Avaliação in vitro do potencial citotóxico de quatro análogos de benzotiazóis

• Ano de defesa: 2011
• Autor(a) principal: Vieira, Gabriella Cunha
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Benzotiazóis; Apoptose
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/2354

Benzothiazole are compounds consisted of a benzene ring with a thiazole ring that present significant anticancer activity, especially the fenil substituted. Due to molecular modeling, a common method for drug design in medicinal chemistry and a useful technique for the development of new drugs, the substituted synthesis of Benzothiazole presented great advantage for the treatment of specific types of cancer. In the present study it was evaluated the cytotoxic potential of four of synthetic benzothiazole analogues with malignant and non malignant cell lines. The results demonstrated that all the tested analogues presented cytotoxic activity, however compound 1 (CI50 = 1,65µM) was chosen to give continuity to the assays because it is the prototype of the others, and compound 3 (CI50 = 1,01µM) was chosen due to its higher cytotoxicity compared to the others and for presenting a selectivity towards malignant cell line when compared to a non malignant cell line, peripheral mononuclear blood cells(PMBC). A series of assays was then carried out in vitro, where it aimed to clarify effects involved in this cytotoxic activity. The cell line HL60 was chosen to conduct the experiments for it was the most sensitive cell line to the exposure of compounds. In the viability assay a reduction in the number of viable cells was observed in the concentration of 1µM for compound 1 (56.54% viable cells, p < 0.001) and compound 3 (38.45% viable cells, p< 0.001). The morphology of HL-60 cells evaluated with the use of the May-Grünwald-Giemsa dye showed cellular death with characteristics of apoptosis which was further confirmed with the orange acridine and ethidium bromide differential count assay (LA/BE), where it was considered statistically significant from the concentration of 2µM for compound 1, with 79,92% (p< 0.001) of cells with characteristics of apoptosis and for compound 3 in the concentration of 1µM with 28,86% (P< 0.001). In the flow cytometry assays it was observed that, when treated with the tested compounds, HL60 cells promoted the externalização of phosphatidyl serine in which in the concentration of 1µM it was considered statistically significant for compound 1 (12.38% of cells in apoptosis, p< 0.001) and for compound 3 (42.67%, p< 0.001). It was observed that the compounds activated caspase 8 (Extrinsic pathway), with 21,78% (P< 0.001) of cells with characteristics of apoptosis for compound 1 (2µM) and 47.5% (p< 0.001) for compound 3 (1µM); they also activated caspase 9 (intrinsic pathway), with 17,10% (p< 0.001) of cells with characteristics of apoptosis for compound 1 (1µM) and 33.55% (p< 0.001) for compound 3 (1µM); consequently, it was activated caspases 3 and 7, involved in the final process of apoptosis, with 30,05% (p< 0.001) of cells with characteristics of apoptosis for compound 1 (2µM) and 53.19% (p< 0.001) for compound 3 (1µM). Intense DNA fragmentation was observed in cells treated with the tested compounds, where in the concentration of 1µM it was observed 23.13% (p 0.001<, composition 1) and 61.02% (p 0.001<, composition 3) of fragmented DNA. The compounds were not able to generate reactive oxygen species (ROS) and cause direct or indirect damage to the DNA strand. In conclusion, both tested compounds can be considered as molecules with cytotoxic potential, highlighting compound 3 for its slightly higher cytotoxicity and selectivity. These data strengthen the importance to synthesize and to study synthetic compounds with more selective activities for the treatment of cancer.