catechol-O-methyltransferase mRNA Research Articles

Dopamine receptors gene overexpression in the microenvironment of invasive gastric cancer and its potential implications.

Gastric cancer (GC) is the fifth most common cancer worldwide and the most commonly diagnosed cancer in Iran. The nervous system provides proximity to tumor cells by releasing neurotransmitters such as dopamine and presenting them to the corresponding receptor-bearing tumors. While nerve fibers infiltrate the tumor microenvironment, little is known about the expression levels of dopamine (DA), dopamine receptors (DRs), and catechol-O-methyltransferase (COMT) in GC patients. DRs and COMT expression were analyzed in 45 peripheral blood mononuclear cells (PBMCs) and 20 paired tumor and adjacent tissue of GC patients by quantitative polymerase chain reaction. DA was measured in plasma specimens using enzyme-linked immunosorbent assay. Protein-protein interaction analysis was carried out to identify GC-related hub genes. Increased expression of DRD1-DRD3 was found in tumor specimens compared with adjacent non-cancerous specimens (P < 0.05). A positive correlation was found between DRD1 and DRD3 expression (P = 0.009); DRD2 and DRD3 expression (P = 0.04). Plasma levels of dopamine were significantly lower in patients (1298 pg/ml) than in controls (4651 pg/ml). DRD1-DRD4 and COMT were up-regulated in PBMCs of patients compared with controls (P < 0.0001). Bioinformatic analyses showed 30 hub genes associated with Protein kinase A and extracellular signal-regulated kinase signaling pathways. The findings indicated dysregulation of DRs and COMT mRNA expression in GC and suggest that the brain- gastrointestinal axis may mediate gastric cancer development. Network analysis revealed that combination treatments could be considered for optimizing and improving the precision treatment of GC.

Sansoninto attenuates aggressive behavior and increases levels of homovanillic acid, a dopamine metabolite, in social isolation-reared mice

Background and aimEarly-life stress is thought to affect aggressive behavior in humans and rodents. Laboratory experiments have demonstrated that Sansoninto (SST; 酸棗仁湯 suān zǎo rén tāng), a traditional herbal medicine, attenuates stress-induced abnormal behavior in rodents. However, it is unknown whether SST attenuates stress-induced aggressive behavior. The current study examined the effects of SST on aggressive behavior of mice who suffered from social isolation (SI) stress in adolescence. Experimental procedureFive-week old mice were socially isolated for 6 weeks, and SST administration was started at 4 weeks after starting SI. Aggressive behavior and locomotor activity were examined in SST-treated mice. The content of dopamine and its metabolites in the hypothalamus were examined using high-performance liquid chromatography analysis. Gene expression analyses of monoamine oxidase-B (MAO-B), catechol-O-methyltransferase (COMT), and tyrosine hydroxylase in the hypothalamus were performed using quantitative reverse transcription polymerase chain reaction. Results and conclusionSST attenuated SI-induced aggressive behavior and increased levels of homovanillic acid, a metabolite of dopamine. However, SST did not affect dopamine levels. SI enhanced locomotion in a novel environment and increased COMT mRNA levels. In contrast, SST-treated mice showed no significant enhancement of locomotion. SST attenuated the increase in COMT mRNA levels. Given that the dopaminergic system has been implicated in aggressive behavior, these findings suggest that SST toned down dopaminergic signaling, resulting in amelioration of aggression. SST may be useful for treatment of aggressive behavior in patients with neurotic symptoms.

