Cyclooxygenase polymorphisms in gastric and colorectal carcinogenesis: are conclusive results available?

Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report

Helicobacter pyloriInfection is formally recognised as an infectious disease, an entity that is now included in the International Classification of Diseases 11th Revision. This in principle leads to the recommendation that all infected patients should receive treatment. In the context of the wide clinical spectrum associated with Helicobacter pylori gastritis, specific issues persist and require regular updates for optimised management.The identification of distinct clinical scenarios, proper testing and adoption of effective strategies for prevention of gastric cancer and other complications are addressed. H. pylori treatment is challenged by the continuously rising antibiotic resistance and demands for susceptibility testing with consideration of novel molecular technologies and careful selection of first line and rescue therapies. The role of H. pylori and antibiotic therapies and their impact on the gut microbiota are also considered.Progress made in the management of H. pylori infection is covered in the present sixth edition of the Maastricht/Florence 2021 Consensus Report, key aspects related to the clinical role of H. pylori infection were re-evaluated and updated. Forty-one experts from 29 countries representing a global community, examined the new data related to H. pylori infection in five working groups: (1) indications/associations, (2) diagnosis, (3) treatment, (4) prevention/gastric cancer and (5) H. pylori and the gut microbiota. The results of the individual working groups were presented for a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in various clinical fields.

The emergent phenomenon of aspirin resistance: insights from genetic association studies

Despite the clinical benefits of aspirin, the interindividual variation in response to this antiplatelet drug is considerable. The manifestation of aspirin resistance (AR) is frequently observed, although this complex process remains poorly understood. While AR etiology is likely to be multifactorial, genetic factors appear to be preponderant. According to several genetic association studies, both genome-wide and candidate gene studies, numerous SNPs in cyclooxygenase, thromboxane and platelet receptors-related genes have been identified as capable of negatively affecting aspirin action. Thus, it is essential to understand the clinical relevance of AR-related SNPs as potential predictive and prognostic biomarkers as they may be essential to defining the AR phenotype.

Does photobiomodulation therapy combined to static magnetic field (PBMT-sMF) promote ergogenic effects even when the exercised muscle group is not irradiated? A randomized, triple-blind, placebo-controlled trial

Background

The direct application of photobiomodulation therapy (PBMT) using low-level laser therapy (LLLT) and light emitting diodes (LEDs) combined with a static magnetic field (sMF) (PBMT-sMF) to target tissues is shown to improve muscle performance and recovery. Studies have reported possible PBMT effects when a local distant to the target tissue is irradiated. Notably, the extent of these effects on musculoskeletal performance and the optimal site of irradiation remain unclear, although this information is clinically important since these aspects could directly affect the magnitude of the effect. Therefore, we investigated the effects of local and non-local PBMT-sMF irradiations on musculoskeletal performance and post-exercise recovery before an eccentric exercise protocol.

Methods

This randomized, triple-blind (participants, therapists and assessors), placebo-controlled trial included 30 healthy male volunteers randomly assigned to the placebo, local, and non-local groups. Active or placebo PBMT-sMF was applied to 6 sites of the quadriceps muscle of both legs. An eccentric exercise protocol was used to induce fatigue. The primary outcome was peak torque assessed by maximal voluntary contraction (MVC). The secondary outcomes were delayed onset muscle soreness (DOMS) measured by visual analogue scale (VAS), muscle injury assessed by serum creatine kinase activity (CK), and blood lactate levels. Evaluations were performed before the eccentric exercise protocol (baseline), as well as immediately after and 1, 24, 48, and 72 h upon protocol completion.

Results

Ten volunteers were randomized per group and analysed for all outcomes. Compared to the placebo and non-local groups, irradiation with PBMT-SMF led to statistically significant improvement (p < 0.05) with regard to all variables in the local group. The outcomes observed in the non-local group were similar to those in the placebo group with regard to all variables.The volunteers did not report any adverse effects.

Conclusion

Our results support the current evidence that local irradiation of all exercised muscles promotes ergogenic effects. PBMT-sMF improved performance and reduced muscle fatigue only when applied locally to muscles involved in physical activity.

Trial registration

NCT03695458. Registered October 04th 2018.

POLYMORPHISM OF THE COX-2 GENE AND SUSCEPTIBILITY TO COLON AND RECTAL CANCER

Background:

The colorectal neoplasm is the fourth most common malignancy among males and the third among females. In the Western world is estimated that 5% of the population will develop it, making this disease a major public health problem.

Aim:

To analyze the prevalence of the polymorphism -765G / C region of the COX-2 gene in colorectal cancer patients compared to a control group, analyzing the possible association between this polymorphism and susceptibility to colorectal cancer.

Method:

This is a case-control study with 85 participants. Were selected 25 with colorectal cancer (case group) and 60 participants without colorectal neoplasia (control group). The molecular genetic analysis was perform to identify the polymorphism -765G / C COX2 gene with standard literature technique. In addition, patient’s clinical and pathological data were analyzed.

Results:

There was a light increase in prevalence between men in the case group, although this difference was not statistically significant. The results showed a high prevalence of GC and CC genotype in individuals with colorectal cancer, demonstrating an association between the presence of the polymorphism in the COX2 gene and susceptibility to colorectal cancer in this pattern (p=0.02). Similarly, there was also difference in allele frequencies in the groups. When patients with cancer were separated by tumor location, there was a higher prevalence of polymorphism in the left colon (p=0.02).

Conclusion:

The polymorphism in the COX2 gene is associated with increased susceptibility to colorectal cancer, specially rectosigmoid tumors.

