RESUMEN
Pancreas/duodenum homeobox protein 1 (PDX1) is an important transcription factor that regulates islet ß-cell proliferation, differentiation, and function. Reduced expression of PDX1 is thought to contribute to ß-cell loss and dysfunction in diabetes. Thus, promoting PDX1 expression can be an effective strategy to preserve ß-cell mass and function. Previously, we established a PDX1 promoter-dependent luciferase system to screen agents that can promote PDX1 expression. Natural compound tectorigenin (TG) was identified as a promising candidate that could enhance the activity of the promoter for the PDX1 gene. In this study, we first demonstrated that TG could promote the expression of PDX1 in ß-cells via activating extracellular signal-related kinase (ERK), as indicated by increased phosphorylation of ERK; this effect was observed under either normal or glucotoxic/lipotoxic conditions. We then found that TG could suppress induced apoptosis and improved the viability of ß-cells under glucotoxicity and lipotoxicity by activation of ERK and reduction of reactive oxygen species and endoplasmic reticulum (ER) stress. These effects held true in vivo as well: prophylactic or therapeutic use of TG could obviously inhibit ER stress and decrease islet ß-cell apoptosis in the pancreas of mice given a high-fat/high-sucrose diet (HFHSD), thus dramatically maintaining or restoring ß-cell mass and islet size, respectively. Accordingly, both prophylactic and therapeutic use of TG improved HFHSD-impaired glucose metabolism in mice, as evidenced by ameliorating hyperglycemia and glucose intolerance. Taken together, TG, as an agent promoting PDX1 expression exhibits strong protective effects on islet ß-cells both in vitro and in vivo.
Asunto(s)
Estrés del Retículo Endoplásmico/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Proteínas de Homeodominio/biosíntesis , Células Secretoras de Insulina/metabolismo , Isoflavonas/farmacología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Regiones Promotoras Genéticas , Transactivadores/biosíntesis , Animales , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Glucosa/metabolismo , Células HEK293 , Humanos , Masculino , Ratones , RatasRESUMEN
TSP50, a testis-specific gene encoding a serine protease-like protein, was specifically expressed in the spermatocytes of testes but abnormally activated and expressed in many different kinds of cancers. Here, we aimed to analyze the expression of TSP50 in mouse embryo and its function in early embryonic development. Firstly, the distribution of TSP50 in oocytes and embryonic development was characterized by immunofluorescence, RT-PCR and western blotting, and the results showed that TSP50 was detected at all studied stages with a dynamic expression pattern. When overexpressed TSP50 in zygotes by microinjection, the zygotes development was highly accelerated. On the contrary, knocking down TSP50 expression by RNA interference greatly retarded the zygote development. Furthermore, TSP50 expression at embryonic day 6.5 (E6.5), day 8.5 (E8.5) and day 10.5 (E10.5) were increasingly enhanced, However, the expression of TSP50 decreased gradually in the development and differentiation of cardiac myocyte from E12.5 to postnatal (P0). Additionally, we found that TSP50 expression was decreased during cardiac myocyte differentiation of P19 cells. Overexpression of TSP50 could decrease the expression of GATA-4, and knockdown of TSP50 markedly increase the expression of GATA-4. Taken together, our data indicate that TSP50 may play an important role during the process of mouse embryonic development as well as myocardial cell differentiation.
