A cell-based approach to study changes in the pancreas following nicotine exposure in an animal model of injury

Cholinergic Mechanisms in Gastrointestinal Neoplasia

Acetylcholine-activated receptors are divided broadly into two major structurally distinct classes: ligand-gated ion channel nicotinic and G-protein-coupled muscarinic receptors. Each class encompasses several structurally related receptor subtypes with distinct patterns of tissue expression and post-receptor signal transduction mechanisms. The activation of both nicotinic and muscarinic cholinergic receptors has been associated with the induction and progression of gastrointestinal neoplasia. Herein, after briefly reviewing the classification of acetylcholine-activated receptors and the role that nicotinic and muscarinic cholinergic signaling plays in normal digestive function, we consider the mechanics of acetylcholine synthesis and release by neuronal and non-neuronal cells in the gastrointestinal microenvironment, and current methodology and challenges in measuring serum and tissue acetylcholine levels accurately. Then, we critically evaluate the evidence that constitutive and ligand-induced activation of acetylcholine-activated receptors plays a role in promoting gastrointestinal neoplasia. We focus primarily on adenocarcinomas of the stomach, pancreas, and colon, because these cancers are particularly common worldwide and, when diagnosed at an advanced stage, are associated with very high rates of morbidity and mortality. Throughout this comprehensive review, we concentrate on identifying novel ways to leverage these observations for prognostic and therapeutic purposes.

The Risk Factors for Progression to Chronic Pancreatitis in Patients with Past-History of Acute Pancreatitis: A Retrospective Analysis Based on Mechanistic Definition

Background: According to the mechanistic definition, the history of acute pancreatitis (AP) is a risk factor for chronic pancreatitis (CP). However, the etiology and severity of previous AP involved in the progression to CP have not been clarified. Here, we investigated risk factors for the progression to CP in patients with past-history of AP. Methods: Sixty-four patients with AP who were followed-up for at least two years at our institution between April 2009 and March 2017 were enrolled. The multivariate analysis was performed based on the risk factors extracted by univariate analysis. Results: Among the 64 patients, 13 patients (20.3%) progressed to CP (PCP group), while 48 did not (non-PCP group). Regarding the etiology of AP, rate of alcohol AP was significantly higher in the PCP group (76.9% vs. 33.3%, p = 0.003). In univariate analysis, smoking, number of previous AP, and alcohol consumption and drinking habits (Alcohol Use Disorders Identification Test-Concise; AUDIT-C) were identified as factors associated with progression to CP. Furthermore, multivariate analysis showed that AUDIT-C ≥ 6 points (male) and 4 points (female) after AP was a significant risk factor for CP (p = 0.003). Conclusions: Our results indicated that AUDIT-C ≥ 6 points (male) and 4 points (female) after AP was a risk factor in the process of progression to CP in patients with past-history of AP.

Risk Factors for Recurrent Pancreatitis After First Episode of Acute Pancreatitis

Background

Methods

Results

Conclusion

Tobacco smoking and the risk of pancreatitis: A systematic review and meta-analysis of prospective studies

BACKGROUND

Tobacco smoking has been associated with increased risk of pancreatitis in several studies, however, not all studies have found an association and it is unclear whether there is a dose-response relationship between increasing amount of tobacco smoked and pancreatitis risk. We conducted a systematic review and meta-analysis of prospective studies on tobacco smoking and pancreatitis to clarify the association.

METHODS

PubMed and Embase databases were searched for relevant studies up to April 13th^, 2019. Prospective studies that reported adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for the association between tobacco smoking and pancreatitis were included and summary RRs were calculated using a random effects model.

RESULTS

Ten prospective studies were included. The summary RR for acute pancreatitis was 1.49 (95% CI: 1.29-1.72, I² = 68%, n = 7) for current smokers, 1.24 (95% CI: 1.15-1.34, I² = 0%, n = 7) for former smokers, and 1.39 (95% CI: 1.25-1.54, I² = 69%, n = 7) for ever smokers compared to never smokers. Similar results were observed for chronic pancreatitis and acute/chronic pancreatitis combined. The summary RR per 10 cigarettes per day was 1.30 (95% CI: 1.18-1.42, I² = 42%, n = 3) and per 10 pack-years in current smokers was 1.13 (95% CI: 1.08-1.17, I² = 14%, n = 4) for acute pancreatitis and results were similar for chronic pancreatitis and acute/chronic pancreatitis combined.

