miR-1301/TRIAP1 Axis Participates in Epirubicin-Mediated Anti-Proliferation and Pro-Apoptosis in Osteosarcoma.

PURPOSE

Epirubicin is one of the most effective drugs against osteosarcoma. miR-1301 is involved in the occurrence and development of osteosarcoma. Whether miR-1301 is responsible for the chemosensitivity of osteosarcoma cells to epirubicin remains largely unknown.

MATERIALS AND METHODS

U2OS and SAOS-2 cells were treated with various concentrations of epirubicin. Flow cytometry was employed to evaluate cell apoptotic rate. Cell proliferation was measured by Cell Counting Kit-8 assay. Western blot and quantitative real-time polymerase chain reaction were utilized to detect the expressions of B-cell lymphoma-2 (Bcl-2), Bcl-2 assaciated X protein (Bax), cleaved-caspase-3, cleaved-poly (ADP-ribose) polymerases (PARP1), TP53-regulated inhibitor of apoptosis 1 (TRIAP1), and microRNA-1301 (miR-1301). The relationship between miR-1301 and TRIAP1 was determined by luciferase reporter assay.

RESULTS

Epirubicin inhibited proliferation in a dose-dependent manner, induced apoptosis, decreased the expression of Bcl-2, and increased the expressions of Bax, cleaved-caspase-3, and cleaved-PARP1 in osteosarcoma cells. miR-1301 was downregulated in U2OS and SAOS-2 cells. Importantly, epirubicin significantly increased the levels of miR-1301. Overexpression of miR-1301 suppressed proliferation and promoted apoptosis. Interestingly, those effects were enhanced by epirubicin. In contrast, miR-1301 depletion attenuated the epirubicin-mediated anti-osteosarcoma effect. miR-1301 negatively regulated the expression of TRIAP1 in U2OS and SAOS-2 cells. Furthermore, epirubicin inhibited the mRNA and protein levels of TRIAP1 by upregulating miR-1301 levels. Epirubicin suppressed cell proliferation by downregulating TRIAP1.

CONCLUSION

miR-1301 was implicated in the chemosensitivity of osteosarcoma to epirubicin by modulating TRIAP1.