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ID 32669
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Author
Takigawa, Nagio
Ohnoshi, Taisuke
Ueoka, Hiroshi
Kimura, Ikuro
Abstract

An etoposide-resistant subline, SBC-3/ETP, from a human small cell lung cancer cell line, SBC-3, was developed by continuous exposure to increasing concentrations of etoposide in culture. The SBC-3/ETP was 52.1-fold more resistant to etoposide than the parent cell line. The SBC-3/ETP was highly cross-resistant to teniposide, adriamycin, vinca alkaloids, 4-hydroperoxycyclophosphamide, CPT-11 and mitomycin C, and marginally cross-resistant to cisplatin, while the subline showed a collateral sensitivity to bleomycin. Topoisomerase I activity in the SBC-3/ETP was reduced to an extent of one half and topoisomerase II activity to an extent of one eighth in comparison with those of the SBC-3. Intracellular accumulation of [3H]-etoposide in the SBC-3/ETP was significantly lower in comparison to the SBC-3. An overexpression of MDR1 mRNA, and the presence of its product, P-glycoprotein, were detected in the SBC-3/ETP by Northern blotting and flowcytometry using a monoclonal antibody of the protein, MRK16. These results indicate that a decreased activity of topoisomerase II is the major factor for the development of etoposide resistance, and that an overexpression of the MDR1 gene is responsible, in part, for the development of resistance to the drug and some structurally unrelated compounds such as adriamycin and vinca alkaloids.

Keywords
small cell lung cancer
etoposide-resistant cell line
P-glycoprotein
topoisomerase
Amo Type
Article
Published Date
1992-06
Publication Title
Acta Medica Okayama
Volume
volume46
Issue
issue3
Publisher
Okayama University Medical School
Start Page
203
End Page
212
ISSN
0386-300X
NCID
AA00508441
Content Type
Journal Article
language
英語
File Version
publisher
Refereed
True
PubMed ID
Web of Science KeyUT