title: Increased expression of EIF5A2, via hypoxia or gene amplification, contributes to metastasis and angiogenesis of esophageal squamous cell carcinoma.
abstract: OBJECTIVE
  Solid tumors often become hypoxic, leading to activation of hypoxia-response genes. We investigated the effects of overexpression of the hypoxia response genes eIF5A2 in esophageal squamous cell carcinoma (ESCC).
  
  
  METHODS
  We used quantitative real-time polymerase chain reaction and immunohistochemistry analyses to compare expression of eIF5A2 between paired ESCC samples and nontumor esophageal tissues, and fluorescence in situ hybridization to detect gene copy-number alterations. Luciferase reporter and chromatin immunoprecipitation assays were used to study interactions between eIF5A2 and hypoxia-inducible factor-1α (HIF1α). We determined the effects of eIF5A2 overexpression and knockdown in ESCC cell lines and growth of ESCC xenograft tumors in nude mice.
  
  
  RESULTS
  Levels of eIF5A2 messenger RNA and protein were increased in >40% of ESCC samples compared with matched nontumor tissues, along with levels of HIF1α and vascular endothelial growth factor. Increased levels of EIF5A2 were significantly associated with ESCC metastasis to lymph nodes (P < .001) and tissue invasion (P = .037), and shorter survival times of patients (P < .001). Amplification of eIF5A2 was detected in 35.14% of ESCC samples that overexpressed eIF5A2. Hypoxia increased expression of eIF5A2 4- to 8-fold in ESCC cell lines; we observed bidirectional regulation between eIF5A2 and HIF1α. Transient transfection of ESCC cell lines with eIF5A2 increased their migratory and invasive abilities and markers of the epithelial to mesenchymal transition, and eIF5A2 knockdown or HIFα inhibition reduced these. In mice, xenograft tumors grown from ESCC cells that expressed eIF5A2 formed tumors more rapidly than cells that expressed only vector (controls); they also expressed higher levels of HIF1α and vascular endothelial growth factor, and formed more microvessels than controls. Knockdown of eIF5A2 in ESCC cells with interfering RNAs reduced their growth as xenograft tumors in mice, particularly when mice were given docetaxel or cisplatin.
  
  
  CONCLUSIONS
  eIF5A2 is overexpressed by gene amplification or hypoxia in ESCCs, and associated with up-regulation of HIF1α, metastasis, and shorter survival times of patients. Increased expression of eIF5A2 increases metastasis and angiogenesis in ESCC via the HIF1α-mediated signaling pathway.
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China. Electronic address: liy6@mail.sysu.edu.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China; Department of Clinical Oncology, The University of Hong Kong, Hong Kong, China.
authors.forename: Li
authors.initials: L
authors.lastname: Fu
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Jian-Biao
authors.initials: JB
authors.lastname: Li
authors.affiliation: Department of Clinical Oncology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, China.
authors.forename: Yanru
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Ting-ting
authors.initials: TT
authors.lastname: Zeng
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Zhao-Lei
authors.initials: ZL
authors.lastname: Zeng
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Jinna
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Clinical Oncology, The University of Hong Kong, Hong Kong, China.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Cao
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Xiaojiao
authors.initials: X
authors.lastname: Ban
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Chaonan
authors.initials: C
authors.lastname: Qian
authors.affiliation: Hong Kong Baptist University, Hong Kong, China.
authors.forename: Zongwei
authors.initials: Z
authors.lastname: Cai
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Xie
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Huang
authors.affiliation: Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China; Department of Clinical Oncology, The University of Hong Kong, Hong Kong, China. Electronic address: xyguan@hkucc.hku.hk.
authors.forename: Xin-Yuan
authors.initials: XY
authors.lastname: Guan
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000098:blood supply / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000556:secondary; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002465:Cell Movement; D002945:Cisplatin / Q000494:pharmacology; D000077143:Docetaxel; D058750:Epithelial-Mesenchymal Transition; D004938:Esophageal Neoplasms / Q000098:blood supply / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D005260:Female; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D053208:Kaplan-Meier Estimate; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009389:Neovascularization, Pathologic; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D016016:Proportional Hazards Models; D011485:Protein Binding; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D043823:Taxoids / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D000970:Antineoplastic Agents; D002945:Cisplatin; D000077143:Docetaxel; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D010448:Peptide Initiation Factors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D043823:Taxoids; D042461:Vascular Endothelial Growth Factor A; D000097574:Eukaryotic Translation Initiation Factor 5A; C497442:HIF1A protein, human; C467484:VEGFA protein, human
keywords: EMT; Gene Regulation; Oncogene; Oxygen