood cells (T cells) in these patients. To overcome this barrier, we hypothesize that active vaccination with portions of the UM-specific and UM-associated proteins could be used to “educate” T cells to recognize and kill MUM. In support of this hypothesis, we obtained encouraging preliminary data demonstrating that our novel ribonucleic acid (RNA)-based vaccine could activate UM-targeting T cells in laboratory culture conditions. The primary goal of the proposed research is to test RNA vaccine platform to activate MUM-reactive T cells for long-lasting, protective immunity.

Within this project we will: (1) investigate RNA vaccine-mediated activation of donor/patient-derived T cells in laboratory culture condition, (2) explore whether these cells could target and kill human MUM growing in experimental animals, and (3) test the capacity of the direct vaccination to activate MUM-targeting T cells in experimental animals. It is expected that the proposed studies will identify a potent RNA vaccine for T cell “education.” Such vaccine could be used in high-risk, primary UM patients to prevent reoccurrence and metastatic spread. It is anticipated that the results of this investigation will pave the way toward clinical translation of the proposed vaccination approach.

Pyroptosis and Lipid Metabolism in Uveal Melanoma

Melanoma of the eye occurs in the uveal tract (composed of the choroid, the ciliary body, and the iris) and is referred to as uveal melanoma (UM). UM is the most common malignancy of the eye in adults and accounts for 5% of all melanomas, with ~2,000 adults diagnosed every year. Half of UM patients develop advanced stage disease (metastasis) within 15 years of diagnosis, typically in the liver. UM that spreads through the body (metastasizes) to the liver is invariably fatal. Despite the recent FDA approval of tebentafusp, there remains an urgent need for effective therapeutic strategies to treat late-stage UM. Unlike cutaneous melanoma, metastatic UM responds poorly to targeted therapies, including MEK inhibitors (MEKi). Importantly, UM frequently does not respond to immune checkpoint inhibitors (ICi) such as Yervoy plus either Keytruda or Opdivo. The goal of our proposed studies is to improve the therapeutical options for UM patients.

We aim to explore the use of statins as a novel therapeutical option to improve the response to targeted therapy and reduce metastasis in UM. We propose to investigate the combination of FDA-approved MEK inhibitors with statins. Importantly, statins are also FDA-approved and present a high safety profile. Preclinical studies indicate that these agents synergize with targeted therapy and prevent metastasis. Thus, our studies have the potential to be translated into the clinical setting.

Our studies address the unmet need to optimize therapeutic strategies in metastatic UM. Our proposed research will integrate in vitro and in vivo approaches to investigate the effects of statins on metastasis onset and response to targeted therapy. At the end of this study, we aim to provide the scientific basis for more effective therapeutic strategies for this deadly form of melanoma.