Single nucleotide polymorphism rs4648298 in miRNAs hsa-miR21 and hsa-miR590 binding site of COX gene is a strong colorectal cancer determinant

Background

Genetic determinants are considered as driving forces in development colorectal cancer (CRC), a malignancy that ranks as the second cause of cancer death in the world. Single nucleotide polymorphisms (SNPs), are considered as the main genetic factor in cancers susceptibility. MicroRNAs are critical players in posttranslational gene regulation by binding to their specific recognition sequences located at 3' untranslated region (UTR) of mRNAs. In present study we have elucidated the role of 9,850 A > G (rs4648298), in development of sporadic CRC in Iranian population.

Methods

A case-control study using 88 CRC patients and 88 noncancerous counterparts was undertaken in order to determine rs4648298 genotypes using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Also, a meta-analysis was performed based on 9 articles accessed via the MEDLINE, Cochrane review, Google Scholar and Scopus databases.

Results

AA genotype was determined to be associated with significant decreased risk of CRC in our study population [odds ratio (OR) =0.14; 95% confidence interval (CI), 0.05-0.34; P<0.001]. In a meta-analysis on 6 risk estimates for the AG versus AA genotype, we found a significant inverse association between AG SNPs and risk of gastric adenocarcinoma, CRC, breast cancer and prostate cancer (OR =0.86; 95% CI, 0.76-0.98; P<0.02).

Conclusions

Our results suggest significant correlation between rs4648298 polymorphism and CRC risk in Iranian population.

Cyclooxygenase-2 gene polymorphisms and susceptibility to colorectal cancer in a Brazilian population

BACKGROUND

Multi-ethnicity of Brazilian population displays high levels of genomic diversity. Polymorphism may detect people at higher risk of developing cancer, distinctive response to treatment, and prognosis. Cyclooxygenase-2 (COX-2) is induced in response to growth factors and cytokines, and is expressed in inflammatory diseases, precancerous lesions and colorectal cancer (CRC). The aim of this study was to evaluate the influence of COX-2 -1195A > G and 8473T > C polymorphisms as a risk factor of developing CRC.

METHODS

We evaluated COX-2 Single Nucleotide Polymorphism (SNP) of 230 CRC patients and 196 healthy controls by Real-Time Polymerase Chain Reaction.

RESULTS

Populations were in Hardy-Weinberg equilibrium (HWE), except for control group of 8473T > C SNP. The frequencies were similar in both groups for genotypes and haplotypes. There was no association between studied polymorphisms and risk of CRC.

CONCLUSIONS

The gene polymorphisms studied do not participate in the genetic susceptibility to CRC in a Brazilian population.

Influence of Genetic Polymorphisms in Prostaglandin E2 Pathway (COX-2/HPGD/SLCO2A1/ABCC4) on the Risk for Colorectal Adenoma Development and Recurrence after Polypectomy

Objectives:

Deregulation of prostaglandin E₂ (PGE₂) levels reported in colorectal carcinogenesis contributes to key steps of cancer development. Our aim was to evaluate the influence of the genetic variability in COX-2/HPGD/SLCO2A1/ABCC4 PGE₂ pathway genes on the development and recurrence of colorectal adenomas.

Methods:

A case-control study was conducted gathering 480 unscreened individuals and 195 patients with personal history of adenomas. A total of 43 tagSNPs were characterized using the Sequenom platform or real-time PCR.

Results:

Ten tagSNPs were identified as susceptibility biomarkers for the development of adenomas. The top three most meaningful tagSNPs include the rs689466 in COX-2 (odds ratio (OR)=3.23; 95% confidence interval (CI): 1.52–6.86), rs6439448 in SLCO2A1 (OR=0.38; 95% CI: 0.22–0.65) and rs1751051 in ABCC4 genes (OR=2.75; 95% CI: 1.58–4.80). The best four-locus gene–gene interaction model included the rs1346271, rs1863642 and rs12500316 single nucleotide polymorphisms in HPGD and rs1678405 in ABCC4 genes and was associated with a 13-fold increased susceptibility (95% CI: 3.84–46.3, P<0.0001, cross-validation (CV) accuracy: 0.78 and CV consistency: 8/10). Interesting, in low-risk patients the ABCC4 rs9524821AA genotype was associated not only with a higher hazard ratio (HR=2.93; 95% CI: 1.07–8.03), but half of these patients had adenoma recurrence at 60 months, considerably higher than the 21% noticed in low-risk patients.

Conclusions:

Genetic polymorphisms in COX-2/PGE₂ pathway appear to contribute to the development of colorectal adenomas and influence the interval time to adenomas recurrence. The definition of risk models through the inclusion of genetic biomarkers might improve the adherence and optimization of current screening and surveillance guidelines for colorectal cancer prevention.

Associations between single nucleotide polymorphisms of COX-2 and MMP-2 genes and colorectal cancer susceptibility in the Saudi population

BACKGROUND

It has been reported that COX-2 expression is associated with MMP-2 expression in thyroid and breast cancers, suggesting that MMPs are linked to COX-2-mediated carcinogenesis. Several polymorphisms within the MMP2 promoter region have been reported in cases with oncogenesis and tumor progression, especially in colorectal carcinogenesis.

MATERIALS AND METHODS

This research evaluated risk of association of the SNPs, including genes for COX-2 (A/G transition at +202) and MMP-2 (C/T transition at-1306), with colorectal cancer in 125 patients and 125 healthy controls.

