N-acylhydrazone derivative modulates cell cycle regulators promoting mitosis arrest and apoptosis in estrogen positive MCF-7 breast cancer cells.

Breast cancer is the leading cause of cancer death among women worldwide. About 75% of all diagnosed cases are hormone-positive, which are treated with hormone therapy. However, many patients are refractory or become resistant to the drugs used in therapeutic protocols. In this scenario, it is essential to identify new substances with pharmacological potential against breast cancer. VEGFR2 inhibitors are considered promising antitumor agents not only due to their antiangiogenic activity but also by inhibiting the proliferation of tumor cells. Thus, the present study aimed to evaluate the effects of N-acylhydrazone derivative LASSBio-2029 on the proliferative behavior of MCF-7 cells. We observed a promising antitumor potential of this substance due to its ability to modulate critical cell cycle regulators including mitotic kinases (CDK1, AURKA, AURKB, and PLK1) and CDK inhibitor (CDKN1A). Increased frequencies of abnormal mitosis and apoptotic cells were observed in response to treatment. A molecular docking analysis predicts that LASSBio-2029 could bind to the proto-oncoprotein ABL1, which participates in cell cycle control, interacting with other controller proteins and regulating centrosome-associated tubulins. Finally, we created a gene signature with the downregulated genes, whose reduced expression is associated with a higher relapse-free survival probability in breast cancer patients.

Piperine-Chlorogenic Acid Hybrid Inhibits the Proliferation of the SK-MEL-147 Melanoma Cells by Modulating Mitotic Kinases.

Melanoma is considered the most aggressive form of skin cancer, showing high metastatic potential and persistent high mortality rates despite the introduction of immunotherapy and targeted therapies. Thus, it is important to identify new drug candidates for melanoma. The design of hybrid molecules, with different pharmacophore fragments combined in the same scaffold, is an interesting strategy for obtaining new multi-target and more effective anticancer drugs. We designed nine hybrid compounds bearing piperine and chlorogenic acid pharmacophoric groups and evaluated their antitumoral potential on melanoma cells with distinct mutational profiles SK-MEL-147, CHL-1 and WM1366. We identified the compound named PQM-277 (3a) to be the most cytotoxic one, inhibiting mitosis progression and promoting an accumulation of cells in pro-metaphase and metaphase by altering the expression of genes that govern G2/M transition and mitosis onset. Compound 3a downregulated FOXM1, CCNB1, CDK1, AURKA, AURKB, and PLK1, and upregulated CDKN1A. Molecular docking showed that 3a could interact with the CUL1-RBX1 complex, which activity is necessary to trigger molecular events essential for FOXM1 transactivation and, in turn, G2/M gene expression. In addition, compound 3a effectively induced apoptosis by increasing BAX/BCL2 ratio. Our findings demonstrate that 3a is an important antitumor candidate prototype and support further investigations to evaluate its potential for melanoma treatment, especially for refractory cases to BRAF/MEK inhibitors.

Diallyl Disulfide Induces Chemosensitization to Sorafenib, Autophagy, and Cell Cycle Arrest and Inhibits Invasion in Hepatocellular Carcinoma.

Hepatocellular carcinoma is the seventh most common type of cancer in the world, with limited treatment options. A promising strategy to treat cancer is to associate chemotherapeutics and plant bioactive compounds. Here, we examined whether diallyl disulfide (DADS; 50-200 µM) and sorafenib (SORA; 8 µM), either alone or in combination, were toxic to hepatocellular carcinoma cells (HepG2) in vitro. We assessed whether DADS and/or SORA induced cell death (LIVE/DEAD assay and autophagy) and cell cycle changes (flow cytometry), altered expression of key genes and proteins (RT-qPCR and Western blot), and modulated tumorigenesis signatures, such as proliferation (clonogenic assay), migration (wound healing), and invasion (inserts). The DADS + SORA combination elicited autophagic cell death by upregulating LC3 and NRF2 expression and downregulating FOS and TNF expression; induced the accumulation of cells in the G1 phase which thereby upregulated the CHEK2 expression; and inhibited invasion by downregulating the MMP2 expression. Predictive analysis indicated the participation of the MAPK pathway in the reported results. The DADS + SORA combination suppressed both cell invasion and clonogenic survival, which indicated that it dampened tumor growth, proliferation, invasion, and metastatic potential. Therefore, the DADS + SORA combination is a promising therapy to develop new clinical protocols.

