title: Combinatorial synergy induced by adenoviral-mediated mda-7 and Herceptin in Her-2+ breast cancer cells.
abstract: The melanoma differentiation-associated gene-7 (mda-7) is a member of the interleukin-10 cytokine family and a novel tumor suppressor gene. Adenoviral-mediated mda-7 (Ad-mda7) gene transfer has tumor-specific growth inhibitory and proapoptotic effects in a broad spectrum of cancer cells. In breast cancer cells, adenoviral-induced mda-7 expression triggers antiproliferative effects by downregulation of survival signals, such as Bcl-2 and Akt. The anti-human epidermal growth factor receptor-2 (Her-2) monoclonal antibody, Trastuzumab (Herceptin), increases the sensitivity of Her-2/neu-overexpressing breast cancer cells to chemotherapeutic agents and radiotherapy. In this study, we evaluate the effects of treatment with Ad-mda7 and Herceptin combination therapy in a panel of Her-2/neu-overexpressing cell lines, and in established tumors in nude mice. Compared to individual treatments, the combination of Ad-mda7 and Herceptin elicits supra-additive antitumor activity in Her-2/neu-overexpressing tumor cell lines: increased cell death, cell cycle block and apoptosis. The Ad-mda7 and Herceptin interaction was shown to be synergistic by isobologram analysis. Ad-mda7 does not alter cell surface Her-2/neu levels, but the combination of Ad-mda7+Herceptin results in increased expression of cell surface E-cadherin with concomitant translocation of beta-catenin from the nucleus to the cell membrane. In vivo, the combination of Ad-mda7 and Herceptin showed significantly increased antitumor activity (P<0.003) against Her-2/neu-overexpressing tumors. These data suggest that the combination of Ad-mda7 with Herceptin may be a novel therapy for breast cancer patients whose tumors overexpress Her-2/neu. The observed synergistic effect may improve treatment options for otherwise poorly responsive, Her-2-positive, breast cancer patients.
authors.affiliation: Introgen Therapeutics Inc., Houston, TX 77030, USA.
authors.forename: D
authors.initials: D
authors.lastname: Bocangel
authors.forename: M
authors.initials: M
authors.lastname: Zheng
authors.forename: A
authors.initials: A
authors.lastname: Mhashilkar
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Ramesh
authors.forename: K K
authors.initials: KK
authors.lastname: Hunt
authors.forename: S
authors.initials: S
authors.lastname: Chada
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics*; D061067:Antibodies, Monoclonal, Humanized; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005455:Fluorescent Antibody Technique; D005822:Genetic Vectors; D006801:Humans; D007378:Interleukins / Q000235:genetics*; D051379:Mice; D008819:Mice, Nude; D000068878:Trastuzumab; D000099180:Interleukin-24
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D007378:Interleukins; D000068878:Trastuzumab; D000099180:Interleukin-24