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
We induced sulfadiazine resistance in two sulfadiazine sensitive strains of Toxoplasma gondii, RH (Type I) and ME-49 (Type II) in vitro by using drug pressure. At first, sulfadiazine susceptibility of the two sensitive strains and two naturally resistant strains of T. gondii was evaluated on Vero cells using an enzyme-linked immunosorbent assay (ELISA). The IC(50) values of sulfadiazine were 77 µg/mL for RH, 51 µg/mL for ME-49 and higher than 1000 µg/mL for the two natural resistant strains. Secondly, induced resistance of the strains by gradually increase sulfadiazine concentration was verified by this test, which resulted IC(50) values at higher than 1000 µg/mL. In conclusion we developed in vitro two sulfadiazine resistant strains called RH-R(SDZ) and ME-49-R(SDZ). These strains resistant to sulfadiazine would be useful to characterize resistance mechanisms to sulfadiazine.
