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Objective To discuss the regulatory effect of 5-aza-2 ,-deoxycytidine on P16 and MGMT in cervical cancer cells. Methods After four kinds of cervical cancer cells (HeLa, SiHa, C33A and CaSki) were treated with 5-Aza-dC , MSP was used to detect the methylation variation of P16 and MGMT , and fluorogenic quantitative PCR and Western blot were employed for determination of P16 and MGMT expression. MTT and Annexin V-FITC/PI double staining were adopted for detection of cell proliferation and apoptosis. Results Both P16 and MGMT exhibited methylation in four kinds of cervical cancer cells , and after treatment with 5-Aza-dC ,their methylation levels were reversed. 5-Aza-dC was able to inhibit p16 and MGMT expression in the cervical cancer cells, and can also suppress cell proliferation and promote apoptosis. Conclusions Although methylation of P16 and MGMT are present in cervical cancer cells, their expression level was still high. Therefore, regulation of P16 and MGMT expression may be affected by other factors. 5-Aza-dC can suppress the growth of cervical cancer cells. Although 5-Aza-dC reverse the methylation levels of P16 and MGMT, it inhibits their gene expression. More experiments are needed to verify the hidden reasons and mechanisms.
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Objective:To investigate the effects of 5-aza-2′deoxycytidine(5-aza-dC),a DNA methyltransferase (DNMT)inhibitor, on the methylation status of the RECK gene and the invasion of salivary adenoid cystic carcinoma cell lines.Methods:Methylation-specific PCR,Western blot analysis and quantitative real-time PCR were used to investigate the methylation status of RECK gene and the expression of RECK mRNA and protein in SACC cell lines.The invasive ability of SACC cells was examined by transwell assay. Results:Promoter methylation was only found in ACC-Mcell line and not in ACC-2 cell line.Treatment of ACC-Mcells with 5-aza-dC partially reversed the hypermethylation status of the RECK gene and significantly enhanced the expression level of mRNA and pro-tein of RECK,suppressed ACC-Mcell invasive ability.Conclusion:5-aza-dC can inhibit ACC-Mcell invasion by reversal of hyperm-ethylation status of RECK gene.
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Objective To investigate the effects of 5-aza-2'-deoxycytidine (5-Aza-dC) alone or combined with trichostatin A(TSA) on cell proliferation, promoter methylation and mRNA expression level of PDX-1 gene in pancreatic β cells induced by high glucose toxicity. Method NIT-1 cells were treated in vitro by high glucose (33.3 mmol/L), then divided into five groups, control group, HG grpup, 5-Aza-dC treatment group, TSA interfere group and 5-Aza-dC + TSA group. Proliferation of NIT-1 cells, insulin secretion, promoter methylation and mRNA expression of PDX-1 gene were detected respectively. Results 5-Aza-dC and TSA alone or in combination could promote cell proliferation and recover insulin secretion in NIT-1 cells , could also reduce PDX-1 gene methylation and enhance expression of PDX-1 mRNA. Compared with single-treatment group , combined group was significantly different (all P < 0.05). Conclusion 5-Aza-dC and TSA could activate the expression of PDX-1 and, then recover insulin secretion in NIT-1 cells induced by high glucose. Combination of them had synergistic effect.
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ObjectivesTo investigate the effects of 5-aza-2-deoxycytidine(5-Aza-dC),a methylation inhibitor,on the expression and methylation of tissue factor pathway Inhibitor (TFPI-2) gene in PANC1 cell line of pancreatic cancer.MethodsPANC1 cell lines were treated with different dosages of 5-Aza-dC ( 1× 10-7,5 × 10-7,1× 10 -6 mol/L).The status of TFPI-2 methylafion and expressions of TFPI-2 mRNA and protein were determined by MSP,RT-PCR,and Western blot.Results TFPI-2 gene CpG island was completely methylated,and there was no expression of TFPI-2 mRNA and protein without 5-Aza-dC treatment.After treatment with different dosages of 5-Aza-dC( 1 × 10-7,5 × 10 -7,1 × 10-6 mol/L),TFPI-2 gene CpG hypermethylation was reversed from incomplete methylated to complete non-methylated.The relative expressions of TFPI-2 mRNA were 0.211± 0.087,O.327 ± 0.068,0.609 ± 0.017; and the relative expressions of TFPI-2 protein were O.429 ± O.121,O.675 ± O.044,1.132 ± O.124 in a dose-dependent manner ( P ＜0.05 ).ConclusionsThe hypermethylatien of promoter region may be the primary reason for TFPI-2 gene expression down-rogtdation and inactivation.5-Aza-dC may reverse the hypermethylation of TFPI-2 gene,and induce the m-expression of TFPI-2 mRNA and protein.
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Objective To investigate the expression and methylation status of HOXA7 gene in human pancreatic cancer cell lines, and to explore the relationship between them.Methods HOXA7 mRNA expression of human pancreatic cancer cell lines BxPC3, CFPAC1, PANC1 and SW1990was detected by RT PCR.Bisulfite sequencing PCR (BSP) and combined bisulfite restriction analysis (COBRA) was used to test promoter methylation status.All the cell lines were treated by 5-aza-2-deoxycytidine (5-aza-dC), and HOXA7mRNA expression, methylation status was detected before and after this treatment.Results HOXA7 mRNA was expressed in BxPC3, CFPAC1 and SW1990, while there was no expression of HOXA7 mRNA in PANC1.HOXA7 promoter methylation rates of CFPAC1, BxPC3, PANC1 and SW1990 were 93.16%, 90.65%,90.09% ,52.30%.HOXA7 promoter methylation rate of SW1990 was significantly lower than those in other 3cell lines ( P ＜0.01 ).After 5-aza-dC treatment, HOXA7 mRNA of PANC1 was expressed again, and HOXA7mRNA of BxPC3 was increasingly expressed;while the expression of HOXA7 mRNA in CFPAC1 and SW1990was not significantly changed after 5-aza-dC treatment.Conclusions The expression of HOXA7 mRNA in BxPC3 and PANC1 was closely correlated with promoter hypermethylation, while there was no obvious relation in CFPAC 1 and SW1990.