title: [Silencing hypoxia inducible factor-2α gene by small interference RNA inhibits the growth of mammosphere cells in nude mice under hypoxic microenvironment].
abstract: OBJECTIVE
  To explore the effects of silencing hypoxia inducible factor-2α (HIF-2α) by small interference RNA on the growth of mammosphere cells in nude mice under hypoxic microenvironment.
  
  
  METHODS
  The empty and interference vectors were transfected into MCF-7 cell. Then G418 was added to screen the positive cells to obtain stable cell line. The empty and interference vectors were inoculated subcutaneously into left and right back near hind limb of nude mice. The volume and weight of tumors were calculated respectively. The expressions of HIF-2α, CD44, OCT-4 and KLF-4 protein in xenograft tumor tissues were detected by Western blot.
  
  
  RESULTS
  The expression vector of HIF-2α-siRNA was successfully established. The formation of mammosphere was lowered by silencing HIF-2α gene expression. In contract to empty vector group cell, there were obvious decreases in the volumes and weights of tumors in interference group (P < 0.05). The expression of HIF-2α protein of interference group (0.42 ± 0.01) was much lower than that of the empty vector group (0.89 ± 0.03, P < 0.05), the expression of CD44 protein of interference group (0.21 ± 0.01) was much lower than the empty vector group (0.78 ± 0.03, P < 0.05), the expression of OCT-4 protein of interference group (0.42 ± 0.01)was much lower than the empty vector group (0.68 ± 0.03, P < 0.05) and the expression of KLF-4 protein of interference group (0.34 ± 0.01) was much lower than the empty vector group (0.72 ± 0.03, P < 0.05).
  
  
  CONCLUSIONS
  Silencing HIF-2α gene can effectively inhibit the growth of breast cancer stem cells in nude mice under hypoxic microenvironment. Its mechanism may be through inhibited capacity for self-renewal and proliferation of breast cancer stem cells in vivo through the down-regulated expressions of markers associated with stem cells. HIF-2α is expected to become a new target for gene therapy of breast cancer.
authors.affiliation: Department of Endocrine Surgery, First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Hong-bo
authors.initials: HB
authors.lastname: Qu
authors.forename: Yuan-ming
authors.initials: YM
authors.lastname: Fan
authors.forename: Ming-li
authors.initials: ML
authors.lastname: Han
authors.forename: Ni
authors.initials: N
authors.lastname: Zeng
authors.forename: Zhi-kun
authors.initials: ZK
authors.lastname: Zhu
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Jia
authors.initials: J
authors.lastname: Xie
authors.forename: Cheng-yi
authors.initials: CY
authors.lastname: Wu
authors.forename: Wei-xue
authors.initials: WX
authors.lastname: Tang
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D005260:Female; D005822:Genetic Vectors; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D000860:Hypoxia; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism; D061986:MCF-7 Cells; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics*; D014162:Transfection; D059016:Tumor Microenvironment; D023041:Xenograft Model Antitumor Assays; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D018960:Hyaluronan Receptors; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D050814:Octamer Transcription Factor-3; D034741:RNA, Small Interfering; D000099162:Endothelial PAS Domain-Containing Protein 1; C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse