Effect of miR-135b inhibitor on biological characteristics of osteosarcoma cells through up-regulating PPM1A.

miR-135b is expressed abnormally in various tumors and plays an important role in the occurrence and development of tumors bydifferent pathways. The role of miR-135b in osteosarcoma (OS) and its mechanisms were uncertain. The study aimed to clarify the role of miR-135b in osteosarcoma (OS) cells and explore the effect of miR-135b inhibitor on the biological characteristics of OS cells. Firstly, Compared with adjacent bone tissues, the expression of miR-135b was increased and inversely correlated with potential target-PPM1A mRNA, while the expression of PPM1A was decreased in OS tissues. Dual luciferase reporter assay was used to verify that PPM1A was a target gene of miR-135b and RT-PCR and western blot were used to detect that miR-135b negatively regulated expression of PPM1A in MG63 and U2OS cell lines. After transfection, miR-135b inhibitor significantly inhibited cell proliferation and invasion both in MG63 and U2OS cells and blocked cell cycle in the G2/M phase and induced cells apoptosis, while PPM1A knockdown abolished the inhibition of miR-135b inhibitor on the proliferation and invasion of OS cells. In conclusion, miR-135b is up-regulated in OS cells and down regulating miR-135b expression could inhibit the proliferation and invasion of OS cells by up-regulating PPM1A. miR-135b might be a new therapeutic target of OS.