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1.
Int J Oncol ; 45(6): 2267-77, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25340839

RESUMO

Leiomyosarcomas remain challenging tumors to manage and novel therapy strategies besides radiation and conventional chemotherapy are needed. Targeting angiogenesis by inhibition of vascular endothelial growth factor (VEGF) receptor tyrosine kinases (RTKs) of the tumor vasculature with small molecules is a promising new therapy. It has been shown recently that these receptors are not only expressed on tumor endothelium but also on tumor cells themselves. Thus, we investigated the expression of members of the VEGF receptor (VEGFR) family and corresponding growth factors in leiomyosarcoma tissue specimens and in the leiomyosarcoma cell lines SK-LMS-1 and SK-UT-1. We evaluated the influence of the VEGFR inhibitor PTK787/ZK222584 (PTK787) on cell growth, migration, apoptosis and phosphorylation of intracellular signalling molecules. In human leiomyosarcoma tissue specimens VEGFR­1/-2 and platelet-derived growth factor receptor (PDGFR-ß) were strongly expressed. Both leiomyosarcoma cell lines expressed VEGFR­1/-3 and PDGFR-ß but VEGFR-2 protein expression was positive only in SK-UT-1. SK-LMS-1 and SK-UT-1 cells secreted high and low amounts of VEGF-A, respectively, whereas PDGF-BB secretion was similar in both cell lines. Application of PTK787 led to partial inhibition of PDGF-BB-activated AKT/p90RSK and ERK1/2 signalling pathways. In contrast, protein phosphorylation was not affected by PTK787 in VEGF-A-treated cells. PTK787 turned out to inhibit cell migration even though no effects were observed upon stimulation with VEGF-A or PDGF-BB. In line, cell growth in leiomyosarcoma cell lines remained unchanged upon PTK787 treatment alone and with subsequent VEGF-A- or PDGF-BB-stimulation. However, VEGF-A, but not PDGF-BB-treated cells showed increased cell death upon PTK787 treatment. VEGFR family members are expressed in leiomyosarcomas in vivo and in vitro. Upon receptor stimulation, PTK787 is able to inhibit subsequent phosphorylation events and influences cell survival but not metabolic activity and migration. Thus, the inhibitor is possibly an additional option in the treatment of leiomyosarcomas.


Assuntos
Leiomiossarcoma/tratamento farmacológico , Neovascularização Patológica/genética , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/biossíntese , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/biossíntese , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/biossíntese , Inibidores da Angiogênese/administração & dosagem , Becaplermina , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana , Humanos , Leiomiossarcoma/genética , Leiomiossarcoma/patologia , Neovascularização Patológica/tratamento farmacológico , Ftalazinas/administração & dosagem , Inibidores de Proteínas Quinases/administração & dosagem , Proteínas Proto-Oncogênicas c-sis/administração & dosagem , Proteínas Proto-Oncogênicas c-sis/biossíntese , Piridinas/administração & dosagem , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Receptores Proteína Tirosina Quinases/genética , Transdução de Sinais/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/administração & dosagem , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/biossíntese , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores
2.
Int J Oncol ; 42(3): 1120-6, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23337910

RESUMO

Abnormal accumulation and activation of the recepteur d'origine nantais (RON) has been implicated in epithelial tumor carcinogenesis. In the present study, we examined the effect of epigallocatechin-3-gallate (EGCG), the major green tea catechin, on the induction of RON and tumor growth in human gastric cancer. EGCG inhibited phorbol 12-myristate 13-acetate (PMA)-induced RON expression and reduced RON transcriptional activity. However, (-)-epigalloca-techin (EGC), (-)-epicatechin gallate (ECG) and (-)­epicatechin (EC) did not affect RON expression. Experiments with deleted and site-directed mutagenesis of the RON promoter indicated that Egr-1 binding sites in the RON promoter may be the EGCG­response element acting as a cis-element in gastric cancer cells. EGCG also inhibited PMA-induced Egr-1 expression and DNA binding in a dose-dependent manner. Furthermore, gastric cancer cells pretreated with PMA showed markedly enhanced invasiveness, which was partially abrogated by EGCG and siRNA-targeted RON and Egr-1. EGCG significantly reduced tumor growth in an in vivo tumor model, whereas RON expression was downregulated. These results suggest that EGCG may exert at least part of its anticancer effect by controlling RON expression through suppression of Egr-1 activation.


