RESUMEN
Five novel analogs of 6-(ethyl)(4-isobutoxy-3-isopropylphenyl)amino)nicotinic acid-or NEt-4IB-in addition to seven novel analogs of 4-[1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (bexarotene) were prepared and evaluated for selective retinoid-X-receptor (RXR) agonism alongside bexarotene (1), a FDA-approved drug for cutaneous T-cell lymphoma (CTCL). Bexarotene treatment elicits side-effects by provoking or disrupting other RXR-dependent pathways. Analogs were assessed by the modeling of binding to RXR and then evaluated in a human cell-based RXR-RXR mammalian-2-hybrid (M2H) system as well as a RXRE-controlled transcriptional system. The analogs were also tested in KMT2A-MLLT3 leukemia cells and the EC50 and IC50 values were determined for these compounds. Moreover, the analogs were assessed for activation of LXR in an LXRE system as drivers of ApoE expression and subsequent use as potential therapeutics in neurodegenerative disorders, and the results revealed that these compounds exerted a range of differential LXR-RXR activation and selectivity. Furthermore, several of the novel analogs in this study exhibited reduced RARE cross-signaling, implying RXR selectivity. These results demonstrate that modification of partial agonists such as NEt-4IB and potent rexinoids such as bexarotene can lead to compounds with improved RXR selectivity, decreased cross-signaling of other RXR-dependent nuclear receptors, increased LXRE-heterodimer selectivity, and enhanced anti-proliferative potential in leukemia cell lines compared to therapeutics such as 1.
Asunto(s)
Antineoplásicos/farmacología , Apolipoproteínas E/genética , Bexaroteno/farmacología , Leucocitos/efectos de los fármacos , Ácidos Nicotínicos/farmacología , Receptor alfa X Retinoide/agonistas , Animales , Antineoplásicos/síntesis química , Apolipoproteínas E/metabolismo , Bexaroteno/análogos & derivados , Bexaroteno/síntesis química , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Expresión Génica , Humanos , Leucocitos/metabolismo , Leucocitos/patología , Ácidos Nicotínicos/síntesis química , Receptor alfa X Retinoide/genética , Receptor alfa X Retinoide/metabolismo , Relación Estructura-ActividadRESUMEN
We reported recently that berberine (Ber), a traditional oriental medicine to treat gastroenteritis, binds and activates retinoid X receptor α (RXRα) for suppressing the growth of colon cancer cells. Here, we extended our studies based on the binding mode of Ber with RXRα by design, synthesis, and biological evaluation of a focused library of 15 novel Ber analogues. Among them, 3,9-dimethoxy-5,6-dihydroisoquinolino[3,2-a]isoquinolin-7-ium chloride (B-12) was identified as the optimal RXRα activator. More efficiently than Ber, B-12 bound and altered the conformation of RXRα/LBD, thereby suppressing the Wnt/ß-catenin pathway and colon cancer cell growth via RXRα mediation. In addition, B-12 not only preserved Ber's tumor selectivity but also greatly improved its bioavailability. Remarkably, in mice, B-12 did not show obvious side effects including hypertriglyceridemia as other RXRα agonists or induce hepatorenal toxicity. Together, our study describes an approach for the rational design of Ber-derived RXRα activators as novel effective antineoplastic agents for colon cancer.
Asunto(s)
Antineoplásicos/química , Berberina/análogos & derivados , Receptor alfa X Retinoide/agonistas , Animales , Antineoplásicos/metabolismo , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Berberina/metabolismo , Sitios de Unión , Línea Celular Tumoral , Proliferación Celular , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/metabolismo , Neoplasias del Colon/patología , Evaluación Preclínica de Medicamentos , Semivida , Humanos , Masculino , Ratones , Ratones Desnudos , Simulación del Acoplamiento Molecular , Estructura Terciaria de Proteína , Ratas , Receptor alfa X Retinoide/metabolismo , Transducción de Señal/efectos de los fármacos , Relación Estructura-Actividad , Trasplante HeterólogoRESUMEN
To uncover the genetic basis of anthracycline-induced cardiotoxicity (AIC), we recently established a genetic suppressor screening strategy in zebrafish. Here, we report the molecular and cellular nature of GBT0419, a salutary modifier mutant that affects retinoid x receptor alpha a (rxraa). We showed that endothelial, but not myocardial or epicardial, RXRA activation confers AIC protection. We then identified isotretinoin and bexarotene, two FDA-approved RXRA agonists, which exert cardioprotective effects. The therapeutic effects of these drugs only occur when administered during early, but not late, phase of AIC or as pretreatment. Mechanistically, these spatially- and temporally-predominant benefits of RXRA activation can be ascribed to repair of damaged endothelial cell-barrier via regulating tight-junction protein Zonula occludens-1. Together, our study provides the first in vivo genetic evidence supporting RXRA as the therapeutic target for AIC, and uncovers a previously unrecognized spatiotemporally-predominant mechanism that shall inform future translational efforts.
