New Insights into the Mechanism of JNK1 Inhibition by Glutathione Transferase P1-1

Abstract

The role played by glutathione transferase P1-1 (GSTP1-1) in modulating the c-Jun N-terminal kinase (JNK) pathway has been extensively investigated using JNK isoforms known to exert opposite effects in the cells. We have expressed isoform JNK1α2, which has been reported to transmit a pro-apoptotic signal, and we have analyzed both the phosphorylation level and the activity of this kinase in the presence of GSTP1-1. Contrary to what previous studies suggest, we found that GSTP1-1 is able to form a complex with the unphosphorylated and inactive JNK1α2 isoform, even in the absence of the substrate. We also analyzed the consequences of this interaction on the activity of both enzymes. The complex strongly reduced the extent of activation of JNK1α2 and preserved GSTP1-1 from inactivation. Unexpectedly , glutathione (GSH) exerted a negative effect on the affinity of GSTP1-1 for JNK1α2, suggesting that the intracellular levels of this thiol may allow a fine-tuning of the MAPK signaling pathway. Moreover, we found that the adduct formed by GSH and the strong GSTP1-1 inhibitor NBDHEX abolishes the interaction between GSTP1-1 and JNK1α2. These data confirm and extend at the molecular level previous evidence obtained in tumor cell lines.

Synthesis and structure–activity relationship of new cytotoxic agents targeting human glutathione-S-transferases

“…At the cellular level, 1 causes the rapid disruption of the JNK1-GSTP1-1 and TRAF2-GSTP1-1 complexes, resulting in prolonged cell cycle arrest and apoptosis [6,7]. This pro-apoptotic mechanism has been described in vitro in a variety of tumor cell lines (leukemia, osteosarcoma, melanoma and mesothelioma) [13,17e19].…”

Glutathione S‐transferase P1‐1 as a target for mesothelioma treatment

“…Indeed, several published investigations report that the GST isoenzyme GSTP1-1 binds directly to the MAPK JNK, inhibiting its activation. (25)(26)(27) Recent studies have shown that the GSTP1-1 and GSTM1-1 isoenzymes are able to inhibit the activity of the apoptosis signal-regulating kinase (ASK1), which, in turn, is responsible for the activation of JNK and p38 kinases.(28) We have designed and synthesized a class of nitro-benzoxadiazole derivatives, which act as efficient and specific inhibitors of the GST catalytic and anti-apoptotic activity.(29) The most promising derivative is 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX), a non-glutathione peptidomimetic molecule that is known to induce the dissociation of the GSTP1-JNK complex, leading to the activation of JNK and to the programmed cell death thereafter. (29,30) An important property of this compound is that it is not recognized as a substrate by the ABC transporters P-glycoprotein and MRP1 and is highly cytotoxic against tumor cells that overexpress these transporters.…”

“…Indeed, several published investigations report that the GST isoenzyme GSTP1-1 binds directly to the MAPK JNK, inhibiting its activation. (25)(26)(27) Recent studies have shown that the GSTP1-1 and GSTM1-1 isoenzymes are able to inhibit the activity of the apoptosis signal-regulating kinase (ASK1), which, in turn, is responsible for the activation of JNK and p38 kinases. (28) We have designed and synthesized a class of nitro-benzoxadiazole derivatives, which act as efficient and specific inhibitors of the GST catalytic and anti-apoptotic activity.…”

Research Article Synergic effect of oral contraceptives, GSTP1 polymorphisms, and high-risk HPV infection in development of cervical lesions.

“…The GSTP1 gene, a member of the GST Pi class, has approximately 3.2 kb and is found on chromosome 11q13 (Rodríguez et al, 2014). GSTP1 is involved in cell protection through the apoptotic process, and its polymorphic forms do not synthesize essential proteins that bind to enzymes present in the JNK pathway (De Luca et al, 2012). GSTP1 comprises nine exons; the most common polymorphisms are the A/G transition at nucleotide 313 (isoleucine/valine substitutioncodon 105 in exon 5) (rs1695) (Elhoseiny et al, 2014).…”