Sulfotransferase 1A1 (SULT1A1) polymorphism and susceptibility to primary brain tumors

Identifying BMI-associated genes via a genome-wide multi-omics integrative approach using summary data

OBJECTIVE

This study aims to identify BMI-associated genes by integrating aggregated summary information from different omics data.

METHODS

We conducted a meta-analysis to leverage information from a genome-wide association study (n = 339 224), a transcriptome-wide association study (n = 5619), and an epigenome-wide association study (n = 3743). We prioritized the significant genes with a machine learning-based method, netWAS, which borrows information from adipose tissue-specific interaction networks. We also used the brain-specific network in netWAS to investigate genes potentially involved in brain-adipose interaction.

RESULTS

We identified 195 genes that were significantly associated with BMI through meta-analysis. The netWAS analysis narrowed down the list to 21 genes in adipose tissue. Among these 21 genes, six genes, including FUS, STX4, CCNT2, FUBP1, NDUFS3, and RAPSN, were not reported to be BMI-associated in PubMed or GWAS Catalog. We also identified 11 genes that were significantly associated with BMI in both adipose and whole brain tissues.

CONCLUSION

This study integrated three types of omics data and identified a group of genes that have not previously been reported to be associated with BMI. This strategy could provide new insights for future studies to identify molecular mechanisms contributing to BMI regulation.

Genetic polymorphism of Arg213His variant in the SULT1A1 gene is associated with reduced susceptibility to lung cancer in North Indian population

Sulfotransferases (SULTs) are phase II detoxification enzymes that is involved in the biotransformation of many compounds including tobacco carcinogens. A polymorphism in the SULT1A1 (Arg²¹³His) gene results in reduced enzyme activity.We investigated the association between the SULT1A1 (Arg²¹³/His) genotype and lung cancer (LC). This case-control study comprised of 550 cases and controls, matched on age, gender and smoking status.The variant genotype exhibited no association with LC risk, even after stratification on basis of histological subtypes. Male LC patients carrying the variant His²¹³ allele (p = 0.02) did not exhibit an increased risk towards LC. Smokers harbouring the Arg/His genotype did demonstrate a reduced risk towards LC (AOR = 0.70; p = 0.019). Furthermore, the LC subjects who were heavy smokers and harbouring the Arg/His genotype (AOR = 0.28; p = 0.019) did not show a genetic predisposition towards LC susceptibility. The subjects who smoked pack years of above 40 and carrying the His/His (AOR = 0.28; p = 0.036) genotype were found to have a reduced risk for LC. Furthermore, 473 subjects were analysed in regards to overall survival, wherein the His/His genotype exhibited better OS than Arg/Arg genotype (11.30 vs. 8.07 months).This study provides evidence of no genetic predisposition towards LC risk associated with SULT1A1 Arg²¹³His polymorphism in relation to tobacco smoking.

SULT genetic polymorphisms: physiological, pharmacological and clinical implications

INTRODUCTION

Cytosolic sulfotransferases (SULTs)-mediated sulfation is critically involved in the metabolism of key endogenous compounds, such as catecholamines and thyroid/steroid hormones, as well as a variety of drugs and other xenobiotics. Studies performed in the past three decades have yielded a good understanding about the enzymology of the SULTs and their structural biology, phylogenetic relationships, tissue/organ-specific/developmental expression, as well as the regulation of the SULT gene expression. An emerging area is related to the functional impact of the SULT genetic polymorphisms.

AREAS COVERED

The current review aims to summarize our current knowledge about the above-mentioned aspects of the SULT research. An emphasis is on the information concerning the effects of the polymorphisms of the SULT genes on the functional activity of the SULT allozymes and the associated physiological, pharmacological, and clinical implications.

EXPERT OPINION

Elucidation of how SULT SNPs may influence the drug-sulfating activity of SULT allozymes will help understand the differential drug metabolism and eventually aid in formulating personalized drug regimens. Moreover, the information concerning the differential sulfating activities of SULT allozymes toward endogenous compounds may allow for the development of strategies for mitigating anomalies in the metabolism of these endogenous compounds in individuals with certain SULT genotypes.