Assuntos
Catequina/análogos & derivados , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Neoplasias Gástricas/metabolismo , Animais , Catequina/metabolismo , Catequina/farmacologia , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteína 1 de Resposta de Crescimento Precoce/antagonistas & inibidores , Proteína 1 de Resposta de Crescimento Precoce/genética , Ativação Enzimática , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Invasividade Neoplásica , Transplante de Neoplasias , Extratos Vegetais , Regiões Promotoras Genéticas , Interferência de RNA , RNA Interferente Pequeno , Receptores Proteína Tirosina Quinases/genética , Chá , Acetato de Tetradecanoilforbol/análogos & derivados , Acetato de Tetradecanoilforbol/farmacologia , Transcrição Gênica/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Neoplasia ; 14(10): 915-25, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23097626

RESUMO

The prognosis of patients suffering from pancreatic cancer is still poor and novel therapeutic options are urgently needed. Recently, the transcription factor signal transducer and activator of transcription 5b (STAT5b) was associated with tumor progression in human solid cancer. Hence, we assessed whether STAT5b might serve as an anticancer target in ductal pancreatic adenocarcinoma (DPAC). We found that nuclear expression of STAT5b can be detected in approximately 50% of DPAC. Blockade of STAT5b by stable shRNA-mediated knockdown showed no effects on tumor cell growth in vitro. However, inhibition of tumor cell motility was found even in response to stimulation with epidermal growth factor or interleukin-6. These findings were paralleled by a reduction of prometastatic and proangiogenic factors in vitro. Subsequent in vivo experiments revealed a strong growth inhibition on STAT5b blockade in subcutaneous and orthotopic models. These findings were paralleled by impaired tumor angiogenesis in vivo. In contrast to the subcutaneous model, the orthotopic model revealed a strong reduction of tumor cell proliferation that emphasizes the meaning of assessing targets in an appropriate microenvironment. Taken together, our results suggest that STAT5b might be a potential novel target for human DPAC.


Assuntos
Adenocarcinoma Mucinoso/secundário , Carcinoma Ductal Pancreático/secundário , Carcinoma Papilar/secundário , Neovascularização Patológica , Neoplasias Pancreáticas/patologia , Fator de Transcrição STAT5/metabolismo , Adenocarcinoma Mucinoso/irrigação sanguínea , Adenocarcinoma Mucinoso/metabolismo , Animais , Western Blotting , Carcinoma Ductal Pancreático/irrigação sanguínea , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Papilar/irrigação sanguínea , Carcinoma Papilar/metabolismo , Movimento Celular , Proliferação de Células , Humanos , Técnicas Imunoenzimáticas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Gradação de Tumores , Invasividade Neoplásica , Metástase Neoplásica , Estadiamento de Neoplasias , Neoplasias Pancreáticas/irrigação sanguínea , Neoplasias Pancreáticas/metabolismo , Fosforilação , RNA Interferente Pequeno/genética , Fator de Transcrição STAT5/antagonistas & inibidores , Fator de Transcrição STAT5/genética , Taxa de Sobrevida , Células Tumorais Cultivadas
4.
Anticancer Res ; 32(7): 2551-61, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22753713

RESUMO

AIM: To evaluate the impact of heat-shock protein 90 (HSP90) blockade by the novel inhibitor NVP-AUY922, on tumor growth and angiogenesis in pancreatic cancer. MATERIALS AND METHODS: Effects of NVP-AUY922 on signaling pathways were evaluated by western blotting. Cell motility of cancer cells, pericytes and endothelial cells was investigated in Boyden chambers. Impact of HSP90 blockade on pancreatic tumor growth and angiogenesis were studied in in vivo tumor models. RESULTS: NVP-AUY922 effectively inhibited cancer cell growth. Moreover, HSP90 inhibition potently interfered with multiple signaling pathways in cancer cells, as well as endothelial cells and pericytes, leading to significant reduction of pro-migratory and invasive properties of these cell types. In vivo, treatment with NVP-AUY922 significantly inhibited growth and vascularization of pancreatic cancer at doses far below the maximum tolerated dose. CONCLUSION: HSP90 blockade by the novel synthetic inhibitor NVP-AUY922 effectively reduces pancreatic cancer progression through direct effects on cancer cells, as well as on endothelial cells and pericytes.


Assuntos
Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Isoxazóis/farmacologia , Neoplasias Pancreáticas/irrigação sanguínea , Neoplasias Pancreáticas/tratamento farmacológico , Resorcinóis/farmacologia , Animais , Comunicação Celular/efeitos dos fármacos , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Terapia de Alvo Molecular , Neovascularização Patológica/tratamento farmacológico , Neoplasias Pancreáticas/patologia , Distribuição Aleatória , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Anticancer Res ; 32(2): 427-37, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22287729

RESUMO

AIM: To evaluate the effects of HSP90 blockade by EC154 on the oncogenic receptor tyrosine kinase macrophage-stimulating 1 receptor (MST1R) in gastric and pancreatic cancer. MATERIALS AND METHODS: Impact of EC154 on signaling pathways was investigated by western blotting. Cancer cell migration was evaluated in Boyden chambers. Transcriptional regulation of MST1R was examined by using promoter-luciferase reporter constructs. Effects on MST1R expression, and tumor growth were investigated in in vivo tumor models. RESULTS: MST1R was expressed by cancer cells without evidence of MST1R mutations. EC154 led to an effective inhibition of cancer cell growth, down-regulated MST1R, diminished its promoter activity, and disrupted oncogenic macrophage-stimulating protein 1 (MSP1) signaling. Moreover, pro-migratory activities of cancer cells were dramatically inhibited. In vivo, treatment with EC154 significantly reduced tumor growth, while MST1R expression was down-regulated. CONCLUSION: Wild-type MST1R is an HSP90 client protein that can be targeted in gastrointestinal cancer using HSP90 inhibitors.


