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1.
Commun Biol ; 4(1): 1019, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34465850

RESUMO

Despite the uniform mortality in pancreatic adenocarcinoma (PDAC), clinical disease heterogeneity exists with limited genomic differences. A highly aggressive tumor subtype termed 'basal-like' was identified to show worse outcomes and higher inflammatory responses. Here, we focus on the microbial effect in PDAC progression and present a comprehensive analysis of the tumor microbiome in different PDAC subtypes with resectable tumors using metagenomic sequencing. We found distinctive microbial communities in basal-like tumors and identified an increasing abundance of Acinetobacter, Pseudomonas and Sphingopyxis to be highly associated with carcinogenesis. Functional characterization of microbial genes suggested the potential to induce pathogen-related inflammation. Host-microbiota interplay analysis provided new insights into the tumorigenic role of specific microbiome compositions and demonstrated the influence of host genetics in shaping the tumor microbiome. Taken together, these findings indicated that the tumor microbiome is closely related to PDAC oncogenesis and the induction of inflammation. Additionally, our data revealed the microbial basis of PDAC heterogeneity and proved the predictive value of the microbiome, which will contribute to the intervention and treatment of disease.

2.
Cell Death Dis ; 11(9): 812, 2020 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-32980867

RESUMO

BRCA2 is crucial for repairing DNA double-strand breaks with high fidelity, and loss of BRCA2 increases the risks of developing breast and ovarian cancers. Herein, we show that BRCA2 is inactively mutated in 10% of gastric and 7% of colorectal adenocarcinomas, and that this inactivation is significantly correlated with microsatellite instability. Villin-driven Brca2 depletion promotes mouse gastrointestinal tumor formation when genome instability is increased. Whole-genome screening data showed that these BRCA2 monoallelic and biallelic mutant tumors were selectively inhibited by mitomycin C. Mechanistically, mitomycin C provoked double-strand breaks in cancer cells that often recruit wild-type BRCA2 for repair; the failure to repair double-strand breaks caused cell-cycle arrest at the S phase and p53-mediated cell apoptosis of BRCA2 monoallelic and biallelic mutant tumor cells. Our study unveils the role of BRCA2 loss in the development of gastrointestinal tumors and provides a potential therapeutic strategy to eliminate BRCA2 monoallelic and biallelic mutant tumors through mitomycin C.


Assuntos
Proteína BRCA2/deficiência , Neoplasias Gastrointestinais/genética , Mitomicina/metabolismo , Animais , Humanos , Camundongos
3.
EBioMedicine ; 48: 289-300, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31648989

RESUMO

BACKGROUND: Thymidylate synthase (TYMS) is a successful chemotherapeutic target for anticancer therapy. Numerous TYMS inhibitors have been developed and used for treating gastrointestinal cancer now, but they have limited clinical benefits due to the prevalent unresponsiveness and toxicity. It is urgent to identify a predictive biomarker to guide the precise clinical use of TYMS inhibitors. METHODS: Genome-scale CRISPR-Cas9 knockout screening was performed to identify potential therapeutic targets for treating gastrointestinal tumours as well as key regulators of raltitrexed (RTX) sensitivity. Cell-based functional assays were used to investigate how MYC regulates TYMS transcription. Cancer patient data were used to verify the correlation between drug response and MYC and/or TYMS mRNA levels. Finally, the role of NIPBL inactivation in gastrointestinal cancer was evaluated in vitro and in vivo. FINDINGS: TYMS is essential for maintaining the viability of gastrointestinal cancer cells, and is selectively inhibited by RTX. Mechanistically, MYC presets gastrointestinal cancer sensitivity to RTX through upregulating TYMS transcription, supported by TCGA data showing that complete response cases to TYMS inhibitors had significantly higher MYC and TYMS mRNA levels than those of progressive diseases. NIPBL inactivation decreases the therapeutic responses of gastrointestinal cancer to RTX through blocking MYC. INTERPRETATION: Our study unveils a mechanism of how TYMS is transcriptionally regulated by MYC, and provides rationales for the precise use of TYMS inhibitors in the clinic. FUNDING: This work was financially supported by grants of NKRDP (2016YFC1302400), STCSM (16JC1406200), NSFC (81872890, 81322034, 81372346) and CAS (QYZDB-SSW-SMC034, XDA12020210).


