Cyclooxygenase-2 gene polymorphisms in an Australian population: association of the -1195G > A promoter polymorphism with mild asthma

Deep sequencing of prostaglandin-endoperoxide synthase (PTGE) genes reveals genetic susceptibility for cross-reactive hypersensitivity to NSAID

BACKGROUND AND PURPOSE

Cross-reactive hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs) is a relatively common adverse drug event caused by two or more chemically unrelated drugs and that is attributed to inhibition of the COX activity, particularly COX-1. Several studies investigated variations in the genes coding for COX enzymes as potential risk factors. However, these studies only interrogated a few single nucleotide variations (SNVs), leaving untested most of the gene sequence.

EXPERIMENTAL APPROACH

In this study, we analysed the whole sequence of the prostaglandin-endoperoxide synthase genes, PTGS1 and PTGS2, including all exons, exon-intron boundaries and both the 5' and 3' flanking regions in patients with cross-reactive hypersensitivity to NSAIDs and healthy controls. After sequencing analysis in 100 case-control pairs, we replicated the findings in 540 case-control pairs. Also, we analysed copy number variations for both PTGS genes.

KEY RESULTS

The most salient finding was the presence of two PTGS1 single nucleotide variations, which are significantly more frequent in patients than in control subjects. Patients carrying these single nucleotide variations displayed a significantly and markedly lower COX-1 activity as compared to non-carriers for both heterozygous and homozygous patients.

CONCLUSION AND IMPLICATIONS

Although the risk single nucleotide variations are present in a small proportion of patients, the strong association observed and the functional effect of these single nucleotide variations raise the hypothesis of genetic susceptibility to develop cross-reactive NSAID hypersensitivity in individuals with an impairment in COX-1 enzyme activity.

Genetic polymorphisms of pharmacogenomic VIP variants in the Lisu population of southwestern China: A cohort study

Pharmacogenomic studies of different ethnic or racial groups have been used to develop personalized therapies specific to subjects. This study aimed to identify the distribution differences of very important pharmacogenetic (VIP) variants between the Lisu population from southwestern China and other ethnic groups.Eighty VIP variants in 37 genes were selected from the pharmacogenomic knowledge base (PharmGKB), and compared with genotype data of the Lisu population then compared with other 11 populations from the HapMap dataset and previously published data including Miao, Li, Deng, Sherpa, Lhoba, Tibetan, Kirghiz, Tajik, Mongol, Shaanxi Han ethnic, and Uygur populations.VDR rs1540339, MTHFR rs1801131, P2RY1 rs701265, and PTGS2 rs689466 were significantly different between Lisu and 11 HapMap populations. ANKK1 rs1800497 was the least statistical significant locus among selected single nucleotide polymorphisms. In addition, genetic background of Lisu was strongly closest to Shaanxi Han ethnic cohort, and followed by Chinese in metropolitan Denver population based on population structure and F-statistics analyses.Our results showed significant interethnic differences between Lisu and other populations, which will give useful information for prospective studies and better individualized treatments.

Genetic polymorphisms of pharmacogenomic VIP variants in the Yi population from China

INTRODUCTION

Drug response and target therapeutic dosage are different among individuals. The variability is largely genetically determined. With the development of pharmacogenetics and pharmacogenomics, widespread research have provided us a wealth of information on drug-related genetic polymorphisms, and the very important pharmacogenetic (VIP) variants have been identified for the major populations around the world whereas less is known regarding minorities in China, including the Yi ethnic group. Our research aims to screen the potential genetic variants in Yi population on pharmacogenomics and provide a theoretical basis for future medication guidance.

MATERIALS AND METHODS

In the present study, 80 VIP variants (selected from the PharmGKB database) were genotyped in 100 unrelated and healthy Yi adults recruited for our research. Through statistical analysis, we made a comparison between the Yi and other 11 populations listed in the HapMap database for significant SNPs detection. Two specific SNPs were subsequently enrolled in an observation on global allele distribution with the frequencies downloaded from ALlele FREquency Database. Moreover, F-statistics (Fst), genetic structure and phylogenetic tree analyses were conducted for determination of genetic similarity between the 12 ethnic groups.