Asunto(s)
Desarrollo Embrionario/genética , Desarrollo Embrionario/fisiología , Miocitos Cardíacos/citología , Miocitos Cardíacos/enzimología , Serina Endopeptidasas/genética , Serina Endopeptidasas/metabolismo , Animales , Diferenciación Celular/genética , Diferenciación Celular/fisiología , Transición Epitelial-Mesenquimal/genética , Transición Epitelial-Mesenquimal/fisiología , Femenino , Corazón Fetal/embriología , Corazón Fetal/enzimología , Regulación del Desarrollo de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos DBA , EmbarazoRESUMEN
The pro-inflammatory cytokine interleukin 6 (IL-6), via activating its downstream JAK/STAT3 and Ras/ERK signaling pathways, is involved in cell growth, proliferation and anti-apoptotic activities in various malignancies. To screen inhibitors of IL-6 signaling, we constructed a STAT3 and ERK dual-pathway responsive luciferase reporter vector (Co.RE). Among several candidates, the natural compound 20(S)-25-methoxyl-dammarane-3ß, 12ß, 20-triol (25-OCH3-PPD, GS25) was identified to clearly inhibit the luciferase activity of Co.RE. GS25 was confirmed to indeed inhibit activation of both STAT3 and ERK pathways and expression of downstream target genes of IL-6, and to predominantly decrease the viability of HepG2 cells via induction of cell cycle arrest and apoptosis. Interestingly, GS25 showed preferential inhibition of HepG2 cell viability relative to normal liver L02 cells. Further investigation showed that GS25 could not induce apoptosis and block activation of STAT3 and ERK pathways in L02 cells as efficiently as in HepG2 cells, which may result in differential effects of GS25 on malignant and normal liver cells. In addition, GS25 was found to potently suppress the expression of endogenous STAT3 at a higher concentration and dramatically induce p38 phosphorylation in HepG2 cells, which could mediate its anti-cancer effects. Finally, we demonstrated that GS25 also inhibited tumor growth in HepG2 xenograft mice. Taken together, these findings indicate that GS25 elicits its anti-cancer effects on HepG2 cells through multiple mechanisms and has the potential to be used as an inhibitor of IL-6 signaling. Thus, GS25 may be developed as a treatment for hepatocarcinoma with low toxicity on normal liver tissues as well as other inflammation-associated diseases.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Regulación Neoplásica de la Expresión Génica , Ginsenósidos/farmacología , Hepatoblastoma/tratamiento farmacológico , Neoplasias Hepáticas/tratamiento farmacológico , Factor de Transcripción STAT3/genética , Animales , Antineoplásicos Fitogénicos/síntesis química , Apoptosis/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Proliferación Celular/efectos de los fármacos , Femenino , Genes Reporteros , Vectores Genéticos/química , Vectores Genéticos/metabolismo , Ginsenósidos/química , Células Hep G2 , Hepatoblastoma/genética , Hepatoblastoma/metabolismo , Hepatoblastoma/patología , Humanos , Interleucina-6/genética , Interleucina-6/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Luciferasas/genética , Luciferasas/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Ratones , Ratones Desnudos , Factor de Transcripción STAT3/agonistas , Factor de Transcripción STAT3/metabolismo , Carga Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas Quinasas p38 Activadas por Mitógenos/genética , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