Assuntos
Resistência a Medicamentos/genética , Antagonistas do Ácido Fólico/farmacologia , Neoplasias Gastrointestinais/genética , Regulação Neoplásica da Expressão Gênica , Genes myc , Timidilato Sintase/genética , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Neoplasias Gastrointestinais/metabolismo , Humanos , Timidilato Sintase/antagonistas & inibidores , Timidilato Sintase/metabolismo , Transcrição Genética
4.
Stem Cells ; 34(6): 1527-40, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26866517

RESUMO

Histone demethylases have emerged as key regulators of biological processes. The H3K9me2 demethylase plant homeo domain finger protein 8(PHF8), for example, is involved in neuronal differentiation, but its potential function in the differentiation of embryonic stem cells (ESCs) to cardiomyocytes is poorly understood. Here, we explored the role of PHF8 during mesodermal and cardiac lineage commitment of mouse ESCs (mESCs). Using a phf8 knockout (ph8(-/Y) ) model, we found that deletion of phf8 in ESCs did not affect self-renewal, proliferation or early ectodermal/endodermal differentiation, but it did promote the mesodermal lineage commitment with the enhanced cardiomyocyte differentiation. The effects were accompanied by a reduction in apoptosis through a caspase 3-independent pathway during early ESC differentiation, without significant differences between differentiating wide-type (ph8(+/Y) ) and ph8(-/Y) ESCs in cell cycle progression or proliferation. Functionally, PHF8 promoted the loss of a repressive mark H3K9me2 from the transcription start site of a proapoptotic gene pmaip1 and activated its transcription. Furthermore, knockdown of pmaip1 mimicked the phenotype of ph8(-/Y) by showing the decreased apoptosis during early differentiation of ESCs and promoted mesodermal and cardiac commitment, while overexpression of pmaip1 or phf8 rescued the phenotype of ph8(-/Y) ESCs by increasing the apoptosis and weakening the mesodermal and cardiac differentiation. These results reveal that the histone demethylase PHF8 regulates mesodermal lineage and cell fate decisions in differentiating mESCs through epigenetic control of the gene critical to programmed cell death pathways. Stem Cells 2016;34:1527-1540.


Assuntos
Diferenciação Celular , Desmetilação , Histona Desmetilases/metabolismo , Histonas/metabolismo , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Miócitos Cardíacos/citologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Fatores de Transcrição/metabolismo , Animais , Apoptose , Linhagem da Célula , Proliferação de Células , Sobrevivência Celular , Deleção de Genes , Técnicas de Silenciamento de Genes , Humanos , Mesoderma/citologia , Camundongos , Modelos Biológicos , Miócitos Cardíacos/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo
5.
J Genet Genomics ; 42(8): 423-36, 2015 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-26336799

RESUMO

Although there is an accumulating appreciation of the key roles that long intergenic non-coding RNAs (lincRNAs) play in diverse cellular processes, our knowledge of how lincRNAs function in cancer remains sparse. Here, we present a comprehensive landscape of RNA-seq transcriptome profiles of lung adenocarcinomas and their paired normal counterparts to unravel gene regulation rules of lincRNAs. Consistent with previous findings of co-expression between neighboring protein-coding genes, lincRNAs were typically co-expressed with their neighboring genes, which was found in both cancerous and normal tissues. By building a mathematical model based on correlated gene expression, we distinguished an additional subset of lincRNAs termed "regulatory lincRNAs", representing their dominant roles in gene regulation. The number of regulatory lincRNAs was significantly higher in cancerous compared to normal tissues, and most of them positively regulated protein-coding genes in trans. Functional validation, using knockdown, determined that regulatory lincRNA, GAS5, affected its predicted protein-coding targets. Moreover, we discovered hundreds of differentially expressed regulatory lincRNAs with inclusion of some cancer-associated lincRNAs. Our integrated analysis reveals enhanced regulatory effects of lincRNAs and provides a resource for the study of regulatory lincRNAs that play critical roles in lung adenocarcinoma.


