The Relationship Of Activin A Action On Regulating Proliferation Of Tumor Cells And Expression Of DNA Methyltransferases(DNMTs)

Background:As one the most important modification pathway of epigenetics, methylation of DNA is playing a significant role of cancer initiation and development. As inspecific case, DNMT significantly affect tumor development. DNMT gens are up-regulated in certain tumor cells and affect cell apoptosis. Activin A, the family oftransforming growth factor TGF-β, is a multifunctional growth and differentiationfactor, and plays an important role in many aspects in the regulation of cellproliferation and apoptosis. However, the research whether the activin A can regulatethe DNMTs function to control cell apoptosis has not yet been relevant reports.Research Objectives: To investigate whether activin A regulates cell apoptosis in aDNMT-dependent manner, we discuss the difference of DNMTs gene expressionsbetween tumor cells and normal cells, also study whether have activin A anyrelevance to cancer cells.Research Methods: We detect the cells proliferation activity by MTT who weretreated the activin A for different times (24h,48h,72h), we used Giemsa staining aftertreatment with activin A cell morphological changes, we used RT-PCR to detect themRNA expressions of NS-1cell apoptosis related gene and DNMT, Flow cytometrywas used to detect the proliferation and apoptosis of NS-1cellsResearch Results: Through detecting DNMTs expression in types of nineteen mousecells and eighteen types of human cells, Our experiments demonstratedthe difference in DNMTs mRNA expression profiles between tumor cells and normalcells. Giemsa staining assay showed that activin A induced different morphologicchanges of different cancer cells. MTT results showed thatthere existed a significant difference in cell growth rate among cancer cells. Next,mouse myeloma NS-1cells were treated with different concentration of activin A (2.5ng/ml,5ng/ml、10ng/ml、20ng/ml)for different times (24h,48h,72h). MTT assaysindicated that activin A efficiently inhibited NS-1cells proliferation, the effect of ActA is dose-and time-dependent. By flow cytometry to detect cell proliferation is foundthat activin A can inhibit proliferation of NS-1.Compared with controls, activin Adown-regulated the mRNA expression of DNMT for12h. Meanwhile, activin Ainduced the expression of apoptosis-related gene of Caspase3/8/12and Chop. Therewas no obvious changes in the expression of Bcl-2、Bax、P53and p21, comparedwith controls. Flow cytometry showed that activin A increased cell apoptosis ratiocompared with controls at24h. Giemsa staining assay showed that differentmorphologic changes exsit between activin A treated groups and control group.Conclusion: There is a significant relevance between the expression of DNMTs andthe occurrence and development of cancer.What’s more, activin A may down-regulatethe expression of DNMTs and inhibited NS-1cell proliferation, which can also inducecell apoptosis by ER stress-mediated apoptosis Pathway.