RESUMEN
Wnt signaling pathway plays a critical role in numerous cellular processes, including tumor initiation, proliferation, invasion/infiltration, metastasis formation and resistance to chemotherapy. In a drug discovery project aimed at the identification of inhibitors of the canonical Wnt pathway, we selected a series of quinazoline 2,4-diones as starting point for the therapeutic treatment of glioblastoma multiforme. Despite of poor physico-chemical properties of hit compound 1, our medicinal chemistry effort allowed the discovery and characterization of lead compound 33 (SEN461), with improved ADME profile, good bioavailability and active in vitro and in vivo in glioblastoma, gastric and sarcoma tumors.
Asunto(s)
Antineoplásicos/química , Antineoplásicos/farmacología , Quinazolinas/química , Quinazolinas/farmacología , Vía de Señalización Wnt/efectos de los fármacos , Animales , Antineoplásicos/metabolismo , Antineoplásicos/farmacocinética , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Femenino , Humanos , Concentración 50 Inhibidora , Masculino , Ratones , Quinazolinas/metabolismo , Quinazolinas/farmacocinética , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Sarcomas are mesenchymal tumors showing high molecular heterogeneity, reflected at the histological level by the existence of more than fifty different subtypes. Genetic and epigenetic evidences link aberrant activation of the Wnt signaling to growth and progression of human sarcomas. This phenomenon, mainly accomplished by autocrine loop activity, is sustained by gene amplification, over-expression of Wnt ligands and co-receptors or epigenetic silencing of endogenous Wnt antagonists. We previously showed that pharmacological inhibition of Wnt signaling mediated by Axin stabilization produced in vitro and in vivo antitumor activity in glioblastoma tumors. Here, we report that targeting different sarcoma cell lines with the Wnt inhibitor/Axin stabilizer SEN461 produces a less transformed phenotype, as supported by modulation of anchorage-independent growth in vitro. At the molecular level, SEN461 treatment enhanced the stability of the scaffold protein Axin1, a key negative regulator of the Wnt signaling with tumor suppressor function, resulting in downstream effects coherent with inhibition of canonical Wnt signaling. Genetic phenocopy of small molecule Axin stabilization, through Axin1 over-expression, coherently resulted in strong impairment of soft-agar growth. Importantly, sarcoma growth inhibition through pharmacological Axin stabilization was also observed in a xenograft model in vivo in female CD-1 nude mice. Our findings suggest the usefulness of Wnt inhibitors with Axin stabilization activity as a potentialyl clinical relevant strategy for certain types of sarcomas.
Asunto(s)
Antineoplásicos/farmacología , Proteína Axina/metabolismo , Sarcoma/fisiopatología , Vía de Señalización Wnt/fisiología , Animales , Línea Celular Tumoral , Cartilla de ADN/genética , Femenino , Técnica del Anticuerpo Fluorescente , Vectores Genéticos/genética , Humanos , Immunoblotting , Lentivirus , Ratones , Ratones Desnudos , Microscopía Confocal , Plásmidos/genética , Estabilidad Proteica/efectos de los fármacos , Reacción en Cadena en Tiempo Real de la Polimerasa , Sarcoma/tratamiento farmacológicoRESUMEN
Glioblastoma multiforme (GBM) is composed of heterogeneous and genetically different cells, which are highly invasive and motile. The standard chemotherapeutic agent, temozolomide, affects GBM cell proliferation but is generally unable to prevent tumor recurrence. Hedgehog pathway activation has been reported to be relevant in GBM and different pharmacological pathway modulators have been identified. We report that by growing a commercially available recurrent GBM cell line (DBTRG-05MG) without serum and in the presence of defined growth factors; we obtained a less differentiated cell population, growing in suspension as neurospheres, in which the Hedgehog pathway is activated. Furthermore, the expression profile of Hedgehog pathway components found in DBTRG-05MG neurospheres is similar to primary stem-like cells derived from recurrent GBM patients. We report the effect of our novel specific Smoothened receptor antagonist (SEN450) on neurosphere growing cells and compared its effect to that of well known benchmark compounds. Finally, we showed that SEN450 is both antiproliferative on its own and further reduces tumor volume after temozolomide pretreatment in a mouse xenograft model using DBTRG-05MG neurosphere cells. Altogether our data indicate that the Hedgehog pathway is not irreversibly switched off in adherent cells but can be reactivated when exposed to well-defined culture conditions, thus restoring the condition observed in primary tumor-derived material, and that pharmacological modulation of this pathway can have profound influences on tumor proliferation. Therefore, pharmacological inhibition of the Hedgehog pathway is a potentially useful therapeutic approach in GBM.