CYP1-Activation and Anticancer Properties of Synthetic Methoxylated Resveratrol Analogues.

Naturally occurring stilbenoids, such as the (E)-stilbenoid resveratrol and the (Z)-stilbenoid combretastatin A4, have been considered as promising lead compounds for the development of anticancer drugs. The antitumour properties of stilbenoids are known to be modulated by cytochrome P450 enzymes CYP1A1 and CYP1B1, which contribute to extrahepatic phase I xenobiotic and drug metabolism. Thirty-four methyl ether analogues of resveratrol were synthesised, and their anticancer properties were assessed, using the MTT cell proliferation assay on a panel of human breast cell lines. Breast tumour cell lines that express CYP1 were significantly more strongly affected by the resveratrol analogues than the cell lines that did not have CYP1 activity. Metabolism studies using isolated CYP1 enzymes provided further evidence that (E)-stilbenoids can be substrates for these enzymes. Structures of metabolic products were confirmed by comparison with synthetic standards and LC-MS co-elution studies. The most promising stilbenoid was (E)-4,3',4',5'-tetramethoxystilbene (DMU212). The compound itself showed low to moderate cytotoxicity, but upon CYP1-catalysed dealkylation, some highly cytotoxic metabolites were formed. Thus, DMU212 selectively affects proliferation of cells that express CYP1 enzymes.

Significant metabolic improvement by a water extract of olives: animal and human evidence.

PURPOSE: Dyslipidemia and impaired glucose metabolism are the main health issues of growing prevalence and significant high healthcare cost, requiring novel prevention and/or therapeutic approaches. Epidemiological and animal studies revealed that olive oil is an important dietary constituent, inducing normolipidemia. However, no studies have specifically investigated the polyphenol-rich water extract of olives (OLWPE), generated during olive oil production. METHODS: In the present work, we initially examined the effect of OLPWE on animals' metabolic parameters. Rats fed with a high-fat diet were treated with three different doses of OLPWE for 4 months. Additionally, bioavailability was explored. Afterwards, OLWPE's metabolic effect was explored in humans. Healthy volunteers consumed microencapsulated OLWPE for 4 weeks, in a food matrix [one portion (30 g) of a meat product]. RESULTS: High-fat-fed rats developed a metabolic dysfunction, with increased LDL and insulin levels and decreased HDL; this syndrome was significantly impaired when treated with OLWPE. Treated rats had increased total plasma antioxidant capacity, while several phenolic compounds were detected in their blood. These findings were also verified in humans that consumed OLWPE, daily, for 4 weeks. Interestingly, in individuals with elements of cardio-metabolic risk, OLWPE consumption resulted in reduced glucose, insulin, total cholesterol, LDL and oxLDL levels. CONCLUSIONS: Our data clearly show that OLWPE can improve glucose and lipid profile, indicating its possible use in the design of functional food and/or therapeutic interventions.

Intestinal microbiota and colorectal cancer: a new aspect of research.

Colon holds a complex microbial community, which is crucial for maintaining homeostasis and regulating metabolic functions, supporting the intestinal barrier and controlling immune responses. Previous studies have supported a link between intestinal microbiota and colorectal cancer (CRC). Based on these fndings, the present review analyzed the numerous interactions that occur between microbiota and CRC, starting from the role of intestinal microbiota in colonic homoeostasis. Intestinal microbiota is a cause of CRC and involves various mechanisms such as chronic inflammation, the production of genotoxins causing DNA impairment and/or the biosynthesis of toxic compounds. Moreover, basic metabolic factors such as short-chain fatty acids (SCFAs) and bile acids are included in CRC pathogenesis. Different pathogenic pathways have been reported among different CRC regions (proximal or distal). Variations in the microbial populations are reported between the CRC from these colonic sites, possibly reflecting the bacterial dysbiosis and bioflm distribution. Bowel preparation is essential prior to colonoscopy and surgery; there is, however, minor consensus on the effects of this procedure on intestinal microbiota, notably with regard to the long-term outcomes. With regard to the therapeutic strategy in CRC, the intestinal microbiota is further involved in the modulation of the host response to chemotherapeutic agents (5-fluorouracil and irinotecan) by the interference with drug efcacy and by adverse effects and associated toxicity. In addition, the newly emerged research on CRC immunotherapy reveals an important interplay between intestinal microbiota and the immune system, which includes the possibility of targeting microbiota for the enhancement of anticancer treatment. Additional studies will further clarify the interaction between microbiota and CRC, resulting in the development of alternative therapeutic strategies by manipulating microbiota composition.

