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1.
Mol Ther ; 30(4): 1610-1627, 2022 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-35151844

RESUMO

The FGFR3-TACC3 (F3-T3) fusion gene was discovered as an oncogenic molecule in glioblastoma and bladder cancers, and has subsequently been found in many cancer types. Notably, F3-T3 was found to be highly expressed in both untreated and matched recurrence glioblastoma under the concurrent radiotherapy and temozolomide (TMZ) treatment, suggesting that targeting F3-T3 is a valid strategy for treatment. Here, we show that the F3-T3 protein is a client of heat shock protein 90 (HSP90), forming a ternary complex with the cell division cycle 37 (CDC37). Deprivation of HSP90 or CDC37 disrupts the formation of the ternary complex, which destabilizes glycosylated F3-T3, and thereby suppresses F3-T3 oncogenic activity. Gliomas harboring F3-T3 are resistant to TMZ chemotherapy. HSP90 inhibitors sensitized F3-T3 glioma cells to TMZ via the inhibition of F3-T3 activation and potentiated TMZ-induced DNA damage. These results demonstrate that F3-T3 oncogenic function is dependent on the HSP90 chaperone system and suggests a new clinical option for targeting this genetic aberration in cancer.


Assuntos
Glioblastoma , Glioma , Carcinogênese , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Chaperoninas/genética , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Proteínas Associadas aos Microtúbulos/genética , Chaperonas Moleculares/genética , Recidiva Local de Neoplasia , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos , Temozolomida/farmacologia
2.
Cancer Commun (Lond) ; 41(5): 414-431, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33609419

RESUMO

BACKGROUND: Type II diabetes mellitus (DM2) is a significant risk factor for cancers, including breast cancer. However, a proper diabetic breast cancer mouse model is not well-established for treatment strategy design. Additionally, the precise diabetic signaling pathways that regulate cancer growth remain unresolved. In the present study, we established a suitable mouse model and demonstrated the pathogenic role of diabetes on breast cancer progression. METHODS: We successfully generated a transgenic mouse model of human epidermal growth factor receptor 2 positive (Her2+ or ERBB2) breast cancer with DM2 by crossing leptin receptor mutant (Leprdb/+ ) mice with MMTV-ErbB2/neu) mice. The mouse models were administrated with antidiabetic drugs to assess the impacts of controlling DM2 in affecting tumor growth. Magnetic resonance spectroscopic imaging was employed to analyze the tumor metabolism. RESULTS: Treatment with metformin/rosiglitazone in MMTV-ErbB2/Leprdb/db mouse model reduced serum insulin levels, prolonged overall survival, decreased cumulative tumor incidence, and inhibited tumor progression. Anti-insulin resistance medications also inhibited glycolytic metabolism in tumors in vivo as indicated by the reduced metabolic flux of hyperpolarized 13 C pyruvate-to-lactate reaction. The tumor cells from MMTV-ErbB2/Leprdb/db transgenic mice treated with metformin had reprogrammed metabolism by reducing levels of both oxygen consumption and lactate production. Metformin decreased the expression of Myc and pyruvate kinase isozyme 2 (PKM2), leading to metabolism reprogramming. Moreover, metformin attenuated the mTOR/AKT signaling pathway and altered adipokine profiles. CONCLUSIONS: MMTV-ErbB2/Leprdb/db mouse model was able to recapitulate diabetic HER2+ human breast cancer. Additionally, our results defined the signaling pathways deregulated in HER2+ breast cancer under diabetic condition, which can be intervened by anti-insulin resistance therapy.


