In vitro evaluation of cisplatin interaction with doxorubicin or 4-hydroperoxycyclophosphamide against human gynecologic cancer cell lines.
Doxorubicin, cisplatin, and cyclophosphamide are the three drugs most commonly used in the treatment of ovarian cancer, but no effect greater than additivity was observed for any combination of these drugs in the present study. Only a few studies have been reported concerning the degree of their additivity or their best order of sequencing. In our in vitro studies, cisplatin in combination with doxorubicin or 4-hydroperoxycyclophosphamide (4HC) was tested against seven human gynecologic tumor-cell lines in different sequences, using a double-agar layer tissue-culture system. Drug interactions with respect to inhibition of tumor clonogenicity were evaluated by isobologram and fractional survival methods. Doxorubicin and 4HC were sequenced simultaneously and at 1, 6 and 24 h after cisplatin, and cisplatin was sequenced at 1, 6 and 24 h after 4HC. The isobolograms constructed for doxorubicin or 4HC plus cisplatin revealed strict additivity between these agents against ovarian cancer clonogenicity. Both doxorubicin and 4HC showed the greatest additivity when used simultaneously and at 1 h vs 6 or 24 h after cisplatin. Although the mechanisms by which these sequencing effects occur are unknown, these studies provide new leads for the design of clinical trials with combinations of these three agents.
Xu
M J
MJ
Department of Medicine, College of Medicine, University of Arizona, Tucson 85724.
Alberts
D S
DS
Liu
R
R
Leibovitz
A
A
Liu
Y
Y
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002460:Cell Line / Q000187:drug effects; D002945:Cisplatin / Q000008:administration & dosage; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000031:analogs & derivatives; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000008:administration & dosage; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D005260:Female; D005833:Genital Neoplasms, Female / Q000188:drug therapy*; D006801:Humans; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014410:Tumor Stem Cell Assay
D004317:Doxorubicin; D003520:Cyclophosphamide; D002945:Cisplatin; C011272:perfosfamide