Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 67
Filtrar
Mais filtros

País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Nature ; 574(7777): 223-227, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31597974

RESUMO

High-entropy alloys are a class of materials that contain five or more elements in near-equiatomic proportions1,2. Their unconventional compositions and chemical structures hold promise for achieving unprecedented combinations of mechanical properties3-8. Rational design of such alloys hinges on an understanding of the composition-structure-property relationships in a near-infinite compositional space9,10. Here we use atomic-resolution chemical mapping to reveal the element distribution of the widely studied face-centred cubic CrMnFeCoNi Cantor alloy2 and of a new face-centred cubic alloy, CrFeCoNiPd. In the Cantor alloy, the distribution of the five constituent elements is relatively random and uniform. By contrast, in the CrFeCoNiPd alloy, in which the palladium atoms have a markedly different atomic size and electronegativity from the other elements, the homogeneity decreases considerably; all five elements tend to show greater aggregation, with a wavelength of incipient concentration waves11,12 as small as 1 to 3 nanometres. The resulting nanoscale alternating tensile and compressive strain fields lead to considerable resistance to dislocation glide. In situ transmission electron microscopy during straining experiments reveals massive dislocation cross-slip from the early stage of plastic deformation, resulting in strong dislocation interactions between multiple slip systems. These deformation mechanisms in the CrFeCoNiPd alloy, which differ markedly from those in the Cantor alloy and other face-centred cubic high-entropy alloys, are promoted by pronounced fluctuations in composition and an increase in stacking-fault energy, leading to higher yield strength without compromising strain hardening and tensile ductility. Mapping atomic-scale element distributions opens opportunities for understanding chemical structures and thus providing a basis for tuning composition and atomic configurations to obtain outstanding mechanical properties.

2.
Nucleic Acids Res ; 51(7): 3150-3165, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-36869674

RESUMO

DNA double-strand breaks (DSBs) are functionally linked to genomic instability in spermatocytes and to male infertility. The heavy metal cadmium (Cd) is known to induce DNA damage in spermatocytes by unknown mechanisms. Here, we showed that Cd ions impaired the canonical non-homologous end-joining (NHEJ) repair pathway, but not the homologous recombination (HR) repair pathway, through stimulation of Ser2056 and Thr2609 phosphorylation of DNA-PKcs at DSB sites. Hyper-phosphorylation of DNA-PKcs led to its premature dissociation from DNA ends and the Ku complex, preventing recruitment of processing enzymes and further ligation of DNA ends. Specifically, this cascade was initiated by the loss of PP5 phosphatase activity, which results from the dissociation of PP5 from its activating ions (Mn), that is antagonized by Cd ions through a competitive mechanism. In accordance, in a mouse model Cd-induced genomic instability and consequential male reproductive dysfunction were effectively reversed by a high dosage of Mn ions. Together, our findings corroborate a protein phosphorylation-mediated genomic instability pathway in spermatocytes that is triggered by exchange of heavy metal ions.


Assuntos
Cádmio , Instabilidade Genômica , Infertilidade Masculina , Espermatócitos , Animais , Humanos , Masculino , Camundongos , Cádmio/toxicidade , DNA/metabolismo , Reparo do DNA por Junção de Extremidades , Reparo do DNA , Instabilidade Genômica/efeitos dos fármacos , Infertilidade Masculina/genética , Infertilidade Masculina/metabolismo , Íons/metabolismo , Fosforilação , Reparo de DNA por Recombinação , Espermatócitos/efeitos dos fármacos
3.
Fish Shellfish Immunol ; 151: 109715, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38909637

