SIRT1 overexpression protects non-small cell lung cancer cells against osteopontin-induced epithelial-mesenchymal transition by suppressing NF-κB signaling

Abstract

Xuejiao Li,1 Zhongxiu Jiang,2 Xiangmin Li,2 Xiaoye Zhang2 1The Second Clinical College, China Medical University, 2Fourth Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, People’s Republic of China Abstract: Osteopontin (OPN) is a promoter for tumor progression. It has been reported to promote non-small cell lung cancer (NSCLC) progression via the activation of nuclear factor-κB (NF-κB) signaling. As the increased acetylation of NF-κB p65 is linked to NF-κB activation, the regulation of NF-κB p65 acetylation could be a potential treatment target for OPN-induced NSCLC progression. Sirtuin 1 (SIRT1) is a deacetylase, and the role of SIRT1 in tumor progression is still controversial. The effect and mechanism of SIRT1 on OPN-induced tumor progression remains unknown. The results presented in this research demonstrated that OPN inhibited SIRT1 expression and promoted NF-κB p65 acetylation in NSCLC cell lines (A549 and NCI-H358). In this article, overexpression of SIRT1 was induced by infection of SIRT1-overexpressing lentiviral vectors. The overexpression of SIRT1 protected NSCLC cells against OPN-induced NF-κB p65 acetylation and epithelial-mesenchymal transition (EMT), as indicated by the reduction of OPN-induced changes in the expression levels of EMT-related markers and cellular morphology. Furthermore, SIRT1 overexpression significantly attenuated OPN-induced cell proliferation, migration and invasion. Moreover, overexpression of SIRT1 inhibited OPN-induced NF-κB activation. As OPN induced NSCLC cell EMT through activation of NF-κB signaling, OPN-induced SIRT1 downregulation may play an important role in NSCLC cell EMT via NF-κB signaling. The results suggest that SIRT1 could be a tumor suppressor to attenuate OPN-induced NSCLC progression through the regulation of NF-κB signaling. Keywords: OPN, SIRT1, EMT, NF-κB, NSCLC

Keywords

• OPN
• SIRT1
• EMT
• NF-κB
• NSCLC