miR-375 targeting autophagy-related 2B (ATG2B) suppresses autophagy and tumorigenesis in cisplatin-resistant osteosarcoma cells.

Acquisition of drug resistance is an enormous obstacle for osteosarcoma (OS) treatment. Copious microRNAs (miRNAs) have been reported to participate in chemoresistance. However, the role and molecular basis of miR-375 in cisplatin (Cis/DDP) sensitivity in OS remain unclear. Expression of miR-375 and autophagy-related 2B (ATG2B) in OS was examined by reverse-transcription qPCR (RT-qPCR) and western blot assay. The value of 50% growth inhibitory concentration (IC50) for DDP was determined by Cell Counting Kit (CCK)-8 assay. Cell autophagy was measured with cell proliferation, apoptotic rate, acridine orange-positive cells, and LC3-II/LC3-I ratio determined by MTT assay, flow cytometry, and western blot assay. The candidate target of miR-375 was predicted using TargetScan and was further validated by luciferase reporter and western blot analyses. Mice xenograft model was established to further investigate the tumorigenesis of U2OS/DDP in vivo. In the study, miR-375 was downregulated in DDP-resistant OS tissues and cell lines U2OS and MG63. Elevated miR-375 or reduced ATG2B decreased cell proliferation, acridine orange-positive cells and LC3-II/LC3-I ratio, and increased apoptosis rate in U2OS/DDP and MG63/DDP cells, as accompanied with lower IC50 value for DDP. ATG2B was identified to be a target of miR-375. Re-expression of ATG2B abolished miR-375-mediated effects on cell autophagy. Moreover, the reintroduction of miR-375 slowed down tumor growth of U2OD/DDP cells in vivo. In conclusion, miR-375 suppressed cells autophagy and tumor growth in DDP-resistant U2OS/DDP and MG63/DDP cells by targeting ATG2B, providing a potential target for the treatment of DDP-resistant OS.

KEYWORDS: {{ getKeywords(articleDetailText.words) }}