Investigating the anti-tumor roles of tumor-draining lymph nodes in renal cell carcinoma - Project Summary/Abstract While cancer immunotherapy has transformed the treatment of solid tumors, most patients do not receive durable clinical benefit. CD8+ T cells are critical mediators of anti-tumor immunity, targeting and killing cancer cells, with immune checkpoint blockade (ICB) therapies designed to amplify their tumor-specific cytotoxic functions. Under chronic antigen stimulation in the tumor microenvironment (TME), exhausted CD8+ T cells progressively differentiate from progenitor exhausted (Tpex) cells with self-renewal capacity, to intermediate exhausted (Tex-int) cells with peak cytotoxicity, and finally to terminally exhausted (Ttex) cells with diminished proliferation and effector functions. In mouse lung cancer models, the tdLN was identified as a reservoir of Tpex that differentiate into tumor- infiltrating lymphocytes (TILs), sustaining anti-tumor immune responses over time. Additionally, Tpex are the primary target of ICB, expanding and differentiating into Tex-int that mediate effective anti-tumor immunity. However, given the limited efficacy of ICB in most patients, it remains unclear whether these findings are generalizable across cancer types (or are model-specific), and whether this biology translates to human cancers. To investigate this, our lab has extensively characterized TILs in patients with clear cell renal cell carcinoma (RCC) through single-cell RNA sequencing (scRNA-seq), establishing that tumor-specific CD8+ T cells are overwhelmingly found within exhausted T cell compartments. Further, scRNA-seq of human RCC TILs found a higher baseline of Tpex and a greater shift from Tpex to Ttex in patients responding to anti-PD-1-based ICB compared to non-responders, suggesting Tpex are critical for ICB response in RCC. However, the tumor- specificity, phenotypic states, tissue compartmentalization, and effector functions of CD8+ T cells in solid tumors are not fully understood. In Specific Aim 1, I will leverage collaborations with surgeons, pathologists, and clinical oncologists to identify tumor-specific CD8+ T cells in matched tumor and tdLN specimens from RCC patients, characterizing their lineage relationship, phenotype, and effector functions. This will define the role of the periphery and T cell subsets in anti-tumor responses in human solid tumors. In Specific Aim 2, I will utilize a dominant antigen-engineered syngeneic mouse model of RCC to track tdLN-derived tumor-specific CD8+ T cell migration, investigating whether tdLN anti-tumor responses are consistent across immunotherapy-treated cancers and providing critical insights into T cell migration in RCC. Achievement of these aims will uncover the role of the tdLN and exhausted CD8+ T cell populations in sustaining anti-tumor immunity, assess their relevance to RCC and other solid tumors, and identify key T cell subsets as candidates for adoptive cell therapy. The collaborative environment at Yale University, paired with state-of-the-art resources and facilities, along with the dedicated mentorship of Dr. Braun and Dr. Bosenberg, provides an ideal setting to complete this research and develop into an independent investigator.
