RESUMEN
Transcriptional co-activator with PSD-95/Dlg-A/ZO-1 (PDZ)-binding motif (TAZ) regulates in cell proliferation and differentiation. In mesenchymal stem cells it promotes osteogenesis and myogenesis, and suppresses adipogenesis. TAZ activators are expected to prevent osteoporosis, obesity and muscle atrophy. TAZ activation induces epithelial-mesenchymal transition, confers stemness to cancer cells and leads to poor clinical prognosis in cancer patients. In this point of view, TAZ inhibitors should contribute to cancer therapy. Thus, TAZ attracts attention as a two-faced drug target. We screened for TAZ modulators by using human lung cancer A549 cells expressing the fluorescent reporter. Through this assay, we obtained TAZ activator candidates. We unexpectedly found that ethacridine, a widely used antiseptic and abortifacient, enhances the interaction of TAZ and protein phosphatases and increases unphosphorylated and nuclear TAZ. Ethacridine inhibits adipogenesis in mesenchymal C3H10T1/2 cells through the activation of TAZ. This finding suggests that ethacridine is a bona fide TAZ activator and supports that our assay is useful to discover TAZ activators.
Asunto(s)
Adipogénesis/efectos de los fármacos , Fármacos Antiobesidad/farmacología , Etacridina/farmacología , Péptidos y Proteínas de Señalización Intracelular/agonistas , Células Madre Mesenquimatosas/efectos de los fármacos , Proteína Fosfatasa 1/metabolismo , Proteína Fosfatasa 2/metabolismo , Transporte Activo de Núcleo Celular/efectos de los fármacos , Proteínas Adaptadoras Transductoras de Señales/agonistas , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Línea Celular Tumoral , Evaluación Preclínica de Medicamentos , Genes Reporteros/efectos de los fármacos , Células HEK293 , Humanos , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/metabolismo , Fosfoproteínas/agonistas , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilación/efectos de los fármacos , Regiones Promotoras Genéticas/efectos de los fármacos , Proteína Fosfatasa 1/química , Proteína Fosfatasa 1/genética , Proteína Fosfatasa 2/química , Proteína Fosfatasa 2/genética , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Interferencia de ARN , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Transactivadores , Factores de Transcripción , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ , Proteínas Supresoras de Tumor/antagonistas & inhibidores , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Proteínas Señalizadoras YAPRESUMEN
The activation of sterol regulatory element binding proteins (SREBPs) is regulated by insulin-induced genes 1 and 2 (Insig-1 and Insig-2) and SCAP. We previously reported that feeding R-α-lipoic acid (LA) to Zucker diabetic fatty (ZDF) rats improves severe hypertriglyceridemia. In this study, we investigated the role of cyclic AMP-responsive element binding protein H (CREBH) in the lipid-lowering mechanism of LA and its involvement in the SREBP-1c and Insig pathway. Incubation of McA cells with LA (0.2 mM) or glucose (6 mM) stimulated activation of CREBH. LA treatment further induced mRNA expression of Insig-1 and Insig-2a, but not Insig-2b, in glucose-treated cells. In vivo, feeding LA to obesity-induced hyperlipidemic ZDF rats activated hepatic CREBH and stimulated transcription and translation of Insig-1 and Insig-2a. Activation of CREBH and Insigs induced by LA suppressed processing of SREBP-1c precursor into nuclear SREBP-1c, which subsequently inhibited expression of genes involved in fatty acid synthesis, including FASN, ACC and SCD-1, and reduced triglyceride (TG) contents in both glucose-treated cells and ZDF rat livers. Additionally, LA treatment also decreased abundances of very low density lipoprotein (VLDL)-associated apolipoproteins, apoB100 and apoE, in glucose-treated cells and livers of ZDF rats, leading to decreased secretion of VLDL and improvement of hypertriglyceridemia. This study unveils a novel molecular mechanism whereby LA lowers TG via activation of hepatic CREBH and increased expression of Insig-1 and Insig-2a to inhibit de novo lipogenesis and VLDL secretion. These findings provide novel insight into the therapeutic potential of LA as an anti-hypertriglyceridemia dietary molecule.
Asunto(s)
Proteína de Unión a Elemento de Respuesta al AMP Cíclico/agonistas , Suplementos Dietéticos , Hepatocitos/enzimología , Hipertrigliceridemia/dietoterapia , Hipolipemiantes/uso terapéutico , Péptidos y Proteínas de Señalización Intracelular/agonistas , Proteínas de la Membrana/agonistas , Ácido Tióctico/uso terapéutico , Empalme Alternativo , Animales , Línea Celular Tumoral , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Hepatocitos/metabolismo , Hipertrigliceridemia/sangre , Hipertrigliceridemia/metabolismo , Hipolipemiantes/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Lipoproteínas VLDL/sangre , Lipoproteínas VLDL/metabolismo , Masculino , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Procesamiento Proteico-Postraduccional , Distribución Aleatoria , Ratas Endogámicas BUF , Ratas Zucker , Transducción de Señal , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/antagonistas & inhibidores , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Ácido Tióctico/metabolismo , Regulación hacia ArribaRESUMEN
The transcriptional coactivator with a PDZ-binding motif (TAZ) cooperates with various transcriptional factors and plays various roles. Immortalized human mammalian epithelial MCF10A cells form spheres when TAZ is overexpressed and activated. We developed a cell-based assay using sphere formation by TAZ-expressing MCF10A cells as a readout to screen 18,458 chemical compounds for TAZ activators. Fifty compounds were obtained, and 47 were confirmed to activate the TAZ-dependent TEAD-responsive reporter activity in HEK293 cells. We used the derived subset of compounds as a TAZ activator candidate minilibrary and searched for compounds that promote myogenesis in mouse C2C12 myoblast cells. In this study, we focused on one compound, IBS008738. IBS008738 stabilizes TAZ, increases the unphosphorylated TAZ level, enhances the association of MyoD with the myogenin promoter, upregulates MyoD-dependent gene transcription, and competes with myostatin in C2C12 cells. TAZ knockdown verifies that the effect of IBS008738 depends on endogenous TAZ in C2C12 cells. IBS008738 facilitates muscle repair in cardiotoxin-induced muscle injury and prevents dexamethasone-induced muscle atrophy. Thus, this cell-based assay is useful to identify TAZ activators with a variety of cellular outputs. Our findings also support the idea that TAZ is a potential therapeutic target for muscle atrophy.
