Direct Binding of Cisplatin to p22phox, an Endoplasmic Reticulum (ER) Membrane Protein, Contributes to Cisplatin Resistance in Oral Squamous Cell Carcinoma (OSCC) Cells

Abstract

Prolonged treatment with cisplatin (CDDP) frequently develops chemoresistance. We have previously shown that p22phox, an endoplasmic reticulum (ER) membrane protein, confers CDDP resistance by blocking CDDP nuclear entry in oral squamous cell carcinoma (OSCC) cells; however, the underlying mechanism remains unresolved. Using a fluorescent dye-labeled CDDP, here we show that CDDP can bind to p22phox in both cell-based and cell-free contexts. Subsequent detection of CDDP-peptide interaction by the Tris-Tricine-based electrophoresis revealed that GA-30, a synthetic peptide matching a region of the cytosolic domain of p22phox, could interact with CDDP. These results were further confirmed by liquid chromatography–mass spectrometry (LC–MS) analysis, from which MA-11, an 11-amino acid subdomain of the GA-30 domain, could largely account for the interaction. Amino acid substitutions at Cys50, Met65 and Met73, but not His72, significantly impaired the binding between CDDP and the GA-30 domain, thereby suggesting the potential CDDP-binding residues in p22phox protein. Consistently, the p22phox point mutations at Cys50, Met65 and Met73, but not His72, resensitized OSCC cells to CDDP-induced cytotoxicity and apoptosis. Finally, p22phox might have binding specificity for the platinum drugs, including CDDP, carboplatin and oxaliplatin. Together, we have not only identified p22phox as a novel CDDP-binding protein, but further highlighted the importance of such a drug-protein interaction in drug resistance.

HOXA1 silencing inhibits cisplatin resistance of oral squamous cell carcinoma cells via IκB/NF-κB signaling pathway

“…The mechanism of cisplatin resistance has been widely discussed and unveiled, such as DNA repair proteins and stress proteins [11]. Many drug targets were reported to mediate resistance of OSCC cells to cisplatin, including excision repair cross-complementation group 1 protein [22], endoplasmic reticulum membrane protein p22phox [23], NF-κB [24], tongue cancer resistance-associated protein 1 (TCRP1) [25], and miR-21 [26]. The p22phox may directly bind to small molecule anticancer drugs like platinum, and increase resistance of cancer cells to platinum drugs [27].…”

Urinary Sediment mRNA Level of CREBBP and CYBA in Children With Steroid-Resistant Nephrotic Syndrome

“…It can induce oxidative stress damage (40). Hung et al reported that the overexpression of p22phox sequestered cisplatin and caused defective cisplatin entry into the nucleus in oral squamous cell carcinoma (41). CYBA mutation or p22phox expression was closely related to insulin resistance in metabolic syndrome by affecting oxidative stress (42,43).…”

Inhibition of p22phox Suppresses Epithelial Ovarian Cancer Cell Proliferation and Tumorigenesis

“…To date, cisplatin-or paclitaxel-based chemotherapy, combined with other chemotherapeutic agents, remains the first-line treatment for ovarian cancers [28]. Recent reports have shown that p22 phox is a cisplatin-resistant gene that suppresses DNA adduct-induced apoptosis by blocking cisplatin uptake into the nucleus and activating the PI3K/Akt pathway [13]. Our study found that interfering with p22 phox function could enhance the drug sensitivity of ovarian cancer cells to cisplatin or paclitaxel and thus provides a new concept for the treatment of ovarian cancer.…”

“…In addition, downregulation of p22 phox inhibited Akt-dependent phosphorylation of tuberin and stabilized tuberin protein levels in VHL-deficient renal carcinoma cells [11]. Furthermore, p22 phox has been reported to function as a cisplatin-resistant factor that suppresses DNA adduct-induced apoptosis by blocking cisplatin uptake into the nucleus and activating the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in oral squamous cell carcinoma [12,13]. However, whether the expression of p22 phox occurs in the different epithelial ovarian cancer types and the role of p22 phox in epithelial ovarian cancer progression has not been established.…”