Characterization of an Ovarian Carcinoma Cell Line Resistant to Cisplatin and Flavopiridol

• Published in: Clinical cancer research Vol. 6; no. 2; pp. 661 - 670
• Main Authors: Keith C. Bible, Scott A. Boerner, Kathryn Kirkland, Kari L. Anderl, Duane Bartelt, Jr, Phyllis A. Svingen, Timothy J. Kottke, Yean K. Lee, Steven Eckdahl, Paul G. Stalboerger, Robert B. Jenkins, Scott H. Kaufmann
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 01-02-2000
• Subjects: Antineoplastic agents; Antineoplastic Agents - toxicity; Biological and medical sciences; Carmustine - toxicity; Chromosome Aberrations; Chromosome Mapping; Cisplatin - pharmacokinetics; Cisplatin - toxicity; DNA Adducts - analysis; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Female; Flavonoids - toxicity; General aspects; Humans; Karyotyping; Medical sciences; Organoplatinum Compounds - pharmacokinetics; Organoplatinum Compounds - toxicity; Ovarian Neoplasms - genetics; Ovarian Neoplasms - pathology; Pharmacology. Drug treatments; Piperidines - toxicity; Tumor Cells, Cultured; Antineoplastic agent; Carcinoma; Enzyme; Transferases; Enzyme inhibitor; Malignant tumor; In vitro; Cisplatin; Female genital diseases; Characterization; Resistance; Ovarian diseases; Ovary; Protein kinase; Established cell line; Mechanism of action; Tumor cell; Platinum II Complexes
• ISSN: 1078-0432; 1557-3265

Flavopiridol,
the first inhibitor of cyclin-dependent kinases to enter
clinical trials, has shown promising antineoplastic activity and is
currently undergoing Phase II testing. Little is known about mechanisms
of resistance to this agent. In the present study, we have
characterized an ovarian carcinoma cell line [OV202 high passage
(hp)] that spontaneously developed drug resistance upon
prolonged passage in tissue culture. Standard cytogenetic analysis and
spectral karyotyping revealed that OV202 hp and the parental low
passage line OV202 shared several marker chromosomes, confirming the
relatedness of these cell lines. Immunoblotting demonstrated that OV202
and OV202 hp contained similar levels of a variety of polypeptides
involved in cell cycle regulation, including cyclin-dependent kinases 2
and 4; cyclins A, D 1 , and E; and proliferating cell nuclear
antigen. Despite these similarities, OV202 hp was resistant to
flavopiridol and cisplatin, with increases of 5- and 3-fold,
respectively, in the mean drug concentrations required to inhibit
colony formation by 90%. In contrast, OV202 hp and OV202 displayed
indistinguishable sensitivities to oxaliplatin, paclitaxel, topotecan,
1,3-bis(2-chloroethyl)-1-nitrosourea, etoposide, doxorubicin,
vincristine, and 5-fluorouracil, suggesting that the spontaneously
acquired resistance was not attributable to altered P-glycoprotein
levels or a general failure to engage the cell death machinery. After
incubation with cisplatin, whole cell platinum and platinum-DNA
adducts measured using mass spectrometry were lower in OV202 hp cells
than OV202 cells. Similarly, after flavopiridol exposure, whole cell
flavopiridol concentrations measured by a newly developed high
performance liquid chromatography assay were lower in OV202 hp cells.
These data are consistent with the hypothesis that acquisition of
spontaneous resistance to flavopiridol and cisplatin in OV202 hp cells
is due, at least in part, to reduced accumulation of the respective
drugs. These observations not only provide the first characterization
of a flavopiridol-resistant cell line but also raise the possibility
that alterations in drug accumulation might be important in determining
sensitivity to this agent.