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1.
Org Biomol Chem ; 2022 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-35695281

RESUMO

Herein, we report a Rh(III)-catalyzed C4-selective activation of indoles by using iodonium ylides as carbene precursors. This protocol proceeded under redox neutral reaction conditions and provided important coupling products with good tolerance of functional groups and high yields. In addition, one-pot synthesis and scale-up and mechanistic studies were also conducted.

2.
J Org Chem ; 86(23): 17063-17070, 2021 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-34797073

RESUMO

A tandem rhodium(III)-catalyzed system was established to access 3,4-dihydroisoquinolin-1(2H)-one by coupling of N-methoxy-3-methylbenzamide with 2-methylidenetrimethylene carbonate. This one-pot synthesis protocol processed smoothly under mild reaction conditions. Moreover, a total of 28 examples, broad substrate scope, and high functional-group compatibility were observed. Preliminary mechanism studies were also conducted and demonstrated that the rhodium(III) catalyst played a vital role in the C-H-allylation and N-alkylation cyclization process.


Assuntos
Ródio , Alquilação , Carbonatos , Catálise , Ciclização
3.
Hematol Oncol ; 2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34472655

RESUMO

This retrospective cohort study aimed to evaluate primary treatment and recent survival trends in patients with primary diffuse large B-cell lymphoma of central nervous system (CNS) from 1995 to 2016. Using the SEER data, patients diagnosed with non-HIV-associated primary central nervous system lymphoma (PCNSL)-diffuse large B-cell lymphoma (DLBCL) aged ⩾18 years between 1995 and 2016 were identified. The year of diagnosis was divided into the time period-1 (1995-2002), the time period-2 (2003-2012), and the time period-3 (2013-2016). Chi-square tests, the Kaplan-Meier method, log-rank test, and Cox regression model were used in the analysis. Overall, 3760 patients were included. Both the use of radiotherapy alone and the application of combined chemoradiotherapy decreased significantly, following the wider use of chemotherapy alone during 1995-2016. There was a significant improvement in PCNSL cause-specific survival (CSS) (period-1: 13 months vs. period-2: 19 months vs. period-3: 41 months, p < 0.001). Survival of patients aged above 70 years did not change from the time period-1 to the time period-2 (p = 0.101). However, there was an increase in CSS from the time period-2 to the time period-3 in the elderly patients (period-2: 5 months vs. period-3: 9 months, p < 0.001). On multivariable analyses, diagnosed in the time period-3 was significantly and independently associated with better CSS (hazard ratio 0.577, 95% confidence interval 0.506-0.659, p < 0.001). Our analysis shows the use of radiotherapy in the treatment of PCNSL has waned over the study span. There was a significant improvement in CSS during 1995-2016, which reflected developments in treatment over time. The elderly patient population also gained a significant CSS benefit in the most recent period.

4.
Org Lett ; 23(15): 5719-5723, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34286981

RESUMO

A rhodium(III)-catalyzed C-H allylation of (hetero)arenes by using 2-methylidenetrimethylene carbonate as an efficient allylic source has been developed for the first time. Five different directing groups including oxime, N-nitroso, purine, pyridine, and pyrimidine were compatible, delivering various branched allylarenes bearing an allylic hydroxyl group in moderate to excellent yields.

5.
Cell Rep ; 32(12): 108181, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32966797

RESUMO

Hemopexin (Hx) is a scavenger of labile heme. Herein, we present data defining the role of tumor stroma-expressed Hx in suppressing cancer progression. Labile heme and Hx levels are inversely correlated in the plasma of patients with prostate cancer (PCa). Further, low expression of Hx in PCa biopsies characterizes poorly differentiated tumors and correlates with earlier time to relapse. Significantly, heme promotes tumor growth and metastases in an orthotopic murine model of PCa, with the most aggressive phenotype detected in mice lacking Hx. Mechanistically, labile heme accumulates in the nucleus and modulates specific gene expression via interacting with guanine quadruplex (G4) DNA structures to promote PCa growth. We identify c-MYC as a heme:G4-regulated gene and a major player in heme-driven cancer progression. Collectively, these results reveal that sequestration of labile heme by Hx may block heme-driven tumor growth and metastases, suggesting a potential strategy to prevent and/or arrest cancer dissemination.