CONCLUSIONS

These results suggest that tobacco smoking increases the risk of acute and chronic pancreatitis and acute and chronic pancreatitis combined and that there is a dose-response relationship between increasing number of cigarettes and pack-years and pancreatitis risk.

Effects of a natural polyphenol on nicotine-induced pancreatic cancer cell proliferation

INTRODUCTION

Resveratrol (trans-3, 4’, 5-trihydroxystilbene), a phytoalexin derived from the skin of grapes and other fruits, has anti-inflammatory and anti-oxidant effects. Its anti-carcinogenic effects are closely associated with its antioxidant activity; thus, the use of resveratrol as a possible cancer chemo-preventive is considered to be an important area of investigation. In this study we have examined the inhibitory effects of resveratrol in nicotine induced proliferation of pancreatic cancer cells.

METHODS

Cultured AR42J cells were incubated with 100 μM nicotine for 3 min and with 100 μM resveratrol for 30 min, either alone or in combination. Proliferation assays were conducted for a period of 0 to 96 h in serum media, incubated with nicotine and resveratrol, and evaluated by MTT assay. Protein was measured in lysed cells and activation of MAPK signals was measured by western blot using purified p-ERK antibody. Co-localization of activated ERK signals was confirmed by FITC conjugated ERK antibody using immunofluorescence assay and confocal microscopy. Biomarker of lipid peroxidation was determined in cell lysates by malondialdehyde (MDA) bioassay.

RESULTS

Resveratrol significantly suppressed the nicotine-induced proliferation of acinar cells compared to untreated controls (p<0.05). Mitogen activated protein kinase (MAPK) analysis revealed up-regulation of p-ERK expression by nicotine (p<0.05) that was suppressed significantly by resveratrol (p<0.05). Co-localization of activated ERK signals was confirmed by FITC conjugated ERK antibody, and this response was reduced significantly by resveratrol. Nicotine-induced malondialdehyde formation was also suppressed by resveratrol (p<0.05).

CONCLUSIONS

The data suggest that resveratrol suppressed nicotine-induced AR42J cell proliferation. The proliferation of AR42J cells by nicotine is associated with activation of MAPK signals and induction of protein oxidation. Resveratrol suppressed lipid peroxidation and P-ERK activated signals induced by nicotine. We conclude that resveratrol acts as an effective antioxidant in reversing the nicotine induced pancreatic cancer cell proliferation.

Prevalence of Panoramically Imaged Carotid Atheromas in Alcoholic Patients With Chronic Pancreatitis and Comorbid Diabetes

PURPOSE

Men with alcohol-related chronic pancreatitis (ARCP) resulting in type 3c diabetes mellitus (DM) are at a uniquely elevated risk of adverse ischemic events given the role of inflammation in both the underlying disease processes and atherosclerosis. We hypothesized that their panoramic images would show a prevalence of calcified carotid artery atheromas (calcified carotid artery plaques [CCAPs]) significantly more often than a general population of similarly aged men.

PATIENTS AND METHODS

We implemented a retrospective observational study. The sample was composed of male patients older than 30 years having panoramic images. The predictor variable was a diagnosis of ARCP-DM, and the outcome variable was the prevalence rate of CCAPs. The prevalence of CCAPs among the patients with ARCP-DM was then compared with that of a historical general population composed of similarly aged men. Descriptive and bivariate statistics were computed, and the P value was set at .05.

RESULTS

Of the 32 men (mean age, 61.7 ± 11.2 years) with ARCP-DM, 8 (25%) (mean age, 63.3 ± 4.80 years) had atheromas (CCAPs). There was a statistically significant (P < .05) association between a diagnosis of ARCP-DM and the presence of an atheroma on the panoramic image in comparison with the 3% rate manifested by the historical general-population cohort. The presence or absence of classic atherogenic risk factors within the ARCP-DM cohort failed to distinguish between individuals with and individuals without atheroma formation on their panoramic images.