Assuntos
Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/enzimologia , Receptores Proteína Tirosina Quinases/metabolismo , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/enzimologia , Animais , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Fator de Crescimento de Hepatócito/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Terapia de Alvo Molecular , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogênicas/metabolismo , Receptores Proteína Tirosina Quinases/biossíntese , Receptores Proteína Tirosina Quinases/genética , Transdução de Sinais/efeitos dos fármacos , Neoplasias Gástricas/genética
6.
Mol Cancer Ther ; 10(11): 2157-67, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21885862

RESUMO

Activation of receptor tyrosine kinases, such as fibroblast growth factor receptor (FGFR), platelet-derived growth factor receptor (PDGFR), and VEGF receptor (VEGFR), has been implicated in tumor progression and metastasis in human pancreatic cancer. In this study, we investigated the effects of TKI258, a tyrosine kinase inhibitor to FGFR, PDGFR, and VEGFR on pancreatic cancer cell lines (HPAF-II, BxPC-3, MiaPaCa2, and L3.6pl), endothelial cells, and vascular smooth muscle cells (VSMC). Results showed that treatment with TKI258 impaired activation of signaling intermediates in pancreatic cancer cells, endothelial cells, and VSMCs, even upon stimulation with FGF-1, FGF-2, VEGF-A, and PDGF-B. Furthermore, blockade of FGFR/PDGFR/VEGFR reduced survivin expression and improved activity of gemcitabine in MiaPaCa2 pancreatic cancer cells. In addition, motility of cancer cells, endothelial cells, and VSMCs was reduced upon treatment with TKI258. In vivo, therapy with TKI258 led to dose-dependent inhibition of subcutaneous (HPAF-II) and orthotopic (L3.6pl) tumor growth. Immunohistochemical analysis revealed effects on tumor cell proliferation [bromodeoxyuridine (BrdUrd)] and tumor vascularization (CD31). Moreover, lymph node metastases were significantly reduced in the orthotopic tumor model when treatment was initiated early with TKI258 (30 mg/kg/d). In established tumors, TKI258 (30 mg/kg/d) led to significant growth delay and improved survival in subcutaneous and orthotopic models, respectively. These data provide evidence that targeting FGFR/PDFGR/VEGFR with TKI258 may be effective in human pancreatic cancer and warrants further clinical evaluation.


Assuntos
Antineoplásicos/farmacologia , Neovascularização Patológica/metabolismo , Neoplasias Pancreáticas/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Receptores de Fatores de Crescimento de Fibroblastos/antagonistas & inibidores , Receptores do Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Receptores de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Metástase Neoplásica , Neovascularização Patológica/tratamento farmacológico , Neoplasias Pancreáticas/irrigação sanguínea , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Pericitos/efeitos dos fármacos , Pericitos/metabolismo , Inibidores de Proteínas Quinases/uso terapêutico , Receptores de Fatores de Crescimento de Fibroblastos/genética , Receptores do Fator de Crescimento Derivado de Plaquetas/genética , Receptores de Fatores de Crescimento do Endotélio Vascular/genética , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
8.
BMC Cancer ; 10: 668, 2010 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-21129190

RESUMO

BACKGROUND: Activating transcription factor-3 (ATF3) is involved in the complex process of cellular stress response. However, its exact role in cancer is discussed controversially because both tumor suppressive and oncogenic effects have been described. Here we followed-up on our previous observation that inhibition of Hsp90 may increase ATF3 expression and sought to determine the role of ATF3 in colon cancer. METHODS: Regulation of ATF3 was determined in cancer cells using signaling inhibitors and a heat-shock protein-90 (Hsp90) antagonist. Human HCT116 cancer cells were stably transfected with an ATF3-shRNA or a luciferase-shRNA expression plasmid and alterations in cell motility were assessed in migration assays. The impact of ATF3 down-regulation on cancer growth and metastasis were investigated in a subcutaneous tumor model, a model of hepatic tumor growth and in a model of peritoneal carcinomatosis. Human colon cancer tissues were analyzed for ATF3 expression. RESULTS: The results show that therapeutic Hsp90 inhibition substantially up-regulates the expression of ATF3 in various cancer cells, including colon, gastric and pancreatic cancer. This effect was evident both in vitro and in vivo. RNAi mediated knock-down of ATF3 in HCT116 colon cancer cells significantly increased cancer cell migration in vitro. Moreover, in xenogenic mouse models, ATF3 knock-down promoted subcutaneous tumor growth and hepatic metastasis, as well as peritoneal carcinomatosis. Importantly, ATF3 expression was lower in human colon cancer specimens, as compared to corresponding normal surrounding tissues, suggesting that ATF3 may represent a down-regulated tumor suppressor in colon cancer. CONCLUSION: In conclusion, ATF3 down-regulation in colon cancer promotes tumor growth and metastasis. Considering that blocking Hsp90 induces ATF3 expression, Hsp90 inhibition may represent a valid strategy to treat metastatic colon cancer by up-regulating this anti-metastatic transcription factor.


Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Antineoplásicos/farmacologia , Benzoquinonas/farmacologia , Neoplasias do Colo/tratamento farmacológico , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Lactamas Macrocíclicas/farmacologia , Neoplasias Hepáticas/prevenção & controle , Neoplasias Peritoneais/prevenção & controle , Fator 3 Ativador da Transcrição/genética , Animais , Movimento Celular/efeitos dos fármacos , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Células HCT116 , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/secundário , Masculino , Camundongos , Camundongos Nus , Invasividade Neoplásica , Neoplasias Peritoneais/genética , Neoplasias Peritoneais/metabolismo , Neoplasias Peritoneais/secundário , Interferência de RNA , Fatores de Tempo , Transfecção , Carga Tumoral/efeitos dos fármacos , Regulação para Cima
9.
Curr Cancer Drug Targets ; 10(8): 890-7, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20718699

RESUMO

The inhibition of oncogenic signaling pathways has gained great interest for cancer therapy. In this context, the molecular chaperone heat shock protein 90 (HSP90) has emerged as a promising molecular target, since it is critically involved in maintaining stability, integrity and functions of key oncogenic proteins. A variety of HSP90 inhibitors have been developed in the past decade and have shown convincing anti-neoplastic activity in pre-clinical tumor models. Importantly, HSP90 inhibitors are predominantly being recognized as "tumor cell targeting" agents since cancer cells a) overexpress HSP90 protein, b) highly rely on HSP90 function for maintaining oncogenic signaling, and c) HSP90 inhibitors bind with high affinity to HSP90 in tumor cells. Nevertheless, results from recent studies also suggest that HSP90 inhibitors elicit anti-angiogenic properties by affecting the PI-3K/Akt/eNOS signal transduction pathway in endothelial cells, as well as through down-regulation of VEGFR-2 expression, a crucial component of the angiogenic process. In addition, blocking HSP90 may also diminish the secretion and expression of tumor cell-derived pro-angiogenic growth factors and cytokines, thus leading to "indirect" anti-angiogenic effects. This review article focuses on the role of HSP90 in angiogenesis and on delineating the effects of HSP90 inhibitors on angiogenic signaling pathways involved in tumor vascularization.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Neoplasias/irrigação sanguínea , Neovascularização Patológica/tratamento farmacológico , Humanos , Neoplasias/metabolismo
10.
Int J Clin Exp Med ; 3(2): 169-79, 2010 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-20607043

RESUMO

Hepatocellular carcinoma (HCC) belongs to the most frequent tumors worldwide with an incidence still rising. Patients with cirrhosis are at the highest risk for cancerogenesis and are candidates for surveillance, and here, as well as for the choice of potential forms of treatment, identification of suitable parameters for estimating the prognosis is of high clinical importance. The aim of this study was to describe the etiology of underlying liver disease and to identify predictors of survival in a large single center cohort of HCC patients in Southern Germany. Clinicopathologi-cal characteristics and survival rates of 458 patients (83.6% male; mean age: 62.5+/-11.2 years) consecutively admitted to a University Hospital between 1994 and 2008 were retrospectively analyzed. The results indicate that chronic alcohol abuse was the most common risk factor (57.2%), followed by infection with hepatitis B and C viruses (HBV: 10.9% and HCV: 20.5%). Overall median survival was 19.0 months, and higher OKUDA, CHILD and CLIP scores correlated negatively with prognosis. Of these, only the CLIP Score was an independent predictor in multivariate analysis. We conclude that chronic alcohol abuse is frequently associated with HCC in low hepatitis virus endemic areas, such as Germany. Our study suggests the CLIP score as a valuable prognostic marker for patients' survival, particularly of patients with alcohol related HCC.

12.
Biochim Biophys Acta ; 1803(4): 435-42, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20116405

RESUMO

Inhibition of mTORC1 with the mTOR inhibitor rapamycin may lead to an induction of Akt phosphorylation in cancer cells via mTORC2 activation. Using gastric and pancreatic cancer cells, we further investigated this paradoxical signaling response and found that rapamycin additionally up-regulates both IGF-IR and Her2 expression. Using RNAi for down-regulating RICTOR, this induction of receptor kinase expression was identified to be mediated via an mTORC2-induced Akt activation. Moreover, mTORC2 inhibition reduced the phosphorylation of GSK-3 and NF-kappaB, and significantly impaired cancer cell motility. In conclusion, inhibition of mTORC2 may abrogate unfavorable signaling effects of mTOR inhibitors, hence providing a novel rationale for therapy.