Assuntos
Heme/metabolismo , Hemopexina/metabolismo , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Ciclo Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Proliferação de Células , DNA/genética , Progressão da Doença , Quadruplex G , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Metástase Neoplásica , Fenótipo , Regiões Promotoras Genéticas/genética , Neoplasias da Próstata/sangue , Neoplasias da Próstata/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Resultado do Tratamento , Ativador de Plasminogênio Tipo Uroquinase/metabolismo
6.
Acta Pharmacol Sin ; 40(4): 522-529, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29921888

RESUMO

Silkworm cocoon was recorded to cure carbuncle in the Compendium of Materia Medica. Previous studies have demonstrated that the supplemental silk protein sericin exhibits anticancer activity. In the present study, we investigated the effects of silk fibroin peptide (SFP) extracted from silkworm cocoons against human lung cancer cells in vitro and in vivo and its possible anticancer mechanisms. SFP that we prepared had high content of glycine (~ 30%) and showed a molecular weight of ~ 10 kDa. Intragastric administration of SFP (30 g/kg/d) for 14 days did not affect the weights, vital signs, routine blood indices, and blood biochemical parameters in mice. MTT assay showed that SFP dose-dependently inhibited the growth of human lung cancer A549 and H460 cells in vitro with IC50 values of 9.921 and 9.083 mg/mL, respectively. SFP also dose-dependently suppressed the clonogenic activity of the two cell lines. In lung cancer H460 xenograft mice, intraperitoneal injection of SFP (200 or 500 mg/kg/d) for 40 days significantly suppressed the tumor growth, but did not induce significant changes in the body weight. We further examined the effects of SFP on cell cycle and apoptosis in H460 cells using flow cytometry, which revealed that SFP-induced cell cycle arrest at the S phase, and then promoted cell apoptosis. We demonstrated that SFP (20-50 mg/mL) dose-dependently downregulates Bcl-2 protein expression and upregulates Bax protein in H460 cells during cell apoptosis. The results suggest that SFP should be studied further as a novel therapeutic agent for the treatment of lung cancer.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Fibroínas/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Peptídeos/farmacologia , Células A549 , Animais , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Fibroínas/química , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Peptídeos/química , Relação Estrutura-Atividade
8.
PLoS One ; 8(11): e79573, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24260253

RESUMO

Taxane based chemotherapy is the standard of care treatment in castration resistant prostate cancer (CRPC). There is convincing evidence that taxane therapy affects androgen receptor (AR) but the exact mechanisms have to be further elucidated. Our studies identified c-jun as a crucial key player which interacts with AR and thus determines the outcome of the taxane therapy given. Docetaxel (Doc) and paclitaxel (Pac) agents showed different effects on LNCaP and LNb4 evidenced by alteration in the protein and mRNA levels of c-jun, AR and PSA. Docetaxel-induced phophorylation of c-jun occurred before JNK phosphorylation which suggests that c-jun phosphorylation is independent of JNK pathways in prostate cancer cells. A xenograft study showed that mice treated with Pac and bicalutamide showed worse outcome supporting our hypothesis that upregulation of c-jun might act as a potent antiapoptotic factor. We observed in our in vitro studies an inverse regulation of PSA- and AR-mRNA levels in Doc treated LNb4 cells. This was also seen for kallikrein 2 (KLK 2) which followed the same pattern. Given the fact that response to taxane therapy is measured by PSA decrease we have to consider that this might not reflect the true activity of AR in CRPC patients.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/farmacologia , Hidrocarbonetos Aromáticos com Pontes/uso terapêutico , Neoplasias da Próstata/tratamento farmacológico , Proteínas Proto-Oncogênicas c-jun/metabolismo , Receptores Androgênicos/metabolismo , Taxoides/farmacologia , Taxoides/uso terapêutico , Anilidas/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Nus , Nitrilas/uso terapêutico , Ligação Proteica , Proteínas Proto-Oncogênicas c-jun/genética , RNA Interferente Pequeno , Reação em Cadeia da Polimerase em Tempo Real , Receptores Androgênicos/genética , Compostos de Tosil/uso terapêutico
9.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(9): 2413-6, 2010 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-21105408

