The genetics of nicotine dependence: Relationship to pancreatic cancer

Association of NRG3 and ERBB4 gene polymorphism with nicotine dependence in Turkish population

BACKGROUND

Nicotine dependence (ND) is characterized by regular smoking, anxiety, irritation, difficulty concentrating, impatience, restlessness, tremor, dizziness, hunger, nicotine demand, and the individual's reluctance to quit despite knowing the health risks of smoking. Recently, it has been reported that the Neuregulin 3 (NRG3)/Erb-B2 receptor tyrosine kinase 4 (ERBB4) signaling pathway plays a role in ND. NRG3, which is activated after nicotine intake, binds to ERBB4 and causes GABA release. GABA reduces anxiety and tension, which are one of the nicotine withdrawal symptoms. Therefore we aimed to investigate the relationship between NRG3 and ERBB4 gene polymorphisms and ND.

MATERIALS AND METHODS

The study population was comprised of patients with ND (n = 200) and healthy non-smoker control subjects (n = 200) who were matched for age, sex, and compared for comorbidity factors such as alcohol, smoking, duration, and education (age range 18-60). Genotypes were detected by Real-Time PCR using TaqMan technology. The Fagerström Nicotine Dependence Test (FTND) score was 5 and above for the patient group and 0 for the control group. DNA was obtained from whole peripheral blood and six polymorphisms of Neuregulin 3 (NRG3) (rs1836724, rs7562566, and rs10048757) and Erb-B2 Receptor Tyrosine Kinase 4 (ERBB4) (rs1764072, rs6584400, and rs10883934) genes were analyzed by real-time PCR method.

RESULTS

Our findings show that the six selected SNPs are not significantly associated with ND in the Turkish population and no correlation with dependence levels (p > 0.05).

CONCLUSION

Although our findings do not show a relationship between ND and these polymorphisms, it is the first study to investigate these single nucleotide polymorphisms (SNPs) for the first time in ND and to find some genotypes in the Turkish population when compared to other populations. Also, our findings are important in terms of their contribution to the literature and forensic genetics.

The stem cell-specific intermediate filament nestin missense variation p.A1199P is associated with pancreatic cancer

The intermediate filament nestin is upregulated in stem/progenitor cells and cancers, and regulates cell proliferation, migration, invasion and stemness. The present study comparatively analyzed serial autopsies of Japanese patients (n=2,206; males, 1,225; females, 981; median, 80.7 years old; range, 33-104 years old) with malignant tumors of whole organs, with respect to the clinical information, and 5 single nucleotide polymorphisms of the nestin gene. p.A1199P associated with pancreatic cancer (odds ratio, 4.4; 95% confidence interval, 1.9-10.0, P=0.001) while it did not associate with malignant neoplasms in other organs. p.A1199P did not associate with precancerous lesions of the pancreas. Single nucleotide polymorphisms of nestin were not associated with sex, drinking, smoking, or body weight. In conclusion, the amino acid 1,199 of nestin is localized in the tail structure of the filament and polymerizes with other intermediate filament proteins. The present results suggest that missense variations of nestin affect pancreatic carcinogenesis in Japanese patients.

To quit or not: Vulnerability of women to smoking tobacco

Tobacco smoking is currently on the rise among women, and can pose a greater health risk. In order to understand the nature of the increase in smoking prevalence among women, we focused on the vulnerability of women to smoking behaviors--smoking cessation or tobacco addiction--and performed a systematic review of the socioeconomic and intrinsic factors as well as tobacco ingredients that affect women's susceptibility to smoking tobacco. We observed that nicotine and other tobacco components including cocoa-relatives, licorice products, and menthol aggravate tobacco addiction in women rather than in men. Various genetic and epigenetic alterations in dopamine pathway and the pharmaco-kinetics and -dynamic factors of nicotine also showed potential evidences for high susceptibility to tobacco addiction in women. Therefore, we suggest systemic approaches to prevent tobacco smoking-related health risks, considering gene-environment-gender interaction.