RESUMO

Red-spotted grouper nervous necrosis virus (RGNNV) is a major viral pathogen of grouper and is able to antagonize interferon responses through multiple strategies, particularly evading host immune responses by inhibiting interferon responses. Ovarian tumor (OTU) family proteins are an important class of DUBs and the underlying mechanisms used to inhibit interferon pathway activation are unknown. In the present study, primers were designed based on the transcriptome data, and the ovarian tumor (OTU) domain-containing ubiquitin aldehyde-binding protein 1 (OTUB1) and OTUB2 genes of Epinephelus coioides (EcOTUB1 and EcOTUB2) were cloned and characterized. The homology alignment showed that both EcOTUB1 and EcOTUB2 were most closely related to E. lanceolatus with 98 % identity. Both EcOTUB1 and EcOTUB2 were distributed to varying degrees in grouper tissues, and the transcript levels were significantly up-regulated following RGNNV stimulation. Both EcOTUB1 and EcOTUB2 promoted replication of RGNNV in vitro, and inhibited the promoter activities of interferon stimulated response element (ISRE), nuclear transcription factors kappaB (NF-κB) and IFN3, and the expression levels of interferon related genes and proinflammatory factors. Co-immunoprecipitation experiments showed that both EcOTUB1 and EcOTUB2 could interact with TRAF3 and TRAF6, indicating that EcOTUB1 and EcOTUB2 may play important roles in interferon signaling pathway. The results will provide a theoretical reference for the development of novel disease prevention and control techniques.

4.
Prostate ; 83(15): 1415-1429, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37565264

RESUMO

BACKGROUND: The discovery of androgen receptor (AR) having transrepression effects completes the circle of its functionalities as a typical transcription factor, which intrinsically bears dual functions of activation and repression linked to co-factor competition and redistribution. Indeed, AR dual functions are exemplified by locus-wide regulation of the oncogenic 8q24-MYC region. METHODS: RT-qPCR assay and public RNA-profiling datasets were used to assess MYC transcription in androgen-sensitive cell lines. Public ChIP-seq and RNA-Seq datasets were computed to evaluate AR-MYC direct and indirect signatures. Gene sets in typical MYC and AR pathways were monitored to validate their cross-talks. Bio-informatics and chromosome conformation capture (3C) assay were performed in the AR gene locus to examine androgen-elicited distal regulation. Finally, co-factor re-distribution were globally tracked between AR and MYC binding sites. RESULTS: In this report, we found MYC responded negatively to androgen with hypersensitivity, rivaling AR natural functions as an innate androgen effector. Furthermore, both direct and indirect AR and MYC transcriptional programs were actively in equilibration. With established androgen-mediated versus MYC-mediated gene subsets, we validated AR and MYC pathways were both bidirectional and extensively entangled. In addition, we determined that the AR gene locus resembled the MYC gene region and both loci were androgen-repressed via epigenetics and chromatin architectural alterations. Significantly, transcriptional factor profiling along the prostate cancer (PCa) genome exposed that PCa transcriptomes were dynamically equilibrated between AR-binding site and MYC-binding site. CONCLUSION: Together, our findings stratified AR-MYC interactions that are extensively wired and intricately organized to compensate for essential PCa transcriptional programs and neutralize excessive signaling.


Assuntos
Neoplasias da Próstata , Receptores Androgênicos , Masculino , Humanos , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Androgênios/metabolismo , Transcriptoma , Linhagem Celular Tumoral , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Fatores de Transcrição/genética , Regulação Neoplásica da Expressão Gênica
5.
J Transl Med ; 21(1): 716, 2023 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-37828515

RESUMO

BACKGROUND: Androgen receptor (AR) activation and repression dual-functionality only became known recently and still remains intriguing in prostate cancer (PCa). MYC is a prominent oncogene that functionally entangles with AR signaling in PCa. Further exploration of AR regulatory mechanisms on MYC gene transcription bears clinical and translation significance. METHODS: Bioinformatics analysis of PCa cell line and clinical RNA-Seq and ChIP-Seq (chromatin immunoprecipitation-sequencing) datasets to anchor interactions of AR and MYC transcriptional networks. ChIP-qPCR and 3C (chromosome conformation capture) analyses to probe MYC distal regulation by AR binding sites (ABSs). CRISPR/Cas9-mediated genome-editing to specify functions of ABS within the 8q24-MYC locus on androgen-mediated MYC transcription. Global FoxA1 and HoxB13 distribution profiling to advance AR transcriptional mechanisms. RESULTS: Here we recognize AR bi-directional transcription mechanisms by exploiting the prominent 8q24-MYC locus conferring androgen hyper-sensitivity. At ~ 25 Kb downstream of the MYC gene, we identified an undefined ABS, P10. By chromatin analyses, we validated androgen-dependent spatial interaction between P10 and MYC-Promoter (MYC-Pro) and temporal epigenetic repression of these MYC-proximal elements. We next designed a CRISPR/Cas9-mediated double genomic knock-out (KO) strategy to show that P10-KO slightly lessened androgen-elicited MYC transrepression in LNCaP-AR cells. In similar genomic editing assays, androgen-mediated MYC repression became slightly deepened upon KO of P11, an ABS in the PVT1 gene locus highly enriched in AR-binding motifs and peaks. We also investigated multiple ABSs in the established PCAT1 super-enhancer that distally interacts with MYC-Pro for transactivation, with each KO pool consistently shown to relieve androgen-elicited MYC repression. In the end, we systemically assessed androgen effects in the 8q24-MYC locus and along PCa genome to generalize H3K27ac and BRD4 re-distribution from pioneer factors (FoxA1 and HoxB13) to AR sites. CONCLUSION: Together, we reconciled these observations by unifying AR dual-functions that are mechanistically coupled to and equilibrated by co-factor redistribution.


