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1.
Int Angiol ; 42(5): 427-435, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37962898

RESUMO

BACKGROUND: Chronic venous insufficiency (CVI) and diabetes mellitus (DM) pose significant burdens to patients and healthcare systems. While the two diseases share a number of commonalities in risk factors and pathophysiology, they are often assessed and managed separately. This can lead to a worsening of comorbidities and limitations in a patient's quality of life. This project aims to develop recommendations to enhance the identification and treatment of patients with concomitant CVI and DM. METHODS: Using a modified Delphi method, a panel of experts developed 38 Likert Scale and two multiple choice questions across six key themes. These were used to form an online survey which was disseminated through a convenience sampling approach to CVI and DM healthcare professionals across Europe, Central America, South America, and the Middle East. The threshold for consensus was set at ≥75%. RESULTS: A total of 238 responses were received. 27/38 statements attained >90% agreement, nine of 38 attained between 75-90%, and two failed to meet the threshold (<75%). The awareness around the impact of the two diseases was high, but a gap was highlighted in the identification of patients with concomitant CVI and DM. CONCLUSIONS: The high level of agreement shows that healthcare professionals are aware of the gaps in identification and treatment of patients with concomitant CVI and DM, and of the need to approach this as a combined therapy area. An algorithm is proposed to help the identification of at-risk patients and to provide recommendations on the management of patients with concomitant disease.


Assuntos
Diabetes Mellitus , Insuficiência Venosa , Humanos , Qualidade de Vida , Técnica Delphi , Insuficiência Venosa/diagnóstico , Insuficiência Venosa/terapia , Insuficiência Venosa/complicações , Doença Crônica
2.
J Exp Med ; 220(11)2023 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-37642941

RESUMO

Targeting the PI3K-AKT-mTOR pathway is a promising therapeutic strategy for breast cancer treatment. However, low response rates and development of resistance to PI3K-AKT-mTOR inhibitors remain major clinical challenges. Here, we show that MYC activation drives resistance to mTOR inhibitors (mTORi) in breast cancer. Multiomic profiling of mouse invasive lobular carcinoma (ILC) tumors revealed recurrent Myc amplifications in tumors that acquired resistance to the mTORi AZD8055. MYC activation was associated with biological processes linked to mTORi response and counteracted mTORi-induced translation inhibition by promoting translation of ribosomal proteins. In vitro and in vivo induction of MYC conferred mTORi resistance in mouse and human breast cancer models. Conversely, AZD8055-resistant ILC cells depended on MYC, as demonstrated by the synergistic effects of mTORi and MYCi combination treatment. Notably, MYC status was significantly associated with poor response to everolimus therapy in metastatic breast cancer patients. Thus, MYC is a clinically relevant driver of mTORi resistance that may stratify breast cancer patients for mTOR-targeted therapies.


Assuntos
Neoplasias da Mama , Humanos , Animais , Camundongos , Feminino , Neoplasias da Mama/tratamento farmacológico , Inibidores de MTOR , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Serina-Treonina Quinases TOR
4.
Nature ; 608(7923): 609-617, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35948633

RESUMO

Somatic hotspot mutations and structural amplifications and fusions that affect fibroblast growth factor receptor 2 (encoded by FGFR2) occur in multiple types of cancer1. However, clinical responses to FGFR inhibitors have remained variable1-9, emphasizing the need to better understand which FGFR2 alterations are oncogenic and therapeutically targetable. Here we apply transposon-based screening10,11 and tumour modelling in mice12,13, and find that the truncation of exon 18 (E18) of Fgfr2 is a potent driver mutation. Human oncogenomic datasets revealed a diverse set of FGFR2 alterations, including rearrangements, E1-E17 partial amplifications, and E18 nonsense and frameshift mutations, each causing the transcription of E18-truncated FGFR2 (FGFR2ΔE18). Functional in vitro and in vivo examination of a compendium of FGFR2ΔE18 and full-length variants pinpointed FGFR2-E18 truncation as single-driver alteration in cancer. By contrast, the oncogenic competence of FGFR2 full-length amplifications depended on a distinct landscape of cooperating driver genes. This suggests that genomic alterations that generate stable FGFR2ΔE18 variants are actionable therapeutic targets, which we confirmed in preclinical mouse and human tumour models, and in a clinical trial. We propose that cancers containing any FGFR2 variant with a truncated E18 should be considered for FGFR-targeted therapies.


