title: Mitoxantrone resistance in a small cell lung cancer cell line is associated with ABCA2 upregulation.
abstract: The aim of this study was to find factors that could explain the accumulation difference of mitoxantrone in the BCRP1-negative GLC4-MITO cell line compared to GLC4. Comparative genomic hybridisation (CGH) was applied to determine chromosomal differences between GLC4 and GLC4-MITO. Comparative genomic hybridisation analysis revealed gain of 2q, 6p, 9q, 13q, 14q, 15q, 19q and Xp and loss of 1p, 2q, 3p, 3q, 4q, 6q, 8q, 11p, 16p, 17q, 18p, 20p and Xq. In the over-represented chromosomal areas, seven transporter genes were identified: ABCB6, ABCB2 (TAP1), ABCB3 (TAP2), ABCF1 (ABC50), ABCC10 (MRP7), ABCA2 (ABC2) and ABCC4 (MRP4). No RNA or protein upregulation was observed for ABCB6, ABCF1, ABCC10, ABCC4, ABCB2 and ABCB3, but an increased expression was detected for ABCA2 mRNA in GLC4-MITO. ABCA2 is known to be involved in resistance to estramustine. In the MTT assay, GLC4-MITO was two-fold resistant to estramustine compared to GLC4. Coincubation with estramustine and mitoxantrone increased mitoxantrone accumulation in GLC4-MITO, while this was not affected in GLC4. This suggests that estramustine is able to block mitoxantrone efflux in GLC4-MITO cells. These data reveal that cellular reduction of mitoxantrone in a mitoxantrone-resistant cell line is associated with overexpression of ABCA2.
authors.affiliation: Department of Pathology and Laboratory Medicine, University Hospital Groningen, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Boonstra
authors.forename: H
authors.initials: H
authors.lastname: Timmer-Bosscha
authors.forename: J
authors.initials: J
authors.lastname: van Echten-Arends
authors.forename: D M
authors.initials: DM
authors.lastname: van der Kolk
authors.forename: A
authors.initials: A
authors.lastname: van den Berg
authors.forename: B
authors.initials: B
authors.lastname: de Jong
authors.forename: K D
authors.initials: KD
authors.lastname: Tew
authors.forename: S
authors.initials: S
authors.lastname: Poppema
authors.forename: E G E
authors.initials: EG
authors.lastname: de Vries
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D018288:Carcinoma, Small Cell / Q000188:drug therapy* / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D008942:Mitoxantrone / Q000494:pharmacology*; D009693:Nucleic Acid Hybridization; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: C418186:ABCA2 protein, human; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D008942:Mitoxantrone