BACKGROUND: To investigate the effects of DNA methylation on the expression of tumor-associated genes and the cell cycle in human gastric cancer cells. METHODS: Two gastric cancer cell lines (MKN-45 and HGC-27) were treated with DNA methyltransferase (DNMT) inhibitor, 5-aza-2'-deoxycytidine (5-aza-dC). The expressions of p16INK4A, p21WAF1, p53, p73, c-Ha-ras and c-myc genes mRNA were detected by using reverse transcription PCR (RT-PCR). DNA methylation status of p16INK4A gene promoter was assayed by bisulfite modification and sequencing. The cell cycle was analyzed by using flow cytometry (FCM). RESULTS: 5-aza-dC induced the demethylation of p16INK4A gene promoter. The expression of p16INK4A mRNA was obviously up-regulated by treatment with 10 micro mol/L (MKN-45 cells) or 5 micro mol/L (HGC-27 cells) of 5-aza-dC for 24 hours. However, 5-aza-dC treatment failed to regulate the expressions of p21WAF1, p53, p73, c-Ha-ras and c-myc genes in MKN-45 and HGC-27 cells. Furthermore, 5-aza-dC induced the cell cycle arrest in G1 phase in HGC-27 cell, but not in MKN-45 cell. CONCLUSIONS: DNA methylation regulates the transcription of p16INK4A but not p21WAF1 and proto-oncogenes in human gastric cancer cell lines MKN-45 and HGC-27.
BACKGROUND: To investigate the effects of DNA methylation on the expression of tumor-associated genes and the cell cycle in humangastric cancer cells. METHODS: Two gastric cancer cell lines (MKN-45 and HGC-27) were treated with DNA methyltransferase (DNMT) inhibitor, 5-aza-2'-deoxycytidine (5-aza-dC). The expressions of p16INK4A, p21WAF1, p53, p73, c-Ha-ras and c-myc genes mRNA were detected by using reverse transcription PCR (RT-PCR). DNA methylation status of p16INK4A gene promoter was assayed by bisulfite modification and sequencing. The cell cycle was analyzed by using flow cytometry (FCM). RESULTS:5-aza-dC induced the demethylation of p16INK4A gene promoter. The expression of p16INK4A mRNA was obviously up-regulated by treatment with 10 micro mol/L (MKN-45 cells) or 5 micro mol/L (HGC-27 cells) of 5-aza-dC for 24 hours. However, 5-aza-dC treatment failed to regulate the expressions of p21WAF1, p53, p73, c-Ha-ras and c-myc genes in MKN-45 and HGC-27 cells. Furthermore, 5-aza-dC induced the cell cycle arrest in G1 phase in HGC-27 cell, but not in MKN-45 cell. CONCLUSIONS: DNA methylation regulates the transcription of p16INK4A but not p21WAF1 and proto-oncogenes in humangastric cancer cell lines MKN-45 and HGC-27.
Authors: Giovanni L Gravina; Claudio Festuccia; Francesco Marampon; Vladimir M Popov; Richard G Pestell; Bianca M Zani; Vincenzo Tombolini Journal: Mol Cancer Date: 2010-11-25 Impact factor: 27.401
Authors: Manuel Hidalgo; Jose Jorge Galan; Carmen Sáez; Eduardo Ferrero; Carolina Castilla; Reposo Ramirez-Lorca; Pablo Pelaez; Agustin Ruiz; Miguel A Japón; Jose Luis Royo Journal: BMC Cancer Date: 2008-04-21 Impact factor: 4.430