Asunto(s)
Imidazoles/farmacología , Péptidos y Proteínas de Señalización Intracelular/agonistas , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Desarrollo de Músculos/efectos de los fármacos , Músculos/efectos de los fármacos , Músculos/lesiones , Atrofia Muscular/prevención & control , Animales , Línea Celular , Evaluación Preclínica de Medicamentos/métodos , Femenino , Células HEK293 , Humanos , Imidazoles/uso terapéutico , Péptidos y Proteínas de Señalización Intracelular/genética , Ratones , Ratones Endogámicos BALB C , Músculos/patología , Atrofia Muscular/inducido químicamente , Atrofia Muscular/patología , Proteína MioD/metabolismo , Mioblastos/efectos de los fármacos , Miogenina/genética , Regiones Promotoras Genéticas/efectos de los fármacos , Transactivadores , Factores de Transcripción , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ , Regulación hacia Arriba/efectos de los fármacosAsunto(s)
Hipotálamo/fisiología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Neuropéptidos/metabolismo , Trastornos del Sueño-Vigilia/terapia , Metabolismo Energético , Homeostasis , Humanos , Péptidos y Proteínas de Señalización Intracelular/agonistas , Péptidos y Proteínas de Señalización Intracelular/uso terapéutico , Neuropéptidos/agonistas , Neuropéptidos/uso terapéutico , Orexinas , Receptores Acoplados a Proteínas G/metabolismo , Sueño , Trastornos del Sueño-Vigilia/fisiopatología , VigiliaRESUMEN
Despite significant improvements in the treatment and outcomes of patients with squamous cell carcinoma of the head and neck (SCCHN) that have resulted from technological advances in radiation delivery and the use of cytotoxic chemotherapy, there is still a pressing need for novel therapies. In the last two decades, our understanding of the molecular biological basis of cancer has provided us with a new framework for developing specific targeted therapies. It is likely that the next wave of developments will include active small molecule inhibitors of epidermal growth factor receptor (EGFR) (and other members of the c-erbB family of receptors), antiangiogenic agents, and drugs that can increase proapoptotic signaling in cancer cells. As with cetuximab, it is most likely that these new agents will first find a niche in the context of combination regimens with standard anticancer therapeutics.
Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Terapia Biológica , Carcinoma de Células Escamosas/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales Humanizados , Apoptosis/efectos de los fármacos , Terapia Biológica/tendencias , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Cetuximab , Quimioterapia Adyuvante , Descubrimiento de Drogas , Receptores ErbB/antagonistas & inhibidores , Neoplasias de Cabeza y Cuello/metabolismo , Neoplasias de Cabeza y Cuello/patología , Humanos , Péptidos y Proteínas de Señalización Intracelular/agonistasRESUMEN
Kososan, a Kampo (Japanese herbal) medicine, has an antidepressive-like effect in behavioral animal models of depression and has been used clinically for the improvement of depressive mood. However, mechanism(s) underlying the antidepressive-like effect of kososan remain unknown. Previous studies showed that orexin-A (OX-A), a neuropeptide that is involved in feeding and arousal, exhibits an antidepressive-like property via hippocampal cell proliferation. Here, we used immunohistochemical analysis with bromodeoxyuridine (BrdU), a marker of proliferating cells, to investigate the effect of long-term treatment with kososan on the orexinergic system and on hippocampal cell proliferation. Oral administration of kososan (1.0 g/kg) or milnacipran (60 mg/kg), a serotonin and noradrenaline reuptake inhibitor, for 28 d led to an antidepressive-like effect in the stress-induced depression-like model mice and reversed the stress-induced decrease in the number of OX-A-positive cells in the lateral hypothalamic area. In addition, both kososan and milnacipran alleviated the stress-induced decrease in the number of BrdU-positive cells in the hippocampal dentate gyrus. Moreover, the antidepressive-like effect and the increase in cell proliferation and in the number of neuropeptide Y (NPY, which is closely associated with orexinergic system)-positive cells in the dentate gyrus induced by kososan were blocked by treatment with SB-334867, an orexin receptor 1 antagonist. These results suggest that kososan exerts an antidepressive-like effect via the improvement of the stress-induced decrease in hippocampal cell proliferation and that the mechanism underlying the antidepressive-like effect of kososan, but not of milnacipran, may be associated with the regulation of orexinergic and/or NPYergic transmission.