Genetic diversity of the KCNE1 gene and susceptibility to postoperative atrial fibrillation.

BACKGROUND: The human KCNE1 protein forms the ß-subunit of the IKs potassium channel and is important in the regulation of the atrial action potential duration. The purpose of this study was to investigate the association between the nonsynonymous 112G>A mutation of the KCNE1 gene and postcardiac surgery atrial fibrillation (AF). METHODS AND RESULTS: A cohort of patients scheduled for cardiac surgery was prospectively recruited. The genotype of 112G>A polymorphism was determined using polymerase chain reaction/restriction fragment analysis and confirmed with direct sequencing of the polymerase chain reaction product. In total, 509 patients were recruited in the study, of whom 203 (39.9%) had at least 1 qualifying episode of postoperative AF. An increased frequency of the G allele was observed in the postoperative AF group compared with the group without postoperative AF (0.628 vs 0.552, respectively, P = .016). The individual's relative risk of postoperative AF increased as the number of G alleles increased from 1.36 (95% CI 0.89-2.08) for G allele heterozygotes to 1.62 (95% CI 1.08-2.43) for G allele homozygotes (P = .04 for trend). The multivariate analysis revealed the abnormal ejection fraction (odds ratio [OR] 1.585, 95% CI 1.076-2.331, P = .020), age (OR 1.043, 95% CI 1.022-1.064, P < .001), type of surgery (aortic valve replacement) (OR 1.869, 95% CI 1.094-3.194, P = .022), and the 112G>A genotype (OR 1.401 [in additive model], 95% CI 1.052-1.865, P = .021) to be independent predictors of postoperative AF. CONCLUSION: This study confirmed the association of the 112G>A polymorphism and postoperative AF in a cohort of patients undergoing cardiac surgery.

Expression profile of CYP1A1 and CYP1B1 enzymes in endometrial tumors.

The cytochrome P450 CYP1A1 and CYP1B1 enzymes are phase I extrahepatic enzymes involved in the activation of pro-carcinogenic compounds to carcinogenic metabolites. Although differential overexpression of CYP1A1 and CYP1B1 has been documented at the messenger RNA (mRNA) and protein level, studies that have examined CYP1 expression by enzyme activity assays are limited. In the current study, the expression of CYP1A1 and CYP1B1 was investigated in a panel of human tumors of endometrial origin by quantitative reverse transcriptase PCR (qRT-PCR), Western blotting, and enzyme activity assays. The data revealed that approximately 36 % (5/14) and 43 % (6/14) of the endometrial tumors overexpressed CYP1A1 and CYP1B1 mRNA, whereas in 57 % of the endometrial tumors, CYP1 mRNA levels were downregulated. The mean mRNA levels of CYP1B1 and CYP1A1 in endometrial tumors did not show a significant difference compared to normal tissues (p > 0.05). Western blotting confirmed the qRT-PCR results and CYP1A1 and CYP1B1 proteins were shown to be downregulated in 7/14 (50 %) of the tumors and overexpressed in 4/14 (29 %) of the tumors. As regards to enzyme activity, 21 % (3/14) of the endometrial samples revealed elevated CYP1 activity levels across the tumor counterparts. Overall, the data suggest a putative downregulation of CYP1A1 and CYP1B1 expression in endometrial tumors, whereas overexpression of active CYP1 enzymes in 21 % of the tumors highlights the potential use of the latter enzymes as chemotherapeutic targets in endometrial cancer.

Role of paraoxonase 1 (PON1) in organophosphate metabolism: implications in neurodegenerative diseases.

