N-(2′-Hydroxyphenyl)-2-propylpentanamide (OH-VPA), a histone deacetylase inhibitor, induces the release of nuclear HMGB1 and modifies ROS levels in HeLa cells

Abstract

N-(2′-Hydroxyphenyl)-2-propylpentanamide (OH-VPA) is a valproic acid (VPA) derivative with improved antiproliferative activity toward breast cancer (MCF-7, MDA-MB-231, and SKBr3) and human cervical cancer cell lines (HeLa) compared to that of VPA. However, the pharmacological mechanism of OH-VPA activity remains unknown. High-mobility group box 1 (HMGB1) is an important enzyme that is highly expressed in tumor cells and has a subcellular localization that is dependent on its acetylation or oxidative state. Therefore, in this study, we analyzed changes in HMGB1 sub-cellular localization and reactive oxygen species (ROS) as well as changes in HeLa cell viability in response to treatment with various concentrations of OH-VPA. This compound is formed by the covalent bond coupling VPA to a phenol group, which is capable of acting as a free radical scavenger due to its chemical similarities to quercetin. Our results show that OH-VPA induces nuclear to cytoplasmic translocation of HMGB1, as demonstrated by confocal microscopy observations and infrared spectra that revealed high quantities of acetylated HMGB1 in HeLa cells. Cells treated with 0.8 mM OH-VA exhibited decreased viability and increased ROS levels compared with the lower OH-VPA concentrations tested. Therefore, the antiproliferative mechanism of OH-VPA may be related to histone deacetylase (HDAC) inhibition, as is the case for VPA, which promotes high HMBG1 acetylation, which alters its subcellular localization. In addition, OH-VPA generates an imbalance in cellular ROS levels due to its biochemical activity.

N-(2′-Hydroxyphenyl)-2-Propylpentanamide (HO-AAVPA) Inhibits HDAC1 and Increases the Translocation of HMGB1 Levels in Human Cervical Cancer Cells

“…In addition, HMGB1 was translocated from the nucleus to the cytoplasm in the cells treated with HO-AAVPA, suggesting that HMGB1 is acetylated and it cannot back to the nucleus, therefore, acetylated HMGB1 could exit from the cell and participate in cell death [ 13 , 15 ]. In addition, an increase of HMGB1 in the cytoplasm is in agreement with the amount of O 2 −· produced at each concentration, as was demonstrated in HeLa cells in which after HO-AAVPA treatment induced oxidative stress and also the levels of acetylated HMGB1 were increased, and these results were also linked with the possible HDAC1 inhibition [ 26 , 31 ].…”

“…Therefore, these results correlated with docking results showing that HO-AAVPA is capable to be accommodate at catalytic site of HDAC1 enzyme, suggesting that it affects the deacetylation activity. Thus, it explains the increase acetylation of HMGB1 due to HDAC1 inhibition, then, the HO-AAVPA favored the acetylate HMGB1 [26,[31][32][33][34]. All these processes, such as HDAC1 inhibition as well HMGB1 acetylation, could be related with the cytotoxic effect observed for HO-AAVPA (IC50 = 1.6 mM at 48 h).…”

“…The action mechanism of HO-AAVPA in promoting cell death had not been elucidated. There is an initial attempt in which HO-AAVPA was found to increase the levels of acetylated HMGB1 in HeLa cells, a finding that may have been the result of HDAC inhibitory effects [26].…”

Untargeted LC-MS/MS Metabolomics Study on the MCF-7 Cell Line in the Presence of Valproic Acid

“…Analysis of cysteine through the predictive metabolic results allows us to reinforce the importance of this amino acid in the effect of VPA due to its participation in several metabolic pathways such as coenzyme biosynthesis, cysteine biosynthesis and degradation, hydrogen sulfide biosynthesis and homocysteine degradation, serotonin, and taurine biosynthesis, and others. Cell redox capacity is another worth mentioning subject, Contis-Montes de Oca et al (2018) found that HO-VPA, a novel compound partly based on VPA which shares many of its effects, increased ROS levels (through HMB1 acetylation) and decreased cell viability in HeLa cells [ 32 , 33 ]. Reduction in cysteine availability, a known limiting factor in GSH synthesis, may play a key role in cell death through glutathione shortage [ 30 ].…”

Histone Deacetylase Inhibitors as Therapeutic Interventions on Cervical Cancer Induced by Human Papillomavirus

“…(Saito et al, 1999;Lauffer et al, 2013;Gorshkov et al, 2019) HDAC1 19) presented an activity against HeLa cells and IC 50 value of 0.92 mM and increased intracellular levels of ROS after treatment with a concentration of 0.8 mM. (Oca et al, 2018;Sixto-López et al, 2020) HDAC1:153.78 µM HDAC6:>1000 µM HDAC8:>1000 µM Luotonin A derivative (20) Inhibition of HDAC 1 and 2 Compound (20) presented an antiproliferative activity against HeLa cells identical to Luotonin A, its precursor; however, the selective index was 4.4 times superior for the synthesized compound compared to Luotonin A. Compound (20) treatment also resulted in induction of p53 protein and G1 arresting cell cycle.…”