Assuntos
Éxons , Deleção de Genes , Terapia de Alvo Molecular , Neoplasias , Oncogenes , Inibidores de Proteínas Quinases , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos , Animais , Éxons/genética , Humanos , Camundongos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/patologia , Oncogenes/genética , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/metabolismo
5.
Oncoimmunology ; 9(1): 1724049, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32117586

RESUMO

Effective treatment of invasive lobular carcinoma (ILC) of the breast is hampered by late detection, invasive growth, distant metastasis, and poor response to chemotherapy. Phosphoinositide 3-kinase (PI3K) signaling, one of the major druggable oncogenic signaling networks, is frequently activated in ILC. We investigated treatment response and resistance to AZD8055, an inhibitor of mammalian target of rapamycin (mTOR), in the K14-cre;Cdh1Flox/Flox;Trp53Flox/Flox (KEP) mouse model of metastatic ILC. Inhibition of mTOR signaling blocked the growth of primary KEP tumors as well as the progression of metastatic disease. However, primary tumors and distant metastases eventually acquired resistance after long-term AZD8055 treatment, despite continued effective suppression of mTOR signaling in cancer cells. Interestingly, therapeutic responses were associated with increased expression of genes related to antigen presentation. Consistent with this observation, increased numbers of tumor-infiltrating major histocompatibility complex class II-positive (MHCII+) immune cells were observed in treatment-responsive KEP tumors. Acquisition of treatment resistance was associated with loss of MHCII+ cells and reduced expression of genes related to the adaptive immune system. The therapeutic efficacy of mTOR inhibition was reduced in Rag1-/- mice lacking mature T and B lymphocytes, compared to immunocompetent mice. Furthermore, therapy responsiveness could be partially rescued by transplanting AZD8055-resistant KEP tumors into treatment-naïve immunocompetent hosts. Collectively, these data indicate that the PI3K signaling pathway is an attractive therapeutic target in invasive lobular carcinoma, and that part of the therapeutic effect of mTOR inhibition is mediated by the adaptive immune system.


Assuntos
Neoplasias da Mama , Carcinoma Lobular , Animais , Neoplasias da Mama/tratamento farmacológico , Carcinoma Lobular/tratamento farmacológico , Feminino , Humanos , Sistema Imunitário , Camundongos , Fosfatidilinositol 3-Quinases , Serina-Treonina Quinases TOR/genética
6.
J Clin Invest ; 129(7): 2702-2716, 2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-31039140

RESUMO

The development of metastatic melanoma is thought to require the dynamic shifting of neoplastic cells between proliferative and invasive phenotypes. Contrary to this conventional "phenotype switching" model, we now show that disease progression can involve malignant melanoma cells simultaneously displaying proliferative and invasive properties. Using a genetic mouse model of melanoma in combination with in vitro analyses of melanoma cell lines, we found that conditional deletion of the downstream signaling molecule Smad4, which abrogates all canonical TGF-ß signaling, indeed inhibits both tumor growth and metastasis. Conditional deletion of the inhibitory signaling factor Smad7, however, generated cells that are both highly invasive and proliferative, indicating that invasiveness is compatible with a high proliferation rate. In fact, conditional Smad7 deletion led to sustained melanoma growth and at the same time promoted massive metastasis formation, a result consistent with data indicating that low SMAD7 levels in patient tumors are associated with a poor survival. Our findings reveal that modulation of SMAD7 levels can overcome the need for phenotype switching during tumor progression and may thus represent a novel therapeutic target in metastatic disease.