Overexpression of catechol-O-methyltransferase occurs early in the progression of pancreatic cancer

Abstract Aims: Catechol-O-methyltransferase (COMT) plays a role in many kinds of cancer, and its high expression in pancreatic cancer has been found to be related to better prognosis. However, the expression and biological significance of COMT in multistep pancreatic cancerogenesis is not clear. Main methods: Six LSL-KrasG12D-positive and Pdx1-Cre-positive mice (KrasG12D mice), 6 wild-type mice and 1 human tissue microarray were used in this study. COMT protein expression was measured by immunohistochemistry, and DNA chips were made for use in COMT mRNA assays. Key findings: The expression of COMT in pancreatic intraepithelial neoplasias (PanINs) from KrasG12D mice was significantly higher than that in normal pancreatic tissue from wild-type mice, both in terms of protein level and mRNA expression. The median COMT immunohistochemistry expression scores in human PanIN-1 and PanIN-2 were 70 and 160, respectively, which were significantly lower than the score of 170 observed in pancreatic ductal adenocarcinoma (PDAC) (P = .024 and .037, respectively) and significantly higher than the score of 25 observed in pancreatitis (P = .01 and .008, respectively). Significance: In the development of pancreatic cancer from chronic pancreatitis and in the transition of PanIN to PDAC, we observed significantly increased expression of COMT. These data predict that the overexpression of COMT is an early event in the multistep process of pancreatic cancerogenesis.

COMT, 5-HTR2A, and SLC6A4 mRNA Expressions in First-Episode Antipsychotic-Naïve Schizophrenia and Association With Treatment Outcomes.

Background: Dopaminergic and serotonergic systems play crucial roles in the pathophysiology of schizophrenia and modulate response to antipsychotic treatment. However, previous studies of dopaminergic and serotonergic genes expression are sparse, and their results have been inconsistent. In this longitudinal study, we aim to investigate the expressions of Catechol-O-methyltransferase (COMT), serotonin 2A receptor (5-HTR2A), and serotonin transporter gene (SLC6A4) mRNA in first-episode antipsychotic-naïve schizophrenia and to test if these mRNA expressions are associated with cognitive deficits and treatment outcomes or not.Method: We measured COMT, 5-HTR2A, and SLC6A4 mRNA expressions in 45 drug-naive first-episode schizophrenia patients and 38 health controls at baseline, and repeated mRNA measurements in all patients at the 8-week follow up. Furthermore, we also assessed antipsychotic response and cognitive improvement after 8 weeks of risperidone monotherapy.Results: Patients were divided into responders (N = 20) and non-responders groups (N = 25) according to the Remission criteria of the Schizophrenia Working Group. Both patient groups have significantly higher COMT mRNA expression and lower SLC6A4 mRNA expression when compared with healthy controls. Interestingly, responder patients have significantly higher levels of COMT and 5-HTR2A mRNA expressions than non-responder patients at baseline. However, antipsychotic treatment has no significant effect on the expressions of COMT, 5-HTR2A, and SLC6A4 mRNA over 8-week follow up.Conclusion: Our findings suggest that dysregulated COMT and SLC6A4 mRNA expressions may implicate in the pathophysiology of schizophrenia, and that COMT and 5-HTR2A mRNA may be potential biomarkers to predict antipsychotic response.

Cloning and expression of a novel catechol-O-methyltransferase in common marmosets.

Catechol-O-methyltransferase (COMT) catalyzes the O-methylation of endogenous catechol amines and estrogens and exogenous catechol-type of drugs. A Parkinson’s disease model of common marmoset (Callithrix jacchus) has been widely used in preclinical studies to evaluate inhibitory potential of new drug candidates on marmoset COMT. Despite COMT inhibitors could potentiate the pharmacological action of levodopa on Parkinson’s disease in animal models, marmoset COMT cDNA has not yet been identified and characterized. In this study, a cDNA highly homologous to human COMT was cloned from marmoset livers. This cDNA encoded 268 amino acids containing a transmembrane region and critical amino acid residues for catalytic function. The amino acid sequences of marmoset COMT shared high sequence identity (90%) with human COMT. COMT mRNA was expressed in all five tissues tested, including brain, lung, liver, kidney and small intestine, and was more abundant in marmoset liver and kidney. Membrane-bound COMT was immunochemically detected in livers and kidneys, whereas soluble COMT was detected in livers, similar to humans. These results indicated that the molecular characteristics of marmoset COMT were generally similar to the human ortholog.