Assuntos
Neoplasias da Mama , Diabetes Mellitus Tipo 2 , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Camundongos Transgênicos , Transdução de Sinais
3.
Mol Oncol ; 15(2): 462-472, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33107184

RESUMO

KRAS is a key oncogenic driver in lung adenocarcinoma (LUAD). Chromatin-remodeling gene SMARCA4 is comutated with KRAS in LUAD; however, the impact of SMARCA4 mutations on clinical outcome has not been adequately established. This study sought to shed light on the clinical significance of SMARCA4 mutations in LUAD. The association of SMARCA4 mutations with survival outcomes was interrogated in four independent cohorts totaling 564 patients: KRAS-mutant patients with LUAD who received nonimmunotherapy treatment from (a) The Cancer Genome Atlas (TCGA) and (b) the MSK-IMPACT Clinical Sequencing (MSK-CT) cohorts; and KRAS-mutant patients with LUAD who received immune checkpoint inhibitor-based immunotherapy treatment from (c) the MSK-IMPACT (MSK-IO) and (d) the Wake Forest Baptist Comprehensive Cancer Center (WFBCCC) immunotherapy cohorts. Of the patients receiving nonimmunotherapy treatment, in the TCGA cohort (n = 155), KRAS-mutant patients harboring SMARCA4 mutations (KS) showed poorer clinical outcome [P = 6e-04 for disease-free survival (DFS) and 0.031 for overall survival (OS), respectively], compared to KRAS-TP53 comutant (KP) and KRAS-only mutant (K) patients; in the MSK-CT cohort (n = 314), KS patients also exhibited shorter OS than KP (P = 0.03) or K (P = 0.022) patients. Of patients receiving immunotherapy, KS patients consistently exhibited the shortest progression-free survival (PFS; P = 0.0091) in the MSK-IO (n = 77), and the shortest PFS (P = 0.0026) and OS (P = 0.0014) in the WFBCCC (n = 18) cohorts, respectively. Therefore, mutations of SMARCA4 represent a genetic factor leading to adverse clinical outcome in lung adenocarcinoma treated by either nonimmunotherapy or immunotherapy.


Assuntos
Adenocarcinoma de Pulmão , Estudos de Coortes , DNA Helicases/genética , Imunoterapia , Neoplasias Pulmonares , Mutação , Proteínas Nucleares/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Fatores de Transcrição/genética , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/mortalidade , Adenocarcinoma de Pulmão/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/terapia , Masculino , Pessoa de Meia-Idade , Taxa de Sobrevida
4.
J Ovarian Res ; 13(1): 95, 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-32825834

RESUMO

BACKGROUND: Ovarian cancer is the leading cause of cancer-related death among women. Complete cytoreductive surgery followed by platinum-taxene chemotherapy has been the gold standard for a long time. Various compounds have been assessed in an attempt to combine them with conventional chemotherapy to improve survival rates or even overcome chemoresistance. Many studies have shown that an antidiabetic drug, metformin, has cytotoxic activity in different cancer models. However, the synergism of metformin as a neoadjuvant formula plus chemotherapy in clinical trials and basic studies remains unclear for ovarian cancer. METHODS: We applied two clinical databases to survey metformin use and ovarian cancer survival rate. The Cancer Genome Atlas dataset, an L1000 microarray with Gene Set Enrichment Analysis (GSEA) analysis, Western blot analysis and an animal model were used to study the activity of the AKT/mTOR pathway in response to the synergistic effects of neoadjuvant metformin combined with chemotherapy. RESULTS: We found that ovarian cancer patients treated with metformin had significantly longer overall survival than patients treated without metformin. The protein profile induced by low- concentration metformin in ovarian cancer predominantly involved the AKT/mTOR pathway. In combination with chemotherapy, the neoadjuvant metformin protocol showed beneficial synergistic effects in vitro and in vivo. CONCLUSIONS: This study shows that neoadjuvant metformin at clinically relevant dosages is efficacious in treating ovarian cancer, and the results can be used to guide clinical trials.


Assuntos
Antineoplásicos/administração & dosagem , Carboplatina/administração & dosagem , Metformina/administração & dosagem , Neoplasias Ovarianas/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Carboplatina/farmacologia , Sinergismo Farmacológico , Feminino , Humanos , Metformina/farmacologia , Camundongos , Terapia Neoadjuvante , Neoplasias Ovarianas/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Análise de Sobrevida , Serina-Treonina Quinases TOR/metabolismo , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Cancer Med ; 8(6): 3072-3085, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31033233

