Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Oncotarget ; 7(22): 32200-9, 2016 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-27058757

RESUMEN

The tumor microenvironment, primarily composed of myofibroblasts, directly influences the progression of solid tumors. Through secretion of growth factors, extracellular matrix deposition, and contractile mechanotransduction, myofibroblasts, or cancer-associated fibroblasts (CAFs), support angiogenesis and cancer cell invasion and metastasis. The differentiation of fibroblasts to CAFs is primarily induced by TGF-ß from cancer cells. To discover agents capable of blocking CAF differentiation, we developed a high content immunofluorescence-based assay to screen repurposed chemical libraries utilizing fibronectin expression as an initial CAF marker. Screening of the Prestwick chemical library and NIH Clinical Collection repurposed drug library, totaling over 1700 compounds, identified cardiac glycosides as particularly potent CAF blocking agents. Cardiac glycosides are traditionally used to regulate intracellular calcium by inhibiting the Na+/K+ ATPase to control cardiac contractility. Herein, we report that multiple cardiac glycoside compounds, including digoxin, are able to inhibit TGF-ß-induced fibronectin expression at low nanomolar concentrations without undesirable cell toxicity. We found this inhibition to hold true for multiple fibroblast cell lines. Using real-time qPCR, we determined that digoxin prevented induction of multiple CAF markers. Furthermore, we report that digoxin is able to prevent TGF-ß-induced fibroblast contraction of extracellular matrix, a major phenotypic consequence of CAF differentiation. Assessing the mechanism of inhibition, we found digoxin reduced SMAD promoter activity downstream of TGF-ß, and we provide data that the effect is through inhibition of its known target, the Na+/K+ ATPase. These findings support a critical role for calcium signaling during CAF differentiation and highlight a novel, repurposable modality for cancer therapy.


Asunto(s)
Antineoplásicos/farmacología , Fibroblastos Asociados al Cáncer/efectos de los fármacos , Glicósidos Cardíacos/farmacología , Diferenciación Celular/efectos de los fármacos , Reposicionamiento de Medicamentos , Miofibroblastos/efectos de los fármacos , Neoplasias de la Próstata/tratamiento farmacológico , Factor de Crecimiento Transformador beta/farmacología , Antineoplásicos/toxicidad , Señalización del Calcio/efectos de los fármacos , Fibroblastos Asociados al Cáncer/metabolismo , Fibroblastos Asociados al Cáncer/patología , Glicósidos Cardíacos/toxicidad , Línea Celular Tumoral , Forma de la Célula/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Fibronectinas/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Miofibroblastos/metabolismo , Miofibroblastos/patología , Regiones Promotoras Genéticas , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Proteínas Smad/genética , Proteínas Smad/metabolismo , Bibliotecas de Moléculas Pequeñas , ATPasa Intercambiadora de Sodio-Potasio/antagonistas & inhibidores , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Transfección , Microambiente Tumoral
2.
Oncotarget ; 7(22): 32664-77, 2016 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-27081699

RESUMEN

c-Met is a receptor tyrosine kinase whose activity can promote both mitogenic and motogenic phenotypes involved in tissue development and cancer progression. Herein, we report the first evidence that c-Met is palmitoylated and that palmitoylation facilitates its trafficking and stability. Inhibition of palmitoylation reduced the expression of c-Met in multiple cancer cell lines post-transcriptionally. Using surface biotinylation, confocal microscopy, and metabolic labeling we determined that inhibition of palmitoylation reduces the stability of newly synthesized c-Met and causes accumulation at the Golgi. Acyl-biotin exchange and click chemistry-based palmitate labeling indicated the c-Met ß-chain is palmitoylated, and site-directed mutagenesis revealed two likely cysteine palmitoylation sites. Moreover, by monitoring palmitoylation kinetics during the biosynthesis and trafficking of c-Met, we revealed that stable palmitoylation occurs in the endoplasmic reticulum prior to cleavage of the 170 kDa c-Met precursor to the mature 140 kDa form. Our data suggest palmitoylation is required for egress from the Golgi for transport to the plasma membrane. These findings introduce palmitoylation as a critical modification of c-Met, providing a novel therapeutic target for c-Met-driven cancers.