RESUMO

The optical characteristics of chromophoric dissolved organic matter (CDOM) were determined in rain samples collected in Xiamen Island, during a rainy season in 2007, using fluorescence excitation-emission matrix spectroscopy associated with UV-Vis absorbance spectra. Results showed that the absorbance spectra of CDOM in rain samples decreased exponentially with wavelength. The absorbance coefficient at 300 nm [a(300)] ranged from 0.27 to 3.45 m(-1), which would be used as an index of CDOM abundance, and the mean value was 1.08 m(-1). The content of earlier stage of precipitation events was higher than that of later stage of precipitation events, which implied that anthropogenic sources or atmospheric pollution or air mass types were important contributors to CDOM levels in precipitation. EEMs spectra showed 4 types of fluorescence signals (2 humic-like fluorescence peaks and 2 protein-like fluorescence peaks) in rainwater samples, and there were significant positive correlations of peak A with C and peak B with S, showing their same sources or some relationship of the two humic-like substance and the two protein-like substance. The strong positive correlations of the two humic-like fluorescence peaks with a(300), suggested that the chromophores responsible for absorbance might be the same as fluorophores responsible for fluorescence. Results showed that the presence of highly absorbing and fluorescing CDOM in rainwater is of significant importance in atmospheric chemistry and might play a previously unrecognized role in the wavelength dependent spectral attenuation of solar radiation by atmospheric waters.

10.
J Mol Endocrinol ; 41(1): 13-23, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18469090

RESUMO

Cellular changes that affect the androgen receptor (AR) can cause prostate cancer to transition from androgen dependent to androgen independent, which is usually lethal. One common change in prostate tumors is overexpression of the AR, which has been shown to lead to androgen-independent growth of prostate cancer cells. This led us to hypothesize that expression of a hyperactive AR would be sufficient for androgen-independent growth of prostate cancer cells. To test this hypothesis, stable lune cancer prostate (LNCaP) cell lines were generated, which express a virion phosphoprotein (VP)16-AR hybrid protein that contains full-length AR fused to the strong viral transcriptional activation domain VP16. This fusion protein elicited as much as a 20-fold stronger transcriptional activity than the natural AR. Stable expression of VP16-AR in LNCaP cells yielded androgen-independent cell proliferation, while under the same growth conditions the parental LNCaP cells exhibited only androgen-dependent growth. These results show that expression of a hyperactive AR is sufficient for androgen-independent growth of prostate cancer cells. To study the molecular basis of this enhanced growth, we measured the expression of soluble guanylyl cyclase-alpha1 (sGCalpha1), a subunit of the sGC, an androgen-regulated gene that has been shown to be involved in prostate cancer cell growth. Interestingly, the expression of sGCalpha1 is androgen independent in VP16-AR-expressing cells, in contrast to its androgen-induced expression in control LNCaP cells. RNA(I)-dependent inhibition of sGCalpha1 expression resulted in significantly reduced proliferation of VP16-AR cells, implicating an important role for sGCalpha1 in the androgen-independent growth of these cells.


Assuntos
Androgênios/fisiologia , Proliferação de Células , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Receptores Androgênicos/biossíntese , Receptores Androgênicos/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Masculino , Receptores Androgênicos/fisiologia , Transcrição Genética
11.
Huan Jing Ke Xue ; 28(8): 1788-95, 2007 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-17926412

RESUMO

Mussels have been proposed as appropriate biomonitors of marine pollution, especially for monitoring metallic pollution based on variations of metallothionein as biomarkers. Under 2 exposure levels (12.7 microg/L, 63.5 microg/L), Cu accumulation and metallothionein-like protein (MTLP) induction by mussel (Perna viridis) digestive glands were investigated and simulated into dynamic models in the present work, and the soluble and total Cu burden of digestive glands were also determined. Calculated mean Cu uptake rates by mussel target organ were 2.045 and 7.028 microg x (g x d)(-1) respectively, and the theoretical equilibrium kinetic BCFs of Cu were 2074 and 1619 correspondingly. And within the exposure duration, different changing trends of ratio of soluble Cu to total Cu in digestive glands were observed in the two groups. The MTLP level of control samples was (0.551 +/- 0.037) mg/g, and the counterparts are 0.407 - 0.699 mg/g, 0.826 - 0.942 mg/g respectively when mussels were exposed to 12.7 microg/L and 63.5 microg/L Cu solutions. Statistically significant MTLP induction (p < 0.001) was observed under higher exposure level. MTLP contents in digestive glands increased with the exposure Cu concentration and body accumulation of metal. There is a significantly negative exponential rise relationship (p < 0.000 1) between MTLP and Cu concentrations accumulated in the digestive glands of mussels.


