RESUMO
Recent genome-wide association studies have revealed that variations near the gene locus encoding the transcription factor Krüppel-like factor 14 (KLF14) are strongly associated with HDL cholesterol (HDL-C) levels, metabolic syndrome, and coronary heart disease. However, the precise mechanisms by which KLF14 regulates lipid metabolism and affects atherosclerosis remain largely unexplored. Here, we report that KLF14 is dysregulated in the liver of 2 dyslipidemia mouse models. We evaluated the effects of both KLF14 overexpression and genetic inactivation and determined that KLF14 regulates plasma HDL-C levels and cholesterol efflux capacity by modulating hepatic ApoA-I production. Hepatic-specific Klf14 deletion in mice resulted in decreased circulating HDL-C levels. In an attempt to pharmacologically target KLF14 as an experimental therapeutic approach, we identified perhexiline, an approved therapeutic small molecule presently in clinical use to treat angina and heart failure, as a KLF14 activator. Indeed, in WT mice, treatment with perhexiline increased HDL-C levels and cholesterol efflux capacity via KLF14-mediated upregulation of ApoA-I expression. Moreover, perhexiline administration reduced atherosclerotic lesion development in apolipoprotein E-deficient mice. Together, these results provide comprehensive insight into the KLF14-dependent regulation of HDL-C and subsequent atherosclerosis and indicate that interventions that target the KLF14 pathway should be further explored for the treatment of atherosclerosis.
Assuntos
Apolipoproteína A-I/biossíntese , Aterosclerose/prevenção & controle , HDL-Colesterol/sangue , Colesterol/metabolismo , Hiperlipoproteinemia Tipo II/tratamento farmacológico , Fatores de Transcrição Kruppel-Like/fisiologia , Fígado/metabolismo , Perexilina/farmacologia , Animais , Apolipoproteína A-I/genética , Apolipoproteínas E/deficiência , Aterosclerose/etiologia , Aterosclerose/genética , Aterosclerose/terapia , Dieta Aterogênica , Avaliação Pré-Clínica de Medicamentos , Regulação da Expressão Gênica/efeitos dos fármacos , Terapia Genética , Vetores Genéticos/uso terapêutico , Estudo de Associação Genômica Ampla , Células Hep G2 , Humanos , Hiperlipoproteinemia Tipo II/metabolismo , Fatores de Transcrição Kruppel-Like/agonistas , Leptina/deficiência , Fígado/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Proteínas Recombinantes de Fusão/metabolismo , Fatores de Transcrição Sp/genética , Fatores de Transcrição Sp/metabolismo , Proteínas de Ligação a Elemento Regulador de Esterol/biossíntese , Proteínas de Ligação a Elemento Regulador de Esterol/genéticaRESUMO
Treatment of ErbB2-overexpressing BT474 and MDA-MB-453 breast cancer cells with 1 to 10 µmol/L betulinic acid inhibited cell growth, induced apoptosis, downregulated specificity protein (Sp) transcription factors Sp1, Sp3, and Sp4, and decreased expression of ErbB2. Individual or combined knockdown of Sp1, Sp3, Sp4 by RNA interference also decreased expression of ErbB2 and this response was because of repression of YY1, an Sp-regulated gene. Betulinic acid-dependent repression of Sp1, Sp3, Sp4, and Sp-regulated genes was due, in part, to induction of the Sp repressor ZBTB10 and downregulation of microRNA-27a (miR-27a), which constitutively inhibits ZBTB10 expression, and we show for the first time that the effects of betulinic acid on the miR-27a:ZBTB10-Sp transcription factor axis were cannabinoid 1 (CB1) and CB2 receptor-dependent, thus identifying a new cellular target for this anticancer agent.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , MicroRNAs/genética , Receptor ErbB-2/antagonistas & inibidores , Receptores de Canabinoides/metabolismo , Proteínas Repressoras/genética , Triterpenos/farmacologia , Fator de Transcrição YY1/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cricetinae , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , Triterpenos Pentacíclicos , Fatores de Transcrição Sp/genética , Fatores de Transcrição Sp/metabolismo , Ácido BetulínicoRESUMO
