[Comparison of stepwise and pulse induced cisplatin-resistant ovarian cancer cell sublines].
OBJECTIVE
To investigate the mechanism responsible for acquired cisplatin resistance induced in human ovarian cancer cell lines by different methods.


METHODS
Two resistant cell lines, Skov3/CDDP-P and Skov3/CDDP-50, were established by pulse or stepwise exposures of ovarian cancer cell line Skov3 to cisplatin (CDDP) for 10-12 months with the drug sensitivity monitored by MTT test. The growth rate and cell cycle were compared. The intracellular drug concentration was measured by FACS after 1 hour incubation in 20 mumol/L ADM. The drug-resistance-associated genes: MDR1, MRP, LRP and GST-pi were monitored by RT-PCR and western blotting.


RESULTS
The resistance indexes (RI) of Skov3/CDDP-P and Skov3/CDDP-50 were 3.7 and 48.6 to cisplatin, 4.0 and 33.0 to Taxol, 2.2 and 7.3 to adriamycin, 1.5 and 3.4 to VP16, and the intracellular ADM concentration was lowered by 34.6% and 47.2% respectively. Both resistant cell lines grew slowly and exhibited changes in morphology and cell cycle. The expression of the resistance-associated genes MDR1, MRP and LRP was enhanced in both resistant cell lines. However, Skov3/CDDP-50 showed greater increase in MDR1 but Skov3/CDDP-P showed more in MRP. There were no significant changes in GST-pi expression either at mRNA or protein level. The TOPO II activity decreased slightly in both resistant cell lines.


CONCLUSIONS
Stepwise induction of cisplatin resistance in ovarian cancer is more readily acquired in which multiple drug-resistance-associated genes are involved.
Cheng
G
G
Department of Obstetrics and Gynecology, Chinese PLA General Hospital, Chinese Academy of Military Sciences, Beijing 100853, China.
Li
Y
Y
Tian
F
F
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002945:Cisplatin / Q000378:metabolism / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000235:genetics; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics; D009363:Neoplasm Proteins / Q000235:genetics; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured / Q000187:drug effects; D020394:Vault Ribonucleoprotein Particles / Q000235:genetics; D000099187:Major Vault Protein
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D002945:Cisplatin; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; D007527:Isoenzymes; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein; C496556:GSTP1 protein, human