CONCLUSIONS

The results of this study suggest that CCAP, a risk indicator for future adverse cardiovascular events, is frequently seen on the panoramic images of male patients with ARCP-DM. Dentists treating male patients with the disorder must be uniquely vigilant for the presence of these lesions.

Nicotine induces aberrant hypermethylation of tumor suppressor genes in pancreatic epithelial ductal cells

Tobacco smoking is an independent risk factor for the initiation of pancreatic cancer (PC). Hypermethylation of tumor suppressor genes has been demonstrated to be associated with smoking. This study aimed to find the relationship between nicotine exposure and hypermethylation of tumor suppressor genes in normal pancreatic epithelial cells. Human pancreatic epithelial cells ware cultured exposing to nicotine and the methylation status of tumor suppressor genes were detected. Proenkephalin (PENK) was chosen as the target gene and methylation level of PENK promoter region was measured. Expression of DNA methyltransferase (DNMT), nicotine acetylcholine receptor (α7nAChR) and signaling pathway downstream were analyzed. Nicotine induces overexpression of DNMT3A and 3B, and methylated-inactivation of PENK gene in normal pancreatic epithelial cells. An activation of α7nAChR and MAPK signaling pathway has been detected in the nicotine-treated group. Demethylated drug, antagonist of α7nAChR and inhibitor of p38 MAPK is verified to attenuate the overexpression of DNMTs stimulated by nicotine as well as inhibit aberrant hypermethylation-related silence of PENK gene. Nicotine stimulation can induce aberrant hypermethylation of tumor suppressor genes by α7nAChR and MAPK signaling pathway-mediated up-regulation of DNMTs in pancreatic epithelial cells, thus we can provide epigenetic evidence of the mechanisms by which smoking causes pancreatic cancer and find new therapeutic target.

Impact of cigarette smoking on recurrence of hyperlipidemic acute pancreatitis

AIM

To investigate the impact of cigarette smoking on the recurrence rate and recurrence-free survival in patients with hyperlipidemic acute pancreatitis (HLAP).

METHODS

A total of 863 patients were admitted to our hospital for acute pancreatitis (AP) from January 2013 to March 2016, of whom 88 diagnosed with HLAP were enrolled in this retrospective study. Demographic data, medical history, previous episodes of pancreatitis, consumption of alcohol and cigarettes, as well as biochemical and hematological data were carefully recorded for univariate and multivariate analyses. During follow-up, the information on current smoking status and recurrent AP was gathered. Recurrence-free survival (RFS) was calculated using the Kaplan-Meier method, and the differences between groups were compared using the log-rank test.

RESULTS

No significant differences were observed between the three groups in age or medical history of hyperlipidemia, fatty liver, diabetes mellitus, hypertension, or AP. The current smokers had a remarkably higher recurrence rate and a greater incidence of repeated episodes of AP (50.0% and 77.8%, respectively) than non-smokers (9.8% and 39.0%), and these two percentages were reduced to 9.1% and 36.4% for patients who gave up smoking. The median follow-up time was 13.5 mo and HLAP recurred after hospital discharge in 23 (26.1%) patients. Multivariate analysis identified current smoking (HR = 6.3, P = 0.020) as an independent risk factor contributing to HLAP recurrence. Current smokers had significantly worse RFS than non-smokers (23 mo vs 42 mo), but no significant difference was documented between ex-smokers (34 mo) and non-smokers. The RFS was not significantly different between light and heavy smokers.

CONCLUSION

Smoking is associated with worse RFS and an increased rate of HLAP recurrence. Continued smoking correlates with a compromised survival and smoking cessation should be recommended.

