Avaliação do potencial antineoplásico dos compostos mesoiônicos MIH 2.4BL e MIH 2.4Zn, pertencentes ao grupo tiolato, e seus possíveis mecanismos de ação

Abstract

Synthetic mesoionic compounds, belonging to the 1,3-thiazolium-5-thiolate group, have an excellent ability to cross cell membranes and interact with several biological molecules with distinct affinities. The present work aimed to evaluate the antineoplastic potential of new mesoionic compounds of the 1,3-thiazolium-5-thiolate group, with or zinc enrichment, and their possible mechanisms of action. For this, the compounds were initially subjected to chemical characterization by obtaining the calibration curve, ultraviolet and visible spectrophotometry (UV-vis), optical emission spectrometry (ICP-OS), photoluminescence spectroscopy, nuclear magnetic resonance, infrared spectroscopy (FT-IR), X-ray and thermogravimetric analysis (TGA). In vitro experimental studies using cervical carcinoma (HEp-2) cell lines, human rectal colon carcinoma (HT-29), human acute promyelocytic leukemia (HL-60), human mammary adenocarcinoma (MCF7), carcinoma human breast cancer (T-47D), rat breast cancer (4T1) and a lineage of healthy transformed cells of murine peritoneal macrophages (RAW 264.7). For the staining with propidium iodide, in flow cytometry, the cell viability in the HL-60 strain was evaluated. For the mitochondrial depolarization test, rhodamine 123 was used and for the evaluation of the cell death pattern, Annexin V was used. Cell cycle analysis and DNA fragmentation were performed with the Guava® cell cycle kit. Subsequently, RNA extraction with Trizol was obtained, cDNA was obtained with ImProm-II ™ Reverse Transcription System (PROMEGA) and expression analysis of BAX, BCL2, CASPASE 3, CASPASE 9 and GAPDH genes as reference control. The results showed that, considering the time of exposure of the cells to the compounds, the lowest IC50 concentration and the best selectivity index (IS), the mesoionic compounds MIH 2.4Bl [3.5 μg / mL (3.0-4.0)] and MIH 2.4Zn [5.0 μg / mL (4.5-5.5)] showed better activity in the HL-60 cell line, in 48 h time, promoting inhibition of the growth of cancer cells with lower toxicity in healthy cells (RAW 264.7). The compounds promoted mitochondrial depolarization in the tested lineage (HL-60), cell death by apoptosis and cell cycle arrest in G2 phase. However, the tested concentrations of the compounds did not promote DNA fragmentation. Regarding the analysis of gene expression, it was observed that the BAX gene presented significant difference only when compared to the expression in the sample BLC1 (MIH 2.4Bl; 3.5 μg / mL) vs. BLC2 (MIH 2.4Bl; 7.0 μg / mL) (p <0.05) and when comparing the expression of the gene in the sample BLC1 vs. ZNC1 (MIH 2.4Zn; 5.0 μg / mL) (p <0.05). For the BCL2 gene, there was a significant difference when compared to the BLC2 sample. ZNC2 (MIH 2.4Zn; 10.0 μg / mL) (p <0.01) and the ZNC1 sample. ZnC2 (p <0.05). Regarding the expression of CASPASE 3, a significant difference was observed when comparing BLC2 vs. BLC1 (p <0.05). And for CASPASE 9 there was a significant difference when compared to the following samples: BLC1 vs. BLC2 (p <0.001); BLC1 vs. ZNC1, BLC1 vs. ZNC2, BLC1 vs. doxorubicin and BLC1 vs. negative control (p <0.01). The synthetic mesoionic compounds analyzed have a potential antitumor effect as candidates for antineoplastic treatment, allowing the continuity of in vitro and in vivo studies for future preclinical analysis.