Juglans mandshurica Maxim (Juglandaceae) is a famous folk medicine for cancer treatment and some natural compounds isolated from it have been studied extensively. Previously we isolated a type of ω-9 polyunsaturated fatty acid (JA) from the bark of J. mandshurica, however little is known about its activity and the underlying mechanisms. In this study, we studied anti-tumor activity of JA on several human cancer cell lines. Results showed that JA is cytotoxic to HepG2, MDA-MB-231, SGC-7901, A549 and Huh7 cells at a concentration exerting minimal toxic effects on L02 cells. The selective toxicity of JA was better than other classical anti-cancer drugs. Further investigation indicated that JA could induce cell apoptosis, characterized by chromatin condensation, DNA fragmentation and activation of the apoptosis-associated proteins such as Caspase-3 and PARP-1. Moreover, we investigated the cellular apoptosis pathway involved in the apoptosis process in HepG2 cells. We found that proteins involved in mitochondrion (cleaved-Caspase-9, Apaf-1, HtrA2/Omi, Bax, and Mitochondrial Bax) and endocytoplasmic reticulum (XBP-1s, GRP78, cleaved-Caspase-7 and cleaved-Caspase-12) apoptotic pathways were up-regulated when cells were treated by JA. In addition, a morphological change in the mitochondrion was detected. Furthermore, we found that JA could inhibit DNA synthesis and induce G2/M cell cycle arrest. The expression of G2-to-M transition related proteins, such as CyclinB1 and phosphorylated-CDK1, were reduced. In contrast, the G2-to-M inhibitor p21 was increased in JA-treated cells. Overall, our results suggest that JA can induce mitochondrion- and endocytoplasmic reticulum-mediated apoptosis, and G2/M phase arrest in HepG2 cells, making it a promising therapeutic agent against hepatoma.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Carcinoma Hepatocelular/patología , Ácidos Grasos Insaturados/farmacología , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Juglans/química , Neoplasias Hepáticas/patología , Medicina Tradicional China , Antineoplásicos/aislamiento & purificación , Proteína Quinasa CDC2 , Carcinoma Hepatocelular/metabolismo , Caspasa 3/metabolismo , Supervivencia Celular/efectos de los fármacos , Ciclina B1/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Quinasas Ciclina-Dependientes/metabolismo , Retículo Endoplásmico/metabolismo , Chaperón BiP del Retículo Endoplásmico , Ácidos Grasos Insaturados/aislamiento & purificación , Células Hep G2 , Humanos , Neoplasias Hepáticas/metabolismo , Mitocondrias/metabolismo , Poli(ADP-Ribosa) Polimerasa-1 , Poli(ADP-Ribosa) Polimerasas/metabolismo , Transducción de SeñalRESUMEN
Three new compounds, 3,6-dihydroxy-4,5-dimethoxy-1,8-naphalic anhydride (1), 3,4,5,6-tetrahydroxy-1,8-naphalic anhydride (2), and methyl (7E,9E)-6,11-dioxononadeca-7,9-dienoate (3), were isolated from the stem bark of Juglans mandshurica. Their structures were elucidated on the basis of spectroscopic evidence, including 1D and 2D NMR, HR-TOF-MS, and by comparison with the literature data.
Asunto(s)
Medicamentos Herbarios Chinos/aislamiento & purificación , Ácidos Grasos Insaturados/aislamiento & purificación , Juglans/química , Fenalenos/aislamiento & purificación , Medicamentos Herbarios Chinos/química , Ácidos Grasos Insaturados/química , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Fenalenos/química , Corteza de la Planta/química , Tallos de la Planta/químicaRESUMEN
Serine protease 50 (PRSS50/TSP50) is highly expressed in spermatocytes. Our study investigated its role in testicular development and spermatogenesis. Initially, PRSS50 knockdown was observed to impair DNA synthesis in spermatocytes. To further explore this, we generated PRSS50 knockout ( Prss50 -/- ) mice ( Mus musculus), which exhibited abnormal spermatid nuclear compression and reduced male fertility. Furthermore, dysplastic seminiferous tubules and decreased sex hormones were observed in 4-week-old Prss50 -/- mice, accompanied by meiotic progression defects and increased apoptosis of spermatogenic cells. Mechanistic analysis indicated that PRSS50 deletion resulted in increased phosphorylation of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and elevated levels of MAP kinase phosphatase 3 (MKP3), a specific ERK antagonist, potentially accounting for testicular dysplasia in adolescent Prss50 -/- mice. Taken together, these findings suggest that PRSS50 plays an important role in testicular development and spermatogenesis, with the MKP3/ERK signaling pathway playing a significant role in this process.