RESULTS AND CONCLUSIONS

Our data confirmed that MMP2 C-1306 T mutations were significantly more common in colon cancer patients than in our control Saudi population; p=0.0121. On the other hand in our study, there was no significant association between genotype distribution of the COX2 polymorphism and colorectal cancer; p=0.847. An elevated frequency of the mutated genotype in the control group as compared to the patients subjects indeed suggested that this polymorphism could decrease risk in the Saudi population. Our study confirmed that the polymorphisms that could affect the expressions of MMP-2 and COX-2 the colon cancer patients were significantly higher than that in the COX-2 negative group. The frequency of individuals with MMP2 polymorphisms in colon cancer patients was higher than individuals with combination of COX2 and MMP2 polymorphisms. Our study confirmed that individuals who carried the polymorphisms that could affect the expressions of COX2 are more susceptible to colon cancer. MMP2 regulatory polymorphisms could be considered as protective; further studies need to confirm the results with more samples and healthy subjects.

The prostaglandin synthase 2/cyclooxygenase 2 (PTGS2/ COX2) rs5277 polymorphism does not influence risk of colorectal cancer in an Iranian population

BACKGROUND

The prostaglandin-endoperoxide synthase 2 [PTGS2, commonly known as cyclooxygenase-2 (COX-2)] is an enzyme induced by proinflammatory stimuli that is often overexpressed in malignant tissue and involved in the synthesis of prostaglandins and thromboxanes, regulators of processes such as inflammation, cell proliferation, and angiogenesis, all relevant for cancer development. We investigated whether a functional genetic polymorphism, rs5277, in COX-2 may have a risk-modifying effect on sporadic colorectal cancer in an Iranian population.

MATERIALS AND METHODS

We conducted a case-control study on 167 patients with colorectal cancer and 197 cancer-free controls in Taleghani Hospital in Tehran, Iran, between 2007 and 2011. Peripheral blood samples of both groups were processed for DNA extraction and genotyping of the COX-2 gene polymorphism (rs5277) using PCR-RFLP. RFLP results were confirmed by direct sequencing. Logistic regression analysis was performed to calculate the adjusted odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS

There was no significant difference in the distribution of COX-2 gene rs5277 polymorphism genotype and the allelic form, among CRC patients compared with the healthy control group (p: 0.867).

CONCLUSIONS

Our results suggest that rs5277 polymorphism in COX2 could not be a good prognostic indicator for patients with CRC.

Lack of association between COX-2 8473T>C polymorphism and breast cancer risk: a meta-analysis

Aim of the study

Results of recent published studies on the association between the COX-2 8473T>C polymorphism and the risk of breast cancer have often been conflicting. To make a more precise estimation of the potential relationship, a meta-analysis was performed.

Material and methods

A total of seven case-control studies with 7,033 cases and 9,350 controls were included in the current meta-analysis through searching the databases of PubMed, Embase, and Cochrane Library (up to March 1^st, 2013). The odds ratio (OR) and 95% confidence interval (95% CI) were calculated to assess the strength of the association. The meta-analysis was conducted in a fixed/random effect model.

Results

We found no significant associations for all genetic models after all studies were pooled into the meta-analysis (for C vs. T: OR = 0.974, 95% CI: 0.906–1.047, p = 0.471; for CC vs. TT: OR = 0.957, 95% CI: 0.803–1.140, p = 0.62; for TC vs. TT: OR = 0.964, 95% CI: 0.881–1.055, p = 0.421; for CC + TC vs. TT: OR = 0.963, 95% CI: 0.880–1.053, p = 0.406; for CC vs. TT + TC: OR = 0.978, 95% CI: 0.831–1.15, p = 0.788). We also observed no obvious associations in the subgroup analyses by ethnicity (Caucasian) and source of controls (population based, PB) for all genetic models.

Conclusions

Current evidence suggests that the COX-2 8473T>C polymorphism is not associated with breast cancer risk.

COX-1 (PTGS1) and COX-2 (PTGS2) polymorphisms, NSAID interactions, and risk of colon and rectal cancers in two independent populations

PURPOSE

Nonsteroidal anti-inflammatory drugs (NSAIDs) target the prostaglandin H synthase enzymes, cyclooxygenase (COX)-1 and COX-2, and reduce colorectal cancer risk. Genetic variation in the genes encoding these enzymes may be associated with changes in colon and rectal cancer risk and in NSAID efficacy.

METHODS

We genotyped candidate polymorphisms and tag SNPs in PTGS1 (COX-1) and PTGS2 (COX-2) in a population-based case–control study (Diet, Activity and Lifestyle Study, DALS) of colon cancer (n = 1,470 cases/1,837 controls) and rectal cancer (n = 583/775), and independently among cases and controls from the Colon Cancer Family Registry (CCFR; colon n = 959/1,535, rectal n = 505/839).

RESULTS

In PTGS2, a functional polymorphism (-765G[C; rs20417) was associated with a twofold increased rectal cancer risk (p = 0.05) in the DALS. This association replicated with a significant nearly fivefold increased risk of rectal cancer in the CCFR study (ORCC vs. GG = 4.88; 95 % CI 1.54–15.45; ORGC vs. GG = 1.36; 95 %CI 0.95–1.94). Genotype–NSAID interactions were observed in the DALS for PTGS1 and rectal cancer risk and for PTGS2 and colon cancer risk, but were no longer significant after correcting for multiple comparisons and did not replicate in the CCFR. No significant associations between PTGS1 polymorphisms and colon or rectal cancer risk were observed.

