miR-3942-3p Increases the radiosensitivity of nasopharyngeal carcinoma through negatively regulating BARD1

Luxing Peng; Jiaxin  Chen; Heming   Lu; Jinjian Cheng; Qiang Pang; Youjun  Wu; Xu Liu

doi:10.18388/abp.2020_5791

Luxing Peng Department of Radiotherapy, Center of Oncology, People’s Hospital of Guangxi Zhuang Autonomous Region, China
Jiaxin Chen Department of Radiotherapy, Center of Oncology, People’s Hospital of Guangxi Zhuang Autonomous Region, China
Heming Lu Department of Radiotherapy, Center of Oncology, People’s Hospital of Guangxi Zhuang Autonomous Region, China
Jinjian Cheng Department of Radiotherapy, Center of Oncology, People’s Hospital of Guangxi Zhuang Autonomous Region, China
Qiang Pang Department of Radiotherapy, Center of Oncology, People’s Hospital of Guangxi Zhuang Autonomous Region, China
Youjun Wu Department of Radiotherapy, Center of Oncology, People’s Hospital of Guangxi Zhuang Autonomous Region, China
Xu Liu Department of Radiotherapy, Center of Oncology, People’s Hospital of Guangxi Zhuang Autonomous Region, China

DOI: https://doi.org/10.18388/abp.2020_5791

Abstract

Nasopharyngeal carcinoma (NPC) has high incidence in China and East and Southeast Asia. The study was performed to investigate the effect of microRNA3942-3p (miR-3942-3p) on the radiosensitivity of NPC. Compared with non-cancer tissue, NPC had significantly lower miR-3942-3p expression. X-irradiation (IR) reduced the expression of miR-3942-3p in a dose-dependent way in NPC cells. Down-regulation of miR-3942-3p using miR-3942-3p inhibitor resulted in significantly increased cell viability, decreased apoptosis of CNE1 cells. Bax decreased and Bcl2 increased after IR. The expression of BARD1, a cancer predisposing gene, was elevated in NPC tissue. It was confirmed to be a target of miR-3942-3p using luciferase reporter assay. Down-regulation of BARD1 using siRNA significantly reduced cell viability and significantly increased apoptosis both before and after IR. The same response was observed when miR-3942-3p mimics was used to transfect BARD1-overexpressing CNE1 cells, suggesting the up-regulation of miR-3942-3p could sensitize CNE1 cells to X-rays via BARD1. Our data demonstrate that up-regulation of miR-3942-3p could sensitize NPC to X-rays via a downstream target BARD1, offering potential new strategies for radiotherapy of NPC.