RESUMO

Tumor-infiltrating myeloid cells are the most abundant leukocyte population within tumors. Molecular cues from the tumor microenvironment promote the differentiation of immature myeloid cells toward an immunosuppressive phenotype. However, the in situ dynamics of the transcriptional reprogramming underlying this process are poorly understood. Therefore, we applied single cell RNA-seq (scRNA-seq) to computationally investigate the cellular composition and transcriptional dynamics of tumor and adjacent normal tissues from 4 early-stage non-small cell lung cancer (NSCLC) patients. Our scRNA-seq analyses identified 11 485 cells that varied in identity and gene expression traits between normal and tumor tissues. Among these, myeloid cell populations exhibited the most diverse changes between tumor and normal tissues, consistent with tumor-mediated reprogramming. Through trajectory analysis, we identified a differentiation path from CD14+ monocytes to M2 macrophages (monocyte-to-M2). This differentiation path was reproducible across patients, accompanied by increased expression of genes (eg, MRC1/CD206, MSR1/CD204, PPARG, TREM2) with significantly enriched functions (Oxidative phosphorylation and P53 pathway) and decreased expression of genes (eg, CXCL2, IL1B) with significantly enriched functions (TNF-α signaling via NF-κB and inflammatory response). Our analysis further identified a co-regulatory network implicating upstream transcription factors (JUN, NFKBIA) in monocyte-to-M2 differentiation, and activated ligand-receptor interactions (eg, SFTPA1-TLR2, ICAM1-ITGAM) suggesting intratumoral mechanisms whereby epithelial cells stimulate monocyte-to-M2 differentiation. Overall, our study identified the prevalent monocyte-to-M2 differentiation in NSCLC, accompanied by an intricate transcriptional reprogramming mediated by specific transcriptional activators and intercellular crosstalk involving ligand-receptor interactions.


Assuntos
Plasticidade Celular/genética , Células Mieloides/metabolismo , RNA-Seq/métodos , Humanos , Transdução de Sinais , Microambiente Tumoral
7.
Nat Commun ; 8(1): 939, 2017 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-29038521

RESUMO

EGFR signaling is implicated in NF-κB activation. However, the concrete mechanisms by which the core transducer of NF-κB signaling pathway, RelA/p65 is regulated under EGFR activation remains to be further clarified. Here, we show that EGF stimulation induces PKCε-dependent phosphorylation of migration and invasion inhibitory protein (MIIP) at Ser303; this phosphorylation promotes the interaction between MIIP and RelA in the nucleus, by which MIIP prevents histone deacetylase 6 (HDAC6)-mediated RelA deacetylation, and thus enhances transcriptional activity of RelA and facilitates tumor metastasis. Meanwhile PP1, which functions as a phosphatase, is found to mediate MIIP-S303 dephosphorylation and its expression level inversely correlates with metastatic capability of tumor cells. Moreover, clinical analyses indicate the level of MIIP-S303 phosphorylation correlates with colorectal cancer (CRC) metastasis and prognosis. These findings uncover an unidentified mechanism underlying the precise regulation of NF-κB by EGF, and highlight the critical role of nuclear MIIP in tumor metastasis.In colorectal cancer, EGFR signalling is implicated in metastasis. Here, the authors unravel a mechanism through which EGF stimulation induces MIIP phosphorylation, leading to MIIP interacting with RelA-this prevents RelA deactylation and enhances transcriptional activity, facilitating metastasis.


Assuntos
Proteínas de Transporte/metabolismo , Neoplasias Colorretais/metabolismo , Proteína Quinase C-épsilon/metabolismo , Fator de Transcrição RelA/metabolismo , Acetilação , Animais , Células CACO-2 , Proteínas de Transporte/genética , Linhagem Celular Tumoral , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Fator de Crescimento Epidérmico/farmacologia , Feminino , Células HCT116 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos Endogâmicos BALB C , Camundongos Nus , Metástase Neoplásica , Fosforilação/efeitos dos fármacos , Ligação Proteica , Interferência de RNA , Serina/metabolismo , Transplante Heterólogo
8.
Nat Commun ; 8: 14799, 2017 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-28300060