Abstract 14360: Gene Transfer of Sarco/Endoplasmic reticulum Ca2+-ATPase 2a Restores Pulmonary Artery Endothelial Catechol-O-Methyltransferase Activity to Decrease Norepinephrine Levels in Pulmonary Hypertension

Elevated levels of norepinephrine (NE) may occur in pulmonary hypertension (PH), in part, when activity of catechol- O -methyltransferase (COMT) is decreased. COMT is expressed by pulmonary artery endothelial cells (PAEC), degrades NE, and is negatively regulated by aldosterone (ALDO) and cytosolic Ca 2+ . Expression of the cardiac isoform of the sarco/endoplasmic Ca 2+ -ATPase (SERCA2a) modulates ALDO and cytosolic Ca 2+ and is downregulated in pulmonary arteries in PH. We hypothesized that gene transfer of SERCA2a to pulmonary arteries would prevent the decrease in COMT activity and lower NE levels. Accordingly, human PAEC were infected with an adenovirus encoding SERCA2a to increase expression 4.2-fold (p&lt;0.01) or control virus and exposed to ALDO (10 -7 mol/L), which decreases COMT activity by 59.2 ± 6.2% (p&lt;0.01). Compared to controls, SERCA2a overexpression in PAEC had no effect on COMT mRNA or protein levels but increased COMT activity by 148.8 ± 14.5% (p&lt;0.01) by decreasing cytosolic Ca 2+ levels by 38.2 ± 6.7% (p&lt;0.05). This resulted in a decrease in NE levels in the medium (229.4 ± 20.6 vs. 139.9 ± 14.8 vs. pg/mg protein, p&lt;0.01) and collagen I expression. To examine the in vivo relevance of SERCA2a gene transfer on COMT activity, the rat monocrotaline model of PH was treated with inhaled adeno-associated virus 1 carrying SERCA2a (AAV1.SERCA2a). There was no difference in COMT expression in AAVI.SERCA2a-treated or saline control PH-rats; however, lung COMT activity was increased 139.8 ± 8.2% (p&lt;0.01) while lung levels of NE (366.7 ± 38.6 vs. 504 ± 30.2 pg/ml/mg, p&lt;0.01), serum ALDO, and pulmonary artery collagen 1 were decreased by AAV1.SERCA2a. In the pig pulmonary vein banding model of PH, inhaled AAV1.SERCA2a gene therapy decreased mean pulmonary artery pressure (54 ± 20 vs. 29 ± 5 mmHg, p&lt;0.03); increased COMT activity by 121.1 ± 6.2% (p&lt;0.05); and decreased levels of ALDO by 43.3 ± 4.6% (p&lt;0.03), NE by 43.3 ± 4.6% (p&lt;0.03), and collagen I in remodeled vessels. Taken together, these data indicate that gene therapy with inhaled AAV1.SERCA2a increases COMT activity by decreasing intracellular Ca 2+ , thereby decreasing NE levels. This extends the actions of SERCA2a beyond pulmonary vascular remodeling in PH to modulating levels of circulating catecholamines.

The blood-brain barrier-permeable catechol-O-methyltransferase inhibitor dinitrocatechol suppresses experimental autoimmune encephalomyelitis.

Reduced levels of noradrenaline (NA) in CNS of multiple sclerosis patients could be due to metabolism by catechol-O-methyltransferase (COMT). In mice immunized with myelin oligodendrocyte glycoprotein peptide, the BBB-permeable COMT inhibitor dinitrocatechol (DNC) reduced clinical signs, while entacapone, a non-BBB-permeable inhibitor, had no effect. Spinal cord NA levels were slightly increased by DNC, and there was an inverse correlation between NA levels and average clinical signs. Spinal cord COMT mRNA levels were not increased during EAE, but were found increased in the frontal cortex of MS patients. These results suggest that COMT inhibitors could provide benefit to MS patients.

