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Chlorophyllin, a semisynthetic compound derived from chlorophyll, has been a focus in cancer prevention because it exerts important biological activities, such as antigenotoxic, antioxidative and anticarcinogenic activities. The aim of this study was to evaluate the effect of chlorophyllin against benzo[a]pyrene toxicity in HepG2/C3A cells. Cells were co-treated (chlorophyllin plus benzo[a]pyrene) and the cell viability, cell growth kinetics, cell cycle, and apoptosis were evaluated. The mRNA levels of cell cycle and apoptotic genes were analyzed. Our results showed that chlorophyllin reduce the antiproliferative effects of benzo[a]pyrene in a multi-specific manner, restoring the normal distribution of the cell cycle and inhibiting the cell death induced by the xenobiotic. Gene expression analysis showed that benzo[a]pyrene decreased the mRNA levels of genes involved in cell cycle control (cyclins and cyclin-dependent kinases) and apoptosis. Cells co-treated with 200 µM of chlorophyllin and benzo[a]pyrene also showed a downregulation of mRNA levels of the genes, but the expression levels of the gene that encodes to tumor protein p53 were maintained near to control. Thus, chlorophyllin is a good candidate as a chemoprotective agent that mitigates the cytotoxic effects benzo[a]pyrene and, thus, might be a promising tool to prevent liver cancer.

Environmental exposure to metals can induce cytotoxic and genotoxic effects in cells and affect the health of the exposed population. To investigate the effects of aluminum (Al) and manganese (Mn), we evaluated their cytogenotoxicity using peripheral blood mononuclear cells (PBMCs) exposed to these metals at previously quantified concentrations in groundwater intended for human consumption. The cell viability, membrane integrity, nuclear division index (NDI), oxidative stress, cell death, cell cycle, and DNA damage were analyzed in PBMCs exposed to Al (0.2, 0.6, and 0.8 mg/L) and Mn (0.1, 0.3, 1.0, and 1.5 for 48 h. We found that Al induced late apoptosis; decreased cell viability, NDI, membrane integrity; and increased DNA damage. However, no significant alterations in the early apoptosis, cell cycle, and reactive oxygen species levels were observed. In contrast, exposure to Mn altered all evaluated parameters related to cytogenotoxicity. Our data show that even concentrations allowed by the Brazilian legislation for Al and Mn in groundwater intended for human consumption cause cytotoxic and genotoxic effects in PBMCs. Therefore, in view of the results found, a comprehensive approach through in vivo investigations is needed to give robustness and validity to the results obtained, thus broadening the understanding of the impacts of metals on the health of environmentally exposed people.

Abstract The α-tomatine is a steroidal glycoalkaloid found in immature tomatoes (Lycopersicon esculentum) that has important biological functions including the inhibition of cancer cell growth and preventing metastasis. This study aimed to evaluate the effects of α-tomatine on cytotoxicity, cellular proliferation, apoptosis, and mRNA expression of APC, CCNA2, β-catenin, CASP9, BAK, BAX and BCL-XL in colorectal adenocarcinoma cell line HT-29. HT29 cells were treated with three concentrations of α-tomatine (0.1, 1 and 10 µg/mL), although only the 1 µg/mL concentration of α-tomatine was used to evaluate genetic expression patterns by real time-PCR. Results showed that α-tomatine was cytotoxic only at the 10 µg/mL concentration. Cell proliferation was significantly inhibited after the first 24 hours of treatment only with concentrations of 10 µg/mL. In contrast, there were no significant differences in apoptosis for any treatment. In the gene expression studies, only APC expression was significantly altered by α-tomatine treatment. In conclusion, α-tomatine has antiproliferative activity in the first 24h of treatment, does not induce apoptosis in this cell line and causes disruption of cell membranes, thereby increasing the expression of APC gene related to cell cycle.

Alzheimer's disease (AD) is the most common form of dementia and has no cure. Therapeutic strategies focusing on the reduction of oxidative stress, modulation of amyloid-beta (Aβ) toxicity and inhibition of tau protein hyperphosphorylation are warranted to avoid the development and progression of AD. The aim of this study was to screen the crude extracts (CEs) and ethyl-acetate fractions (EAFs) of Guazuma ulmifolia, Limonium brasiliense, Paullinia cupana, Poincianella pluviosa, Stryphnodendron adstringens and Trichilia catigua using preliminary in vitro bioassays (acetylcholinesterase inhibition, antioxidant activity and total polyphenol content) to select extracts/fractions and assess their protective effects against Aβ25-35 toxicity in SH-SY5Y cells. The effect of the EAF of S. adstringens on mitochondrial membrane potential, lipid peroxidation, superoxide production and mRNA expression of 10 genes related to AD was also evaluated and the electropherogram fingerprints of EAFs were established by capillary electrophoresis. Chemometric tools were used to correlate the in vitro activities of the samples with their potential to be evaluated against AD and to divide extracts/fractions into four clusters. Pretreatment with the EAFs grouped in cluster 1 (S. adstringens, P. pluviosa and L. brasiliense) protected SH-SY5Y cells from Aβ25-35-induced toxicity. The EAF of S. adstringens at 15.62 μg/mL was able completely to inhibit the mitochondrial depolarization (69%), superoxide production (49%) and Aβ25-35-induced lipid peroxidation (35%). With respect to mRNA expression, the EAF of S. adstringens also prevented the MAPT mRNA overexpression (expression ratio of 2.387x) induced by Aβ25-35, which may be related to tau protein hyperphosphorylation. This is the first time that the neuroprotective effects of these fractions have been demonstrated and that the electropherogram fingerprints for the EAFs of G. ulmifolia, L. brasiliense, P. cupana, P. pluviosa and S. adstringens have been established. The study expands knowledge of the in vitro protective effects and quality control of the evaluated fractions.

The application of quality control tests, such as the comet assay, are essential when adipose-derived stem cells are cultured for therapeutic purposes. However, the steps involved in the development of this assay should be investigated, in order to reduce their influence on genomic damage in cells. The study aimed to evaluate if the cell culture process causes DNA damage, and if variations in the lysis time and pH of the electrophoresis buffer interfere in the genotoxicity results. Four different comet assay protocols were evaluated, and the effects of lysis time and pH conditions of the electrophoresis buffer solution were stated as follows: 2 hours and pH 12; 24 hours and pH 12; 2 hours and pH ≥ 13 and 24 hours and pH ≥ 13. The tail moment was analyzed, and results indicated that at the time cells were detached from the flasks, there was little damage to the DNA in the adipose-derived stem cells, which was confirmed by evaluation of the expression of mRNA genes involved in damage and repair processes of genetic material. Also, the tail moment values ​​did not show significant differences among the four evaluated protocols (p < 0.05), with no indication of damage when compared to the positive control (p < 0.05). Thus, any of the tested protocols can be applied in genotoxicity tests with adipose-derived stem cells, without causing damage to them.