Organophosphate pesticides are a class of compounds that are widely used in agricultural and rural areas. Paraoxonase 1 (PON1) is a phase-I enzyme that is involved in the hydrolysis of organophosphate esters. Environmental poisoning by organophosphate compounds has been the main driving force of previous research on PON1 enzymes. Recent discoveries in animal models have revealed the important role of the enzyme in lipid metabolism. However although PON1 function is well established in experimental models, the contribution of PON1 in neurodegenerative diseases remains unclear. In this minireview we summarize the involvement of PON1 genotypes in the occurrence of Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis. A brief overview of latest epidemiological studies, regarding the two most important PON1 coding region polymorphisms PON1-L55M and PON1-Q192R is presented. Positive and negative associations of PON1 with disease occurrence are reported. Notably the MM and RR alleles contribute a risk enhancing effect for the development of some neurodegenerative diseases, which may be explained by the reduced lipoprotein free radical scavenging activity that may give rise to neuronal damage, through distinct mechanism. Conflicting findings that fail to support this postulate may represent the human population ethnic heterogeneity, different sample size and environmental parameters affecting PON1 status. We conclude that further epidemiological studies are required in order to address the exact contribution of PON1 genome in combination with organophosphate exposure in populations with neurodegenerative diseases.

Comparative CYP1A1 and CYP1B1 substrate and inhibitor profile of dietary flavonoids.

CYP1A1 and CYP1B1 are two extrahepatic enzymes that have been implicated in carcinogenesis and cancer progression. Selective inhibition of CYP1A1 and CYP1B1 by dietary constituents, notably the class of flavonoids, is a widely accepted paradigm that supports the concept of dietary chemoprevention. In parallel, recent studies have documented the ability of CYP1 enzymes to selectively metabolize dietary flavonoids to conversion products that inhibit cancer cell proliferation. In the present study we have examined the inhibition of CYP1A1 and CYP1B1-catalyzed EROD activity by 14 different flavonoids containing methoxy- and hydroxyl-group substitutions as well as the metabolism of the monomethoxylated CYP1-flavonoid inhibitor acacetin and the poly-methoxylated flavone eupatorin-5-methyl ether by recombinant CYP1A1 and CYP1B1. The most potent inhibitors of CYP1-EROD activity were the methoxylated flavones acacetin, diosmetin, eupatorin and the di-hydroxylated flavone chrysin, indicating that the 4'-OCH(3) group at the B ring and the 5,7-dihydroxy motif at the A ring play a prominent role in EROD inhibition. Potent inhibition of CYP1B1 EROD activity was also obtained for the poly-hydroxylated flavonols quercetin and myricetin. HPLC metabolism of acacetin by CYP1A1 and CYP1B1 revealed the formation of the structurally similar flavone apigenin by demethylation at the 4'-position of the B ring, whereas the flavone eupatorin-5-methyl ether was metabolized to an as yet unidentified metabolite assigned E(5)M1. Eupatorin-5-methyl ether demonstrated a submicromolar IC(50) in the CYP1-expressing cancer cell line MDA-MB 468, while it was considerably inactive in the normal cell line MCF-10A. Homology modeling in conjunction with molecular docking calculations were employed in an effort to rationalize the activity of these flavonoids based on their CYP1-binding mode. Taken together the data suggest that dietary flavonoids exhibit three distinct modes of action with regard to cancer prevention, based on their hydroxyl and methoxy decoration: (1) inhibitors of CYP1 enzymatic activity, (2) CYP1 substrates and (3) substrates and inhibitors of CYP1 enzymes.

Associations of xenobiotic-metabolizing enzyme genotypes PON1Q192R, PON1L55M and CYP1A1*2A MspI with pathological symptoms of a rural population in south Greece.

Paraoxonases and cytochromes P450 constitute two major classes of xenobiotic-metabolizing enzymes involved in the detoxification of pesticide chemicals. In this study, we examined the distribution of two common genetic polymorphisms of the paraoxonase 1 gene and one common polymorphism of the CYP1A1 gene, in relation to pathological diseases occurring in a rural population. Blood and hair samples were collected from 220 participants of an agricultural cohort in the south of Greece for genotype and pesticide analysis. Demographic information and disease status of the participants was obtained by questionnaire, medical examination and medical record. Organochlorine pesticides and metabolites (DDTs, HCHs) were extracted from hair and analyzed using gas chromatography combined with mass spectrometry techniques. Our results indicate exposure of the rural population of Amaliada to organophosphate and past exposure to organochlorine pesticides. Genotypic analysis of PON1Q192R, PON1L55M and CYP1A1*2A MspI polymorphisms was performed using PCR-RFLP. The PON1 192R and 55M alleles absence was significantly associated with hypertension (OR: 2.59; 95% CI: 1.10-6.09) and hepatitis (OR: 21.43; 95% CI: 2.53-181.50), respectively, as indicated from backward logistic regression. Although the presence of PON1 192R allele significantly affected the occurrence of prostate hyperplasia (OR: 0.35; 95% CI: 0.03-0.40), no associations were obtained between the paraoxonase serum activity or the CYP1A1 genotype and the disease status.

