Activated Schwann cells promote tumor growth in colon cancer

Schwann cells, traditionally recognized as glial cells of the peripheral nervous system, have emerged as pivotal cellular constituents within the tumor microenvironment. Colon cancer exhibits significant nerve dependence; however, the roles of Schwann cells in colon cancer progression remain insufficiently understood. Here, we identified a significant increase in tumor-associated nonmyelinating Schwann cells within colon tumor samples compared to their normal tissue counterparts. Furthermore, the elevated abundance of these cells was associated with poorer clinical outcomes in colon cancer. Within colon tumor tissues, Schwann cells displayed elevated expression of c-Jun, a key gene involved in their activation and reprogramming. Knocking down c-Jun hampered Schwann cell activation. Single-cell RNA sequencing analysis uncovered that glial cells engage in the most robust cell-cell interactions with malignant cells and fibroblasts. Co-culture experiments demonstrated that tumor cells and cancer-associated fibroblasts specifically promoted c-Jun activation in Schwann cells, whereas co-culture with immune cells did not elicit a similar response. Under In vivo conditions, Schwann cells enhance tumor growth in a c-Jun-dependent manner. Moreover, c-Jun knockout in Schwann cells orchestrated a reprogramming of their secretome, exemplified by a notable reduction in IL-6, a key effector of their tumor-promoting activity. Collectively, our study elucidates the critical role of activated Schwann cells in colon cancer, which may offer a novel therapeutic strategy for treatment.