title: Establishment of a 7-ethyl-10-hydroxy-camptothecin-resistant small cell lung cancer cell line.
abstract: Irinotecan is one of the most active drugs used in the treatment of small cell lung cancer (SCLC). 7-Ethyl-10-hydroxy-camptothecin (SN-38) is an active metabolite of irinotecan. We established an SN-38-resistant subline (SBC-3/SN-38) by continuous exposure of SN-38 to a human SCLC cell line, SBC-3. Using the 3-[4, 5-dimethyl-thiazol-2-yl] 2, 5-diphenyltetrazolium bromide assay, we evaluated the cytotoxicity of 17 anticancer agents. The SBC-3/SN-38 cells were 73-fold more resistant than the parental SBC-3 cells to SN-38 and showed cross-resistance not only to topoisomerase (topo) I inhibitors (irinotecan and topotecan), but also to topo II inhibitors (adriamycin and etoposide), antimicrotubule agents (vincristine, vindesine, vinorelbine and docetaxel), alkylating agents (cyclophosphamide and ifosfamide), platinum (cisplatin and carboplatin) and antifolate (methotrexate). Interestingly, the resistant subline reserved the sensitivity to bleomycin and 5-fluorouracil. The SBC-3/SN-38 cells had decreased topo I and II activity compared to the parent cells. The SN-38-resistant cell line, SBC-3/SN-38, will be useful to elucidate the mechanism of action of the topo I inhibitors.
authors.affiliation: Second Department of Internal Medicine, Okayama University Medical School, Division of Thoracic Oncology, Okayama University Hospital, 2-5-1 Shikata-cho, Okayama 700-8558, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Chikamori
authors.forename: Nagio
authors.initials: N
authors.lastname: Takigawa
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Kiura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tabata
authors.forename: Takuo
authors.initials: T
authors.lastname: Shibayama
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Segawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ueoka
authors.forename: Taisuke
authors.initials: T
authors.lastname: Ohnoshi
authors.forename: Mitsune
authors.initials: M
authors.lastname: Tanimoto
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D018288:Carcinoma, Small Cell / Q000188:drug therapy* / Q000473:pathology*; D045744:Cell Line, Tumor; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D000077146:Irinotecan; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000473:pathology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D000077146:Irinotecan; D002166:Camptothecin