title: Antitumor activity of sorafenib in human cancer cell lines with acquired resistance to EGFR and VEGFR tyrosine kinase inhibitors.
abstract: Treatment of non small cell lung cancer (NSCLC) and colorectal cancer (CRC) have substantially changed in the last years with the introduction of epidermal growth factor receptor (EGFR) inhibitors in the clinical practice. The understanding of mechanisms which regulate cells sensitivity to these drugs is necessary for their optimal use.An in vitro model of acquired resistance to two tyrosine kinase inhibitors (TKI) targeting the EGFR, erlotinib and gefitinib, and to a TKI targeting EGFR and VEGFR, vandetanib, was developed by continuously treating the human NSCLC cell line CALU-3 and the human CRC cell line HCT116 with escalating doses of each drug. MTT, western blot analysis, migration, invasion and anchorage-independent colony forming assays were conducted in vitro and experiments with established xenografts in athymic nude mice were performed in vivo in sensitive, wild type (WT) and TKI-resistant CALU-3 and HCT116 cell lines.As compared to WT CALU-3 and HCT116 human cancer cells, TKI-resistant cell lines showed a significant increase in the levels of activated, phosphorylated AKT, MAPK, and of survivin. Considering the role of RAS and RAF as downstream signals of both the EGFR and VEGFR pathways, we treated resistant cells with sorafenib, an inhibitor of C-RAF, B-RAF, c-KIT, FLT-3, RET, VEGFR-2, VEGFR-3, and PDGFR-β. Sorafenib reduced the activation of MEK and MAPK and caused an inhibition of cell proliferation, invasion, migration, anchorage-independent growth in vitro and of tumor growth in vivo of all TKI-resistant CALU-3 and HCT116 cell lines.These data suggest that resistance to EGFR inhibitors is predominantly driven by the RAS/RAF/MAPK pathway and can be overcame by treatment with sorafenib.
authors.affiliation: Division of Medical Oncology, Department of Clinical and Experimental Medicine and Surgery F Magrassi e A Lanzara Second University of Naples, Naples, Italy. florianamorgillo@yahoo.it
authors.forename: Floriana
authors.initials: F
authors.lastname: Morgillo
authors.forename: Erika
authors.initials: E
authors.lastname: Martinelli
authors.forename: Teresa
authors.initials: T
authors.lastname: Troiani
authors.forename: Michele
authors.initials: M
authors.lastname: Orditura
authors.forename: Ferdinando
authors.initials: F
authors.lastname: De Vita
authors.forename: Fortunato
authors.initials: F
authors.lastname: Ciardiello
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001557:Benzenesulfonates / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D020128:Inhibitory Concentration 50; D051379:Mice; D009361:Neoplasm Invasiveness; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D040262:Receptors, Vascular Endothelial Growth Factor / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D000077157:Sorafenib; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D001557:Benzenesulfonates; D010671:Phenylurea Compounds; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D009536:Niacinamide; D000077157:Sorafenib; D066246:ErbB Receptors; D040262:Receptors, Vascular Endothelial Growth Factor