KCNN4 promotes invasion and metastasis through the MAPK/ERK pathway in hepatocellular carcinoma

Hepatocellular Carcinoma (HCC) is one of the most common malignancies in the world, and is well-known for its bad prognosis. Potassium calcium-activated channel subfamily N member 4 (KCNN4) is a type of intermediate conductance calcium-activated potassium channel, and increasing evidence suggests that KCNN4 contributes to the regulation of invasion and metastasis in a number of cancers. However, its clinical significance and biological function remain unclear in the HCC disease process. In this study, the expression levels of KCNN4 in 86 HCC samples were compared with corresponding paracancerous tissues. sh-RNA was used to reduce the expression of KCNN4 in Hep3B HCC cells in vitro; this was confirmed by Real time-PCR and western blotting. Wound healing, transwell assays and high content analysis were performed to investigate the tumor-promoting characteristics of KCNN4 in Hep3B HCC cells. As results, KCNN4 expression was significantly associated with preoperative serum alpha-fetoprotein level (p=0.038) and TNM stage (p=0.039). Additionally, patients with high KCNN4 amplification in HCC tissue exhibited shorter disease-free survival, whereas there was no statistical significance between KCNN4 amplification and overall survival. Wound healing and transwell assays showed that knockdown of KCNN4 expression could reduce migration and invasion abilities of HCC cells. High content analysis result showed that down-regulated KCNN4 could inhibit the ability of HCC cell proliferation. The mitogen-activated protein kinase (MAPK) pathway is active in cell proliferation, differentiation, migration, senescence, and apoptosis. Matrix metallopeptidase 9 and extracellular signal regulated kinase 1/2 (ERK1/2) were important biomarkers of MAPK/ERK pathway, knockdown of KCNN4 reduced the expression of MMP9 and ERK1/2. These findings showed that KCNN4 promotes HCC invasion and metastasis through the MAPK/ERK pathway.