Genetic variability in key genes in prostaglandin E2 pathway (COX-2, HPGD, ABCC4 and SLCO2A1) and their involvement in colorectal cancer development

The pro-carcinogenic effects of prostaglandin E2 (PGE₂) in colonic mucosa are not only regulated by the rates between Cyclooxygenase-2 (COX-2) biosynthesis and 15-Hydroxyprostaglandin Dehydrogenase (15-PGDH)-dependent degradation but also the steady-state levels of PGE₂ in extracellular microenvironment, maintained by key specific prostaglandin transporters, the Multidrug Resistance Protein (MRP4) (efflux carrier) and Prostaglandin Transporter (PGT) (influx carrier). To understand the contribution of genetic variability in genes coding for COX-2/15-PGDH/MRP4/PGT proteins in CRC development, we conducted a hospital-based case-control study involving 246 CRC patients and 480 cancer-free controls. A total of 51 tagSNPs were characterized using the Sequenom platform through multiplexed amplification followed by mass-spectrometric product separation or allelic discrimination using real-time PCR. Seven tagSNPs were implicated in CRC development: the rs689466 in COX-2 gene, the rs1346271 and rs1426945 in 15-PGDH, the rs6439448 and rs7616492 in PGT and rs1751051 and rs1751031 in MRP4 coding genes. Upon a stratified analysis a measurable gene-environment interaction was noticed between rs689466 and smoking habits, with individuals ever-smokers carriers of rs689466 GG homozygous genotype having a nearly 6-fold increased susceptibility for CRC onset (95%CI: 1.49–22.42, P = 0.011). Furthermore, the multifactor dimensionality reduction (MDR) analysis identified an overall four-factor best gene-gene interactive model, including the rs1426945, rs6439448, rs1751051 and rs1751031 polymorphisms. This model had the highest cross-validation consistency (10/10, P<0.0001) and an accuracy of 0.6957 and was further associated with a 5-fold increased risk for CRC development (95%CI: 3.89–7.02, P<0.0001). In conclusion, specific low penetrance genes in the pro-carcinogenic PGE₂ pathway appear to modulate the genetic susceptibility for CRC development. A clearer understanding on CRC etiology through the identification of biomarkers of colorectal carcinogenesis might allow a better definition of risk models that are more likely to benefit from targeted preventive strategies to reduce CRC burden.

Impact of COX2 genotype, ER status and body constitution on risk of early events in different treatment groups of breast cancer patients

The COX2 rs5277 (306G>C) polymorphism has been associated with inflammation-associated cancers. In breast cancer, tumor COX-2 expression has been associated with increased estrogen levels in estrogen receptor (ER)-positive and activated Akt-pathway in ER-negative tumors. Our study investigated the impact of COX2 genotypes on early breast cancer events and treatment response in relation to tumor ER status and body constitution. In Sweden, between 2002 and 2008, 634 primary breast cancer patients, aged 25–99 years, were included. Disease-free survival was assessed for 570 rs5277-genotyped patients. Body measurements and questionnaires were obtained preoperatively. Clinical data, patient- and tumor-characteristics were obtained from questionnaires, patients' charts, population registries and pathology reports. Minor allele(C) frequency was 16.1%. Genotype was not linked to COX-2 tumor expression. Median follow-up was 5.1 years. G/G genotype was not associated with early events in patients with ER-positive tumors, adjusted HR 0.77 (0.46–1.29), but conferred an over 4-fold increased risk in patients with ER-negative tumors, adjusted HR 4.41 (1.21–16.02)(p_interaction = 0.015). Chemotherapy-treated G/G-carriers with a breast volume ≥850 ml had an increased risk of early events irrespective of ER status, adjusted HR 8.99 (1.14–70.89). Endocrine-treated C-allele carriers with ER-positive tumors and a breast volume ≥850 ml had increased risk of early events, adjusted HR 2.30 (1.12–4.75). COX2 genotype, body constitution and ER status had a combined effect on the risk of early events and treatment response. The high risk for early events in certain subgroups of patients suggests that COX2 genotype in combination with body measurements may identify patients in need of more personalized treatment.

The role of inflammation in gastric cancer

Gastric cancer, despite its declining incidence rate, is still the second cause of cancer-related death worldwide, killing 750,000 people each year and remaining the second common type of cancer. The best examples of inflammation-associated cancer in human beings may be gastric cancer. Understanding the molecular mechanism of the inflammation in gastric carcinogenesis is important for developing new strategies against gastric cancer.

COX-2-765G>C polymorphism increases the risk of cancer: a meta-analysis

Background

Chronic inflammation has been regarded as an important mechanism in carcinogenesis. Inflammation-associated genetic variants have been highly associated with cancer risk. Polymorphisms in the gene cyclooxygenase-2 (COX-2), a pro-inflammation factor, have been suggested to alter the risk of multiple tumors, but the findings of various studies are not consistent.

Methods

A literature search through February 2013 was performed using PubMed, EMBASE, and CNKI databases. We used odds ratios (ORs) with confidence intervals (CIs) of 95% to assess the strength of the association between the COX-2-765G>C polymorphism and cancer risk in a random-effect model. We also assessed heterogeneity and publication bias.

Results

In total, 65 articles with 29,487 cancer cases and 39,212 non-cancer controls were included in this meta-analysis. The pooled OR (95% CIs) in the co-dominant model (GC vs. GG) was 1.11 (1.02–1.22), and in the dominant model ((CC+GC) vs. GG), the pooled OR was 1.12 (1.02–1.23). In the subgroup analysis, stratified by cancer type and race, significant associations were found between the-765 C allele and higher risk for gastric cancer, leukemia, pancreatic cancer, and cancer in the Asian population.

Conclusion

In summary, the COX-2-765 C allele was related to increased cancer susceptibility, especially gastric cancer and cancer in the Asian population.