Epigenetic changes induced in mice liver by methionine-supplemented and methionine-deficient diets.

A diet deficient in donors of methyl group, such as methionine, affects DNA methylation and hepatic lipid metabolism. Methionine also affects other epigenetic mechanisms, such as microRNAs. We investigated the effects of methionine-supplemented or methionine-deficient diets on the expression of chromatin-modifying genes, global DNA methylation, the expression and methylation of genes related to lipid metabolism, and the expression of microRNAs in mouse liver. Female Swiss albino mice were fed a control diet (0.3% methionine), a methionine-supplemented diet (2% methionine), and a methionine-deficient diet (0% methionine) for 10 weeks. The genes most affected by the methionine-supplemented diet were associated with histone and DNA methyltransferases activity, while the methionine-deficient diet mostly altered the expression of histone methyltransferases genes. Both diets altered the global DNA methylation and the expression and gene-specific methylation of the lipid metabolism gene Apoa5. Both diets altered the expression of several liver homeostasis-related microRNAs, including miR-190b-5p, miR-130b-3p, miR-376c-3p, miR-411-5p, miR-29c-3p, miR-295-3p, and miR-467d-5p, with the methionine-deficient diet causing a more substantial effect. The effects of improper amounts of methionine in the diet on liver pathologies may involve a cooperative action of chromatin-modifying genes, which results in an aberrant pattern of global and gene-specific methylation, and microRNAs responsible for liver homeostasis.

Caffeic acid and chlorogenic acid cytotoxicity, genotoxicity and impact on global DNA methylation in human leukemic cell lines.

Dietary phenolic compounds such as caffeic and chlorogenic acid exert an antiproliferative effect and modulate the gene-specific DNA methylation status in human breast tumor cells, but it remains unclear whether they interfere with global DNA methylation in human leukemia cells. We examined whether caffeic and chlorogenic acid (1-250 µM) exert antitumor action in human promyelocytic leukemia cells (HL-60) and human acute T-cell leukemia cells (Jurkat). Caffeic and chlorogenic acid did not reduce cell viability in the two cell lines, as assessed using the neutral red uptake and MTT assays. These phenolic acids (1-100 µM) neither induced DNA damage (comet assay) nor increased the micronuclei frequency (micronucleus assay) in HL-60 and Jurkat cells, indicating that they were not genotoxic or mutagenic. Analysis of global DNA methylation levels using a 5-mC DNA ELISA kit revealed that chlorogenic acid at a non-cytotoxic concentration (100 µM) induced global DNA hypomethylation in Jurkat cells, but not in HL-60 cells, suggesting that it exerts a cell-specific effect. Caffeic acid did not change global DNA methylation. As other phenolic compounds, chlorogenic acid probably modulates DNA methylation by targeting DNA methyltransferases. The hypomethylating action of chlorogenic acid can be beneficial against hematological malignances whose pathogenic processes involve impairment of DNA methylation.

Effects of sulforaphane on the oxidative response, apoptosis, and the transcriptional profile of human stomach mucosa cells in vitro.

Oxidative stress is a critical factor in the pathogenesis of several gastrointestinal diseases. Sulforaphane (SFN), a bioactive compound found in cruciferous vegetables, activates the redox-sensitive nuclear erythroid 2-related factor 2 (NRF2). In addition to its protective role, SFN exerts cytotoxic effects on cancer cells. However, there is a lack of information concerning the toxicity of SFN in normal cells. We investigated the effects of SFN on cell viability, antioxidant defenses, and gene expression in human stomach mucosa cells (MNP01). SFN reduced ROS formation and protected the cells against induced oxidative stress but high concentrations increased apoptosis. An intermediate SFN concentration (8 µM) was chosen for RNA sequencing studies. We observed upregulation of genes of the NRF2 (antioxidant) pathway, the DNA damage response, and apoptosis signaling; whereas SFN downregulated cell cycle and DNA repair pathway genes. SFN may be cytoprotective at low concentrations and cytotoxic at high concentrations.

Transcriptome and DNA methylation changes modulated by sulforaphane induce cell cycle arrest, apoptosis, DNA damage, and suppression of proliferation in human liver cancer cells.

