title: Isolation and characterization of an IGROV-1 human ovarian cancer cell line made resistant to Ecteinascidin-743 (ET-743).
abstract: By exposing Igrov-1 human ovarian cancer cells to increasing concentrations of Ecteinascidin-743 (ET-743), either for a short or prolonged time, we obtained sublines resistant to ET-743 which overexpress Pgp. The most resistant clone (Igrov-1/25 ET) was evaluated for biological and pharmacological characterizations. The increased Pgp levels of Igrov-1/25 ET were not due to amplification of the mdr-1 gene but to increased mRNA levels. No increase in other multidrug resistance-related proteins such as MRP or LRP was observed in Igrov-1/25 ET. The IC50 values of ET-743 against Igrov-1/25 ET was approximately 50 times higher than the parental cell line. Resistance was not reversed while maintaining the cell line in drug-free medium for at least 24 months. Igrov-1/25 ET was cross-resistant to Doxorubicin and VP16 while it was equally sensitive to L-PAM, MNNG, CPT and only marginally less sensitive to Cis-DDP and Oxaliplatin compared to the parental cell line. Igrov-1/25 ET exposed to Doxorubicin retained this drug much less, mainly because of a more efficient drug efflux. The cyclosporine analogue SDZ PSC-833 reversed the resistance of Igrov-1/25 ET to ET-743, without any enhancement of the drug activity against the parental Igrov-1 cell line. Igrov-1/25 ET exhibits typical features of cell lines overexpressing the mdr-1 gene and can be a potentially useful tool in selecting ET-743 non-cross-resistant analogues as well as to investigate methods to counteract resistance to this drug.
authors.affiliation: Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Erba
authors.forename: D
authors.initials: D
authors.lastname: Bergamaschi
authors.forename: L
authors.initials: L
authors.lastname: Bassano
authors.forename: S
authors.initials: S
authors.lastname: Ronzoni
authors.forename: G
authors.initials: G
authors.lastname: Di Liberti
authors.forename: I
authors.initials: I
authors.lastname: Muradore
authors.forename: S
authors.initials: S
authors.lastname: Vignati
authors.forename: G
authors.initials: G
authors.lastname: Faircloth
authors.forename: J
authors.initials: J
authors.lastname: Jimeno
authors.forename: M
authors.initials: M
authors.lastname: D'Incalci
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000903:Antibiotics, Antineoplastic / Q000493:pharmacokinetics; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D004149:Dioxoles / Q000494:pharmacology*; D004317:Doxorubicin / Q000493:pharmacokinetics; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005260:Female; D005434:Flow Cytometry; D019450:Genes, MDR; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology*; D009363:Neoplasm Proteins / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology; D044005:Tetrahydroisoquinolines; D000077606:Trabectedin; D014407:Tumor Cells, Cultured / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D020394:Vault Ribonucleoprotein Particles / Q000378:metabolism; D000099187:Major Vault Protein
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D018906:Antineoplastic Agents, Alkylating; D004149:Dioxoles; D004317:Doxorubicin; D007546:Isoquinolines; D009363:Neoplasm Proteins; D044005:Tetrahydroisoquinolines; D000077606:Trabectedin; D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein