title: Influence of different hypoxia models on metastatic potential of SGC-7901 gastric cancer cells.
abstract: Gastric cancers are one of the most common gastrointestinal tumors with proclivity to metastasis. Hypoxia is an important feature in solid tumor microenvironment; accumulating evidence suggests that chronic and repetitive exposure to hypoxia and reoxygenation seems to provide an advantage to tumor growth. However, mechanisms of intermittent hypoxia regulating gastric cancer metastatic potential remain to be elucidated. In the present study, we established the continuous and intermittent gastric cancer hypoxia models, and we compared the effects of these models on gastric cancer cell metastatic potential. Hypoxia-inducible factor-1α (HIF-1α) and hypoxia target protein/genes expression in response to different hypoxia models were analyzed by Western blot, immunofluorescence, and real-time PCR assays. Gastric cancer cell migration and invasion ability were analyzed by wound healing and Boyden chamber assay. Colony formation and tumor spheroid formation assays were used to assess the ability of self-renewal. Stem-related protein OCT4 and HIF-1α expression were also analyzed by confocal immunofluorescence in single tertiary generation spheroid. We demonstrated that the intermittent hypoxia model upregulated expression of both HIF-1α and hypoxia target protein/genes in a time-dependent manner compared with that of SGC-7901 cells cultured under normoxia. Remarkably, HIF-1α protein was more prone to being located in the nucleus of SGC-7901 cells under conditions of intermittent hypoxia. Gastric cancer cells' migration and invasion ability were significantly enhanced after hypoxic culture; moreover, intermittent hypoxia-conditioned SGC-7901 cells exhibited higher invasiveness than the continuous hypoxia-conditioned SGC-7901 cells. Gastric cancer stem/progenitor cell subpopulation was also enlarged which indicated an enhanced self-renewal ability in hypoxic cultured SGC-7901 cells. Our study emphasizes the significance of hypoxia in regulating gastric cancer cell metastasis potential. Compared with continuous hypoxia, intermittent hypoxia is a more effective and potent hypoxic stimulus. These results provide a new insight to investigate the hypoxic microenvironment within solid tumors.
authors.affiliation: Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, No. 155 North Nanjing Street, Heping District, Shenyang, Liaoning Province, 110001, China.
authors.forename: Zhi-Feng
authors.initials: ZF
authors.lastname: Miao
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Zhao
authors.forename: Zhen-Ning
authors.initials: ZN
authors.lastname: Wang
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Xu
authors.forename: Xiao-Yun
authors.initials: XY
authors.lastname: Mao
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Wu
authors.forename: Xing-Yu
authors.initials: XY
authors.lastname: Liu
authors.forename: Hao
authors.initials: H
authors.lastname: Xu
authors.forename: Yi
authors.initials: Y
authors.lastname: You
authors.forename: Hui-Mian
authors.initials: HM
authors.lastname: Xu
mesh_terms: D015687:Cell Hypoxia / Q000235:genetics*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics; D009361:Neoplasm Invasiveness / Q000235:genetics / Q000473:pathology*; D009362:Neoplasm Metastasis; D014411:Neoplastic Stem Cells / Q000473:pathology; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology*; D059016:Tumor Microenvironment / Q000235:genetics
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit
references.citation: Cell Stem Cell. 2008 Jun 5;2(6):511-2
references.pmid: 18522839
references.citation: Am J Pathol. 2011 Apr;178(4):1792-804
references.pmid: 21435459
references.citation: Ann Surg Oncol. 2007 Oct;14(10):2702-13
references.pmid: 17653801
references.citation: BMC Cancer. 2011 May 12;11:167
references.pmid: 21569415
references.citation: J Clin Oncol. 2012 Mar 1;30(7):701-8
references.pmid: 22271486
references.citation: Breast Cancer Res. 2012 Jan 07;14(1):R6
references.pmid: 22225988
references.citation: Cancer Lett. 2013 Sep 10;338(1):110-9
references.pmid: 23583679
references.citation: Oncogene. 2011 Apr 7;30(14):1693-705
references.pmid: 21132002
references.citation: Stem Cells. 2008 Jul;26(7):1818-30
references.pmid: 18467664
references.citation: Breast Cancer Res. 2010;12(6):R94
references.pmid: 21067584
references.citation: Br J Cancer. 2009 Mar 10;100(5):772-81
references.pmid: 19223895
references.citation: Cancers (Basel). 2013 Jan 10;5(1):15-26
references.pmid: 24216696
references.citation: PLoS One. 2012;7(2):e30905
references.pmid: 22363512
references.citation: J Cancer Res Clin Oncol. 2013 Oct;139(10):1721-34
references.pmid: 23990014
references.citation: Nat Med. 2003 Jun;9(6):685-93
references.pmid: 12778167
references.citation: J Cancer Res Clin Oncol. 2013 Aug;139(8):1383-9
references.pmid: 23708301
references.citation: Cell. 2008 May 16;133(4):704-15
references.pmid: 18485877
references.citation: Oncogene. 2013 Aug 1;32(31):3569-76
references.pmid: 23160373
references.citation: Cancer Treat Rev. 2014 Feb;40(1):12-21
references.pmid: 24007940
references.citation: Nat Rev Cancer. 2002 Jan;2(1):38-47
references.pmid: 11902584
references.citation: Int J Oncol. 2012 Oct;41(4):1260-70
references.pmid: 22825389
references.citation: Gastroenterology. 2011 Oct;141(4):1167-78
references.pmid: 21839702
references.citation: Oncol Rep. 2008 Oct;20(4):803-7
references.pmid: 18813821
references.citation: Stem Cells. 2013 Mar;31(3):433-46
references.pmid: 23225703
references.citation: J Clin Invest. 2013 Sep;123(9):3664-71
references.pmid: 23999440
references.citation: Stem Cells. 2010 Nov;28(11):1918-29
references.pmid: 20827750
references.citation: Cell Stem Cell. 2010 Jan 8;6(1):25-36
references.pmid: 20085740