SGK2 promotes renal cancer progression via enhancing ERK 1/2 and AKT phosphorylation

Y. Liu, J.-B. Chen, M. Zhang, X.-L. Zhang, J.-L. Meng, J. Zhou, Z.-Y. Hao, L. Zhang, X.-B. Zu, C.-Z. Liang

Department of Urology, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China. liang_chaozhao@ahmu.edu.cn

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• Oncology

OBJECTIVE: Increasing studies reported that the serum- and glucocorticoid-inducible kinases (SGKs) contributed to the tumorigenesis of various cancer. In this article, we are aiming to explore the function of SGK2 in renal cell cancer (RCC).
PATIENTS AND METHODS: In this study, the SGK2 expression was quantified by Western blot (WB) in multiple RCC cell lines. And in vitro SGK2 knockdown and overexpression experiments were also performed. In addition, molecular function analysis was performed using FunRich software V3. The Cancer Genome Atlas (TCGA) database was retrieved to verify the association between the SGK2 expression and the prognosis of RCC patients.
RESULTS: We found that SGK2 was up-regulated in RCC tissues compared with adjacent normal tissues, and the SGK2 expression also increased in various RCC cell lines compared to that in the normal epithelial cell line HK-2. Meanwhile, the SGK2 expression was significantly associated with the survival rate of RCC patients. Functional experiments showed that silencing SGK2 expression inhibited RCC cells proliferation, migration, colony formation and invasion abilities in vitro, whereas opposite results were uncovered after overexpressing SGK2 in RCC cells. Furthermore, functional analyses showed that SGK2 related genes were associated with protein serine/threonine kinase activity, guanosine triphosphatase (GTPase) activity, guanyl-nucleotide exchange factor activity, and motor activity. Protein interaction analysis identified that growth factor receptor-bound protein 2 (GRB2), one of the most important upstream components in the growth factor signaling pathway, was significantly enriched in SGK2 related genes. In addition, the WB assay validated that SGK2 could promote the phosphorylation of ERK 1/2 and AKT.
CONCLUSIONS: Our results suggested that SGK2 promoted RCC progression by mediating the phosphorylation of extracellular regulated protein kinases (ERK) 1/2 and Protein kinase B (AKT/PKB), indicating that SGK2 might serve as a potential prognostic marker and therapeutic target for renal cancer patients.

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