Assuntos
Proteínas de Transporte/metabolismo , Neoplasias Pancreáticas/metabolismo , Receptor ErbB-2/metabolismo , Receptor IGF Tipo 1/metabolismo , Neoplasias Gástricas/metabolismo , Fatores de Transcrição/fisiologia , Western Blotting , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Quinase 3 da Glicogênio Sintase/metabolismo , Humanos , NF-kappa B/metabolismo , Neoplasias Pancreáticas/patologia , Fosforilação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/farmacologia , Proteína Companheira de mTOR Insensível à Rapamicina , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Sirolimo/farmacologia , Neoplasias Gástricas/patologia
13.
Surgery ; 147(5): 704-12, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20015528

RESUMO

BACKGROUND: Targeting heat shock protein 90 (HSP90) has gained great interest for cancer therapy. However, in view of novel multimodality therapy approaches for treating hepatic metastases, concerns have raised regarding the impact of targeted therapies on liver regeneration and repair. In this study, we investigated the impact of HSP90 inhibition on liver regeneration in murine models. METHODS: Effects of HSP90 inhibition on the activation of signaling intermediates, expression of vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF) were investigated in primary human hepatocytes (PHHs) in vitro. Effects of HSP90 inhibition on liver regeneration and repair were determined in a murine hepatectomy model and in a model with acute carbon tetrachloride (CCl(4))-induced liver damage. RESULTS: Inhibition of HSP90 effectively diminished the constitutive phosphorylation of Akt, Erk, and STAT3 in PHHs. Conversely, inhibition of HSP90 significantly increased the expression of both VEGF and HGF mRNA, and induced HSP70 protein in PHH cultures in vitro. In vivo, HSP90 inhibition significantly upregulated constitutive VEGF mRNA and HSP70 in murine livers and did not impair liver re-growth after 70% hepatectomy. Furthermore, BrdUrd-staining and histological quantification of necrotic areas revealed that HSP90 inhibition did not impair liver regeneration following partial hepatectomy, or liver repair that occurs after toxic liver injury with CCl(4). CONCLUSION: Targeting HSP90 does not negatively affect the multifactorial process of liver regeneration and repair in vivo. Hence, the use of inhibitors to HSP90 appears to be a valid option for neoadjuvant therapy of liver metastases when subsequent surgery is intended.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Proteínas de Choque Térmico HSP90/farmacologia , Hepatócitos/efeitos dos fármacos , Regeneração Hepática/efeitos dos fármacos , Doença Aguda , Animais , Tetracloreto de Carbono/toxicidade , Células Cultivadas , Neoplasias Colorretais/patologia , Modelos Animais de Doenças , Hepatectomia , Fator de Crescimento de Hepatócito/metabolismo , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/secundário , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/metabolismo
14.
Langenbecks Arch Surg ; 395(2): 185-92, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19506898

RESUMO

PURPOSE: Treatment with DOTA-d-Phe(1)-Tyr(3)-octreotide (DOTATOC), labeled with beta-emitting radioisotope yttrium-90 ((90)Y-DOTATOC), has successfully been used for the palliative treatment of patients with advanced somatostatin receptor-expressing neuroendocrine tumors (NETs). However, controversy persists as to whether patients with metastatic NETs of the pancreas should undergo radical (salvage) surgery or receive palliative therapy. We proposed that (90)Y-DOTATOC could be used in a neoadjuvant intention for improving therapy of hepatic NET metastases. MATERIALS AND METHODS: We investigated a novel therapy concept in a 49-year-old patient presenting with a neuroendocrine tumor of the pancreatic tail and synchronous multiple bilobular hepatic metastases. After surgical removal of the large primary tumor by extended left en bloc resection of the pancreatic tail, the patient received neoadjuvant (90)Y-DOTATOC for therapy of primarily non-resectable bilobular hepatic metastases. RESULTS: The (90)Y-DOTATOC therapy resulted in an impressive regression of hepatic lesions, thus facilitating surgical removal of all remaining liver metastases in a second operation (staged surgery). In addition, one lesion was ablated using radiofrequency ablation (RFA). At 1-year of follow-up after hepatic R0 resection/RFA, there was no evidence of tumor recurrence or extrahepatic metastasis. CONCLUSIONS: The neoadjuvant use of (90)Y-DOTATOC therapy could prove valuable for treatment of advanced pancreatic NETs metastatic to the liver in terms of facilitating R0 resection by applying staged surgery concepts.


