The miR-34a-5p promotes the multi-chemoresistance of osteosarcoma via repression of the AGTR1 gene

Background: Chemoresistance hinders the curative cancer chemotherapy. MicroRNAs (miRNAs) are key players in diverse biological processes including the chemoresistance of cancers. Methods: A RNA-seq-based miR-omic analysis of osteosarcoma (OS) cells was performed to detect the levels of miR-34a-5p. Bioinformatics analysis revealed that AGTR1 is one of the target genes of miR-34a-5p. The mRNA and protein levels of AGTR1 were detected in both the miR-34a-5p-mimic transfected G-292 and miR-34a-5p-antagomiR transfected SJSA-1 cells. The involvement of AGTR1 with OS chemoresistance was validated by the experiments with siRNA-mediated repression or overexpression of the AGTR1 gene. Results: We showed that miR-34a-5p promotes the multi-chemoresistance of OS. The angiotensin II type 1 receptor (AGTR1) gene, is one of the targets of miR-34a-5p in OS and thus negatively correlates with OS chemoresistance by systematic investigations of a multi-drug sensitive (G-292) and resistant (SJSA-1) OS cell lines. Down-regulation of the AGTR1 expression by siRNA passivates G-292 cells and suppresses cell apoptosis, while over-expression of AGTR1 sensitizes SJSA-1 cells and thus promotes the drug-triggered cell death. Conclusions: The miR-34a-5p and its target gene AGTR1 are the potential targets for an effective chemotherapy of OS. Our results also provide novel insights into the effective chemotherapy for OS patients.