Enhanced potentiation of cisplatin cytotoxicity in human ovarian carcinoma cells by prolonged glutathione depletion

235

123

Summary The role of glutathione (GSH) and GSH-S-transferase (GST) activity in modulating the cytotoxicity of four platinum drugs and melphalan was evaluated in eight human ovarian carcinoma cell lines. The cell lines were established from solid and ascitic tumours from pretreated and untreated patients, and showed a wide spectrum of sensitivity to several platinum II and in the sensitive (CHI) line after GSH depletion. Moreover the dose modification factor (DMF) for the PtII agents were lower than those for PtIV agents in the three cell lines. The dose modification factor for tetraplatin after BSO treatment was similar to that observed for melphalan in all three cell lines. In the SKOV-3 cell line extending the BSO pretreatment period to 48 h from 24 h marginally reduced the cytotoxicity of cisplatin, whereas the cytotoxicity of the other three drugs remained similar to that observed after 24 h BSO pretreatment. In contrast, extending the BSO treatment to 24 h after drug exposure potentiated the cytotoxicity of cisplatin, CHIP and tetraplatin. The significance of these results in relation to the role of GSH in the mechanism of action of PtII and PtIV drugs is discussed.

Section: Discussionmentioning

confidence: 88%

mentioning

confidence: 99%

The relationships between glutathione, glutathione-S-transferase and cytotoxicity of platinum drugs and melphalan in eight human ovarian carcinoma cell lines

Mistry

Kèlland²,

Abel³

et al. 1991

235

123

“…In the present study, we performed a parallel comparison of oxaliplatin-resistant S3 cells and their parental counterparts in terms of GSH level, drug accumulation, platinum/DNA adduct formation, and DNA repair for platinum drugs. Increased intracellular GSH has been previously associated with platinum resistance in many studies (Andrews et al, 1985;el-akawi et al, 1996). In addition, GST-p is a metabolic enzyme which participates in the detoxification of platinum derivatives and is an important mediator of both intrinsic and acquired resistance to platinum (Cullen et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

Combined modalities of resistance in an oxaliplatin-resistant human gastric cancer cell line with enhanced sensitivity to 5-fluorouracil

Chen

Tsou

et al. 2007

To identify mechanisms underlying oxaliplatin resistance, a subline of the human gastric adenocarcinoma TSGH cell line, S3, was made resistant to oxaliplatin by continuous selection against increasing drug concentrations. Compared with the parental TSGH cells, the S3 subline showed 58-fold resistance to oxaliplatin; it also displayed 11-, 2-, and 4.7-fold resistance to cis-diammine-dichloroplatinum (II) (CDDP), copper sulphate, and arsenic trioxide, respectively. Interestingly, S3 cells were fourfold more susceptible to 5-fluorouracilinduced cytotoxicity due to downregulation of thymidylate synthase. Despite elevated glutathione levels in S3 cells, there was no alteration of resistant phenotype to oxaliplatin or CDDP when cells were co-treated with glutathione-depleting agent, l-buthionine-(S,R)-sulphoximine. Cellular CDDP and oxaliplatin accumulation was decreased in S3 cells. In addition, amounts of oxaliplatin-and CDDP -DNA adducts in S3 cells were about 15 and 40% of those seen with TSGH cells, respectively. Western blot analysis showed increased the expression level of copper transporter ATP7A in S3 cells compared with TSGH cells. Partial reversal of the resistance of S3 cells to oxaliplatin and CDDP was observed by treating cell with ATP7A-targeted siRNA oligonucleotides or P-type ATPaseinhibitor sodium orthovanadate. Besides, host reactivation assay revealed enhanced repair of oxaliplatin-or CDDP-damaged DNA in S3 cells compared with TSGH cells. Together, our results show that the mechanism responsible for oxaliplatin and CDDP resistance in S3 cells is the combination of increased DNA repair and overexpression of ATP7A. Downregulation of thymidylate synthase in S3 cells renders them more susceptible to 5-fluorouracil-induced cytotoxicity. These findings could pave ways for future efforts to overcome oxaliplatin resistance.

“…Figure 4 shows a representative experiment indicating that maximum staining was obtained by 50 min, and this staining time was used for all Eastman (1983Eastman ( , 1991 (Isonishi et al, 1990). This drug interaction is truly synergistic when formally examined by isobologram or median effect analysis (Berebaum, 1989;Isonishi et al, 1990 (Mann et al, 1990) and a small increase in GSH (Andrews et al, 1988) (Friedberg, 1985), including HI histone (Sahoun et al, 1983), RNA polymerase II (Chuang et al, 1987), topoisomerase (Sahyoun et al, 1986;Samuels et al, 1989), and DNA polymerase (Krauss et al, 1987). Finally, it is important to note that, in addition to PKC, n-and P-chimaerin have now been identified as targets for the binding of TPA (Ahmed et al, 1993;Leung et al, 1993), and it is possible that the effects on platinum-containing drug sensitivity are mediated by activation of signal transduction pathways other than those in which PKC is involved.…”

Section: Methodsmentioning

confidence: 99%

“…(Disaia et al, 1972). The characteristics of this line and its growth conditions have been previously described (Andrews et al, 1985). Sensitivity to the cytotoxic effect of the platinum compounds was determined by clonogenic assay as previously described (Isonishi et al, 1990).…”

mentioning

confidence: 99%

Enhancement of sensitivity to platinum(II)-containing drugs by 12-O-tetradecanoyl-phorbol-13-acetate in a human ovarian carcinoma cell line

Isonishi¹,

Hom²,

Eastman³

et al. 1994

SummarySensitivity to platinum-containing drugs is believed to be a function of how much drug enters the cell, the extent of DNA adduct formation and the rate at which DNA is repaired. Activation of protein kinase C by 12-0-tetradecanoyl-phorbol-13-acetate (TPA) DDP has activity against a relatively broad range of tumours (Loehrer & Einhorn, 1984), and the antineoplastic activity of this drug is generally considered to result from its reaction with DNA. The majority of the adducts formed in DNA are guanine-guanine intrastrand cross-links; less than 1% of the adducts are interstrand cross-links, and a small fraction are DNA-protein cross-links (Masuda et al., 1990).We have previously reported that activation of protein kinase C (PKC) by TPA enhances the DPP sensitivity of the human ovarian carcinoma cell line 2008 (Ishonishi et al., 1990, indicating that the PKC signal transduction pathway can regulate one or more of the biochemical events that determine the ability of DDP to cause cell death. This observation has been confirmed in another laboratory (Basu et al., 1990). In this paper we report that activation of PKC can also sensitise cells to CBDCA and 254-S, two analogues whose biochemical pharmacology differs from that of DDP. We also report that the sensitising effect of TPA cannot be accounted for by effects on any of the four major parameters currently thought to regulate DDP sensitivity. (Disaia et al., 1972). The characteristics of this line and its growth conditions have been previously described (Andrews et al., 1985). Sensitivity to the cytotoxic effect of the platinum compounds was determined by clonogenic assay as previously described (Isonishi et al., 1990). All experiments were done using triplicate cultures of cells in logarithmic growth, and each experiment was repeated a minimum of three times. Materials and methods Materials[3H]DEP and CBDCA uptake Subconfluent monolayers of 2008 cells were treated with 37°C RPMI-1640 medium containing 5 tLM [3H]DEP (10 yCi ml-') for 1 h. The medium was then aspirated, and the cells were washed rapidly four times with 4°C phosphate-buffered saline (PBS). (1976).Glutathione content and glutathione-S-transferase activity GSH content was measured by adjusting cells to 106ml-' and staining them with 25 tM MCB in complete medium at