title: 7-difluoromethoxyl-5,4'-di-n-octylgenistein inhibits growth of gastric cancer cells through downregulating forkhead box M1.
abstract: OBJECTIVE
  To investigate whether the 7-difluoromethoxyl-5, 4'-di-n-octylgenistein (DFOG), a novel synthetic genistein analogue, affects the growth of gastric cancer cells and its mechanisms.
  
  
  METHODS
  A series of genistein analogues were prepared by difluoromethylation and alkylation, and human gastric cancer cell lines AGS and SGC-7901 cultured in vitro were treated with various concentrations of genistein and genistein analogues. The cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cells were incubated by DFOG at different concentrations. The growth inhibitory effects were evaluated using MTT and clonogenic assay. The distribution of the phase in cell cycle was analyzed using flow cytometric analysis with propidium iodide staining. The expression of the transcription factor forkhead box M1 (FOXM1) was analyzed by reverse transcription-polymerase chain reaction and Western blotting. The expression levels of CDK1, Cdc25B, cyclin B and p27(KIP1) protein were detected using Western blotting.
  
  
  RESULTS
  Nine of the genistein analogues had more effective antitumor activity than genistein. Among the tested analogues, DFOG possessed the strongest activity against AGS and SGC-7901 cells in vitro. DFOG significantly inhibited the cell viability and colony formation of AGS and SGC-7901 cells. Moreover, DFOG efficaciously arrested the cell cycle in G2/M phase. DFOG decreased the expression of FOXM1 and its downstream genes, such as CDK1, Cdc25B, cyclin B, and increased p27(KIP1) at protein levels. Knockdown of FOXM1 by small interfering RNA before DFOG treatment resulted in enhanced cell growth inhibition in AGS cells. Up-regulation of FOXM1 by cDNA transfection attenuated DFOG-induced cell growth inhibition in AGS cells.
  
  
  CONCLUSIONS
  DFOG inhibits the growth of human gastric cancer cells by down-regulating the FOXM1 expression.
authors.affiliation: Laboratory of Medical Engineering, Medical College, Hunan Normal University, Changsha 410013, Hunan Province, China.
authors.forename: Hong-Lin
authors.initials: HL
authors.lastname: Xiang
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Mei-Fang
authors.initials: MF
authors.lastname: Quan
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Cao
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lv
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D018076:DNA, Complementary / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects*; D000072278:Forkhead Box Protein M1; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D019833:Genistein / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D034741:RNA, Small Interfering / Q000494:pharmacology; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D014162:Transfection
chemical_list: C579741:7-difluoromethoxyl-5,4'-di-n-octylgenistein; D018076:DNA, Complementary; C107585:FOXM1 protein, human; D000072278:Forkhead Box Protein M1; D051858:Forkhead Transcription Factors; D034741:RNA, Small Interfering; D019833:Genistein