Title:Sodium Valproate Modulates the Methylation Status of Lysine Residues 4,
9 and 27 in Histone H3 of HeLa Cells
Volume: 16
Author(s): Marina Amorim Rocha, Benedicto de Campos Vidal and Maria Luiza Silveira Mello*
Affiliation:
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), 13083-862 Campinas,
SP, Brazil
Keywords:
Epigenetics, HeLa cells, histone methylation, histone demethylase, EZH2, VPA.
Abstract:
Background: Valproic acid/sodium valproate (VPA), a well-known anti-epileptic agent, inhibits
histone deacetylases, induces histone hyperacetylation, promotes DNA demethylation, and affects
the histone methylation status in some cell models. Histone methylation profiles have been described as
potential markers for cervical cancer prognosis. However, histone methylation markers that can be studied
in a cervical cancer cell line, like HeLa cells, have not been investigated following treatment with VPA.
Methods: In this study, the effect of 0.5 mM and 2.0 mM VPA for 24 h on H3K4me2/me3, H3K9me/me2
and H3K27me/me3 signals as well as on KMT2D, EZH2, and KDM3A gene expression was investigated
using confocal microscopy, Western blotting, and RT-PCR. Histone methylation changes were also investigated
by Fourier-transform infrared spectroscopy (FTIR).
Results: We found that VPA induces increased levels of H3K4me2/me3 and H3K9me, which are indicative
of chromatin activation. Particularly, H3K4me2 markers appeared intensified close to the nuclear
periphery, which may suggest their implication in increased transcriptional memory. The abundance of
H3K4me2/me3 in the presence of VPA was associated with increased methyltransferase KMT2D gene
expression. VPA induced hypomethylation of H3K9me2, which is associated with gene silencing, and
concomitant with the demethylase KDM3A, it increased gene expression. Although VPA induces increased
H3K27me/me3 levels, it is suggested that the role of the methyltransferase EZH2 in this context
could be affected by interactions with this drug.
Conclusion: Histone FTIR spectra were not affected by VPA under present experimental conditions.
Whether our epigenetic results are consistent with VPA affecting the aggressive tumorous state of HeLa
cells, further investigation is required.