Interactions between environmental factors and polymorphisms in angiogenesis pathway genes in esophageal adenocarcinoma risk: a case-only study

hOGG1: A novel mediator in nitrosamine-induced esophageal tumorigenesis

BACKGROUND

The effect of human 8-Oxoguanine DNA Glycosylase (hOGG1) on exogenous chemicals in esophageal squamous cell carcinoma (ESCC) remain unclear. The study plans to determine hOGG1 expression levels in ESCC and possible interactions with known environmental risk factors in ESCC.

MATERIAL AND METHODS

We analyzed levels of exposure to urinary nitrosamines in volunteers from high and low prevalence areas by GC-MS. And we performed the interaction between hOGG1 gene and nitrosamine disinfection by-products by analyzing hOGG1 gene expression in esophageal tissues.

RESULTS

In ESCC, nitrosamine levels were significantly increased and hOGG1 mRNA expression levels were significantly decreased. There was a statistically significant interaction between reduced hOGG1 mRNA levels and non-tap drinking water sources in ESCC. The apparent indirect association between ESCC and NMEA indicated that 33.4% of the association between ESCC and NMEA was mediated by hOGG1.

CONCLUSION

In populations which exposed to high levels of environmental pollutants NDMA, low expression of hOGG1 may promote the high incidence of esophageal cancer in Huai'an. hOGG1 may be a novel mediator in nitrosamine-induced esophageal tumorigenesis.

Hypoxia-induced tumor exosomes promote angiogenesis through miR-1825/TSC2/mTOR axis in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is characterized by enhanced angiogenesis resulting in poor prognosis despite improvements in diagnostic/therapeutic techniques. Here, we aimed at investigating potential roles of miR-1825 enclosed in OSCC-derived exosomes on angiogenesis under hypoxic conditions.

METHODS

Effects of miR-1825 mimic/inhibitor as well as hypoxia-induced tumor derived exosomes on human umbilical vein endothelial cells (HUVECs) were evaluated using cell viability, migration/invasion, tube formation, and spheroid-based 3D angiogenesis assays.

RESULTS

Hypoxic conditions caused significant increase in miR-1825 levels in OSCC cells and hiTDEs. miR-1825 alone and within hiTDEs promoted endothelial cell viability, migration, invasion, and angiogenic potential, which is reversed via inhibition of miR-1825 expression. miR-1825 within hiTDEs altered the angiogenesis potential of HUVEC cells via deregulation of TSC2/mTOR axis.

CONCLUSIONS

We showed that hypoxia led to OSCC-derived exosome mediated transfer of miR-1825 to HUVECs and enhanced angiogenesis in OSCC in vitro.

Prediagnostic adult body mass index change and esophageal adenocarcinoma survival

Background

We examined whether body mass index (BMI) changes in adulthood, prior to disease onset, are associated with overall survival among esophageal adenocarcinoma patients.

Methods

We included 285 histologically confirmed patients with a complete baseline BMI questionnaire. Using extended Cox regression models, we obtained adjusted hazard ratios (HRs) for the associations between overall survival and BMI at diagnosis, BMI 6 months before diagnosis, self‐reported average adult BMI, and ΔBMI (BMI 6 months before diagnosis minus average adult BMI), categorized into tertiles <0 kg/m² (BMI loss), ≥0 and <1.25 kg/m² (stable BMI), and ≥1.25 kg/m² (BMI gain). We also assessed interaction between ΔBMI and average adult BMI (≥ kg/m² versus <27.5 kg/m²) with overall survival.

Results

Body mass index at diagnosis >25 and <35 kg/m² was associated with better overall survival. Compared to patients with stable BMI in adulthood, patients who gained BMI throughout adulthood had 1.68 times the all‐cause hazard of death (95% CI: 1.17‐2.43; P < .01), independent of diagnosis BMI and percent weight loss 6 months before diagnosis. Compared to patients with average adult BMI < 27.5 who maintained stable adult BMI, patients with average adult BMI ≥ 27.5 kg/m² who gained BMI had the worst survival (HR = 3.05; 95% CI 1.62‐5.72; P < .01).

Conclusion

Body mass index gain in adulthood is associated with poor overall survival, and maintaining a normal body weight throughout adulthood is associated with the best overall survival among esophageal adenocarcinoma patients, independent of BMI at diagnosis.