RESUMO

Dynamic changes in histone modifications under various physiological cues play important roles in gene transcription and cancer. Identification of new histone marks critical for cancer development is of particular importance. Here we show that, in a glucose-dependent manner, E3 ubiquitin ligase NEDD4 ubiquitinates histone H3 on lysine 23/36/37 residues, which specifically recruits histone acetyltransferase GCN5 for subsequent H3 acetylation. Genome-wide analysis of chromatin immunoprecipitation followed by sequencing reveals that NEDD4 regulates glucose-induced H3 K9 acetylation at transcription starting site and enhancer regions. Integrative analysis of ChIP-seq and microarray data sets also reveals a consistent role of NEDD4 in transcription activation and H3 K9 acetylation in response to glucose. Functionally, we show that NEDD4-mediated H3 ubiquitination, by transcriptionally activating IL1α, IL1ß and GCLM, is important for tumour sphere formation. Together, our study reveals the mechanism for glucose-induced transcriptome reprograming and epigenetic regulation in cancer by inducing NEDD4-dependent H3 ubiquitination.


Assuntos
Carcinogênese/metabolismo , Histonas/metabolismo , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Ubiquitinação , Acetilação/efeitos dos fármacos , Animais , Carcinogênese/genética , Linhagem Celular Tumoral , Epigênese Genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Glucose/farmacologia , Células HEK293 , Humanos , Lisina/metabolismo , Camundongos Nus , Ubiquitina-Proteína Ligases Nedd4/genética , Transplante Heterólogo
9.
Nat Cell Biol ; 19(1): 38-51, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27918549

RESUMO

The understanding of how hypoxia stabilizes and activates HIF1α in the nucleus with related oncogenic signals could revolutionize targeted therapy for cancers. Here, we find that histone H2AX displays oncogenic activity by serving as a crucial regulator of HIF1α signalling. H2AX interacts with HIF1α to prevent its degradation and nuclear export in order to allow successful VHL-independent HIF1α transcriptional activation. We show that mono-ubiquitylation and phosphorylation of H2AX, which are strictly mediated by hypoxia-induced E3 ligase activity of TRAF6 and ATM, critically regulate HIF1α-driven tumorigenesis. Importantly, TRAF6 and γH2AX are overexpressed in human breast cancer, correlate with activation of HIF1α signalling, and predict metastatic outcome. Thus, TRAF6 and H2AX overexpression and γH2AX-mediated HIF1α enrichment in the nucleus of cancer cells lead to overactivation of HIF1α-driven tumorigenesis, glycolysis and metastasis. Our findings suggest that TRAF6-mediated mono-ubiquitylation and subsequent phosphorylation of H2AX may serve as potential means for cancer diagnosis and therapy.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Carcinogênese/metabolismo , Histonas/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Transdução de Sinais , Fator 6 Associado a Receptor de TNF/metabolismo , Animais , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Carcinogênese/patologia , Hipóxia Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Proliferação de Células , Senescência Celular , Feminino , Fibroblastos/metabolismo , Técnicas de Silenciamento de Genes , Glicólise , Humanos , Imuno-Histoquímica , Camundongos , Metástase Neoplásica , Estabilidade Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Resultado do Tratamento , Ubiquitina/metabolismo
10.
Cancer Res ; 75(22): 4708-17, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26420214

RESUMO

Hyperpolarized [1-(13)C]-pyruvate has shown tremendous promise as an agent for imaging tumor metabolism with unprecedented sensitivity and specificity. Imaging hyperpolarized substrates by magnetic resonance is unlike traditional MRI because signals are highly transient and their spatial distribution varies continuously over their observable lifetime. Therefore, new imaging approaches are needed to ensure optimal measurement under these circumstances. Constrained reconstruction algorithms can integrate prior information, including biophysical models of the substrate/target interaction, to reduce the amount of data that is required for image analysis and reconstruction. In this study, we show that metabolic MRI with hyperpolarized pyruvate is biased by tumor perfusion and present a new pharmacokinetic model for hyperpolarized substrates that accounts for these effects. The suitability of this model is confirmed by statistical comparison with alternates using data from 55 dynamic spectroscopic measurements in normal animals and murine models of anaplastic thyroid cancer, glioblastoma, and triple-negative breast cancer. The kinetic model was then integrated into a constrained reconstruction algorithm and feasibility was tested using significantly undersampled imaging data from tumor-bearing animals. Compared with naïve image reconstruction, this approach requires far fewer signal-depleting excitations and focuses analysis and reconstruction on new information that is uniquely available from hyperpolarized pyruvate and its metabolites, thus improving the reproducibility and accuracy of metabolic imaging measurements.