Abnormal epigenetic alterations are one of the keystones of cancer development. Epigenetic targeting drugs have become a promising and effective cancer therapy strategy. However, due to the high toxicity and unclear mechanisms of action of these drugs, natural compounds that cause epigenetic modulation have also been studied. Sulforaphane (SFN) is a promising bioactive compound for epigenetic targeting therapy. In this study, we investigate the effects of SFN on gene expression and DNA methylation in human hepatocellular carcinoma cells (HepG2). Using high throughput technologies in combination with cell-based assays, we find SFN is a potent anticancer agent, as it induces DNA damage, mitotic spindle abnormalities followed by apoptosis and proliferation inhibition in HepG2 cells. Our results show the upregulation of DNA damage response and cell cycle checkpoint genes. Also, we find the downregulation of cellular pathways frequently overexpressed in human cancer. As expected, SFN exerts epigenetic modulation effects by inhibiting histone deacetylases (HDACs). SFN might affect the activity of oncogenic transcription factors through methylation of its binding sites motifs. Our findings offer insights into SFN chemopreventive molecular effects in HepG2 cells and highlight SFN as a valuable natural approach to cancer therapy for future investigation.

BjussuLAAO-II induces cytotoxicity and alters DNA methylation of cell-cycle genes in monocultured/co-cultured HepG2 cells.

BACKGROUND: The use of animal venoms and their toxins as material sources for biotechnological applications has received much attention from the pharmaceutical industry. L-amino acid oxidases from snake venoms (SV-LAAOs) have demonstrated innumerous biological effects and pharmacological potential against different cancer types. Hepatocellular carcinoma has increased worldwide, and the aberrant DNA methylation of liver cells is a common mechanism to promote hepatic tumorigenesis. Moreover, tumor microenvironment plays a major role in neoplastic transformation. To elucidate the molecular mechanisms responsible for the cytotoxic effects of SV-LAAO in human cancer cells, this study aimed to evaluate the cytotoxicity and the alterations in DNA methylation profiler in the promoter regions of cell-cycle genes induced by BjussuLAAO-II, an LAAO from Bothrops jaracussu venom, in human hepatocellular carcinoma (HepG2) cells in monoculture and co-culture with endothelial (HUVEC) cells. METHODS: BjussuLAAO-II concentrations were 0.25, 0.50, 1.00 and 5.00 µg/mL. Cell viability was assessed by MTT assay and DNA methylation of the promoter regions of 22 cell-cycle genes by EpiTect Methyl II PCR array. RESULTS: BjussuLAAO-II decreased the cell viability of HepG2 cells in monoculture at all concentrations tested. In co-culture, 1.00 and 5.00 µg/mL induced cytotoxicity (p < 0.05). BjussuLAAO-II increased the methylation of CCND1 and decreased the methylation of CDKN1A in monoculture and GADD45A in both cell-culture models (p < 0.05). CONCLUSION: Data showed BjussuLAAO-II induced cytotoxicity and altered DNA methylation of the promoter regions of cell-cycle genes in HepG2 cells in monoculture and co-culture models. We suggested the analysis of DNA methylation profile of GADD45A as a potential biomarker of the cell cycle effects of BjussuLAAO-II in cancer cells. The tumor microenvironment should be considered to comprise part of biotechnological strategies during the development of snake-toxin-based novel drugs.

Analysis of the cytotoxic, genotoxic, mutagenic, and pro-oxidant effect of synephrine, a component of thermogenic supplements, in human hepatic cells in vitro.

Thermogenic supplements containing synephrine (SN) are widely used to weight loss. SN is a proto-alkaloid naturally found in the bark of immature fruits of Citrus aurantium (bitter orange) that has been added to thermogenic supplements due to its chemical and pharmacological similarity with adrenergic amines, such as ephedrine and amphetamines. Although orally ingested SN is mainly metabolized in the liver, it remains unclear whether it affects the redox status and genetic material of human hepatic cells. The present study aims to examine whether SN affects cell viability, cell cycle, redox balance, genomic stability, and expression of the DNA damage response (DDR)-related genes ATM, ATR, CHEK1, CHECK2, TP53, and SIRT1 in HepG2 cells - used as in vitro hepatocyte model. SN induced overproduction of intracellular reactive oxygen species (ROS) after 6 h of treatment with the three concentrations tested (2, 20 and 200 µM). After 24 h of treatment, SN at 200 µM induced intracellular ROS overproduction and exerted cytostatic effects, while SN at 20 and 200 µM increased the levels of GPx and GSH. SN was not cytotoxic (2-5000 µM), genotoxic, and mutagenic and did not alter the expression of DDR-related genes (2-200 µM), indicating that the fast/specific SN metabolization and upregulation of antioxidant defense components to detoxify intracellular ROS were sufficient to prevent intracellular damage in HepG2 cells. In conclusion, SN showed no cytotoxic, genotoxic, and mutagenic potential at relevant concentrations for thermogenic users in human hepatic cells in vitro, although, it plays pro-oxidative action, and cytostatic effects. Taken together, our results suggest that other investigations about the hazard absence of this thermogenic compound should be performed.