Assuntos
Bivalves/metabolismo , Cobre/farmacocinética , Metalotioneína/metabolismo , Poluentes Químicos da Água/farmacocinética , Animais , Bivalves/efeitos dos fármacos , Cobre/metabolismo , Cobre/toxicidade , Sistema Digestório/efeitos dos fármacos , Sistema Digestório/metabolismo , Exposição Ambiental/análise , Distribuição Tecidual , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade
12.
Mol Endocrinol ; 21(8): 1835-46, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17505060

RESUMO

Androgens and the androgen receptor (AR) act in cells by modulating gene expression. Through gene microarray studies, we have identified Ets Variant Gene 1 (ETV1) as a novel androgen-regulated gene. Our data demonstrate that ETV1 mRNA and protein are up-regulated in response to ligand-activated AR in androgen-dependent LNCaP cells, but there is no detectable ETV1 expression in normal prostate cells. The ETV1 promoter is induced by androgens and recruits the AR in the context of chromatin. ETV1-regulated endogenous matrix metalloproteinase genes can be induced by ligand-activated AR. In contrast to the hormone-induced expression in androgen-dependent LNCaP cells, ETV1 expression in androgen-independent LNCaP cells is high and unresponsive to androgen. This androgen-independent ETV1 expression contrasts with the hormone-dependent expression observed for TMPRSS2 in these androgen-independent prostate cancer cells. ETV1 is overexpressed in prostate cancer independent of the TMPRSS2:ETV1 translocation. Disruption of ETV1 expression in both androgen-dependent and androgen-independent prostate cancer cells significantly compromises the invasion capacity of these cells, suggesting an important role for ETV1 in prostate cancer metastasis. Collectively, these results demonstrate that ETV1 expression transitions from androgen-induced to androgen-independent as prostate cancer cells switch from hormone-dependent to hormone-refractory and suggest that this transition may be in part responsible for the elevated levels of ETV1 observed in prostate tumors. Additionally, our data provide an indirect mechanism of AR regulation of gene expression, via the transactivation of the transcription factor ETV1.


Assuntos
Proteínas de Ligação a DNA/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Receptores Androgênicos/fisiologia , Fatores de Transcrição/genética , Androgênios/fisiologia , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/fisiologia , Di-Hidrotestosterona/metabolismo , Humanos , Masculino , Invasividade Neoplásica , Regiões Promotoras Genéticas , Neoplasias da Próstata/genética , Transdução de Sinais/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/fisiologia
13.
Cancer Res ; 66(15): 7783-92, 2006 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-16885382

RESUMO

Androgen receptor (AR) plays a central role in prostate cancer, with most tumors responding to androgen deprivation therapies, but the molecular basis for this androgen dependence has not been determined. Androgen [5alpha-dihydrotestosterone (DHT)] stimulation of LNCaP prostate cancer cells, which have constitutive phosphatidylinositol 3-kinase (PI3K)/Akt pathway activation due to PTEN loss, caused increased expression of cyclin D1, D2, and D3 proteins, retinoblastoma protein hyperphosphorylation, and cell cycle progression. However, cyclin D1 and D2 message levels were unchanged, indicating that the increases in cyclin D proteins were mediated by a post-transcriptional mechanism. This mechanism was identified as mammalian target of rapamycin (mTOR) activation. DHT treatment increased mTOR activity as assessed by phosphorylation of the downstream targets p70 S6 kinase and 4E-BP1, and mTOR inhibition with rapamycin blocked the DHT-stimulated increase in cyclin D proteins. Significantly, DHT stimulation of mTOR was not mediated through activation of the PI3K/Akt or mitogen-activated protein kinase/p90 ribosomal S6 kinase pathways and subsequent tuberous sclerosis complex 2/tuberin inactivation or by suppression of AMP-activated protein kinase. In contrast, mTOR activation by DHT was dependent on AR-stimulated mRNA synthesis. Oligonucleotide microarrays showed that DHT-stimulated rapid increases in multiple genes that regulate nutrient availability, including transporters for amino acids and other organic ions. These results indicate that a critical function of AR in PTEN-deficient prostate cancer cells is to support the pathologic activation of mTOR, possibly by increasing the expression of proteins that enhance nutrient availability and thereby prevent feedback inhibition of mTOR.