Asunto(s)
Proteínas Proto-Oncogénicas c-met/metabolismo , Línea Celular Tumoral , Retículo Endoplásmico/metabolismo , Aparato de Golgi/metabolismo , Humanos , Lipoilación , Transporte de Proteínas , Vías Secretoras , Transducción de Señal
3.
Oncotarget ; 7(22): 32695-706, 2016 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-27127175

RESUMEN

Tumor progression to metastatic disease contributes to the vast majority of incurable cancer. Understanding the processes leading to advanced stage cancer is important for the development of future therapeutic strategies. Here, we establish a connection between tumor cell migration, a prerequisite to metastasis, and monocarboxylate transporter 1 (MCT1). MCT1 transporter activity is known to regulate aspects of tumor progression and, as such, is a clinically relevant target for treating cancer. Knockdown of MCT1 expression caused decreased hepatocyte growth factor (HGF)-induced as well as epidermal growth factor (EGF)-induced tumor cell scattering and wound healing. Western blot analysis suggested that MCT1 knockdown (KD) hinders signaling through the HGF receptor (c-Met) but not the EGF receptor. Exogenous, membrane-permeable MCT1 substrates were not able to rescue motility in MCT1 KD cells, nor was pharmacologic inhibition of MCT1 able to recapitulate decreased cell motility as seen with MCT1 KD cells, indicating transporter activity of MCT1 was dispensable for EGF- and HGF-induced motility. These results indicate MCT1 expression, independent of transporter activity, is required for growth factor-induced tumor cell motility. The findings presented herein suggest a novel function for MCT1 in tumor progression independent of its role as a monocarboxylate transporter.


Asunto(s)
Movimiento Celular/efectos de los fármacos , Factor de Crecimiento Epidérmico/farmacología , Factor de Crecimiento de Hepatocito/farmacología , Transportadores de Ácidos Monocarboxílicos/metabolismo , Simportadores/metabolismo , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Humanos , Ácido Láctico/metabolismo , Transportadores de Ácidos Monocarboxílicos/genética , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Invasividad Neoplásica , Fosforilación , Proteínas Proto-Oncogénicas c-met/metabolismo , Interferencia de ARN , Transducción de Señal , Simportadores/genética , Factores de Tiempo , Transfección
4.
Oncotarget ; 7(21): 31037-52, 2016 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-27105540

RESUMEN

Cancer is a multistep process that requires cells to respond appropriately to the tumor microenvironment, both in early proliferative stages and in later invasive disease. Arl8b is a lysosome localized Arf-like GTPase that controls the spatial distribution of lysosomes via recruitment of kinesin motors. Common features of the tumor microenvironment such as acidic extracellular pH and various growth factors stimulate lysosome trafficking to the cell periphery (anterograde), which is critical for tumor invasion by facilitating the release of lysosomal proteases to promote matrix remodeling. Herein we report for the first time that Arl8b regulates anterograde lysosome trafficking in response to hepatocyte growth factor, epidermal growth factor, and acidic extracellular pH. Depletion of Arl8b results in juxtanuclear lysosome aggregation, and this effect corresponds with both diminished invasive growth and proteolytic extracellular matrix degradation in a three-dimensional model of prostate cancer. Strikingly, we found that depletion of Arl8b abolishes the ability of prostate cancer cells to establish subcutaneous xenografts in mice. We present evidence that Arl8b facilitates lipid hydrolysis to maintain efficient metabolism for a proliferative capacity in low nutrient environments, suggesting a likely explanation for the complete inability of Arl8b-depleted tumor cells to grow in vivo. In conclusion, we have identified two mechanisms by which Arl8b regulates cancer progression: 1) through lysosome positioning and protease release leading to an invasive phenotype and 2) through control of lipid metabolism to support cellular proliferation. These novel roles highlight that Arl8b is a potential target for the development of novel anti-cancer therapeutics.