Asunto(s)
Cardiotoxicidad/tratamiento farmacológico , Corazón/efectos de los fármacos , Receptor alfa X Retinoide/genética , Proteína de la Zonula Occludens-1/genética , Animales , Bexaroteno/farmacología , Cardiotónicos/farmacología , Cardiotoxicidad/etiología , Cardiotoxicidad/genética , Modelos Animales de Enfermedad , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Corazón/fisiopatología , Humanos , Isotretinoína/farmacología , Miocardio/metabolismo , Miocardio/patología , Neoplasias/complicaciones , Neoplasias/tratamiento farmacológico , Pericardio/efectos de los fármacos , Receptor alfa X Retinoide/agonistas , Pez CebraRESUMEN
Renal cell carcinoma (RCC) is the most common malignant kidney tumors in adults. Von Hippel-Lindau (VHL) gene is deficient in >50% of RCC cases, but the role of VHL as a potential therapeutic target in RCC has not been well established. In the present study, 9-cis-Retinoic acid, which is a potent natural agonist of retinoid X receptors (RXRs), was found to decrease the viability of VHL-proficient RCC cells, but had little effect on VHL-deficient RCC cells. In addition, it was demonstrated that VHL transcriptionally regulated RXRα in a hypoxia-inducible factor-α independent manner. Moreover, a negative correlation was observed between the expressions of VHL and RXRα in RCC tissues. Collectively, these data indicate that VHL-proficient RCC patients may be more sensitive to treatment with 9-cis-retinoic acid, which acts by regulating RXRα expression, compared with VHL-deficient RCC patients. The findings of the present study demonstrate a novel function of VHL and highlight the potential of VHL expression as a therapeutic modality for the optimized treatment of RCC patients.
Asunto(s)
Alitretinoína/farmacología , Carcinoma de Células Renales/tratamiento farmacológico , Neoplasias Renales/tratamiento farmacológico , Receptor alfa X Retinoide/metabolismo , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/metabolismo , Antineoplásicos/farmacología , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Receptor alfa X Retinoide/agonistas , Receptor alfa X Retinoide/genética , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/genéticaRESUMEN
Radiation therapy is a common treatment for prostate cancer, however recurrence remains a problem. MicroRNA expression is altered in prostate cancer and may promote therapy resistance. Through bioinformatic analyses of TCGA and CPC-GENE patient cohorts, we identified higher miR-191 expression in tumor versus normal tissue, and increased expression in higher Gleason scores. In vitro and in vivo experiments demonstrated that miR-191 overexpression promotes radiation survival, and contributes to a more aggressive phenotype. Retinoid X receptor alpha, RXRA, was discovered to be a novel target of miR-191, and knockdown recapitulated radioresistance. Furthermore, treatment of prostate cancer cells with the RXRA agonist 9-cis-retinoic acid restored radiosensitivity. Supporting this relationship, patients with high miR-191 and low RXRA abundance experienced quicker biochemical recurrence. Reduced RXRA translated to a higher risk of distant failure after radiotherapy. Notably, this miR-191/RXRA interaction was conserved in a novel primary cell line derived from radiorecurrent prostate cancer. Together, our findings demonstrate that miR-191 promotes prostate cancer survival after radiotherapy, and highlights retinoids as a potential option to improve radiotherapy response.
Asunto(s)
Biomarcadores de Tumor/metabolismo , MicroARNs/metabolismo , Recurrencia Local de Neoplasia/genética , Neoplasias de la Próstata/terapia , Tolerancia a Radiación/genética , Receptor alfa X Retinoide/genética , Alitretinoína/administración & dosificación , Animales , Antineoplásicos/administración & dosificación , Línea Celular Tumoral , Quimioradioterapia Adyuvante/métodos , Supervivencia sin Enfermedad , Regulación hacia Abajo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Humanos , Calicreínas/sangre , Estimación de Kaplan-Meier , Masculino , Ratones , MicroARNs/agonistas , Persona de Mediana Edad , Clasificación del Tumor , Recurrencia Local de Neoplasia/sangre , Recurrencia Local de Neoplasia/patología , Recurrencia Local de Neoplasia/prevención & control , Cultivo Primario de Células , Pronóstico , Próstata/patología , Próstata/cirugía , Antígeno Prostático Específico/sangre , Prostatectomía , Neoplasias de la Próstata/sangre , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Tolerancia a Radiación/efectos de los fármacos , Receptor alfa X Retinoide/agonistas , Tasa de Supervivencia , Factores de Tiempo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
This chapter outlines the materials, methods, and procedures for the in vitro biological evaluation of retinoid-X-receptor (RXR) agonists including 6-(ethyl(5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalen-2-yl)amino)nicotinic acid (NEt-TMN), as well as several NEt-TMN analog compounds recently reported by our group. These methods have general applicability beyond this NEt-TMN case study, and can be employed to characterize and biologically evaluate other putative RXR agonists (rexinoids), and benchmarked against perhaps the most common rexinoid known as bexarotene (Bex), a drug awarded FDA approval for the treatment of cutaneous T-cell lymphoma in 1999 but that is also prescribed for non-small cell lung cancer and continues to be explored in multiple human cancer types. The side-effect profile of Bex treatment includes hypothyroidism and hypertriglyceridemia arising from the inhibition or activation of additional nuclear receptors that partner with RXR. Because rexinoids often exhibit selectivity for RXR activation, versus activating the retinoic-acid-receptor (RAR), rexinoid treatment avoids the cutaneous toxicity commonly associated as a side effect with retinoids. There are many examples of other potent rexinoids, where biological evaluation has contributed useful insight into qSAR studies on these compounds, often also benchmarked to Bex, as potential treatments for cancer. Because of differential pleiotropy in other pathways, even closely related rexinoids display unique side-effect and activity profiles. Notable examples of potent rexinoids in addition to Bex and NEt-TMN include CD3254, LGD100268, and 9-cis-UAB30. Indeed, the methods described herein to evaluate NEt-TMN and analogous rexinoids are generally applicable to a wider variety of potent, moderate, and even weak RXR ligands.In terms of in vitro biological evaluation, methods for a rapid and preliminary assessment of rexinoid activity are described by employing a biologically relevant, RXR-responsive element (RXRE)-mediated transcription assay in mammalian cells. In addition, a second, more sensitive assay is also detailed that utilizes activation of RXR-RXR homodimers in the context of a mammalian two-hybrid (M2H) luciferase assay. Methods for applying the M2H assay at different rexinoid concentrations are further described for the determination of EC50 values for rexinoids from dose-response curves.