Assuntos
Neoplasias Hepáticas/terapia , Terapia Neoadjuvante/métodos , Tumores Neuroendócrinos/terapia , Octreotida/análogos & derivados , Pancreatectomia/métodos , Neoplasias Pancreáticas/patologia , Biópsia por Agulha , Ablação por Cateter , Hepatectomia/métodos , Humanos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/secundário , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tumores Neuroendócrinos/diagnóstico , Tumores Neuroendócrinos/secundário , Octreotida/uso terapêutico , Cuidados Paliativos , Tomografia por Emissão de Pósitrons , Indução de Remissão , Terapia de Salvação , Tomografia Computadorizada por Raios X , Resultado do Tratamento
15.
Mol Cancer Res ; 7(8): 1390-8, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19671674

RESUMO

Krüppel-like factor 5 (KLF5) is a transcription factor involved in cell transformation, proliferation, and carcinogenesis that can be up-regulated by RAS mutations. However, controversy persists as to whether it functions as a tumor suppressor or as an oncogene. Because KRAS is frequently mutated in pancreatic cancer, we investigated the regulation of KLF5 in this cancer entity. Our results show that KLF5 is overexpressed in pancreatic cancer cells and exceeds KLF5 expression of KRAS-mutated colon cancer cells. Surprisingly, inhibition of B-Raf/C-Raf or MAPK/Erk did not reduce KLF5 levels, suggesting that KLF5 expression is not promoted by KRAS-Raf-MEK-Erk signaling in pancreatic cancer. This finding is in striking contrast to reports on MEK-Erk-mediated KLF5 induction in colon cancer cells. Moreover, KLF5 expression levels neither correlated with the mutational status of KRAS nor with MEK phosphorylation in pancreatic cancer cells. Importantly, KLF5 was significantly up-regulated by interleukin (IL)-1beta or hypoxia. The IL-1 beta-mediated induction of KLF5 was diminished by blocking the p38 pathway. In addition, blocking IL-1R reduced the constitutive KLF5 expression, suggesting an autocrine activation loop. Moreover, KLF5 coimmunoprecipitated with hypoxia-inducible factor-1alpha (HIF-1alpha) and HIF-1alpha(siRNA) reduced constitutive KLF5. Similarly, KLF5(siRNA) reduced the expression of the HIF-1alpha target gene GLUT-1. Furthermore, KLF5 expression was significantly elevated by high cell density, by anchorage-independent cell growth, and in tumor spheroids. Down-regulation of KLF5 by RNAi reduced the expression of the target genes, survivin, and platelet-derived growth factor-A. In conclusion, overexpression of KLF5 in human pancreatic cancer cells is not mediated by KRAS/Raf/MAPK/Erk signaling, but involves the IL-1beta/IL-1R system, p38, and the transcription factor HIF-1alpha.


Assuntos
Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Interleucina-1beta/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Neoplasias Pancreáticas/genética , Transdução de Sinais , Regulação para Cima/genética , Contagem de Células , Hipóxia Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Interleucina-1beta/farmacologia , Fatores de Transcrição Kruppel-Like/metabolismo , Transdução de Sinais/efeitos dos fármacos , Esferoides Celulares/efeitos dos fármacos , Esferoides Celulares/metabolismo , Células Tumorais Cultivadas , Regulação para Cima/efeitos dos fármacos
16.
Anticancer Res ; 29(6): 2031-42, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19528462

RESUMO

Anticancer drug development strategies critically involve the identification of novel molecular targets which are crucial for tumorigenesis and metastasis. In this context, the molecular chaperone heat-shock protein 90 (Hsp90) has gained interest as a promising anticancer drug target, due to its importance in maintaining the stability, integrity, conformation and function of key oncogenic proteins. These Hsp90 "client proteins" have been demonstrated to play fundamental roles in the processes of signal transduction, cell proliferation and survival, cell cycle progression and apoptosis, as well as other features of malignant cells, such as invasion, tumor angiogenesis and metastasis. The cancer selectivity and antitumoral effects of Hsp90 inhibitors are mediated by simultaneous and combined actions, in terms of directly affecting multiple cancer targets and pathways. Several Hsp90 inhibitors, including the geldanamycin derivative 17-allylamino-17-demethoxygeldanamycin (17AAG), have displayed convincing antineoplastic efficacy and cancer selectivity in a variety of preclinical models, including gastrointestinal carcinomas. Importantly, some Hsp90 inhibitors have now progressed to phase I/II clinical testing. Against this background, the following review focuses on the current preclinical experience and value of targeting Hsp90 for the therapy of gastrointestinal carcinomas.


