RESUMO
Peroxisome proliferator-activated receptor-gamma (PPARγ) plays a critical role in lipid and glucose homeostasis. It is the target of many drug discovery studies, because of its role in various disease states including diabetes and cancer. Thiazolidinediones, a synthetic class of agents that work by activation of PPARγ, have been used extensively as insulin-sensitizers for the management of type 2 diabetes. In this study, a combination of QSAR and docking methods were utilised to perform virtual screening of more than 25 million compounds in the ZINC library. The QSAR model was developed using 1,517 compounds and it identified 42,378 potential PPARγ agonists from the ZINC library, and 10,000 of these were selected for docking with PPARγ based on their diversity. Several steps were used to refine the docking results, and finally 30 potentially highly active ligands were identified. Four compounds were subsequently tested for their in vitro activity, and one compound was found to have a K i values of <5 µM.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Descoberta de Drogas , PPAR gama/agonistas , Tiazolidinedionas/administração & dosagem , Sítios de Ligação , Diabetes Mellitus Tipo 2/patologia , Humanos , Ligantes , Modelos Moleculares , Simulação de Acoplamento Molecular , PPAR gama/química , Receptores Ativados por Proliferador de Peroxissomo/química , Ligação Proteica , Relação Quantitativa Estrutura-AtividadeRESUMO
Gastric cancer (GC) is a lethal malignancy and the second most common cause of cancer-related deaths. Although treatment options such as chemotherapy, radiotherapy, and surgery have led to a decline in the mortality rate due to GC, chemoresistance remains as one of the major causes for poor prognosis and high recurrence rate. In this study, we investigated the potential effects of isorhamnetin (IH), a 3'-O-methylated metabolite of quercetin on the peroxisome proliferator-activated receptor γ (PPAR-γ) signaling cascade using proteomics technology platform, GC cell lines, and xenograft mice model. We observed that IH exerted a strong antiproliferative effect and increased cytotoxicity in combination with chemotherapeutic drugs. IH also inhibited the migratory/invasive properties of GC cells, which could be reversed in the presence of PPAR-γ inhibitor. We found that IH increased PPAR-γ activity and modulated the expression of PPAR-γ regulated genes in GC cells. Also, the increase in PPAR-γ activity was reversed in the presence of PPAR-γ-specific inhibitor and a mutated PPAR-γ dominant negative plasmid, supporting our hypothesis that IH can act as a ligand of PPAR-γ. Using molecular docking analysis, we demonstrate that IH formed interactions with seven polar residues and six nonpolar residues within the ligand-binding pocket of PPAR-γ that are reported to be critical for its activity and could competitively bind to PPAR-γ. IH significantly increased the expression of PPAR-γ in tumor tissues obtained from xenograft model of GC. Overall, our findings clearly indicate that antitumor effects of IH may be mediated through modulation of the PPAR-γ activation pathway in GC.