Asunto(s)
Receptor alfa X Retinoide/agonistas , Tetrahidronaftalenos/farmacología , Ácidos Cumáricos/farmacología , Evaluación Preclínica de Medicamentos , Regulación de la Expresión Génica , Células HEK293 , Humanos , Retinoides/farmacología , Transducción de SeñalRESUMEN
The protocols in this chapter describe methods for identifying the functional roles of retinoic acid receptor (RAR) and retinoid X receptor (RXR) signaling in atherosclerosis and developing RARα/RXRα-specific agonists as hemodynamics-based therapeutic components for atherosclerosis treatment. In vitro cell culture flow system is used to elucidate the effects of different flow patterns and shear stresses, i.e., atherogenic oscillatory shear stress (OS) vs. atheroprotective pulsatile shear stress (PS), on RAR/RXR signaling and inflammatory responses in vascular endothelial cells (ECs). Western blotting, nuclear and cytoplasmic protein extraction, immunoprecipitation, and in situ proximity ligation assay are used to examine the expression, location, and association of RARs (i.e., RARα, RARß, and RARγ) and RXRs (i.e., RXRα, RXRß, and RXRγ) in ECs in response to OS vs. PS. Chromatin immunoprecipitation is used to examine the binding activity of RARα/RA-responsive elements (RARE). RT-microRNA (miR) quantitative real-time PCR and RT-PCR are used to detect the expressions of miR-10a and pro-inflammatory molecules, respectively. Specific siRNAs of RARα and RXRα, precursor miR-10a (PreR-10a), and antagomiR-10a (AMR-10a) are used to elucidate the regulatory roles of RARα, RXRα, and miR-10a in pro-inflammatory signaling in ECs. RARα/RXRα-specific agonists are used to induce miR-10a expression and inhibit OS-induced pro-inflammatory signaling in ECs in vitro. Apolipoprotein E-deficient (ApoE-/-) mice are used as an atherosclerotic animal model. Administration of ApoE-/- mice with RARα/RXRα-specific agonists results in inhibitions in atherosclerotic lesion formation. Co-administration of ApoE-/- mice with RARα/RXRα agonists and AMR-10a is performed to identify the role of miR-10a in RARα/RXRα agonists-mediated inhibition in atherosclerotic lesions. Oil Red O staining and H&E staining are used to examine the levels of atherosclerotic lesions in the vessel wall. In situ miR hybridization and immunohistochemical staining are used to detect the expression of miR-10a and pro-inflammatory molecules and the infiltration of inflammatory cells in the vessel wall. RARα/RXRα-specific agonists are used to mimic the atheroprotective effects of PS to induce endothelial miR-10a and hence repress OS-induced pro-inflammatory signaling and atherosclerotic lesion formation in vivo. The results indicate that RAR/RXR-specific agonists have great potential to be developed as hemodynamics-based therapeutic components for atherosclerosis treatment.
Asunto(s)
Antagomirs/administración & dosificación , Aterosclerosis/tratamiento farmacológico , Benzoatos/administración & dosificación , Ácidos Cumáricos/administración & dosificación , MicroARNs/genética , Tetrahidronaftalenos/administración & dosificación , Animales , Antagomirs/farmacología , Aterosclerosis/genética , Aterosclerosis/metabolismo , Benzoatos/farmacología , Línea Celular , Ácidos Cumáricos/farmacología , Citocinas/genética , Citocinas/metabolismo , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/efectos de los fármacos , Hemodinámica , Humanos , Ratones , MicroARNs/antagonistas & inhibidores , Receptor alfa de Ácido Retinoico/agonistas , Receptor alfa X Retinoide/agonistas , Transducción de Señal/efectos de los fármacos , Tetrahidronaftalenos/farmacologíaRESUMEN
BACKGROUND AND AIMS: MicroRNA (miR)-10a is a shear-regulated miR with the lowest expression in vascular endothelial cells (ECs) in athero-susceptible regions with oscillatory shear stress (OS). The aim of this study is to elucidate the relationship between EC miR-10a and atherosclerosis and develop a hemodynamics-based strategy for atherosclerosis treatment. METHODS: A combination of in vitro flow system and in vivo experimental animals was used to examine the functional roles of EC miR-10a and its clinical applications in atherosclerosis. RESULTS: En face staining showed that EC miR-10a is down-regulated in the inner curvature (OS region) of aortic arch in rats. Co-administration with retinoic acid receptor-α (RARα)- and retinoid X receptor-α (RXRα)-specific agonists rescued EC miR-10a expression in this OS region. These effects of OS and RARα/RXRα-specific agonists on EC miR-10a expression were confirmed by the in vitro flow system, and were modulated by the RARα-histone deacetylases complex, with the consequent modulation in the downstream GATA6/vascular cell adhesion molecule (VCAM)-1 signaling cascade. Animal studies showed that miR-10a levels are decreased in both aortic endothelium of atherosclerotic lesions and blood plasma from apolipoprotein E-deficient (ApoE-/-) mice. In vivo induction of EC miR-10a by administration of RARα/RXRα-specific agonists protects ApoE-/- mice from atherosclerosis through inhibition of GATA6/VCAM-1 signaling and inflammatory cell infiltration. CONCLUSIONS: Our findings indicate that down-regulation of miR-10a in aortic endothelium and blood serum is associated with atherosclerosis, and miR-10a has potential to be developed as diagnostic molecule for atherosclerosis. Moreover, EC miR-10a induction by RARα/RXRα-specific agonists is a potential hemodynamics-based strategy for atherosclerosis treatment.
