RESUMO
Mutations in the kinase domain of the epidermal growth factor receptor (EGFR) were identified in approximately 15% of all patients with non-small cell lung cancer (NSCLC). These mutations have been established as an indicator of superior response to gefitinib and erlotinib, small molecule inhibitors of the EGFR kinase domain. Whether these mutations would also render patients more susceptible to treatment with cetuximab (Erbitux), an EGFR-neutralizing antibody, is yet to be determined. In this study, we attempted to evaluate the effect of cetuximab on several NSCLC lines harboring some of the more common EGFR mutations (L858R and delL747-T753insS), as well as the recently identified kinase inhibitor-resistant mutation, T790M. We could show that the kinase activity of the abovementioned EGFR mutants was hindered by cetuximab, as detected by both cell-based phosphorylation and proliferation assays. Interestingly, cetuximab also induced enhanced degradation of the EGFR mutants as compared with the wild-type receptor. Most importantly, cetuximab successfully inhibited the growth of NSCLC lines in xenograft models. These results indicate the promising potential of cetuximab as a regimen for patients with NSCLC bearing these mutations.
Assuntos
Anticorpos Monoclonais/farmacologia , Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/genética , Receptores ErbB/genética , Neoplasias Pulmonares/genética , Mutação/efeitos dos fármacos , Animais , Anticorpos Monoclonais Humanizados , Apoptose , Western Blotting , Linhagem Celular Tumoral , Cetuximab , Dimerização , Receptores ErbB/metabolismo , Feminino , Imunofluorescência , Humanos , Immunoblotting , Imunoprecipitação , Camundongos , Camundongos Nus , Fosforilação , Inibidores de Proteínas Quinases/farmacologia , Ubiquitina/metabolismoRESUMO
A novel triazole-containing chemical series was shown to inhibit tubulin polymerization and cause cell cycle arrest in A431 cancer cells with EC(50) values in the single digit nanomolar range. Binding experiments demonstrated that representative active compounds of this class compete with colchicine for its binding site on tubulin. The syntheses and structure-activity relationship studies for the triazole derivatives are described herein.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Triazóis/química , Triazóis/farmacologia , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologia , Antineoplásicos/síntese química , Humanos , Microtúbulos/efeitos dos fármacos , Estrutura Molecular , Relação Estrutura-Atividade , Triazóis/síntese química , Moduladores de Tubulina/síntese química , Células Tumorais CultivadasRESUMO
Platelet-derived growth factor receptor alpha (PDGFRalpha) is a type III receptor tyrosine kinase that is expressed on a variety of tumor types. A neutralizing monoclonal antibody to human PDGFRalpha, which did not cross-react with the beta form of the receptor, was generated. The fully human antibody, termed 3G3, has a Kd of 40 pmol/L and blocks both PDGF-AA and PDGF-BB ligands from binding to PDGFRalpha. In addition to blocking ligand-induced cell mitogenesis and receptor autophosphorylation, 3G3 inhibited phosphorylation of the downstream signaling molecules Akt and mitogen-activated protein kinase. This inhibition was seen in both transfected and tumor cell lines expressing PDGFRalpha. The in vivo antitumor activity of 3G3 was tested in human glioblastoma (U118) and leiomyosarcoma (SKLMS-1) xenograft tumor models in athymic nude mice. Antibody 3G3 significantly inhibited the growth of U118 (P=0.0004) and SKLMS-1 (P <0.0001) tumors relative to control. These data suggest that 3G3 may be useful for the treatment of tumors that express PDGFRalpha.