β2-adrenogenic signaling regulates NNK-induced pancreatic cancer progression via upregulation of HIF-1α

Cigarette smoking is a risk factor for pancreatic cancer. It is suggested that 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco-specific nitrosamine, mediates the carcinogenic action of cigarette smoking by promoting cancer growth. In the present study, we show that smoking, HIF-1α expression and β2-adrenogenic receptor (β2-AR) expression are negatively correlated with the overall survival of pancreatic cancer patients. Moreover, HIF-1α expression and β2-AR expression are positively correlated with smoking status, different histological differentiation and among the tumor node metastasis (TNM) stages in pancreatic cancer patients. NNK increases HIF-1α expression in pancreatic cancer in vitro and in vivo. Furthermore, knockdown of HIF-1α and ICI118, 551 (a β2-AR selective antagonist) abrogates NNK-induced pancreatic cancer proliferation and invasion in vitro and inhibits NNK-induced pancreatic cancer growth in vivo. However, using CoCl2 (a HIF-1α stabilizing agent which decreases HIF-1α degradation under normoxia conditions) reverses ICI118, 551 induced effects under NNK exposure. Thus, our data indicate that β2-AR signaling regulates NNK-induced pancreatic cancer progression via upregulation of HIF-1α. Taken together, β2-AR signaling and HIF-1α may represent promising therapeutic targets for preventing smoking induced pancreatic cancer progression.

Chronic pancreatitis

Chronic pancreatitis describes a wide spectrum of fibro-inflammatory disorders of the exocrine pancreas that includes calcifying, obstructive, and steroid-responsive forms. Use of the term chronic pancreatitis without qualification generally refers to calcifying chronic pancreatitis. Epidemiology is poorly defined, but incidence worldwide seems to be on the rise. Smoking, drinking alcohol, and genetic predisposition are the major risk factors for chronic calcifying pancreatitis. In this Seminar, we discuss the clinical features, diagnosis, and management of chronic calcifying pancreatitis, focusing on pain management, the role of endoscopic and surgical intervention, and the use of pancreatic enzyme-replacement therapy. Management of patients is often challenging and necessitates a multidisciplinary approach.

Risk of Recurrent Pancreatitis and Progression to Chronic Pancreatitis After a First Episode of Acute Pancreatitis

BACKGROUND & AIMS

Patients with a first episode of acute pancreatitis can develop recurrent or chronic pancreatitis (CP). However, little is known about the incidence or risk factors for these events.

METHODS

We performed a cross-sectional study of 669 patients with a first episode of acute pancreatitis admitted to 15 Dutch hospitals from December 2003 through March 2007. We collected information on disease course, outpatient visits, and hospital readmissions, as well as results from imaging, laboratory, and histology studies. Standardized follow-up questionnaires were sent to all available patients to collect information on hospitalizations and interventions for pancreatic disease, abdominal pain, steatorrhea, diabetes mellitus, medications, and alcohol and tobacco use. Patients were followed up for a median time period of 57 months. Primary end points were recurrent pancreatitis and CP. Risk factors were evaluated using regression analysis. The cumulative risk was assessed using Kaplan-Meier analysis.

RESULTS

Recurrent pancreatitis developed in 117 patients (17%), and CP occurred in 51 patients (7.6%). Recurrent pancreatitis developed in 12% of patients with biliary disease, 24% of patients with alcoholic etiology, and 25% of patients with disease of idiopathic or other etiologies; CP occurred in 3%, 16%, and 10% of these patients, respectively. Etiology, smoking, and necrotizing pancreatitis were independent risk factors for recurrent pancreatitis and CP. Acute Physiology and Chronic Health Evaluation II scores at admission also were associated independently with recurrent pancreatitis. The cumulative risk for recurrent pancreatitis over 5 years was highest among smokers at 40% (compared with 13% for nonsmokers). For alcohol abusers and current smokers, the cumulative risks for CP were similar-approximately 18%. In contrast, the cumulative risk of CP increased to 30% in patients who smoked and abused alcohol.

CONCLUSIONS

Based on a retrospective analysis of patients admitted to Dutch hospitals, a first episode of acute pancreatitis leads to recurrent pancreatitis in 17% of patients, and almost 8% of patients progress to CP within 5 years. Progression was associated independently with alcoholic etiology, smoking, and a history of pancreatic necrosis. Smoking is the predominant risk factor for recurrent disease, whereas the combination of alcohol abuse and smoking produces the highest cumulative risk for chronic pancreatitis.