Asunto(s)
Sistema de Señalización de MAP Quinasas , Meiosis , Ratones Noqueados , Espermatozoides , Animales , Masculino , Ratones , Meiosis/fisiología , Espermatozoides/fisiología , Espermatogénesis/fisiología , Fosfatasa 6 de Especificidad Dual/genética , Fosfatasa 6 de Especificidad Dual/metabolismo , Testículo/metabolismo , Serina Endopeptidasas/genética , Serina Endopeptidasas/metabolismoRESUMEN
BACKGROUND: Interferon-gamma (IFN-gamma) and interleukin-6 (IL-6) are multifunctional cytokines that regulate immune responses, cell proliferation, and tumour development and progression, which frequently have functionally opposing roles. The cellular responses to both cytokines are activated via the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. During the past 10 years, the crosstalk mechanism between the IFN-gamma and IL-6 pathways has been studied widely and several biological hypotheses have been proposed, but the kinetics and detailed crosstalk mechanism remain unclear. RESULTS: Using established mathematical models and new experimental observations of the crosstalk between the IFN-gamma and IL-6 pathways, we constructed a new crosstalk model that considers three possible crosstalk levels: (1) the competition between STAT1 and STAT3 for common receptor docking sites; (2) the mutual negative regulation between SOCS1 and SOCS3; and (3) the negative regulatory effects of the formation of STAT1/3 heterodimers. A number of simulations were tested to explore the consequences of cross-regulation between the two pathways. The simulation results agreed well with the experimental data, thereby demonstrating the effectiveness and correctness of the model. CONCLUSION: In this study, we developed a crosstalk model of the IFN-gamma and IL-6 pathways to theoretically investigate their cross-regulation mechanism. The simulation experiments showed the importance of the three crosstalk levels between the two pathways. In particular, the unbalanced competition between STAT1 and STAT3 for IFNR and gp130 led to preferential activation of IFN-gamma and IL-6, while at the same time the formation of STAT1/3 heterodimers enhanced preferential signal transduction by sequestering a fraction of the activated STATs. The model provided a good explanation of the experimental observations and provided insights that may inform further research to facilitate a better understanding of the cross-regulation mechanism between the two pathways.
Asunto(s)
Interferón gamma/farmacología , Interleucina-6/farmacología , Modelos Biológicos , Quinasas Janus/metabolismo , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT3/metabolismo , Transducción de Señal , Proteínas Supresoras de la Señalización de Citocinas/metabolismoRESUMEN
BACKGROUND: Somitogenesis is a fundamental characteristic feature of development in various animal embryos. Molecular evidence has proved that the Notch and Wnt pathways play important roles in regulating the process of somitogenesis and there is crosstalk between these two pathways. However, it is difficult to investigate the detailed mechanism of these two pathways and their interactions in somitogenesis through biological experiments. In recent years some mathematical models have been proposed for the purpose of studying the dynamics of the Notch and Wnt pathways in somitogenesis. Unfortunately, only a few of these models have explored the interactions between them. RESULTS: In this study, we have proposed three mathematical models for the Notch signalling pathway alone, the Wnt signalling pathway alone, and the interactions between them. These models can simulate the dynamics of the Notch and Wnt pathways in somitogenesis, and are capable of reproducing the observations derived from wet experiments. They were used to investigate the molecular mechanisms of the Notch and Wnt pathways and their crosstalk in somitogenesis through the model simulations. CONCLUSIONS: Three mathematical models are proposed for the Notch and Wnt pathways and their interaction during somitogenesis. The simulations demonstrate that the extracellular Notch and Wnt signals are essential for the oscillating expressions of both Notch and Wnt target genes. Moreover, the internal negative feedback loops and the three levels of crosstalk between these pathways play important but distinct roles in maintaining the system oscillation. In addition, the results of the parameter sensitivity analysis of the models indicate that the Notch pathway is more sensitive to perturbation in somitogenesis.
Asunto(s)
Embrión no Mamífero/metabolismo , Modelos Teóricos , Receptores Notch/metabolismo , Transducción de Señal , Somitos , Proteínas Wnt/metabolismo , AnimalesRESUMEN
A novel series of polyphenols 4-9 were synthesized by the reaction of catechol with dehydroabietylamine derivatives. The antitumor activities of these compounds against L02 and HepG2 cells were investigated. Among them, compounds 4, 5, and 9 can inhibit HepG2 cells viability, but have lower inhibitory effect on L02 cells in the same concentration, indicating their potential for further development. Meanwhile, the novel series of polyphenols exhibited stronger radical-scavenging activities than the control groups.