Assuntos
Adenocarcinoma/metabolismo , Regulação da Expressão Gênica , Neoplasias Pulmonares/metabolismo , RNA Longo não Codificante/metabolismo , Análise de Sequência de RNA , Adenocarcinoma de Pulmão , Biomarcadores Tumorais/metabolismo , Humanos , Modelos Teóricos , RNA Longo não Codificante/química , RNA Nucleolar Pequeno/metabolismo , Transcriptoma
6.
Am J Transl Res ; 7(6): 1009-20, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26279746

RESUMO

Triple-negative breast cancer (TNBC), which is closely related to basal-like breast cancer, is a highly aggressive subtype of breast cancer that initially responds to chemotherapy but eventually develops resistance. This presents a major clinical challenge as there are currently no effective targeted therapies available due to its lack of HER2 and estrogen receptor expression. Here, we show that cyclin E and the enhancer of zeste 2 (EZH2) are closely co-expressed in TNBC patients, and cyclin E/CDK2 phosphorylates EZH2 at T416 (pT416-EZH2) in vivo. Phosphorylation of EZH2 at T416 enhances the ability of EZH2 to promote TNBC cell migration/invasion, tumorsphere formation, and in vivo tumor growth. In addition, high pT416-EZH2 correlates with poorer survival in TNBC patients. These findings suggest that pT416 has the potential to serve as a therapeutic biomarker for the aggressive forms of breast cancer and provide a rationale for the use of CDK2 inhibitors to treat TNBC.

7.
Am J Transl Res ; 6(6): 649-63, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25628777

RESUMO

Nuclear translocation of EGFR has been shown to be important for tumor cell growth, survival, and therapeutic resistance. Previously, we detected the association of EGFR with Keap1 in the nucleus. Keap1 is a Kelch-like ECH-associated protein, which plays an important role in cellular response to chemical and oxidative stress by regulating Nrf2 protein stability and nuclear translocation. In this study, we investigate the role of EGFR in regulating Keap1/Nrf2 cascade in the nucleus and provide evidence to show that nuclear EGFR interacts with and phosphorylates nuclear Keap1 to reduce its nuclear protein level. The reduction of nuclear Keap1 consequently stabilizes nuclear Nrf2 and increases its transcriptional activity in cancer cells, which contributes to tumor cell resistance to chemotherapy.

8.
Cancer Cell ; 23(6): 796-810, 2013 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-23764002

RESUMO

Epidermal growth factor receptor (EGFR) initiates a signaling cascade that leads to DNA synthesis and cell proliferation, but its role in regulating DNA replication licensing is unclear. Here, we show that activated EGFR phosphorylates the p56 isoform of Lyn, p56(Lyn), at Y32, which then phosphorylates MCM7, a licensing factor critical for DNA replication, at Y600 to increase its association with other minichromosome maintenance complex proteins, thereby promoting DNA synthesis complex assembly and cell proliferation. Both p56(Lyn) Y32 and MCM7 Y600 phosphorylation are enhanced in proliferating cells and correlated with poor survival of breast cancer patients. These results establish a signaling cascade in which EGFR enhances MCM7 phosphorylation and DNA replication through Lyn phosphorylation in human cancer cells.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas de Ciclo Celular/fisiologia , Replicação do DNA/fisiologia , Proteínas de Ligação a DNA/fisiologia , Receptores ErbB/fisiologia , Proteínas Nucleares/fisiologia , Quinases da Família src/metabolismo , Animais , Neoplasias da Mama/patologia , Proteínas de Ciclo Celular/metabolismo , Proliferação de Células , Proteínas de Ligação a DNA/metabolismo , Receptores ErbB/genética , Receptores ErbB/metabolismo , Feminino , Humanos , Camundongos , Componente 7 do Complexo de Manutenção de Minicromossomo , Proteínas Nucleares/metabolismo , Fosforilação , Prognóstico , Transdução de Sinais , Tirosina/química , Tirosina/metabolismo , Quinases da Família src/fisiologia
9.
Cancer Cell ; 21(3): 374-87, 2012 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-22439934

