BACKGROUND MiR-301a and miR-301b are 2 oncomiRs involved in multiple types of cancer. In this study, we explored the expression change of miR-301a and miR-301b in prostate cancer cells in hypoxia and studied their regulation of autophagy and radiosensitivity of prostate cancer cells. MATERIAL AND METHODS QRT-PCR was performed to quantify the expression change of miR-301a and miR-301b in hypoxia. Their effects on autophagy were measured by Western blot analysis, and their effects on radiosensitivity were measured by clonogenic assay and flow cytometry. In addition, the regulation of miR-301a and miR-301b on NDRG2, a tumor-suppressor gene in prostate cancer, was also studied. The effect of miR-301a/b-NDRG2 axis on autophagy and radiosensitivity of prostate cancer cells was further investigated. RESULTS MiR-301a and miR-301b are 2 hypoxia responsive miRNAs that are significantly upregulated in hypoxia in prostate cancer cells. Higher level of miR-301a and miR-301b expression results in elevated autophagy and increased radioresistance in LNCaP cells. MiR-301a and miR-301b simultaneously target NDRG2 and decrease its expression. Knockdown of NDRG2 leads to increased autophagy and radioresistance. CONCLUSIONS MiR-301a and miR-301b are 2 hypoxia-responsive miRNAs that decrease autophagy of prostate cancer cells in hypoxia by targeting NDRG2. Through downregulating NDRG2, miR-301a and miR-301b can promote radioresistance of prostate cancer cells.
Medical science monitor : international medical journal of experimental and clinical research. 2016 Jun 21*** epublish ***
Wei Wang, Mingbo Liu, Yawei Guan, Qingwu Wu
Department of Radiation Oncology, Henan Provincial People's Hospital, Zhengzhou, Henan, China (mainland)., Department of Radiation Oncology, Henan Provincial People's Hospital, Zhengzhou, Henan, China (mainland)., Department of Urology, General Hospital of Beijing Military Region, PLA, Beijing, China (mainland)., Department of Medical Imaging, The First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan, China (mainland).