Association of A118G polymorphism in the μ-opioid receptor gene with smoking behaviors: a meta-analysis

Many studies have investigated the association between the A118G polymorphism in the μ-opioid receptor gene and smoking behaviors, but the results remain controversial. This meta-analysis aimed to derive a more reliable estimate of the effect of the A118G polymorphism on smoking behaviors. We systematically searched the PubMed/Medline, Embase and Web of Science databases for eligible articles published up to October 23, 2014. A total of six studies were selected. Odds ratios (ORs) as well as their corresponding 95% confidence intervals (CIs) were used to estimate the association between A118G polymorphism and smoking behaviors in four genetic models. Heterogeneity analysis and publication bias were also performed. Subgroup analysis was conducted according to different ethnicities. The meta-analysis was performed using either a fixed- or random-effects model as deemed appropriate. In the result of the meta-analysis, a significant association was detected in the dominant model in the Caucasian subgroup (OR = 3.26, 95% CI = 2.65-4.05). This result indicated that Caucasians carrying the G allele (AG + GG) of the A118G polymorphism in the μ-opioid receptor gene were more likely to be addicted to smoking compared with those with the AA homozygote. However, no significant association was found in other genetic models.

Associations between the orexin (hypocretin) receptor 2 gene polymorphism Val308Ile and nicotine dependence in genome-wide and subsequent association studies

Background

Many genetic and environmental factors are involved in the etiology of nicotine dependence. Although several candidate gene variations have been reported by candidate gene studies or genome-wide association studies (GWASs) to be associated with smoking behavior and the vulnerability to nicotine dependence, such studies have been mostly conducted with subjects with European ancestry. However, genetic factors have rarely been investigated for the Japanese population as GWASs. To elucidate genetic factors involved in nicotine dependence in Japanese, the present study comprehensively explored genetic contributors to nicotine dependence by using whole-genome genotyping arrays with more than 200,000 markers in Japanese subjects.

Results

The subjects for the GWAS and replication study were 148 and 374 patients, respectively. A two-stage GWAS was conducted using the Fagerström Test for Nicotine Dependence (FTND), Tobacco Dependence Screener (TDS), and number of cigarettes smoked per day (CPD) as indices of nicotine dependence. For the additional association analyses, patients who underwent major abdominal surgery, patients with methamphetamine dependence/psychosis, and healthy subjects with schizotypal personality trait data were recruited. Autopsy specimens with various diseases were also evaluated. After the study of associations between more than 200,000 marker single-nucleotide polymorphisms (SNPs) and the FTND, TDS, and CPD, the nonsynonymous rs2653349 SNP (located on the gene that encodes orexin [hypocretin] receptor 2) was selected as the most notable SNP associated with FTND, with a p value of 0.0005921 in the two-stage GWAS. This possible association was replicated for the remaining 374 samples. This SNP was also associated with postoperative pain, the initiation of methamphetamine use, schizotypal personality traits, and susceptibility to goiter.

Conclusions

Although the p value did not reach a conventional genome-wide level of significance in our two-stage GWAS, we obtained significant results in the subsequent analyses that suggest that the rs2653349 SNP (Val308Ile) could be a genetic factor that is related to nicotine dependence and possibly pain, schizotypal personality traits, and goiter in the Japanese population.

Electronic supplementary material

The online version of this article (doi:10.1186/s13041-015-0142-x) contains supplementary material, which is available to authorized users.

The Role of nAChR and Calcium Signaling in Pancreatic Cancer Initiation and Progression

Pancreatic cancer shows a strong correlation with smoking and the current therapeutic strategies have been relatively ineffective in improving the survival of patients. Efforts have been made over the past many years to understand the molecular events that drive the initiation and progression of pancreatic cancer, especially in the context of smoking. It has become clear that components of tobacco smoke not only initiate these cancers, especially pancreatic ductal adenocarcinomas (PDACs) through their mutagenic properties, but can also promote the growth and metastasis of these tumors by stimulating cell proliferation, angiogenesis, invasion and epithelial-mesenchymal transition. Studies in cell culture systems, animal models and human samples have shown that nicotinic acetylcholine receptor (nAChR) activation enhances these tumor-promoting events by channeling signaling through multiple pathways. In this context, signaling through calcium channels appear to facilitate pancreatic cancer growth by itself or downstream of nAChRs. This review article highlights the role of nAChR downstream signaling events and calcium signaling in the growth, metastasis as well as drug resistance of pancreatic cancer.