RESUMO

Esophageal adenocarcinoma (EAC) is the most prevalent esophageal cancer type in the United States. The TNF-α/mTOR pathway is known to mediate the development of EAC. Additionally, aberrant activation of Gli1, downstream effector of the Hedgehog (HH) pathway, has been observed in EAC. In this study, we found that an activated mTOR/S6K1 pathway promotes Gli1 transcriptional activity and oncogenic function through S6K1-mediated Gli1 phosphorylation at Ser84, which releases Gli1 from its endogenous inhibitor, SuFu. Moreover, elimination of S6K1 activation by an mTOR pathway inhibitor enhances the killing effects of the HH pathway inhibitor. Together, our results established a crosstalk between the mTOR/S6K1 and HH pathways, which provides a mechanism for SMO-independent Gli1 activation and also a rationale for combination therapy for EAC.


Assuntos
Adenocarcinoma/metabolismo , Neoplasias Esofágicas/metabolismo , Proteínas Hedgehog/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/fisiologia , Transdução de Sinais , Serina-Treonina Quinases TOR/fisiologia , Adenocarcinoma/genética , Animais , Proliferação de Células , Neoplasias Esofágicas/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas Hedgehog/genética , Proteínas Hedgehog/fisiologia , Humanos , Modelos Biológicos , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Proteínas Repressoras/fisiologia , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/fisiologia , Proteína GLI1 em Dedos de Zinco
10.
J Clin Invest ; 121(11): 4526-36, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21985787

RESUMO

Colorectal cancer is the second leading cause of death from cancer in the United States. Metastases in the liver, the most common metastatic site for colorectal cancer, are found in one-third of the patients who die of colorectal cancer. Currently, the genes and molecular mechanisms that are functionally critical in modulating colorectal cancer hepatic metastasis remain unclear. Here, we report our studies using functional selection in an orthotopic mouse model of colorectal cancer to identify a set of genes that play an important role in mediating colorectal cancer liver metastasis. These genes included APOBEC3G, CD133, LIPC, and S100P. Clinically, we found these genes to be highly expressed in a cohort of human hepatic metastasis and their primary colorectal tumors, suggesting that it might be possible to use these genes to predict the likelihood of hepatic metastasis. We have further revealed what we believe to be a novel mechanism in which APOBEC3G promotes colorectal cancer hepatic metastasis through inhibition of miR-29-mediated suppression of MMP2. Together, our data elucidate key factors and mechanisms involved in colorectal cancer liver metastasis, which could be potential targets for diagnosis and treatment.


Assuntos
Neoplasias Colorretais/fisiopatologia , Citidina Desaminase/fisiologia , Neoplasias Hepáticas Experimentais/secundário , Desaminase APOBEC-3G , Animais , Sequência de Bases , Linhagem Celular Tumoral , Neoplasias Colorretais/genética , Citidina Desaminase/genética , Perfilação da Expressão Gênica , Humanos , Neoplasias Hepáticas Experimentais/genética , Neoplasias Hepáticas Experimentais/fisiopatologia , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 2 da Matriz/metabolismo , Camundongos , Camundongos Nus , MicroRNAs/genética , MicroRNAs/metabolismo , Transplante de Neoplasias , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transplante Heterólogo
11.
Cancer Cell ; 20(3): 341-56, 2011 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-21907925

