FKBP10 promotes M2 polarization of macrophage via MEK/ERK/CXCL8 axis and facilitates tumor progression in clear cell renal cell carcinoma.

The progression and therapeutic response of clear cell renal cell carcinoma (ccRCC) are critically shaped by the complex interactions between tumor cell heterogeneity and the tumor immune microenvironment (TIME). However, a comprehensive classification of the ccRCC ecosystem and its clinical relevance is lacking. To address this, we utilized comprehensive bioinformatics approaches to analyze ten public single-cell RNA sequencing datasets from 194 samples across 118 ccRCC patients. Across 1,172,154 cells, we identified four TIME subtypes (immune activation, innate immunity, immunosuppressive myeloid [ISM], and immune exclusion) and six functional states of tumor cells (metabolic, angiogenic, stress-responsive, antigen-presenting, cell cycling, and epithelial-mesenchymal transition [EMT]). The interplay between these components defined four immune ecosystems, among which the ISM subtype, coupled with the EMT tumor state was associated with the poorest prognosis. Using machine learning-based prognostic modeling, we highlighted FKBP10 as a critical prognostic gene. Mechanistically, we demonstrated that FKBP10 not only promoted EMT but also activated the MEK/ERK/ELF3 signaling axis, leading to an increased secretion of CXCL8 by tumor cells. Tumor-derived CXCL8, in turn, drove macrophage M2 polarization and myeloid-derived suppressor cell (MDSC) recruitment, thereby reinforcing an immunosuppressive TIME. Furthermore, targeting FKBP10 synergized with anti-PD-1 therapy in suppressing tumor growth