Avaliação do potencial citotóxico da biflorina em células de melanoma humano com diferentes padrões genéticos

Abstract

Cancer is a public health problem and thesecond cause of death worldwide. Among many types of cancer, cutaneous melanoma has a notable increasing incidence, high aggressiveness and poor survival. Alternative therapy has been investigated like signaling pathways and molecular mechanisms of target specific genes and proteins of melanoma. Taking into account the antitumor activity of biflorin, substance isolated from Capraria bifloraroots, which is cytotoxic in vitro in many tumor cell lines and antitumor activity in vivolike Erlich and Sarcoma 180. This study aimed to show the activity of biflorin in three different strains of human melanoma - SK -Mel 19, 28 and 103. The study model with three cell lines provided a comparison of the effect of biflorin in different common mutations of human melanomas cell lines.Were evaluated the cytotoxic capacity, cell death mechanism, genotoxic capacity and changes in the expression of BRAF, MELK, TYMS, RAD, MGMT, DNMT1, DNMT3B, MBD1, MBD2, MBD3, MBD4, MeCP2. The biflorin, as well as the agents doxorubicin and dacarbazine (positive control), inhibited proliferation of the three human melanoma cell lines studied and was more cytotoxic against SK-Mel 103, followed by SK-Mel 19 and SK-Mel 28.The IC50mean of biflorin at all times and tested strains were 3.23 ± 0.83 μM, ranging from 1.54 to 9.2 μM. Through crystal violet staining of cells treated with biflorin revealed morphological changes like cytolysis with increased of scattered cellular debris, cytoplasm vacuolization, disruption of chromatin with empty nuclear space. Additionally, in the differential staining LA /BE , we observed an increase in the number of apoptotic cells as there was an increase in the concentration of biflorin, however, the number of necrotic cells did not change. Comet assay revealed a production of single and double strand breaks after treatment with biflorin at concentrations of 2.5 and 5.0 μM. At modified comet assay was observed inhibition of methylationat all concentrations tested at SK-Mel 19 and 28. Biflorin also have shown to decrease the expression of methylation genes DNMT1, MBD1, MBD2, MBD3, MBD4 andMeCP2,genes of cell cycle progressionMELK, gene of DNA replication TYMS,and DNA repair genesRAD and MGMT. The results presented here may indicate the biflorin as animportant cytotoxic agent.