Leptin promotes proliferation and invasion of osteosarcoma cells by upregulating the expression of SIRT1

Osteosarcoma (OS) is a primary high-grade malignant bone neoplasm, and the prognosis ofOS remains poor due to early metastasis. Leptin plays an essential role in tumorigenesis, but the role of leptin in the development of OS is still not fully understood. In this study, we used a human osteosarcomaMG-63 cell line as an experimentalmodel. MG-63 cells were treated with leptin, and cell proliferation, apoptosis, adhesion, invasion, and gene expression, were evaluated. The results showed that leptin promoted proliferation, decreased adhesion, suppressed apoptosis, and promoted invasion, of MG-63 cells. Moreover, the expression of SIRT1 was upregulated in MG-63 cells exposed to leptin. Furthermore, MMP-2, 8, and 9 were significantly upregulated by SIRT1, while SIRT1 knockdown inhibited the proliferation and invasion of MG-63 cells. In conclusion, our results suggest that leptin promotes OS cell proliferation and invasion by inducing the expression of SIRT1.