Integrated analysis of single-cell and bulk RNA sequencing to construct a CD8 + T cell-related immune gene signature in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor that responds poorly to immunotherapy. The pivotal influence of CD8 + T-cell infiltration on immunotherapy has been documented in various solid tumors. However, the specific contribution of CD8 + T cell-associated immune genes (TIGs) to the tumor immune microenvironment remains unclear. We obtained CD8 + T cell-related immune genes from the INNATE and IMMPORT databases. Univariate analysis and lasso regression analysis were utilized to screen hub TIGs and develop a prognostic signature, the TIGs score. This score was used to evaluate prognosis, immunocyte infiltration, cancer-associated signaling pathways, and the potential responsiveness of immunotherapy. The transcriptomic data and single-cell data from the GSE183795 and GE212966 datasets are employed to validate the reliability of the findings. Our findings suggest that patients with low TIGs scores have stronger immune effector functions and immune checkpoint activation, resulting in a more favorable response to PD-L1 inhibitors. TIGs scores were significantly correlated with various molecular characteristics and clinical outcomes, such as tumor mutation burden, multiple tumor-associated pathways, and chemotherapeutic drug sensitivity. PSME2 was identified as a potential prognostic biomarker for predicting survival in patients with PDAC. This study elucidates the intricate regulatory mechanisms of TIGs within the tumor immune microenvironment of pancreatic cancer. Our findings strongly suggest that the TIGs score is a robust prognostic marker for prognosis and immunotherapy responsiveness. Additionally, targeting PSME2 may offer a novel avenue for enhancing the effectiveness of immunotherapy in pancreatic cancer.