Assuntos
Ciclinas/biossíntese , Di-Hidrotestosterona/farmacologia , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Proteínas Quinases/metabolismo , Receptores Androgênicos/metabolismo , Proteínas Quinases Ativadas por AMP , Processos de Crescimento Celular/fisiologia , Linhagem Celular Tumoral , Ciclina D , Ativação Enzimática , Humanos , Masculino , Complexos Multienzimáticos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Neoplasias da Próstata/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Proteínas Quinases S6 Ribossômicas , Serina-Treonina Quinases TOR
14.
Endocrine ; 29(2): 363-73, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16785614

RESUMO

Through its transcriptional activities, the proto-oncoprotein c-Jun can regulate cellular proliferation, survival, and differentiation. We have established a novel yeast assay that screens for repressors of c-Jun transcriptional activity. This screen led to the identification of a ubiquitously expressed novel RING zinc finger protein, termed Makorin RING zinc finger protein 1 (MKRN1), recently shown to act as an E3 ubiquitin ligase. Overexpression of MKRN1 in mammalian cells inhibited the transcriptional activities of not only c-Jun, but also the nuclear receptors, the androgen receptor, and the retinoic acid receptors. Truncation analysis indicates that both the amino and carboxy termini are required for this transrepression activity. Surprisingly, when fused to the heterologous DNAbinding domain of GAL4, MKRN1 activates, rather than inhibits, a GAL4-responsive reporter plasmid. In addition, truncation of either the amino- or carboxy-terminal half of MKRN1 disrupts its transactivation activity, the same observation that was made on its transrepression activity. These results demonstrate that MKRN1 has transcriptional activity and suggest that its transrepression and transactivation functions are mediated by the same mechanism. Interestingly, disruption of MKRN1's ubiquitin ligase activity does not affect its inhibitory transcriptional activity. Thus, MKRN1 may represent a nuclear protein with multiple nuclear functions, including regulating RNA polymerase II-catalyzed transcription.


Assuntos
Proteínas do Tecido Nervoso/metabolismo , RNA Polimerase II/metabolismo , Ribonucleoproteínas/metabolismo , Transcrição Genética , Animais , Antígenos/metabolismo , Células COS , Chlorocebus aethiops , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo , Células HeLa , Humanos , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-jun/metabolismo , Receptores do Ácido Retinoico/antagonistas & inibidores , Saccharomyces cerevisiae/genética , Fator de Transcrição AP-1/antagonistas & inibidores , Técnicas do Sistema de Duplo-Híbrido , Ubiquitina-Proteína Ligases/metabolismo
15.
Mol Cell Biol ; 26(3): 929-39, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16428447

RESUMO

Androgen receptor (AR) interacts with beta-catenin and can suppress its coactivation of T cell factor 4 (Tcf4) in prostate cancer (PCa) cells. Pin1 is a peptidyl-prolyl cis/trans isomerase that stabilizes beta-catenin by inhibiting its binding to the adenomatous polyposis coli gene product and subsequent glycogen synthase kinase 3beta (GSK-3beta)-dependent degradation. Higher Pin1 expression in primary PCa is correlated with disease recurrence, and this study found that Pin1 expression was markedly increased in metastatic PCa. Consistent with this result, increased expression of Pin1 in transfected LNCaP PCa cells strongly accelerated tumor growth in vivo in immunodeficient mice. Pin1 expression in LNCaP cells enhanced beta-catenin/Tcf4 transcriptional activity, as assessed using Tcf4-regulated reporter genes, and increased expression of endogenous Tcf4 and c-myc. However, in contrast to results in cells with intact PTEN and active GSK-3beta, Pin1 expression in LNCaP PCa cells, which are PTEN deficient, did not increase beta-catenin. Instead, Pin1 expression markedly inhibited the beta-catenin interaction with AR, and Pin1 abrogated the ability of AR to antagonize beta-catenin/Tcf4 binding and transcriptional activity. These findings demonstrate that AR can suppress beta-catenin signaling, that the AR-beta-catenin interaction can be regulated by Pin1, and that abrogation of this interaction can enhance beta-catenin/Tcf4 signaling and contribute to aggressive biological behavior in PCa.