Asunto(s)
Antineoplásicos/farmacología , Antioxidantes/farmacología , Diterpenos/farmacología , Depuradores de Radicales Libres/farmacología , Polifenoles/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Antioxidantes/síntesis química , Antioxidantes/química , Compuestos de Bifenilo/farmacología , Catecoles/química , Diterpenos/síntesis química , Diterpenos/química , Depuradores de Radicales Libres/síntesis química , Depuradores de Radicales Libres/química , Células Hep G2 , Humanos , Modelos Químicos , Estructura Molecular , Picratos/farmacología , Polifenoles/síntesis química , Polifenoles/química , Relación Estructura-ActividadRESUMEN
A new 2,5-diketopiperazine, (R)-2-(2-(furan-2-yl)-oxoethyl)-octahydropyrrolo[1,2-a]pyrazine-1,4-dione, and seven known compounds were isolated from the ethyl acetate extract of liquid fermentation broth of Armillaria mellea. The structures of the isolated compounds were established from NMR and HR-MS data. The absolute configuration of the new compound was established by comparing the experimental electronic circular dichroism (ECD) spectrum with the calculated ECD data.
Asunto(s)
Armillaria/química , Dicetopiperazinas/aislamiento & purificación , Medicamentos Herbarios Chinos/aislamiento & purificación , Dicroismo Circular , Dicetopiperazinas/química , Medicamentos Herbarios Chinos/química , Fermentación , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , EstereoisomerismoRESUMEN
A series of novel dehydroabietylamine derivatives containing tricyclic diterpene structures were synthesized. The antitumor activities of these compounds against L02, Hey-1B and HepG2 cells were investigated. Significant activity was discovered forfourteen analogs. Meanwhile these compounds exhibit DNA cleavage activities on plasmid DNA (Escherichia coli), which depend on the Schiff base structure and the substituent of the aromatic moiety. Our findings present further information on the relationship between the chemical structure, biological function and DNA cleavage characteristics.
Asunto(s)
Antineoplásicos/síntesis química , Antineoplásicos/farmacología , División del ADN/efectos de los fármacos , Diterpenos/síntesis química , Diterpenos/farmacología , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Indicadores y Reactivos , Hierro/químicaRESUMEN
Juglanthraquinone C (1,5-dihydroxy-9,10-anthraquinone-3-carboxylic acid, JC), a naturally occurring anthraquinone isolated from the stem bark of Juglans mandshurica, shows strong cytotoxicity in various human cancer cells in vitro. Here, we first performed a structure-activity relationship study of six anthraquinone compounds (JC, rhein, emodin, aloe-emodin, physcion and chrysophanol) to exploit the relationship between their structural features and activity. The results showed that JC exhibited the strongest cytotoxicity of all compounds evaluated. Next, we used JC to treat several human cancer cell lines and found that JC showed an inhibitory effect on cell viability in dose-dependent (2.5-10 µg/ml JC) and time-dependent (24-48 h) manners. Importantly, the inhibitory effect of JC on HepG2 (human hepatocellular carcinoma) cells was more significant as shown by an IC(50) value of 9 ± 1.4 µg/ml, and 36 ± 1.2 µg/ml in L02 (human normal liver) cells. Further study suggested that JC-induced inhibition HepG2 cell proliferation was associated with S phase arrest, decreased protein expression of proliferation marker Ki67, cyclin A and cyclin-dependent kinase (CDK) 2, and increased expression of cyclin E and CDK inhibitory protein Cip1/p21. In addition, JC significantly triggered apoptosis in HepG2 cells, which was characterized by increased chromatin condensation and DNA fragmentation, activation of caspase-9 and -3, and induction of a higher Bax/Bcl2 ratio. Collectively, our study demonstrated that JC can efficiently inhibit proliferation and induce apoptosis in HepG2 cells.