Nicotinic acetylcholine receptors and cancer

Nicotine, the primary addictive constituent of cigarettes, is believed to contribute to cancer promotion and progression through the activation of nicotinic acetylcholine receptors (nAChRs), which are membrane ligand-gated cation channels. nAChRs activation can be triggered by the neurotransmitter Ach, or certain other biological compounds, such as nicotine. In recent years, genome-wide association studies have indicated that allelic variation in the α5-α3-β4 nAChR cluster on chromosome 15q24-15q25.1 is associated with lung cancer risk. The role of nAChRs in other types of cancer has also been reported. The present review highlights the role of nAChRs in types of human cancer.

Chronic Nicotine Exposure In Vivo and In Vitro Inhibits Vitamin B1 (Thiamin) Uptake by Pancreatic Acinar Cells

Thiamin (vitamin B1), a member of the water-soluble family of vitamins, is essential for normal cellular functions; its deficiency results in oxidative stress and mitochondrial dysfunction. Pancreatic acinar cells (PAC) obtain thiamin from the circulation using a specific carrier-mediated process mediated by both thiamin transporters -1 and -2 (THTR-1 and THTR-2; encoded by the SLC19A2 and SLC19A3 genes, respectively). The aim of the current study was to examine the effect of chronic exposure of mouse PAC in vivo and human PAC in vitro to nicotine (a major component of cigarette smoke that has been implicated in pancreatic diseases) on thiamin uptake and to delineate the mechanism involved. The results showed that chronic exposure of mice to nicotine significantly inhibits thiamin uptake in murine PAC, and that this inhibition is associated with a marked decrease in expression of THTR-1 and THTR-2 at the protein, mRNA and hnRNAs level. Furthermore, expression of the important thiamin-metabolizing enzyme, thiamin pyrophosphokinase (TPKase), was significantly reduced in PAC of mice exposed to nicotine. Similarly, chronic exposure of cultured human PAC to nicotine (0.5 μM, 48 h) significantly inhibited thiamin uptake, which was also associated with a decrease in expression of THTR-1 and THTR-2 proteins and mRNAs. This study demonstrates that chronic exposure of PAC to nicotine impairs the physiology and the molecular biology of the thiamin uptake process. Furthermore, the study suggests that the effect is, in part, mediated through transcriptional mechanism(s) affecting the SLC19A2 and SLC19A3 genes.

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.

Epidemiologic and Mechanistic Associations Between Smoking and Pancreatitis

OPINION STATEMENT

Alcohol has long been associated with pancreatitis. Although first described more than three decades ago, smoking has been widely accepted as an important risk factor for all forms of pancreatitis only in the past few years. Empiric data has confirmed smoking as an independent and dose-dependent risk for both acute and chronic pancreatitis. Smoking also increases the risk of recurrences and progression of established chronic pancreatitis. The effects of smoking are enhanced in the presence of alcohol consumption. Indirect evidence suggests that smoking cessation may be beneficial in preventing disease progression. Smoking cessation can therefore be an important strategy for primary as well as secondary prevention of pancreatitis. Therefore, in addition to alcohol, physicians should routinely counsel patients for the benefits of smoking cessation. The mechanisms through which cigarette smoke triggers pathological cellular events, resulting in pancreatitis, are unresolved. Although cigarette smoke contains greater than 4000 compounds, principally nicotine and the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) have been broadly studied with regard to pancreatic diseases. Both nicotine and NNK have been shown to induce morphological changes in the pancreas consistent with those seen in pancreatitis. Furthermore, nicotine affects pancreatic secretion and NNK induces premature zymogen activation, two well-known features of pancreatitis. These cigarette toxins may mediate both pro- and anti-inflammatory pathways and can induce changes in pancreatic acinar cell function at the level of transcription, leading to conditions such as thiamin deficiency and mitochondrial dysfunction. Such circumstances could leave the pancreas prone to the development of pancreatitis. This review summarizes relevant research findings and focuses on the epidemiologic links between smoking and pancreatitis, and the cellular pathways that may be significant in induction and evolution of smoking-related pancreatitis.

