Cyclopentenone Prostaglandins with Dienone Structure Promote Cross-Linking of the Chemoresistance-Inducing Enzyme Glutathione Transferase P1-1

Abstract

Glutathione transferase P1-1 (GSTP1-1) plays crucial roles in cancer chemoprevention and chemoresistance and is a key target for anticancer drug development. Oxidative stress or inhibitor-induced GSTP1-1 oligomerization leads to the activation of stress cascades and apoptosis in various tumor cells. Therefore, bivalent glutathione transferase (GST) inhibitors with the potential to interact with GST dimers are been sought as pharmacological and/or therapeutic agents. Here we have characterized GSTP1-1 oligomerization in response to various endogenous and exogenous agents. Ethacrynic acid, a classic GSTP1-1 inhibitor, 4-hydroxy-nonenal, hydrogen peroxide, and diamide all induced reversible GSTP1-1 oligomerization in Jurkat leukemia cells through the formation of disulphide bonds involving Cys47 and/or Cys101, as suggested by reducing and nonreducing SDS-polyacrylamide gel electrophoresis analysis of cysteine to serine mutants. Remarkably, the electrophilic prostanoid 15-deoxy-⌬ 12,14 -prostaglandin J 2 (15d-PGJ 2 ) induced irreversible GSTP1-1 oligomerization, specifically involving Cys101, a residue present in the human but not in the murine enzyme. 15d-PGJ 2 -induced GSTP1-1 cross-linking required the prostaglandin (PG) dienone structure and was associated with sustained c-Jun NH 2 -terminal kinase activation and induction of apoptosis. It is noteworthy that 15d-PGJ 2 elicited GSTP1-1 cross-linking in vitro, a process that could be mimicked by other dienone cyclopentenone PG, such as ⌬ 12 -PGJ 2 , and by the bifunctional thiol reagent dibromobimane, suggesting that cyclopentenone PG may be directly involved in oligomer formation. Remarkably, ⌬ 12 -PGJ 2 -induced oligomeric species were clearly observed by electron microscopy showing dimensions compatible with GSTP1-1 tetramers. These results provide the first direct visualization of GSTP1-1 oligomeric species. Moreover, they offer novel strategies for the modulation of GSTP1-1 cellular functions, which could be exploited to overcome its role in cancer chemoresistance.

Identification of Aldo-Keto Reductase AKR1B10 as a Selective Target for Modification and Inhibition by Prostaglandin A1: Implications for Antitumoral Activity

“…Immediately before flow cytometry analysis, cells were centrifuged and resuspended in 0.5% NP-40, 25 mg/mL propidium iodide and 25 mg/mL RNase A, and incubated in this solution for 15 minutes at room temperature. Apoptosis was detected by binding of Annexin V and propidium iodide staining, as described (31).…”

Molecular Interactions and Implications of Aldose Reductase Inhibition by PGA1 and Clinically Used Prostaglandins

“…cyPGs bind to and modulate transcription factors (Cernuda-Morollón et al, 2001;Kim and Surh, 2006;Pérez-Sala, 2011), activate the antioxidant response (Levonen et al, 2004;Martínez et al, 2012), inactivate detoxifying enzymes like glutathione transferases (Sánchez-Gómez et al, 2010), and induce antiinflammatory and antiproliferative effects , for which they have been proposed as therapeutic tools (Fukushima et al, 2001;Homem de Bittencourt et al, 2007).…”

Inhibition of Anthracycline Alcohol Metabolite Formation in Human Heart Cytosol: A Potential Role for Several Promising Drugs

“…PGs are a family of biologically active eicosanoids that are involved in the regulation of numerous physiopathological processes, including inflammation, cellular growth, and differentiation (Sánchez-Gómez et al, 2010;Garzón et al, 2011;Díez-Dacal and Pérez-Sala, 2012). Within the PG family, the A and J series, known as cyPGs, possess an a,b-unsaturated carbonyl group in the cyclopentene ring, which confers high reactivity toward nucleophiles, such as thiol groups, and can lead to the formation of covalent adducts by Michael addition reactions (Sánchez-Gómez et al, 2010;Garzón et al, 2011; Díez-Dacal and Pérez-Sala, 2012).…”

“…PGs are a family of biologically active eicosanoids that are involved in the regulation of numerous physiopathological processes, including inflammation, cellular growth, and differentiation (Sánchez-Gómez et al, 2010;Garzón et al, 2011;Díez-Dacal and Pérez-Sala, 2012). Within the PG family, the A and J series, known as cyPGs, possess an a,b-unsaturated carbonyl group in the cyclopentene ring, which confers high reactivity toward nucleophiles, such as thiol groups, and can lead to the formation of covalent adducts by Michael addition reactions (Sánchez-Gómez et al, 2010;Garzón et al, 2011; Díez-Dacal and Pérez-Sala, 2012). Post-translational modification of proteins by cyPGs (referred to as prostanylation or eicosanylation) affects the function of specific transcription factors, tumor suppressors, and antioxidant enzymes, and therefore seems to be responsible for several of the biologic effects of cyPGs (Garzón et al, 2011;Díez-Dacal and Pérez-Sala, 2012).…”