Assuntos
Radioisótopos de Carbono/farmacocinética , Imageamento por Ressonância Magnética/métodos , Neoplasias/diagnóstico por imagem , Ácido Pirúvico/farmacocinética , Compostos Radiofarmacêuticos/farmacocinética , Algoritmos , Animais , Linhagem Celular Tumoral , Humanos , Processamento de Imagem Assistida por Computador/métodos , Cinética , Masculino , Camundongos , Camundongos Nus , Modelos Teóricos , Cintilografia
11.
Oncotarget ; 6(23): 19721-34, 2015 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-26254224

RESUMO

p27 is a critical CDK inhibitor involved in cell cycle regulation, and its stability is critical for cell proliferation. Constitutive photomorphogenic 1 (COP1) is a RING-containing E3 ubiquitin ligase involved in regulating important target proteins for cell growth, but its biological activity in cell cycle progression is not well characterized. Here, we report that p27Kip1 levels are accumulated in G1 phase, with concurrent reduction of COP1 levels. Mechanistic studies show that COP1 directly interacts with p27 through a VP motif on p27 and functions as an E3 ligase of p27 to accelerate the ubiquitin-mediated degradation of p27. Also, COP1-p27 axis deregulation is involved in tumorigenesis. These findings define a new mechanism for posttranslational regulation of p27 and provide insight into the characteristics of COP1-overexpressing cancers.


Assuntos
Proliferação de Células , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Neoplasias/enzimologia , Processamento de Proteína Pós-Traducional , Proteólise , Carga Tumoral , Ubiquitina-Proteína Ligases/metabolismo , Animais , Sítios de Ligação , Ciclo Celular , Inibidor de Quinase Dependente de Ciclina p27/genética , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Células HeLa , Humanos , Camundongos Nus , Neoplasias/genética , Neoplasias/patologia , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Transdução de Sinais , Fatores de Tempo , Transfecção , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
12.
Nat Commun ; 6: 7530, 2015 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-26179207

RESUMO

Extensive reprogramming of cellular energy metabolism is a hallmark of cancer. Despite its importance, the molecular mechanism controlling this tumour metabolic shift remains not fully understood. Here we show that 14-3-3σ regulates cancer metabolic reprogramming and protects cells from tumorigenic transformation. 14-3-3σ opposes tumour-promoting metabolic programmes by enhancing c-Myc poly-ubiquitination and subsequent degradation. 14-3-3σ demonstrates the suppressive impact on cancer glycolysis, glutaminolysis, mitochondrial biogenesis and other major metabolic processes of tumours. Importantly, 14-3-3σ expression levels predict overall and recurrence-free survival rates, tumour glucose uptake and metabolic gene expression in breast cancer patients. Thus, these results highlight that 14-3-3σ is an important regulator of tumour metabolism, and loss of 14-3-3σ expression is critical for cancer metabolic reprogramming. We anticipate that pharmacologically elevating the function of 14-3-3σ in tumours could be a promising direction for targeted anticancer metabolism therapy development in future.


Assuntos
Proteínas 14-3-3/genética , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Metabolismo Energético/genética , Exorribonucleases/genética , Regulação Neoplásica da Expressão Gênica , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas 14-3-3/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Intervalo Livre de Doença , Exorribonucleases/metabolismo , Feminino , Técnicas de Inativação de Genes , Glutamina/metabolismo , Glicólise/genética , Células HCT116 , Humanos , Pessoa de Meia-Idade , Biogênese de Organelas , Prognóstico , Proteólise , Ubiquitinação/genética , Adulto Jovem
13.
Mol Cell ; 58(6): 989-1000, 2015 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-26051179