RESUMO

Breast cancer initiating cells (BCICs), which can fully recapitulate the tumor origin and are often resistant to chemo- and radiotherapy, are currently considered as a major obstacle for breast cancer treatment. Here, we show that BIKDD, a constitutively active mutant form of proapoptotic gene, BIK, effectively induces apoptosis of breast cancer cells and synergizes with lapatinib. Most importantly, BikDD significantly reduces BCICs through co-antagonism of its binding partners Bcl-2, Bcl-xL, and Mcl-1, suggesting a potential therapeutic strategy targeting BCICs. Furthermore, we developed a cancer-specific targeting approach for breast cancer that selectively expresses BikDD in breast cancer cells including BCICs, and demonstrated its potent antitumor activity and synergism with lapatinib in vitro and in vivo.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Neoplasias da Mama , Proteínas de Membrana/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Quinazolinas/uso terapêutico , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas Reguladoras de Apoptose/biossíntese , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Antígeno CD24/biossíntese , Linhagem Celular Tumoral , Claudina-4 , Feminino , Humanos , Receptores de Hialuronatos/biossíntese , Lapatinib , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Mitocondriais , Proteína de Sequência 1 de Leucemia de Células Mieloides , Paclitaxel/farmacologia , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Quinazolinas/administração & dosagem , Quinazolinas/farmacologia , Proteína bcl-X/antagonistas & inibidores
12.
J Biol Chem ; 286(33): 29127-29138, 2011 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-21676868

RESUMO

Up-regulation of the dolichol pathway, a "hallmark" of asparagine-linked protein glycosylation, enhances angiogenesis in vitro. The dynamic relationship between these two processes is now evaluated with tunicamycin. Capillary endothelial cells treated with tunicamycin were growth inhibited and could not be reversed with exogenous VEGF(165). Inhibition of angiogenesis is supported by down-regulation of (i) phosphorylated VEGFR1 and VEGFR2 receptors; (ii) VEGF(165)-specific phosphotyrosine kinase activity; and (iii) Matrigel(TM) invasion and chemotaxis. In vivo, tunicamycin prevented the vessel development in Matrigel(TM) implants in athymic Balb/c (nu/nu) mice. Immunohistochemical analysis of CD34 (p < 0.001) and CD144 (p < 0.001) exhibited reduced vascularization. A 3.8-fold increased expression of TSP-1, an endogenous angiogenesis inhibitor in Matrigel(TM) implants correlated with that in tunicamycin (32 h)-treated capillary endothelial cells. Intravenous injection of tunicamycin (0.5 mg/kg to 1.0 mg/kg) per week slowed down a double negative (MDA-MB-435) grade III breast adenocarcinoma growth by ∼50-60% in 3 weeks. Histopathological analysis of the paraffin sections indicated significant reduction in vessel size, the microvascular density and tumor mitotic index. Ki-67 and VEGF expression in tumor tissue were also reduced. A significant reduction of N-glycan expression in tumor microvessel was also observed. High expression of GRP-78 in CD144-positive cells supported unfolded protein response-mediated ER stress in tumor microvasculature. ∼65% reduction of a triple negative (MDA-MB-231) breast tumor xenograft in 1 week with tunicamycin (0.25 mg/kg) given orally and the absence of systemic and/or organ failure strongly supported tunicamycin's potential for a powerful glycotherapeutic treatment of breast cancer in the clinic.


Assuntos
Antivirais/farmacologia , Neoplasias da Mama/tratamento farmacológico , Neovascularização Patológica/tratamento farmacológico , Tunicamicina/farmacologia , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Animais , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Transplante de Neoplasias , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Trombospondina 1/biossíntese , Transplante Heterólogo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
13.
Cancer Res ; 71(6): 2183-92, 2011 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-21406399