Assuntos
Neoplasias da Próstata , Proteínas Proto-Oncogênicas c-myc , Receptores Androgênicos , Humanos , Masculino , Androgênios , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Proteínas Nucleares/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética
6.
Future Oncol ; 18(17): 2053-2062, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35354274

RESUMO

Aim: Data for avelumab (anti-PD-L1 antibody) in Chinese patients are limited. Patients & methods: Phase I/Ib, open-label, dose-escalation study of Chinese patients with advanced solid tumors. Primary study objectives were to evaluate the maximum tolerated dose (MTD) and pharmacokinetics (PK) of avelumab. Results: 24 patients received avelumab 3 mg/kg every 2 weeks (Q2W; n = 3), 10 mg/kg Q2W (n = 7), 20 mg/kg Q2W (n = 6) or 10 mg/kg weekly for 12 weeks and then Q2W thereafter (n = 8). MTD was not reached. Avelumab exposure was increased in higher dose groups. Partial responses occurred in two patients (confirmed in one patient); best overall response was stable disease in nine patients. Conclusion: Data for avelumab in Chinese patients with advanced solid tumors were consistent with previous global studies.


Avelumab is a form of medicine that falls under the category of immunotherapy. This means that it can help the immune system find and destroy cancer cells. In this study, researchers looked at the safety of avelumab in a small group of Chinese people with different types of cancer. Researchers also looked at blood levels of avelumab after treatment. Different doses of avelumab were given to different groups of people. Overall, study results for avelumab in Chinese people were similar to results from earlier studies in other countries.  Clinical trial registration: NCT03523390 (ClinicalTrials.gov).


Assuntos
Anticorpos Monoclonais , Neoplasias , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais/farmacocinética , Anticorpos Monoclonais Humanizados/efeitos adversos , China/epidemiologia , Humanos , Neoplasias/tratamento farmacológico
7.
J Nanobiotechnology ; 19(1): 85, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33766052

RESUMO

BACKGROUND: Graphene oxide (GO), a novel carbon-based nanomaterial, has promising applications in biomedicine. However, it induces potential cytotoxic effects on the gastrointestinal (GI) tract cells, and these effects have been largely uncharacterized. The present study aimed to explore the toxic effects of GO on the intestinal tract especially under pre-existing inflammatory conditions, such as inflammatory bowel disease (IBD), and elucidate underlying mechanisms. RESULTS: Our findings indicated that oral gavage of GO worsened acute colitis induced by 2.5% dextran sodium sulfate (DSS) in mice. In vitro, GO exacerbated DSS-induced inflammation and apoptosis in the FHC cell line, an ideal model of intestinal epithelial cells (IECs). Further, the potential mechanism underlying GO aggravated mice colitis and cell inflammation was explored. Our results revealed that GO treatment triggered apoptosis in FHC cells through the activation of reactive oxygen species (ROS)/AMP-activated protein kinase (AMPK)/p53 pathway, as evidenced by the upregulation of cytochrome c (Cytc), Bax, and cleaved caspase-3 (c-cas3) and the downregulation of Bcl-2. Interestingly, pretreatment with an antioxidant, N-acetyl-L-cysteine, and a specific inhibitor of AMPK activation, Compound C (Com.C), effectively inhibited GO-induced apoptosis in FHC cells. CONCLUSIONS: Our data demonstrate that GO-induced IECs apoptosis via ROS/AMPK/p53 pathway activation accounts for the exacerbation of colitis in vivo and aggravation of inflammation in vitro. These findings provide a new insight into the pathogenesis of IBD induced by environmental factors. Furthermore, our findings enhance our understanding of GO as a potential environmental toxin, which helps delineate the risk of exposure to patients with disturbed intestinal epithelial barrier/inflammatory disorders such as IBD.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Apoptose/efeitos dos fármacos , Colite/tratamento farmacológico , Sulfato de Dextrana/efeitos adversos , Grafite/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteína Supressora de Tumor p53/metabolismo , Animais , Caspase 3 , Sobrevivência Celular , Colite/patologia , Colo , Citocinas , Feminino , Grafite/química , Inflamação , Doenças Inflamatórias Intestinais , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas c-bcl-2
8.
Med Sci Monit ; 27: e932339, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33762559