Acute pancreatitis

Acute pancreatitis, an inflammatory disorder of the pancreas, is the leading cause of admission to hospital for gastrointestinal disorders in the USA and many other countries. Gallstones and alcohol misuse are long-established risk factors, but several new causes have emerged that, together with new aspects of pathophysiology, improve understanding of the disorder. As incidence (and admission rates) of acute pancreatitis increase, so does the demand for effective management. We review how to manage patients with acute pancreatitis, paying attention to diagnosis, differential diagnosis, complications, prognostic factors, treatment, and prevention of second attacks, and the possible transition from acute to chronic pancreatitis.

Pathologic cellular events in smoking-related pancreatitis

Pancreatitis, a debilitating inflammatory disorder, results from pancreatic injury. Alcohol abuse is the foremost cause, although cigarette smoking has recently surfaced as a distinct risk factor. The mechanisms by which cigarette smoke and its toxins initiate pathological cellular events leading to pancreatitis, have not been clearly defined. Although cigarette smoke is composed of more than 4000 compounds, it is mainly nicotine and the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which have been extensively studied with respect to pancreatic diseases. This review summarizes these research findings and highlights cellular pathways which may be of relevance in initiation and progression of smoking-related pancreatitis.

Treatment options for chronic pancreatitis

This Review covers the latest developments in the treatment options for chronic pancreatitis. Pain is the most frequent and dominant symptom in patients with chronic pancreatitis, which ranges from severe disabling continuous pain to mild pain attacks and pain-free periods. Conventional treatment strategies and recent changes in the treatment of pain in patients with chronic pancreatitis are outlined. The different treatment options for pain consist of medical therapy, endoscopy or surgery. Their related merits and drawbacks are discussed. Finally, novel insights in the field of genetics and microbiota are summarized, and future perspectives are discussed.

Effect of nicotine on exocytotic pancreatic secretory response: role of calcium signaling

Background

Nicotine is a risk factor for pancreatitis resulting in loss of pancreatic enzyme secretion. The aim of this study was to evaluate the mechanisms of nicotine-induced secretory response measured in primary pancreatic acinar cells isolated from Male Sprague Dawley rats. The study examines the role of calcium signaling in the mechanism of the enhanced secretory response observed with nicotine exposure.

Methods

Isolated and purified pancreatic acinar cells were subjected to a nicotine exposure at a dose of 100 μM for 6 minutes and then stimulated with cholecystokinin (CCK) for 30 min. The cell’s secretory response was measured by the percent of amylase released from the cells in the incubation medium Calcium receptor antagonists, inositol trisphosphate (IP₃) receptor blockers, mitogen activated protein kinase inhibitors and specific nicotinic receptor antagonists were used to confirm the involvement of calcium in this process.

Results

Nicotine exposure induced enhanced secretory response in primary cells. These responses remained unaffected by mitogen activated protein kinases (MAPK’s) inhibitors. The effects, however, have been completely abolished by nicotinic receptor antagonist, calcium channel receptor antagonists and inositol trisphosphate (IP₃) receptor blockers.

Conclusions

The data suggest that calcium activated events regulating the exocytotic secretion are affected by nicotine as shown by enhanced functional response which is inhibited by specific antagonists… The results implicate the role of nicotine in the mobilization of both intra- and extracellular calcium in the regulation of stimulus-secretory response of enzyme secretion in this cell system. We conclude that nicotine plays an important role in promoting enhanced calcium levels inside the acinar cell.

Smoking and Pancreatic Disease

Smoking is a major risk factor for chronic pancreatitis and pancreatic cancer. However, the mechanisms through which it causes the diseases remain unknown. In the present manuscript we reviewed the latest knowledge gained on the effect of cigarette smoke and smoking compounds on cell signaling pathways mediating both diseases. We also reviewed the effect of smoking on the pancreatic cell microenvironment including inflammatory cells and stellate cells.