Serum Levels of 25-Hydroxyvitamin D at Diagnosis Are Not Associated with Overall Survival in Esophageal Adenocarcinoma

BACKGROUND

Higher levels of circulating 25-hydroxyvitamin D [25(OH)D] are associated with longer survival in several cancers, but the results have differed across cancer sites. The association between serum 25(OH)D levels and overall survival (OS) time in esophageal adenocarcinoma remains unclear.

METHODS

We utilized serum samples from 476 patients with primary esophageal adenocarcinoma, recruited from Massachusetts General Hospital (Boston, MA) between 1999 and 2015. We used log-rank tests to test the difference in survival curves across quartiles of 25(OH)D levels and extended Cox modeling to estimate adjusted HRs. We tested for interactions between clinical stage or BMI on the association between 25(OH)D and OS. We additionally performed sensitivity analyses to determine whether race or timing of blood draw (relative to treatment) affected these results.

RESULTS

We found no evidence that survival differed across quartiles of 25(OH)D (log rank P = 0.48). Adjusting for confounders, we found no evidence that the hazard of death among the highest quartile of 25(OH)D (quartile 1) differed from any other quartile [quartile 2 HR = 0.90, 95% confidence interval (CI), 0.67-1.23; quartile 3 HR = 1.03, 95% CI, 0.76-1.38; quartile 4 (lowest) HR = 0.98, 95% CI, 0.72-1.33]. Sensitivity analyses yielded consistent results when accounting for race or time between diagnosis and blood draw. Moreover, we did not find evidence of interaction between 25(OH)D and clinical stage or BMI on OS.

CONCLUSIONS

Serum level of 25(OH)D near time of diagnosis was not associated with OS in patients with esophageal adenocarcinoma.

IMPACT

Screening 25(OH)D levels among patients with esophageal adenocarcinoma at diagnosis is not clinically relevant to their cancer prognosis based on present evidence.

Association Between Single Nucleotide Polymorphisms in PPARA and EPAS1 Genes and High-Altitude Appetite Loss in Chinese Young Men

Appetite loss is a common symptom that occurs in high altitude (HA) for lowlanders. Previous studies indicated that hypoxia is the initiating vital factor of HA appetite loss. PPARA, EPAS1, EGLN1, HIF1A, HIF1AN, and NFE2L2 play important roles in hypoxic responses. We aimed to explore the association of these hypoxia-related gene polymorphisms with HA appetite loss. In this study, we enrolled 416 young men who rapidly ascended to Lhasa (3700 m) from Chengdu (<500m) by plane. PPARA, EPAS1, EGLN1, HIF1A, HIF1AN, and NFE2L2 were genotyped by MassARRAY. Appetite scores were measured to identify HA appetite loss. Logistic regression and multiple genetic models were tested to evaluate the association between the single nucleotide polymorphisms (SNPs) and risk of HA appetite loss in crude and adjusted (age and SaO₂) analysis. Subsequently, Haploview software was used to analyze the linkage disequilibrium (LD), haplotype construction and the association of diverse haplotypes with the risk of HA appetite loss. Our results revealed that allele “A” in PPARA rs4253747 was significantly associated with the increased risk of HA appetite loss. Codominant, dominant, recessive, and log-additive models of PPARA rs4253747 showed the increased risk of HA appetite loss in the crude and adjusted analysis. However, only dominant, overdominant, and log-additive models of EPAS1 rs6756667 showed decreased risk of HA appetite loss in the crude and adjusted analysis. Moreover, the results from haplotype-based test showed that the rs7292407-rs6520015 haplotype “AC” was associated with HA appetite loss in the crude analysis rather than the adjusted analysis. In this study, we first established the association of SNPs in PPARA (rs4253747) and EPAS1 (rs6756667) genes with susceptibility to HA appetite loss in Han Chinese young men. These findings provide novel insights into understanding the mechanisms involved in HA appetite loss.

Interactions Between Genetic Variants and Environmental Factors Affect Risk of Esophageal Adenocarcinoma and Barrett's Esophagus

BACKGROUND & AIMS

Genome-wide association studies (GWAS) have identified more than 20 susceptibility loci for esophageal adenocarcinoma (EA) and Barrett's esophagus (BE). However, variants in these loci account for a small fraction of cases of EA and BE. Genetic factors might interact with environmental factors to affect risk of EA and BE. We aimed to identify single nucleotide polymorphisms (SNPs) that may modify the associations of body mass index (BMI), smoking, and gastroesophageal reflux disease (GERD), with risks of EA and BE.