Assuntos
Melanoma/metabolismo , Transdução de Sinais , Proteína Smad7/metabolismo , Animais , Intervalo Livre de Doença , Humanos , Melanoma/genética , Melanoma/mortalidade , Melanoma/patologia , Camundongos , Camundongos Knockout , Invasividade Neoplásica , Metástase Neoplásica , Proteína Smad4/genética , Proteína Smad4/metabolismo , Proteína Smad7/genética , Taxa de Sobrevida
7.
Cell Stem Cell ; 24(4): 637-653.e9, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30951662

RESUMO

Increasing evidence suggests that cancer cells highjack developmental programs for disease initiation and progression. Melanoma arises from melanocytes that originate during development from neural crest stem cells (NCSCs). Here, we identified the transcription factor Yin Yang 1 (Yy1) as an NCSCs regulator. Conditional deletion of Yy1 in NCSCs resulted in stage-dependent hypoplasia of all major neural crest derivatives due to decreased proliferation and increased cell death. Moreover, conditional ablation of one Yy1 allele in a melanoma mouse model prevented tumorigenesis, indicating a particular susceptibility of melanoma cells to reduced Yy1 levels. Combined RNA sequencing (RNA-seq), chromatin immunoprecipitation (ChIP)-seq, and untargeted metabolomics demonstrated that YY1 governs multiple metabolic pathways and protein synthesis in both NCSCs and melanoma. In addition to directly regulating a metabolic gene set, YY1 can act upstream of MITF/c-MYC as part of a gene regulatory network controlling metabolism. Thus, both NCSC development and melanoma formation depend on an intricate YY1-controlled metabolic program.


Assuntos
Melanoma/metabolismo , Melanoma/patologia , Crista Neural/citologia , Crista Neural/metabolismo , Fator de Transcrição YY1/metabolismo , Animais , Linhagem Celular Tumoral , Humanos , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Fator de Transcrição YY1/deficiência
8.
Cancer Cell ; 34(1): 69-84.e14, 2018 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-30008323

RESUMO

Human melanomas frequently harbor amplifications of EZH2. However, the contribution of EZH2 to melanoma formation has remained elusive. Taking advantage of murine melanoma models, we show that EZH2 drives tumorigenesis from benign BrafV600E- or NrasQ61K-expressing melanocytes by silencing of genes relevant for the integrity of the primary cilium, a signaling organelle projecting from the surface of vertebrate cells. Consequently, gain of EZH2 promotes loss of primary cilia in benign melanocytic lesions. In contrast, blockade of EZH2 activity evokes ciliogenesis and cilia-dependent growth inhibition in malignant melanoma. Finally, we demonstrate that loss of cilia enhances pro-tumorigenic WNT/ß-catenin signaling, and is itself sufficient to drive metastatic melanoma in benign cells. Thus, primary cilia deconstruction is a key process in EZH2-driven melanomagenesis.


Assuntos
Movimento Celular , Proliferação de Células , Cílios/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Melanócitos/metabolismo , Melanoma/metabolismo , Neoplasias Cutâneas/metabolismo , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Cílios/genética , Cílios/patologia , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Feminino , GTP Fosfo-Hidrolases/genética , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Metástase Linfática , Masculino , Melanócitos/patologia , Melanoma/genética , Melanoma/secundário , Proteínas de Membrana/genética , Camundongos Nus , Camundongos Transgênicos , Proteínas Proto-Oncogênicas B-raf/genética , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Via de Sinalização Wnt , beta Catenina/genética , beta Catenina/metabolismo
10.
Expert Rev Pharmacoecon Outcomes Res ; 18(1): 107-117, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28737469

RESUMO

BACKGROUND: Uncomplicated lower urinary tract infections (UTIs) occur in approximately 50% of women, and 20-30% experience recurrent UTI. Data on UTIs and quality of life (QoL) in Europe are limited. METHODS: This was an anonymous, self-administered web-based survey conducted in 5 countries (Germany, Switzerland, Poland, Russia and Italy), on adult women who had experienced recurrent UTI and were affected by acute UTI currently or within 4 weeks of study entry. Questions covered disease course; management; social and economic burden; education, income, and health insurance status. QoL was evaluated using the SF-12v2. RESULTS: Participants reported a mean of 5.15 UTI symptoms, ranging from 4.85 - 5.38 in Russia and Germany. There was a mean of 2.78 doctor visits per year (1.74 - 3.71 in Russia and Germany; p < 0.0001). 80.3% of participants had been treated with antibiotics, mean prescriptions ranged from 2.17 (Poland) to 3.36 (Germany) per person per year. A mean of 3.09 days sick leave due to UTIs, and 3.45 days of limited activities, were reported. Although 73.8% of participants had tried prophylaxis recurrence was common and associated with mental stress for a high proportion of women. CONCLUSIONS: Our results indicate that recurrent UTIs have a significant impact on QoL of women in Europe.


