15-Deoxy-Δ12,14-prostaglandin J2 stabilizes, but functionally inactivates p53 by binding to the cysteine 277 residue

Abstract

15-Deoxy-D 12,14 -prostaglandin J 2 (15d-PGJ 2 ), a representative cyclopentenone prostaglandin, has many interesting biological effects. In this study, treatment of human breast cancer cells (MCF-7) with 15d-PGJ 2 led to accumulation of p53 protein. However, the p53 DNA binding and its transcriptional activity were significantly reduced. 15d-PGJ 2 directly modified p53 as verified by reacting recombinant p53 with biotinylated 15d-PGJ 2 . 9,10-Dihydro-15-deoxy-D 12,14 -prostaglandin J 2 lacking the electrophilic a,b-unsaturated functionality failed to inhibit p53 DNA binding as well as to modify p53. Moreover, by conducting an in vitro [ 35 S]-labeled p53 translation assay, we identified cysteine 277 as a putative site of p53 modification by 15d-PGJ 2 . The DNA-binding ability of a mutant p53 in which cysteine 277 was substituted by alanine was virtually unaffected by 15d-PGJ 2 . Likewise, p53 binding activity of biotinylated 15d-PGJ 2 was abolished in mutant cells. In addition, cells expressing wild-type p53 exhibited p53 protein stability to a greater extent than mutant C277A cells. In conclusion, 15d-PGJ 2 can undergo nucleophilic addition to p53, presumably at the cysteine 277 residue, rendering this tumor suppressor less susceptible to proteasomal degradation.

PPAR-γ Ligands Repress TGFβ-Induced Myofibroblast Differentiation by Targeting the PI3K/Akt Pathway: Implications for Therapy of Fibrosis

“…These observations offer an additional possibility that CDDO and 15d-PGJ 2 could directly bind to the active site of a signaling molecule involved in the Akt pathway. One study has shown that biotinylated CDDO is capable of binding and thus inactivating the active site of PTEN [37], and 15d-PGJ 2 is capable of inhibiting the activities of proteins through direct covalent modification [51], [52]. Further studies involving biochemical approaches should help us understand the exact nature of action of compounds involving electrophilic carbon.…”

Electrophilic Lipid Mediator 15-Deoxy-Δ12,14-Prostaglandin J2 Modifies Glucocorticoid Signaling via Receptor SUMOylation

“…In this study, we examined the effect of 15d-PGJ 2 on GR SUMOylation and glucocorticoid-regulated gene programs. 15d-PGJ 2 has been shown to trigger cell signaling cascades via directly interacting with proteins containing reactive cysteine residues (29,30,36). 15d-PGJ 2 principally activates the NRF2 pathway by modifying KEAP1, the inhibitory partner of NRF2, which results in stabilization and increased chromatin binding of the NRF2 and activation of genes such as HMOX1 that are involved in the cytoprotection against oxidative stress (25,26,28).…”

Identification of Two Reactive Cysteine Residues in the Tumor Suppressor Protein p53 Using Top-Down FTICR Mass Spectrometry

“…Cys277 has also been identified as a possible substrate for selenomethionine (SeMet)-dependent redox-regulation of p53 [15], and it has been postulated that the redox-state of Cys277 serves as a switch to activate DNA repair machinery [47]. Furthermore, an electrophilic cyclopentenone prostaglandin, 15-deoxy-Δ 12,14 -prostaglandin J 2 (15d-PGJ 2 ), has been shown to bind to Cys277 in vivo, leading to an increase in p53 stability and reduction of its transcriptional activity [48]. Cys277 is located in the conserved p53 motif BOX-V (amino acid residues 272-288).…”