Cytochrome P450 CYP1A1: wider roles in cancer progression and prevention.

CYP1A1 is one of the main cytochrome P450 enzymes, examined extensively for its capacity to activate compounds with carcinogenic properties. Continuous exposure to inhalation chemicals and environmental carcinogens is thought to increase the level of CYP1A1 expression in extrahepatic tissues, through the aryl hydrocarbon receptor (AhR). Although the latter has long been recognized as a ligand-induced transcription factor, which is responsible for the xenobiotic activating pathway of several phase I and phase II metabolizing enzymes, recent evidence suggests that the AhR is involved in various cell signaling pathways critical to cell cycle regulation and normal homeostasis. Disregulation of these pathways is implicated in tumor progression. In addition, it is becoming increasingly evident that CYP1A1 plays an important role in the detoxication of environmental carcinogens, as well as in the metabolic activation of dietary compounds with cancer preventative activity. Ultimately the contribution of CYP1A1 to cancer progression or prevention may depend on the balance of procarcinogen activation/detoxication and dietary natural product extrahepatic metabolism.

Anticancer effects of the flavonoid diosmetin on cell cycle progression and proliferation of MDA-MB 468 breast cancer cells due to CYP1 activation.

Flavonoids constitute a large class of polyphenolic compounds with cancer preventative properties. We have examined the ability of the natural flavone diosmetin to inhibit proliferation of breast adenocarcinoma MDA-MB 468 and normal breast MCF-10A cells and found that this compound is selective for the cancer cells with slight toxicity in the normal breast cells. Diosmetin was metabolised to the structurally similar flavone luteolin in MDA-MB 468 cells, whereas no metabolism was seen in MCF-10A cells. Diosmetin caused G1 arrest at 10 microM in MDA-MB 468 cells after 48-h treatment whereas this effect was not observed in MCF-10A cells. We suggest that diosmetin exerts cytostatic effects in MDA-MB 468 cells, due to CYP1A1 and CYP1B1 catalyzed conversion to the flavone luteolin.

The methoxylated flavones eupatorin and cirsiliol induce CYP1 enzyme expression in MCF7 cells.

Flavonoids have often been associated with cancer prevention and activity of the human cytochrome P450 enzymes CYP1A1 and CYP1B1 with the occurrence of cancer. The flavones eupatorin (1) and cirsiliol (2) enhanced CYP1 enzyme activity in a concentration-dependent manner in MCF7 human breast adenocarcinoma cells. In the range of 0-2.5 microM, 2 caused a dose-dependent increase in CYP1B1 mRNA levels and an increase in CYP1A1 mRNA. Compound 1 caused an increase in CYP1A1 and CYP1B1 mRNA at higher doses (approximately 5 microM). Both CYP1B1 and CYP1A1 catalyzed the conversion of 2 into an as yet unidentified compound. Application of the CYP1 family inhibitor, acacetin, significantly increased the IC(50) value of 2 in MCF7 cells, but did not significantly affect the action of 1. The data suggest that 2 induces CYP1 enzyme expression in cancer cells and is subsequently converted by CYP1B1 or CYP1A1 into an antiproliferative agent.

Anticancer pyridines induce G2/M arrest and apoptosis via p53 and JNK upregulation in liver and breast cancer cells.

