Investigação de citotoxicidade, mecanismo de morte e toxicidade de análogos de chalconas: LQFM064, LQFM157 e LQFM178
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Data
2016-12-05
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Universidade Federal de Goiás
Resumo
In the search for new antineoplastic agents, chalcones, intermediate
compounds in flavonoid biosynthesis, are an interesting group of compounds,
since they present considerable cytotoxic activity against a range of
neoplasms and relatively easy chemical structural modifications. Therefore,
the aim of this study was to analyse the cytotoxic potential of chalcone-type
compounds, and evaluate the mechanisms of cell death triggered by the
most promising prototype on the human mammary adenocarcinoma cell line
MCF-7. To do so, a cytotoxicity assessment of three chalcone-type
(LQFM064, LQFM157 and LQFM178) was carried out using a tetrazolium
salt reduction (MTT) method. Taking into account that LQFM064 was
considered the most promising of the compounds analysed in terms of
cytotoxicity, further tests to elucidate the cell death pathways and to evaluate
the safety profile were carried out. Morphological analysis of the cells was
performed by light microscopy and fluorescence. Cellular apoptosis induction
mechanisms were investigated by analyzing death markers using the flow
cytometry technique. Safety aspects of the compound were also investigated.
Cytotoxicity was analysed using the OECD test method of incorporating the
neutral red dye into murine fibroblast cells (3T3), and using the result of this
assay to predict LD50. Myelotoxic potential was assessed by using the
clonogenic assay of granulocyte macrophage colony-forming units (CFUGM).
The data were analyzed by Analysis of Variance (ANOVA) and a
posteriori by the Tukey test or t-test. The means were considered statistically
significant when P < 0.05. The LQFM 064 prototype was cytotoxic for the
MCF-7 (IC50 = 21 µM) and 3T3 (IC50 = 30 µM) lineages in a concentrationdependent
manner. Treatment of tumor cells with LQFM064 induced
morphological changes suggestive of apoptosis. In addition, several
biochemical alterations indicated cell death by apoptosis, such as: cell cycle
arrest in the G0/G1 phase, the outgrowth of phosphatidylserine, increased
expression of caspases -3/7, -8 and -9, reduced mitochondrial membrane
potential and increased generation of Reactive Oxygen Species (ROS).
Activation of both apoptotic pathways was also seen through modulation of
the proteins involved in the extrinsic and intrinsic pathways. The compound
was myelotoxic to normal bone marrow cells in a concentration-dependent
manner. However, this toxicity was lower for normal than for tumor cells. It
was therefore concluded that the LQFM064 compound triggered alterations
suggestive of apoptosis in MCF-7 tumor cells, and could be considered
promising as an antitumor drug prototype.
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Palavras-chave
Antitumorais , Câncer de mama , Chalconas , MCF-7 , Apoptose , Antitumor , Breast cancer , Chalcones , MCF-7 , Apoptosis
Citação
CABRAL, B. L. S. Investigação de citotoxicidade, mecanismo de morte e toxicidade de análogos de chalconas: LQFM064, LQFM157 e LQFM178. 2016. 105 f. Dissertação (Mestrado em Ciências Farmacêuticas) - Universidade Federal de Goiás, Goiânia, 2016.