Catechol-O-methyltransferase Val158Met polymorphism and altered COMT gene expression in the prefrontal cortex of suicide brains

Catechol-O-methyltransferase (COMT) plays a key role in the degradation of catecholamine neurotransmitters within the brain. A functional polymorphism COMT Val158Met has been associated with psychiatric disorders including suicidal behavior. In the present study we examined whether this polymorphism was related to COMT mRNA expression in frontal cortical regions, and whether the expression of COMT differed between depressed suicide victims and psychiatric healthy controls. The Val158Met polymorphism was determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. The levels of COMT mRNA expression in the frontopolar cortex (FPC; 29 suicides vs. 27 controls) and orbital frontal cortex (OFC; 19 suicides vs. 15 controls) were significantly increased among depressed individuals that died by suicide relative to those of controls, being up-regulated by approximately 60% and 65% in the FPC and OFC, respectively. Furthermore, among individuals with the Met allele (Met/Met and Met/Val genotypes) who died by suicide COMT mRNA expression was elevated relative to that of the nondepressed Met allele carriers. However, significant differences were not detected between suicides (n=49) and controls (n=72) with respect to the Val158Met genotypic distribution and allelic frequencies. These results are consistent with the perspective that altered COMT mRNA expression in frontal cortical brain regions might contribute to suicide and/or depression, further supporting the role of dysregulation of catecholaminergic pathway genes in the pathophysiology of suicide behaviors.

Biological Effects of COMT Haplotypes and Psychosis Risk in 22q11.2 Deletion Syndrome

22q11.2 deletion syndrome (22q11.2DS) is the most common genetic syndrome associated with schizophrenia. The catechol-O-methyltransferase (COMT) gene is located in the obligatory deletion region, and possible associations between COMT variants and neuropsychiatric manifestations in 22q11.2DS have been reported. The purpose of the current study was to evaluate the effect of COMT hemizygosity and molecular haplotypes on gene expression and enzyme activity and its association with psychotic symptoms in 22q11.2DS. Lymphoblast samples were drawn from 53 individuals with 22q11.2DS and 16 typically developing control subjects. We measured COMT messenger (m)RNA and protein expression and enzyme activity using standard procedures. The presence of a psychotic disorder and cognitive deficits were also evaluated using structured testing. There was an approximately 50% reduction in COMT mRNA, protein, and enzyme activity levels in 22q11.2DS samples. Haplotype analysis revealed clear phenotypic differences between various Val-containing haplotypes on COMT-3' untranslated region extended mRNA, soluble COMT and membrane-bound proteins, and enzyme activity. The G variant of rs165599, a 3' untranslated region single nucleotide polymorphism, was associated with low levels of COMT expression and with the presence of psychosis and lower performance IQ scores in our 22q11.2DS sample. Finally, we demonstrate that the COMT rs74745580 "T" mutation is associated with absent soluble COMT expression and very low COMT activity in two 22q11.2DS individuals. Our findings confirm a robust effect of COMT hemizygosity on COMT activity and show complex interactions of variants within the COMT gene that influence COMT biology and confound conclusions based on associations with the Val158Met genotype alone.

Reduced expression of COMT in placenta correlates with term preeclampsia

Objective: To investigate the expression of catechol-O- methyltransferase (COMT) in placentas from term preeclampsia patients in a Chinese cohort and to analyze the relationships between COMT and mean artery pressure (MAP), serum uric acid and 24-hour urine protein. Methods: 15 term pregnant patients with preeclampsia and 15 normal pregnant women were enrolled. Clinical characteristics and placental tissue were collected. Placental COMT expression was determined by quantitative real-time PCR technique and immunohistochemistry. Results: The level of COMT mRNA in placentas from the preeclampsia group was significantly decreased than that in the normal pregnant women (0.00179 ± 0.00051 vs. 0.00289 ± 0.00066, t = 5.145, P 0.001). Adjusted by age and body mass index (BMI), the COMT expression was negatively correlated with serum uric acid (r = ?0.660, P r = ?0.717, P r = ?0.619, P

Relative imbalances in the expression of catechol-O-methyltransferase and cytochrome P450 in breast cancer tissue and their association with breast carcinoma

