miR-519b-3p promotes responsiveness to preoperative chemoradiotherapy in rectal cancer patients by targeting ARID4B.

Recent evidences demonstrate that preoperative chemoradiotherapy (pCRT) followed by mesorectal excision is an effective therapy for patients with locally advanced rectal cancer (LARC). Nevertheless, the predictive molecular biomarkers for the response of patients to CRT remain largely unknown. Here we showed that the expression of miR-519b-3p was correlated with the responsiveness to pCRT in patients with LARC. We found that miR-519b-3p was highly expressed in responsive LARC samples. And we showed that miR-519b-3p may serve as a novel predictive marker by ROC analysis. In addition, overexpression of miR-519b-3p enhanced responsiveness to chemoradiation in vitro. Mechanistically, we found that miR-519b-3p directly bond to the 3' UTR of ARID4B mRNA whose expression was inversely correlated with miR-519b-3p expression. Finally, we performed functional experiments and showed that miR-519b-3p was directly involved in response to pCRT in rectal cancer patients in an ARID4B-dependent way.