Asunto(s)
Aorta/efectos de los fármacos , Enfermedades de la Aorta/prevención & control , Aterosclerosis/prevención & control , Benzoatos/farmacología , Ácidos Cumáricos/farmacología , MicroARNs/metabolismo , Placa Aterosclerótica , Receptor alfa de Ácido Retinoico/agonistas , Receptor alfa X Retinoide/agonistas , Tetrahidronaftalenos/farmacología , Animales , Aorta/metabolismo , Aorta/patología , Aorta/fisiopatología , Enfermedades de la Aorta/genética , Enfermedades de la Aorta/metabolismo , Enfermedades de la Aorta/patología , Aterosclerosis/genética , Aterosclerosis/metabolismo , Aterosclerosis/patología , Células Cultivadas , Modelos Animales de Enfermedad , Factor de Transcripción GATA6/metabolismo , Hemodinámica , Humanos , Mecanotransducción Celular/efectos de los fármacos , Ratones Noqueados para ApoE , MicroARNs/genética , Ratas , Flujo Sanguíneo Regional , Receptor alfa de Ácido Retinoico/metabolismo , Receptor alfa X Retinoide/metabolismo , Estrés Mecánico , Regulación hacia Arriba , Molécula 1 de Adhesión Celular Vascular/metabolismoRESUMEN
Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that can activate or inhibit the expression of many target genes by forming a heterodimer complex with the retinoid X receptor (RXR). The aim of this study was to investigate effects of bexarotene, a selective RXRα agonist, on the changes in renal, cardiac, hepatic, and pulmonary expression/activity of inducible nitric oxide synthase (iNOS) and cytochrome P450 (CYP) 4F6 in relation to PPARα/ß/γ-RXRα heterodimer formation in a rat model of septic shock. Rats were injected with dimethyl sulfoxide or bexarotene 1 h after administration of saline or lipopolysaccharide (LPS). Mean arterial pressure (MAP) and heart rate (HR) were recorded from rats, which had received either saline or LPS before and after 1, 2, 3, and 4 h. Serum iNOS, LTB4, myeloperoxidase (MPO), and lactate dehydrogenase (LDH) levels as well as tissue iNOS and CYP4F6 mRNA expression in addition to PPARα/ß/γ and RXRα proteins were measured. LPS-induced decrease in MAP and increase in HR were associated with a decrease in PPARα/ß/γ-RXRα heterodimer formation and CYP4F6 mRNA expression. LPS also caused an increase in systemic iNOS, LTB4, MPO, and LDH levels as well as iNOS mRNA expression. Bexarotene at 0.1 mg/kg (i.p.) prevented the LPS-induced changes, except tachycardia. The results suggest that increased formation of PPARα/ß/γ-RXRα heterodimers and CYP4F6 expression/activity in addition to decreased iNOS expression contributes to the beneficial effect of bexarotene to prevent the hypotension associated with inflammation and tissue injury during rat endotoxemia.
Asunto(s)
Presión Arterial/efectos de los fármacos , Hipotensión/prevención & control , Inflamación/tratamiento farmacológico , Receptor alfa X Retinoide/agonistas , Choque Séptico/tratamiento farmacológico , Tetrahidronaftalenos/farmacología , Animales , Bexaroteno , Familia 4 del Citocromo P450/genética , Familia 4 del Citocromo P450/metabolismo , Modelos Animales de Enfermedad , Frecuencia Cardíaca/efectos de los fármacos , Hipotensión/inducido químicamente , Hipotensión/metabolismo , Hipotensión/fisiopatología , Inflamación/inducido químicamente , Inflamación/metabolismo , Inflamación/fisiopatología , Riñón/efectos de los fármacos , Riñón/metabolismo , L-Lactato Deshidrogenasa/sangre , Leucotrieno B4/sangre , Lipopolisacáridos , Hígado/efectos de los fármacos , Hígado/metabolismo , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Masculino , Complejos Multiproteicos , Miocardio/metabolismo , Óxido Nítrico Sintasa de Tipo II/genética , Óxido Nítrico Sintasa de Tipo II/metabolismo , Peroxidasa/sangre , Receptores Activados del Proliferador del Peroxisoma/metabolismo , Ratas Wistar , Receptor alfa X Retinoide/metabolismo , Choque Séptico/inducido químicamente , Choque Séptico/metabolismo , Choque Séptico/fisiopatología , Transducción de Señal/efectos de los fármacosRESUMEN
Retinoid X receptors (RXRs) play key roles in many physiological processes in both the periphery and central nervous system. In addition, RXRs form heterodimers with other nuclear receptors to exert their physiological effects. The nuclear receptor related 1 protein (NURR1) is particularly interesting because of its role in promoting differentiation and survival of dopamine neurons. However, only a small number of RXR-heterodimer selective modulators are available, with limited chemical diversity. This work describes the synthesis, biochemical evaluation, and structural elucidation of a novel series of RXR ligands with strongly biased interactions with RXRα-NURR1 heterodimers. Targeted modifications to the small molecule biaryl scaffold caused local RXRα side-chain disturbances and displacement of secondary structural elements upon ligand binding. This resulted in the repositioning of protein helices in the heterodimer interface of RXRα, alterations in homo- versus heterodimer formation, and modulation of activation function 2 (AF2). The data provide a rationale for the design of RXR ligands consisting of a highly conserved hydrophilic region, strongly contributing to the ligand affinity, and a variable hydrophobic region, which efficiently probes the effects of structural changes at the level of the ligand on co-regulator recruitment or the RXRα-NURR1 dimerization interface.