RESUMO

The regulation of RagA(GTP) is important for amino-acid-induced mTORC1 activation. Although GATOR1 complex has been identified as a negative regulator for mTORC1 by hydrolyzing RagA(GTP), how GATOR1 is recruited to RagA to attenuate mTORC1 signaling remains unclear. Moreover, how mTORC1 signaling is terminated upon amino acid stimulation is also unknown. We show that the recruitment of GATOR1 to RagA is induced by amino acids in an mTORC1-dependent manner. Skp2 E3 ligase drives K63-linked ubiquitination of RagA, which facilitates GATOR1 recruitment and RagA(GTP) hydrolysis, thereby providing a negative feedback loop to attenuate mTORC1 lysosomal recruitment and prevent mTORC1 hyperactivation. We further demonstrate that Skp2 promotes autophagy but inhibits cell size and cilia growth through RagA ubiquitination and mTORC1 inhibition. We thereby propose a negative feedback whereby Skp2-mediated RagA ubiquitination recruits GATOR1 to restrict mTORC1 signaling upon sustained amino acid stimulation, which serves a critical mechanism to maintain proper cellular functions.


Assuntos
Aminoácidos/farmacologia , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Complexos Multiproteicos/metabolismo , Proteínas Quinases Associadas a Fase S/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Autofagia/genética , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Retroalimentação Fisiológica/efeitos dos fármacos , Guanosina Trifosfato/metabolismo , Células HEK293 , Humanos , Immunoblotting , Lisina/metabolismo , Lisossomos/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Camundongos Knockout , Microscopia Confocal , Modelos Biológicos , Células NIH 3T3 , Ligação Proteica/efeitos dos fármacos , Interferência de RNA , Proteínas Quinases Associadas a Fase S/genética , Ubiquitinação/efeitos dos fármacos
14.
Oncotarget ; 6(12): 10016-29, 2015 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-25881542

RESUMO

Brain metastasis is a major cause of morbidity and mortality in patients with breast cancer. Our previous studies indicated that Stat3 plays an important role in brain metastasis. Here, we present evidence that Stat3 functions at the level of the microenvironment of brain metastases. Stat3 controlled constitutive and inducible VEGFR2 expression in tumor-associated brain endothelial cells. Furthermore, inhibition of Stat3 by WP1066 decreased the incidence of brain metastases and increased survival in a preclinical model of breast cancer brain metastasis. WP1066 inhibited Stat3 activation in tumor-associated endothelial cells, reducing their infiltration and angiogenesis. WP1066 also inhibited breast cancer cell invasion. Our results indicate that WP1066 can inhibit tumor angiogenesis and brain metastasis mediated by Stat3 in endothelial and tumor cells.


Assuntos
Neoplasias Encefálicas/secundário , Neoplasias da Mama/patologia , Comunicação Celular/efeitos dos fármacos , Células Endoteliais/patologia , Piridinas/farmacologia , Fator de Transcrição STAT3/antagonistas & inibidores , Fator de Transcrição STAT3/metabolismo , Tirfostinas/farmacologia , Animais , Neoplasias Encefálicas/prevenção & controle , Neoplasias da Mama/irrigação sanguínea , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Comunicação Celular/fisiologia , Linhagem Celular Tumoral , Células Endoteliais/metabolismo , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Metástase Neoplásica , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/biossíntese , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Nat Commun ; 5: 5384, 2014 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-25395170

