title: Carboplatin treatment of antiestrogen-resistant breast cancer cells.
abstract: Antiestrogen resistance is a major clinical problem in current breast cancer             treatment. Therefore, biomarkers and new treatment options for antiestrogen-resistant             breast cancer are needed. In this study, we investigated whether antiestrogen‑resistant             breast cancer cell lines have increased sensitivity to carboplatin, as it was             previously shown with cisplatin, and whether low Bcl-2 expression levels have             a potential value as marker for increased carboplatin sensitivity. Breast cancer             cells resistant to the pure antiestrogen fulvestrant, and two out of four cell             lines resistant to the antiestrogen tamoxifen, were more sensitive to carboplatin             treatment compared to the parental MCF-7 cell line. This indicates that carboplatin             may be an advantageous treatment in antiestrogen‑resistant breast cancer; however,             a marker for increased sensitivity would be needed. Low Bcl-2 expression was correlated             with increased carboplatin response in the tamoxifen‑resistant cell line MCF-7/TAMR-1             and overexpression of Bcl-2 in this cell line resulted in significantly reduced             carboplatin sensitivity, confirming the anti-apoptotic role of Bcl-2. However,             neither Bcl-2 expression alone, nor Bcl-2 in combination with Bcl-xL and Bax,             could explain the observed responses to carboplatin in all tamoxifen‑resistant             cell lines, indicating that more markers are needed to predict the response to             carboplatin in tamoxifen‑resistant breast cancer.
authors.affiliation: Breast Cancer Group, Unit of Cell Death and Metabolism, Danish                     Cancer Society Research Center, DK-2100 Copenhagen Ø, Denmark.
authors.forename: Mathilde S
authors.initials: MS
authors.lastname: Larsen
authors.forename: Christina W
authors.initials: CW
authors.lastname: Yde
authors.forename: Ib J
authors.initials: IJ
authors.lastname: Christensen
authors.forename: Anne E
authors.initials: AE
authors.lastname: Lykkesfeldt
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism; D016190:Carboplatin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology*; D005260:Female; D000077267:Fulvestrant; D015870:Gene Expression; D006801:Humans; D061986:MCF-7 Cells; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D013629:Tamoxifen / Q000494:pharmacology; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D018931:Antineoplastic Agents, Hormonal; D004965:Estrogen Antagonists; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D013629:Tamoxifen; D000077267:Fulvestrant; D004958:Estradiol; D016190:Carboplatin