Assuntos
Antibacterianos/uso terapêutico , Efeitos Psicossociais da Doença , Qualidade de Vida , Infecções Urinárias/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Europa (Continente)/epidemiologia , Feminino , Inquéritos Epidemiológicos , Humanos , Seguro Saúde/estatística & dados numéricos , Internet , Pessoa de Meia-Idade , Recidiva , Licença Médica/estatística & dados numéricos , Estresse Psicológico/epidemiologia , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/economia , Adulto Jovem
11.
Cell Rep ; 20(4): 854-867, 2017 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-28746871

RESUMO

Immunotherapy and particularly immune checkpoint inhibitors have resulted in remarkable clinical responses in patients with immunogenic tumors, although most cancers develop resistance to immunotherapy. The molecular mechanisms of tumor resistance to immunotherapy remain poorly understood. We now show that induction of the histone methyltransferase Ezh2 controls several tumor cell-intrinsic and extrinsic resistance mechanisms. Notably, T cell infiltration selectively correlated with high EZH2-PRC2 complex activity in human skin cutaneous melanoma. During anti-CTLA-4 or IL-2 immunotherapy in mice, intratumoral tumor necrosis factor-α (TNF-α) production and T cell accumulation resulted in increased Ezh2 expression in melanoma cells, which in turn silenced their own immunogenicity and antigen presentation. Ezh2 inactivation reversed this resistance and synergized with anti-CTLA-4 and IL-2 immunotherapy to suppress melanoma growth. These anti-tumor effects depended on intratumorally accumulating interferon-γ (IFN-γ)-producing PD-1low CD8+ T cells and PD-L1 downregulation on melanoma cells. Hence, Ezh2 serves as a molecular switch controlling melanoma escape during T cell-targeting immunotherapies.


Assuntos
Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Linfócitos T/metabolismo , Animais , Western Blotting , Antígeno CTLA-4/metabolismo , Linhagem Celular , Imunoprecipitação da Cromatina , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Imunofluorescência , Humanos , Imunoterapia , Interleucina-2/metabolismo , Melanoma/metabolismo , Melanoma/terapia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Fator de Necrose Tumoral alfa/metabolismo
12.
Sci Transl Med ; 8(367): 367ra166, 2016 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-27903862

RESUMO

Interleukin-2 (IL-2) immunotherapy is an attractive approach in treating advanced cancer. However, by binding to its IL-2 receptor α (CD25) subunit, IL-2 exerts unwanted effects, including stimulation of immunosuppressive regulatory T cells (Tregs) and contribution to vascular leak syndrome. We used a rational approach to develop a monoclonal antibody to human IL-2, termed NARA1, which acts as a high-affinity CD25 mimic, thereby minimizing association of IL-2 with CD25. The structure of the IL-2-NARA1 complex revealed that NARA1 occupies the CD25 epitope of IL-2 and precisely overlaps with CD25. Association of NARA1 with IL-2 occurs with 10-fold higher affinity compared to CD25 and forms IL-2/NARA1 complexes, which, in vivo, preferentially stimulate CD8+ T cells while disfavoring CD25+ Tregs and improving the benefit-to-adverse effect ratio of IL-2. In two transplantable and one spontaneous metastatic melanoma model, IL-2/NARA1 complex immunotherapy resulted in efficient expansion of tumor-specific and polyclonal CD8+ T cells. These CD8+ T cells showed robust interferon-γ production and expressed low levels of exhaustion markers programmed cell death protein-1, lymphocyte activation gene-3, and T cell immunoglobulin and mucin domain-3. These effects resulted in potent anticancer immune responses and prolonged survival in the tumor models. Collectively, our data demonstrate that NARA1 acts as a CD25-mimobody that confers selectivity and increased potency to IL-2 and warrant further assessment of NARA1 as a therapeutic.