Asunto(s)
Antraquinonas/farmacología , Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Medicamentos Herbarios Chinos/farmacología , Juglans/química , Puntos de Control de la Fase S del Ciclo Celular/efectos de los fármacos , Caspasa 3/metabolismo , Caspasa 9/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Activación Enzimática , Células Hep G2 , Humanos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Relación Estructura-Actividad , Proteína X Asociada a bcl-2/metabolismoRESUMEN
TSP50 (testes-specific protease 50) is a testis-specific expression protein, which is expressed abnormally at high levels in breast cancer tissues. This makes it an attractive molecular marker and a potential target for diagnosis and therapy; however, the biological function of TSP50 is still unclear. In the present study, we show that overexpression of TSP50 in CHO (Chinese-hamster ovary) cells markedly increased cell proliferation and colony formation. Mechanistic studies have revealed that TSP50 can enhance the level of TNFα (tumour necrosis factor α)- and PMA-induced NF-κB (nuclear factor κB)-responsive reporter activity, IκB (inhibitor of NF-κB) α degradation and p65 nuclear translocation. In addition, the knockdown of endogenous TSP50 in MDA-MB-231 cells greatly inhibited NF-κB activity. Co-immunoprecipitation studies demonstrated an interaction of TSP50 with the NF-κB-IκBα complex, but not with the IKK (IκB kinase) α/ß-IKKγ complex, which suggested that TSP50, as a novel type of protease, promoted the degradation of IκBα proteins by binding to the NF-κB-IκBα complex. Our results also revealed that TSP50 can enhance the expression of NF-κB target genes involved in cell proliferation. Furthermore, overexpression of a dominant-negative IκB mutant that is resistant to proteasome-mediated degradation significantly reversed TSP50-induced cell proliferation, colony formation and tumour formation in nude mice. Taken together, the results of the present study suggest that TSP50 promotes cell proliferation, at least partially, through activation of the NF-κB signalling pathway.
Asunto(s)
Proliferación Celular , FN-kappa B/metabolismo , Serina Endopeptidasas/fisiología , Transducción de Señal/fisiología , Animales , Células CHO , Línea Celular Tumoral , Cricetinae , Cricetulus , Células HEK293 , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , FN-kappa B/fisiología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Insulin-like growth factor 1 receptor (IGF1R) is an attractive drug target for cancer therapy and research on IGF1R inhibitors has had success in clinical trials. A particular challenge in the development of specific IGF1R inhibitors is interference from insulin receptor (IR), which has a nearly identical sequence. A few potent inhibitors that are selective for IGF1R have been discovered experimentally with the aid of computational methods. However, studies on the rapid identification of IGF1R-selective inhibitors using virtual screening and confidence-level inspections of ligands that show different interactions with IGF1R and IR in docking analysis are rare. In this study, we established virtual screening and binding-mode prediction workflows based on benchmark results of IGF1R and several kinase receptors with IGF1R-like structures. We used comprehensive analysis of the known complexes of IGF1R and IR with their binding ligands to screen specific IGF1R inhibitors. Using these workflows, 17 of 139,735 compounds in the NCI (National Cancer Institute) database were identified as potential specific inhibitors of IGF1R. Calculations of the potential of mean force (PMF) with GROMACS were further conducted for three of the identified compounds to assess their binding affinity differences towards IGF1R and IR.
Asunto(s)
Antineoplásicos/química , Bases de Datos de Compuestos Químicos , Simulación del Acoplamiento Molecular , Proteínas de Neoplasias/antagonistas & inhibidores , Receptores de Somatomedina/antagonistas & inhibidores , Ensayos de Selección de Medicamentos Antitumorales , Humanos , National Cancer Institute (U.S.) , Proteínas de Neoplasias/química , Receptor IGF Tipo 1 , Receptores de Somatomedina/química , Estados UnidosRESUMEN
The title compound {systematic name: 4-[(3S,5S,8R,9S,10R,13R,14S,17S)-3,5,14-trihy-droxy-10,13-dimethyl-hexa-deca-hydro-1H-cyclo-penta-[a]phenanthren-17-yl]furan-2(5H)-one}, C(23)H(34)O(5), was isolated from the roots of Periploca sepium Bunge, a famous Chinese traditional herbal medicine. The three six-membered rings adopt chair conformations, the cyclo-pentane ring displays an approximate envelope conformation (with the C atom bearing the methyl substituent at the flap) and the five-membered lactone ring adopts an essentially planar [maximum deviation of 0.004â (8)â Å] conformation. In the crystal, mol-ecules are linked into helical chains along [010] by O-Hâ¯O hydrogen bonds and weak C-Hâ¯O inter-actions. Two intra-molecular O-Hâ¯O hydrogen bonds are also present.