Cyclooxygenase-2 polymorphisms were associated with the risk of gastric cancer: evidence from a meta-analysis based on case-control studies

The associations between cyclooxygenase-2 (COX-2) polymorphisms (-765G>C, -1195G>A, and -587G>A) and risk of gastric cancer have been investigated, but the results were inconsistent. The aim of this study was to explore the associations between COX-2 polymorphisms and risk of gastric cancer using a meta-analytic method. We searched the databases of PubMed, Embase, and Wanfang (Chinese database) to identify the eligible studies. Odds ratio and 95 % confidence interval (OR and 95% CI) were used as effect size, and combined analyses were conducted using fixed- or random-effects model. Overall, ten studies for COX-2-765G>C, six studies for -1195G>A, and three studies for -587G>A were included in this study. The results for combined analysis for COX-2-765G>C indicated that C allele was significantly associated with increased risk of gastric cancer compared with G allele, especially for Asians (OR and 95 % CI: 1.58 (1.06-2.35), P(z-test) = 0.03, and P heterogeneity <0.01 for CC+GC vs. GG). In addition, the A allele of COX-2-1195G>A was also significantly associated with risk of gastric cancer compared with G allele (OR and 95 % CI: 1.20 (1.09-1.32), P(z-test) <0.001, and P(heterogeneity) = 0.82 for A carriers vs. G carriers). In contrast, the COX-2-587G>A polymorphism was not associated with risks of gastric cancer. In summary, this meta-analysis indicated that the COX-2-765G>C and -1195G>A polymorphisms were significantly associated with risk of gastric cancer development.

The -1195G allele increases the transcriptional activity of cyclooxygenase-2 gene (COX-2) in colon cancer cell lines

Up-regulation of cyclooxygenase-2 (COX-2) is an early and key event in human colorectal carcinogenesis (CRC). Nevertheless, the molecular mechanisms leading to this over-expression are largely unknown. We previously reported an association between the -1195G allele and higher predisposition for CRC in a Caucasian population. The biological explanation for the involvement of this polymorphism in CRC remains elusive. We aimed to functionally characterize the influence of the -1195A>G promoter region polymorphism on COX-2 transcription activity in colon cancer cell lines. Luciferase reporter assays were performed to assess whether the -1195A/G alleles influenced COX-2 transcription. The COX-2 promoter's region containing either the -1195A or -1195G alleles was cloned into pGL3-basic reporter vector. The reporter vectors were transiently co-transfected with the pGL4.73 control plasmid to HCT-116 and HCA-7 colon cancer cell lines. The levels of reporter gene expression driven by the -1195G allele-containing COX-2 promoter were significantly higher in both colon cancer cell lines. A 2.2-fold increase in promoter activity was observed in the HCT-116 cell line (P < 0.001), and this over-expression was even more noticeable in the HCA-7 COX-2 expressing cell line with a threefold higher transcriptional activity (P = 0.001). The -1195G allele appeared to enhance COX-2 transcription, providing a molecular basis underlying the increased susceptibility for CRC and potentially a new mechanism for COX-2 overexpression.

Functional polymorphisms of Toll-like receptors 2 and 4 alter the risk for colorectal carcinoma in Europeans

BACKGROUND

Colon carcinogenesis is associated with increased expression levels of Toll-like receptor 2 and Toll-like receptor 4.

AIM

To determine in a Caucasian population the role of Toll-like receptor 2 and Toll-like receptor 4 polymorphisms in colorectal cancer development.

METHODS

Hospital based multicentre case control study involving 193 colorectal cancer patients and 278 healthy individuals. DNA samples were extracted from blood cells and genotyping of TLR2+597T>C, TLR2-4760T>C, TLR4-3745A>G, TLR2Arg753Gln, TLR4Asp299Gly was performed. Functionality of risk polymorphisms was evaluated through production of TNF-α in cell culture and Toll-like receptors levels quantified by real-time RT-PCR.

RESULTS

TLR2+597CC homozygous had 5-fold decreased risk (odds ratio (OR)=0.21, 95% CI: 0.09-0.50, p<0.001) and TLR4 299Gly homozygous 3-fold increased risk of colorectal cancer (OR=3.30, 95% CI: 1.18-9.28, p=0.015). In stratified analysis, TLR2+597CC genotype protective effect was even higher in overweight individuals (OR=0.17, 95% CI: 0.06-0.53, p<0.001) and in never smokers (OR=0.11, 95% CI: 0.02-0.51, p=0.001). Also, the increased risk effect for TLR4 299Gly homozygous genotype was higher in overweight individuals (OR=8.67, 95% CI: 1.11-87.85, p=0.011). TLR2+597T>C polymorphism conferred 41% less (p=0.03) and TLR4Asp299Gly 65% more TNF-α production (p=0.02) with no differences in Toll-like receptors levels.

CONCLUSION

Functional Toll-like receptor 2 and Toll-like receptor 4 polymorphisms significantly alter the risk to have colorectal cancer. Obesity and smoking may influence the risk for colorectal cancer in individuals presenting these genetic profiles.

Prognostic role of host cyclooxygenase and cytokine genotypes in a Caucasian cohort of patients with gastric adenocarcinoma

Background

Genetic factors influencing the prognosis of gastric adenocarcinoma (GAC) are not well known. Given the relevance of cytokines and other pro-inflammatory mediators in cancer progression and invasiveness, we aimed to assess the prognostic role of several functional cytokine and cyclooxygenase gene polymorphisms in patients with GAC.

Methodology

Genomic DNA from 380 Spanish Caucasian patients with primary GAC was genotyped for 23 polymorphisms in pro-inflammatory (IL1B, TNFA, LTA, IL6, IL12p40), anti-inflammatory (IL4, IL1RN, IL10, TGFB1) cytokine, and cyclooxygenase (PTGS1 and PTGS2) genes by PCR, RFLP and TaqMan assays. Clinical and histological information was collected prospectively. Survival curves were estimated by the Kaplan-Meier method and compared using the log rank test. Outcome was determined by analysis of Cox proportional hazards, adjusting for confounding factors.