Assuntos
Anticorpos Monoclonais/química , Imunoterapia/métodos , Subunidade alfa de Receptor de Interleucina-2/imunologia , Interleucina-2/antagonistas & inibidores , Neoplasias/terapia , Animais , Sítios de Ligação , Linfócitos T CD8-Positivos/citologia , Proliferação de Células , Epitopos/química , Inativação Gênica , Humanos , Melanoma Experimental/imunologia , Melanoma Experimental/terapia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neoplasias/imunologia , Conformação Proteica , Recombinação Genética , Linfócitos T Citotóxicos/citologia , Linfócitos T Reguladores/imunologia
13.
Genome Biol ; 16: 42, 2015 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-25885555

RESUMO

BACKGROUND: Melanoma is the most fatal skin cancer displaying a high degree of molecular heterogeneity. Phenotype switching is a mechanism that contributes to melanoma heterogeneity by altering transcription profiles for the transition between states of proliferation/differentiation and invasion/stemness. As phenotype switching is reversible, epigenetic mechanisms, like DNA methylation, could contribute to the changes in gene expression. RESULTS: Integrative analysis of methylation and gene expression datasets of five proliferative and five invasion melanoma cell cultures reveal two distinct clusters. SOX9 is methylated and lowly expressed in the highly proliferative group. SOX9 overexpression results in decreased proliferation but increased invasion in vitro. In a B16 mouse model, sox9 overexpression increases the number of lung metastases. Transcriptional analysis of SOX9-overexpressing melanoma cells reveals enrichment in epithelial to mesenchymal transition (EMT) pathways. Survival analysis of The Cancer Genome Atlas melanoma dataset shows that metastatic patients with high expression levels of SOX9 have significantly worse survival rates. Additional survival analysis on the targets of SOX9 reveals that most SOX9 downregulated genes have survival benefit for metastatic patients. CONCLUSIONS: Our genome-wide DNA methylation and gene expression study of 10 early passage melanoma cell cultures reveals two phenotypically distinct groups. One of the genes regulated by DNA methylation between the two groups is SOX9. SOX9 induces melanoma cell invasion and metastasis and decreases patient survival. A number of genes downregulated by SOX9 have a negative impact on patient survival. In conclusion, SOX9 is an important gene involved in melanoma invasion and negatively impacts melanoma patient survival.


Assuntos
Melanoma/genética , Invasividade Neoplásica/genética , Fatores de Transcrição SOX9/biossíntese , Neoplasias Cutâneas/genética , Idoso , Animais , Linhagem Celular Tumoral , Proliferação de Células/genética , Metilação de DNA/genética , Transição Epitelial-Mesenquimal/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Melanoma/patologia , Camundongos , Pessoa de Meia-Idade , Invasividade Neoplásica/patologia , Estadiamento de Neoplasias , Prognóstico , Fatores de Transcrição SOX9/genética , Transdução de Sinais , Neoplasias Cutâneas/patologia , Análise de Sobrevida
14.
Nat Commun ; 6: 6051, 2015 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-25609585

RESUMO

Increased activity of the epigenetic modifier EZH2 has been associated with different cancers. However, evidence for a functional role of EZH2 in tumorigenesis in vivo remains poor, in particular in metastasizing solid cancers. Here we reveal central roles of EZH2 in promoting growth and metastasis of cutaneous melanoma. In a melanoma mouse model, conditional Ezh2 ablation as much as treatment with the preclinical EZH2 inhibitor GSK503 stabilizes the disease through inhibition of growth and virtually abolishes metastases formation without affecting normal melanocyte biology. Comparably, in human melanoma cells, EZH2 inactivation impairs proliferation and invasiveness, accompanied by re-expression of tumour suppressors connected to increased patient survival. These EZH2 target genes suppress either melanoma growth or metastasis in vivo, revealing the dual function of EZH2 in promoting tumour progression. Thus, EZH2-mediated epigenetic repression is highly relevant especially during advanced melanoma progression, which makes EZH2 a promising target for novel melanoma therapies.


