[Impacts of hypoxia on the features and chemoresistance of cancer stem cells in Hep-2 cells and underlying mechanism].
OBJECTIVE
To investigate the effects of hypoxia on the features and chemoresistance of cancer stem cells in Hep-2 cells and underlying mechanism.


METHODS
The shRNA interference recombinant plasmid targeting HIF-1α was synthesized and transfected into Hep-2 cells. The HIF-1α knockdown Hep-2 cells were established after clonal selection and the expression of HIF-1α was measured. The cellular features including proliferation, clonal formation, cell cycle, apoptosis and CD133 phenotype were measured in Hep-2 cells cultured under hypoxic condition in vitro. CD133+ cells were sorted from Hep-2 cells with flow cytometry. Clonal formation test and cisplatin treatment were carried out, and the expressions of related genes (Oct-4, suvivin and p53) in CD133+ cells were measured.


RESULTS
HIF-1α knockdown Hep-2 cells was successfully established, as evidenced by the reduced mRNA and protein expressions of HIF-1α. The Hep-2 cells cultured under hypoxic microenvironment showed higher proliferation and clonal formation activity, cell cycle arrest in G0/G1, lower apoptosis, up-regulated CD133, however the effects of hypoxia reduced in HIF-1α knockdown Hep-2 cells. CD133+ cells were successfully sorted from Hep-2 cells, and the CD133+ cells showed increased clonal formation activity and cisplatin treatment resistance in hypoxia. Also the effects of hypoxia on CD133+ cells decreased with HIF-1α knockdown, showing down-regulated Oct-4 and survivin and up-regulated p53.


CONCLUSIONS
Hypoixa can induce the features of cancer stem cells in Hep-2 cells and increase proliferation, differentiation and chemoresistant ability of CD133+ cells, which might be correlated with the changes in expressions of HIF-1α and related genes regulated by HIF-1α.
Department of Otorhinolaryngology, Hebei Medical University, Shijiazhuang 050017, China.
Yong-tao
YT
Qu
Xiao-ming
XM
Li
Ou
O
Xu
Mao-xin
MX
Wang
Xiu-ying
XY
Lu
D017209:Apoptosis; D002294:Carcinoma, Squamous Cell / Q000473:pathology; D002453:Cell Cycle; D002454:Cell Differentiation; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019008:Drug Resistance, Neoplasm; D055785:Gene Knockdown Techniques; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics*; D007822:Laryngeal Neoplasms / Q000473:pathology; D014411:Neoplastic Stem Cells / Q000166:cytology*; D034741:RNA, Small Interfering / Q000235:genetics
C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D034741:RNA, Small Interfering