Chemotherapy-Induced Immune Modulation: Unraveling CAF-CD۴+ T Cell Interactions in Colorectal Cancer Pre- and Post- Treatment

Colorectal cancer (CRC) is a leading cause of cancer-related mortality, with the tumor microenvironment (TME) significantly influencing disease progression and treatment response. Cancer-associated fibroblasts (CAFs) and CD۴+ T cells are critical players in the TME, yet little is known about how chemotherapy affects their interactions. This study examines the impact of chemotherapy(۵-fluorouracil, leucovorin, capecitabine ,and oxaliplatin) chemotherapy on CAF-CD۴+ T cell interactions in primary CRC, with a focus on how treatment alters specific CD۴+ T cell subpopulations. Methods: Single-cell RNA sequencing (scRNA-seq) data were obtained from six CRC samples from the GSE۱۷۸۳۱۸: three treatment-naive and three treated. Low-quality cells were filtered, and the samples were analyzed using Seurat and integrated using Harmony to correct for batch effects. CD۴+ T cells were annotated based on established literature. CellChat was used to infer cell-cell communication between CAFs and CD۴+ T cell subpopulations before and after treatment. EnrichR was employed to identify altered pathways driven by CAF ligand-receptor interactions pre- and post-treatment. Results: Various cell types, including NK cells, epithelial cells, T cells, B cells, plasma cells, mast cells, monocytes, and macrophages, were identified. CD۴+ T cells were annotated into functional clusters, including activated, naïve, Th۱۷, memory, regulatory, and Temra cells. CellChat analysis revealed that CAFs interacted with all CD۴+ subtypes. Pre-treatment interactions were dominated by COL۱A۱/CD۴۴ and COL۱A۲/CD۴۴ ligand-receptor pairs, primarily through the COLLAGEN signaling pathway, with moderate interaction probabilities . Post-treatment, while collagen-related interactions persisted, MIF/CD۷۴-CXCR۴ interactions emerged, particularly with T helper (Tfh), regulatory (Treg), and effector memory (Tem) cells. These interactions showed increased strength , indicating a shift toward immune modulation following treatment. Conclusion: Chemotherapy significantly alters the interaction landscape between CAFs and CD۴+ T cell subpopulations in CRC. While collagen-related signaling remains crucial, the emergence of MIF/CD۷۴-CXCR۴ interactions post-treatment suggests a shift toward immune regulation, particularly with Tregs and memory T cells. These findings provide insights into how chemotherapy reshapes the immune environment in CRC, with potential implications for enhancing therapeutic strategies.

کلیدواژه ها:

Colorectal cancer ، FOLFOX chemotherapy ، CAF-CD۴+ T cell interactions ، Tumor microenvironment ، Immune modulation