title: Characterization of a novel cell line established from a patient with Herceptin-resistant breast cancer.
abstract: Clinical resistance to the HER-2 oncogene-targeting drug trastuzumab (Herceptin) exists, but studies of the resistance mechanisms are hampered by the lack of suitable experimental model systems. We established a carcinoma cell line (designated JIMT-1) from a pleural metastasis of a 62-year old patient with breast cancer who was clinically resistant to trastuzumab. JIMT-1 cells grow as an adherent monolayer and form xenograft tumors in nude mice. JIMT-1 cells have an amplified HER-2 oncogene, which showed no identifiable mutations in its coding sequence. JIMT-1 cells overexpress HER-2 mRNA and protein, and the levels of HER-1, HER-3, and HER-4 mRNA and protein were similar to the trastuzumab-sensitive cell line SKBR-3. The cell line lacks expression of hormone receptors (estrogen receptors and progesterone receptors) and is phenotypically of epithelial progenitor cell origin, as evidenced by immunohistochemical positivity for both cytokeratins 5/14 and 8/18. JIMT-1 cells were insensitive to trastuzumab and another HER-2-inhibiting drug, pertuzumab (2C4), in vitro and in xenograft tumors. Small molecule tyrosine kinase inhibitors Ci1033 and ZD1839 inhibited the JIMT-1 cell growth but to a lesser degree than in trastuzumab-sensitive BT-474 cells. The lack of growth inhibition was rationalized by the unaltered Akt phosphorylation in JIMT-1 cells. Erk1/2 phosphorylation was slightly reduced but still evident in JIMT-1 cells. We conclude that the JIMT-1 cell line provides a valuable experimental model for studies of new trastuzumab-resistance mechanisms.
authors.affiliation: Laboratory of Cancer Biology, Institute of Medical Technology, University of Tampere and Tampere University Hospital, Tampere, Finland.
authors.forename: Minna
authors.initials: M
authors.lastname: Tanner
authors.forename: Anita I
authors.initials: AI
authors.lastname: Kapanen
authors.forename: Teemu
authors.initials: T
authors.lastname: Junttila
authors.forename: Olayinka
authors.initials: O
authors.lastname: Raheem
authors.forename: Seija
authors.initials: S
authors.lastname: Grenman
authors.forename: Jussi
authors.initials: J
authors.lastname: Elo
authors.forename: Klaus
authors.initials: K
authors.lastname: Elenius
authors.forename: Jorma
authors.initials: J
authors.lastname: Isola
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D001943:Breast Neoplasms / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation; D010997:Pleural Neoplasms / Q000188:drug therapy / Q000276:immunology / Q000556:secondary; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D066247:Receptor, ErbB-4; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism / Q000473:pathology; D014183:Transplantation, Heterologous; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger; D018719:Erb-b2 Receptor Tyrosine Kinases; D066247:Receptor, ErbB-4; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D000068878:Trastuzumab; C587689:ERBB4 protein, human; C587690:Erbb4 protein, mouse; C494918:AKT1 protein, human; C485206:pertuzumab