Assuntos
Benzoquinonas/uso terapêutico , Neoplasias Gastrointestinais/tratamento farmacológico , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Lactamas Macrocíclicas/uso terapêutico , Animais , Neoplasias Gastrointestinais/metabolismo , Neoplasias Gastrointestinais/patologia , Proteínas de Choque Térmico HSP90/metabolismo , Humanos
17.
Am J Pathol ; 174(4): 1544-52, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19286567

RESUMO

Accelerated glycolysis is one of the biochemical characteristics of cancer cells. The glucose transporter isoform 1 (GLUT1) gene encodes a key rate-limiting factor in glucose transport into cancer cells. However, its expression level and functional significance in hepatocellular cancer (HCC) are still disputed. Therefore, we aimed to analyze the expression and function of the GLUT1 gene in cases of HCC. We found significantly higher GLUT1 mRNA expression levels in HCC tissues and cell lines compared with primary human hepatocytes and matched nontumor tissue. Immunohistochemical analysis of a tissue microarray of 152 HCC cases revealed a significant correlation between Glut1 protein expression levels and a higher Ki-67 labeling index, advanced tumor stages, and poor differentiation. Accordingly, suppression of GLUT1 expression by siRNA significantly impaired both the growth and migratory potential of HCC cells. Furthermore, inhibition of GLUT1 expression reduced both glucose uptake and lactate secretion. Hypoxic conditions further increased GLUT1 expression levels in HCC cells, and this induction was dependent on the activation of the transcription factor hypoxia-inducible factor-1alpha. In summary, our findings suggest that increased GLUT1 expression levels in HCC cells functionally affect tumorigenicity, and thus, we propose GLUT1 as an innovative therapeutic target for this highly aggressive tumor.


Assuntos
Carcinoma Hepatocelular/metabolismo , Transportador de Glucose Tipo 1/biossíntese , Neoplasias Hepáticas/metabolismo , Western Blotting , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Hipóxia Celular/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica , Transportador de Glucose Tipo 1/genética , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Imuno-Histoquímica , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise Serial de Tecidos , Transfecção
18.
Hepatology ; 49(2): 523-32, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19085954

RESUMO

UNLABELLED: Hepatocellular carcinoma (HCC) remains associated with a poor prognosis, but novel targeted therapies in combination with anti-angiogenic substances may offer new perspectives. We hypothesized that simultaneous targeting of tumor cells, endothelial cells, and pericytes would reduce growth and angiogenesis of HCC, which represents a highly vascularized tumor entity. Recently, because of their anti-angiogenic properties, inhibitors of mammalian target of rapamycin (mTOR) have entered clinical trials for therapy of HCC. However, treatment with mTOR inhibitors may lead to paradoxical activation of Akt signaling in tumor cells via insulin-like growth factor-I receptor (IGF-IR)-dependent and IGF-IR-independent mechanisms. Because we have recently identified heat shock protein 90 (Hsp90) antagonists to impair both oncogenic and angiogenic signaling cascades in tumor cells, including Akt and IGF-IR, we sought to investigate whether Hsp90 blockade could improve growth-inhibitory and anti-angiogenic effects of the mTOR inhibitor rapamycin. Human HCC cells, a murine hepatoma cell line, endothelial cells (ECs), and vascular smooth muscle cells (VSMC) were employed in experiments. Results show that dual inhibition of mTOR and Hsp90 leads to effective disruption of oncogenic signaling cascades and substantially improves growth-inhibitory effects in vivo. Importantly, blocking Hsp90 abrogated the rapamycin-induced activation of Akt and of the downstream effector nuclear factor kappa-B (NF-kappaB) in HCC tumors. Furthermore, Hsp90 inhibition reduced the expression of platelet-derived growth factor-receptor-beta (PDGF-Rbeta) on VSMCs, and diminished vascular endothelial growth factor-receptor 2 (VEGFR-2) expression on ECs, which further improves the anti-angiogenic capacity of this regimen. CONCLUSION: Blocking Hsp90 disrupts rapamycin-induced activation of alternative signaling pathways in HCCs and substantially improves the growth-inhibitory effects of mTOR inhibition in vivo. Hence, the concept of targeting tumor cells, ECs, and VSMCs by blocking Hsp90/mTOR could prove valuable for treatment of HCC.


Assuntos
Antibióticos Antineoplásicos/uso terapêutico , Carcinoma Hepatocelular/tratamento farmacológico , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Neoplasias Hepáticas/tratamento farmacológico , Sirolimo/uso terapêutico , Animais , Carcinoma Hepatocelular/patologia , Proteínas de Transporte/antagonistas & inibidores , Morte Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Fragmentação do DNA , Primers do DNA , Modelos Animais de Doenças , Proteínas de Choque Térmico HSP90/genética , Humanos , Neoplasias Hepáticas/patologia , Camundongos , Fosfotransferases (Aceptor do Grupo Álcool)/antagonistas & inibidores , RNA Neoplásico/genética , RNA Neoplásico/isolamento & purificação , Serina-Treonina Quinases TOR , Fator A de Crescimento do Endotélio Vascular/genética
19.
Mol Cancer Ther ; 7(11): 3509-18, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19001434