RESUMO

EGF activates NF-κB, and constitutively activated NF-κB contributes to EGFR mutation-associated tumorigenesis, but it remains unclear precisely how EGFR signaling leads to NF-κB activation. Here we report that CARMA3, a caspase recruitment domain (CARD)-containing scaffold molecule, is required for EGF-induced NF-κB activation. CARMA3 deficiency impaired the activation of the IKK complex following EGF stimulation, resulting in a defect of EGF-induced IκBα phosphorylation and NF-κB activation. We found that CARMA3 and Bcl10 contributed to several characteristics of EGFR-associated malignancy, including proliferation, survival, migration, and invasion. Most importantly, CARMA3 contributed to tumor growth in vivo. Our findings elucidate a crucial link between EGFR-proximal signaling components and the downstream IKK complex, and they suggest a new therapeutic target for treatment of EGFR-driven cancers.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Receptores ErbB/metabolismo , NF-kappa B/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteína 10 de Linfoma CCL de Células B , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Proteínas Adaptadoras de Sinalização CARD/genética , Ciclo Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Sobrevivência Celular , Fator de Crescimento Epidérmico/farmacologia , Receptores ErbB/genética , Feminino , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Proteínas I-kappa B/metabolismo , Masculino , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Nus , Inibidor de NF-kappaB alfa , Interferência de RNA , Transplante Heterólogo , Carga Tumoral
14.
Nat Cell Biol ; 13(1): 87-94, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21131960

RESUMO

Enhancer of zeste homologue 2 (EZH2) is the catalytic subunit of Polycomb repressive complex 2 (PRC2) and catalyses the trimethylation of histone H3 on Lys 27 (H3K27), which represses gene transcription. EZH2 enhances cancer-cell invasiveness and regulates stem cell differentiation. Here, we demonstrate that EZH2 can be phosphorylated at Thr 487 through activation of cyclin-dependent kinase 1 (CDK1). The phosphorylation of EZH2 at Thr 487 disrupted EZH2 binding with the other PRC2 components SUZ12 and EED, and thereby inhibited EZH2 methyltransferase activity, resulting in inhibition of cancer-cell invasion. In human mesenchymal stem cells, activation of CDK1 promoted mesenchymal stem cell differentiation into osteoblasts through phosphorylation of EZH2 at Thr 487. These findings define a signalling link between CDK1 and EZH2 that may have an important role in diverse biological processes, including cancer-cell invasion and osteogenic differentiation of mesenchymal stem cells.


Assuntos
Proteína Quinase CDC2/metabolismo , Diferenciação Celular , Proteínas de Ligação a DNA/metabolismo , Histonas/metabolismo , Células-Tronco Mesenquimais/metabolismo , Fatores de Transcrição/metabolismo , 2-Aminopurina/análogos & derivados , 2-Aminopurina/farmacologia , Proteína Quinase CDC2/antagonistas & inibidores , Proteína Quinase CDC2/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Movimento Celular , Proteínas de Ligação a DNA/genética , Proteína Potenciadora do Homólogo 2 de Zeste , Células HEK293 , Células HeLa , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Immunoblotting , Lisina/metabolismo , Células-Tronco Mesenquimais/citologia , Metilação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Osteoblastos/citologia , Osteoblastos/metabolismo , Fosforilação , Complexo Repressor Polycomb 2 , Ligação Proteica , Interferência de RNA , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Treonina/metabolismo , Fatores de Transcrição/genética
15.
Biochem Biophys Res Commun ; 404(1): 68-73, 2011 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-21094134