Assuntos
Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , PPAR gama/metabolismo , Quercetina/análogos & derivados , Transdução de Sinais/efeitos dos fármacos , Neoplasias Gástricas/tratamento farmacológico , Anilidas/farmacologia , Animais , Antineoplásicos/farmacologia , Proteínas Reguladoras de Apoptose/metabolismo , Western Blotting , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Feminino , Humanos , Camundongos , Camundongos Nus , Invasividade Neoplásica , PPAR gama/antagonistas & inibidores , Ligação Proteica/efeitos dos fármacos , Proteômica , Quercetina/metabolismo , Quercetina/farmacologia , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Increasing evidence indicates that the interaction between the CXC chemokine receptor-4 (CXCR4) and its ligand CXCL12 is critical in the process of metastasis that accounts for more than 90% of cancer-related deaths. Thus, novel agents that can downregulate the CXCR4/CXCL12 axis have therapeutic potential in inhibiting cancer metastasis. METHODS: In this report, we investigated the potential of an agent, plumbagin (5-hydroxy-2-methyl-1, 4-naphthoquinone), for its ability to modulate CXCR4 expression and function in various tumor cells using Western blot analysis, DNA binding assay, transient transfection, real time PCR analysis, chromatin immunoprecipitation, and cellular migration and invasion assays. RESULTS: We found that plumbagin downregulated the expression of CXCR4 in breast cancer cells irrespective of their HER2 status. The decrease in CXCR4 expression induced by plumbagin was not cell type-specific as the inhibition also occurred in gastric, lung, renal, oral, and hepatocellular tumor cell lines. Neither proteasome inhibition nor lysosomal stabilization had any effect on plumbagin-induced decrease in CXCR4 expression. Detailed study of the underlying molecular mechanism(s) revealed that the regulation of the downregulation of CXCR4 was at the transcriptional level, as indicated by downregulation of mRNA expression, inhibition of NF-κB activation, and suppression of chromatin immunoprecipitation activity. In addition, using a virtual, predictive, functional proteomics-based tumor pathway platform, we tested the hypothesis that NF-κB inhibition by plumbagin causes the decrease in CXCR4 and other metastatic genes. Suppression of CXCR4 expression by plumbagin was found to correlate with the inhibition of CXCL12-induced migration and invasion of both breast and gastric cancer cells. CONCLUSIONS: Overall, our results indicate, for the first time, that plumbagin is a novel blocker of CXCR4 expression and thus has the potential to suppress metastasis of cancer.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Movimento Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Naftoquinonas/farmacologia , Receptores CXCR4/metabolismo , Neoplasias da Mama , Linhagem Celular Tumoral , Quimiocina CXCL12/farmacologia , Quimiocina CXCL12/fisiologia , Simulação por Computador , Regulação para Baixo , Feminino , Genes Reporter , Humanos , Luciferases/biossíntese , Luciferases/genética , Modelos Biológicos , NF-kappa B/genética , NF-kappa B/metabolismo , Invasividade Neoplásica , Ligação Proteica , Receptores CXCR4/genética , Neoplasias Gástricas , Transcrição Gênica/efeitos dos fármacosRESUMO
Increasing evidences indicate that CXCR4/CXCL12 signaling pathway plays a pivotal role in the process of distant site metastasis that accounts for more than 90% of prostate cancer related deaths in patients. Thus, novel drugs that can downregulate CXCR4/CXCL12 axis have a great potential in the treatment of metastatic prostate cancer. In this report, we tested an agent, ursolic acid (UA) for its ability to modulate CXCR4 expression in prostate cancer cell lines and inhibit metastasis in vivo in transgenic adenocarcinoma of mouse prostate (TRAMP) model. We observed that UA downregulated the expression of CXCR4 in prostate cancer cells irrespective of their HER2 status in a dose- and time-dependent manner. Neither proteasome inhibitor nor lysosomal stabilization had any effect on UA-induced decrease in CXCR4 expression. When investigated for the molecular mechanisms, it was observed that the downregulation of CXCR4 was due to transcriptional regulation as indicated by downregulation of mRNA expression, inhibition of NF-κB activation and modulation of chromatin immunoprecipitation activity. Suppression of CXCR4 expression by UA further correlated with the inhibition of CXCL12-induced migration and invasion in prostate cancer cells. Finally, we also found that UA treatment can inhibit metastasis of prostate cancer to distal organs, including lung and liver and suppress CXCR4 expression levels in the prostate tissues of TRAMP mice. Overall, our experimental findings suggest that UA exerts its antimetastatic effects through the suppression of CXCR4 expression in prostate cancer both in vitro and in vivo.