METHODS

We collected data on single BMI measurements, smoking status, and symptoms of GERD from 2284 patients with EA, 3104 patients with BE, and 2182 healthy individuals (controls) participating in the Barrett's and Esophageal Adenocarcinoma Consortium GWAS, the UK Barrett's Esophagus Gene Study, and the UK Stomach and Oesophageal Cancer Study. We analyzed 993,501 SNPs in DNA samples of all study subjects. We used standard case-control logistic regression to test for gene-environment interactions.

RESULTS

For EA, rs13429103 at chromosome 2p25.1, near the RNF144A-LOC339788 gene, showed a borderline significant interaction with smoking status (P = 2.18×10-7). Ever smoking was associated with an almost 12-fold increase in risk of EA among individuals with rs13429103-AA genotype (odds ratio=11.82; 95% CI, 4.03-34.67). Three SNPs (rs12465911, rs2341926, rs13396805) at chromosome 2q23.3, near the RND3-RBM43 gene, interacted with GERD symptoms (P = 1.70×10-7, P = 1.83×10-7, and P = 3.58×10-7, respectively) to affect risk of EA. For BE, rs491603 at chromosome 1p34.3, near the EIF2C3 gene, and rs11631094 at chromosome 15q14, at the SLC12A6 gene, interacted with BMI (P = 4.44×10-7) and pack-years of smoking history (P = 2.82×10-7), respectively.

CONCLUSION

The associations of BMI, smoking, and GERD symptoms with risks of EA and BE appear to vary with SNPs at chromosomes 1, 2, and 15. Validation of these suggestive interactions is warranted.

Exposure to phthalates in patients with diabetes and its association with oxidative stress, adiponectin, and inflammatory cytokines

Epidemiologic studies have revealed higher concentrations of the metabolites of phthalic acid esters (mPAEs) in patients with type 2 diabetes. On the other hand, oxidative stress, adiponectin, and inflammatory cytokines play important roles in the pathogenesis of diabetes and its complications. However, little information is known about the association between exposure to PAEs and these physiological parameters. Hence, paired urine and blood samples were collected from a total of 329 volunteers, and 11 main mPAEs and malondialdehyde (MDA), as a biomarker of oxidative stress, were measured in the urine samples. Serum adiponectin and tumor necrosis factor-α (TNF-α), a biomarker of inflammation, were also measured. Multivariable linear regression was used to assess the association between urinary mPAEs and these physiological parameters in the total subjects and subjects stratified by age, sex, and body mass index (BMI) to elucidate their possible interactions. All 11 mPAEs were detected in the urine with detection rates of 42.9%-100% and geometric means of 0.30-54.52ng/mL (0.44-79.93μg/g creatinine). The mPAEs were all positively associated with MDA levels. There were significant positive associations between monomethyl phthalate (mMP) and TNF-α, and inverse associations between mMP and adiponectin levels. In the stratified analysis, there were age-, sex-, and BMI-specific differences for these associations. The positive associations between mPAEs and MDA were insignificant in some subgroups, especially in the larger age group. However, in the larger BMI group, summed metabolites of di-(2-ethylhexyl) phthalate (∑DEHP) and mono(2-ethylhexyl) phthalate were positively associated with TNF-α, and the concentrations of ∑DEHP were negatively associated with adiponectin. Our findings suggested that PAE exposure is associated with oxidative stress, adiponectin, and inflammatory cytokines in diabetic patients; further studies on toxicology and a comparison with general population are needed.

Use of chromatographic and electrophoretic tools for assaying elastase, collagenase, hyaluronidase, and tyrosinase activity

Elastase, collagenase, hyaluronidase and tyrosinase, are very interesting enzymes due to their direct implication in skin aging and as therapeutic hits. Different techniques can be used to study these enzymes and to evaluate the influence of effectors on their kinetics. Nowadays, analytical techniques have become frequently used tools for miniaturizing enzyme assays. The main intention of this article is to review chromatographic and electrophoretic tools that study the four enzymes above mentioned. More specifically, the use of high-performance liquid chromatography and capillary electrophoresis and their derivative techniques for monitoring these enzymes will be investigated. The advantages and limitations of these assays will also be discussed. The original use of microscale thermophoresis and thin layer chromatography in this domain will also be covered.