In the present study, the synthesis and biological evaluation of one novel pyridine and one novel pyridone anticancer compound is reported. The compounds 6­(2,4­dimethoxyphenyl)­4­(3,4­methylenedioxyphenyl)­1H­pyridin­2­one (1) and 2­(2,4­dimethoxyphenyl)­4­(3,4­methylenedioxyphenyl)pyridine (2) were synthesized from a chalchone precursor. 1 was more active than 2 in inhibiting the proliferation of MCF­7 and HepG2 cells, whereas HepG2 cells were more sensitive to the antiproliferative activity of these compounds compared with MCF­7 cells. The lowest IC50 value was noted for compound 1 in HepG2 cells (IC50=4.5±0.3 µM). The mechanism of action involved induction of G2/M arrest and apoptosis. Both 1 and 2 further induced downregulation of the cell cycle­associated protein cyclin D1 and upregulation of the cell cycle inhibitors p53 and p21 and the apoptosis­associated protein JNK in HepG2 cells. Compound 1 was further shown to induce phosphorylation of JNK in HepG2 cells. These results demonstrate promising cytostatic effects for the two novel anticancer compounds in human cancer cells.

Nobiletin bioactivation in MDA-MB-468 breast cancer cells by cytochrome P450 CYP1 enzymes.

Nobiletin is a fully methoxylated flavone that has demonstrated anticancer activity via multiple modes of action. In the present study, the metabolism and further antiproliferative activity of nobiletin was evaluated in the CYP1 expressing human breast cancer cell line MDA-MB-468 and the normal breast cell line MCF10A. Nobiletin was metabolized in MDA-MB-468 cells to a single-demethylated derivative assigned NP1. This metabolite was absent in MCF10A cells that did not express CYP1 enzymes. Nobiletin exhibited submicromolar IC50 (0.1 ±â€¯0.04 µM) in MDA-MB-468 cells, whereas it was considerably less active in MCF10A cells (40 µM). In MDA-MB-468 cells that were coincubated with the CYP1 inhibitor acacetin, an approximately 300-fold increase was noted in the IC50 (30 ±â€¯2.4 µM) of nobiletin. In the presence of the CYP1 inhibitor acacetin, the conversion of nobiletin to NP1 was significantly reduced in MDA-MB-468 cells. Furthermore, a significant increase was noted in the population of the cells at the G1 phase, following treatment with nobiletin (10 µM) for 24 h compared with the control cells treated with DMSO (0.1%) alone (55.9 ±â€¯0.14 vs. 45.6 ±â€¯1.96), whereas the cell cycle of MCF10A cells was not significantly altered under the same treatment conditions. Taken collectively, the results suggest that nobiletin is selectively bioactivated in MDA-MB-468 breast cancer cells via metabolism by the cytochrome P450 CYP1 family of enzymes.

Tangeretin inhibits the proliferation of human breast cancer cells via CYP1A1/CYP1B1 enzyme induction and CYP1A1/CYP1B1-mediated metabolism to the product 4' hydroxy tangeretin.

Tangeretin is a polymethoxylated flavone with multifaceted anticancer activity. In the present study, the metabolism of tangeretin was evaluated in the CYP1 expressing human breast cancer cell lines MCF7 and MDA-MB-468 and in the normal breast cell line MCF10A. Tangeretin was converted to 4' OH tangeretin by recombinant CYP1 enzymes and by CYP1 enzymes expressed in MCF7 and MDA-MB-468 cells. This metabolite was absent in MCF10A cells that did not express CYP1 enzymes. Tangeretin exhibited submicromolar IC50 (0.25 ±â€¯0.15 µM) in MDA-MB-468 cells, whereas it was less active in MCF7 cells (39.3 ±â€¯1.5 µM) and completely inactive in MCF10A cells (>100 µM). In MDA-MB-468 cells that were coincubated with the CYP1 inhibitor acacetin, an approximately 70-fold increase was noted in the IC50 (18 ±â€¯1.6 µM) of tangeretin. In the presence of the CYP1 inhibitor acacetin, the conversion of tangeretin to 4' OH tangeretin was significantly reduced in MDA-MB-468 cells (2.55 ±â€¯0.19 µM vs. 6.33 ±â€¯0.12 µM). The mechanism of antiproliferative action involved cell cycle arrest at the G1 phase for MCF7 and MDA-MB-468 cells. Tangeretin was further shown to induce CYP1 enzyme activity and CYP1A1/CYP1B1 protein expression in MCF7 and MDA-MB-468 cells. These results suggest that tangeretin inhibits the proliferation of breast cancer cells via CYP1A1/CYP1B1-mediated metabolism to the product 4' hydroxy tangeretin.