Role of nicotine in gallbladder carcinoma: a preliminary report

OBJECTIVE

To assess the role of nicotine in gallbladder carcinoma and its association with the stage and degree of cancer differentiation.

METHODS

Tissue samples from gallbladder were obtained from 20 patients with gallbladder cancer and 20 age- and gender-matched patients with cholelithiasis who served as the control group. Gallbladder tissue (2 g) was extracted and analyzed for nicotine content using capillary gas chromatography. Nitrogen was used as the carrier gas. Standard curves of nicotine in methanol were made by injecting the internal standards.

RESULTS

A significantly higher tissue nicotine concentration was observed in the gallbladder carcinoma group than that in the control group (179.63 ng/mg vs 6.00 ng/mg, P < 0.001). The stage and degree of cancer differentiation did not seem to affect the nicotine levels. Gallbladder tissue contained a significantly higher nicotine concentration in smokers with cancer compared with those in the control group (1570.00 ng/mg vs 232.25 ng/mg, P < 0.001). Interestingly, non-smokers in cancer group also had a higher nicotine concentration than the control group (161.50 ng/mg vs 4.00 ng/mg, P = 0.002).

CONCLUSION

Nicotine is selectively concentrated in malignant gallbladder tissue irrespective of smoking status, showing its strong association with gallbladder cancer.

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 pathobiological impact of cigarette smoke on pancreatic cancer development (review)

Despite extensive efforts, pancreatic cancer remains incurable. Most risk factors, such as genetic disposition, metabolic diseases or chronic pancreatitis cannot be influenced. By contrast, cigarette smoking, an important risk factor for pancreatic cancer, can be controlled. Despite the epidemiological evidence of the detrimental effects of cigarette smoking with regard to pancreatic cancer development and its unique property of being influenceable, our understanding of cigarette smoke-induced pancreatic carcinogenesis is limited. Current data on cigarette smoke-induced pancreatic carcinogenesis indicate multifactorial events that are triggered by nicotine, which is the major pharmacologically active constituent of tobacco smoke. In addition to nicotine, a vast number of carcinogens have the potential to reach the pancreatic gland, where they are metabolized, in some instances to even more toxic compounds. These metabolic events are not restricted to pancreatic ductal cells. Several studies show that acinar cells are also greatly affected. Furthermore, pancreatic cancer progenitor cells do not only derive from the ductal epithelial lineage, but also from acinar cells. This sheds new light on cigarette smoke-induced acinar cell damage. On this background, our objective is to outline a multifactorial model of tobacco smoke-induced pancreatic carcinogenesis.

Interplay between smoking-induced genotoxicity and altered signaling in pancreatic carcinogenesis

Despite continuous research efforts directed at early diagnosis and treatment of pancreatic cancer (PC), the status of patients affected by this deadly malignancy remains dismal. Its notoriety with regard to lack of early diagnosis and resistance to the current chemotherapeutics is due to accumulating signaling abnormalities. Hoarding experimental and epidemiological evidences have established a direct correlation between cigarette smoking and PC risk. The cancer initiating/promoting nature of cigarette smoke can be attributed to its various constituents including nicotine, which is the major psychoactive component, and several other toxic constituents, such as nitrosamines, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and polycyclic aromatic hydrocarbons. These predominant smoke-constituents initiate a series of oncogenic events facilitating epigenetic alterations, self-sufficiency in growth signals, evasion of apoptosis, sustained angiogenesis, and metastasis. A better understanding of the molecular mechanisms underpinning these events is crucial for the prevention and therapeutic intervention against PC. This review presents various interconnected signal transduction cascades, the smoking-mediated genotoxicity, and genetic polymorphisms influencing the susceptibility for smoking-mediated PC development by modulating pivotal biological aspects such as cell defense/tumor suppression, inflammation, DNA repair, as well as tobacco-carcinogen metabolization. Additionally, it provides a large perspective toward tumor biology and the therapeutic approaches against PC by targeting one or several steps of smoking-mediated signaling cascades.