Results

The median follow-up period and median overall survival (OS) time were 9.9 months (range 0.4–120.3) and 10.9 months (95% CI: 8.9–14.1), respectively. Multivariate analysis identified tumor stages III (HR, 3.23; 95% CI:2–5.22) and IV (HR, 5.5; 95% CI: 3.51–8.63) as independent factors associated with a significantly reduced OS, whereas surgical treatment (HR: 0.44; 95%CI: 0.3–0.6) was related to a better prognosis of the disease. Concerning genetic factors, none of the 23 polymorphisms evaluated in the current study did influence survival. Moreover, no gene-environment interactions on GAC prognosis were observed.

Conclusions

Our results show that, in our population, the panel of selected pro- and anti-inflammatory cytokine, and cyclooxygenase gene polymorphisms are not relevant in determining the prognosis of gastric adenocarcinoma.

The COX-2-1195AA Genotype Is Associated with Diffuse-Type Gastric Cancer in Korea

BACKGROUND/AIMS

The potential role of the cyclooxygenase (COX)-2 polymorphism has been reported in relation to the risk of gastrointestinal tract malignancies. Therefore, we investigated whether COX-2 polymorphisms are associated with the risk of gastric cancer (GC) in Korea, one of the areas with a high prevalence of this condition.

METHODS

We evaluated the genotypic frequencies of COX-2-765 and -1195 in 100 peptic ulcer patients, 100 GC patients, and 100 healthy controls. The polymorphisms of the COX-2-765 and -1195 genes were analyzed by polymerase chain reaction and restriction fragment length polymorphisms.

RESULTS

The frequencies of the COX-2-1195 GG, GA, and AA genotype were 20%, 60%, and 20% in intestinal-type GC and 8%, 48%, and 44% in diffuse-type GC, respectively (p=0.021). There were no significant differences in the frequency of COX-2-765 genotypes between intestinal-type GC and diffuse-type GC (p=0.603). Age- and sex-adjusted logistic regression analysis showed that the COX-2-1195 AA genotype was the independent risk factor of diffuse-type GC compared with the COX-2-1195 GG genotype (p=0.041; odds ratio, 6.22; 95% confidence interval, 1.077 to 35.870).

CONCLUSIONS

The COX-2-1195 AA genotype may render subjects more susceptible to diffuse-type GC.

[Low penetrance gene polymorphisms involved in Helicobacter pylori-immune response. Relevance on gastric cancer risk]

Gastric cancer is a complex pathology which represents a worldwide health burden due to its high prevalence and poor prognosis. Therefore, prevention and early detection are considered the best options for controlling the disease. Current research is based on the study of genetic variants that confer a higher risk and their interactions with environmental exposure. A deeper knowledge of factors involved on gastric cancer development may allow identification of those individuals at elevated risk and will provide useful predictive information for subgroups of patients who need surveillance or early treatment strategies. In the present paper we review in a comprehensive manner, the most recent published studies on the contribution of gene polymorphisms and Helicobacter pylori infection to gastric cancer risk.

The ketogenic diet for the treatment of glioma: insights from genetic profiling

Seizures, particularly first onset seizures in adults, are a diagnostic hallmark of brain tumors (Giglio and Villano, 2010). Unfortunately, malignant brain tumors are almost uniformly fatal due, in part, to the limitations of available therapies. Improvement in the survival of brain cancer patients requires the design of new therapeutic modalities including those that enhance currently available therapies. One potential strategy is to exploit differences in metabolic regulation between normal cells and tumor cells through dietary approaches. Previous studies have shown that a high-fat, low-carbohydrate ketogenic diet (KD) extends survival in animal models of glioma; however, the mechanism for this effect is not entirely known. We examined the effects of an experimental KD on a mouse model of glioma, and compared patterns of gene expression in tumors versus contralateral non-tumor containing brain from animals fed either a KD or a standard diet. We found that the KD reduced reactive oxygen species (ROS) production in tumor cells. Gene expression profiling demonstrated that the KD induces an overall reversion to expression patterns seen in non-tumor specimens, and a number of genes involved in modulating ROS levels and oxidative stress were altered in tumor cells. In addition, there was reduced expression of genes involved in signal transduction from growth factors known to be involved in glioma growth. These results suggest that the anti-tumor effect of the KD is multifactorial, and elucidation of genes whose expression is altered will help identify mechanisms through which ketones inhibit tumor growth, reduce seizure activity and provide neuroprotection.

A new cyclo-oxygenase-2 gene variant in the Han Chinese population is associated with an increased risk of gastric carcinoma

BACKGROUND AND OBJECTIVE

Cyclo-oxygenase-2 (COX-2, also known as prostaglandin synthase 2) influences carcinogenesis through regulation of angiogenesis, apoptosis, and cytokine expression. COX-2 is encoded by the gene PTGS2. Several studies have suggested that PTGS2 single-nucleotide polymorphisms (SNPs) are involved in gastrointestinal carcinogenesis. In this study, we observed the PTGS2 Val511Ala (5939T/C) polymorphism in the Chinese population for the first time, and investigated whether this polymorphism might contribute to gastric cancer in a case-control study conducted in the Gansu province of China, a high-risk area for gastric cancer.

METHODS

We determined the genotypes of 110 gastric cancer patients and 138 controls using polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) analysis. Data were statistically analyzed using a chi-squared test and a logistic regression model.

RESULTS AND CONCLUSION

In our analysis, PTGS2 5939C allele carriers were at increased risk of gastric cancer (odds ratio [OR] 1.742; 95% confidence interval [CI] 1.009, 3.005; p = 0.045). We also found an interaction between Helicobacter pylori infection, a family history of gastric cancer, and presence of the 5939C allele. This study further indicated that H. pylori-positive status and family history jointly contribute to a higher risk of gastric cancer.

