Introduction: Despite that renal cell carcinomas (RCC) are heavily infiltrated by intratumoral T cells, >70% of RCC patients fail to respond to immune checkpoint inhibitors (ICIs) immunotherapy. Our knowledge of the cellular and molecular mechanism underlying ICI efficacy in RCC is limited. Tumor cell-intrinsic IFNg responsivity has vital yet opposing functions in ICI efficacy by inducing the expression of antigen presenting molecules and T cell recruiting chemokine ligands from tumor cells, while in parallel increasing the expression of therapeutically relevant immune checkpoint ligands (IC-L) such as PD-L1. Major obstacles to improving ICI efficacy in RCC are the lack of (1) knowledge as it pertains to tumor-intrinsic IFNg responsivity; and (2) human models that recapitulate tumor cell heterogeneity and ICI responses. Methods: We leverage patient-derived organoids (PDO) to determine IFNg-responsivity by analyzing the expression of antigen presenting molecule and IC-Ls. For each PDO, we generated blood and tumor derived PDO-reactive T cell lines that were phenotyped to determine T cell subset composition and inhibitory receptor expression. We performed PDO/T cell co-culture assays (PDOTs) and measured intracellular cytokine production to determine the increase in anti-tumor T cell reactivity in response to PD1 ICI and in combination with PDO relevant IC-Ls. Results: We identified patient-specific intratumoral heterogeneity in IFNg responsivity to reveal IFNg-dependent and independent IC-L expression and soluble mediator secretion. Paired PDO IC-L expression and TIL checkpoint receptor expression data were used to identify ICI strategies in patient-specific manner. PDOTs were used to identify patient-specific therapeutically relevant IC-Ls, which in combination with PD-1 ICI improved anti-tumor T cell responses in autologous PDOT co-cultures. Functional immunophenotyping showed that in addition to CD8 T cells, intratumoral double negative T cells play a key role in ICI responses in RCC. Conclusions: PDO model intra-tumoral and inter-patient heterogeneity in the tumor-immune phenome and IFNg responsivity. Our paired autologous PDOT biobank enables patient-specific identification of targetable immune checkpoints and PDOT co-cultures enable characterization of patient-specific anti-tumor response to rationally design ICI combination therapies that augment anti-tumor T cell responses in RCC. SOURCE OF Funding: none
