Quercetin enhancement of arsenic‐induced apoptosis via stimulating ROS‐dependent p53 protein ubiquitination in human HaCaT keratinocytes

Abstract

In this study, QUE, but not the structurally related chemical, rutin, enhanced the cytotoxicity of arsenic trioxide (As(+3)) against the viability of normal human HaCaT keratinocytes via induction of apoptosis. QUE enhancement of As(+3)-mediated apoptosis was accompanied by increased intracellular peroxide production according to a DCFH-DA analysis, and DNA ladders induced by QUE/As(+3) were inhibited by adding the antioxidative compound, N-acetyl cysteine (NAC). A loss of the mitochondrial membrane potential by QUE/As(+3) was observed according to DiOC(6) staining in concert with increased Bax protein and cytosolic cytochrome (Cyt) c protein expression in HaCaT cells, which was prevented by the addition of NAC. A decrease in the p53 protein with increased protein ubiquitination was detected in QUE/As(+3)-treated HaCaT cells, and this was prevented by the addition of NAC. The decrease in the p53 protein by QUE/As(+3) was reversed by adding the proteasome inhibitor, MG132. L-Buthionine sulphoximine (BSO) enhanced the cytotoxicity of As(+3) against the viability of HaCaT cells with reduced p53 protein through inducing protein ubiquitination and reactive oxygen species (ROS) production, and disrupting the mitochondrial membrane potential in HaCaT cells. Additionally, QUE and BSO enhanced the cytotoxic effects of monomethylarsonous acid (MMA(+3)) but not other arsenic compounds in accordance with increased p53 protein ubiquitination in HaCaT cells. QUE plus As(+3) stimulation of apoptosis in human HaCaT keratinocytes via activating ROS-dependent p53 protein ubiquitination may offer a rationale for the use of QUE to improve the clinical efficacy of arsenics in treating psoriasis.

Arsenic Trioxide Reactivates Proteasome-Dependent Degradation of Mutant p53 Protein in Cancer Cells in Part via Enhanced Expression of Pirh2 E3 Ligase

“…Previously, we found that ATO, a drug clinically preferred for acute promyelocytic leukemia, decreases the stability of mutant p53 protein through a proteasome pathway, and blockage of proteasome pathway can alleviate the arsenic-induced mutant p53 degradation [32], [49]. In this study, we found that ATO induces expression of Pirh2 E3 ligase.…”

Reversibility of changes in brain cholinergic receptors and acetylcholinesterase activity in rats following early life arsenic exposure

“…Increased formation of malonaldehyde and protein carbonyls in frontal cortex and hippocampus of arsenic exposed rats indicate enhanced oxidative damage due to increased generation of reactive species and the finding is consistent with earlier reports (Bhadauria and Flora, 2007; Flora et al, 2009; Wang et al, 2012). As arsenic has a high affinity with thiols, it may affect free thiols and catalytic activity of proteins and enzymes containing thiols (Shen et al, 2012).…”

Skin delivery of epigallocatechin-3-gallate (EGCG) and hyaluronic acid loaded nano-transfersomes for antioxidant and anti-aging effects in UV radiation induced skin damage

“…Intracellular ROS levels in HaCaT cells were determined by measuring the oxidative conversion of cell permeable 2 0 ,7 0 -dichlorofluorescein diacetate (H 2 DCFDA) to fluorescent dichlorofluorescein (DCF) (Shen et al, 2012). The fluorescence intensity of DCF in HaCaT cells is significantly increased with UVB irradiation, while the background ROS levels in HaCaT cells are low without irradiation.…”