A newly identified susceptibility locus near FOXP1 modifies the association of gastroesophageal reflux with Barrett's esophagus

BACKGROUND

Important risk factors for esophageal adenocarcinoma and its precursor, Barrett's esophagus, include gastroesophageal reflux disease, obesity, and cigarette smoking. Recently, genome-wide association studies have identified seven germline single-nucleotide polymorphisms (SNP) that are associated with risk of Barrett's esophagus and esophageal adenocarcinoma. Whether these genetic susceptibility loci modify previously identified exposure-disease associations is unclear.

METHODS

We analyzed exposure and genotype data from the BEACON Consortium discovery phase GWAS, which included 1,516 esophageal adenocarcinoma case patients, 2,416 Barrett's esophagus case patients, and 2,187 control participants. We examined the seven newly identified susceptibility SNPs for interactions with body mass index, smoking status, and report of weekly heartburn or reflux. Logistic regression models were used to estimate ORs for these risk factors stratified by SNP genotype, separately for Barrett's esophagus and esophageal adenocarcinoma.

RESULTS

The odds ratio for Barrett's esophagus associated with at least weekly heartburn or reflux varied significantly with the presence of at least one minor allele of rs2687201 (nominal P = 0.0005, FDR = 0.042). ORs (95% CIs) for weekly heartburn or reflux among participants with 0, 1, or 2 minor alleles of rs2687201 were 6.17 (4.91-7.56), 3.56 (2.85-4.44), and 3.97 (2.47-6.37), respectively. No statistically significant interactions were observed for smoking status and body mass index.

CONCLUSION

Reflux symptoms are more strongly associated with Barrett's esophagus risk among persons homozygous for the major allele of rs2687201, which lies approximately 75 kb downstream of the transcription factor gene FOXP1.

IMPACT

The novel gene-exposure interaction discovered in this study provides new insights into the etiology of esophageal adenocarcinoma.

Gene-environment interactions in inflammatory bowel disease pathogenesis

PURPOSE OF REVIEW

Inflammatory bowel disease (IBD) has long been known to have genetic risk factors because of increased prevalence in the relatives of affected individuals. However, genome-wide association studies have only explained limited heritability in IBD. The observed globally rising incidence of IBD has implicated the role of environmental factors. The hidden unexplained heritability remains to be explored.

RECENT FINDINGS

Recent aggregate evidence has highlighted the extent and nature of host genome-microbiome associations, a key next step in understanding the mechanisms of pathogenesis in IBD. An individual's gut microbiota is shaped not only by genetic but also by environmental factors like diet. Minimizing exposure of the intestinal lumen to selected food items has shown to prolong the remission state of IBD. Among a genetically susceptible host, the shift of gut microbiota (or 'dysbiosis') can lead to increasing the susceptibility to IBD. With the advances in high-throughput large-scale 'omics' technologies in combination with creative data mining and system biology-based network analyses, the complexity of biological functional networks behind the cause of IBD has become more approachable. Therefore, the hidden heritability in IBD has become more explainable, and can be attributable to the changing environmental factors, epigenetic modifications, and gene-host microbial ('in-vironmental') or gene-extrinsic environmental interactions.

SUMMARY

This review discusses the perspectives of relevance to clinical translation with emphasis on gene-environment interactions. No doubt, the use of system-based approaches will lead to the development of alternative, and hopefully better, diagnostic, prognostic, and monitoring tools in the management of IBD.

Domestic incense burning and nasopharyngeal carcinoma: a case-control study in Hong Kong Chinese

Incense burning is a powerful producer of carcinogens and has been considered as a risk factor for nasopharyngeal carcinoma (NPC). We conducted a case-control study and case-only analyses to investigate the effect of incense burning and its interaction with genetic background on NPC risk among Hong Kong Chinese. Between June 2010 and December 2012, we recruited 352 incident cases of NPC and 410 controls. We collected information on lifelong practice of domestic incense burning via interviews and genotyped 80 single nucleotide polymorphisms (SNPs) in DNA repair genes. We observed an increased NPC risk associated with daily burning in women [Adjusted OR = 2.49, 95% confidence interval (CI): 1.33, 4.66] but not in men. The adjusted OR for daily burning with poor ventilation was 2.08 (95% CI: 1.02, 4.24), while that with good ventilation was 1.35 (95% CI: 0.92, 1.98). Interactions between 2 SNPs (rs2074517 and rs4771436) and incense burning were significantly associated with NPC risk and tended to have a SNP exposure-response effect. Evidence for gene-environment interactions supported the knowledge that NPC is a multi-factorial disease resulting from the joint effects of environmental exposures and inherited susceptibility.