Assuntos
Adenocarcinoma/metabolismo , Antineoplásicos/farmacologia , Quimiocina CXCL12/metabolismo , Neoplasias da Próstata/metabolismo , Receptores CXCR4/metabolismo , Triterpenos/farmacologia , Adenocarcinoma/patologia , Animais , Movimento Celular/efeitos dos fármacos , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Transgênicos , NF-kappa B/metabolismo , Metástase Neoplásica/prevenção & controle , Neoplasias da Próstata/patologia , Complexo de Endopeptidases do Proteassoma , Transdução de Sinais/efeitos dos fármacos , Ácido UrsólicoRESUMO
Development of drug resistance to standard chemotherapy is a common phenomenon that leads to poor prognosis in patients. Thus, novel agents that can attenuate chemoresistance are urgently needed. Therefore, we analyzed whether isorhamnetin (IH), a 3'-O-methylated metabolite of quercetin, can enhance the potential efficacy of capecitabine in gastric cancer. The potential effect of IH on viability was analyzed by MTT assay, apoptosis by flow cytometric analysis, and NF-κB activation by DNA binding as well as Western blot assays. The in vivo effect of IH was also examined on the growth of subcutaneously implanted tumors in nude mice. IH inhibited the viability, potentiated the apoptotic effects of capecitabine, abrogated NF-κB activation, and suppressed the expression of various NF-κB regulated gene products in tumor cells. In a gastric cancer xenograft model, administration of IH alone (1 mg/kg body weight, i.p.) significantly suppressed the tumor growth alone as well as in combination with capecitabine. IH further reduced NF-κB activation and the expression of various proliferative and oncogenic biomarkers in tumor tissues. Overall, our results demonstrate that IH can significantly enhance the anti-tumor effects of capecitabine through the negative regulation of NF-κB regulated oncogenic genes.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , NF-kappa B/metabolismo , Transdução de Sinais/efeitos dos fármacos , Neoplasias Gástricas/tratamento farmacológico , Proteínas Angiogênicas/metabolismo , Animais , Apoptose/efeitos dos fármacos , Sítios de Ligação , Capecitabina , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , DNA/metabolismo , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Relação Dose-Resposta a Droga , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/análogos & derivados , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos Nus , Quercetina/administração & dosagem , Quercetina/análogos & derivados , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Fatores de Tempo , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Increasing evidence from epidemiological, preclinical and clinical studies suggests that dysregulated inflammatory response plays a pivotal role in a multitude of chronic ailments including cancer. The molecular mechanism(s) by which chronic inflammation drives cancer initiation and promotion include increased production of pro-inflammatory mediators, such as cytokines, chemokines, reactive oxygen intermediates, increased expression of oncogenes, COX-2 (cyclo-oxygenase-2), 5-LOX (5-lipoxygenase) and MMPs (matrix metalloproteinases), and pro-inflammatory transcription factors such as NF-κB (nuclear factor κB), STAT3 (signal transducer and activator of transcription 3), AP-1 (activator protein 1) and HIF-1α (hypoxia-inducible factor 1α) that mediate tumour cell proliferation, transformation, metastasis, survival, invasion, angiogenesis, chemoresistance and radioresistance. These inflammation-associated molecules are activated by a number of environmental and lifestyle-related factors including infectious agents, tobacco, stress, diet, obesity and alcohol, which together are thought to drive as much as 90% of all cancers. The present review will focus primarily on the role of various inflammatory intermediates responsible for tumour initiation and progression, and discuss in detail the critical link between inflammation and cancer.
