title: Characterization of a novel, trastuzumab resistant human breast cancer cell line.
abstract: HER2-positive breast cancers represent a distinct phenotype and are intrinsically more aggressive than HER2-negative tumors. Although HER2-targeted therapies have been rationally developed, resistance to these treatments represents a process understood poorly. There are few experimental models that allow studying the molecular mechanism of resistance. Our aim was to characterize a trastuzumab resistant breast cancer cell line (B585) that was established from an invasive ductal carcinoma. B585 grows only in immunodeficient mice as a xenograft. CGH and FISH were used to define cytogenetic alterations, gene-expression analysis and immunohistochemistry were applied to detect RNA and protein expression. By array-CGH focused amplifications were identified for C-MYC, EGFR, ErbB2, CCND1 and TOP2-A oncogenes. ErbB2 was co-amplified with TOP2-A. mRNA overexpression was detected for the amplified genes. ErbB2 protein was overexpressed and showed heterogeneous distribution. In summary, molecular cytogenetic analysis and expression profiling of B585 revealed several new alterations. Based on the experiments performed in SCID mice and the genotypic/phenotypic characteristics, this new in vivo breast cancer xenograft is a valuable model to investigate molecular mechanism of trastuzumab resistance.
authors.affiliation: Department of Biophysics and Cell Biology, Faculty of Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: Mark
authors.initials: M
authors.lastname: Barok
authors.forename: Margit
authors.initials: M
authors.lastname: Balazs
authors.forename: Viktoria
authors.initials: V
authors.lastname: Lazar
authors.forename: Zsuzsa
authors.initials: Z
authors.lastname: Rakosy
authors.forename: Eniko
authors.initials: E
authors.lastname: Toth
authors.forename: Andrea
authors.initials: A
authors.lastname: Treszl
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Vereb
authors.forename: Gail T
authors.initials: GT
authors.lastname: Colbern
authors.forename: John W
authors.initials: JW
authors.lastname: Park
authors.forename: Janos
authors.initials: J
authors.lastname: Szollosi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy*; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy*; D045744:Cell Line, Tumor; D055028:Comparative Genomic Hybridization; D004195:Disease Models, Animal; D019008:Drug Resistance, Neoplasm; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D051379:Mice; D016513:Mice, SCID; D009857:Oncogenes / Q000235:genetics; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human