RESUMO

Alteration of epidermal growth factor receptor (EGFR) is involved in various human cancers and has been intensively investigated. A plethora of evidence demonstrates that posttranslational modifications of EGFR play a pivotal role in controlling its function and metabolism. Here, we show that EGFR can be acetylated by CREB binding protein (CBP) acetyltransferase. Interestingly, EGFR acetylation affects its tyrosine phosphorylation, which may contribute to cancer cell resistance to histone deacetylase inhibitors (HDACIs). Since there is an increasing interest in using HDACIs to treat various cancers in the clinic, our current study provides insights and rationale for selecting effective therapeutic regimen. Consistent with the previous reports, we also show that HDACI combined with EGFR inhibitors achieves better therapeutic outcomes and provides a molecular rationale for the enhanced effect of combination therapy. Our results unveil a critical role of EGFR acetylation that regulates EGFR function, which may have an important clinical implication.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/enzimologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Resistencia a Medicamentos Antineoplásicos , Receptores ErbB/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Acetilação/efeitos dos fármacos , Animais , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular Tumoral , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Feminino , Inibidores de Histona Desacetilases/uso terapêutico , Humanos , Ácidos Hidroxâmicos/farmacologia , Ácidos Hidroxâmicos/uso terapêutico , Lisina/genética , Lisina/metabolismo , Camundongos , Camundongos Endogâmicos , RNA Interferente Pequeno/genética , Vorinostat
16.
Cancer Res ; 70(19): 7684-9, 2010 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-20841468

RESUMO

Amplification or overexpression of murine double minute 2 (MDM2) promotes a variety of human tumors by degrading tumor suppressor proteins such as p53. Phosphorylation of MDM2 on Ser(166) and Ser(186) by the survival kinase Akt inhibits p53-mediated apoptosis. However, it is unclear whether this pathway contributes to normal or malignant pathophysiology in vivo. To address these questions, we generated transgenic mice expressing the Akt-phosphorylated form of MDM2 (MDM2DDS166D/S186D) in the mammary epithelium. Activation of MDM2 delayed mammary gland involution and accelerated tumor progression in mouse mammary tumor virus/neu transgenic mice by inhibiting apoptosis in a manner associated with decreased p53 expression. Our findings offer in vivo evidence that activation of MDM2 by Akt contributes to mammary development and tumorigenesis.


Assuntos
Glândulas Mamárias Animais/metabolismo , Neoplasias Mamárias Experimentais/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Animais , Apoptose/fisiologia , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Células Epiteliais/patologia , Glândulas Mamárias Animais/patologia , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Transgênicos , Proteína Supressora de Tumor p53/metabolismo
17.
J Nat Prod ; 73(9): 1553-8, 2010 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-20738103

RESUMO

A new quassinoid, designated 2'-(R)-O-acetylglaucarubinone (1), and seven known quassinoids (2-8) were isolated, using bioactivity-guided separation, from the bark of Odyendyea gabonensis (Pierre) Engler [syn. Quassia gabonensis Pierre]. The structure of 1 was determined by spectroscopic analysis and by semisynthesis from glaucarubolone. Complete (1)H and (13)C NMR assignments of compounds 1-8 were also established from detailed analysis of two-dimensional NMR spectra, and the reported configurations in odyendene (7) and odyendane (8) were corrected. Compound 1 showed potent cytotoxicity against multiple cancer cell lines. Further investigation using various types of breast and ovarian cancer cell lines suggested that 1 does not target the estrogen receptor or progesterone receptor. When tested against mammary epithelial proliferation in vivo using a Brca1/p53-deficient mice model, 1 also caused significant reduction in mammary duct branching.


Assuntos
Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Quassinas/isolamento & purificação , Quassinas/farmacologia , Animais , Antineoplásicos/química , Modelos Animais de Doenças , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Células KB , Camundongos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Casca de Planta/química , Quassinas/química , Estereoisomerismo
18.
J Med Chem ; 53(5): 2299-308, 2010 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-20148565

RESUMO

Neo-tanshinlactone (1) and its previously reported analogues, such as 2, are potent and selective in vitro antibreast cancer agents. The synthetic pathway to 2 was optimized from seven to five steps, with a better overall yield. Structure-activity relationships studies on these compounds revealed some key molecular determinants for this family of antibreast agents. Several derivatives (19-21 and 24) exerted potent and selective antibreast cancer activity with IC(50) values of 0.3, 0.2, 0.1, and 0.1 microg/mL, respectively, against the ZR-75-1 cell lines. Compound 24 was 2- to 3-fold more potent than 1 against SK-BR-3 and ZR-75-1. Importantly, 21 exhibited high selectivity; it was 23 times more active against ZR-75-1 than MCF-7. Compound 20 had an approximately 12-fold ratio of SK-BR-3/MCF-7 selectivity. In addition, analogue 2 showed potent activity against a ZR-75-1 xenograft model, but not PC-3 and MDA-MB-231 xenografts, as well as high selectivity against breast cancer cell line compared with normal breast tissue-derived cell lines. Further development of lead compounds 19-21 and 24 as clinical trial candidates is warranted.


