title: hTERT promotes the invasion of gastric cancer cells by enhancing FOXO3a ubiquitination and subsequent ITGB1 upregulation.
abstract: Human telomerase reverse transcriptase (hTERT) plays an important role in cancer invasion, but the relevant mechanism is not well known. This study aims to investigate the role and mechanism of hTERT in gastric cancer metastasis.
  
  
  
  Proteomics analysis, qPCR and western blotting were used to screen for hTERT-regulated candidate molecules in gastric cancer invasion. Chromatin immunoprecipitation (ChIP) qPCR was performed to identify the binding sites of hTERT at the regulatory region of the integrin β1 (ITGB1) gene. ChIP assays were further applied to elucidate the transcription factors that bound to the regulatory region. The interactions between hTERT and the transcription factors were tested by co-immunoprecipitation (Co-IP) and glutathione S-transferase (GST) pull-down experiments. Moreover, the revealed pathway was verified in tumour-bearing nude mice and human gastric cancer tissues.
  
  
  
  ITGB1 was identified as a downstream gene of hTERT, and there were two hTERT-binding regions within this gene. hTERT alleviated the binding of forkhead box O3 (FOXO3a) to FOXO3a binding element (+9972∼+9978), but it enhanced the binding of forkhead box M1 (FOXM1) to FOXM1 binding element (-1104∼-1109) in ITGB1 gene. Importantly, FOXO3a played a major role in hTERT-induced ITGB1 expression, and the hTERT/murine double minute 2 (MDM2) complex promoted the ubiquitin-mediated degradation of FOXO3a. Moreover, hTERT increased ITGB1 expression in xenograft gastric cancer, and the level of hTERT was positively correlated with that of ITGB1 in human gastric cancer tissues.
  
  
  
  The hTERT/MDM2-FOXO3a-ITGB1 pathway markedly contributes to hTERT-promoted gastric cancer invasion, suggesting that this pathway might be a novel target for the prevention and treatment of gastric cancer metastasis.
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Changjiang
authors.initials: C
authors.lastname: Hu
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.
authors.forename: Zhenghong
authors.initials: Z
authors.lastname: Ni
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Bo-Sheng
authors.initials: BS
authors.lastname: Li
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yong
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Zhang
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Meng-Meng
authors.initials: MM
authors.lastname: Jie
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.|Division of Gastroenterology, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Dong
authors.affiliation: Department of Pharmaceutical Sciences, Center for Pharmacogenetics, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.
authors.forename: Fengtian
authors.initials: F
authors.lastname: He
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Shi-Ming
authors.initials: SM
authors.lastname: Yang
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement; D005260:Female; D000072278:Forkhead Box Protein M1 / Q000378:metabolism; D000071316:Forkhead Box Protein O3 / Q000378:metabolism*; D006801:Humans; D019012:Integrin beta1 / Q000235:genetics* / Q000378:metabolism*; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000556:secondary; D008207:Lymphatic Metastasis; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D015996:Survival Rate; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination; D015854:Up-Regulation
chemical_list: C107585:FOXM1 protein, human; C499517:FOXO3 protein, human; D000072278:Forkhead Box Protein M1; D000071316:Forkhead Box Protein O3; C474033:FoxO3 protein, mouse; D019012:Integrin beta1; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D019098:Telomerase
keywords: EXTRACELLULAR MATRIX; GASTRIC CANCER; MOLECULAR CARCINOGENESIS; MOLECULAR MECHANISMS; MOLECULAR ONCOLOGY