Parkinson’s gene PINK1 modulates cell proliferation and autophagy in osteosarcoma

Abstract

Objective Osteosarcoma is one of the most common primary bone malignancies affecting adolescents and young adults. Although many approaches have established for osteosarcoma treatment, the survival outcome remained stagnant. PTEN-induced kinase 1 (PINK1) is a Parkinson’s disease-associated gene but was originally identified in cancer cells. However, the role of PINK1 in cancers such as osteosarcoma is unknown. Methods The expression of PINK1 was determined by qRT-PCR and Western blot immunostaining. In order to test our hypothesis, CCK-8 assay, Ki67 and clonogenic assay were performed to analyze the cell growth after transfection with PINK1-siRNA. The changes in growth related proteins (Bax, Bad, caspase-3) were detected by Western blot. Results First, we found that both mRNA and protein levels of PINK1 were upregulated in osteosarcoma tissues. CCK-8 assay and clonogenic assay showed that knockdown of PINK1 decreased SaOS2 osteosarcoma cells growth. Ki-67 immunofluorescence staining showed decreased proliferation ability in SaOS2 depleted of PINK1 compared to control cells. Further, we found that knockdown of PINK1 suppressed autophagy induction characterized by reduced ratio of LC3-Ⅱ/LC3-Ⅰ, and the protein level of Beclin-1. In addition, we found that knockdown of PINK1 resulted in increased level of cleaved caspase-3. Expressions of Bad and Bax showed the same patterns. Conclusion In conclusion, our findings revealed an important role of PINK1 in osteosarcoma and suggest that PINK1 might be a potential osteosarcoma-related therapeutic target. Key words: Osteosarcoma; PINK1; Cell growth; Autophagy