Curcumin activates diverse anticancer activities that lead to inhibition of cancer cell and tumor growth, induction of apoptosis, and antiangiogenic responses. In this study, we observed that curcumin inhibits Panc28 and L3.6pL pancreatic cancer cell and tumor growth in nude mice bearing L3.6pL cells as xenografts. In addition, curcumin decreased expression of p50 and p65 proteins and NFkappaB-dependent transactivation and also decreased Sp1, Sp3, and Sp4 transcription factors that are overexpressed in pancreatic cancer cells. Because both Sp transcription factors and NFkappaB regulate several common genes such as cyclin D1, survivin, and vascular endothelial growth factor that contribute to the cancer phenotype, we also investigated interactions between Sp and NFkappaB transcription factors. Results of Sp1, Sp3, and Sp4 knockdown by RNA interference demonstrate that both p50 and p65 are Sp-regulated genes and that inhibition of constitutive or tumor necrosis factor-induced NFkappaB by curcumin is dependent on down-regulation of Sp1, Sp3, and Sp4 proteins by this compound. Curcumin also decreased mitochondrial membrane potential and induced reactive oxygen species in pancreatic cancer cells, and this pathway is required for down-regulation of Sp proteins in these cells, demonstrating that the mitochondriotoxic effects of curcumin are important for its anticancer activities.
Assuntos
Curcumina/uso terapêutico , NF-kappa B/metabolismo , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Fatores de Transcrição Sp/metabolismo , Animais , Western Blotting , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Curcumina/farmacologia , Ciclina D1/genética , Ensaio de Desvio de Mobilidade Eletroforética , Eletrofisiologia , Feminino , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Peróxido de Hidrogênio/farmacologia , Imuno-Histoquímica , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Camundongos Nus , NF-kappa B/genética , Reação em Cadeia da Polimerase , RNA Interferente Pequeno , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição Sp/genética , Fator de Transcrição Sp1/genética , Fator de Transcrição Sp1/metabolismo , Fator de Transcrição Sp3/genética , Fator de Transcrição Sp3/metabolismo , Fator de Transcrição Sp4/genética , Fator de Necrose Tumoral alfa/farmacologia , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Curcumin is the active component of tumeric, and this polyphenolic compound has been extensively investigated as an anticancer drug that modulates multiple pathways and genes. In this study, 10 to 25 micromol/L curcumin inhibited 253JB-V and KU7 bladder cancer cell growth, and this was accompanied by induction of apoptosis and decreased expression of the proapoptotic protein survivin and the angiogenic proteins vascular endothelial growth factor (VEGF) and VEGF receptor 1 (VEGFR1). Because expression of survivin, VEGF, and VEGFR1 are dependent on specificity protein (Sp) transcription factors, we also investigated the effects of curcumin on Sp protein expression as an underlying mechanism for the apoptotic and antiangiogenic activity of this compound. The results show that curcumin induced proteasome-dependent down-regulation of Sp1, Sp3, and Sp4 in 253JB-V and KU7 cells. Moreover, using RNA interference with small inhibitory RNAs for Sp1, Sp3, and Sp4, we observed that curcumin-dependent inhibition of nuclear factor kappaB (NF-kappaB)-dependent genes, such as bcl-2, survivin, and cyclin D1, was also due, in part, to loss of Sp proteins. Curcumin also decreased bladder tumor growth in athymic nude mice bearing KU7 cells as xenografts and this was accompanied by decreased Sp1, Sp3, and Sp4 protein levels in tumors. These results show for the first time that one of the underlying mechanisms of action of curcumin as a cancer chemotherapeutic agent is due, in part, to decreased expression of Sp transcription factors in bladder cancer cells.