REG γ knockdown suppresses proliferation by inducing apoptosis and cell cycle arrest in osteosarcoma

Background. Osteosarcoma (OS) is the most common malignant bone tumor with high mortality in children and adolescents. REG gamma is overexpressed and plays oncogenic roles in various types of human cancers. However, the expression and potential roles of REG gamma in osteosarcoma are elusive. This study aims at exploring possible biological functions of REG gamma in the pathogenesis of osteosarcoma and its underlying mechanism. Methods. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blotting and immunohistochemistry (IHC) were performed to detect the expression levels of REG gamma in OS tissues and cell lines. Then, the effects of REG gamma expression on OS cell proliferation in vitro were analyzed by Cell Counting Kit-8 (CCK-8), ethylene deoxyuridine (EdU), colony formation, flow cytometry. The protein levels of apoptosis and cell-cycle related proteins were evaluated using western blotting. Results. In present study, we found for the first time that REG gamma is overexpressed in osteosarcoma tissues and cell lines and knockdown of REG gamma significantly inhibits cell proliferation and induces apoptosis and cell cycle arrest in osteosarcoma cells. Furthermore, we observed that p21, caspase-3 and cleaved caspase-3 are increased while the expression of cycinD1 and bcl-2 are decreased after REG gamma depletion in osteosarcoma cells. In conclusion, REG gamma may be involved in the proliferation of osteosarcoma and serve as a novel therapeutic target in patients with osteosarcoma.