title: Down-regulation of the erbB-2 receptor by trastuzumab (herceptin) enhances tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in breast and ovarian cancer cell lines that overexpress erbB-2.
abstract: We investigated whether combined treatment with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and trastuzumab could enhance the specific killing of cells that overexpress the erbB-2 receptor. The combination resulted in an enhancement of TRAIL-mediated apoptosis in all cell lines overexpressing erbB-2 receptor compared with either reagent alone. In contrast, there was no effect in cell lines with low levels of the erb-B2 receptor. Trastuzumab treatment resulted in down-regulation of the erbB-2 receptor in all erbB-2-overexpressing cell lines. Similar enhancement of TRAIL toxicity was observed when the erbB-2 receptor was down-regulated using antisense oligodeoxynucleotides. Down-regulation of the erbB-2 receptor protein by trastuzumab or antisense oligodeoxynucleotides decreased Akt kinase activation but not mitogen-activated protein kinase activation. Down-regulation of Akt kinase activity by a phosphatidylinositol 3'-kinase inhibitor (LY294002) also resulted in enhancement of TRAIL-mediated apoptosis. Expression of a constitutively active form of Akt kinase in an erbB-2-overexpressing cell line completely abrogated the increase in TRAIL-mediated apoptosis by trastuzumab and significantly reduced the biological effect of either reagent alone. Therefore, down-regulation of the erbB-2 receptor by trastuzumab enhances TRAIL-mediated apoptosis by inhibiting Akt kinase activity. These data suggest that the combination of trastuzumab and TRAIL may allow enhanced therapeutic efficacy and specificity in the treatment of erbB-2-overexpressing tumors.
authors.affiliation: Genetics Department, Medicine Branch, National Cancer Institute, Bethesda, Maryland 20889, USA.
authors.forename: M
authors.initials: M
authors.lastname: Cuello
authors.forename: S A
authors.initials: SA
authors.lastname: Ettenberg
authors.forename: A S
authors.initials: AS
authors.lastname: Clark
authors.forename: M M
authors.initials: MM
authors.lastname: Keane
authors.forename: R H
authors.initials: RH
authors.lastname: Posner
authors.forename: M M
authors.initials: MM
authors.lastname: Nau
authors.forename: P A
authors.initials: PA
authors.lastname: Dennis
authors.forename: S
authors.initials: S
authors.lastname: Lipkowitz
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D015536:Down-Regulation / Q000187:drug effects; D004357:Drug Synergism; D005260:Female; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000494:pharmacology*; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D053221:TNF-Related Apoptosis-Inducing Ligand; D000068878:Trastuzumab; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000494:pharmacology*
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; D000068878:Trastuzumab; D014409:Tumor Necrosis Factor-alpha; C505653:TNFSF10 protein, human; C494918:AKT1 protein, human