CD36 protein is involved in store-operated calcium flux, phospholipase A2 activation, and production of prostaglandin E2

The scavenger receptor FAT/CD36 contributes to the inflammation associated with diabetes, atherosclerosis, thrombosis, and Alzheimer disease. Underlying mechanisms include CD36 promotion of oxidative stress and its signaling to stress kinases. Here we document an additional mechanism for the role of CD36 in inflammation. CD36 regulates membrane calcium influx in response to endoplasmic reticulum (ER) stress, release of arachidonic acid (AA) from cellular membranes by cytoplasmic phospholipase A(2)α (cPLA(2)α) and contributes to the generation of proinflammatory eicosanoids. CHO cells stably expressing human CD36 released severalfold more AA and prostaglandin E(2) (PGE(2)), a major product of AA metabolism by cyclooxygenases, in response to thapsigargin-induced ER stress as compared with control cells. Calcium influx after ER calcium release resulted in phosphorylation of cPLA(2) and its translocation to membranes in a CD36-dependent manner. Peritoneal macrophages from CD36(-/-) mice exhibited diminished calcium transients and reduced AA release after thapsigargin or UTP treatment with decreased ERK1/2 and cPLA(2) phosphorylation. However, PGE(2) production was unexpectedly enhanced in CD36(-/-) macrophages, which probably resulted from a large induction of cyclooxygenase 2 mRNA and protein. The data demonstrate participation of CD36 in membrane calcium influx in response to ER stress or purinergic receptor stimulation resulting in AA liberation for PGE(2) formation. Collectively, these results identify a mechanism contributing to the pleiotropic proinflammatory effects of CD36 and suggest that its targeted inhibition may reduce the acute inflammatory response.

Epstein-Barr virus-specific methylation of human genes in gastric cancer cells

Background

Epstein-Barr Virus (EBV) is found in 10% of all gastric adenocarcinomas but its role in tumor development and maintenance remains unclear. The objective of this study was to examine EBV-mediated dysregulation of cellular factors implicated in gastric carcinogenesis.

Methods

Gene expression patterns were examined in EBV-negative and EBV-positive AGS gastric epithelial cells using a low density microarray, reverse transcription PCR, histochemical stains, and methylation-specific DNA sequencing. Expression of PTGS2 (COX2) was measured in AGS cells and in primary gastric adenocarcinoma tissues.

Results

In array studies, nearly half of the 96 human genes tested, representing 15 different cancer-related signal transduction pathways, were dysregulated after EBV infection. Reverse transcription PCR confirmed significant impact on factors having diverse functions such as cell cycle regulation (IGFBP3, CDKN2A, CCND1, HSP70, ID2, ID4), DNA repair (BRCA1, TFF1), cell adhesion (ICAM1), inflammation (COX2), and angiogenesis (HIF1A). Demethylation using 5-aza-2'-deoxycytidine reversed the EBV-mediated dysregulation for all 11 genes listed here. For some promoter sequences, CpG island methylation and demethylation occurred in an EBV-specific pattern as shown by bisulfite DNA sequencing. Immunohistochemistry was less sensitive than was western blot for detecting downregulation of COX2 upon EBV infection. Virus-related dysregulation of COX2 levels in vitro was not recapitulated in vivo among naturally infected gastric cancer tissues.

Conclusions

EBV alters human gene expression in ways that could contribute to the unique pathobiology of virus-associated cancer. Furthermore, the frequency and reversability of methylation-related transcriptional alterations suggest that demethylating agents have therapeutic potential for managing EBV-related carcinoma.

Cyclooxygenase-2 polymorphisms and susceptibility to gastric carcinoma: A meta-analysis

AIM: To investigate the association of the cyclooxygenases-2 (COX-2) polymorphisms and susceptibility to gastric cancer (GC) by means of meta-analysis.

METHODS: Publications addressing the association between polymorphisms of COX-2 and susceptibility to GC were selected from the MEDLINE, EMBASE and CBMdisc databases. Data was extracted from the studies by 2 independent reviewers. The meta-analyses were performed by RevMan 5.0.23. From these data, odds ratio (OR) with 95% confidence interval (CI) was calculated.

RESULTS: Ten studies were retrieved reporting a total of 11 COX-2 polymorphisms. Carriers of -765C, -1195A, -1290G, *2430T alleles and *429TT genotype revealed increased risk for GC (OR = 1.71, 95% CI: 1.01-2.90, P = 0.05; OR = 1.58, 95% CI: 1.05-2.38, P = 0.03; OR = 1.55, 95% CI: 1.01-2.39, P = 0.05; OR = 2.62, 95% CI: 1.20-5.73, P = 0.02 and OR = 0.74, 95% CI: 0.59-0.95, P = 0.02, respectively).

CONCLUSION: The -765C, -1195A, -1290G, *2430T alleles and *429TT genotype of COX-2 polymorphisms were determined a significant association with susceptibility to GC.

Tumor-associated Macrophages (TAM) and Inflammation in Colorectal Cancer

Experimental and epidemiological studies indicate a strong link between chronic inflammation and tumor progression. Human colorectal cancer (CRC), a major cause of cancer-related death in Western countries, represents a paradigm for this link. Key features of cancer-related inflammation in CRC are the activation of transcription factors (e.g. NF-κB, STAT3), the expression of inflammatory cytokines and chemokines (e.g. TNFα, IL-6, CCL2, CXCL8) as well as a prominent leukocyte infiltrate. While considerable evidence indicates that the presence of lymphocytes of adaptive immunity may positively influence patient survival and clinical outcome in CRC, the role of tumor-associated macrophages (TAM) and of other lymphoid populations (e.g. Th17, Treg) is still unclear. In this review we will summarize the different and controversial effects that TAM play in CRC-related inflammation and progression of disease. The characterization of the most relevant inflammatory pathways in CRC is instrumental for the identification of new target molecules that could lead to improved diagnosis and treatment.