RESUMEN
The structural characteristics and immunoregulatory activities of neutral heteropolysaccharide (AVRP-N) separated from the roots of Apocynum venetum L. were extensively investigated. The results showed that the weight average molecular mass (Mw) of AVRP-N was 6.430 × 103 Da. Moreover, the backbone is composed of natural acetylated (1 â 4)-ß-D-Man and (1 â 5)-α-L-Ara domains. The mannan is composed of â4)-ß-D-Manp-(1â, â4)-ß-D-Glcp-(1â, and the terminal group α-D-Galp-(1â attached to â4,6)-ß-D-Manp-(1â at O-6. Araban is composed of â5)-α-L-Araf-(1â; the terminal group α-L-Araf-(1âattached toâ2,3,5)-α-L-Araf-(1â at O-2, O-3 and â3,5)-α-L-Araf-(1â at O-3. In addition, the senior structure shows that AVRP-N has a triple-helix conformation. Furthermore, AVRP-N exhibited immunomodulatory effects, which could significantly regulate the proliferation of mouse splenic lymphocytes by enhancing the secretion of the cytokines (IFN-γ, IL-2, IL-4, and IL-10). Our results provide new structural and immunoregulatory information for natural polysaccharides derived from Apocynum venetum L.
Asunto(s)
Apocynum , Ratones , Animales , Polisacáridos/farmacología , Polisacáridos/química , Mananos , Raíces de Plantas , Peso MolecularRESUMEN
Crassostrea sikamea (C.sikamea) is an important edible and medicinal seafood in China. In the present study, a compound named flazin was separated and identified from the ethyl acetate extract of C.sikamea (EAECs) for the first time. In addition, the 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetra zolium (MTS) assay revealed that EAECs and flazin inhibited the transformation of splenic lymphocytes in vitro. Moreover, flazin (20 µg·mL-1) altered the populations of splenic lymphocyte subtypes. Real-time quantitative PCR (RT-qPCR) analysis and enzyme-linked immunosorbent assay (ELISA) showed that flazin suppressed the mRNA expression and secretion of TNF-α and IL-2, and reversed Concanavalin A (ConA)-induced mRNA up-regulation and protein secretion of TNF-α and IL-2. Western blot results showed that flazin reversed ConA-induced increases in p-ERK1/2 and p-p38 in splenocytes. In conclusion, flazin exhibits effective immunomodulatory function and may be useful for treating immune-related disorders, which indicates the application potential of C.sikamea as a functional food or immunomodulator.
Asunto(s)
Crassostrea , Animales , Carbolinas , Furanos , Linfocitos , Ratas , Ratas Sprague-Dawley , BazoRESUMEN
Previous studies demonstrated that the expression of testes-specific protease 50 (TSP50) was increased in breast cancer cells and that overexpression of TSP50 can promote tumorigenesis. Thus, it is important to identify the regulatory mechanisms of TSP50 for tumor therapy. In this study, we elucidated the mechanism underlying TSP50 downregulation by basic fibroblast growth factor (bFGF). We used MDA-MB-231 and HEK293T cell lines to address this issue. RT-PCR and promoter activity assays indicated that bFGF downregulates TSP50 expression via transcriptional activation. We next investigated the signaling pathway that mediated the effect of bFGF on TSP50 transcription, and identified that bFGF induced the phosphorylation of ERK and Sp1. An ERK inhibitor suppressed Sp1 phosphorylation and bFGF-reduced TSP50 expression at the mRNA level. In addition, the dominant negative (DN) mutants of ERK and Sp1 both suppressed the reduction of TSP50 by bFGF. Deletion and mutation analyses indicated that the Sp1 site, located within the +237/+239 region of the human TSP50 promoter, is the major responsive element for bFGF. Taken together, our results strongly suggest that bFGF mediates TSP50 downregulation by ERK activation, leading to the phosphorylation of Sp1 in this process.
