Na+/K+-ATPase α1 subunit, a novel therapeutic target for hepatocellular carcinoma

// Liping Zhuang 1, * , Litao Xu 1, * , Peng Wang 1 , Yan Jiang 3 , Pan Yong 3 , Chenyue Zhang 1 , Haibin Zhang 2 , Zhiqiang Meng 1 , Peiying Yang 3 1 Department of Integrative Medicine, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Collaborative Innovation Center for Cancer Medcine, Shanghai, China 2 Eastern Hepatobilliary Surgery Hospital, Second Military Medical University, Shanghai, China 3 Department of Palliative, Rehabilitation and Integrative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA * These authors have contributed equally to this work Correspondence to: Peiying Yang, e-mail: pyang@mdanderson.org Zhiqiang Meng, e-mail: mengzhq@yeah.net Keywords: Na + /K + -ATPase, subunit, hepatocellular carcinoma, oxidative stress Received: January 23, 2015 Accepted: August 07, 2015 Published: August 18, 2015 ABSTRACT We aimed to identify the expression patterns of Na + /K + -ATPase (NKA) α subunits in human hepatocellular carcinoma (HCC) samples and evaluate these subunits as potential targets for HCC treatment. The mRNA expression profiles of NKA α subunits in human HCC samples were analyzed. We found that the mRNA expression for NKA α1 subunit (ATP1A1) was higher than that for other NKA α subunits. Also, ATP1A1 gene expression was markedly higher in HCC samples than in adjacent nontumor tissue samples. Western blotting data suggested that 6 of 14 (43%) HCC samples had elevated ATP1A1 protein expression. Furthermore, knockdown of ATP1A1 expression in human HCC HepG2 and MHCC97H cells markedly reduced their proliferation in vitro and suppressed the tumorigenicity of MHCC97H cells in vivo . Downregulation of ATP1A1 expression resulted in cell-cycle arrest at G2/M phase and apoptosis in HepG2 cells as well as decreased migration in Hep3B cells. We further validated that ATP1A1 downregulation caused intracellular accumulation of reactive oxygen species. Pretreatment with N -acetyl cysteine blocked cell-growth inhibition induced by ATP1A1 downregulation. Collectively, these data suggested that targeting ATP1A1 is a novel approach to the treatment of HCC.