ObjectiveTo investigate the expression levels of genes encoding phase I and phase II estradiol-metabolizing enzymes, and their association with breast cancer risk in Chinese women. MethodsThe mRNA expression levels of cytochrome P450 (CYP) 1A1, 1B1 and 3A4 and catechol-O-methyltransferase (COMT) were examined in the breast tumor tissues, matched adjacent non-tumor tissues and the tissues with benign breast disease (BBD) by fluorescent quantitative real-time PCR. ResultsCompared to BBD tissue, the mRNA expression of CYP1A1, CYP1B1 and CYP3A4 significantly reduced by 81.8%, 77.5%, and 85.6%, respectively, in the breast tumor tissue and by 27.2%, 38.8%, and 51.3%, respectively, in the adjacent non-tumor tissue in average (p<0.0001). COMT mRNA was 6.9 and 6.4 fold higher in the breast tumor and match non-tumor tissue (p<0.0001) than in the BBD, respectively. The level of COMT detected in pre-menopausal group and lymph nodal stage N1–N2 group was lower than that in post-menopausal group (p=0.0292) and N0 group (p=0.0389), respectively. ConclusionSignificantly deceased expression of estradiol-metabolizing enzymes might result in the excess exposure of intratumoural E2, which could be one of the important risk factors for breast cancer. Significantly elevated COMT expression suggested that COMT could play a key role in breast tumor formation.

Abstract 1343: Protective effect of catechol-O-methyltransferase in human renal cell carcinogenesis

Abstract Exposure to carcinogenic catechol estrogens plays a role in the development of kidney cancer. Catechol-O-methyltransferase (COMT) neutralizes the genotoxic effects of these compounds by methoxylation. Although reduced activity of COMT has been suggested as a risk factor for estrogen-associated cancers, its critical role in kidney cancer and underlying mechanisms of renal cell carcinogenesis are largely unknown. To address the role and function of COMT in renal cell carcinomas (RCC), we initially determined levels of COMT in normal kidney and clear cell RCC. The expression of COMT mRNA was down-regulated in clear cell RCC tissues as determined by quantitative PCR. Low expression of COMT protein in clear cell RCC tissues was also confirmed by immunohistochemical counting of staining score (2.5 vs. 0.5 in normal kidney and clear cell RCC, respectively, p&amp;lt;0.001). Since COMT expression is reduced in clear cell RCC compared to normal cells, we explored the function of COMT by transiently over-expressing it in the Caki-1 clear cell RCC cell line with low levels of COMT compared to HK-2 normal renal cells. A significant increase of COMT expression in Caki-1 cells (Caki-1/COMT) compared to parent cells transfected with vector control (Caki-1/pCMV6) was confirmed by both quantitative PCR and Western blot. We investigated the role of COMT on cell proliferation and found that proliferation of Caki-1/COMT cells was decreased by 8 to 15 % in a time dependent manner (from 24 hours to 72 hours, p&amp;lt;0.05). We also assessed the effect of COMT on cell cycle progression by flow cytometry. Over-expression of COMT led to an increase (8 ± 1.6%) in the G0/G1 phase population, whereas the number of cells in S-phase decreased from 5.5 % to 2.6 % (p&amp;lt;0.05). These data indicate that COMT over-expression ameliorate the proliferation of Caki-1 renal cancer cell line by G0/G1 phase arrest. In addition, we analyzed whether COMT expression affects apoptosis of Caki-1 cells by flow cytometry using annexin V-FITC/7-AAD (7-amino actinomycin D) dye. COMT expression resulted in a higher percentage of cells undergoing both early and late apoptosis compared to vector controls (2.3% vs. 0.4 %, respectively for early apoptosis, and 5.5 % vs. 0.8 %, respectively for late apoptosis, p&amp;lt;0.05). Our study indicates that COMT plays a protective role in renal cell carcinogenesis by preventing cellular proliferation and enhancing apoptosis of RCC cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1343. doi:10.1158/1538-7445.AM2011-1343

Abstract CN06-03: Green tea and pomegranate: The role of metabolites in chemoprevention

Abstract CN06-03: Green tea and pomegranate: The role of metabolites in chemoprevention

Vitamin D inhibits proliferation of human uterine leiomyoma cells via catechol- O-methyltransferase

