RESUMO
Hypoxia-inducible factor 1 (HIF-1) plays an essential role in tumor angiogenesis and growth by regulating the transcription of several genes in response to hypoxic stress and changes in growth factors. This study was designed to investigate the effects of deguelin on tumor growth and angiogenesis, and the mechanisms underlying the antitumor activities of deguelin. We show here that orally administered deguelin inhibits tumor growth and blocks tumor angiogenesis in mice. Deguelin decreased expression of HIF-1alpha protein and its target genes, such as VEGF, in a subset of cancer cell lines, including H1299 lung cancer cells, and vascular endothelial cells in normoxic and hypoxic conditions. Overexpression of vascular endothelial growth factor by adenoviral vector infection abolished the antiangiogenic effects of deguelin on H1299 nonsmall cell lung cancer cells. Deguelin inhibited de novo synthesis of HIF-1alpha protein and reduced the half-life of the synthesized protein. MG132, a proteasome inhibitor, protected the hypoxia- or IGF-induced HIF-1alpha protein from deguelin-mediated degradation. Our findings suggest that deguelin is a promising antiangiogenic therapeutic agent in cancer targeting HIF-1alpha. Considering that HIF-1alpha is overexpressed in a majority of human cancers, deguelin could offer a potent therapeutic agent for cancer.
Assuntos
Inibidores da Angiogênese/farmacologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Neoplasias/irrigação sanguínea , Rotenona/análogos & derivados , Animais , Animais Geneticamente Modificados , Aorta/efeitos dos fármacos , Aorta/metabolismo , Western Blotting , Hipóxia Celular , Movimento Celular , Proliferação de Células/efeitos dos fármacos , Embrião de Galinha , Membrana Corioalantoide/efeitos dos fármacos , Membrana Corioalantoide/metabolismo , Membrana Corioalantoide/patologia , Colágeno/metabolismo , Meios de Cultivo Condicionados , Inibidores de Cisteína Proteinase/farmacologia , Combinação de Medicamentos , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Laminina/metabolismo , Leupeptinas/farmacologia , Luciferases/metabolismo , Camundongos , Neoplasias/metabolismo , Neoplasias/prevenção & controle , Neovascularização Patológica/patologia , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Proteoglicanas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Rotenona/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacos , Ubiquitina/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Peixe-ZebraRESUMO
Deguelin has shown promising chemopreventive and therapeutic activities in diverse types of cancers. However, the potential side effect of deguelin over a certain dose could be the substantial hurdle in the practical application of the drug. One of the successful strategies for the use of deguelin in clinical trials could be lung-specific delivery of the drug. The present study evaluates the efficacy of liposome-encapsulated deguelin with a dose of 0.4 mg/kg, which is 10 times less than the dose (4 mg/kg) for preventive and therapeutic activities validated in previous in vivo studies. Liposomal deguelin revealed cytotoxic activity in vitro in premalignant and malignant human bronchial epithelial cells and non-small cell lung cancer cells through the same mechanistic pathway previously reported for deguelin (i.e., suppression of the heat shock protein 90 chaperone function and induction of apoptosis). Delivery of liposomal deguelin at a dose of 0.4 mg/kg by intranasal instillation resulted in markedly increased drug partitioning to the lungs compared with that of 4 mg/kg deguelin or 0.4 mg/kg liposomal deguelin administered by oral gavage. Lung-specific delivery of deguelin (0.4 mg/kg) via nasal or intratracheal instillation in a liposomal formulation also showed significant chemopreventive and therapeutic activities in 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone/benzo(a)pyrene-treated A/J mice and K-rasLAC57Bl6/129/sv F1 mice with no detectable toxicity. Our findings support the potential use of deguelin in a liposomal formulation via lung-specific delivery to improve efficacy and to reduce the potential side effects of the agent.
Assuntos
Antineoplásicos/administração & dosagem , Antineoplásicos/farmacocinética , Neoplasias Pulmonares/tratamento farmacológico , Rotenona/análogos & derivados , Administração Intranasal , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Genes ras , Humanos , Imuno-Histoquímica , Lipossomos , Neoplasias Pulmonares/etiologia , Camundongos , Camundongos Mutantes , Lesões Pré-Cancerosas/tratamento farmacológico , Rotenona/administração & dosagem , Rotenona/farmacocinética , Distribuição TecidualRESUMO
Celecoxib is being evaluated as a chemopreventive agent. However, its mechanism of action is not clear because high doses were used for in vitro studies to obtain antitumor effects. We found that celecoxib inhibited the growth of premalignant and malignant human bronchial epithelial cells with IC(50) values between 8.9 and 32.7 micromol/L, irrespective of cyclooxygenase-2 (COX-2) expression. Normal human bronchial epithelial cells were less sensitive to celecoxib. Because these concentrations were higher than those attainable in vivo (Assuntos
Anticarcinógenos/farmacologia
, Apoptose/fisiologia
, Brônquios/efeitos dos fármacos
, Broncopatias/patologia
, Inibidores de Ciclo-Oxigenase 2/farmacologia
, Fenretinida/farmacologia
, Lesões Pré-Cancerosas/patologia
, Proteínas Proto-Oncogênicas c-akt/fisiologia
, Pirazóis/farmacologia
, Sulfonamidas/farmacologia
, Apoptose/efeitos dos fármacos
, Brônquios/citologia
, Celecoxib
, Linhagem Celular Tumoral/citologia
, Linhagem Celular Tumoral/efeitos dos fármacos
, Células Cultivadas/citologia
, Células Cultivadas/efeitos dos fármacos
, Ensaios de Seleção de Medicamentos Antitumorais
, Sinergismo Farmacológico
, Células Epiteliais/citologia
, Células Epiteliais/efeitos dos fármacos
, Humanos
, Neoplasias Pulmonares/patologia
, Neoplasias Pulmonares/prevenção & controle
, Mitocôndrias/fisiologia
, Fosforilação/efeitos dos fármacos
, Processamento de Proteína Pós-Traducional/efeitos dos fármacos
, Proteínas Proto-Oncogênicas c-akt/genética
, Proteínas Recombinantes de Fusão/genética
, Proteínas Recombinantes de Fusão/fisiologia
RESUMO
Tobacco carcinogens induce Akt activation and lung carcinogenesis. We previously demonstrated that deguelin, a natural plant product, specifically inhibits the proliferation of premalignant and malignant human bronchial epithelial cells by blocking Akt activation. To evaluate the ability of deguelin to block tobacco carcinogen-induced lung tumorigenesis, we evaluated the in vivo effects of deguelin on Akt activation and lung tumorigenesis in transgenic mice in which Akt expression was induced by tamoxifen and in 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK)/benzo(a)pyrene (BaP)-treated A/J mice. Deguelin suppressed Akt activation in vivo, as measured by immunohistochemistry and immunoblotting, and statistically significantly reduced NNK/BaP-induced lung tumor multiplicity, volume, and load in A/J mice, as monitored by microcomputed tomography image analysis, with no detectable toxicity. These results indicate that deguelin warrants consideration as a chemopreventive agent for early-stage lung carcinogenesis in a clinical lung cancer chemoprevention trial.