Placental expression of PAPPA, PAPPA-2 and PLAC-1 in pregnacies is associated with FGR.

Fetal growth restriction (FGR) is a gynecological disorder of varying etiology. In the present study, an expression analysis of pregnancy-associated plasma protein A (PAPPA), pregnancy-associated plasma protein A2 (PAPPA2) and placenta-specific-1 (PLAC-1) was conducted in pregnancies with FGR and control pregnancies. Placental tissues were collected from pregnancies with FGR (n=16) and control pregnancies (n=16) and the expression of the genes of interest was examined by qPCR. The mean expression levels of PAPPA and PAPPA2 were significantly lower (P<0.001) in placental tissues from FGR pregnancies compared with tissues from healthy subjects, whereas the opposite pattern was observed for PLAC-1 (P<0.001). PAPPA and PLAC-1 expression in FGR and control subjects correlated with birth weight (P<0.001). The findings suggest a possible pathophysiological link between the development of FGR and the expression of PAPPA, PAPPA2 and PLAC-1.

Quercetin attenuates the hyperoxic lung injury in neonatal mice: Implications for Bronchopulmonary dysplasia (BPD).

Quercetin (QU) is one of the most common flavonoids that are present in a wide variety of fruits, vegetables, and beverages. This compound possesses potent anti-inflammatory and anti-oxidant properties. Supplemental oxygen is routinely administered to premature infants with pulmonary insufficiency. However, hyperoxia is one of the major risk factors for the development of bronchopulmonary dysplasia (BPD), which is also termed chronic lung disease in premature infants. Currently, no preventive approaches have been reported against BPD. The treatment of BPD is notably limited to oxygen administration, ventilatory support, and steroids. Since QU has been shown to be effective in reducing inflammation and oxidative stress in various disease models, we hypothesized that the postnatal QU treatment of newborn mice will protect against hyperoxic lung injury by the upregulation of the phase I (CYP1A/B) and/or phase II, NADPH quinone reductase enzymes. Newborn C57BL/6J mice within 24 h of birth with the nursing dams were exposed to either 21% O2 (air) and/or 85% O2 (hyperoxia) for 7 days. The mice were treated, intraperitoneally (i.p.) once every other day with quercetin, at a concentration of 20 mg/kg, or saline alone from postnatal day (PND) 2-6. The mice were sacrificed on day 7, and lung and liver tissues were collected. The expression levels of CYP1A1, CYP1B1, NQO1 proteins and mRNA as well as the levels of MDA-protein adducts were analyzed in lung and liver tissues. The findings indicated that QU attenuated hyperoxia-mediated lung injury by reducing inflammation and improving alveolarization with decreased number of neutrophil and macrophage infiltration. The attenuation of this lung injury correlated with the upregulation of CYP1A1/CYP1B1/NQO1 mRNA, proteins and the down regulation of NF-kB levels and MDA-protein adducts in lung and liver tissues. The present study demonstrated the potential therapeutic value of quercetin in the prevention and/or treatment of BPD.

Anti-inflammatory effects of soyasapogenol I-αa via downregulation of the MAPK signaling pathway in LPS-induced RAW 264.7 macrophages.

The crude extract of soyasaponins was reported to possess anti-inflammatory activity. We determined the new purity group I saponin, I-αa and I-γa that was isolated from wild soybean (Glycine soja) in terms of its efficacy in protecting RAW 264.7 macrophages from lipopolysaccharide (LPS)-stimuli. Cells were treated with soyasaponin I-αa/I-γa (30-300 µΜ) and LPS (0.1 µg/mL) for 24 h. Soyasaponin I-αa inhibited nitric oxide (NO) production at 100 µg/mL, while soyasaponin I-γa demonstrated this effect at a higher concentration (200 µg/mL). The expression levels of iNOS and COX-2 enzymes were downregulated by both soyasaponins. Soyasaponin I-αa exerted its effect via the TNF-α and IL-1ß cytokines. However, soyasaponin I-γa only inhibited the expression of TNF-α. The inflammatory effect of group I soyasaponin was mainly mediated via the phosphorylation of the p38 and JNK proteins. Collectively, these results suggested the potential anti-inflammatory effects of soyasaponins.