RESULTS

Using the χ2 tests, rs1128503 (ABCB1), rs7294 (VKORC1), rs9934438 (VKORC1), rs1540339 (VDR) and rs689466 (PTGS2) were identified as the significantly different loci for further analysis. The global allele distribution revealed that the allele "A" of rs1540339 and rs9934438 were more frequent in Yi people, which was consistent with the most populations in East Asia. F-statistics (Fst), genetic structure and phylogenetic tree analyses demonstrated that the Yi and CHD shared a closest relationship on their genetic backgrounds. Additionally, Yi was considered similar to the Han people from Shaanxi province among the domestic ethnic populations in China.

CONCLUSIONS

Our results demonstrated significant differences on several polymorphic SNPs and supplement the pharmacogenomic information for the Yi population, which could provide new strategies for optimizing clinical medication in accordance with the genetic determinants of drug toxicity and efficacy.

Angiogenesis-related genes and thalidomide teratogenesis in humans: an approach on genetic variation and review of past in vitro studies

Thalidomide embryopathy (TE) has affected more than 10,000 babies worldwide. The hypothesis of antiangiogenesis as the teratogenic mechanism of thalidomide has been investigated in several experimental models; but, in humans, it has only been accessed by in vitro studies. Here, we hypothesized the effect of thalidomide upon angiogenesis-related molecules or proteins, previously identified in human embryonic cells, through the in silico STRING-tool. We also investigated ten polymorphisms in angiogenesis-related genes in 38 Brazilian TE individuals and 136 non-affected Brazilians. NOS2, PTGS2, and VEGFA polymorphisms were chosen for genotyping. The STRING-tool suggested nitric oxide and β-catenin as the central angiogenesis-related molecules affected by thalidomide's antiangiogenic property. We did not identify a significant difference of allelic, genotypic or haplotypic frequencies between the groups. We could not predict a risk allele or a protective one for TE in NOS2, PTGS2, or VEGFA, although other genes should be analyzed in larger samples. The role of nitric oxide and β-catenin must be further evaluated, regarding thalidomide teratogenesis complex etiology.

Genetic variants in TNFα, TGFB1, PTGS1 and PTGS2 genes are associated with diisocyanate-induced asthma

Diisocyanates are the most common cause of occupational asthma, but risk factors are not well defined. A case-control study was conducted to investigate whether genetic variants in inflammatory response genes (TNFα, IL1α, IL1β, IL1RN, IL10, TGFB1, ADAM33, ALOX-5, PTGS1, PTGS2 and NAG-1/GDF15) are associated with increased susceptibility to diisocyanate asthma (DA). These genes were selected based on their role in asthmatic inflammatory processes and previously reported associations with asthma phenotypes. The main study population consisted of 237 Caucasian French Canadians from among a larger sample of 280 diisocyanate-exposed workers in two groups: workers with specific inhalation challenge (SIC) confirmed DA (DA(+), n = 95) and asymptomatic exposed workers (AW, n = 142). Genotyping was performed on genomic DNA, using a 5' nuclease PCR assay. After adjusting for potentially confounding variables of age, smoking status and duration of exposure, the PTGS1 rs5788 and TGFB1 rs1800469 single nucleotide polymorphisms (SNP) showed a protective effect under a dominant model (OR = 0.38; 95% CI = 0.17, 0.89 and OR = 0.38; 95% CI = 0.18, 0.74, respectively) while the TNFα rs1800629 SNP was associated with an increased risk of DA (OR = 2.08; 95% CI = 1.03, 4.17). Additionally, the PTGS2 rs20417 variant showed an association with increased risk of DA in a recessive genetic model (OR = 6.40; 95% CI = 1.06, 38.75). These results suggest that genetic variations in TNFα, TGFB1, PTGS1 and PTGS2 genes contribute to DA susceptibility.

Association between cyclooxygenase-2 gene polymorphisms and head and neck squamous cell carcinoma risk

Cyclooxygenase-2 (COX-2) is an inducible enzyme that catalyzes prostaglandins through inflammatory response, which may be involved in autoimmune diseases and cancer pathogenesis. Two potentially functional genetic single-nucleotide polymorphisms (COX-2 -1195G>A and 8473T>C) were supposed to contribute to head and neck squamous cell carcinoma (HNSCC) susceptibility. The aim of this study was to determine the association of these polymorphisms with HNSCC susceptibility in a Chinese Han population. In this study, 2 SNPs were genotyped by TaqMan methods in a patient-control study including 260 patients with HNSCC and 1047 cancer-free controls in a Chinese Han population. We found significant difference in the frequency of alcohol consumption between the patients with HNSCC and controls (P < 0.001), but the genotype frequencies of the 2 polymorphisms were not significantly different between the patients and controls. Further stratified analysis indicated that none of the genotypes were associated with increased risk for HNSCC. This research indicated that the COX-2 -1195G>A and 8473T>C polymorphisms may not be involved in the development of HNSCC in the Chinese Han population. However, further perspective studies are warranted to test these findings and further investigate the potential interactions involving the COX-2 polymorphism and HNSCC.