Targeting NK-1 Receptors to Prevent and Treat Pancreatic Cancer: a New Therapeutic Approach

Pancreatic cancer (PC) is the fourth leading cause of cancer related-deaths in both men and women, and the 1- and 5-year relative survival rates are 25% and 6%, respectively. It is known that smoking, alcoholism and psychological stress are risk factors that can promote PC and increase PC progression. To date, the prevention of PC is crucial because there is no curative treatment. After binding to the neurokinin-1 (NK-1) receptor (a receptor coupled to the stimulatory G-protein Gαs that activates adenylate cyclase), the peptide substance P (SP)-at high concentrations-is involved in many pathophysiological functions, such as depression, smoking, alcoholism, chronic inflammation and cancer. It is known that PC cells and samples express NK-1 receptors; that the NK-1 receptor is overexpressed in PC cells in comparison with non-tumor cells, and that nanomolar concentrations of SP induce PC cell proliferation. By contrast, NK-1 receptor antagonists exert antidepressive, anxiolytic and anti-inflammatory effects and anti-alcohol addiction. These antagonists also exert An antitumor action since in vitro they inhibit PC cell proliferation (PC cells death by apoptosis), and in a xenograft PC mouse model they exert both antitumor and anti-angiogenic actions. NK-1 receptor antagonists could be used for the treatment of PC and hence the NK-1 receptor could be a new promising therapeutic target in PC.

Association between common genetic variants in the opioid pathway and smoking behaviors in Chinese men

Background

There is biological evidence that the brain opioidergic system plays a critical role in the addictive properties of nicotine. The purpose of the present study was to examine the associations of single nucleotide polymorphisms (SNPs) in the genes encoding mu-opioid receptor (MOR) and the MOR-interacting proteins (including OPRM1, ARRB2, and HINT1) with smoking behaviors in Chinese men.

Methods

A total of 284 subjects (including current and ex-smokers) were recruited. Special questionnaires were used to assess smoking behaviors including age of smoking initiation, daily cigarette consumption, and Fagerström test for nicotine dependence (FTND) score. Participant samples were genotyped for six SNPs in the opioid pathway genes: rs1799971 in OPRM1, rs1045280, rs2036657 and rs3786047 in ARRB2, rs3852209 and rs2278060 in HINT1. Linear and logistic regression models were used to determine single-locus and haplotype-based association analyses.

Results

There was no significant association between any of SNPs analyzed and smoking behaviors. Logistic regression analyses under dominant, recessive, and additive models showed no significant associations of the six SNPs with smoking status (current vs. ex-smokers). After adjustment for age at enrollment and smoking initiation age, HINT1 rs3852209 was significantly associated with smoking status with an OR of 0.54 (95% CI, 0.31-0.95; P = 0.03) under dominant inheritance model. No haplotypes in ARRB2 or HINT1 were related to smoking status.

Conclusions

The present study indicates no significant association between common genetic variations in MOR and MOR-interacting proteins and smoking behaviors in Chinese men, and gives suggestive evidence that HINT1 rs3852209 may be related to smoking status. The findings require confirmation from further studies in additional larger samples.

Effects of chronic nicotine on the autocrine regulation of pancreatic cancer cells and pancreatic duct epithelial cells by stimulatory and inhibitory neurotransmitters

Pancreatic ductal adenocarcinoma (PDAC) has a mortality rate near 100%. Smoking is a documented risk factor. However, the mechanisms of smoking-associated pancreatic carcinogenesis are poorly understood. We have shown that binding of nicotine to nicotinic acetylcholine receptors (nAChRs) expressing subunits α7, α3 and α5 in PDAC and pancreatic duct epithelial cells in vitro triggered the production of the neurotransmitters noradrenaline and adrenaline by these cells. In turn, this autocrine catecholamine loop significantly stimulated cell proliferation via cyclic adenosine 3',5'-monophosphate-dependent signaling downstream of beta-adrenergic receptors. However, the observed responses only represent acute cellular reactions to single doses of nicotine whereas nicotine exposure in smokers is chronic. Using the PDAC cell lines BxPC-3 and Panc-1 and immortalized pancreatic duct epithelial cell line HPDE6-C7, our current experiments reveal a significant sensitization of the nAChR-driven autocrine catecholamine regulatory loop in cells pre-exposed to nicotine for 7 days. The resulting increase in catecholamine production was associated with significant inductions in the phosphorylation of signaling proteins ERK, CREB, Src and AKT, upregulated protein expression of nAChR subunits α3, α4, α5 and α7 and increased responsiveness to nicotine in 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide and cell migration assays. All three cell lines produced the inhibitory neurotransmitter γ-aminobutyric acid, an activity inhibited by gene knockdown of the α4β2nAChR and suppressed by chronic nicotine via receptor desensitization. All of the observed adverse effects of chronic nicotine were reversed by treatment of the cells with γ-aminobutyric acid, suggesting the potential usefulness of this agent for the improvement of PDAC intervention strategies in smokers.