Novel lawsone-containing ruthenium(II) complexes: Synthesis, characterization and anticancer activity on 2D and 3D spheroid models of prostate cancer cells.

This study describes a series of newly synthesized phosphine/diimine ruthenium complexes containing the lawsone as bioligand with enhanced cytotoxicity against different cancer cells, and apoptosis induction in prostatic cancer cells DU-145. The complexes [Ru(law)(N-N)2]PF6 where N-N is 2,2'-bipyridine (1) or 1,10-phenanthroline (2) and [Ru(law)(dppm)(N-N)]PF6, where dppm means bis(diphenylphosphino)methane, N-N is 2,2'-bipyridine (3) or 1,10-phenanthroline (4), and law is lawsone, were synthesized and fully characterized by elemental analysis, molar conductivity, NMR, UV-vis, IR spectroscopies and cyclic voltammetry. The interaction of the complexes (1-4) with DNA was evaluated by circular dichroism, gel electrophoresis, and fluorescence, and the complexes presented interactions by the minor grooves DNA. The phosphinic series of complexes exhibited a remarkably broad spectrum of anticancer activity with approximately 34-fold higher than cisplatin and 5-fold higher than doxorubicin, inhibiting the growth of 3D tumor spheroids and the ability to retain the colony survival of DU-145 cells. Also, the complex (4) inhibits DU-145 cell adhesion and migration potential indicating antimetastatic properties. The mechanism of its anticancer activity was found to be related to increased reactive oxygen species (ROS) generation, increased the BAX/BCL-2 ratio and subsequent apoptosis induction. Overall, these findings suggested that the complex (4) could be a promising candidate for further evaluation as a chemotherapeutic agent in the prostate cancer treatment.

BjussuLAAO-II induces cytotoxicity and alters DNA methylation of cell-cycle genes in monocultured/co-cultured HepG2 cells

The use of animal venoms and their toxins as material sources for biotechnological applications has received much attention from the pharmaceutical industry. L-amino acid oxidases from snake venoms (SV-LAAOs) have demonstrated innumerous biological effects and pharmacological potential against different cancer types. Hepatocellular carcinoma has increased worldwide, and the aberrant DNA methylation of liver cells is a common mechanism to promote hepatic tumorigenesis. Moreover, tumor microenvironment plays a major role in neoplastic transformation. To elucidate the molecular mechanisms responsible for the cytotoxic effects of SV-LAAO in human cancer cells, this study aimed to evaluate the cytotoxicity and the alterations in DNA methylation profiler in the promoter regions of cell-cycle genes induced by BjussuLAAO-II, an LAAO from Bothrops jaracussu venom, in human hepatocellular carcinoma (HepG2) cells in monoculture and co-culture with endothelial (HUVEC) cells. Methods: BjussuLAAO-II concentrations were 0.25, 0.50, 1.00 and 5.00 μg/mL. Cell viability was assessed by MTT assay and DNA methylation of the promoter regions of 22 cell-cycle genes by EpiTect Methyl II PCR array. Results: BjussuLAAO-II decreased the cell viability of HepG2 cells in monoculture at all concentrations tested. In co-culture, 1.00 and 5.00 μg/mL induced cytotoxicity (p < 0.05). BjussuLAAO-II increased the methylation of CCND1 and decreased the methylation of CDKN1A in monoculture and GADD45A in both cell-culture models (p < 0.05). Conclusion: Data showed BjussuLAAO-II induced cytotoxicity and altered DNA methylation of the promoter regions of cell-cycle genes in HepG2 cells in monoculture and co-culture models. We suggested the analysis of DNA methylation profile of GADD45A as a potential biomarker of the cell cycle effects of BjussuLAAO-II in cancer cells. The tumor microenvironment should be considered to comprise part of biotechnological strategies during the development of snake-toxin-based novel drugs.(AU)

Methionine-supplemented diet affects the expression of cardiovascular disease-related genes and increases inflammatory cytokines in mice heart and liver.