RESUMO

An editorial decision has been made to retract this manuscript due to breach of publishing guidelines, following the identification of non-original and manipulated figures. Reference: Jingbao Zhang, Yanfei Gao, Changbo Ma, Yi Wang: Murrayanine Induces Cell Cycle Arrest, Oxidative Stress, and Inhibition of Phosphorylated p38 Expression in A549 Lung Adenocarcinoma Cells. Med Sci Monit 2019; 25:2002-2008. 10.12659/MSM.913873.

9.
Biochem Biophys Res Commun ; 522(4): 924-930, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-31806371

RESUMO

Lysine-specific demethylase 1 (LSD1) is a well characterized transcriptional regulator functioning on the chromatin to remove mono- and di-methyl groups from lysine 4 or lysine 9 of histone 3 (H3K4 or H3K9). LSD1 also has non-transcriptional activities via targeting non-histone substrates that participate in diverse biological processes. In this report, we determined that LSD1 negatively regulates autophagy in skeletal muscle cells by promoting PTEN degradation in a transcription-independent mechanism. In C2C12 cells, LSD1 inhibition or depletion significantly induced the initiation of autophagy; and autophagy resulted from LSD1 inhibition is associated with AKT/mTORC1 inactivation. Notably, the proteins of PTEN, a prominent repressive AKT modulator, are stabilized by LSD1 inhibition despite a decrease of its mRNA levels. Further data demonstrated that LSD1 interacts with PTEN protein and enhances its ubiquitination and degradation. Together, our findings identify a novel biological function of LSD1 in autophagy, mediated by regulating the stability of PTEN and the activity of AKT/mTORC1.


Assuntos
Autofagia , Histona Desmetilases/metabolismo , Mioblastos/citologia , Mioblastos/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , Proteólise , Animais , Linhagem Celular , Ativação Enzimática , Estabilidade Enzimática , Histona Desmetilases/antagonistas & inibidores , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Mioblastos/ultraestrutura , PTEN Fosfo-Hidrolase/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transcrição Gênica , Ubiquitinação
10.
Nat Immunol ; 9(5): 533-41, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18362886

RESUMO

Despite rapid progress in elucidating the molecular mechanisms of activation of the kinase IKK, the processes that regulate IKK deactivation are still unknown. Here we demonstrate that CUE domain-containing 2 (CUEDC2) interacted with IKKalpha and IKKbeta and repressed activation of the transcription factor NF-kappaB by decreasing phosphorylation and activation of IKK. Notably, CUEDC2 also interacted with GADD34, a regulatory subunit of protein phosphatase 1 (PP1). We found that IKK, CUEDC2 and PP1 existed in a complex and that IKK was released from the complex in response to inflammatory stimuli such as tumor necrosis factor. CUEDC2 deactivated IKK by recruiting PP1 to the complex. Therefore, CUEDC2 acts as an adaptor protein to target IKK for dephosphorylation and inactivation by recruiting PP1.


Assuntos
Proteínas de Transporte/metabolismo , Quinase I-kappa B/metabolismo , Proteínas de Membrana/metabolismo , Proteína Fosfatase 1/metabolismo , Proteínas Repressoras/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Animais , Antígenos de Diferenciação/genética , Antígenos de Diferenciação/metabolismo , Proteínas de Transporte/imunologia , Domínio Catalítico , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Células Cultivadas , Feminino , Humanos , Quinase I-kappa B/química , Inflamação/imunologia , Interleucina-6/biossíntese , Interleucina-6/genética , Macrófagos/imunologia , Macrófagos/metabolismo , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/genética , NF-kappa B/metabolismo , Fosforilação , Ligação Proteica , Proteínas Repressoras/imunologia , Regulação para Cima
11.
Phys Chem Chem Phys ; 21(17): 8633-8644, 2019 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-30830131

