MPP8 Promotes Proliferation and Restrains Apoptosis in Osteosarcoma by Regulating p38MAPK Pathway

Osteosarcoma is the most common primary bone malignancy. We aim to investigate that role of M-phase phosphoprotein 8 (MPP8) on proliferation and apoptosis in osteosarcoma. Briefly, the current research reported an in vitro study investigating the role MPP8 in OS tumorigenesis. Consequently, we found that the MPP8 expression was upregulated in osteosarcoma tissues and in osteosarcoma cell lines. Interestingly, MPP8 knockdown via shRNA restrained the cell viability and proliferation of U2OS and Saos-2 cells. In addition, MPP8 knockdown promoted the apoptosis of U2OS and Saos-2 cells, while MPP8 overexpression promotes proliferation and inhibited the cell apoptosis of osteosarcoma cells. These results suggested that MPP8 may serve as a contributor for osteosarcoma growth and inhibition of MPP8 may help restrain the development of osteosarcoma. Importantly, we found that MPP8 overexpression suppressed the protein levels of HOXA5, p38 alpha MAPK, increased cell proliferation and inhibited cell apoptosis, while co-transfection with HOXA5 overexpression suppressed the cell proliferation and increased cell apoptosis. These results indicated that MPP8 contributed to cell proliferation and the underlying mechanism might be involved with HOXA5/ p38 alpha MAPK pathway.