Neoangiogenesis. Assessment in Esophageal Adenocarcinomas

Esophageal cancer has always been subject of research for various studies. According to some authors, esophageal cancer represents the 10th leading cause of cancer in the world with a 5-year survival of 10 %. In terms of anatomopathological form of the esophageal neoplasia, the literature mainly describes two major pathological types: adenocarcinoma and esophageal squamous cell carcinoma. Lately there has been an increased incidence of esophageal adenocarcinoma. The aim of the present work was to study neoangiogenesis in esophageal adenocarcinomas. The study was conducted on 40 cases diagnosed and surgically treated. Subsequently, fragment processing was performed using various immunohistochemical staining and marking with CD34 and p53 antigen. Later, quantitative measurements were performed, and images were taken using a microscope imaging system. In the end of the procedures, the professional program PRODIT 5.2. was applied. The study of the vascular system in the esophageal epithelial tumors revealed an axis consisting of three elements which have a mutual induction process: inflammatory infiltrate-neoangiogenesis-fibrosis, with significant differences between the three degrees of differentiation. A significant increase in tumor micro vascular density was present together with the increasing of the histological grading, with an inverse correlation with the degree of differentiation and directly proportional to the risk of malignancy.

Gene-environment interactions in genome-wide association studies: current approaches and new directions

BACKGROUND

Complex psychiatric traits have long been thought to be the result of a combination of genetic and environmental factors, and gene-environment interactions are thought to play a crucial role in behavioral phenotypes and the susceptibility and progression of psychiatric disorders. Candidate gene studies to investigate hypothesized gene-environment interactions are now fairly common in human genetic research, and with the shift toward genome-wide association studies, genome-wide gene-environment interaction studies are beginning to emerge.

METHODS

We summarize the basic ideas behind gene-environment interaction, and provide an overview of possible study designs and traditional analysis methods in the context of genome-wide analysis. We then discuss novel approaches beyond the traditional strategy of analyzing the interaction between the environmental factor and each polymorphism individually.

RESULTS

Two-step filtering approaches that reduce the number of polymorphisms tested for interactions can substantially increase the power of genome-wide gene-environment studies. New analytical methods including data-mining approaches, and gene-level and pathway-level analyses, also have the capacity to improve our understanding of how complex genetic and environmental factors interact to influence psychologic and psychiatric traits. Such methods, however, have not yet been utilized much in behavioral and mental health research.

CONCLUSIONS

Although methods to investigate gene-environment interactions are available, there is a need for further development and extension of these methods to identify gene-environment interactions in the context of genome-wide association studies. These novel approaches need to be applied in studies of psychology and psychiatry.

Challenges and opportunities in genome-wide environmental interaction (GWEI) studies

The interest in performing gene-environment interaction studies has seen a significant increase with the increase of advanced molecular genetics techniques. Practically, it became possible to investigate the role of environmental factors in disease risk and hence to investigate their role as genetic effect modifiers. The understanding that genetics is important in the uptake and metabolism of toxic substances is an example of how genetic profiles can modify important environmental risk factors to disease. Several rationales exist to set up gene-environment interaction studies and the technical challenges related to these studies-when the number of environmental or genetic risk factors is relatively small-has been described before. In the post-genomic era, it is now possible to study thousands of genes and their interaction with the environment. This brings along a whole range of new challenges and opportunities. Despite a continuing effort in developing efficient methods and optimal bioinformatics infrastructures to deal with the available wealth of data, the challenge remains how to best present and analyze genome-wide environmental interaction (GWEI) studies involving multiple genetic and environmental factors. Since GWEIs are performed at the intersection of statistical genetics, bioinformatics and epidemiology, usually similar problems need to be dealt with as for genome-wide association gene-gene interaction studies. However, additional complexities need to be considered which are typical for large-scale epidemiological studies, but are also related to "joining" two heterogeneous types of data in explaining complex disease trait variation or for prediction purposes.