Some important environmental factors that influence the development of cardiovascular diseases (CVD) include tobacco, excess alcohol, and unhealthy diet. Methionine obtained from the diet participates in the synthesis of DNA, proteins, lipids and affects homocysteine levels, which is associated with the elevated risk for CVD development. Therefore, the aim of this study was to investigate the manner in which dietary methionine might affect cellular mechanisms underlying CVD occurrence. Swiss albino mice were fed either control (0.3% DL-methionine), methionine-supplemented (2% DL-methionine), or a methionine-deprived diet (0% DL-methionine) over a 10-week period. The parameters measured included plasma homocysteine concentrations, oxidative stress by reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, levels of inflammatory cytokines IL-1ß, TNF-α, and IL-6, as well as expression of genes associated with CVD. The levels of apolipoprotein A5 (APOA5), a regulator of plasma triglycerides, were measured. The methionine-supplemented diet increased oxidative stress by lowering the GSH/GSSG ratio in heart tissues and decreased expression of the genes Apob, Ctgf, Serpinb2, Spp1, Il1b, and Sell, but elevated expression of Thbs4, Tgfb2, Ccr1, and Vegfa. Methionine-deprived diet reduced expression of Col3a1, Cdh5, Fabp3, Bax, and Hbegf and increased expression of Sell, Ccl5, Itga2, Birc3, Msr1, Bcl2a1a, Il1r2, and Selp. Methionine-deprived diet exerted pro-inflammatory consequences as evidenced by elevated levels of cytokines IL-1ß, TNF-α, and IL-6 noted in liver. Methionine-supplemented diet increased hepatic IL-6 and cardiac TNF-α. Both methionine supplementation and deprivation lowered hepatic levels of APOA5. In conclusion, data demonstrated that a methionine-supplemented diet modulated important biological processes associated with high risk of CVD development.

Vitamin D3 deficiency increases DNA damage and the oxidative burst of neutrophils in a hypertensive rat model.

Deficiency of vitamin D3, a lipophilic micronutrient, plays a role in the development of some chronic diseases. Vitamin D3 deficiency affects 25-50% of the human population and has been associated with increased risk for development of hypertension. DNA damage induced by reactive oxygen species (ROS) occurs more often in hypertensive than in normotensive individuals, and vitamin D3 status can influence this relationship. The aim of this study was to evaluate whether a diet supplemented with (10,000 IU/kg) or deficient in (0 IU/kg) vitamin D3, compared to a vitamin D3 control diet (1000 IU/kg), would modulate DNA damage and ROS production in spontaneously hypertensive rats (SHR) and normotensive control Wistar-Kyoto (WKY) rats after 12 weeks of treatment. ROS production was assessed by measuring the oxidative burst of neutrophils. DNA damage was evaluated using the comet assay in peripheral blood and the micronucleus test in bone marrow and peripheral blood. Vitamin D3 supplementation did not induce DNA damage and did not change neutrophil ROS production in SHR and WKY rats. Vitamin D3 deficiency induced neutrophil ROS production and a high frequency of micronucleus formation in the bone marrow and peripheral blood of SHR rats only, and induced DNA damage (comet) in peripheral blood of both SHR and WKY rats. In conclusion, vitamin D3 deficiency showed a more pronounced effect on hypertensive animals. Population studies are needed to test whether this relationship also exists in humans.