The role of tobacco-derived carcinogens in pancreas cancer

The extremely poor outcome from pancreas cancer is well known. However, its aetiology less well appreciated, and the molecular mechanisms underlying this are poorly understood. Tobacco usage is one of the strongest risk factors for this disease, and this is a completely avoidable hazard. In addition, there are well described hereditary diseases which predispose, and familial pancreas cancer. We have sought here to summarise the role of tobacco-derived carcinogens and the mode of their tumorigenic action on the pancreas. There is compelling evidence from animal and human studies (laboratory including cell line studies and epidemiologic) that tobacco derived carcinogens cause pancreas cancer. However, the manner in which they do so is not entirely apparent. There is also compelling evidence that synergism with genetic and other life-style factors-like diet obesity-results in a multifactorial causation of the disease. Ascertaining the role of tobacco carcinogens in the development of this cancer and their interaction with other risk factors will enable novel therapeutic and preventative strategies to improve outcome from this appalling malignancy.

Genome-wide association study of pancreatic cancer in Japanese population

Pancreatic cancer shows very poor prognosis and is the fifth leading cause of cancer death in Japan. Previous studies indicated some genetic factors contributing to the development and progression of pancreatic cancer; however, there are limited reports for common genetic variants to be associated with this disease, especially in the Asian population. We have conducted a genome-wide association study (GWAS) using 991 invasive pancreatic ductal adenocarcinoma cases and 5,209 controls, and identified three loci showing significant association (P-value<5×10⁻⁷) with susceptibility to pancreatic cancer. The SNPs that showed significant association carried estimated odds ratios of 1.29, 1.32, and 3.73 with 95% confidence intervals of 1.17–1.43, 1.19–1.47, and 2.24–6.21; P-value of 3.30×10⁻⁷, 3.30×10⁻⁷, and 4.41×10⁻⁷; located on chromosomes 6p25.3, 12p11.21 and 7q36.2, respectively. These associated SNPs are located within linkage disequilibrium blocks containing genes that have been implicated some roles in the oncogenesis of pancreatic cancer.

Familial association of pancreatic cancer with other malignancies in Swedish families

Background:

The aim of this study was to characterise the familial association of pancreatic cancer with other malignancies.

Methods:

Relative risks (RRs) of pancreatic cancer according to family history of cancer were calculated using the updated Swedish Family-Cancer Database, which includes over 11.5 million individuals. Estimates were based on Poisson regression. RRs of tumours for individuals with a parental history of pancreatic cancer were also estimated.

Results:

The risk of pancreatic cancer was elevated in individuals with a parental history of cancers of the liver (RR 1.41; 95% CI 1.10–1.81), kidney (RR 1.37; 95% CI 1.06–1.76), lung (RR 1.50; 95% CI 1.27–1.79) and larynx (RR 1.98; 95% CI 1.19–3.28). Associations were also found between parental history of pancreatic cancer and cancers of the small intestine, colon, breast, lung, testis and cervix in offspring. There was an increased risk of pancreatic cancer associated with early-onset breast cancer in siblings.

Conclusion:

Pancreatic cancer aggregates in families with several types of cancer. Smoking may contribute to the familial aggregation of pancreatic and lung tumours, and the familial clustering of pancreatic and breast cancer could be partially explained by inherited mutations in the BRCA2 gene.

Does quality of observational studies affect the results of a meta-analysis?: the case of cigarette smoking and pancreatic cancer

OBJECTIVES

A meta-analysis of observational studies on association between cigarette smoking and pancreatic cancer was performed to focus, particularly, on the role of the studies' quality in affecting meta-analysis results.

METHODS

A bibliographic search was carried out on PubMed and EMBASE databases until February 15, 2008. Key words were "pancreatic neoplasms," "pancreatic cancer," "smoking," "smoke," "cigarette," "case-control studies," and "cohort studies." Studies about cigarette smoking and pancreatic cancer were selected and assessed on quality. STATA 9.0 was used.