Physiological and anthocyanin biosynthesis genes response induced by vanadium stress in mustard genotypes with distinct photosynthetic activity.

The present study aimed to elucidate the photosynthetic performance, antioxidant enzyme activities, anthocyanin contents, anthocyanin biosynthetic gene expression, and vanadium uptake in mustard genotypes (purple and green) that differ in photosynthetic capacity under vanadium stress. The results indicated that vanadium significantly reduced photosynthetic activity in both genotypes. The activities of the antioxidant enzymes were increased significantly in response to vanadium in both genotypes, although the purple exhibited higher. The anthocyanin contents were also reduced under vanadium stress. The anthocyanin biosynthetic genes were highly expressed in the purple genotype, notably the genes TT8, F3H, and MYBL2 under vanadium stress. The results indicate that induction of TT8, F3H, and MYBL2 genes was associated with upregulation of the biosynthetic genes required for higher anthocyanin biosynthesis in purple compared with the green mustard. The roots accumulated higher vanadium than shoots in both mustard genotypes. The results indicate that the purple mustard had higher vanadium tolerance.

Antiproliferative effects of TSA, PXD­101 and MS­275 in A2780 and MCF7 cells: Acetylated histone H4 and acetylated tubulin as markers for HDACi potency and selectivity.

Inhibition of histone deacetylase enzymes (HDACs) has been well documented as an attractive target for the development of chemotherapeutic drugs. The present study investigated the effects of two prototype hydroxamic acid HDAC inhibitors, namely Trichostatin A (TSA) and Belinostat (PXD­101) and the benzamide Entinostat (MS­275) in A2780 ovarian carcinoma and MCF7 breast adenocarcinoma cells. The three HDACi inhibited the proliferation of A2780 and MCF7 cells at comparable levels, below the µM range. Enzyme inhibition assays in a cell­free system showed that TSA was the most potent inhibitor of total HDAC enzyme activity followed by PXD­101 and MS­275. Incubation of A2780 and MCF7 cells with the hydroxamates TSA and PXD­101 for 24 h resulted in a dramatic increase of acetylated tubulin induction (up to 30­fold for TSA). In contrast to acetylated tubulin, western blot analysis and flow cytometry indicated that the induction of acetylated histone H4 was considerably smaller. The benzamide MS­275 exhibited nearly a 2­fold induction of acetylated histone H4 and an even smaller induction of acetylated tubulin in A2780 and MCF7 cells. Taken together, these data suggest that although the three HDACi were equipotent in inhibiting proliferation of MCF7 and A2780 cells, only the benzamide MS­275 did not induce acetylated tubulin expression, a marker of class IIb HDACs.

Human exposure to endocrine disrupting chemicals: effects on the male and female reproductive systems.

Endocrine disrupting chemicals (EDCs) comprise a group of chemical compounds that have been examined extensively due to the potential harmful effects in the health of human populations. During the past decades, particular focus has been given to the harmful effects of EDCs to the reproductive system. The estimation of human exposure to EDCs can be broadly categorized into occupational and environmental exposure, and has been a major challenge due to the structural diversity of the chemicals that are derived by many different sources at doses below the limit of detection used by conventional methodologies. Animal and in vitro studies have supported the conclusion that endocrine disrupting chemicals affect the hormone dependent pathways responsible for male and female gonadal development, either through direct interaction with hormone receptors or via epigenetic and cell-cycle regulatory modes of action. In human populations, the majority of the studies point towards an association between exposure to EDCs and male and/or female reproduction system disorders, such as infertility, endometriosis, breast cancer, testicular cancer, poor sperm quality and/or function. Despite promising discoveries, a causal relationship between the reproductive disorders and exposure to specific toxicants is yet to be established, due to the complexity of the clinical protocols used, the degree of occupational or environmental exposure, the determination of the variables measured and the sample size of the subjects examined. Future studies should focus on a uniform system of examining human populations with regard to the exposure to specific EDCs and the direct effect on the reproductive system.