title: Epigenetic modification regulates both expression of tumor-associated genes and cell cycle progressing in human colon cancer cell lines: Colo-320 and SW1116.
abstract: The aim of this study is to assess the effects of DNA methylation and histone acetylation, alone or in combination, on the expression of several tumor-associated genes and cell cycle progression in two established human colon cancer cell lines: Colo-320 and SW1116. Treatments with 5-aza-2-deoxycytidine (5-aza-dC) and trichostatin A, alone or in combination, were applied respectively. The methylation status of the CDKN2A promoter was determined by methylation-specific PCR, and the acetylated status of the histones associated with the p21WAF1 and CDKN2A genes was examined by chromatin immunoprecipitation. The expression of the CDKN2A, p21WAF1, p53, p73, APC, c-myc, c-Ki-ras and survivin genes was detected by real-time RT-PCR and RT-PCR. The cell cycle profile was established by flow cytometry. We found that along with the demethylation of the CDKN2A gene promoter in both cell lines induced by 5-aza-dC alone or in combination with TSA, the expression of both CDKN2A and APC genes increased. The treatment of TSA or sodium butyrate up-regulated the transcription of p21WAF1 significantly by inducing the acetylation of histones H4 and H3, but failed to alter the acetylation level of CDKN2A-associated histones. No changes in transcription of p53, p73, c-myc, c-Ki-ras and survivin genes were observed. In addition, TSA or sodium butyrate was shown to arrest cells at the G1 phase. However, 5-aza-dC was not able to affect the cell cycle progression. In conclusion, regulation by epigenetic modification of the transcription of tumor-associated genes and the cell cycle progression in both human colon cancer cell lines Colo-320 and SW1116 is gene-specific.
authors.affiliation: Shanghai Institute of Digestive Disease, Renji Hospital Shanghai Second Medical University, Shanghai 200001, China. jingyuanfang@yahoo.com
authors.forename: Jing Yuan
authors.initials: JY
authors.lastname: Fang
authors.forename: Ying Xuan
authors.initials: YX
authors.lastname: Chen
authors.forename: Juan
authors.initials: J
authors.lastname: Lu
authors.forename: Rong
authors.initials: R
authors.lastname: Lu
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Hong Yin
authors.initials: HY
authors.lastname: Zhu
authors.forename: Wei Qi
authors.initials: WQ
authors.lastname: Gu
authors.forename: Lun Gen
authors.initials: LG
authors.lastname: Lu
mesh_terms: D000107:Acetylation; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002087:Butyrates / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003110:Colonic Neoplasms / Q000098:blood supply / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000187:drug effects / Q000378:metabolism; D019175:DNA Methylation; D000077209:Decitabine; D015972:Gene Expression Regulation, Neoplastic; D017491:Genes, APC / Q000187:drug effects; D019942:Genes, p16 / Q000187:drug effects; D006657:Histones / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology
chemical_list: D002087:Butyrates; D006657:Histones; D006877:Hydroxamic Acids; C012589:trichostatin A; D000077209:Decitabine; D004247:DNA; D001374:Azacitidine