RESULTS

Six cohort studies and 24 case-control studies were selected, with median quality scores of 8 (range, 3) and 10 (range, 8), respectively. Pooled case-control studies' odds ratio (OR) and cohort studies' risk ratio were, respectively, 1.45 (95% confidence interval [CI], 1.33-1.57) and 1.78 (95% CI, 1.64-1.92). After stratifying for quality scoring, high-quality-scored case-control studies yielded an OR of 1.38 (95% CI, 1.27-1.49), whereas the others gave an OR of 1.52 (95% CI, 1.34-1.73). The results of meta-analysis for cohort studies showed a risk ratio of 1.74 (95% CI, 1.61-1.90) and of 2.10 (95% CI, 1.64-2.67), respectively, for high- and low-quality score studies.

CONCLUSIONS

There is evidence that cigarette smoking is an important risk factor for pancreatic cancer, but the estimate of the association greatly relies on the studies' quality.

Basic principles and technologies for deciphering the genetic map of cancer

The progress achieved in the field of genomics in recent years is leading medicine to adopt a personalized model in which the knowledge of individual DNA alterations will allow a targeted approach to cancer. Using pancreatic cancer as a model, we discuss herein the fundamentals that need to be considered for the high throughput and global identification of mutations. These include patient-related issues, sample collection, DNA isolation, gene selection, primer design, and sequencing techniques. We also describe the possible applications of the discovery of DNA changes to the approach of this disease and cite preliminary efforts where the knowledge has been translated into the clinical or preclinical setting.

Electrical Stimulation-Induced Release of β-Endorphin from Genetically Modified Neuro-2a Cells

The quantity of therapeutic gene products released from genetically engineered cells can be controlled externally at different levels. The widely used approach of controlling expression, however, generally has the disadvantage that chemical substances must be applied for stimulation. An alternative strategy aims at controlling gene products at posttranslational levels such as secretion. The secretion of a therapeutic agent can be regulated if the agent is targeted to the regulated secretory pathway and stored in the secretory granules until its release. In this article we address the question of whether the release of β-endorphin, an opioid with a potent analgesic effect, could be induced by electrically stimulating stably transfected Neuro-2a cells. Throughout this study we used the human proopiomelanocortin (POMC) gene, which is the precursor molecule for human β-endorphin. We analyzed its subcellular localization and found it in the regulated secretory pathway in Neuro-2a cells. Using electrical field stimulation we were able to identify a stimulation pattern that significantly increased the release of β-endorphin-immunoreactive material, although to a limited extent. This result indicates that electrical stimulation of secretion could be used to manipulate the amount of a therapeutic agent released from transplanted cells.

Expression of phosphorylated Akt in oral carcinogenesis and its induction by nicotine and alkaline stimulation

BACKGROUND

In Taiwan, it is well documented that cigarette smoking and areca nut chewing contribute to the risk of oral squamous cell carcinoma (OSCC). The role of phosphorylated Akt (p-Akt) in oral carcinogenesis induced by nicotine and alkaline environments was investigated.

METHOD

Immunohistochemistry (IHC) was used to detect p-Akt expression in cancerous (n = 30) precancerous (n = 30), and normal mucosa tissues (n = 10). Western blotting was used to detect time-dependent induction of p-Akt by 100 microM nicotine in normal human bronchial epithelial cell (NHBE), normal human oral keratinocytes (NHOK), immortalized human epithelial cells (HaCaT) and OEC-M1 cells, dose-dependent induction of p-Akt in OEC-M1 and HaCaT cells and pH effect of p-Akt in OEC-M1. The unpaired t-test and the Fisher's exact test were used to analyze the p-Akt immunoreactivity in various groups and its association with clinicopathological parameters.

RESULTS

Higher p-Akt expression in cancerous group than in normal mucosa (P = 0.0002) and precancerous (P = 0.0049) groups was observed. A time-dependent increase in p-Akt in the NHBE, NHOK, HaCaT and OEC-M1 cell lines was observed with 100 microM nicotine treatment. The dose-dependent increase in p-Akt by nicotine treatment in HaCaT and OEC-M1 cells was obviously observed. Higher p-Akt expression in more alkaline environment (pH 8.0) was observed than at pH 7.4 in OEC-M1 cells.

CONCLUSION

A potential role for increased p-Akt may relate to the dose and time of nicotine use. The potential role of an alkaline environment to enhance nicotine-related oral carcinogenesis may exist.