To evaluate the effects and mechanisms of action of vitamin D on human uterine leiomyoma (HuLM) cell proliferation in vitro. Laboratory study. University hospitals. Not applicable. Not applicable. HuLM cells were treated with 1,25-dihydroxyvitamin D3 (vitamin D), and cell proliferation was assayed by the methylthiazolyl tetrazolium technique. proliferating cell nuclear antigen (PCNA), BCL-2, BCL-w, cyclin-dependent kinase (CDK) 1, and catechol-O-methyltransferase (COMT) protein levels were analyzed by Western blotting. COMT mRNA and enzyme activity were assayed by quantitative reverse-transcription polymerase chain reaction (RT-PCR) and high-performance liquid chromatography analysis, respectively. The role of COMT was evaluated in stable HuLM cells by silencing COMT expression. Vitamin D inhibited the growth of HuLM cells by 47±0.03% at 1 μM and by 38±0.02% at 0.1 μM compared with control cells at 120 hours of treatment. Vitamin D inhibited extracellular signal-regulated kinase activation and down-regulated the expression of BCL-2, BCL-w, CDK1, and PCNA. Western blot, RT-PCR, and enzyme assay of COMT demonstrated inhibitory effects of vitamin D on COMT expression and enzyme activity. Silencing endogenous COMT expression abolished vitamin D-mediated inhibition of HuLM cell proliferation. Vitamin D inhibits growth of HuLM cells through the down-regulation of PCNA, CDK1, and BCL-2 and suppresses COMT expression and activity in HuLM cells. Thus, hypovitaminosis D appears to be a risk factor for uterine fibroids.

Expression of catechol-O-methyltransferase in the brain and periphery of normal and MPTP-treated common marmosets

Catechol-O-methyltransferase (COMT) inhibition is widely used to potentiate the effects of levodopa in Parkinson's disease but the effects of nigral dopaminergic cell loss and levodopa treatment on COMT activity are not known. The present study investigated the expression of COMT in the brain and liver of normal common marmosets, and animals treated with MPTP and those treated with levodopa to induce dyskinesia. Reverse transcript PCR demonstrated the expression of COMT mRNA in the liver, cortex and striatum of normal marmosets. Using Western blotting, the presence of two subunits of COMT protein, membrane bound COMT (MB-COMT) and soluble COMT (S-COMT), was shown in the liver, cortex and striatum of normal marmosets. Quantitative analysis of the MB-COMT and S-COMT subunit bands showed that there was no significant difference in the density of bands in MPTP treated marmosets or those exposed to levodopa compared to normal animals. COMT immunoreactivity was expressed in many brain regions including the cortex and striatum. No difference in COMT staining intensity was observed between normal, MPTP exposed or MPTP plus levodopa treated animals. COMT immunostaining was present in most striatal neurones and it was occasionally seen in glial cells. The data from present study demonstrated the expression of COMT mRNA and protein in the brain of common marmoset contrary to a previous report that it is not expressed in this species. COMT activity appears unaffected by loss of the dopaminergic nigro-striatal pathway and levodopa treatment.

Expression of Estrogenicity Genes in a Lineage Cell Culture Model of Human Breast Cancer Progression

The mRNA levels of estrogen receptors (ERα and ERβ), cytosolic sulfotransferases (SULT1E1, SULT1A1, SULT2A1 and SULT2B1), steroid sulfatase (STS), aromatase (CYP19), 17β‐hydroxysteroid dehydrogenases (17βHSD1 and 2), CYP1B1 and catechol‐O‐methyltransferase (COMT) were examined in MCF7 and in MCF10A‐derived cell lines representing a lineage cell culture model for breast cancer progression. Relative to MCF7, MCF10A‐derived cells expressed low levels of ERα but comparable levels of ERβ. In benign parental MCF10A breast epithelial cells, SULT1E1 mRNA was induced in confluent relative to subconfluent cell cultures. Proestrogenic 17βHSD1 mRNA was expressed in all of the MCF10A lineage cell lines while 17βHSD2 mRNA was most abundant in MCF10A cells. CYP1B1, SULT1A1 and SULT2B1 were expressed in MCF7 cells, while STS and COMT were widely detected across cell lines. Treatment with the potent histone deacetylase inhibitor trichostatin A (TSA) induced SULT1E1, SULT2B1 and CYP19 mRNA, but suppressed CYP1B1, STS, COMT, 17βHSD1 and 17βHSD2 mRNA in MCF10A lineage cell lines. In MCF7 cells, TSA treatment suppressed ERα, CYP1B1, STS, COMT, SULT1A1, and SULT2B1 but induced ERβ, CYP19 and SULT2A1 mRNA expression. The results indicate that relative to ER‐positive MCF7 cells, key determinants of breast estrogen metabolism are differentially regulated during neoplastic progression. Supported by ES05823 and ES06636.

