Silencing of synaptotagmin 7 regulates osteosarcoma cell proliferation, apoptosis, and migration.

Background. Synaptotagmin 7 (SYT7) is a component of the synaptotagmin family, which is essential in many physiological and pathological processes. In this study, we aimed to investigate the role of SYT7 in osteosarcoma. Methods. We defined the expression levels of SYT7 in osteosarcoma tissues and para-sarcoma tissues by immunohistochemistry and analyzed the possible correlation between SYT7 expression and pathological characteristics via Mann-Whitney U analysis and Spearman correlation analysis. The effects of SYT7 silencing in vitro on cell growth were assessed by MTT assay. Cell cycle and cell apoptosis were assessed by flow cytometry analysis. Wound healing assay and transwell assay were applied to assess the migration and invasion capacity. Results. The results showed that the expression levels of SYT7 were upregulated in osteosarcoma tissues compared with para-sarcoma tissues and positively correlated with the pathological characteristics of osteosarcoma. Functional experiments demonstrated that SYT7 silencing significantly inhibited cell proliferation and colony formation capacity (P<0.001), induced cell cycle arrest which increased the proportion of G2 phase and decreased the proportion of S phase, enhanced cell apoptosis (P<0.01), and limited the capacity of migration and invasion (P<0.01), compared with shCtrl group. Conclusion. The results indicated that SYT7 plays a crucial role in the development of osteosarcoma. SYT7 can be applied as a new diagnostic and therapeutic target in osteosarcoma.