Asunto(s)
Factores de Ribosilacion-ADP/metabolismo , Neoplasias de la Próstata/enzimología , Factores de Ribosilacion-ADP/genética , Animales , Procesos de Crecimiento Celular/fisiología , Línea Celular Tumoral , Xenoinjertos , Humanos , Masculino , Ratones , Ratones SCID , Invasividad Neoplásica , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Transducción de Señal
5.
Oncotarget ; 6(38): 41180-93, 2015 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-26543230

RESUMEN

The hepatocyte growth factor receptor (HGFR or c-Met) is a driver of multiple cancer subtypes. While there are several c-Met inhibitors in development, few have been approved for clinical use, warranting the need for continued research and development of c-Met targeting therapeutic modalities. The research presented here demonstrates a particular class of compounds known as isothiocyanatostilbenes can act as c-Met inhibitors in multiple cancer cell lines. Specifically, we found that 4,4'-Diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) and 4,4'-Diisothiocyanatodihydrostilbene-2,2'-disulfonic acid (H2DIDS) had c-Met inhibitory effective doses in the low micromolar range while 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) and 4,4'-dinitrostilbene-2, 2'-disulfonic acid (DNDS) exhibited IC50s 100 to 1000 fold higher. These compounds displayed much greater selectivity for inhibiting c-Met activation compared to similar receptor tyrosine kinases. In addition, DIDS and H2DIDS reduced hepatocyte growth factor (HGF)-induced, but not epidermal growth factor (EGF)-induced, cell scattering, wound healing, and 3-dimensional (3D) proliferation of tumor cell spheroids. In-cell and cell-free assays suggested that DIDS and H2DIDS can inhibit and reverse c-Met phosphorylation, similar to SU11274. Additional data demonstrated that DIDS is tolerable in vivo. These data provide preliminary support for future studies examining DIDS, H2DIDS, and derivatives as potential c-Met therapeutics.


Asunto(s)
Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Proteínas Proto-Oncogénicas c-met/metabolismo , Estilbenos/farmacología , Ácido 4,4'-Diisotiocianostilbeno-2,2'-Disulfónico/análogos & derivados , Ácido 4,4'-Diisotiocianostilbeno-2,2'-Disulfónico/farmacología , Ácido 4-Acetamido-4'-isotiocianatostilbeno-2,2'-disulfónico/farmacología , Animales , Western Blotting , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Femenino , Factor de Crecimiento de Hepatocito/farmacología , Humanos , Ratones Desnudos , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Neoplasias/patología , Fosforilación/genética , Factores de Tiempo , Ensayos Antitumor por Modelo de Xenoinjerto
6.
PLoS One ; 9(10): e109208, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25272043

RESUMEN

The presence of reactive stroma, predominantly composed of myofibroblasts, is directly associated with and drives prostate cancer progression. We have previously shown that (-)-Epigallocatechin-3-gallate (EGCG), in the form of Polyphenon E, significantly decreases serum levels of HGF and VEGF in prostate cancer patients. Given that HGF and VEGF are secreted from surrounding tumor myofibroblasts, these observations suggested that EGCG may inhibit prostate cancer-associated myofibroblast differentiation. Herein, we demonstrate that micromolar combinations of EGCG and a second polyphenol, luteolin, synergistically inhibit TGF-ß-induced myofibroblast phenotypes in prostate fibroblast cell lines, as observed primarily by potentiation of fibronectin expression. Functionally, EGCG and luteolin inhibited TGF-ß-induced extracellular matrix contraction, an enhancer of tumor cell invasion. EGCG and luteolin inhibited downstream TGF-ß-induced signaling, including activation of ERK and AKT, respectively, but mechanistically, only ERK appeared to be necessary for TGF-ß-induced fibronectin expression. Furthermore, neither EGCG nor luteolin affected Smad signaling or nuclear translocation. Rho signaling was found to be necessary for TGF-ß-induced fibronectin expression and EGCG and luteolin each reduced RhoA activation. Finally, EGCG and luteolin were shown to reverse TGF-ß-induced fibronectin expression, implicating that these natural compounds may be useful not only in preventing but also in treating already activated myofibroblasts and the diseases they cause, including cancer. The ability of EGCG and luteolin to synergistically target myofibroblasts suggests that combined clinical use of these compounds could prevent or reverse cancer progression through targeting the tumor microenvironment, in addition to the tumor itself.


Asunto(s)
Catequina/análogos & derivados , Quinasas MAP Reguladas por Señal Extracelular/efectos adversos , Luteolina/farmacología , Miofibroblastos/efectos de los fármacos , Factor de Crecimiento Transformador beta/antagonistas & inhibidores , Proteína de Unión al GTP rhoA/efectos adversos , Catequina/farmacología , Línea Celular , Sinergismo Farmacológico , Humanos , Miofibroblastos/citología , Miofibroblastos/metabolismo , Fenotipo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA