1. Sodium valproate and 5-aza-2′-deoxycytidine differentially modulate DNA demethylation in G1 phase-arrested and proliferative HeLa cells
- Author
-
Marina Amorim Rocha, Wirla Maria da Silva Cunha Tamashiro, Marina Barreto Felisbino, Maria Luiza S. Mello, Maria Silvia Viccari Gatti, and Giovana Maria Breda Veronezi
- Subjects
medicine.drug_class ,Blotting, Western ,lcsh:Medicine ,Enzyme-Linked Immunosorbent Assay ,Decitabine ,Real-Time Polymerase Chain Reaction ,Article ,HeLa ,Cell growth ,medicine ,Humans ,lcsh:Science ,Cell Proliferation ,Demethylation ,DNA methylation ,Multidisciplinary ,biology ,Chemistry ,Valproic Acid ,Histone deacetylase inhibitor ,lcsh:R ,G1 Phase ,Cell cycle ,Flow Cytometry ,biology.organism_classification ,Molecular biology ,DNA Demethylation ,DNA demethylation ,DNMT1 ,lcsh:Q ,HeLa Cells - Abstract
Sodium valproate/valproic acid (VPA), a histone deacetylase inhibitor, and 5-aza-2-deoxycytidine (5-aza-CdR), a DNA methyltransferase 1 (DNMT1) inhibitor, induce DNA demethylation in several cell types. In HeLa cells, although VPA leads to decreased DNA 5-methylcytosine (5mC) levels, the demethylation pathway involved in this effect is not fully understood. We investigated this process using flow cytometry, ELISA, immunocytochemistry, Western blotting and RT-qPCR in G1 phase-arrested and proliferative HeLa cells compared to the presumably passive demethylation promoted by 5-aza-CdR. The results revealed that VPA acts predominantly on active DNA demethylation because it induced TET2 gene and protein overexpression, decreased 5mC abundance, and increased 5-hydroxy-methylcytosine (5hmC) abundance, in both G1-arrested and proliferative cells. However, because VPA caused decreased DNMT1 gene expression levels, it may also act on the passive demethylation pathway. 5-aza-CdR attenuated DNMT1 gene expression levels but increased TET2 and 5hmC abundance in replicating cells, although it did not affect the gene expression of TETs at any stage of the cell cycle. Therefore, 5-aza-CdR may also function in the active pathway. Because VPA reduces DNA methylation levels in non-replicating HeLa cells, it could be tested as a candidate for the therapeutic reversal of DNA methylation in cells in which cell division is arrested.
- Published
- 2019