RESUMO

Cullin-RING ubiquitin ligases (CRLs) are critical in ubiquitinating Myc, while COP9 signalosome (CSN) controls neddylation of Cullin in CRL. The mechanistic link between Cullin neddylation and Myc ubiquitination/degradation is unclear. Here we show that Myc is a target of the CSN subunit 6 (CSN6)-Cullin signalling axis and that CSN6 is a positive regulator of Myc. CSN6 enhanced neddylation of Cullin-1 and facilitated autoubiquitination/degradation of Fbxw7, a component of CRL involved in Myc ubiquitination, thereby stabilizing Myc. Csn6 haplo-insufficiency decreased Cullin-1 neddylation but increased Fbxw7 stability to compromise Myc stability and activity in an Eµ-Myc mouse model, resulting in decelerated lymphomagenesis. We found that CSN6 overexpression, which leads to aberrant expression of Myc target genes, is frequent in human cancers. Together, these results define a mechanism for the regulation of Myc stability through the CSN-Cullin-Fbxw7 axis and provide insights into the correlation of CSN6 overexpression with Myc stabilization/activation during tumorigenesis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Carcinogênese/genética , Peptídeo Hidrolases/fisiologia , Proteínas Proto-Oncogênicas c-myc/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/biossíntese , Animais , Complexo do Signalossomo COP9 , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/fisiologia , Técnicas de Silenciamento de Genes , Linfoma/metabolismo , Linfoma/fisiopatologia , Camundongos , Camundongos Transgênicos/genética , Neoplasias Experimentais/genética , Peptídeo Hidrolases/biossíntese , Proteínas Proto-Oncogênicas c-myc/biossíntese , Proteínas Ligases SKP Culina F-Box/fisiologia , Transcrição Gênica/fisiologia , Ubiquitinação
16.
Cell Biosci ; 4(1): 59, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25309720

RESUMO

Akt regulates critical cellular processes including cell survival and proliferation, glucose metabolism, cell migration, cancer progression and metastasis through phosphorylation of a variety of downstream targets. The Akt pathway is one of the most prevalently hyperactivated signaling pathways in human cancer, thus, research deciphering molecular mechanisms which underlie the aberrant Akt activation has received enormous attention. The PI3K-dependent Akt serine/threonine phosphorylation by PDK1 and mTORC2 has long been thought to be the primary mechanism accounting for Akt activation. However, this regulation alone does not sufficiently explain how Akt hyperactivation can occur in tumors with normal levels of PI3K/PTEN activity. Mounting evidence demonstrates that aberrant Akt activation can be attributed to other posttranslational modifications, which include tyrosine phosphorylation, O-GlcNAcylation, as well as lysine modifications: ubiquitination, SUMOylation and acetylation. Among them, K63-linked ubiquitination has been shown to be a critical step for Akt signal activation by facilitating its membrane recruitment. Deficiency of E3 ligases responsible for growth factor-induced Akt activation leads to tumor suppression. Therefore, a comprehensive understanding of posttranslational modifications in Akt regulation will offer novel strategies for cancer therapy.

17.
J Natl Cancer Inst ; 106(7)2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24957076

RESUMO

BACKGROUND: Obesity increases the risk of cancer death among postmenopausal women with estrogen receptor-positive (ER+) breast cancer, but the direct evidence for the mechanisms is lacking. The purpose of this study is to demonstrate direct evidence for the mechanisms mediating this epidemiologic phenomenon. METHODS: We analyzed transcriptomic profiles of pretreatment biopsies from a prospective cohort of 137 ER+ breast cancer patients. We generated transgenic (MMTV-TGFα;A (y) /a) and orthotopic/syngeneic (A (y) /a) obese mouse models to investigate the effect of obesity on tumorigenesis and tumor progression and to determine biological mechanisms using whole-genome transcriptome microarrays and protein analyses. We used a coculture system to examine the impact of adipocytes/adipokines on breast cancer cell proliferation. All statistical tests were two-sided. RESULTS: Functional transcriptomic analysis of patients revealed the association of obesity with 59 biological functional changes (P < .05) linked to cancer hallmarks. Gene enrichment analysis revealed enrichment of AKT-target genes (P = .04) and epithelial-mesenchymal transition genes (P = .03) in patients. Our obese mouse models demonstrated activation of the AKT/mTOR pathway in obesity-accelerated mammary tumor growth (3.7- to 7.0-fold; P < .001; n = 6-7 mice per group). Metformin or everolimus can suppress obesity-induced secretion of adipokines and breast tumor formation and growth (0.5-fold, P = .04; 0.3-fold, P < .001, respectively; n = 6-8 mice per group). The coculture model revealed that adipocyte-secreted adipokines (eg, TIMP-1) regulate adipocyte-induced breast cancer cell proliferation and invasion. Metformin suppress adipocyte-induced cell proliferation and adipocyte-secreted adipokines in vitro. CONCLUSIONS: Adipokine secretion and AKT/mTOR activation play important roles in obesity-accelerated breast cancer aggressiveness in addition to hyperinsulinemia, estrogen signaling, and inflammation. Metformin and everolimus have potential for therapeutic interventions of ER+ breast cancer patients with obesity.


