title: Imatinib mesylate inhibits platelet-derived growth factor activity and increases chemosensitivity in feline vaccine-associated sarcoma.
abstract: Feline vaccine-associated sarcoma (VAS) is a biologically aggressive soft-tissue sarcoma that can develop at sites where inactivated feline vaccines have been administered. We showed that platelet-derived growth factor (PDGF) and its receptor (PDGFR) play a role in the growth of VAS cells. The presence of PDGFR-beta was confirmed in each of five VAS cell lines evaluated, one non-vaccine-associated feline fibrosarcoma (FSA) cell line and a feline fibroblast-derived cell line. The PDGF/PDGFR signaling pathway was inhibited in the VAS cell lines and the FSA cell line using the tyrosine kinase inhibitor imatinib mesylate (formerly called STI-571). Imatinib inhibited PDGF-BB-induced autophosphorylation of PDGFR in VAS cells and feline FSA cells in vitro in a dose-dependent manner. Imatinib also significantly inhibited growth of feline VAS tumors in a murine xenograft model. Imatinib reversed the protective effect of PDGF-BB on growth inhibition by doxorubicin and carboplatin. PDGF-BB protected VAS cells from serum starvation and doxorubicin-induced apoptosis but not carboplatin-induced apoptosis, and imatinib eliminated this protection. These observations suggest that imatinib inhibits PDGFR tyrosine kinase activity in feline soft tissue sarcomas in vitro and inhibits tumor growth in a xenograft model.
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive West, Madison, WI 53706, USA.
authors.forename: Rieko
authors.initials: R
authors.lastname: Katayama
authors.forename: Michael K
authors.initials: MK
authors.lastname: Huelsmeyer
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Marr
authors.forename: Ilene D
authors.initials: ID
authors.lastname: Kurzman
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Thamm
authors.forename: David M
authors.initials: DM
authors.lastname: Vail
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D001549:Benzamides; D002371:Cat Diseases / Q000188:drug therapy* / Q000473:pathology; D002415:Cats; D000068877:Imatinib Mesylate; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental; D010879:Piperazines / Q000494:pharmacology*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D017479:Receptors, Platelet-Derived Growth Factor / Q000187:drug effects* / Q000502:physiology*; D012509:Sarcoma / Q000188:drug therapy* / Q000473:pathology / Q000662:veterinary*; D015398:Signal Transduction; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D014612:Vaccines / Q000009:adverse effects
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D010982:Platelet-Derived Growth Factor; D011743:Pyrimidines; D014612:Vaccines; D000068877:Imatinib Mesylate; C099852:PDGF receptor tyrosine kinase; D017479:Receptors, Platelet-Derived Growth Factor