Expression of estrogenicity genes in a lineage cell culture model of human breast cancer progression

TaqMan Gene Expression assays were used to profile the mRNA expression of estrogen receptor (ERalpha and ERbeta) and estrogen metabolism enzymes including cytosolic sulfotransferases (SULT1E1, SULT1A1, SULT2A1, and SULT2B1), steroid sulfatase (STS), aromatase (CYP19), 17beta-hydroxysteroid dehydrogenases (17betaHSD1 and 2), CYP1B1, and catechol-O-methyltransferase (COMT) in an MCF10A-derived lineage cell culture model for basal-like human breast cancer progression and in ERalpha-positive luminal MCF7 breast cancer cells. Low levels of ERalpha and ERbeta mRNA were present in MCF10A-derived cell lines. SULT1E1 mRNA was more abundant in confluent relative to subconfluent MCF10A cells, a non-tumorigenic proliferative breast disease cell line. SULT1E1 was also expressed in preneoplastic MCF10AT1 and MCF10AT1K.cl2 cells, but was markedly repressed in neoplastic MCF10A-derived cell lines as well as in MCF7 cells. Steroid-metabolizing enzymes SULT1A1 and SULT2B1 were only expressed in MCF7 cells. STS and COMT were widely detected across cell lines. Pro-estrogenic 17betaHSD1 mRNA was most abundant in neoplastic MCF10CA1a and MCF10DCIS.com cells, while 17betaHSD2 mRNA was more prominent in parental MCF10A cells. CYP1B1 mRNA was most abundant in MCF7 cells. Treatment with the histone deacetylase inhibitor trichostatin A (TSA) induced SULT1E1 and CYP19 mRNA but suppressed CYP1B1, STS, COMT, 17betaHSD1, and 17betaHSD2 mRNA in MCF10A lineage cell lines. In MCF7 cells, TSA treatment suppressed ERalpha, CYP1B1, STS, COMT, SULT1A1, and SULT2B1 but induced ERbeta, CYP19 and SULT2A1 mRNA expression. The results indicate that relative to the MCF7 breast cancer cell line, key determinants of breast estrogen metabolism are differentially regulated in the MCF10A-derived lineage model for breast cancer progression.

3,3´-Diindolylmethane and Genistein Decrease the Adverse Effects of Estrogen in LNCaP and PC-3 Prostate Cancer Cells

Evidence suggests that 17 β-estradiol (E2) contributes to the risk of prostate cancer (PCa), whereas the phytochemicals genistein from soy and 3,3´-diindolylmethane (DIM), derived from indole-3-carbinol in cruciferous vegetables, decrease the risk of PCa. This study examined the potential of these phytochemicals to reduce the adverse effects of E2 on PCa. In LNCaP PCa cells (E2 sensitive), DIM decreased E2-induced proliferation. Genistein increased proliferation at low concentrations and decreased proliferation at higher concentrations; DIM abolished the increased proliferation by genistein. The E2 stimulation in LNCaP cells was consistent with dependence on the androgen receptor, as evidenced by the inhibition of E2-induced proliferation with the antiandrogen casodex, E2 stimulation of an androgen response element luciferase reporter, and E2 stimulation of prostate-specific antigen (PSA) protein expression. Both genistein and DIM abrogated the E2 stimulation of PSA. Genistein and DIM altered major E2 metabolism pathways in LNCaP and PC-3 (E2 insensitive) PCa cells by increasing the expression of the 2-hydoxylation enzyme cytochrome P450 1A1 (CYP1A1) and the O-methylating enzyme catechol-o-methyltransferase (COMT) as determined by real-time RT-PCR. The increase in COMT mRNA occurred only when the combination of DIM and genistein (15 μmol/L) was used. Quantitation by MS indicated increased 2-hydroxyestrogen and decreased 16α-hydroxyestrone, a result that should result in less estrogenicity and increased amounts of the anticancer metabolite 2-methoxyestrone. We conclude that DIM and genistein decrease the effects of E2 that have the potential to promote PCa.

