RESUMO
OBJECTIVE: Chromatin texture patterns of tumour cell nuclei can serve as cancer biomarkers, either to define diagnostic classifications or to obtain relevant prognostic information, in a large number of human tumours. Epigenetic mechanisms, mainly DNA methylation and histone post-translational modification, have been shown to influence chromatin packing states, and therefore nuclear texture. The aim of this study was to analyse effects of these two mechanisms on chromatin texture, and also on correlation with gelatinase expression, in human fibrosarcoma tumour cells. MATERIALS AND METHODS: We investigated effects of DNA hypomethylating agent 5-aza-2'-deoxycytidine (5-azadC) and histone deacetylase inhibitor trichostatin A (TSA) on nuclear textural characteristics of human HT1080 fibrosarcoma cells, evaluated by image cytometry, and expression of gelatinases MMP-2 and MMP-9, two metalloproteinases implicated in cancer progression and metastasis. RESULTS: 5-azadC induced significant variation in chromatin higher order organization, particularly chromatin decondensation, associated with reduction in global DNA methylation, concomitantly with increase in MMP-9, and to a lesser extent, MMP-2 expression. TSA alone did not have any effect on HT1080 cells, but exhibited differential activity when added to cells treated with 5-azadC. When treated with both drugs, nuclei had higher texture abnormalities. In this setting, reduction in MMP-9 expression was observed, whereas MMP-2 expression remained unaffected. CONCLUSIONS: These data show that hypomethylating drug 5-azadC and histone deacetylase inhibitor TSA were able to induce modulation of higher order chromatin organization and gelatinase expression in human HT1080 fibrosarcoma cells.
Assuntos
Núcleo Celular/genética , Epigênese Genética , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/enzimologia , Cromatina/genética , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , Metilação de DNA , Decitabina , Progressão da Doença , Fibrossarcoma/enzimologia , Fibrossarcoma/patologia , Inibidores de Histona Desacetilases/farmacologia , Histonas/genética , Histonas/metabolismo , Humanos , Ácidos Hidroxâmicos/farmacologia , Citometria por Imagem , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 9 da Matriz/genética , Inibidores de Metaloproteinases de Matriz/farmacologia , Metástase Neoplásica/genética , Metástase Neoplásica/patologia , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismoRESUMO
Histone deacetylase enzymes (HDACs) are emerging as a promising biological target for cancer and inflammation. Using a fluorescence assay, we tested the in vitro HDAC inhibitory activity of twenty-one natural chalcones, a widespread group of natural products with well-known anti-inflammatory and antitumor effects. Since HDACs regulate the expression of the transcription factor NF-κB, we also evaluated the inhibitory potential of the compounds on NF-κB activation. Only four chalcones, isoliquiritigenin (no. 10), butein (no. 12), homobutein (no. 15) and the glycoside marein (no. 21) showed HDAC inhibitory activity with IC50 values of 60-190 µM, whereas a number of compounds inhibited TNFα-induced NF-κB activation with IC50 values in the range of 8-41 µM. Interestingly, three chalcones (nos. 10, 12 and 15) inhibited both TNFα-induced NF-κB activity and total HDAC activity of classes I, II and IV. Molecular modeling and docking studies were performed to shed light into dual activity and to draw structure-activity relationships among chalcones (nos. 1-21). To the best of our knowledge this is the first study that provides evidence for HDACs as potential drug targets for natural chalcones. The dual inhibitory potential of the selected chalcones on NF-κB and HDACs was investigated for the first time. This study demonstrates that chalcones can serve as lead compounds in the development of dual inhibitors against both targets in the treatment of inflammation and cancer.
Assuntos
Anti-Inflamatórios/farmacologia , Antineoplásicos/farmacologia , Chalconas/farmacologia , Inibidores de Histona Desacetilases/farmacologia , NF-kappa B/antagonistas & inibidores , Anti-Inflamatórios/química , Antineoplásicos/química , Domínio Catalítico , Linhagem Celular Tumoral , Chalconas/química , Simulação por Computador , Regulação da Expressão Gênica/efeitos dos fármacos , Genes Reporter , Inibidores de Histona Desacetilases/química , Histona Desacetilases/química , Histona Desacetilases/metabolismo , Humanos , Luciferases de Renilla/biossíntese , Luciferases de Renilla/genética , Modelos Moleculares , NF-kappa B/metabolismo , Ligação Proteica , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/química , Proteínas Repressoras/metabolismoAssuntos
Regulação Enzimológica da Expressão Gênica , Glutationa Transferase/genética , Isoenzimas/genética , Leucemia/enzimologia , Animais , Metilação de DNA , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glutationa S-Transferase pi , Humanos , Leucemia/genética , Regiões Promotoras Genéticas/genética , Ratos , Fator de Transcrição AP-1/farmacologia , Transcrição GênicaRESUMO
Curcumin presents strong antioxidant and anticancer properties. However, molecular mechanisms leading to curcumin-induced cell death are poorly understood. The effect of curcumin was compared in two different leukemia cell lines: K562 and Jurkat. Cell death was induced in both cell lines, and apoptosis pathways were investigated by Western blot analysis. Decreases in pro-caspase 8 and 9 levels were observed. BH(3) interacting domain death agonist (Bid) was also cleaved. Jurkat cells appeared to be more sensitive to curcumin, and apoptosis takes place earlier.