Genotypes of CYP1A1, SULT1A1 and SULT1A2 and risk of squamous cell carcinoma of esophagus: outcome of a case-control study from Kashmir, India

Studies on associations of various polymorphism in xenobiotic metabolizing genes with different cancers including esophageal squamous cell carcinoma (ESCC) are mixed and inconclusive. To evaluate the association of CYP1A1*4, SULT1A1*2 and SULT1A2*2 genotypes with ESCC risk and their modifying effects on different risk factors of ESCC, we conducted a case-control study in Kashmir, India, an area with relative high incidence of ESCC. We recruited 404 histopathologically confirmed ESCC cases, and equal number of controls, individually matched for sex, age and district of residence to respective case. Information was obtained on various dietary, lifestyle and environmental factors in face-to-face interviews, using a structured questionnaire, from each subject. Genotypes were analyzed by polymerase chain reaction, restriction fragment length polymorphism and direct sequencing. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). A higher risk was observed in the subjects who harbored variant genotype of CYP1A1*4 (OR = 2.06; 95% CI: 1.28-3.32); and the risk was further enhanced in ever smokers (OR = 3.47; 95% CI: 1.62-7.42), adobe dwellers (OR = 6.71; 95% CI: 3.02-14.89), and biomass fuel users (OR = 5.11; 95% CI: 1.34-19.50). We did not find any significant differences in the polymorphic variants of SULT1A1*2 and SULT1A2*2 between cases and controls. The study indicates that, unlike SULT1A1*2 and SULT1A2*2, the polymorphism of CYP1A1*4 is associated with ESCC risk. However, replicative studies with larger sample size are needed to substantiate our findings.

Expression of sulfotransferase SULT1A1 in cancer cells predicts susceptibility to the novel anticancer agent NSC-743380

The small molecule anticancer agent NSC-743380 modulates functions of multiple cancer-related pathways and is highly active in a subset of cancer cell lines in the NCI-60 cell line panel. It also has promising in vivo anticancer activity. However, the mechanisms underlying NSC-743380's selective anticancer activity remain uncharacterized. To determine biomarkers that may be used to identify responders to this novel anticancer agent, we performed correlation analysis on NSC-743380's anticancer activity and the gene expression levels in NCI-60 cell lines and characterized the functions of the top associated genes in NSC-743380–mediated anticancer activity. We found sulfotransferase SULT1A1 is causally associated with NSC-743380's anticancer activity. SULT1A1 was expressed in NSC-743380–sensitive cell lines but was undetectable in resistant cancer cells. Ectopic expression of SULT1A1 in NSC743380 resistant cancer cells dramatically sensitized the resistant cells to NSC-743380. Knockdown of the SULT1A1 in the NSC-743380 sensitive cancer cell line rendered it resistance to NSC-743380. The SULT1A1 protein levels in cell lysates from 18 leukemia cell lines reliably predicted the susceptibility of the cell lines to NSC-743380. Thus, expression of SULT1A1 in cancer cells is required for NSC-743380's anticancer activity and can be used as a biomarker for identification of NSC-743380 responders.

SULT1A1 genetic polymorphisms and the association between smoking and oral cancer in a case-control study in Brazil

INTRODUCTION

Oral cancer is a public health problem worldwide, being tobacco and alcohol consumption their main risk factors. Sulfotransferase (SULT) 1A1 (encoded by SULT1A1) is involved in procarcinogens metabolism, such as polycyclic aromatic hydrocarbons (PAHs) present in tobacco smoke.

OBJECTIVE

The aim of this study was to explore the magnitude of association between SULT1A1 gene Arg(213)His polymorphism and oral cancer, and to explore the interaction between such polymorphism and smoking.

METHODS

A hospital-based case-control study was carried out in Rio de Janeiro, Brazil, during 1999-2002. Epidemiological data and biological samples were obtained from 202 oral cancer patients and 196 sex and age-frequency matched controls without cancer antecedents.

RESULTS

No association was observed between Arg(213)His SULT1A1 polymorphism and oral cancer risk in overall analysis (OR = 1.06, 95% CI = 0.71-1.57). The magnitude of association between cigarette smoking and oral cancer was higher in individuals with a SULT1A1(*)1 isoform (wild type, genotype Arg/Arg) (OR = 10.19, 95% CI = 3.90-26.61) than in those with at least one SULT1A1(*)2 allele (genotypes Arg/His + His/His) (OR = 4.50, 95% CI =2.09-9.69).

CONCLUSION

Our results suggest that Arg(213)His SULT1A1 polymorphism may modulate the association between smoking and oral cancer. However, this association needs to be replicated in other studies: due to modest number of cases and controls, the role of chance in the observed association cannot be ruled out.