RESUMO

The Ras/Raf/MEK pathway represents an important oncogenic signaling pathway in gastrointestinal malignancies, including pancreatic cancer. Although activating B-Raf mutations are infrequent in pancreatic cancer, we hypothesized that targeting Raf could be valuable for therapy of this cancer entity. Moreover, as vascular endothelial growth factor receptor 2 (VEGFR2) is involved in tumor angiogenesis, we sought to investigate the effects of dual inhibition of Raf and VEGFR2 on pancreatic tumor growth, vascularization, and metastasis. Effects of a Raf/VEGFR2 inhibitor (NVP-AAL881) on pancreatic cancer cells, endothelial cells, and vascular smooth muscle cells were determined by Western blotting, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide analysis, and migration assays, respectively. Changes in the expression of VEGF-A or survivin were investigated by ELISA and/or real-time PCR. The growth-inhibitory effects of Raf/VEGFR2 inhibition were additionally evaluated in orthotopic tumor models. Results showed that various Raf isoforms were activated in pancreatic cancer cells and NVP-AAL881 diminished the activation of MEK, Akt, Erk, and also STAT3. Moreover, dual inhibition of Raf/VEGFR2 significantly reduced VEGF expression and impaired cancer cell migration. Importantly, besides blocking VEGF-induced Erk and SAPK phosphorylation in endothelial cells, the Raf inhibitor diminished STAT3 phosphorylation, independent of a VEGFR2 blockade, and reduced the expression of survivin. In addition, cell proliferation and migration of both endothelial cells and vascular smooth muscle cells were significantly reduced. In vivo, blocking Raf/VEGFR2 significantly inhibited orthotopic tumor growth and vascularization and reduced cancer metastasis. In conclusion, blocking Raf exerts growth-inhibitory effects on pancreatic tumor cells, endothelial cells, and pericytes and elicits antiangiogenic properties. Dual targeting of Raf and VEGFR2 appears to be a valid strategy for therapy of pancreatic cancer.


Assuntos
Antineoplásicos/uso terapêutico , Células Endoteliais/efeitos dos fármacos , Isoquinolinas/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Pericitos/efeitos dos fármacos , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Quinases raf/antagonistas & inibidores , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Células Endoteliais/metabolismo , Humanos , Isoquinolinas/farmacologia , Masculino , Camundongos , Camundongos Nus , Metástase Neoplásica/patologia , Neovascularização Patológica/tratamento farmacológico , Neoplasias Pancreáticas/patologia , Pericitos/metabolismo , Transdução de Sinais , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Quinases raf/metabolismo
20.
BMC Cancer ; 8: 206, 2008 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-18651980

RESUMO

BACKGROUND: Hepatocellular carcinoma (HCC) represents a highly vascularized tumor entity and the process of angiogenesis is essential for the growth of HCC. Importantly, the pro-angiogenic transcription factors HIF-1alpha and STAT3 have been implicated in HCC progression, thus representing interesting targets for molecular targeted therapy. We hypothesized that therapeutic inhibition of HIF-1alpha could be achieved by using a novel tubulin-binding agent (ENMD-1198). ENMD-1198 is an analog of 2-methoxyestradiol (2ME2) with antiproliferative and antiangiogenic activity. METHODS: The human HCC cell lines HUH-7 and HepG2 were used for experiments. Effects of ENMD-1198 on constitutive and inducible (hypoxia, growth factors) activation of signaling cascades, including HIF-1alpha and STAT3, were investigated by Western blotting. Changes in VEGF expression were determined by real-time PCR. Effects of ENMD-1198 on cancer cell migration and invasion were evaluated in in vitro-assays. The growth-inhibitory effects of ENMD-1198 (200 mg/kg/day) were determined in a subcutaneous tumor model (HUH-7). RESULTS: ENMD-1198 inhibited the phosphorylation of MAPK/Erk, PI-3K/Akt and FAK. Moreover, activation of HIF-1alpha and STAT3 was dramatically reduced by ENMD-1198, which resulted in lower VEGF mRNA expression (P < 0.05). In addition, tumor cell migratory and invasive properties were significantly inhibited (P < 0.05, for both). In vivo, treatment with ENMD-1198 led to a significant reduction in tumor growth, tumor vascularization, and numbers of proliferating tumor cells (P < 0.05 for all). CONCLUSION: The novel microtubule destabilizing agent ENMD-1198 is suitable for inhibiting HIF-1alpha and STAT3 in human HCC cells and leads to reduced tumor growth and vascularization in vivo. Hence, inhibition of HIF-1alpha and STAT3 could prove valuable for therapy of hepatocellular carcinoma.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Estrenos/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Neovascularização Patológica/tratamento farmacológico , Moduladores de Tubulina/farmacologia , Inibidores da Angiogênese/farmacologia , Carcinoma Hepatocelular/sangue , Carcinoma Hepatocelular/irrigação sanguínea , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/irrigação sanguínea , Neoplasias Hepáticas/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Transcrição STAT3/antagonistas & inibidores , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Ativação Transcricional/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/biossíntese , Fator A de Crescimento do Endotélio Vascular/genética
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