Assuntos
Inativação Gênica , Melanoma/metabolismo , Complexo Repressor Polycomb 2/fisiologia , Neoplasias Cutâneas/metabolismo , Adenosilmetionina Descarboxilase/metabolismo , Animais , Proliferação de Células , Proteína Potenciadora do Homólogo 2 de Zeste , Epigênese Genética , Transição Epitelial-Mesenquimal , Feminino , Regulação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Genótipo , Homeostase , Humanos , Melanócitos/metabolismo , Melanoma Experimental/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Invasividade Neoplásica , Metástase Neoplásica , Complexo Repressor Polycomb 2/genética , Resultado do Tratamento , Melanoma Maligno Cutâneo
15.
PLoS Genet ; 11(1): e1004877, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25629959

RESUMO

Melanoma is the most fatal skin cancer, but the etiology of this devastating disease is still poorly understood. Recently, the transcription factor Sox10 has been shown to promote both melanoma initiation and progression. Reducing SOX10 expression levels in human melanoma cells and in a genetic melanoma mouse model, efficiently abolishes tumorigenesis by inducing cell cycle exit and apoptosis. Here, we show that this anti-tumorigenic effect functionally involves SOX9, a factor related to SOX10 and upregulated in melanoma cells upon loss of SOX10. Unlike SOX10, SOX9 is not required for normal melanocyte stem cell function, the formation of hyperplastic lesions, and melanoma initiation. To the contrary, SOX9 overexpression results in cell cycle arrest, apoptosis, and a gene expression profile shared by melanoma cells with reduced SOX10 expression. Moreover, SOX9 binds to the SOX10 promoter and induces downregulation of SOX10 expression, revealing a feedback loop reinforcing the SOX10 low/SOX9 high ant,m/ii-tumorigenic program. Finally, SOX9 is required in vitro and in vivo for the anti-tumorigenic effect achieved by reducing SOX10 expression. Thus, SOX10 and SOX9 are functionally antagonistic regulators of melanoma development.


Assuntos
Carcinogênese/genética , Melanoma/genética , Fatores de Transcrição SOX9/genética , Fatores de Transcrição SOXE/genética , Animais , Apoptose/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Folículo Piloso , Humanos , Melanócitos/patologia , Melanoma/patologia , Camundongos , RNA Interferente Pequeno , Fatores de Transcrição SOX9/biossíntese , Fatores de Transcrição SOXE/biossíntese
16.
Nat Cell Biol ; 14(8): 882-90, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22772081

RESUMO

Giant congenital naevi are pigmented childhood lesions that frequently lead to melanoma, the most aggressive skin cancer. The mechanisms underlying this malignancy are largely unknown, and there are no effective therapies. Here we describe a mouse model for giant congenital naevi and show that naevi and melanoma prominently express Sox10, a transcription factor crucial for the formation of melanocytes from the neural crest. Strikingly, Sox10 haploinsufficiency counteracts Nras(Q61K)-driven congenital naevus and melanoma formation without affecting the physiological functions of neural crest derivatives in the skin. Moreover, Sox10 is also crucial for the maintenance of neoplastic cells in vivo. In human patients, virtually all congenital naevi and melanomas are SOX10 positive. Furthermore, SOX10 silencing in human melanoma cells suppresses neural crest stem cell properties, counteracts proliferation and cell survival, and completely abolishes in vivo tumour formation. Thus, SOX10 represents a promising target for the treatment of congenital naevi and melanoma in human patients.