Asunto(s)
Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/química , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Receptor alfa X Retinoide/química , Receptor alfa X Retinoide/metabolismo , Diseño de Fármacos , Escherichia coli , Ésteres/química , Éteres/química , Humanos , Enlace de Hidrógeno , Ligandos , Modelos Moleculares , Estructura Molecular , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/agonistas , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/antagonistas & inhibidores , Unión Proteica , Multimerización de Proteína , Receptor alfa X Retinoide/agonistas , Receptor alfa X Retinoide/antagonistas & inhibidores , Técnicas del Sistema de Dos HíbridosRESUMEN
Bexarotene is an FDA approved retinoid X-receptor (RXR) agonist for the treatment of cutaneous T-cell lymphoma, and its use in other cancers and Alzheimer's disease is being investigated. The drug causes serious side effects, which might be reduced by chemical modifications of the molecule. To rationalize known agonists and to help identify sites for potential substitutions we present molecular simulations in which the RXR ligand-binding domain was flooded with a large number of drug-like molecules, and molecular dynamics simulations of a series of bexarotene-like ligands bound to the RXR ligand-binding domain. Based on the flooding simulations, two regions of interest for ligand modifications were identified: a hydrophobic area near the bridgehead and another near the fused ring. In addition, positional fluctuations of the phenyl ring were generally smaller than fluctuations of the fused ring of the ligands. Together, these observations suggest that the fused ring might be a good target for the design of higher affinity bexarotene-like ligands, while the phenyl ring is already optimized. In addition, notable differences in ligand position and interactions between the RXRα and RXRß were observed, as well as differences in hydrogen bonding and solvation, which might be exploited in the development of subspecies-specific ligands.
Asunto(s)
Receptor alfa X Retinoide/química , Receptor beta X Retinoide/química , Tetrahidronaftalenos/química , Bexaroteno , Sitios de Unión , Humanos , Enlace de Hidrógeno , Ligandos , Simulación de Dinámica Molecular , Unión Proteica , Receptor alfa X Retinoide/agonistas , Receptor beta X Retinoide/agonistas , Tetrahidronaftalenos/efectos adversos , Tetrahidronaftalenos/uso terapéuticoRESUMEN
Adrenal gland reportedly expresses many nuclear receptors that are known to heterodimerize with retinoid-X-receptor (RXR) for functions, but the information regarding the glandular RXR is not adequate. Studies of rat adrenal homogenate by Western blotting revealed three RXR proteins: RXRα (55kDa), RXRß (47kDa) and RXR (56kDa). RXRγ was not detectable. After fractionation, RXRα was almost exclusively localized in the nuclear fraction. In comparison, substantial portions of RXRß and RXR were found in both nuclear and post-nuclear particle fractions, suggesting genomic and non-genomic functions. Cells immunostained for RXRα were primarily localized in zona fasciculata (ZF) and medulla, although some stained cells were found in zona glomerulosa (ZG) and zona reticularis (ZR). In contrast, cells immunostained for RXRß were concentrated principally in ZG, although some stained cells were seen in ZR, ZF, and medulla (in descending order, qualitatively). Analysis of adrenal lipid extracts by LC/MS did not detect 9-cis-retinoic acid (a potent RXR-ligand) but identified all-trans retinoic acid. Since C20 and C22 polyunsaturated fatty acids (PUFAs) can also activate RXR, subcellular availabilities of unesterified fatty acids were investigated by GC/MS. As results, arachidonic acid (C20:4), adrenic acid (C22:4), docosapentaenoic acid (C22:5), and cervonic acid (C22:6) were detected in the lipids extracted from each subcellular fraction. Thus, the RXR-agonizing PUFAs are available in all the main subcellular compartments considerably. The present findings not only shed light on the adrenal network of RXRs but also provide baseline information for further investigations of RXR heterodimers in the regulation of adrenal steroidogenesis.