Assuntos
Antagonistas de Receptores de Andrógenos , Peptidilprolil Isomerase/metabolismo , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , beta Catenina/antagonistas & inibidores , Animais , Genes Reporter , Humanos , Luciferases/análise , Luciferases/genética , Masculino , Camundongos , Camundongos SCID , Mutação , Peptidilprolil Isomerase de Interação com NIMA , Metástase Neoplásica , PTEN Fosfo-Hidrolase/genética , Peptidilprolil Isomerase/genética , Estrutura Terciária de Proteína , Receptores Androgênicos/metabolismo , Transdução de Sinais , Fatores de Transcrição TCF/metabolismo , Proteína 2 Semelhante ao Fator 7 de Transcrição , Transcrição Genética , Transfecção , beta Catenina/metabolismo
16.
J Biol Chem ; 281(7): 4002-12, 2006 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-16361251

RESUMO

Androgens are important for male sexual development, which depend on the cognate receptor, the androgen receptor. The transcriptional activity of the androgen receptor, like other nuclear receptors, is regulated by accessory proteins that can have either positive or negative effects. Through a yeast functional screen, we have identified SUMO-3 as a regulator of androgen receptor activity in prostate cancer cells. SUMO-3 is one of three eukaryotic proteins that become post-translationally conjugated to their target proteins in a manner analogous to the attachment of ubiquitin. In primary prostate epithelial cells, PrEC, and the prostate cancer cells, PC-3, SUMO-3 has a weak negative effect on androgen receptor transcriptional activity. In contrast, SUMO-3 and it close relative SUMO-2 strongly enhance transactivation by endogenous androgen receptor in LNCaP cells. This positive effect is observed in both androgen-dependent and androgen-independent LNCaP cells. Interestingly, SUMO-1, unlike SUMO-3 and SUMO-2, can inhibit, but not stimulate, androgen receptor activity. Mutational analysis of the androgen receptor and SUMO-3 demonstrates that the SUMO-3-positive activity does not depend on either the sumoylation sites of the androgen receptor or the sumoylation function of SUMO-3. Stable overexpression of SUMO-3 in LNCaP cells significantly enhances the androgen-dependent proliferation of these cells. Additionally, siRNA-mediated repression of SUMO-2 significantly inhibits the growth of both androgen-dependent and -independent LNCaP cells. Collectively, these results suggest (i) a novel mechanism for elevating AR activity through the switch of SUMO-3 from a weak negative regulator in normal prostate cells to a strong positive regulator in prostate cancer cells and (ii) a proliferative role for SUMO-3 and SUMO-2 in the growth of prostate cancer cells that is independent of sumoylation of the androgen receptor.


Assuntos
Neoplasias da Próstata/metabolismo , Receptores Androgênicos/fisiologia , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/fisiologia , Ativação Transcricional , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Masculino , Coativador 2 de Receptor Nuclear/fisiologia , Regiões Promotoras Genéticas , Neoplasias da Próstata/etiologia , Neoplasias da Próstata/patologia , Processamento de Proteína Pós-Traducional , Proteínas Proto-Oncogênicas c-jun/fisiologia , RNA Mensageiro/análise , RNA Interferente Pequeno/farmacologia , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética
17.
Mol Endocrinol ; 18(10): 2388-401, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15256534