RESUMO

Salt induced micelle-to-vesicle transitions of ionic surfactants depend on the surfactant chain length, headgroup structure, counterion type and concentration, but the interfacial molarities of counterions and water that balance the hydrophobic effect are difficult to determine. In anionic micelles of twin-tailed sodium bis(2-ethylhexyl)sulfosuccinate (AOT), the chemical trapping (CT) method provides estimates of the interfacial molarities of anionic headgroups (RSO3-m) and neutral (H2Om) nucleophiles during salt induced transitions of AOT micelles to vesicles. Product yields were measured by HPLC from the competitive dediazoniation reaction using a specially designed hydrophobic probe, 4-hexadecyl-2,6-dimethylbenzenediazonium cation, 16-ArN2+. The reactions were run at constant concentration of 15 mM AOT mixed with 0 to 50 mM added salts, containing cations of different sizes and valences including tetraalkylammonium cations (MR4+, R = 1-4) and metal cations (M1-3+). Parallel reactions in aqueous salt solutions with a short chain analog, 1-ArN2+, were used as references to calculate interfacial molarities. Aggregates were structurally characterized by TEM and DLS. Typically, interfacial RSO3- molarities increase with added salts from 1 to 2 M and water molarities decrease from about 40 to 20 M with the micelle to vesicle transition. These changes are consistent with the ion-pair/hydration model, in which the added cations form neutral but polar ion-pairs with RSO3- that have a lower demand for hydration and water was released into the surrounding aqueous phase. The extent of ion-pairing increases with cation size, charge and hydrophobicity and decreases with interfacial water molarity, which permits tighter interfacial packing and vesicle formation at lower added salt concentrations.

12.
Med Sci Monit ; 25: 2002-2008, 2019 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-30879017

RESUMO

BACKGROUND Murrayanine is a carbazole alkaloid derived from Murraya koenigii, which has been used in traditional Chinese medicine in the treatment of cancer. This study aimed to investigate the effects of murrayanine on human lung adenocarcinoma cells in vitro and to investigate the mechanisms of its action. MATERIAL AND METHODS A549 human lung adenocarcinoma cells and MRC-5 human lung fibroblasts were grown in culture, and an MTT assay determined cell viability. Cells were treated for 24 h with increasing doses of murrayanine (0, 9, 18, and 36 µM). Fluorescence, using 4', 6-diamidino-2-phenylindole (DAPI), acridine orange, ethidium bromide, and propidium iodide (PI), were used for the detection of apoptosis. The cell cycle was studied with fluorescence-activated cell sorting (FACS), and Western blot evaluated protein expression. RESULTS Murrayanine treatment resulted in significant dose-dependent inhibition of the growth of A549 cells (p<0.05), with an IC50 of 9 µM, and arrested the cells at the G2/M phase of the cell cycle, reduced the expression of cyclin D and E, CDK2, 4, and 6, and increased the expression of p21 and p27. Murrayanine treatment increased apoptosis of the A549 cells and increased cleaved of caspase-3 and caspase-9, and the Bax/Bcl-2 ratio. Murrayanine treatment increased levels of reactive oxygen species (ROS), disrupted the mitochondrial membrane potential, inhibited invasion, and inhibited phosphorylation of p38 mitogen-activated protein kinase (MAPK) of the A549 cells. CONCLUSIONS Murrayanine induced cell cycle arrest, oxidative stress, and inhibited the expression of phosphorylated p38 in A549 adenocarcinoma cells.


Assuntos
Adenocarcinoma de Pulmão/tratamento farmacológico , Carbazóis/farmacologia , Células A549 , Adenocarcinoma/tratamento farmacológico , Apoptose/efeitos dos fármacos , Carbazóis/metabolismo , Caspase 3/efeitos dos fármacos , Caspase 9/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , China , Fase G2/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/patologia , Estresse Oxidativo/efeitos dos fármacos , Fosforilação , Proteínas Proto-Oncogênicas c-bcl-2/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/efeitos dos fármacos
13.
Nucleic Acids Res ; 45(7): 3738-3751, 2017 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-28062857