Assuntos
Inflamação/metabolismo , Neoplasias/metabolismo , Araquidonato 5-Lipoxigenase/metabolismo , Quimiocinas/metabolismo , Doença Crônica , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Citocinas/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Mediadores da Inflamação , Estilo de Vida , Metaloproteinases da Matriz/metabolismo , NF-kappa B/metabolismo , Neoplasias/etiologia , Neoplasias/genética , Oncogenes , Fator de Transcrição STAT3/metabolismo , Fator de Transcrição AP-1/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
PURPOSE: Because of poor prognosis and development of resistance against chemotherapeutic drugs, the existing treatment modalities for gastric cancer are ineffective. Hence, novel agents that are safe and effective are urgently needed. Whether γ-tocotrienol can sensitize gastric cancer to capecitabine in vitro and in a xenograft mouse model was investigated. EXPERIMENTAL DESIGN: The effect of γ-tocotrienol on proliferation of gastric cancer cell lines was examined by mitochondrial dye uptake assay, apoptosis by esterase staining, NF-κB activation by DNA-binding assay, and gene expression by Western blotting. The effect of γ-tocotrienol on the growth and chemosensitization was also examined in subcutaneously implanted tumors in nude mice. RESULTS: γ-Tocotrienol inhibited the proliferation of various gastric cancer cell lines, potentiated the apoptotic effects of capecitabine, inhibited the constitutive activation of NF-κB, and suppressed the NF-κB-regulated expression of COX-2, cyclin D1, Bcl-2, CXCR4, VEGF, and matrix metalloproteinase-9 (MMP-9). In a xenograft model of human gastric cancer in nude mice, we found that administration of γ-tocotrienol alone (1 mg/kg body weight, intraperitoneally 3 times/wk) significantly suppressed the growth of the tumor and this effect was further enhanced by capecitabine. Both the markers of proliferation index Ki-67 and for microvessel density CD31 were downregulated in tumor tissue by the combination of capecitabine and γ-tocotrienol. As compared with vehicle control, γ-tocotrienol also suppressed the NF-κB activation and the expression of cyclin D1, COX-2, intercellular adhesion molecule-1 (ICAM-1), MMP-9, survivin, Bcl-xL, and XIAP. CONCLUSIONS: Overall our results show that γ-tocotrienol can potentiate the effects of capecitabine through suppression of NF-κB-regulated markers of proliferation, invasion, angiogenesis, and metastasis.
Assuntos
Cromanos/farmacologia , Desoxicitidina/análogos & derivados , Fluoruracila/análogos & derivados , NF-kappa B/metabolismo , Neoplasias Gástricas/tratamento farmacológico , Vitamina E/análogos & derivados , Animais , Protocolos de Quimioterapia Combinada Antineoplásica , Apoptose/efeitos dos fármacos , Capecitabina , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cromanos/metabolismo , Ciclina D1/biossíntese , Ciclo-Oxigenase 2/biossíntese , Desoxicitidina/farmacologia , Modelos Animais de Doenças , Fluoruracila/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Proteínas Inibidoras de Apoptose/biossíntese , Molécula 1 de Adesão Intercelular/biossíntese , Antígeno Ki-67/biossíntese , Metaloproteinase 9 da Matriz/biossíntese , Camundongos , Camundongos Nus , Mitocôndrias/metabolismo , Neovascularização Patológica/tratamento farmacológico , Molécula-1 de Adesão Celular Endotelial a Plaquetas/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Receptores CXCR4/biossíntese , Proteínas Repressoras/biossíntese , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Survivina , Fator A de Crescimento do Endotélio Vascular/biossíntese , Vitamina E/metabolismo , Vitamina E/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Proteína bcl-X/biossínteseRESUMO
Phytochemicals and their synthetic derivatives are making a significant contribution in modern drug discovery programs by targeting several human diseases, including cancer. Most of these natural compounds are often multitargeted in nature, which is generally a very desirable property for cancer therapy, as carcinomas typically involve dysregulation of multiple genes and associated cell-signaling pathways at various stages of initiation, progression and metastasis. Additionally, these natural agents generally have lower side-effects, are readily available and hence are cost effective. One such natural compound is zerumbone, a cyclic eleven-membered sesquiterpene, isolated from the tropical plant Zingiber zerumbet Smith that has attracted great attention recently for its potent anticancer activities in several tumor models. This review summarizes the data based on various in vitro and in vivo studies related to the effects of zerumbone on numerous pivotal molecular targets in cancer and its reported chemopreventive/therapeutic effects in different models of cancer.