COX-2 polymorphisms and colorectal cancer risk: a strategy for chemoprevention

OBJECTIVE

COX-2, the inducible isoenzyme, was found to be overexpressed in approximately 85% of colorectal adenocarcinomas, contributing to key steps in tumor development. COX-2 polymorphisms that might modify the levels of protein expression would be anticipated to have a substantial influence on disease phenotype. Therefore, we sought to understand the role of three COX-2 polymorphisms (-1195A>G, -765G>C, and 8473T>C) in colorectal cancer (CRC) onset.

MATERIAL AND METHODS

We conducted a hospital-based case-control study involving 117 consecutively enrolled CRC patients and 256 healthy individuals without any clinical evidence of cancer. The COX-2 polymorphisms' genotypes were characterized by PCR-restriction fragment length polymorphism or real-time PCR techniques.

RESULTS

The -1195A>G polymorphism was associated with a 1.73-fold increased predisposition to CRC onset. In a stratified analysis, men and ever-smokers carrying -1195G allele (AG+GG) had an increased risk for CRC development (odds ratio: 2.58; 95% confidence intraval: 1.29-5.15 and odds ratio: 10.3; 95% confidence intraval: 3.37-31.2, respectively). More interestingly, men ever-smokers carrying -1195G allele appeared to have a nine-fold increased risk for CRC onset (95% CI: 2.94-27.6). No difference in the genotype's distribution was noticed between cases and controls for the remaining two polymorphisms.

CONCLUSION

The -1195A>G COX-2 polymorphism seems to modulate the genetic susceptibility for CRC onset, especially in men ever-smokers. This genetically based higher-risk group definition may help shift the balance between risk and benefits for the use of COX-2 inhibitors in chemoprevention that is currently hampered by the adverse gastrointestinal and cardiovascular side-effects.

Cyclooxygenase-2 polymorphisms, aspirin treatment, and risk for colorectal adenoma recurrence--data from a randomized clinical trial

Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step in the production of prostaglandins, potent mediators of inflammation. Chronic inflammation plays an important role in the development and progression of colorectal cancer. Aspirin inhibits COX-2 activity and lowers the risk for colorectal adenomas and cancer. We investigated whether common genetic variation in COX-2 influenced risk for colorectal adenoma recurrence among 979 participants in the Aspirin/Folate Polyp Prevention Study who were randomly assigned to placebo or aspirin and followed for 3 years for the occurrence of new adenomas. Of these participants, 44.2% developed at least one new adenoma during follow-up. Adjusted relative risks and 95% confidence intervals (95% CI) were calculated to test the association between genetic variation at six COX-2 single-nucleotide polymorphisms and adenoma occurrence and interaction with aspirin treatment. Two single-nucleotide polymorphisms were significantly associated with increased adenoma recurrence: for rs5277, homozygous carriers of the minor C allele had a 51% increased risk compared with GG homozygotes (relative risk, 1.51; 95% CI, 1.01-2.25), and for rs4648310, heterozygous carriers of the minor G allele had a 37% increased risk compared with AA homozygotes (relative risk, 1.37; 95% CI, 1.05-1.79). (There were no minor allele homozygotes.) In stratified analyses, there was suggestive evidence that rs4648319 modified the effect of aspirin. These results support the hypothesis that COX-2 plays a role in the etiology of colon cancer and may be a target for aspirin chemoprevention and warrant further investigation in other colorectal adenoma and cancer populations.

Cellular and molecular pathways linking inflammation and cancer

Several experimental and epidemiological evidence indicate that, irrespective of the trigger for the development (chronic infection/inflammation or genetic alteration), a "smouldering" inflammation is associated with the most of, if not all, tumours and supports their progression. Several evidence have highlighted that tumours promote a constant influx of myelomonocytic cells that express inflammatory mediators supporting pro-tumoral functions. Myelomonocytic cells are key orchestrators of cancer-related inflammation associated with proliferation and survival of malignant cells, subversion of adaptive immune response, angiogenesis, stroma remodelling and metastasis formation. Although the connection between inflammation and cancer is unequivocal the mechanistic basis of such association are largely unknown. Recent advances in the understanding of the cellular and molecular pathways involved in cancer-related inflammation as well as their potential relevance as diagnostic, prognostic and therapeutic targets are herein discussed.

Genetic aspects of inflammation

Chronic inflammation underlies many human diseases including cancer. The magnitude and direction of the inflammatory response is often directed by host genetic factors interacting with environmental exposures. Quite often, the environmental trigger is a microbial agent and the host's genetically determined response is crucial in setting the right tone for handling this threat. An inadequate response runs the risk of allowing the infection to become permanently established causing chronic damage, while too vigorous a response might cause collateral damage to the host's essential physiological pathways. Helicobacter pylori-induced gastric cancer is a paradigm for microbially induced and chronic inflammation-driven malignancy. In this review, we summarise current knowledge about the role of host genetic factors in the pathogenesis of this malignancy. The review illustrates the basic principles of genetic epidemiology and host-bacterial interactions and offers an example of how basic knowledge of the pathophysiology of a disease directed the search for the relevant host genetic factors. This contrasts with current approaches, driven by advanced technology, where genetic risk factors are being identified first with the hope that these will shed light on the pathogenesis of disease. Both approaches are necessary to make advances in reducing disease burden in society.