title: Rho kinase phosphorylation promotes ezrin-mediated metastasis in hepatocellular carcinoma.
abstract: During progression of hepatocellular carcinoma, multiple genetic and epigenetic alterations act to posttranslationally modulate the function of proteins that promote cancer invasion and metastasis. To define such abnormalities that contribute to liver cancer metastasis, we carried out a proteomic comparison of primary hepatocellular carcinoma and samples of intravascular thrombi from the same patient. Mass spectrometric analyses of the liver cancer samples revealed a series of acidic phospho-isotypes associated with the intravascular thrombi samples. In particular, we found that Thr567 hyperphosphorylation of the cytoskeletal protein ezrin was tightly correlated to an invasive phenotype of clinical hepatocellular carcinomas and to poor outcomes in tumor xenograft assays. Using phospho-mimicking mutants, we showed that ezrin phosphorylation at Thr567 promoted in vitro invasion by hepatocarcinoma cells. Phospho-mimicking mutant ezrinT567D, but not the nonphosphorylatable mutant ezrinT567A, stimulated formation of membrane ruffles, suggesting that Thr567 phosphorylation promotes cytoskeletal-membrane remodeling. Importantly, inhibition of Rho kinase, either by Y27632 or RNA interference, resulted in inhibition of Thr567 phosphorylation and a blockade to cell invasion, implicating Rho kinase-ezrin signaling in hepatocellular carcinoma cell invasion. Our findings suggest a strategy to reduce liver tumor metastasis by blocking Rho kinase-mediated phosphorylation of ezrin.
authors.affiliation: Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shanxi, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Guo
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.forename: Bing
authors.initials: B
authors.lastname: Wu
authors.forename: Hui
authors.initials: H
authors.lastname: Deng
authors.forename: Ti
authors.initials: T
authors.lastname: Zhou
authors.forename: Hongjun
authors.initials: H
authors.lastname: Xiang
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.forename: Xue
authors.initials: X
authors.lastname: Yu
authors.forename: Jian
authors.initials: J
authors.lastname: Liao
authors.forename: Tarsha
authors.initials: T
authors.lastname: Ward
authors.forename: Peng
authors.initials: P
authors.lastname: Xia
authors.forename: Chibuzo
authors.initials: C
authors.lastname: Emenari
authors.forename: Xia
authors.initials: X
authors.lastname: Ding
authors.forename: Winston
authors.initials: W
authors.lastname: Thompson
authors.forename: Kelong
authors.initials: K
authors.lastname: Ma
authors.forename: Jingde
authors.initials: J
authors.lastname: Zhu
authors.forename: Felix
authors.initials: F
authors.lastname: Aikhionbare
authors.forename: Kefen
authors.initials: K
authors.lastname: Dou
authors.forename: Shi-Yuan
authors.initials: SY
authors.lastname: Cheng
authors.forename: Xuebiao
authors.initials: X
authors.lastname: Yao
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D016513:Mice, SCID; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D010766:Phosphorylation; D015398:Signal Transduction / Q000502:physiology; D023041:Xenograft Model Antitumor Assays; D054460:rho-Associated Kinases / Q000378:metabolism*; D000099149:Ezrin
chemical_list: D003598:Cytoskeletal Proteins; D004791:Enzyme Inhibitors; D054460:rho-Associated Kinases; D000099149:Ezrin