Sulfotransferase 1A1 Arg(213)His polymorphism and prostate cancer risk

Sulfotransferase 1A1 (SULT1A1) is a member of the sulfotransferase family that plays an important role in the biotransformation of numerous carcinogenic and mutagenic compounds through sulfation. A transition, G to A at position 638, in the SULT1A1 gene, results in the Arg(213)His change. This single nucleotide polymorphism reduces the activity and thermostability of the SULT1A1 enzyme. In the present study, the relationship between the SULT1A1 Arg(213)His polymorphism and prostate cancer was investigated using PCR-RFLP. No significant difference in genotype and allele distribution was noted between the prostate cancer and control populations (P=0.072; P=0.099, respectively). The risk of prostate cancer in individuals carrying the SULT1A1(*)2 allele (His(213) allele) was determined by combining the SULT1A1(*)1/SULT1A1(*)2 (Arg/His(213)) and SULT1A1(*)2/SULT1A1(*)2 (His/His(213)) genotypes. No association was observed between SULT1A1 Arg(213)His polymorphism and prostate cancer incidence (P=0.24; OR, 1.36; 95% CI, 0.84-2.25). However, the His(213) allele was found to increase the risk of prostate cancer by 1.36-fold. In smoker and non-smoker populations, no significant relationship was determined between the prostate cancer and control population (P=0.45; P=0.34, respectively).

Phase II drug metabolizing enzymes

BACKGROUND

Phase II biotransformation reactions (also 'conjugation reactions') generally serve as a detoxifying step in drug metabolism. Phase II drug metabolising enzymes are mainly transferases. This review covers the major phase II enzymes: UDP-glucuronosyltransferases, sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases (mainly thiopurine S-methyl transferase and catechol O-methyl transferase). The focus is on the presence of various forms, on tissue and cellular distribution, on the respective substrates, on genetic polymorphism and finally on the interspecies differences in these enzymes.

METHODS AND RESULTS

A literature search using the following databases PubMed, Science Direct and EBSCO for the years, 1969-2010.

CONCLUSIONS

Phase II drug metabolizing enzymes play an important role in biotransformation of endogenous compounds and xenobiotics to more easily excretable forms as well as in the metabolic inactivation of pharmacologically active compounds. Reduced metabolising capacity of Phase II enzymes can lead to toxic effects of clinically used drugs. Gene polymorphism/ lack of these enzymes may often play a role in several forms of cancer.

Genetic polymorphisms of sulfotransferases (SULT1A1 and SULT1A2) in a Turkish population

Sulfotransferases (SULTs) play a significant role in the biotransformation of a variety of xenobiotics and endogenous compounds. SULTs are genetically polymorphic enzymes; to date, 12 human cytosolic SULT isoforms have been identified. This study investigated SULT1A1 and SULT1A2 gene polymorphism using a PCR-RFLP method (n = 303). The frequency of the SULT1A1*1 allele was 76.2% and SULT1A1*2 was 23.8%. The SULT1A1*3 allele could not be identified. The SULT1A2 frequencies were 69.2% (SULT1A2*1), 18.3% (SULT1A2*2), and 12.5% (SULT1A2*3). The SULT1A1 and SULT1A2 loci were in Hardy-Weinberg equilibrium (SULT1A1 χ² = 0.58, P = 0.44; SULT1A2 χ² = 7.28, P = 0.06). Linkage analysis indicated a close linkage between these two genes (χ² = 5.31, P < 0.01); therefore, the statistical hypothesis that SULT1A1 and SULT1A2 alleles are independently distributed was rejected. Additionally, a strongly positive linkage was detected between SULT1A1*2 and SULT1A2*2 alleles in this population (D' = 0.79, χ² = 33.33).

Molecular epidemiology of primary brain tumors

Although primary brain tumors (PBTs) are generally considered to be a multifactorial disorder, understanding the genetic basis and etiology of the disease is essential for PBT risk assessment. Understanding of the genetic susceptibility for PBT has come from studies of rare genetic syndromes, linkage analysis, family aggregation, early-onset pediatric cases, and mutagen sensitivity. There are currently no effective markers to assess biological dose of exposures and genetic heterogeneity. The priorities recently recommended by the Brain Tumor Epidemiology Consortium emphasized the need for expanding research in genetics and molecular epidemiology. In this article, we review the literature to identify molecular epidemiologic case-control studies of PBTs that were hypothesis-driven and focused on four hypothesized candidate pathways: DNA repair, cell cycle, metabolism, and inflammation. We summarize the results in terms of genetic associations of single nucleotide polymorphisms of these pathways. We also discuss future research directions based on available evidence and technologies, and conclude that high resolution whole genome approach with significantly large sample size could rapidly advance our understanding of the genetic etiology of PBTs. Literature searches were done on PubMed in March 2009 with the terms glioma, glioblastoma, brain tumor, association, and polymorphism, and we only reviewed English language publications.

