A newly synthesized bifunctional inhibitor, W-77, enhances adriamycin activity against human ovarian carcinoma cells.
A newly synthesized calmodulin antagonist, (S)-P-(2-aminoethyloxy)-N-[2-(4-benzyloxy-carbonylpiperazinyl++ +)-1-(P-methoxybenzyl)ethyl]-N-methylbenzenesulfonamide dihydrochloride (W-77), acts as a calcium-independent uncompetitive antagonist which binds to glutathione-S-transferase (GST). We purified GST from human placenta using drug affinity chromatography on a column of W-77 coupled with Sepharose 6B and demonstrated that W-77 bound to GST. A spectrophotometric assay also showed that W-77 inhibited GST activity. We prepared Adriamycin-resistant and -sensitive cells from human ovarian serous cystadenocarcinomas. Immunoblot analysis revealed that GST expression was increased in the Adriamycin-resistant cells. We also purified GST from Adriamycin-resistant cells and found that W-77 bound to the GST obtained from these ovarian carcinoma cells. Adriamycin resistance was partially overcome by the addition of W-77 (10 microM) to the cultured cells. In addition, we investigated the effect of W-77 on P-glycoprotein. Northern blot analysis revealed MDR1 gene expression in Adriamycin-resistant cells. Although W-77 was less potent in increasing the intracellular Adriamycin content than verapamil, it was more effective in overcoming Adriamycin resistance. These results suggest that W-77 enhances the antitumor activity of Adriamycin by inhibiting both GST and P-glycoprotein.
Maeda
O
O
Department of Obstetrics and Gynecology, Nagoya University School of Medicine, Japan.
Terasawa
M
M
Ishikawa
T
T
Oguchi
H
H
Mizuno
K
K
Kawai
M
M
Kikkawa
F
F
Tumoda
Y
Y
Hidaka
H
H
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002470:Cell Survival / Q000187:drug effects; D003536:Cystadenocarcinoma / Q000188:drug therapy; D004273:DNA, Neoplasm / Q000235:genetics; D004317:Doxorubicin / Q000008:administration & dosage*; D004351:Drug Resistance; D004357:Drug Synergism; D004976:Ethacrynic Acid / Q000494:pharmacology; D005260:Female; D015870:Gene Expression; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D066298:In Vitro Techniques; D008562:Membrane Glycoproteins / Q000235:genetics; D010051:Ovarian Neoplasms / Q000188:drug therapy; D010879:Piperazines / Q000494:pharmacology* / Q000633:toxicity; D012333:RNA, Messenger / Q000235:genetics; D013449:Sulfonamides / Q000494:pharmacology* / Q000633:toxicity; D014407:Tumor Cells, Cultured / Q000187:drug effects; D000096926:Benzenesulfonamides
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002147:Calmodulin; D004273:DNA, Neoplasm; D004317:Doxorubicin; D004976:Ethacrynic Acid; D005982:Glutathione Transferase; D008562:Membrane Glycoproteins; D010879:Piperazines; D012333:RNA, Messenger; D013449:Sulfonamides; C080983:W 77; D000096926:Benzenesulfonamides