COMT Genotype Influences the Effect of Alcohol on Blood Pressure: Results From the COMBINE Study

Heavy drinking can cause chronic hypertension, possibly due to effects on the autonomic nervous system. Catechol- O-methyltransferase (COMT) inactivates catecholamines, and a G to A substitution in codon 108 in the soluble COMT mRNA (or codon 158 in the membrane-bound form) substitutes methionine for valine and alters enzyme activity. We evaluated the association of COMT genotype at this locus with blood pressure (BP) in 839 alcohol-dependent individuals before and during participation in an alcoholism treatment trial. Hierarchical linear models were used to account for within-subject correlation on repeated BP measurements, and findings were adjusted for age, gender, ethnicity, alcohol use, body mass index, current smoking, hypertension history, and study site. Relative to those with the val-val genotype, those with the met-met genotype had higher adjusted systolic (+4.9 mm Hg, P < 0.01) and diastolic (+3.2 mm Hg, P < 0.01) BP at baseline. Those with the val-met genotype did not significantly differ from the val-val genotype. Changes in BP between baseline and 4 weeks of alcohol treatment also differed by genotype. Relative to the val-val genotype, the met-met genotype had a greater reduction in adjusted systolic pressure (-3.9 mm Hg, P < 0.01) and diastolic pressure (-2.8 mm Hg, P < 0.01). Corresponding relative reductions for the val-met genotype were -2.2 mm Hg systolic (P = 0.070) and -1.5 mm Hg diastolic (P < 0.05). Findings suggest that alcohol-induced BP elevation may be related to the effects of catecholamines and their genetically determined inactivation.

Soy isoflavones decrease the catechol-O-methyltransferase-mediated inactivation of 4-hydroxyestradiol in cultured MCF-7 cells

The tissue concentrations of the female sex hormone 17beta-estradiol (E2) and its reactive catechol metabolites such as 4-hydroxyestradiol (4-HO-E2) play important roles in hormonal carcinogenesis. They are influenced by the activity of local enzymes involved in the metabolic activation and inactivation of E2. In the mammary gland, catechol estrogens are predominately inactivated by catechol-O-methyltransferase (COMT). Food supplements containing the soy isoflavones genistein and daidzein are consumed because they are believed to protect from breast cancer; however, this proposed benefit is controversial. The aim of the present study was to investigate the influence of soy isoflavones on the gene expression and activity of COMT in cultured human mammary adenocarcinoma MCF-7 cells. Levels of COMT messenger RNA (mRNA) were determined by reverse transcription/competitive polymerase chain reaction and COMT activity was determined by high-performance liquid chromatography analysis of the methylation products of both the model substrate quercetin and the physiological relevant substrate 4-HO-E2. Our study demonstrates for the first time that soy isoflavones at hormonally active concentrations cause a significant reduction of both COMT mRNA levels and COMT activity as well as of the methylation of 4-HO-E2. Experiments using the estrogen receptor (ER) antagonist ICI 182,780 support a role of the ER in the isoflavone-induced down-regulation of COMT expression. Thus, this study not only demonstrates that hormonally active concentrations of soy isoflavones inhibit the detoxification of catechols in this human breast cancer cell line but also implies that diet might influence COMT activity to a greater extent than heretofore recognized.