RESUMEN
Chondrosarcoma is a malignant primary bone tumor that responds poorly to both chemotherapy and radiation therapy. This study is the first to investigate the anti-cancer effects of the new benzimidazole derivative (5-methyl-2(pyridine-3-yl)-1-(3,4,5-trimethoxybenzyl)benzimidazole; MPTB) in human chondrosarcoma cells. MPTB-induced cell apoptosis in two human chondrosarcoma cell lines, JJ012 and SW1353 but not in primary chondrocytes. MPTB-induced upregulation of Bax and Bak and dysfunction of mitochondria in chondrosarcoma. MPTB triggered endoplasmic reticulum (ER) stress, as indicated by changes in cytosol calcium levels, and increased glucose-regulated protein (GRP) expression. MPTB also increased calpain expression. Transfection of cells with GRP78 or calpain siRNA reduced MPTB-mediated cell apoptosis in JJ012 cells. Importantly, animal studies have revealed a dramatic 44% reduction in tumor volume after 21 d of treatment. This study demonstrates novel anti-cancer activity of MPTB against human chondrosarcoma cells and in murine tumor models.
Asunto(s)
Apoptosis/efectos de los fármacos , Bencimidazoles/farmacología , Condrosarcoma/tratamiento farmacológico , Ensayos Antitumor por Modelo de Xenoinjerto , Animales , Bencimidazoles/química , Western Blotting , Calpaína/genética , Calpaína/metabolismo , Caspasas/metabolismo , Línea Celular Tumoral , Células Cultivadas , Condrosarcoma/genética , Condrosarcoma/patología , Relación Dosis-Respuesta a Droga , Chaperón BiP del Retículo Endoplásmico , Citometría de Flujo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Masculino , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Ratones SCID , Estructura Molecular , Interferencia de ARN , Carga Tumoral/efectos de los fármacos , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismo , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Invasion of tumor cells is the primary cause of therapeutic failure in malignant chondrosarcomas treatment. Receptor activator of nuclear factor-kappaB ligand (RANKL) and its receptor, RANK, play a key roles in osteoclastogenesis and tumor metastasis. We found that the RANKL and RANK expression in human chondrosarcoma tissues was higher than that in normal cartilage. We also found that RANKL directed the migration and increased cell surface expression of beta1 integrin in human chondrosarcoma cells (JJ012 cells). Pretreatment of JJ012 cells with MAPK kinase (MEK) inhibitors, PD98059 or U0126, inhibited the RANKL-induced migration and integrin expression. Stimulation of cells with RANKL increased the phosphorylation of MEK and extracellular signal-regulating kinase (ERK). In addition, NF-kappaB inhibitor (PDTC) or IkappaB protease inhibitor (TPCK) also inhibited RANKL-induced cells migration and integrin up-regulation. Taken together, these results suggest that the RANKL acts through MEK/ERK, which in turn activates IKKalpha/beta and NF-kappaB, resulting in the activation of beta1 integrin and contributing to the migration of human chondrosarcoma cells.