CR-LAAO antileukemic effect against Bcr-Abl(+) cells is mediated by apoptosis and hydrogen peroxide.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the presence of the Bcr-Abl tyrosine kinase protein, which confers resistance to apoptosis in leukemic cells. Tyrosine kinase inhibitors (TKIs) are effectively used to treat CML; however, CML patients in the advanced (CML-AP) and chronic (CML-CP) phases of the disease are usually resistant to TKI therapy. Thus, it is necessary to seek for novel agents to treat CML, such as the enzyme l-amino acid oxidase from Calloselasma rhodostoma (CR-LAAO) snake venom. We examined the antitumor effect of CR-LAAO in Bcr-Abl(+) cell lines and peripheral blood mononuclear cells (PBMC) from healthy subjects and CML patients. CR-LAAO was more cytotoxic towards Bcr-Abl(+) cell lines than towards healthy subjects' PBMC. The H2O2 produced during the enzymatic action of CR-LAAO mediated its cytotoxic effect. The CR-LAAO induced apoptosis in Bcr-Abl(+) cells, as detected by caspases 3, 8, and 9 activation, loss of mitochondrial membrane potential, and DNA damage. CR-LAAO elicited apoptosis in PBMC from CML-CP patients without TKI treatment more strongly than in PBMC from healthy subjects and TKI-treated CML-CP and CML-AP patients. The antitumor effect of CR-LAAO against Bcr-Abl(+) cells makes this toxin a promising candidate to CML therapy.

Effects of maternal vitamin B6 deficiency and over-supplementation on DNA damage and oxidative stress in rat dams and their offspring.

Vitamin B6 is a cofactor for more than 140 essential enzymes and plays an important role in maternal health and fetal development. The goal of this study was to investigate the effects of maternal vitamin B6 on DNA damage and oxidative stress status in rat dams and their offspring. Female Wistar rats were randomly assigned to three dietary groups fed a standard diet (control diet), a diet supplemented with 30 mg/kg of vitamin B6, or a deficient diet (0 mg/kg of vitamin B6) for 10 weeks before and during mating, pregnancy and lactation. The dams were euthanized at weaning, and their male pups were euthanized either 10 days or 100 days after birth. We found that maternal vitamin B6 deficiency increased the micronucleus frequency in peripheral blood and bone marrow cells and also increased the concentration of hepatic TBARS (thiobarbituric acid reactive substances) in newborn pups (10 days old). In conclusion, maternal 5- to 6-fold over-supplementation of vitamin B6 had no adverse effects, however its deficiency may induce chromosomal damage and hepatic lipid peroxidation in the offspring.

Diet carotenoid lutein modulates the expression of genes related to oxygen transporters and decreases DNA damage and oxidative stress in mice.

Lutein (LT) is a carotenoid obtained by diet and despite its antioxidant activity had been biochemically reported, few studies are available concerning its influence on the expression of antioxidant genes. The expression of 84 genes implicated in antioxidant defense was quantified using quantitative reverse transcription polymerase chain reaction array. DNA damage was measured by comet assay and glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) were quantified as biochemical parameters of oxidative stress in mouse kidney and liver. cDDP treatment reduced concentration of GSH and increased TBARS, parameters that were ameliorated in treatment associated with LT. cDDP altered the expression of 32 genes, increasing the expression of GPx2, APC, Nqo1 and CCs. LT changed the expression of 37 genes with an induction of 13 mainly oxygen transporters. In treatments associating cDDP and LT, 30 genes had their expression changed with a increase of the same genes of the cDDP treatment alone. These results suggest that LT might act scavenging reactive species and also inducing the expression of genes related to a better antioxidant response, highlighting the improvement of oxygen transport. This improved redox state of the cell through LT treatment could be related to the antigenotoxic and antioxidant effects observed.

Effect of methionine-deficient and methionine-supplemented diets on the hepatic one-carbon and lipid metabolism in mice.

SCOPE: A compromised nutritional status in methyl-group donors may provoke several molecular alterations triggering the development of nonalcoholic fatty liver disease (NAFLD) in humans and experimental animals. In this study, we investigated a role and the underlying molecular mechanisms of methionine metabolic pathway malfunctions in the pathogenesis of NAFLD. METHODS AND RESULTS: We fed female Swiss albino mice a control (methionine-adequate) diet and two experimental (methionine-deficient or methionine-supplemented) diets for 10 weeks, and the levels of one-carbon metabolites, expression of one-carbon and lipid metabolism genes in the livers were evaluated. We demonstrate that both experimental diets increased hepatic levels of S-adenosyl-l-homocysteine and homocysteine, altered expression of one-carbon and lipid metabolism genes, and caused lipid accumulation, especially in mice fed the methionine-deficient diet. Markers of oxidative and ER stress response were also elevated in the livers of mice fed either diet. CONCLUSION: Our findings indicate that both dietary methionine deficiency and methionine supplementation can induce molecular abnormalities in the liver associated with the development of NAFLD, including deregulation in lipid and one-carbon metabolic pathways, and induction of oxidative and ER stress. These pathophysiological events may ultimately lead to lipid accumulation in the livers, triggering the development of NAFLD.

