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Noor-Ul-Ain Shekoh, Mohamed Mohamed, Sonali Nashine, Baruch D Kuppermann, Cristina M Kenney; Bevacizumab can inhibit histone deacetylase (HDAC) activity in ARPE-19 cells. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3986.
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© ARVO (1962-2015); The Authors (2016-present)
Vascular endothelial growth factor (VEGF) plays a key role in the pathogenesis of choroidal neovascularization and has been the main target for wet AMD therapy. The variability in patients’ response to anti-VEGF therapy has been a major focus of interest. Several clinical, behavioural and genetic factors have been proposed to influence the outcome of anti-VEGF therapy.Epigenetics is the study of covalent modifications of the genome that alter gene structure and function without changing its sequence. Examples include DNA methylation, along with histone acetylation and deacetylation. Epigenetic mechanisms can explain the impact of gene-environment interactions on different disease phenotypes.The purpose of this study is to investigate the possible effects of an anti-VEGF drug, bevacizumab, on histone deacetylase (HDAC) activity in ARPE-19 cells.
ARPE-19 cells were plated for 24 hours, then treated with either bevacizumab at 1X concentration of the clinical intravitreal dose (12.5 μL/mL), or 0.3 μM trichostatin A (an HDAC inhibitor), or a combination of both drugs. Untreated cells were used as controls.Proteins were extracted using RIPA cell lysis buffer containing a protease inhibitor cocktail. Cell lysates were centrifuged and stored at -80 C until further use.HDAC activities were measured with a fluorometric HDAC assay kit and a fluorimeter plate reader using the 350 nm excitation and 440 nm emission wavelengths. Fluorescence was quantified in Relative Fluorescence Units (RFU). Unpaired t-test was used for statistical analysis and P value <0.05 was considered significant.
Both bevacizumab (B) and trichostatin A (T) significantly decreased HDAC activities compared to untreated (UNT) cells (P= 0.03 and 0.01, respectively). A combination of both drugs (B+T) significantly inhibited HDAC activity as well (P= 0.02) compared to untreated cultures, but a synergistic effect could not be demonstrated (Figure 1).
Our results show that bevacizumab can inhibit HDAC activity in ARPE-19 cells. This, in turn, indicates that anti-VEGF drugs may alter the acetylation status in the retina. This is important because it suggests that the so called drug “resistance” may be in part due to the treatment interaction with different “epigenome” profiles that occur in different patients.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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