RESUMO

P-TEFb (CDK9/cyclin T) plays a central role in androgen receptor (AR)-mediated transactivation by phosphorylating both RNA polymerase 2 complex proteins and AR at S81. CDK9 dephosphorylation mobilizes P-TEFb from an inhibitory 7SK ribonucleoprotein complex, but mechanisms targeting phosphatases to P-TEFb are unclear. We show that AR recruits protein phosphatase 1α (PP1α), resulting in P-TEFb mobilization and CDK9-mediated AR S81 phosphorylation. This increased pS81 enhances p300 recruitment, histone acetylation, BRD4 binding and subsequent further recruitment of P-TEFb, generating a positive feedback loop that sustains transcription. AR S81 is also phosphorylated by CDK1, and blocking basal CDK1-mediated S81 phosphorylation markedly suppresses AR activity and initiation of this positive feedback loop. Finally, androgen-independent AR activity in castration-resistant prostate cancer (CRPC) cells is driven by increased CDK1-mediated S81 phosphorylation. Collectively these findings reveal a mechanism involving PP1α, CDK9 and CDK1 that is used by AR to initiate and sustain P-TEFb activity, which may be exploited to drive AR in CRPC.


Assuntos
Regulação Neoplásica da Expressão Gênica , Fator B de Elongação Transcricional Positiva/metabolismo , Neoplasias da Próstata/genética , Proteína Fosfatase 1/metabolismo , Receptores Androgênicos/metabolismo , Antagonistas de Receptores de Andrógenos/farmacologia , Proteína Quinase CDC2/metabolismo , Linhagem Celular Tumoral , Cromatina/metabolismo , Quinase 9 Dependente de Ciclina/metabolismo , Retroalimentação Fisiológica , Humanos , Masculino , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/metabolismo , Ativação Transcricional
14.
Proc Natl Acad Sci U S A ; 111(20): 7319-24, 2014 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-24778216

RESUMO

The androgen receptor (AR) is a key factor that regulates the behavior and fate of prostate cancer cells. The AR-regulated network is activated when AR binds enhancer elements and modulates specific enhancer-promoter looping. Kallikrein-related peptidase 3 (KLK3), which codes for prostate-specific antigen (PSA), is a well-known AR-regulated gene and its upstream enhancers produce bidirectional enhancer RNAs (eRNAs), termed KLK3e. Here, we demonstrate that KLK3e facilitates the spatial interaction of the KLK3 enhancer and the KLK2 promoter and enhances long-distance KLK2 transcriptional activation. KLK3e carries the core enhancer element derived from the androgen response element III (ARE III), which is required for the interaction of AR and Mediator 1 (Med1). Furthermore, we show that KLK3e processes RNA-dependent enhancer activity depending on the integrity of core enhancer elements. The transcription of KLK3e was detectable and its expression is significantly correlated with KLK3 (R(2) = 0.6213, P < 5 × 10(-11)) and KLK2 (R(2) = 0.5893, P < 5 × 10(-10)) in human prostate tissues. Interestingly, RNAi silencing of KLK3e resulted in a modest negative effect on prostate cancer cell proliferation. Accordingly, we report that an androgen-induced eRNA scaffolds the AR-associated protein complex that modulates chromosomal architecture and selectively enhances AR-dependent gene expression.


Assuntos
Elementos Facilitadores Genéticos , Regulação Neoplásica da Expressão Gênica , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/metabolismo , Animais , Células COS , Linhagem Celular Tumoral , Chlorocebus aethiops , Inativação Gênica , Humanos , Calicreínas/metabolismo , Masculino , Subunidade 1 do Complexo Mediador/metabolismo , Regiões Promotoras Genéticas , Próstata/metabolismo , Antígeno Prostático Específico/metabolismo , Interferência de RNA , Sequências Reguladoras de Ácido Nucleico , Calicreínas Teciduais/metabolismo , Transcrição Gênica , Ativação Transcricional
15.
Prostate ; 76(7): 649-61, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26847655

