Targeting GSTP1-1 induces JNK activation and leads to apoptosis in cisplatin-sensitive and -resistant human osteosarcoma cell lines

Abstract

The effect of the glutathione transferase P1-1 (GSTP1-1) targeting has been investigated in both sensitive (U-2OS) and cisplatin-resistant (U-2OS/CDDP4 mg) human osteosarcoma cell lines. Despite the different enzyme's content, inhibition of GSTP1-1 by 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX) causes the activation of c-Jun N-terminal kinase (JNK) and apoptosis in both cell lines. However, different time courses of JNK activation and cell responses are observed. Whereas in the U-2OS/CDDP4 mg cell line drug treatment results in an early increase of caspase activity and secondary necrosis, in the U-2OS cells it mainly causes an early cell cycle arrest followed by apoptosis. In order to elucidate the action mechanism of NBDHEX we performed a proteomic investigation by label-free nLC-MS E . The high-throughput analysis associated with a bioinformatic tool suggested the involvement of the TNF receptor associated factor (TRAF) family in the cellular response to the drug treatment. We report experimental evidence of the interaction between GSTP1-1 and TRAF2 and we demonstrate that NBDHEX is able to dissociate the GSTP1-1 : TRAF2 complex. This restores the TRAF2 : ASK1 signaling, thereby leading to the simultaneous and prolonged activation of JNK and p38. These mitogenactivated protein kinases (MAPKs) mediate different effects: JNK is crucial for apoptosis, whereas p38 causes an increase in the p21 level and a concomitant cell cycle arrest. Our study shows that GSTP1-1 plays an important regulatory role in TRAF signaling of osteosarcoma and discloses new features of the action mechanism of NBDHEX that suggest potentially practical consequences of these findings.

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

“…We have previously demonstrated that NBDHEX activates the MAPK signaling pathway in several tumor cell lines. (30)(31)(32)(33)36,38) In accordance with previous studies, we observed a rapid and sustained increase in the phospho-active form of JNK and p38 in all mesothelioma cell lines treated with NBDHEX (Fig. 5a).…”

“…(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. (31)(32)(33) Given the promising results already observed in several different tumors, (31)(32)(33)(34)(35)(36)(37)(38) in the present study we evaluate the effect of NBDHEX in four human malignant mesothelioma cell lines, MSTO-211H, MPP89, MM-B1 and Mero 48a, featuring the two most common phenotypes, epithelioid and biphasic. The mechanism of cell death triggered by NBDHEX and the in vitro efficacy of NBDHEX in combination with CDDP are investigated.…”

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

“…We have previously demonstrated that GSTP1-1 contributes to osteosarcoma chemoresistance, and that targeting GSTP1-1 with 1 may represent a new therapeutic strategy for the treatment of this poorly responding tumor [18,25,26]. Thus, we evaluated the cytotoxic effect of the new NBD compounds 2e40 on the human osteosarcoma U-2OS cell line (Table 1).…”

JNK1/2 expression and modulation of STAT3 signaling in oral cancer

“…Activation of the JNK signaling pathway in response to several extracellular stimuli has been viewed as a critical event that leads to apoptotic or non-apoptotic cell death in several cells, including bronchial epithelial, human hepatoma, hepatocellular carcinoma and osteosarcoma cells (36)(37)(38)(39). By contrast, JNK has also been reported to promote cell transformation and proliferation in cancer stem cells (40).…”