The VEGFR2, COX-2 and MMP-2 polymorphisms are associated with clinical outcome of patients with inoperable non-small cell lung cancer

Certain common inherited variations in genes involved in tumor angiogenesis, progression and metastasis may contribute to cancer therapy outcome and prognosis by altering the gene expression and protein activity. In this report, we examined the effect of functional polymorphisms in MMP-1, MMP-2, MMP-3, VEGF, VEGFR2, FGFR4 and COX-2 genes on overall (OS) and progression-free survival (PFS) of 350 Caucasian patients with inoperable non-small cell lung cancer (NSCLC). The results of multivariate analysis indicated that VEGFR2 -906C and COX-2 -1195G alleles were strongly associated with poor OS and PFS (p = 0.002 and 0.015, respectively, for OS; p = 0.009 and 0.015, respectively, for PFS), while MMP-2 -1306 T allele carriers had significantly reduced PFS (p = 0.010). Moreover, an increased risk of death and progression was significantly associated with the number of adverse alleles for VEGFR2/COX-2 (p = 0.0005 for OS and 0.0006 for PFS in >1 adverse allele carriers) and VEGFR2/COX-2/MMP-2 combinations (p = 0.0003 for OS and 0.0001 for PFS in patients with >2 adverse alleles). Finally, VEGFR2 TC/CC, COX-2 AG/GG and MMP-2 CT/TT genotypes as well as "at risk" allele combinations were identified as independent predictors of unfavorable OS and PFS in the group. In conclusion, the data suggest that selected VEGFR2, COX-2 and MMP-2 polymorphisms may be potential prognostic markers in unresectable NSCLC treated with radiotherapy with or without chemotherapy, although further validation studies are warranted to confirm our observations.

Pharmacogenomics of cyclooxygenases

Cyclooxygenases (COX-1 and COX-2) are key enzymes in several physiopathological processes. Many adverse drugs reactions to NSAIDs are attributable to COX-inhibition. The genes coding for these enzymes (PTGS1 and PTGS2) are highly variable, and variations in these genes may underlie the risk of developing, or the clinical evolution of, several diseases and adverse drug reactions. We analyze major variations in the PTGS1 and PTGS2 genes, allele frequencies, functional consequences and population genetics. The most salient clinical associations of PTGS gene variations are related to colorectal cancer and stroke. In many studies, the SNPs interact with NSAIDs use, dietary or environmental factors. We provide an up-to-date catalog of PTGS clinical associations based on case–control studies and genome-wide association studies, and future research suggestions.

Cyclooxygenase-2 genetic variants influence intratumoral infiltration of Foxp3-positive regulatory T cells in non-small cell lung cancer

The immune microenvironment of primary tumors has been reported to be a prognostic factor. We previously reported that the tumor-infiltrating regulatory T cell (Treg) count was positively correlated with the intratumoral cyclooxygenase-2 (COX-2) expression level and was associated with a poor survival among patients with non-small cell lung cancer (NSCLC). Recently, numerous single nucleotide polymorphisms (SNPs) in the COX-2 gene have been identified, and these SNPs may contribute to differential gene expression and enzyme activity levels. However, whether COX-2 genetic variants influence the functions of COX-2 in NSCLC remains unclear. Eighty NSCLC patients who underwent a complete resection at our institute were enrolled. We extracted DNA from the peripheral blood and identified five different COX-2 SNPs. The correlations between the COX-2 SNPs and the expression levels of COX-2, Tregs and Ki-67 were studied. The prognostic significance of the COX-2 SNPs was also evaluated. COX-2 SNPs were not correlated with the expression of COX-2. However, for the COX-2 -1195G/A polymorphism, the AA genotype group had a significantly higher Treg score. Furthermore, the AA group had a significantly higher Treg score regardless of the COX-2 expression level. The COX-2 -1195AA genotype group tended to have a shorter disease-free survival period than the GA/GG group. In conclusion, the COX-2 -1195G/A polymorphism influences the infiltration of Tregs into NSCLC, and the COX-2 SNP factor may be a prognostic factor reflecting Treg infiltration in NSCLC.