Asunto(s)
Glándulas Suprarrenales/metabolismo , Ácidos Grasos Insaturados/metabolismo , Receptor alfa X Retinoide/metabolismo , Receptor beta X Retinoide/metabolismo , Tretinoina/metabolismo , Corteza Suprarrenal/citología , Corteza Suprarrenal/metabolismo , Glándulas Suprarrenales/citología , Médula Suprarrenal/citología , Médula Suprarrenal/metabolismo , Animales , Biomarcadores/metabolismo , Núcleo Celular/metabolismo , Humanos , Ligandos , Hígado/citología , Hígado/metabolismo , Masculino , Peso Molecular , Especificidad de Órganos , Dominios y Motivos de Interacción de Proteínas , Isoformas de Proteínas/agonistas , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Transporte de Proteínas , Ratas Wistar , Receptor alfa X Retinoide/agonistas , Receptor alfa X Retinoide/química , Receptor alfa X Retinoide/genética , Receptor beta X Retinoide/agonistas , Receptor beta X Retinoide/química , Receptor beta X Retinoide/genética , Zona Fascicular/citología , Zona Fascicular/metabolismo , Zona Reticular/citología , Zona Reticular/metabolismoRESUMEN
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic (DAergic) neurons in the substantia nigra and the gradual depletion of dopamine (DA). Current treatments replenish the DA deficit and improve symptoms but induce dyskinesias over time, and neuroprotective therapies are nonexistent. Here we report that Nuclear receptor-related 1 (Nurr1):Retinoid X receptor α (RXRα) activation has a double therapeutic potential for PD, offering both neuroprotective and symptomatic improvement. We designed BRF110, a unique in vivo active Nurr1:RXRα-selective lead molecule, which prevents DAergic neuron demise and striatal DAergic denervation in vivo against PD-causing toxins in a Nurr1-dependent manner. BRF110 also protects against PD-related genetic mutations in patient induced pluripotent stem cell (iPSC)-derived DAergic neurons and a genetic mouse PD model. Remarkably, besides neuroprotection, BRF110 up-regulates tyrosine hydroxylase (TH), aromatic l-amino acid decarboxylase (AADC), and GTP cyclohydrolase I (GCH1) transcription; increases striatal DA in vivo; and has symptomatic efficacy in two postneurodegeneration PD models, without inducing dyskinesias on chronic daily treatment. The combined neuroprotective and symptomatic effects of BRF110 identify Nurr1:RXRα activation as a potential monotherapeutic approach for PD.
Asunto(s)
Antiparkinsonianos/farmacología , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Enfermedad de Parkinson/tratamiento farmacológico , Receptor alfa X Retinoide/metabolismo , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina , Animales , Antiparkinsonianos/química , Antiparkinsonianos/farmacocinética , Encéfalo/efectos de los fármacos , Línea Celular , Modelos Animales de Enfermedad , Dopamina/genética , Estabilidad de Medicamentos , Humanos , Masculino , Ratones Endogámicos BALB C , Terapia Molecular Dirigida , Neuronas/efectos de los fármacos , Neuronas/patología , Neuronas/fisiología , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/agonistas , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/genética , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/patología , Multimerización de Proteína , Ratas , Receptor alfa X Retinoide/agonistas , Receptor alfa X Retinoide/química , Receptor alfa X Retinoide/genéticaRESUMEN
Parkinson's disease (PD) is a serious neurodegenerative disorder that lacks effective therapeutic methods. In this research, expressions of PPARα, RXRα, and miR-21 were evaluated in PD patients and normal controls. To investigate the effects of miR-21, docosahexaenoic acid (DHA) and aspirin (ASA) on PD, as well as the relationships between them, SH-Y5Y cells were treated with DHA, ASA, or both for 24 h. The assay showed that levels of miR-21 were increased and levels of PPARα were decreased in PD patients compared with normal controls. miR-21 was negatively correlated with PPARα in PD patients. DHA and ASA could activate RXRα and PPARα, respectively. Additionally, DHA upregulated PPARα expression by inhibiting miR-21 in SH-Y5Y cells. A combination of DHA and ASA efficiently enhanced heterodimer formations of PPARα and RXRα and increased the expression of neurotrophic factors PSD-95, brain-derived neurotrophic factor (BDNF), and glial cell-derived neurotrophic factor (GDNF), while inhibiting NFκB and COX2. These findings suggest that a combination of DHA and ASA could significantly improve the expression of PSD-95, BDNF, and GDNF by promoting heterodimerization of PPARα and RXRα, thus supplying a new therapeutic method for PD.
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Aspirina/farmacología , Ácidos Docosahexaenoicos/farmacología , MicroARNs/antagonistas & inhibidores , Fármacos Neuroprotectores/farmacología , PPAR alfa/metabolismo , Receptor alfa X Retinoide/metabolismo , Secuencia de Bases , Línea Celular Tumoral , Sinergismo Farmacológico , Humanos , PPAR alfa/agonistas , PPAR alfa/genética , Receptor alfa X Retinoide/agonistas , Transducción de Señal/efectos de los fármacosRESUMEN
Matched molecular pair analysis was used to evaluate the ability of a tetrazolone group to act as a bioisostere of a carboxylic acid. Compound 7, a tetrazolone of the anti-hypertensive drug, telmisartan 6, was shown to be a potent AT1 antagonist (Kb = 0.14 nM), with activity comparable to telmisartan itself (Kb = 0.44 nM). Additionally, compound 9, a tetrazolone congener of the marketed anti-cancer agent, bexarotene 8, was shown to be an agonist at the retinoid X receptor alpha (EC50 = 64 nM). Compounds containing a tetrazolone group showed similar microsomal stability and plasma protein binding to marketed acid counterparts, while also reducing the value for clog P. Furthermore, compound 7 displayed an improved rat pharmacokinetic profile cf. telmisartan 6. Taken together, the results demonstrate that a tetrazolone group may serve as a bioisostere for a carboxylic acid.