RESUMO

Prostate cancers respond to treatments that suppress androgen receptor (AR) function, with bicalutamide, flutamide, and cyproterone acetate (CPA) being AR antagonists in clinical use. As CPA has substantial agonist activity, it was examined to identify AR coactivator/corepressor interactions that may mediate androgen-stimulated prostate cancer growth. The CPA-liganded AR was coactivated by steroid receptor coactivator-1 (SRC-1) but did not mediate N-C terminal interactions or recruit beta-catenin, indicating a nonagonist conformation. Nonetheless, CPA did not enhance AR interaction with nuclear receptor corepressor, whereas the AR antagonist RU486 (mifepristone) strongly stimulated AR-nuclear receptor corepressor binding. The role of coactivators was further assessed with a T877A AR mutation, found in LNCaP prostate cancer cells, which converts hydroxyflutamide (HF, the active flutamide metabolite) into an agonist that stimulates LNCaP cell growth. The HF and CPA-liganded T877A ARs were coactivated by SRC-1, but only the HF-liganded T877A AR was coactivated by beta-catenin. L-39, a novel AR antagonist that transcriptionally activates the T877A AR, but still inhibits LNCaP growth, similarly mediated recruitment of SRC-1 and not beta-catenin. In contrast, beta-catenin coactivated a bicalutamide-responsive mutant AR (W741C) isolated from a bicalutamide-stimulated LNCaP subline, further implicating beta-catenin recruitment in AR-stimulated growth. Androgen-stimulated prostate-specific antigen gene expression in LNCaP cells could be modulated by beta-catenin, and endogenous c-myc expression was repressed by dihydrotestosterone, but not CPA. These results indicate that interactions between AR and beta-catenin contribute to prostate cell growth in vivo, although specific growth promoting genes positively regulated by AR recruitment of beta-catenin remain to be identified.


Assuntos
Proteínas do Citoesqueleto/fisiologia , Neoplasias da Próstata/patologia , Receptores Androgênicos/fisiologia , Transativadores/fisiologia , Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proteínas do Citoesqueleto/genética , Di-Hidrotestosterona/farmacologia , Humanos , Masculino , Reação em Cadeia da Polimerase/métodos , RNA Interferente Pequeno/genética , Receptores Androgênicos/genética , Transativadores/genética , Transfecção , beta Catenina
18.
J Biol Chem ; 279(18): 19191-200, 2004 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-14985354

RESUMO

Kinases can phosphorylate and regulate androgen receptor activity during prostate cancer progression. In particular, we showed that glycogen synthase kinase-3 beta phosphorylates the androgen receptor, thereby inhibiting androgen receptor-driven transcription. Conversely, the glycogen synthase kinase-3 beta inhibitor lithium chloride suppressed the glycogen synthase kinase-3 beta-mediated phosphorylation of the androgen receptor, thereby enabling androgen receptor-driven transcription to occur. The androgen receptor hinge and ligand-binding domains were important for both the phosphorylation and the inhibition of transcriptional activity of the receptor by glycogen synthase kinase-3 beta. Furthermore, androgen receptor phosphorylation was augmented by LY294002, an indirect inhibitor of protein kinase B/Akt that inhibits glycogen synthase kinase-3 beta. We also showed that the mutation of various phosphorylation sites on glycogen synthase kinase-3 beta affected the ability of these mutants to co-distribute with the androgen receptor in the cell nucleus, also that both glycogen synthase kinase-3beta and androgen receptor proteins can be found in cell nuclei of prostate cancer tissue samples. Because glycogen synthase kinase-3 beta activity is suppressed after the enzyme is phosphorylated by protein kinase B/Akt and Akt activity frequently increases during the progression of prostate cancer, nullification of the glycogen synthase kinase-3 beta-mediated suppression of androgen receptor activity by Akt likely contributes to prostate cancer progression.


Assuntos
Antagonistas de Receptores de Andrógenos , Regulação Neoplásica da Expressão Gênica , Quinase 3 da Glicogênio Sintase/fisiologia , Neoplasias da Próstata/patologia , Compartimento Celular , Linhagem Celular Tumoral , Variação Genética , Quinase 3 da Glicogênio Sintase/genética , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Humanos , Masculino , Fosforilação , Estrutura Terciária de Proteína , Receptores Androgênicos/metabolismo , Receptores Androgênicos/fisiologia , Transcrição Genética , Transfecção
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