RESUMO
KRAS inhibitors have demonstrated exciting preclinical and clinical responses, although resistance occurs rapidly. Here, we investigate the effects of KRAS-targeting therapies on the tumor microenvironment using a library of KrasG12D, p53-mutant, murine pancreatic ductal adenocarcinoma-derived cell lines (KPCY) to leverage immune-oncology combination strategies for long-term tumor efficacy. Our findings show that SOS1 and MEK inhibitors (SOS1i+MEKi) suppressed tumor growth in syngeneic models and increased intratumoral CD8+ T cells without durable responses. Single-cell RNA sequencing revealed an increase in inflammatory cancer-associated fibroblasts (iCAF), M2 macrophages, and a decreased dendritic cell (DC) quality that ultimately resulted in a highly immunosuppressive microenvironment driven by IL6+ iCAFs. Agonist CD40 treatment was effective to revert macrophage polarization and overcome the lack of mature antigen-presenting DCs after SOS1i+MEKi therapy. Treatment increased the overall survival of KPCY tumor-bearing mice. The addition of checkpoint blockade to SOS1i+MEKi combination resulted in tumor-free mice with established immune memory. Our data suggest that KRAS inhibition affects myeloid cell maturation and highlights the need for combining KRAS cancer-targeted therapy with myeloid activation to enhance and prolong antitumor effects. SIGNIFICANCE: Combination of SOS1 and MEK inhibitors increase T cell infiltration while blunting pro-immune myeloid cell maturation and highlights the need for combining KRAS cancer-targeted therapy with myeloid activation to enhance and prolong anti-tumor effects.
Assuntos
Carcinoma Ductal Pancreático , Imunoterapia , Neoplasias Pancreáticas , Proteínas Proto-Oncogênicas p21(ras) , Proteína SOS1 , Microambiente Tumoral , Animais , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/imunologia , Carcinoma Ductal Pancreático/patologia , Camundongos , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologia , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/imunologia , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/genética , Proteína SOS1/genética , Proteína SOS1/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Imunoterapia/métodos , Linhagem Celular Tumoral , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Camundongos Endogâmicos C57BL , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , FemininoRESUMO
Knowledge of immune cell phenotypes in the tumor microenvironment is essential for understanding mechanisms of cancer progression and immunotherapy response. We profiled 45,000 immune cells from eight breast carcinomas, as well as matched normal breast tissue, blood, and lymph nodes, using single-cell RNA-seq. We developed a preprocessing pipeline, SEQC, and a Bayesian clustering and normalization method, Biscuit, to address computational challenges inherent to single-cell data. Despite significant similarity between normal and tumor tissue-resident immune cells, we observed continuous phenotypic expansions specific to the tumor microenvironment. Analysis of paired single-cell RNA and T cell receptor (TCR) sequencing data from 27,000 additional T cells revealed the combinatorial impact of TCR utilization on phenotypic diversity. Our results support a model of continuous activation in T cells and do not comport with the macrophage polarization model in cancer. Our results have important implications for characterizing tumor-infiltrating immune cells.