The emerging role of smoking in the development of pancreatitis

BACKGROUND/AIMS

Cigarette smoking has been linked to many diseases, including pancreatic cancer and more recently, pancreatitis.

METHODS

Electronic searches of primarily PubMed from 1990 to August 2011 were conducted and only articles published in English were reviewed. Original articles and reviews were selected based on screening of article abstracts and their relevance to tobacco smoking, its components, nicotine and its metabolites, and their effects particularly on the pancreas.

RESULTS

Smoking may affect the risk of developing chronic pancreatitis or its progression. Smoking may also affect the risk for developing acute pancreatitis. Its effects in pancreatitis appear to be dose dependent and its effects may be alcohol independent but synergize with alcohol.

CONCLUSION

Specific constituents of cigarette smoke, including nicotine and its metabolites, could mediate effects on the pancreas.

Aldehyde dehydrogenase 3B1 (ALDH3B1): immunohistochemical tissue distribution and cellular-specific localization in normal and cancerous human tissues

Aldehyde dehydrogenase (ALDH) enzymes are critical in the detoxification of endogenous and exogenous aldehydes. Our previous findings indicate that the ALDH3B1 enzyme is expressed in several mouse tissues and is catalytically active toward aldehydes derived from lipid peroxidation, suggesting a potential role against oxidative stress. The aim of this study was to elucidate by immunohistochemistry the tissue, cellular, and subcellular distribution of ALDH3B1 in normal human tissues and in tumors of human lung, colon, breast, and ovary. Our results indicate that ALDH3B1 is expressed in a tissue-specific manner and in a limited number of cell types, including hepatocytes, proximal convoluted tubule cells, cerebellar astrocytes, bronchiole ciliated cells, testis efferent ductule ciliated cells, and histiocytes. ALDH3B1 expression was upregulated in a high percentage of human tumors (lung > breast = ovarian > colon). Increased ALDH3B1 expression in tumor cells may confer a growth advantage or be the result of an induction mechanism mediated by increased oxidative stress. Subcellular localization of ALDH3B1 was predominantly cytosolic in tissues, with the exception of normal human lung and testis, in which localization appeared membrane-bound or membrane-associated. The specificity of ALDH3B1 distribution may prove to be directly related to the functional role of this enzyme in human tissues.

Vitamin E reversed nicotine-induced toxic effects on bone biochemical markers in male rats

INTRODUCTION

Vitamin E is beneficial in restoring bone histomorphometric parameters in nicotine-treated rats. This study determined the effectiveness of 3 forms of vitamin E in restoring bone metabolism in nicotine-treated rats.

MATERIAL AND METHODS

Thirty-five male Sprague-Dawley rats were divided into 5 groups: (1) control (C), (2) nicotine cessation (NC), (3) α-tocopherol (ATF), (4) tocotrienol-enhanced fraction (TEF) and (5) γ-tocotrienol (GTT). Treatment was carried out for 4 months. The control group was administered normal saline and olive oil throughout the treatment period while treatment for groups 2-5 was performed in 2 phases. In the first phase, the groups received nicotine 7 mg/kg intraperitoneally for 2 months. The following 2 months, group 2 received normal saline and olive oil while groups 3-5 received ATF, TEF or GTT, 60 mg/kg orally. Pre-treatment and post-treatment serum was collected for bone biochemical marker measurement using the ELISA method.

RESULTS

Nicotine increased serum bone-resorbing cytokines (interleukin-1 and interleukin-6) and the bone resorption marker pyridinoline (PYD) while reducing the bone formation marker osteocalcin after 2 months of nicotine treatment. The parameters failed to improve after nicotine was stopped for 2 months. Supplementation with the 3 forms of vitamin E improved the parameters, i.e. reduced the cytokines and pyridinoline as well as increased the osteocalcin. In addition, the TEF and GTT groups had a higher level of osteocalcin than the control group.

CONCLUSIONS

Nicotine impaired bone metabolism and cessation of nicotine treatment did not reverse the effects. Vitamin E, especially the tocotrienols, restored bone metabolism that was impaired due to nicotine.