Relationships of COX2 and MMP12 genetic polymorphisms with chronic obstructive pulmonary disease risk: a meta-analysis

We performed the present meta-analysis in an attempt to confirm the correlation of genetic polymorphisms in the COX2 and MMP12 genes with the susceptibility to chronic obstructive pulmonary disease (COPD). We searched English database such as PubMed, CISCOM, CINAHL, Web of Science, Google Scholar and several Chinese database for meta-analysis. There were no specific language restrictions. Two investigators systematically extracted relevant data within those included studies. Crude ORs with its corresponding 95 % CI were calculated. STATA 12.0 software was adopted for statistical analysis. The impact of COX2 and MMP12 genetic polymorphisms on the pathogenesis of COPD was investigated in the current study with a total of 10 case-control studies, which includes 1,751 COPD patients and 2,472 healthy subjects. Four common polymorphisms, including rs689466 G > A and rs20417 G > C in the COX2 gene, rs652438 A > G and rs2276109 A > G were evaluated in the MMP12 gene. Pooled OR of the present studies and results showed that the frequency of COX2 rs20417 polymorphism was prevalent in COPD patients than those of healthy subjects (C allele vs. G allele OR = 1.33, 95 % CI 1.06-1.67, P = 0.014; GC + CC vs. GG OR = 1.86, 95 % CI 1.07-3.24, P = 0.029; respectively). However, we found no significant correlation between COX2 rs689466 polymorphism and the risk of COPD (all P > 0.05). Furthermore, our meta-analysis illustrated that individuals with MMP12 rs652438 polymorphism had significantly increased risk of developing COPD (G allele vs. A allele OR = 1.62, 95 % CI 1.08-2.42, P = 0.020; AG + GG vs. AA OR = 2.14, 95 % CI 1.12-4.09, P = 0.021; respectively). Nevertheless, no positive relation was detected between MMP12 rs2276109 variant and the risk of COPD. Our meta-analysis indicates that COX2 and MMP12 genetic polymorphisms may be strongly implicated in the development of COPD, especially for the COX2 rs20417 and MMP12 rs652438 polymorphisms. Thus, COX2 and MMP12 genetic polymorphisms could potentially be utilized as helpful biomarkers for early diagnosis of COPD.

Genetic polymorphism in cyclooxygenase-2 promoter affects hepatic inflammation and fibrosis in patients with chronic hepatitis C

Cyclooxygenase (COX)-2 is involved in inflammation, anti-apoptosis and carcinogenesis. The -1195GG genotype of single nucleotide polymorphism (SNP) in COX-2 promoter was associated with low platelet counts in patients with chronic hepatitis C. Polymorphism of patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene (rs738409 C>G) have been reported to be associated with cirrhosis, and the major genotype of SNPs near interleukin (IL)28B are related to viral clearance. The present study was designed to assess the contribution of these SNPs to disease progression in patients with chronic hepatitis C. The study enrolled 220 Japanese patients with chronic hepatitis C. Three SNPs, -1195 COX-2, PNPLA3 and IL28B (rs8099917), were genotyped in order to analyze their association with hepatic fibrosis and inflammation. The -1195GG genotype in COX-2 was associated with advanced fibrosis and higher levels of inflammation in the liver tissues. The major genotype of IL28B was also associated with advanced fibrosis, but the polymorphism of PNPLA3 was neither associated with fibrosis nor inflammation. Multivariate analysis showed that -1195GG in COX-2 is an independent factor associated with advanced fibrosis, while the major genotype of IL28B and HCV genotype 2 were other independent factors. In conclusion, the -1195GG genotype in COX-2 is a genetic marker for liver disease progression, while the PNPLA3 genotypes are not associated with disease progression in Japanese patients with chronic hepatitis C.