Expression and localization of cytosolic sulfotransferase (SULT) 1A1 and SULT1A3 in normal human brain

Cytosolic sulfotransferases (SULTs) are a family of Phase II drug-metabolizing enzymes that catalyze the transfer of a sulfonate group from 3'-phosphoadenosine 5'-phosphosulfate to endogenous and xenobiotic compounds. Several SULT isoform messages have been detected in the human brain; however, protein expression patterns have not been characterized. Immunoblot analysis of the SULT1A1 and 1A3 isoforms was carried out with cytosolic fractions isolated from superior temporal gyrus, hippocampus, cerebellum, occipital pole, frontal pole, and temporal pole regions of normal adult human brains. SULT1A1 expression was highest in cytosolic fractions isolated from cerebellum, occipital, and frontal lobes, whereas, SULT1A3 expression was highest in cytosol from superior temporal gyrus, hippocampus, and temporal lobe. SULT1A1 and SULT1A3 immunoreactivities were found in both neurons and glial cells by immunohistochemical analysis in all brain regions studied. SULT1A1 is known to catalyze the metabolism of small phenols, whereas SULT1A3 sulfates catecholamine neurotransmitters. Because SULT1A1 and 1A3 have distinct substrate specificities, the differences in expression pattern and cellular localization of the SULT1A isoforms are probably associated with the distribution and function of their selective substrates in the different brain regions.

Case-control study and meta-analysis of SULT1A1 Arg213His polymorphism for gene, ethnicity and environment interaction for cancer risk

Cytosolic sulphotransferase SULT1A1 plays a dual role in the activation of some carcinogens and inactivation of others. A functional polymorphism leading to Arg²¹³His substitution (SULT1A1*2) affects its catalytic activity and thermostability. To study the association of SULT1A1*2 polymorphism with tobacco-related cancers (TRCs), a case–control study comprising 132 patients with multiple primary neoplasm (MPN) involving TRC and 198 cancer-free controls was carried out. One hundred and thirteen MPN patients had at least one cancer in upper aerodigestive tract including lung (UADT-MPN). SULT1A1*2 showed significant risk association with UADT-MPN (odds ratio (OR)=5.50, 95% confidence interval (CI): 1.09, 27.7). Meta-analysis was conducted combining the data with 34 published studies that included 11 962 cancer cases and 14 673 controls in diverse cancers. The SULT1A1*2 revealed contrasting risk association for UADT cancers (OR=1.62, 95% CI: 1.12, 2.34) and genitourinary cancers (OR=0.73, 95% CI: 0.58, 0.92). Furthermore, although SULT1A1*2 conferred significant increased risk of breast cancer to Asian women (OR=1.91, 95% CI: 1.08, 3.40), it did not confer increased risk to Caucasian women (OR=0.92, 95% CI: 0.71, 1.18). Thus risk for different cancers in distinct ethnic groups could be modulated by interaction between genetic variants and different endogenous and exogenous carcinogens.

Comparative analysis of microarray data identifies common responses to caloric restriction among mouse tissues

Caloric restriction has been extensively investigated as an intervention that both extends lifespan and delays age-related disease in mammals. In mice, much interest has centered on evaluating gene expression changes induced by caloric restriction (CR) in particular tissue types, but the overall systemic effect of CR among multiple tissues has been examined less extensively. This study presents a comparative analysis of microarray datasets that have collectively examined the effects of CR in 10 different tissue types (liver, heart, muscle, hypothalamus, hippocampus, white adipose tissue, colon, kidney, lung and cochlea). Using novel methods for comparative analysis of microarray data, detailed comparisons of the effects of CR among tissues are provided, and 28 genes for which expression response to CR is most shared among tissues are identified. These genes characterize common responses to CR, which consist of both activation and inhibition of stress-response pathways. With respect to liver tissue, transcriptional effects of CR exhibited surprisingly little overlap with those of aging, and a variable degree of overlap with the potential CR-mimetic drug resveratrol. These analyses shed light on the systemic transcriptional activity associated with CR diets, and also illustrate new approaches for comparative analysis of microarray datasets in the context of aging biology.