RESUMO

BACKGROUND: Previous reports have documented protein phosphatase 1 (PP1) as an essential androgen receptor (AR) activator. However, more systemic studies are needed to further define PP1 effects on AR, particularly in the settings of prostate cancer cells and under conditions mimicking androgen ablation. METHODS: PP1 effects on AR protein expression, degradation, ubiquitination, and stabilization were examined in non-prostate cancer cells, followed by validation on exogenous settings in androgen-sensitive (LNCaP and VCaP) and castration-resistant (C4-2) prostate cancer cells. Effects of PP1 on AR protein expression, on AR-mediated transcription of exogenous reporter and endogenous gene, and on LNCaP and C4-2 cell proliferation were monitored under androgen-containing versus androgen-depleted conditions to assess the effects of PP1 on AR responsiveness to androgen. RESULTS: In this report, we determined that PP1 functions to stabilize AR proteins that exclusively undergo the proteasome-dependent degradation, and the stimulatory effects of PP1 were predominantly mediated by the AR ligand-binding domain (LBD). Consistently, PP1 enhances AR protein stability by disrupting the LBD-mediated and K48-linked ubiquitination cascade. We further validated the above findings in the prostate cancer cells by showing that PP1 inhibition can increase ubiquitin- and proteasome-dependent degradation of endogenous AR under androgen deprivation. Significantly, we found that PP1 could markedly activate AR transcriptional activities under conditions mimicking androgen ablation and that androgen sensitivity was substantially evoked by PP1 inhibition in the prostate cancer cell lines. CONCLUSIONS: As summarized in a simplified model, our studies defined an essential PP1-mediated pathway for AR protein stabilization that can compensate the loss of androgen and established a mechanistic link between PP1 and androgen responsiveness. The amplified PP1-dependence for AR activation under the androgen ablated conditions provides a rationale to therapeutically target the PP1-AR module in the castration-resistant prostate cancer (CRPC). Our findings also suggested an alternative AR-targeting compounds screening strategy that aims to circumvent PP1-AR interaction.


Assuntos
Androgênios/metabolismo , Neoplasias da Próstata/metabolismo , Proteína Fosfatase 1/metabolismo , Receptores Androgênicos/metabolismo , Ativação Transcricional/genética , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/genética , Humanos , Masculino , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Receptores Androgênicos/genética
16.
Nanotechnology ; 27(33): 335704, 2016 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-27389929

RESUMO

We report the observation of the generation of dislocations in single-crystal phase-change In2Se3 nanowires under electrical pulses and the impact of these dislocations on electrical properties. Particularly, we correlated the atomic-scale structural characteristics with local electrical resistance variations, by performing transmission electron microscopy and scanning Kelvin probe microscopy on the same nanowires. By coupling the experimental results with first-principles density functional theory calculations, we show that the immobile dislocations are generated via vacancy condensations. Importantly, these dislocations lead to several orders of magnitude increase in the electrical resistance, while maintaining the single crystallinity of the lattice. These results significantly advance the fundamental understanding of the structure-property relation in this phase-change material under transient electrical excitations. From a practical perspective, the significant increase in the electrical resistance, driven by the formation of dislocations, can be exploited as a new electronic state in the single-crystalline phase in this phase-change material.

17.
Phys Chem Chem Phys ; 18(36): 24872-9, 2016 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-27545326

RESUMO

Exploration of the catalytic activity of low-dimensional transition metal (TM) or noble metal catalysts is a vital subject of modern materials science because of their instrumental role in numerous industrial applications. Recent experimental advances have demonstrated the utilization of single atoms on different substrates as effective catalysts, which exhibit amazing catalytic properties such as more efficient catalytic performance and higher selectivity in chemical reactions as compared to their nanostructured counterparts; however, the underlying microscopic mechanisms operative in these single atom catalysts still remain elusive. Based on first-principles calculations, herein, we present a comparative study of the key kinetic rate processes involved in CO oxidation using a monomer or dimer of two representative TMs (Pd and Ni) on defective TiO2(110) substrates (TMn@TiO2(110), n = 1, 2) to elucidate the underlying mechanism of single-atom catalysis. We reveal that the O2 activation rates of the single atom TM catalysts deposited on TiO2(110) are governed cooperatively by the classic spin-selection rule and the well-known frontier orbital theory (or generalized d-band picture) that emphasizes the energy gap between the frontier orbitals of the TM catalysts and O2 molecule. We further illuminate that the subsequent CO oxidation reactions proceed via the Langmuir-Hinshelwood mechanism with contrasting reaction barriers for the Pd monomer and dimer catalysts. These findings not only provide an explanation for existing observations of distinctly different catalytic activities of Pd@TiO2(110) and Pd2@TiO2(110) [Kaden et al., Science, 2009, 326, 826-829] but also shed new insights into future utilization and optimization of single-atom catalysis.