Cyclooxygenase-2 polymorphisms and the risk of gastric cancer in various degrees of relationship in the Chinese Han population

A number of studies have shown that cyclooxygenase-2 (COX-2) gene polymorphisms were associated with gastric cancer. However, the results from different research groups have not been consistent. The present study aimed to investigate the association between polymorphisms of the cyclooxygenase-2 promoter region (-1195G>A, -765G>C) and gastric cancer patients with various degrees of relationship in the Chinese Han population. COX-2-1195G>A and COX-2-765G>C polymorphisms in 296 gastric cancer patients and 319 control family members were genotyped using polymerase chain reaction-restriction fragment length polymorphism. An increased risk of gastric cancer was observed in subjects with the COX-2-1195AA genotype (OR=2.03; 95% CI, 1.27-3.22), and the association strength decreased as the degree of relationship decreased. Stratification analysis revealed that the OR value of COX-2-1195AA genotype and A carriers exhibited synergy with Helicobacter pylori (H. pylori) infection (AA genotype: OR=2.96; 95% CI, 1.57-5.58; A carriers: OR=2.04; 95% CI, 1.18-3.52). No significant difference was found in each genotype of COX-2-765G>C between gastric cancer patients and control family members, as well as gastric cancer patients with various degrees of relationship. Our study demonstrated that the polymorphism of COX-2-1195AA genotype may be a risk factor for gastric cancer patients with various degrees of relationship among the Chinese Han population. H. pylori infection therefore may enhance the risk of gastric cancer in individuals with the COX-2-1195 AA genotype.

Functional polymorphisms of cyclooxygenase-2 gene and risk for hepatocellular carcinoma

Cyclooxygenase-2 (COX-2) influences carcinogenesis through immune response suppression, apoptosis inhibition, regulation of angiogenesis and tumor cell invasion, and metastasis. It is now well established that COX-2 is overexpressed in many premalignant, malignant, and metastatic cancers, including hepatocellular carcinoma (HCC). DNA sequence variations in the COX-2 gene may lead to altered COX-2 production and/or activity, and so they cause inter-individual differences in the susceptibility to HCC. Functional coding region polymorphisms -1195A>G (rs689466), -765G>C (rs20417), and +8473T>C (rs5275) in the COX-2 gene have recently been shown to be associated with several human cancers but their association with HCC has yet to be investigated. We used hospital-based case-control study to assess the hypothesis that the functional COX-2 variation may affect individual susceptibility to the HCC. COX-2 polymorphisms were investigated in 129 confirmed subjects with HCC and 129 cancer-free control subjects matched on age, gender, smoking, and alcohol consumption using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The distribution of the COX-2 -1195A>G and +8473T>C genotypes were not significantly different between HCC cases and control. However, proportion of the COX-2 -765CC genotype which leads to a 30% reduction of the COX-2 promoter activity was significantly lower in patients with HCC (3.1%) when compared to control subjects (11.6%) (P < 0.05). Logistic regression analyses revealed that the COX-2 -765G>C variant genotype (-765CC) was associated with a significantly decreased risk of HCC compared with the -765GG wild-type homozygotes [P < 0.05, odds ratio (OR) = 0.25, 95% confidence interval (CI) = 0.08-0.79]. Our results suggest for the first time that the -765CC genotype of COX-2 -765G>C polymorphism, causing lower COX-2 gen expression, is a genetic protective factor for HCC. However, because this is the first report concerning the COX-2 -1195A>G, -765G>C, and +8473T>C polymorphisms and the risk of HCC, independent studies are needed to validate our findings.

Developments in the field of allergy in 2008 through the eyes of Clinical & Experimental Allergy

In 2008, many thousands of articles were published on the subject of allergic disease with over 200 reviews, editorials and original papers in Clinical & Experimental Allergy alone. These represent a considerable amount of data and even the most avid reader could only hope to assimilate a small fraction of this knowledge. There is therefore a pressing need for the key messages that emerge from a journal such as Clinical & Experimental Allergy to be summarized by experts in the field in a form that highlights the significance of the developments and sets them in the context of important findings in the field published in other journals. This also has the advantage of making connections between new data in conditions such as asthma, where articles often appear in different sections of the journal. As can be seen from this review, the body of work is diverse both in terms of the disease of interest and the discipline that has been used to investigate it. However, taken as a whole, we hope that the reader will gain a flavour of where the field is mature, where there remain controversies and where the cutting edge is leading.