Promoter CpG Islands Methylation Of Tissue Inhibitor Of Metalloproteinases 3 Gene In Meningiomas

Partâ… Study of correlativity between the TIMP-3 expression and the biological characters in meningiomasObjective To explore the relationship between the expression of tissue inhibitor of metalloproteinase 3(TIMP-3)and the biological characters of meningiomas.Methods The expression of tissue inhibitor of metalloproteinase 3 was detected by immunohistochemistry methods in tumor specimens of 80 patients. The specimens were classified according to tumor biological characters.Results The expression of TIMP-3 was lower in non-invasive meningiomas than in invasive group (p<0.05). There is a significant difference in the distribution of TIMP-3 protein between WHOâ… group and WHOâ…¡â…¢group (p<0.05).The expression of Ki-67 correlated with the WHO histological grades(p<0.05),and had no significant difference between non-invasive and invasive groups (p>0.05).Conclusions The expression of TIMP-3 protein was related to the biological characters of meningiomas.TIMP-3 could be a novel tumor suppression gene of meningiomas. Partâ…¡The analysis of promoter CpG islands methylation of tissue inhibitor of metalloproteinases 3 gene in meningiomasObjective To analyze the relations among the aberrant methylation of the promoter CpG islands of tissue inhibitor of metalloproteinases 3 gene,its mRNA expression,and the tumor biological characters of meningiomasMethods The methylation status of promoter CpG islands and mRNA expression of TIMP3 gene in the meningiomas of 80 patients were detected by methylation -specific PCR (MSP)and RT-PCR respectively.Results RT-PCR analysis confirmed TIMP-3 down-regulation in invasive meningiomas. The rate of TIMP-3 gene expression in non-invasive tissues was 100%,while in invasive tissues,it decreased significantly to 61.1%(11 of 18 tissues). The CpG island methylation of TIMP3 was detected in 23.3% (7 of 30)tumour tissues. The hypermethylation rates of invasive meningiomas were 33.3% (6 of 18 tissues),respectively,and there was marked difference between invasive and non-invasive tissues (P<0.01). In the 7 tumor tissues with hypermethylation of TIMP-3,only one tissue was detected the expression of TIMP-3 mRNA,indicating that there were significant association between hypermethylation and reduced TIMP-3 expression.Conclusions The hypermethylation of promoter region in CpG islands could reduce the expression of TIMP-3 gene,and it maybe a important mechanism of the invasive feature of meningiomas. Partâ…¢The effect of methylation inhibitors on meningioma cells in cultureObjective To observe the effect of 5-Aza-CdR on demethylation of TIMP-3 gene promoter in meningioma cells,and detect the change of methylation status ,protein expresson and invasion ability.Methods :Meningioma cells in culture were treated with 5-Aza-2 ?-deoxycytidine (5-Aza-CdR). Expressions of TIMP - 3 protein were detected by Western blot. TIMP-3 gene promoter methylation was detected by methylation-specific PCR (MSP). MTT colorimetric assay was performed to test the inhibition on cellular growth. Invasion ability of the cells were detected by Transwell experiments.Results :Meningioma cellular growth was inhibited by 5-Aza-CdR correlating to the dose and the treating time. After treatment with 5-Aza-CdR,methylation of TIMP-3 promoter gene was not detectable in the cells in culture. The expression of TIMP-3 protein was increased. Invasion ability of the cells were declined after treatment with 5-Aza-CdR .Conclusions 5-Aza-CdR induces demethylation in TIMP-3 promoter CpG islands,restores TIMP-3 protein expression ,and inhibits invasion ability and growth of the meningioma cells.