RBCK1 contributes to chemoresistance and stemness in colorectal cancer (CRC).

Chemotherapy is an essential treatment for colorectal cancer (CRC). However, colorectal cancer cells often develop resistance to chemotherapeutic drugs, resulting in relapse and poor patient prognosis. Growing studies indicate that tumor cells with stem cell-like features could promote resistance to chemotherapeutic agents. In this study, we demonstrated that RANBP2-type and C3HC4-type zinc finger-containing 1 (RBCK1) expression was markedly increased by cancer-associated fibroblasts (CAFs). First, we found that RBCK1 was over-expressed in chemoresistant CRC tumors and promoted chemoresistance in CRC cells. High RBCK1 expression was significantly correlated with poor prognosis in CRC patients. RBCK1 inhibition promoted sensitivity to chemotherapeutic drugs, and prevented migration and invasion in CRC cells. In addition, RBCK1 knockdown reduced cancer stemness by decreasing the expression of Nanog, Oct4, Sox2 and Klf4 in CRC cell lines. Furthermore, RBCK1 expression was significantly up-regulated in CRC cells cultured with conditioned medium (CM) derived from CAFs. Moreover, CAF-derived CM enhanced stemness and chemoresistance in CRC cells by over-expressing RBCK1. The in vivo experiments confirmed that RBCK1 knockdown promoted the chemotherapeutic drug sensitivity in a xenograft model. Taken together, these finding indicated that RBCK1 modulated chemosensitivity in CRC, and could be served as a promising therapeutic target for CRC prevention.