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Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Bencimidazoles/química , Benzoatos/química , Tetrahidronaftalenos/química , Tetrazoles/química , Bloqueadores del Receptor Tipo 1 de Angiotensina II/química , Animales , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/farmacología , Bencimidazoles/farmacocinética , Bencimidazoles/farmacología , Benzoatos/farmacocinética , Benzoatos/farmacología , Bexaroteno , Proteínas Sanguíneas/metabolismo , Ácidos Carboxílicos/química , Ciclooxigenasa 1/metabolismo , Inhibidores de la Ciclooxigenasa/química , Inhibidores de la Ciclooxigenasa/farmacología , Evaluación Preclínica de Medicamentos/métodos , Semivida , Humanos , Microsomas Hepáticos/efectos de los fármacos , Ratas , Receptor alfa X Retinoide/agonistas , Telmisartán , Tetrahidronaftalenos/farmacologíaRESUMEN
Expression of ATP-binding cassette transporter G1 (ABCG1), a molecule facilitating cholesterol efflux to HDL, is activated by liver X receptor (LXR). In this study, we investigated if inhibition of ERK1/2 can activate macrophage ABCG1 expression and functions. MEK1/2 inhibitors, PD98059 and U0126, increased ABCG1 mRNA and protein expression, and activated the natural ABCG1 promoter but not the promoter with the LXR responsive element (LXRE) deletion. Inhibition of ABCG1 expression by ABCG1 siRNA did enhance the formation of macrophage/foam cells and it attenuated the inhibitory effect of MEK1/2 inhibitors on foam cell formation. MEK1/2 inhibitors activated macrophage cholesterol efflux to HDL in vitro, and they enhanced reverse cholesterol transport (RCT) in vivo. ApoE deficient (apoE(-/-)) mice receiving U0126 treatment had reduced sinus lesions in the aortic root which was associated with activated macrophage ABCG1 expression in the lesion areas. MEK1/2 inhibitors coordinated the RXR agonist, but not the LXR agonist, to induce ABCG1 expression. Furthermore, induction of ABCG1 expression by MEK1/2 inhibitors was associated with activation of SIRT1, a positive regulator of LXR activity, and inactivation of SULT2B1 and RIP140, two negative regulators of LXR activity. Taken together, our study suggests that MEK1/2 inhibitors activate macrophage ABCG1 expression/RCT, and inhibit foam cell formation and lesion development by multiple mechanisms, supporting the concept that ERK1/2 inhibition is anti-atherogenic.
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Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 1/biosíntesis , Aterosclerosis/genética , Transporte Biológico/genética , Colesterol/metabolismo , Receptores X del Hígado/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 1/genética , Animales , Aorta/metabolismo , Apolipoproteínas E/genética , Aterosclerosis/tratamiento farmacológico , Aterosclerosis/metabolismo , Transporte Biológico/efectos de los fármacos , Butadienos/administración & dosificación , Colesterol/genética , Flavonoides/administración & dosificación , Células Espumosas/efectos de los fármacos , Células Espumosas/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Receptores X del Hígado/biosíntesis , MAP Quinasa Quinasa 1/antagonistas & inhibidores , MAP Quinasa Quinasa 1/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Ratones Noqueados , Nitrilos/administración & dosificación , Regiones Promotoras Genéticas , Receptor alfa X Retinoide/agonistas , Receptor alfa X Retinoide/genética , Sirtuina 1/biosíntesisRESUMEN
Repurposing of existing cancer drugs to overcome their physical limitations, such as insolubility, represents an attractive strategy to achieve enhanced therapeutic efficacy and broaden the range of clinical applications. Such an approach also promises to offer substantial cost savings in drug development efforts. Here we repurposed FDA-approved topical agent bexarotene (Targretin), currently in limited use for cutaneous manifestations of T-cell lymphomas, and re-engineer it for use in solid tumor applications by forming self-assembling nanobubbles. Physico-chemical characterization studies of the novel prodrug nanobubbles demonstrated their stability, enhanced target cell internalization capability, and highly controlled release profile in response to application of focused ultrasound energy. Using an in vitro model of hepatocellular carcinoma and an in vivo large animal model of liver ablation, we demonstrate the effectiveness of bexarotene prodrug nanobubbles when used in conjunction with catheter-based ultrasound, thereby highlighting the therapeutic promise of this trimodal approach.