Assuntos
Antineoplásicos/síntese química , Furanos/síntese química , Pironas/síntese química , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Feminino , Furanos/química , Furanos/farmacologia , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Espectrometria de Massas , Camundongos , Camundongos SCID , Pironas/química , Pironas/farmacologia , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Bioorg Med Chem ; 18(2): 803-8, 2010 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20034799

RESUMO

6-Phenyl-4H-furo[3,2-c]pyran-4-one derivatives based on neo-tashinlactone (1) were synthesized and evaluated as novel anti-breast cancer agents. Compounds 10-13, 23, 25, and 27 showed potent inhibition against the SK-BR-3 breast cancer cell line. Importantly, 25 and 27 showed the highest cancer cell line selectivity, being approximately 100-250-fold more potent against SK-BR-3 (ED(50) 0.28 and 0.44microM, respectively) compared with other cancer cell lines tested. In addition, 25 displayed low cytotoxicity against normal breast cell lines 184A1 and MCF10A. Compounds 25 and 27 merit further investigation in our continuing program to generate and develop selective anti-breast cancer agents.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Pironas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Estrutura Molecular , Pironas/síntese química , Pironas/química , Relação Estrutura-Atividade
20.
Mol Cancer Res ; 6(2): 194-204, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18314480

RESUMO

Integrin-mediated adhesion to the extracellular matrix plays a fundamental role in tumor metastasis. Salvicine, a novel diterpenoid quinone compound identified as a nonintercalative topoisomerase II poison, possesses a broad range of antitumor and antimetastatic activity. Here, the mechanism underlying the antimetastatic capacity of salvicine was investigated by exploring the effect of salvicine on integrin-mediated cell adhesion. Salvicine inhibited the adhesion of human breast cancer MDA-MB-435 cells to fibronectin and collagen without affecting nonspecific adhesion to poly-l-lysine. The fibronectin-dependent formation of focal adhesions and actin stress fibers was also inhibited by salvicine, leading to a rounded cell morphology. Furthermore, salvicine down-regulated beta(1) integrin ligand affinity, clustering and signaling via dephosphorylation of focal adhesion kinase and paxillin. Conversely, salvicine induced extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) phosphorylation. The effect of salvicine on beta(1) integrin function and cell adhesion was reversed by U0126 and SB203580, inhibitors of MAPK/ERK kinase 1/2 and p38 MAPK, respectively. Salvicine also induced the production of reactive oxygen species (ROS) that was reversed by ROS scavenger N-acetyl-l-cysteine. N-acetyl-l-cysteine additionally reversed the salvicine-induced activation of ERK and p38 MAPK, thereby maintaining functional beta(1) integrin activity and restoring cell adhesion and spreading. Together, this study reveals that salvicine activates ERK and p38 MAPK by triggering the generation of ROS, which in turn inhibits beta(1) integrin ligand affinity. These findings contribute to a better understanding of the antimetastatic activity of salvicine and shed new light on the complex roles of ROS and downstream signaling molecules, particularly p38 MAPK, in the regulation of integrin function and cell adhesion.


Assuntos
Antineoplásicos/farmacologia , Fibronectinas/metabolismo , Integrina beta1/metabolismo , Naftoquinonas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Adesões Focais/efeitos dos fármacos , Adesões Focais/enzimologia , Humanos , Integrina beta1/genética , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fibras de Estresse/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo
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