title: Down-regulated γ-catenin expression is associated with tumor aggressiveness in esophageal cancer.
abstract: OBJECTIVE
  To evaluate the significance of γ-catenin in clinical pathology, cellular function and signaling mechanism in esophageal squamous cell carcinoma (ESCC).
  
  
  METHODS
  The mRNA expression of γ-catenin was detected by real-time quantitative reverse transcription-polymerase chain reaction in 95 tissue specimens and evaluated for association with the clinicopathologic characteristics and survival time of patients with ESCC. siRNAs against human γ-catenin were used to inhibit γ-catenin expression. Hanging drop aggregation assay and dispase-based dissociation assay were performed to detect the effect of γ-catenin on ESCC cell-cell adhesion. Transwell assay was performed to determine cell migration. Luciferase-based transcriptional reporter assay (TOPflash) was used to measure β-catenin-dependent transcription in cells with reduced γ-catenin expression. The expression and subcellular localizations of β-catenin and E-cadherin were examined using Western blot and immunofluorescence analysis.
  
  
  RESULTS
  γ-catenin mRNA expression was significantly associated with tumor histological grade (P = 0.017) in ESCC. Kaplan-Meier survival analysis showed that γ-catenin expression levels had an impact on the survival curve, with low γ-catenin indicating worse survival (P = 0.003). The multivariate Cox regression analysis demonstrated that γ-catenin was an independent prognostic factor for survival. Experimentally, silencing γ-catenin caused defects in cell-cell adhesion and a concomitant increase in cell migration in both KYSE150 and TE3 ESCC cells. Analysis of Wnt signaling revealed no activation event associated with γ-catenin expression. Total β-catenin and Triton X-100-insoluble β-catenin were significantly reduced in the γ-catenin-specific siRNA-transfected KYSE150 and TE3 cells, whereas Triton X-100-soluble β-catenin was not altered. Moreover, knocking down γ-catenin expression resulted in a significant decrease of E-cadherin and Triton X-100-insoluble desmocollin-2, along with reduced β-catenin and E-cadherin membrane localization in ESCC cells.
  
  
  CONCLUSIONS
  γ-catenin is a tumor suppressor in ESCC and may serve as a prognostic marker. Dysregulated expression of γ-catenin may play important roles in ESCC progression.
authors.affiliation: Wang-Kai Fang, Wei Gu, Jian-Yi Wu, En-Min Li, Department of Biochemistry and Molecular Biology, The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, Guangdong Province, China.
authors.forename: Wang-Kai
authors.initials: WK
authors.lastname: Fang
authors.affiliation: Wang-Kai Fang, Wei Gu, Jian-Yi Wu, En-Min Li, Department of Biochemistry and Molecular Biology, The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, Guangdong Province, China.
authors.forename: Lian-Di
authors.initials: LD
authors.lastname: Liao
authors.affiliation: Wang-Kai Fang, Wei Gu, Jian-Yi Wu, En-Min Li, Department of Biochemistry and Molecular Biology, The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, Guangdong Province, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Gu
authors.affiliation: Wang-Kai Fang, Wei Gu, Jian-Yi Wu, En-Min Li, Department of Biochemistry and Molecular Biology, The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, Guangdong Province, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
authors.affiliation: Wang-Kai Fang, Wei Gu, Jian-Yi Wu, En-Min Li, Department of Biochemistry and Molecular Biology, The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, Guangdong Province, China.
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Wu
authors.affiliation: Wang-Kai Fang, Wei Gu, Jian-Yi Wu, En-Min Li, Department of Biochemistry and Molecular Biology, The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, Guangdong Province, China.
authors.forename: Jian-Yi
authors.initials: JY
authors.lastname: Wu
authors.affiliation: Wang-Kai Fang, Wei Gu, Jian-Yi Wu, En-Min Li, Department of Biochemistry and Molecular Biology, The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, Guangdong Province, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Shen
authors.affiliation: Wang-Kai Fang, Wei Gu, Jian-Yi Wu, En-Min Li, Department of Biochemistry and Molecular Biology, The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, Guangdong Province, China.
authors.forename: Li-Yan
authors.initials: LY
authors.lastname: Xu
authors.affiliation: Wang-Kai Fang, Wei Gu, Jian-Yi Wu, En-Min Li, Department of Biochemistry and Molecular Biology, The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, Guangdong Province, China.
authors.forename: En-Min
authors.initials: EM
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000401:mortality; D002448:Cell Adhesion; D002465:Cell Movement; D051187:Desmocollins / Q000378:metabolism; D051180:Desmoplakins / Q000378:metabolism*; D018450:Disease Progression; D004938:Esophageal Neoplasms / Q000378:metabolism* / Q000401:mortality; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D016016:Proportional Hazards Models; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D051185:gamma Catenin
chemical_list: C081561:DSC2 protein, human; D051187:Desmocollins; D051180:Desmoplakins; C495292:JUP protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051185:gamma Catenin
keywords: Cell migration; Cell-cell adhesion; Esophageal squamous cell carcinoma; Independent prognostic factor; γ-catenin