Asunto(s)
Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Factor 2 de Crecimiento de Fibroblastos/farmacología , Serina Endopeptidasas/metabolismo , Transducción de Señal/efectos de los fármacos , Factor de Transcripción Sp1/metabolismo , Línea Celular/efectos de los fármacos , Regulación hacia Abajo/efectos de los fármacos , Activación Enzimática , Inhibidores Enzimáticos/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/genética , Humanos , Regiones Promotoras Genéticas , Serina Endopeptidasas/genética , Factor de Transcripción Sp1/genética , Activación TranscripcionalRESUMEN
Earlier studies identified testes-specific protease 50 (TSP50), which encodes a threonine protease, and showed that it was abnormally reactivated in many breast cancer biopsies. Further, it was shown to be negatively regulated by the p53 gene. However, little is known about the biological function of TSP50. In this study, we applied RNA interference to knockdown TSP50 gene expression in P19 murine embryonal carcinoma stem cells and tested whether this modulated the cell phenotype. The results showed that downregulation of TSP50 expression not only reduced cell proliferation, colony formation, and migration but also induced cell apoptosis. Further investigation revealed that knockdown of TSP50 resulted in greater sensitivity to doxorubicin-induced apoptosis and that activation of caspase-3 was involved in this process.
Asunto(s)
Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Serina Endopeptidasas/fisiología , Animales , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Regulación hacia Abajo , Doxorrubicina/farmacología , Técnicas de Silenciamiento del Gen , Ratones , Interferencia de ARN , Serina Endopeptidasas/genética , Proteína p53 Supresora de Tumor/fisiologíaRESUMEN
Psoriasis is considered an immune-mediated inflammatory skin disorder that affects the quality of life of nearly four percent of the world population. Considering the side effects of existing therapeutic drugs and the urgent need for new drug development, we screened more than 250 traditional Chinese medicine compounds to identify drugs that significantly reduced the viability of human HaCaT keratinocytes, a psoriasis-related model cell line. Convallatoxin (CNT) was found to be a highly effective inhibitor of HaCaT cell viability. Subsequent mechanistic studies revealed that CNT induced HaCaT cell death by necroptosis rather than by apoptosis. CNT destroyed the membrane integrity of HaCaT cells, as detected by nuclear propidium iodide (PI) staining and lactate dehydrogenase (LDH) release. Additionally, the intercellular levels of adenosine triphosphate (ATP) were lower in HaCaT cells treated with CNT than in control HaCaT cells, and typical necroptosis-associated characteristics were observed by electron microscopy in cells treated with CNT. Furthermore, compared with control HaCaT cells, CNT-treated HaCaT cells produced more reactive oxygen species (ROS), but this effect was inhibited by the antioxidants N-acetyl-cysteine (NAC), diphenyleneiodonium chloride (DPI), and apocynin and the necroptosis inhibitor Nec-1. In addition, antioxidant treatment attenuated necroptotic cell death, suggesting that CNT-induced HaCaT necroptosis is mediated by oxidative stress. More importantly, CNT ameliorated skin lesions and inflammation in imiquimod (IMQ)- and 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced psoriasis-like mouse models. In conclusion, our results demonstrate that CNT is cytotoxic against HaCaT cells in vitro and exerts antipsoriatic activities in two mouse models of psoriasis in vivo, making CNT a potential promising candidate drug for future research.