Discovery of NKCC1 as a potential therapeutic target to inhibit hepatocellular carcinoma cell growth and metastasis.

Yaya Zhou,Ying Jiang,Binxue Zhang,Aihua Sun,Fuchu He,Jian Zhang,Handong Wei,Ning Chen,Wei Sun,Xinxin Wang,Ning Hao,Chen Xu,Kun Dong

doi:10.18632/oncotarget.20240

Abstract

Metastasis is the essential cause for the high mortality of hepatocellular carcinoma (HCC). In order to investigate the mechanism of metastasis, and to discover therapeutic targets for HCC, the quantitative proteomic technique was applied to characterize the plasma membrane proteins of two HCC cell lines with low (MHCC97L) or high (MHCC97H) metastatic potentials. One of the plasma membrane proteins, sodium-potassium-chloride cotransporter 1 (NKCC1), was upregulated in MHCC97H cell line. Immunohistochemistry result in HCC patients showed that NKCC1 expression was associated with poor differentiation and microvascular invasion. Knockdown of NKCC1 via RNA interference reduced HCC cell proliferation and invasion abilities in vitro and in vivo, whereas over-expression of NKCC1 significantly increased HCC cell proliferation and invasion abilities in vitro and in vivo. Additionally, blocking NKCC1 activity with bumetanide attenuated the proliferation and invasion abilities of HCC cells in vitro and limited the HCC growth in vivo. Further results suggested that NKCC1 promotes the invasion ability via MMP-2 activity, and that the WNK1/OSR1/NKCC1 signal pathway might play roles in HCC metastasis. For the first time, our study demonstrated that NKCC1 plays a role in HCC metastasis, and could be served as a potential target to inhibit HCC cell growth and metastasis.

Highlights

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide [1]
The electron micrographs showed that the cell and the subsequently isolated plasma membrane were successfully coated by the silica pellicle, whereas the control cells remained uncoated (Figure 1B)
hepatocellular carcinoma (HCC) metastasis is closely related to multiple factors, such as cancer cell adhesion and motility, extracellular matrix degradation, body immunity, tumor angiogenesis, and other processes

Summary

INTRODUCTION

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide [1]. Metastasis is the main cause for poor prognosis and high fatality rates in HCC [2]. Multiple functional receptors and ion channels have been www.impactjournals.com/oncotarget approved as valid drug targets for cancer therapy [12,13,14], such as growth factor receptors [12, 15], cytokine receptors [16], potassium channels [14, 17] and so on. Despite their importance in cancer research, the analysis of plasma membrane proteins remains challenging due to difficulties in their isolation or enrichment. Our study suggested that NKCC1 might be a potential therapeutic target to inhibit HCC growth and metastasis

RESULTS

DISCUSSION

Experimental procedures