Assuntos
Antineoplásicos/farmacologia , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/etiologia , Neoplasias da Mama/metabolismo , Metformina/farmacologia , Obesidade/complicações , Obesidade/metabolismo , Receptores de Estrogênio/metabolismo , Sirolimo/análogos & derivados , Transcriptoma , Adipócitos , Adipocinas/metabolismo , Idoso , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Everolimo , Feminino , Humanos , Estimativa de Kaplan-Meier , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Obesidade/epidemiologia , Obesidade/genética , Pós-Menopausa , Estudos Prospectivos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/metabolismo
18.
Cell Cycle ; 11(22): 4181-90, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-23095642

RESUMO

HER2/neu oncogene is frequently overexpressed in various types of cancer, and the (PI3K)-Akt signaling pathway is often activated in HER2-overexpressing cancer cells. CSN6, subunit 6 of the COP9 signalosome complex, is pivotal in regulating MDM2 to destabilize p53, but its upstream regulators remain unclear. Here we show that the HER2-Akt axis is linked to CSN6 regulation, and that Akt is a positive regulator of CSN6. Ectopic expression of Akt can increase the expression of CSN6; accordingly, Akt inhibition leads to CSN6 destabilization. Mechanistic studies show that Akt causes CSN6 phosphorylation at Ser 60, which, in turn, reduces ubiquitin-mediated protein degradation of CSN6. Significantly, Akt's positive impact on CSN6 elevation translates into p53 degradation, potentiating transformational activity and increasing DNA damage. Akt inhibition can attenuate these defects caused by CSN6. These data suggest that Akt is an important positive regulator of CSN6, and that activation of Akt in many types of cancer could lead to abnormal elevation of CSN6 and result in downregulated p53 and increased DNA damage, which promotes cancer cell growth.


Assuntos
Complexos Multiproteicos/metabolismo , Peptídeo Hidrolases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor ErbB-2/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Sequência de Aminoácidos , Aurora Quinases , Complexo do Signalossomo COP9 , Linhagem Celular Tumoral , Dano ao DNA , Células HCT116 , Células HEK293 , Humanos , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Estabilidade Proteica , Subunidades Proteicas/metabolismo , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Transdução de Sinais , Ubiquitina/metabolismo , Ubiquitinação
19.
Proc Natl Acad Sci U S A ; 109(24): E1513-22, 2012 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-22611192

RESUMO

Aurora B is a mitotic checkpoint kinase that plays a pivotal role in the cell cycle, ensuring correct chromosome segregation and normal progression through mitosis. Aurora B is overexpressed in many types of human cancers, which has made it an attractive target for cancer therapies. Tumor suppressor p53 is a genome guardian and important negative regulator of the cell cycle. Whether Aurora B and p53 are coordinately regulated during the cell cycle is not known. We report that Aurora B directly interacts with p53 at different subcellular localizations and during different phases of the cell cycle (for instance, at the nucleus in interphase and the centromeres in prometaphase of mitosis). We show that Aurora B phosphorylates p53 at S183, T211, and S215 to accelerate the degradation of p53 through the polyubiquitination-proteasome pathway, thus functionally suppressing the expression of p53 target genes involved in cell cycle inhibition and apoptosis (e.g., p21 and PUMA). Pharmacologic inhibition of Aurora B in cancer cells with WT p53 increased p53 protein level and expression of p53 target genes to inhibit tumor growth. Together, these results define a mechanism of p53 inactivation during the cell cycle and imply that oncogenic hyperactivation or overexpression of Aurora B may compromise the tumor suppressor function of p53. We have elucidated the antineoplastic mechanism for Aurora B kinase inhibitors in cancer cells with WT p53.


Assuntos
Proteínas Serina-Treonina Quinases/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Aurora Quinase B , Aurora Quinases , Humanos , Interfase , Mitose , Fosforilação , Ligação Proteica , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteólise , Frações Subcelulares/enzimologia , Frações Subcelulares/metabolismo , Transcrição Gênica , Ubiquitinação
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