Abstract
Radioresistance poses a major challenge in the treatment of advanced rectal cancer. Therefore, understanding the detailed mechanisms of radioresistance may improve patient response to irradiation and the survival rate. To identify the novel targets that modulate the radiosensitivity of rectal cancer, we performed small RNA sequencing with human rectal cancer cell lines. Through bioinformatics analysis, we selected microRNA-310a (miR-130a) as a promising candidate to elucidate radioresistance. miR-130a was dramatically upregulated in radiosensitive rectal cancer cells and overexpression of miR-130a promotes rectal cancer cell radiosensitivity. Mechanically, miR-130a reversed the epithelial-mesenchymal transition phenotype of rectal cancer cells following inhibition of cell invasion upon irradiation. Moreover, miR-130a also inhibited the repair of irradiation-induced DNA damage followed by cell death. We identified that SOX4 was a direct target of miR-130a. Overexpression of SOX4 reversed the promotion activity of miR-130a on radiosensitivity. Together, our findings suggest that miR-130a functions as a radiosensitizer in rectal cancer and reveals a potential therapeutic target and preoperative prognostic marker for radiotherapy.