Methionine concentration in the diet has a tissue-specific effect on chromosomal stability in female mice.

Inadequate nutrient intake can influence the genome. Since methionine is an essential amino acid that may influence DNA integrity due to its role in the one-carbon metabolism pathway, we were interested in whether methionine imbalance can lead to genotoxic events. Adult female Swiss mice were fed a control (0.3% dl-methionine), methionine-supplemented (2.0% DL-methionine) or methionine-deficient (0% DL-methionine) diet over a 10-week period. Chromosomal damage was assessed in peripheral blood using a micronucleus test, and DNA damage was assessed in the liver, heart and peripheral blood tissues using a comet assay. The mRNA expression of the mismatch repair genes Mlh1 and Msh2 was analyzed in the liver. The frequency of micronucleus in peripheral blood was increased by 122% in the methionine-supplemented group (p<0.05). The methionine-supplemented diet did not induce DNA damage in the heart and liver tissues, but it increased DNA damage in the peripheral blood. The methionine-deficient diet reduced basal DNA damage in liver tissue. This reduction was correlated with decreased mRNA expression of Msh2. Our results demonstrate that methionine has a tissue-specific effect because methionine-supplemented diet induced both chromosomal and DNA damage in peripheral blood while the methionine-deficient diet reduced basal DNA damage in the liver.

In vivo genotoxicity and oxidative stress evaluation of an ethanolic extract from piquiá (Caryocar villosum) pulp.

In this study, the ethanolic extract obtained from piquiá pulp was assessed for genotoxicity and oxidative stress by employing the micronucleus test in bone marrow and peripheral blood cells in addition to comet, thiobarbituric-acid-reactive substances (TBARS), and reduced glutathione assays in the liver, kidney, and heart. Additionally, phytochemical analyses were performed to identify and quantify the chemical constituents of the piquiá extract. Wistar rats were treated by gavage with an ethanolic extract from piquiá pulp (75 mg/kg body weight) for 14 days, and 24 h prior to euthanasia, they received an injection of saline or doxorubicin (15 mg/kg body weight, intraperoneally). The results demonstrated that piquiá extract at the tested dose was genotoxic but not mutagenic, and it increased the TBARS levels in the heart. Further studies are required to fully elucidate how the properties of ethanolic extract of piquiá pulp can affect human health.

Bixin and norbixin protect against DNA-damage and alterations of redox status induced by methylmercury exposure in vivo.

Populations in the Amazon are exposed to organic mercury via consumption of contaminated foods. These ethnic groups consume a specific plant seed "annatto" which contains certain carotenoids. The aim of this study was to find out if these compounds (bixin, BIX and norbixin, NOR), protect against DNA-damage caused by the metal. Therefore, rats were treated orally with methylmercury (MeHg) and with the carotenoids under conditions that are relevant to humans. The animals were treated either with MeHg (30 µg/kg/bw/day), BIX (0.1-10 mg/kg/bw/day), NOR (0.01-1.0 mg/kg/bw/day) or combinations of the metal compound and the carotenoids consecutively for 45 days. Subsequently, the glutathione levels (GSH) and the activity of catalase were determined, and DNA-damage was measured in hepatocytes and leukocytes using single cell gel electrophoresis assays. Treatment with the metal alone caused a decrease in the GSH levels (35%) and induced DNA damage, which resulted in increased DNA migration after electrophoresis in liver and blood cells, whereas no effects were seen with the carotenoids alone. When BIX or NOR were given in combination with organic mercury, the intermediate and the highest concentrations of the carotenoids (1.0 and 10.0 mg/kg/bw/day BIX and 0.1 and 1.0 mg/kg/bw/day NOR) protected against DNA-damage. Furthermore, we found with both carotenoids, a moderate increase in the GSH levels in both metal-treated and untreated animals, while the activities of catalase remained unchanged. Our results indicate that consumption of BIX and NOR may protect humans against the adverse health effects caused by exposure to organic mercury.