Reversal of multidrug resistance by small interfering double-stranded RNAs in ovarian cancer cells.
OBJECTIVE
Cisplatin (DDP) resistance is a major barrier to overcome before chemotherapy can become curative for most patients presenting with ovarian cancer. In this study, we investigated the effect of siRNAs on expression of p-gp, GST-pi mRNA and protein in cisplatin-resistant human ovarian cancer cells in order to restore sensitivity to DDP.


METHODS
Small interfering double-stranded RNAs (siRNA) were designed to target p-glycoprotein (p-gp) and glutathione S-transferases (GST) mRNA as a strategy to inhibit both resistant gene expression at the mRNA level. Using Real-Time PCR and western blotting assay the changes of the RNA and protein levels of both drug resistant genes were studied.


RESULTS
Transfection of MDR-1 and GST siRNAs into human multi-drug resistance (MDR) ovarian cancer cell lines, COC1/DDP and SKOV3/DDP, resulted in a time-dependent inhibition of both gene expressions with the decline of the IC(50) values but had no effect on the expression of a-Tubulin. Inhibition of P-gp and GST expression by siRNA enhanced the intracellular accumulation of and restored sensitivity to DDP.


CONCLUSIONS
These studies suggest that p-gp and GST siRNAs are effective inhibitors of MDR gene expression and reverse the resistance of ovarian carcinomas. Our studies may provide a new insight to develop siRNAs as a novel therapeutic tool for the treatment of ovarian carcinomas.
Zhang
Tao
T
Center of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200040, China.
Guan
Ming
M
Jin
Hong Yan
HY
Lu
Yuan
Y
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D000970:Antineoplastic Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000235:genetics*; D019008:Drug Resistance, Neoplasm; D005260:Female; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D014162:Transfection
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D007527:Isoenzymes; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; D002945:Cisplatin