18.
Prep Biochem Biotechnol ; 46(4): 346-53, 2016 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-26030807

RESUMO

Foam fractionation and resin adsorption were used to recover soybean saponins from the industrial residue of soybean meal. First, a two-stage foam fractionation technology was studied for concentrating soybean saponins from the leaching liquor. Subsequently, resin adsorption was used to purify soybean saponins from the foamate in foam fractionation. The results showed that the enrichment ratio, the recovery percentage, and the purity of soybean saponins by using the two-stage foam fractionation technology could reach 4.45, 74%, and 67%, respectively. After resin adsorption and desorption, the purity of soybean saponins in the freeze-dried powder from the desorption solution was 88.4%.


Assuntos
Glycine max/química , Saponinas/isolamento & purificação , Adsorção , Concentração de Íons de Hidrogênio , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Acta Diabetol ; 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38954041

RESUMO

BACKGROUND: This study investigates the therapeutic mechanisms of Cai's Herbal Tea in Type 1 Diabetes Mellitus (T1DM) mice, focusing on its effects on mitochondrial change and autophagy via the AMP-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR) pathway. METHODS: The composition of Cai's Herbal Tea was analyzed by Ultra-High Performance Liquid Chromatography-Quadrupole Time of Flight Mass Spectrometry (UHPLC-Q/TOF-MS). C57BL/6 mice and Min6 pancreatic beta cells were divided into control, diabetic mellitus (DM)/high glucose (HG), and treatment groups (low, medium, and high doses of Cai's Tea, and Metformin). Key physiological parameters, pancreatic islet health, Min6 cell morphology, viability, and insulin (INS) secretion were assessed. Small Interfering RNA-AMPK (si-AMPK) was utilized to confirm the pathway involvement. RESULTS: Cai's Herbal Tea improved body weight, pancreatic islet pathological injury, and INS secretion whereas reduced total triglycerides, fasting blood sugar, and Interferon gamma (INF-γ) in T1DM mice, particularly at higher doses. In Min6 cells, Cai's Tea mitigated HG-induced damage and proinflammatory response, enhancing cell viability and INS secretion. Notably, it reduced swelling and improved cristae structure in treated groups of mitochondria and promoted autophagy via the AMPK-mTOR pathway, evidenced by increased LC3II/LC3I and P-AMPK/AMPK ratios, and decreased P-mTOR/mTOR and P62 expressions in pancreatic islet ß-cells. Furthermore, these effects were converted by si-AMPK interference. CONCLUSION: Cai's Herbal Tea exhibits significant therapeutic efficacy in T1DM mice by improving mitochondrial health and inducing autophagy through the AMPK-mTOR pathway in pancreatic islet ß-cells. These findings highlight its potential as a therapeutic approach for T1DM management.

20.
Int J Biol Macromol ; 254(Pt 2): 127886, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37926301

RESUMO

Dye pollution in the aquatic environment can harm ecosystems and human health. Here, we developed a new green adsorbent by applying an improved drying process. Diatomite was embedded in a network structure formed between chitosan and polyvinyl alcohol without using any crosslinking agent to prepare chitosan-polyvinyl alcohol-diatomite hydrogel beads through alkali solidification. The beads were tested for removing a cationic dye (methylene blue (MB)) from water. The structure of the adsorbent beads was analysed using scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The adsorption capacity was investigated, and the results indicated excellent MB adsorption properties. The adsorbents had a rough surface and high swelling capacity of 66.9 g/g. The maximum MB adsorption capacity was 414.70 mg/g, and the adsorption followed the Freundlich isothermal and quasi-second-order kinetic models. The adsorption was an endothermic spontaneous process governed by both intra-particle and external diffusion processes. The proposed adsorption mechanisms involved hydrogen bonding and electrostatic interactions. These adsorbent beads have considerable application potentials owing to their high adsorption capacity, green composition, and non-polluting nature.


Assuntos
Quitosana , Poluentes Químicos da Água , Purificação da Água , Humanos , Álcool de Polivinil , Azul de Metileno/química , Quitosana/química , Água/química , Ecossistema , Purificação da Água/métodos , Adsorção , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Hidrogéis , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA