Epigenetic alterations have emerged as an important mechanism involved in tumorigenesis. The epigenetic impact of DNA methylation in various types of human cancer is not completely understood. Previously, we observed melatonin-induced differential expression of miRNA and miRNA-related genes in human breast cancer cell lines that indicated an anticancer effect of melatonin. In this report, we further characterized epigenetic changes in melatonin-exposed MCF-7 cells through the analysis of DNA methylation profiles in breast cancer cells to provide new insights into the potential mechanisms of the anticancer effect of melatonin. Microarray-based DNA methylation and gene expression profiling were carried out using human breast cancer cell lines. We further identified a number of mRNAs whose expression levels show an inverse correlation with DNA methylation levels. The mRNA expression levels and methylation status of candidate genes in melatonin-exposed cells were confirmed by real-time quantitative PCR and bisulfite PCR. This approach led to the detection of cancer-related genes, which were oncogenic genes, including EGR3 and POU4F2/Brn-3b were down-regulated, while the tumor suppressor gene, GPC3, was up-regulated by 1 nm melatonin-treated MCF-7 cells. Our results provide detailed insights into the DNA methylation patterns induced by melatonin and suggest a potential mechanism of the anticancer effect of aberrant DNA methylation in melatonin-treated breast cancer cells.
Presently, it is important to address the harmful effects of environmental chemicals on living organisms. The toxic effects of bisphenol A (BPA), one of the endocrine disruption chemicals (EDCs), have been documented in many studies since the 1930s. However, BPA has continued to be used to make polycarbonate plastic, etc. Therefore, it is necessary to conduct toxicogenomic studies to assess the harmful effects of BPA. In this study, microarray technology was used to study the harmful effects format the genomic level. We used two types of microarray chips to study of the relationship between gene and miRNA expression profiles, the Agilent mouse genome 4 44 K array for gene expression profiling and the Agilent mouse miRNA v13 for miRNA expression profiling. As a result, we identified 37 miRNAs that were 2-fold up-or down-regulated within 24 hrs than 3 hrs of BPA treat times. The gene expression patterns related to miRNAs were classified into a total of 4 groups. The first and third groups and the second and fourth groups had similar functions to each other as determined by related gene expression. In the first and third groups included overexpressed genes that were related to metabolism. The second and fourth groups included overexpressed genes that were related to reproduction. miRNA expression levels were exchanged for BPA degradation. So, genes of related metabolism were overexpressed. This result was occurred the side effect that was down-expression of reproduction. Thus, miRNAs were regulated by BPA, and gene expression was subsequently regulated by miRNAs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.