Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0476089 (endometrial cancer)
 11,379 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is well known that the histone deacetylase (HDAC) inhibitor trichostatin A (TSA) acts synergistically with the DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (ADC) to reactivate DNA methylation-silenced genes. Moreover, in several studies, TSA was capable of inducing DNA demethylation even in the absence of ADC. Here we describe a mechanism by which HDAC inhibitors affect DNA methylation through their regulation on DNMT3B, a methyltransferase responsible for de novo DNA methylation. Using quantitative real-time PCR and Western blot analysis, we show that TSA down-regulates DNMT3B mRNA and protein expression in human endometrial cancer cells. This decrease in DNMT3B mRNA results in a significant reduction in de novo methylation activities. Further experiments indicated that TSA decreases DNMT3B mRNA stability and reduces its half-life from approximately 4 to 2.5 hours. We established that protein synthesis is required for posttranscriptional regulation, suggesting the involvement of an RNase and/or key mRNA stabilization factor(s) controlling the DNMT3B mRNA stability. Therefore, TSA may not only modify histone acetylation, but also potentially alter DNA methylation. Since the HDAC inhibitors are frequently used in epigenetic studies and are considered to be promising anticancer drugs, these new findings will have implications in both laboratory and clinical settings.
 ...
PMID:Histone deacetylase inhibitors decrease DNA methyltransferase-3B messenger RNA stability and down-regulate de novo DNA methyltransferase activity in human endometrial cells. 1580 66

It is well-known that exposure to unopposed estrogen is considered as an important risk factor for endometrial cancer. Recent studies have shown that over-expression of DNA methyltransferases (DNMTs) are involved in the development of endometrial cancer. Therefore, the present study was undertaken to elucidate the impact of estrogen on the expression of DNMTs in endometrial cancer. Ishikawa cell line was used. Flow cytometry analysis demonstrated that 17 beta-estradiol (E(2)) enhanced the cell proliferation with a peak at 10(-8) M. Over-expression of DNMT3B treated with E(2) was confirmed by real-time PCR and western blotting analysis. Furthermore, the up-regulation of DNMT3B expression induced by E(2) was suppressed by the addition of ICI182780. However, we did not observe changes in the expression of DNMT1. Our study suggests that estrogen up-regulating the expression of DNMT3B in an ER-dependent pathway may be a possible mechanism for estrogen facilitates the malignant transformation of endometrial cancer cells.
 ...
PMID:Estrogen regulates DNA methyltransferase 3B expression in Ishikawa endometrial adenocarcinoma cells. 1910 73

The aim of our study was to evaluate the effects of 5-aza-2'-deoxycytidine (5-azadC) on cell growth inhibition, cell cycle arrest, apoptosis as well as the expression levels of hMLH1 and DNMT3B in human endometrial cancer cell lines. Ishikawa, HHUA, and KLE cell lines were used. After treatment with 5-azadC, cells were measured by MTT to detect the growth inhibition. Flow cytometry analysis was used to evaluate the cell cycle distribution and apoptosis effect. The expression of hMLH1 and DNMT3B was performed by real-time PCR and Western blotting analysis. The methylation status of the hMLH1 gene was monitored by methylation-specific PCR. We confirmed that 5-azadC treatment resulted in growth inhibition, G(2) arrest, and cell apoptosis in human endometrial cancer cell lines. Furthermore, the data obtained by real-time PCR and Western blotting analysis demonstrated that the expression of hMLH1 was up-regulated by 5-azadC treatment in Ishikawa cells, accompanied by down-regulation of DNMT3B expression, when 5-azadC led to cell inhibition, G(2)/M arrest, and apoptosis. Our results suggested that 5-azadC is a potent inhibitor of DNA methyltransferase 3B and induces apoptosis in Ishikawa cells with the up-regulation of hMLH1.
 ...
PMID:5-Aza-2'-deoxycytidine is a potent inhibitor of DNA methyltransferase 3B and induces apoptosis in human endometrial cancer cell lines with the up-regulation of hMLH1. 1930 77