MIR-183-5P PROMOTES CISPLATIN RESISTANCE IN OSTEOSARCOMA CELLS BY TARGETING PPP2R2A

Huabin Wang¹, Yuanxiang Liu¹, Haitao Zeng¹, Xiang Wang¹, Shengzhong Yi^{2, *}

¹Bone and Tissue Surgery, Hubei Cancer Hospital, Wuhan City, Hubei Province, 430079, China - ²Department of Thoracic Surgery, Hubei Cancer Hospital, Wuhan City, Hubei Province, 430079, China

Objective: This study aims to explore the specific role and relevant molecular mechanisms of miR-183-5p in osteosarcoma (OS). 

Methods: Mir-183-5p over-expression or low expression OS cells and PPP2R2A over-expression OS cells were constructed by transfection with miR-183-5p mimics or inhibitors and PPP2R2A plasmid. The expression levels of miR-183-5p mRNA in normal human osteoblasts and OS cells were detected by qRT-PCR experiments. The expression level of PPP2R2A protein was detected by Western blot. The cell viability of each group of transfected cells was detected by MTT experiments, and the proliferation level of OS cells was evaluated. The caspase-3 expression levels in each group of cells were detected using a caspase-3 analytical kit. The migration and invasion ability of each group of CRC cells were detected by using a cell scratch test and a transwell invasion test, respectively. The TargetScan database was used to predict the direct target protein of miR-183-5p and the possible binding sequence. The activity of luciferase in CRC cells with miR-183-5p and PPP2R2A3’-UTR plasmid co-transfection was detected using double luciferase experiments. GEO was used to analyze the expression differences of miR-183-5p in each clinical sample of the GSE70367 data set. 

Results: GEO analysis, as well as qRT-PCR experiments, showed that miR-183-5p was significantly highly expressed in OS patients as well as in OS cell lines. MiR-183-5p mimics significantly promoted the proliferation, invasion and migration of OS cells while inhibiting cisplatin-induced apoptosis and cell viability, whereas miR-183-5p inhibitors played an opposing role. In addition, the TargetScan database predicts that PPP2R2A may be the direct target protein of miR-183-5p. Simultaneously, double luciferase experiments verified that miR-183-5p could directly act on PPP2R2A, and miR-183-5p negatively regulated PPP2R2A levels at transcriptional and protein levels. Meanwhile, mandatory over-expression of PPP2R2A markedly reversed cisplatin resistance in OS cells induced by miR-183-5p over-expression. 

Conclusion: This study demonstrated that miR-183-5p promoted the proliferation, migration and invasion ability of OS cells by inhibiting the expression of PPP2R2A while promoting the production of cisplatin resistance in OS cells.