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Reposicionamiento de Medicamentos , Hipertermia Inducida , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/terapia , Tetrahidronaftalenos/uso terapéutico , Ultrasonido , Animales , Bexaroteno , Catéteres , Terapia Combinada , Modelos Animales de Enfermedad , Electricidad , Electroforesis , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Células Hep G2 , Humanos , Concentración de Iones de Hidrógeno , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , Simulación de Dinámica Molecular , Nanopartículas/química , Profármacos/síntesis química , Profármacos/uso terapéutico , Teoría Cuántica , Receptor alfa X Retinoide/agonistas , Receptor alfa X Retinoide/metabolismo , Espectrometría Raman , Sus scrofa , Tetrahidronaftalenos/síntesis química , Termodinámica , UltrasonografíaRESUMEN
The efficiency of central nervous system remyelination declines with age. This is in part due to an age-associated decline in the phagocytic removal of myelin debris, which contains inhibitors of oligodendrocyte progenitor cell differentiation. In this study, we show that expression of genes involved in the retinoid X receptor pathway are decreased with ageing in both myelin-phagocytosing human monocytes and mouse macrophages using a combination of in vivo and in vitro approaches. Disruption of retinoid X receptor function in young macrophages, using the antagonist HX531, mimics ageing by reducing myelin debris uptake. Macrophage-specific RXRα (Rxra) knockout mice revealed that loss of function in young mice caused delayed myelin debris uptake and slowed remyelination after experimentally-induced demyelination. Alternatively, retinoid X receptor agonists partially restored myelin debris phagocytosis in aged macrophages. The agonist bexarotene, when used in concentrations achievable in human subjects, caused a reversion of the gene expression profile in multiple sclerosis patient monocytes to a more youthful profile and enhanced myelin debris phagocytosis by patient cells. These results reveal the retinoid X receptor pathway as a positive regulator of myelin debris clearance and a key player in the age-related decline in remyelination that may be targeted by available or newly-developed therapeutics.
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Envejecimiento/metabolismo , Envejecimiento/patología , Vaina de Mielina/metabolismo , Fagocitosis , Receptor alfa X Retinoide/metabolismo , Adulto , Animales , Benzoatos/farmacología , Bexaroteno , Compuestos de Bifenilo/farmacología , Femenino , Humanos , Macrófagos/citología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Masculino , Ratones , Ratones Noqueados , Persona de Mediana Edad , Monocitos/citología , Monocitos/efectos de los fármacos , Monocitos/metabolismo , Esclerosis Múltiple/metabolismo , Fagocitosis/efectos de los fármacos , Receptor alfa X Retinoide/agonistas , Receptor alfa X Retinoide/antagonistas & inhibidores , Receptor alfa X Retinoide/genética , Transducción de Señal/fisiología , Tetrahidronaftalenos/farmacología , Transcriptoma/efectos de los fármacos , Adulto JovenRESUMEN
Alzheimer's disease (AD) is a neurodegenerative disease, which is characterized by progressive cognitive impairments. The ß-amyloid (Aß)-induced neurodegeneration is determined as the main pathogenesis of AD, and either decrease of Aß production or increase of Aß clearance is beneficial in the treatment of AD, while Aß clearance regulation seems to be more attractive as a promising therapeutic strategy against AD based on the fact that the insufficient clearance of Aß is tightly associated with the late onset of AD that is represented as the majority of AD cases. Here, we report that the small molecular compound, methyl 2-amino-6-(tert-butyl)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate (TBTC), as a selective agonist of retinoid X receptor α (RXRα) can effectively activate the heterodimerization of RXRα with either liver X receptor α (LXRα) or peroxisome proliferator activated receptor γ (PPARγ), stimulate the expressions of the genes of apoE, ABCA1 and ABCG1, and decrease Aß content both in cells and animal models. In addition, administration of TBTC (30mg/kg/day) in the transgenic APP-PS1 mice could also reduce the formation of senile plaques and improve the daily living activity of the mice. Therefore, our findings have suggested that TBTC might hold the potential as a drug lead compound for the treatment of AD.
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Enfermedad de Alzheimer/tratamiento farmacológico , Receptor alfa X Retinoide/agonistas , Tiofenos/farmacología , Transportador 1 de Casete de Unión a ATP/genética , Transportador 1 de Casete de Unión a ATP/metabolismo , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 1 , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/fisiopatología , Péptidos beta-Amiloides/metabolismo , Animales , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Cognición/efectos de los fármacos , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/efectos de los fármacos , Células HEK293 , Humanos , Lipoproteínas/genética , Lipoproteínas/metabolismo , Ratones , Ratones Transgénicos , Comportamiento de Nidificación/efectos de los fármacos , Placa Amiloide/tratamiento farmacológico , Tiofenos/uso terapéuticoRESUMEN
Retinoid X receptor alpha (RXRα) and its N-terminally truncated version, tRXRα, are widely implicated in cancer development and represent intriguing targets for cancer prevention and treatment. Successful manipulation of RXRα and tRXRα requires the identification of their modulators that could produce therapeutic effects. Here, we report that a class of nitrostyrene derivatives bind to RXRα by a unique mechanism, of which the nitro group of nitrostyrene derivatives and Cys432 of RXRα are required for binding. The binding results in the potent activation of Gal4-DBD-RXRα-LBD transactivation. However, the binding inhibits the transactivation of RXRα homodimer, which might be due to the distinct conformation of RXRα homodimer induced by these nitrostyrene derivatives. Two RXRα point mutants with Cys432 substituted with Tyr and Trp, respectively, could mimic the bindings of two nitrostyrene derivatives and have the ability of autotransactivation. In studying the functional consequences of the binding, we show that these nitrostyrene derivatives could potently inhibit the TNFα/NFκB signaling pathway in a tRXRα-dependent manner. tRXRα promotes TNFα-induced NF-κB activation through its interaction with TRAF2 and enhances TNFα-induced ubiquitination of RIP1, which is strongly inhibited by nitrostyrene derivatives. The inhibition of TNFα-induced NF-κB activation results in the synergistic effect of the combination of nitrostyrene derivatives and TNFα on the induction of cancer cell apoptosis. Together, our results show a new class of RXRα modulators that induce apoptosis of cancer cells through their unique binding mode and new mechanism of action.