title: Synergistic anti-proliferative and pro-apoptotic activity of combined therapy with bortezomib, a proteasome inhibitor, with anti-epidermal growth factor receptor (EGFR) drugs in human cancer cells.
abstract: The proteasome plays a pivotal role in the turnover of regulatory transduction proteins induced by activated cell membrane growth factor receptors. The epidermal growth factor receptor (EGFR) pathway is crucial in the development and progression of human epithelial cancers. Proteasome inhibition may sensitize human cancer cell lines to EGFR inhibitors. We investigated the growth inhibitory and pro-apoptotic effects of the proteasome inhibitor bortezomib in combination with anti-EGFR drugs, such as gefitinib, vandetanib, and cetuximab in EGFR-expressing human cancer cell lines. Bortezomib determined dose-dependent growth inhibition in a nine cancer cell line panel (IC(50) values, range 6-42 nM). A significant synergistic growth inhibitory effect was observed with the combination of bortezomib and each EGFR inhibitor in all cell lines (combination index, CI, range 0.10-0.55), which was accompanied by a significant induction in apoptosis by the combined treatment with bortezomib, cetuximab and vandetanib. In HCT-116 colon cancer and A549 lung adenocarcinoma cells, bortezomib plus EGFR inhibitor treatment induced a more effective inhibition of EGFR-activated down-stream signals, including a marked suppression in activated, phosphorylated Akt (P-Akt). In contrast, overexpression of a constitutively active P-Akt protected A549 cells by cell growth inhibition and apoptosis following treatment with bortezomib and EGFR inhibitors. The combined treatment with bortezomib and EGFR inhibitors has a synergistic growth inhibitory and pro-apoptotic activity in different human cancer cells which possess a functional EGFR-dependent autocrine growth pathway through to a more efficient and sustained inhibition of Akt.
authors.affiliation: Division of Medical Oncology, Department of Clinical and Experimental Medicine and Surgery F. Magrassi and A. Lanzara, Second University of Naples, Naples, Italy.
authors.forename: Tina
authors.initials: T
authors.lastname: Cascone
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Morelli
authors.forename: Floriana
authors.initials: F
authors.lastname: Morgillo
authors.forename: Woo-Young
authors.initials: WY
authors.lastname: Kim
authors.forename: Gabriella
authors.initials: G
authors.lastname: Rodolico
authors.forename: Stefano
authors.initials: S
authors.lastname: Pepe
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Tortora
authors.forename: Liberato
authors.initials: L
authors.lastname: Berrino
authors.forename: Ho-Young
authors.initials: HY
authors.lastname: Lee
authors.forename: John V
authors.initials: JV
authors.lastname: Heymach
authors.forename: Fortunato
authors.initials: F
authors.lastname: Ciardiello
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001897:Boronic Acids / Q000494:pharmacology*; D000069286:Bortezomib; D045744:Cell Line, Tumor / Q000187:drug effects*; D000068818:Cetuximab; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004357:Drug Synergism; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000077156:Gefitinib; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D010880:Piperidines / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D011719:Pyrazines / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D001897:Boronic Acids; D004338:Drug Combinations; D010880:Piperidines; D061988:Proteasome Inhibitors; D011719:Pyrazines; D011799:Quinazolines; D000069286:Bortezomib; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D046988:Proteasome Endopeptidase Complex; D000068818:Cetuximab; D000077156:Gefitinib; C452423:vandetanib