Assuntos
Melanoma/fisiopatologia , Nevo/patologia , Fatores de Transcrição SOXE/metabolismo , Animais , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Western Blotting , Linhagem Celular , Linhagem Celular Tumoral , Criança , Modelos Animais de Doenças , Feminino , Regulação Neoplásica da Expressão Gênica , Haploinsuficiência , Humanos , Imuno-Histoquímica , Lactente , Masculino , Melanoma/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Análise em Microsséries , Nevo/fisiopatologia , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição SOXE/genética
17.
J Bacteriol ; 193(6): 1449-60, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21239582

RESUMO

Sulfur is an essential nutrient that can exist at growth-limiting concentrations in freshwater environments. The freshwater cyanobacterium Fremyella diplosiphon (also known as Tolypothrix sp. PCC 7601) is capable of remodeling the composition of its light-harvesting antennae, or phycobilisomes, in response to changes in the sulfur levels in its environment. Depletion of sulfur causes these cells to cease the accumulation of two forms of a major phycobilisome protein called phycocyanin and initiate the production of a third form of phycocyanin, which possesses a minimal number of sulfur-containing amino acids. Since phycobilisomes make up approximately 50% of the total protein in these cells, this elemental sparing response has the potential to significantly influence the fitness of this species under low-sulfur conditions. This response is specific for sulfate and occurs over the physiological range of sulfate concentrations likely to be encountered by this organism in its natural environment. F. diplosiphon has two separate sulfur deprivation responses, with low sulfate levels activating the phycobilisome remodeling response and low sulfur levels activating the chlorosis or bleaching response. The phycobilisome remodeling response results from changes in RNA abundance that are regulated at both the transcriptional and posttranscriptional levels. The potential of this response, and the more general bleaching response of cyanobacteria, to provide sulfur-containing amino acids during periods of sulfur deprivation is examined.


Assuntos
Cianobactérias/genética , Cianobactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Sulfatos/metabolismo , Transcrição Gênica , Ficobilissomas/metabolismo , Ficocianina/metabolismo , Estabilidade de RNA , RNA Bacteriano/metabolismo , RNA Mensageiro/metabolismo
18.
Immunobiology ; 212(9-10): 693-9, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18086371

RESUMO

Circulating myeloid cells such as plasmacytoid dendritic cells (pDC), blood DC and monocytes act as blood sentinels detecting invading pathogens through a large repertoire of expression of toll-like receptors (TLRs). Activation of these receptors is crucial to detect invading pathogens by the innate immune system. In the present work, we analysed the TLR responsiveness of fibrocytes, a blood-derived cell type of myeloid origin. Fibrocytes efficiently responded to TLR2, TLR4, and TLR7 ligands as well as to poly (I:C) or viral stimulation by producing high amount of interleukin-6. Upon virus infection of fibrocytes, IFN type I was also induced. When compared to pDC or Flt3 ligand-derived DC, fibrocytes produced 5 times and 60 times more IL-6, respectively. This response was associated with a rapid and efficient translocation of the NF-kappaB transcription factor. Analysis of the expression and functionality of TLR7 in peripheral blood leukocyte subpopulations suggested that this receptor is expressed and functional in a CD163(+) monocytic cell subpopulation containing the fibrocyte precursors. Considering the rapid entry of fibrocytes into wounds, this efficient responsiveness to TLR danger signals, reflects a potentially important role of these cells in the first line of defence against pathogen invasion following traumata.


Assuntos
Citocinas/metabolismo , Células Dendríticas/metabolismo , Monócitos/metabolismo , NF-kappa B/metabolismo , Receptores Toll-Like/metabolismo , Antígenos CD/imunologia , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/imunologia , Antígenos de Diferenciação Mielomonocítica/metabolismo , Células Cultivadas , Citocinas/imunologia , Células Dendríticas/imunologia , Humanos , Indutores de Interferon/farmacologia , Interferon-alfa/biossíntese , Interferon-alfa/imunologia , Interleucina-6/biossíntese , Interleucina-6/imunologia , Monócitos/imunologia , NF-kappa B/imunologia , Poli I-C/farmacologia , Receptores de Superfície Celular/imunologia , Receptores de Superfície Celular/metabolismo , Transdução de Sinais
19.
Cancer Res ; 64(15): 5398-406, 2004 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-15289348

