KH-type splicing regulatory protein controls colorectal cancer cell growth and modulates the tumor microenvironment

Background & Aims: KH-type splicing regulatory protein (KHSRP) is a multifunctional nucleic acid binding protein. KHSRP regulates transcription, mRNA decay and translation, and miRNA biogenesis. These distinct functions are associated with key aspects of cancer cell biology: inflammation and cell-fate determination. However, the role KHSRP plays in colorectal cancer (CRC) tumorigenesis remains largely unknown. Methods: We investigated the oncogenic role of KHSRP in CRC using a combination of in silico analysis of large datasets, ex vivo analysis of protein expression in patient samples, and mechanistic studies using in vitro models of CRC. Results: KHSRP was expressed in the epithelial and stromal compartments of both primary and metastatic tumors. Elevated KHSRP expression was found in tumor versus matched normal tissue in a cohort of 62 patients. This finding was validated in larger independent cohorts in silico. KHSRP expression was a prognostic indicator of worse overall survival (HR=3.74, 95% CI = 1.43-22.97, p=0.0138). Mechanistic data in CRC cell line models supported a role of KHSRP in driving epithelial cell proliferation in both a primary and metastatic setting, through control of the G1/S transition. Additionally, epithelial KHSRP was involved in promoting a pro-angiogenic extracellular environment, as well as regulating the secretion of oncogenic proteins involved in diverse cellular processes such as migration and response to cellular stress. Conclusion: Our study has uncovered novel mechanistic-based data on the tumor- promoting effects of KHSRP in CRC.