RESUMO

Ionizing radiation induces an intracellular stress response via activation of the phosphatidylinositol 3'-kinase (PI3K)/Akt survival pathway. In tumor cells, the PI3K/Akt pathway is induced through activation of members of ErbB receptor tyrosine kinases. Here, we investigated the receptor dependence of radiation-induced PI3K/Akt activation in tumor cells and in endothelial cells. The integrity of both the ErbB and the vascular endothelial growth factor (VEGF) ligand-activated PI3K/Akt pathway in endothelial cells was demonstrated using specific ErbB and VEGF receptor tyrosine kinase inhibitors. Irradiation of endothelial cells resulted in protein kinase B (PKB)/Akt activation in a similar time course as observed in response to VEGF. More importantly, radiation-induced PKB/Akt phosphorylation in endothelial cells was strongly down-regulated by the VEGF receptor tyrosine kinase inhibitor, whereas the ErbB receptor tyrosine kinase inhibitor did not affect PKB/Akt stimulation in response to irradiation. An opposite receptor dependence for radiation-induced PKB/Akt phosphorylation was observed in ErbB receptor-overexpressing A431 tumor cells. Furthermore, direct VEGF receptor phosphorylation was detected after irradiation in endothelial cells in absence of VEGF, which was almost completely inhibited after irradiation in presence of the VEGF receptor tyrosine kinase inhibitor. These data demonstrate that ionizing radiation induces VEGF ligand-independent but VEGF receptor-dependent PKB/Akt activation in endothelial cells and that PI3K/Akt pathway activation by radiation occurs in a differential cell type and receptor-dependent pattern.


Assuntos
Sobrevivência Celular/efeitos da radiação , Células Endoteliais/efeitos da radiação , Ativação Enzimática/efeitos da radiação , Neoplasias Pulmonares/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Transdução de Sinais/efeitos da radiação , Células Cultivadas , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Inibidores Enzimáticos/farmacologia , Humanos , Neoplasias Pulmonares/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt , Radiação Ionizante , Receptor ErbB-2/antagonistas & inibidores , Receptor ErbB-2/metabolismo , Receptores de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Receptores de Fatores de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/farmacologia
20.
Oncogene ; 23(26): 4624-35, 2004 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-15064712

RESUMO

An intact VEGF receptor/PI3K/PKB/Akt signaling cascade protects endothelial cells from apoptotic stress-stimuli and mediates the formation of new blood vessels in pathological conditions such as cancer. Therefore, downregulation of this signaling cascade is of clinical interest for antiangiogenic cancer therapy. In this report, we demonstrate that VEGF controls the protein stability of the serine-threonine kinase PKB/Akt via inhibition of PKB/Akt protein degradation. VEGF deprivation or blockage of the VEGF signal transduction cascade with the VEGF receptor tyrosine kinase inhibitor PTK787/ZK222584 resulted in a specific decrease of the PKB/Akt protein level and subsequent cellular restimulation with VEGF rescued its stability. Real-time quantitative RT-PCR analysis demonstrated that VEGF does not regulate PKB/Akt gene expression. On the other hand, broad range inhibitors of caspases and the proteasome complex prevented VEGF-dependent downregulation of the PKB/Akt protein level indicating that PKB/Akt protein stability is regulated by VEGF-controlled proteolysis. Inhibition of the VEGF receptor and PKB/Akt-downstream PIK-related mTOR-kinase by rapamycin also neutralized the VEGF-protective effect in an PKB/Akt gene expression-independent way but results in proteolysis-dependent reduction of PKB/Akt protein stability. These results demonstrate a novel regulatory mechanism of the activated VEGF receptor/mTOR-signal transduction pathway to control the protein stability of PKB/Akt and survival threshold in endothelial cells.


Assuntos
Endotélio Vascular/metabolismo , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas/metabolismo , Receptores de Fatores de Crescimento do Endotélio Vascular/metabolismo , Inibidores de Caspase , Caspases/metabolismo , Morte Celular/genética , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Células Cultivadas , Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Estabilidade Enzimática , Complexos Multienzimáticos/antagonistas & inibidores , Complexos Multienzimáticos/metabolismo , Ftalazinas/farmacologia , Complexo de Endopeptidases do Proteassoma , Proteínas Quinases/efeitos dos fármacos , Proteínas Proto-Oncogênicas/efeitos dos fármacos , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-akt , Piridinas/farmacologia , Transdução de Sinais , Sirolimo/farmacologia , Serina-Treonina Quinases TOR , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/farmacologia
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