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

Passive smoking and risk of pancreatic cancer: an updated systematic review and meta-analysis

Background

Previous meta-analysis has demonstrated that no association was validated between passive smoking and pancreatic cancer. However, there is growing evidence on this issue recently. This study aimed to confirm this association.

Methods

PubMed, Embase, Web of Science, and Cochrane Library databases were searched up to April 2024 for retrieval of full articles. Studies with the exposure of passive smoking and outcome of pancreatic cancer were eligible for the analysis. We generated pooled relative risks (RRs) and 95% confidence intervals (CIs) using DerSimonian-Laird random-effects models. Quality of evidence was assessed using the GRADE system.

Results

Fourteen studies were included, with 5,560 pancreatic cancer patients. Passive smoking was associated with a moderate increased risk of pancreatic cancer (RR = 1.20, 95% CI: 1.11-1.30, p < 0.001). The results were consistent in both case-control (p=0.013) and cohort studies (p < 0.001) and in studies with high (p = 0.007) and moderate quality (p < 0.001). In subgroup analysis, the risk was significant for both current (RR=1.91, 95% CI: 1.45-2.51, p < 0.001) and non-current smokers (RR = 1.17, 95% CI: 1.01-1.36, p = 0.037), for exposure both in adulthood (RR = 1.18, 95% CI: 1.06-1.31, p = 0.002) and childhood (RR = 1.20, 95% CI: 1.08-1.34, p = 0.001). However, only regular or daily exposure (RR=1.28, 95% CI: 1.08-1.50, p = 0.003), rather than exposing occasionally, seldom or few times per week (p = 0.421), to passive smoking could increase the risk of pancreatic cancer.

Conclusion

Passive smoking exposure confers a significant increased risk for pancreatic cancer. The risk was valid in both case-control and cohort, high and moderate quality studies, in current and non-current smokers, and for both childhood and adulthood exposure. Regular or daily exposure rather than exposing occasionally, seldom or few times per week could exert a detrimental effect on pancreatic cancer.

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.

Multi-regulator of EZH2-PPARs Therapeutic Targets: A Hallmark for Prospective Restoration of Pancreatic Insulin Production and Cancer Dysregulation

The unexpected rise in cancer and diabetes statistics has been a significant global threat, inciting ongoing research into various biomarkers that can act as innovative therapeutic targets for their management. The recent discovery of how EZH2-PPARs' regulatory function affects the metabolic and signalling pathways contributing to this disease has posed a significant breakthrough, with the synergistic combination of inhibitors like GSK-126 and bezafibrate for treating these diseases. Nonetheless, no findings on other protein biomarkers involved in the associated side effects have been reported. As a result of this virtual study, we identified the gene-disease association, protein interaction networks between EZH2-PPARs and other protein biomarkers regulating pancreatic cancer and diabetes pathology, ADME/Toxicity profiling, docking simulation and density functional theory of some natural products. The results indicated a correlation between obesity and hypertensive disease for the investigated biomarkers. At the same time, the predicted protein network validates the link to cancer and diabetes, and nine natural products were screened to have versatile binding capacity against the targets. Among all natural products, phytocassane A outperforms the standard drugs' (GSK-126 and bezafibrate) in silico validation for drug-likeness profiles. Hence, these natural products were conclusively proposed for additional experimental screening to complement the results on their utility in drug development for diabetes and cancer therapy against the EZH2-PPARs' new target.

Environment factors, DNA methylation, and cancer

Today, the rapid development of science and technology and the rapid change in economy and society are changing the way of life of human beings and affecting the natural, living, working, and internal environment on which human beings depend. At the same time, the global incidence of cancer has increased significantly yearly, and cancer has become the number one killer that threatens human health. Studies have shown that diet, living habits, residential environment, mental and psychological factors, intestinal flora, genetics, social factors, and viral and non-viral infections are closely related to human cancer. However, the molecular mechanisms of the environment and cancer development remain to be further explored. In recent years, DNA methylation has become a key hub and bridge for environmental and cancer research. Some environmental factors can alter the hyper/hypomethylation of human cancer suppressor gene promoters, proto-oncogene promoters, and the whole genome, causing low/high expression or gene mutation of related genes, thereby exerting oncogenic or anticancer effects. It is expected to develop early warning markers of cancer environment based on DNA methylation, thereby providing new methods for early detection of cancers, diagnosis, and targeted therapy. This review systematically expounds on the internal mechanism of environmental factors affecting cancer by changing DNA methylation, aiming to help establish the concept of cancer prevention and improve people's health.

Pancreatic Cancer: Updates in Pathogenesis and Therapies

Despite the progress in pancreatic cancer (PC) chemo/radiotherapies, immunotherapies, and novel targeted therapies and the improvement in its peri-operative management policies, it still has a dismal catastrophic prognosis due to delayed detection, early neural and vascular invasions, early micro-metastatic spread, tumour heterogeneities, drug resistance either intrinsic or acquired, unique desmoplastic stroma, and tumour microenvironment (TME). Understanding tumour pathogenesis at the detailed genetic/epigenetic/metabolic/molecular levels as well as studying the tumour risk factors and its known precancerous lesions aggressively is required for getting a more successful therapy for this challenging tumour. For a better outcome of this catastrophic tumour, it should be diagnosed early and treated through multidisciplinary teams of surgeons, gastroenterologists/interventional upper endoscopists, medical/radiation oncologists, diagnostic/intervention radiologists, and pathologists at high-volume centres. Moreover, surgical resection with a negative margin (R0) is the only cure for it. In this chapter; we discuss the recently updated knowledge of PC pathogenesis, risk factors, and precancerous lesions as well as its different management tools (i.e. surgery, chemo/radiotherapies, immunotherapies, novel targeted therapies, local ablative therapies, etc.).

Diets, Dietary Patterns, Single Foods and Pancreatic Cancer Risk: An Umbrella Review of Meta-Analyses

Pancreatic cancer (PC) represents the third leading cause of cancer death in 2020. Despite the fact that, in 2018, the World Cancer Research Fund report concluded that there is still a lack of evidence on the role of foods or diets and risk for PC, a flourishing body of evidence has been published and needs to be analyzed. For this reason, we conducted an umbrella review on the association between different dietary patterns/food components and PC. Data sources PubMed/MEDLINE, Scopus, Web of Science, EMBASE, and the Cochrane Collaboration were searched. The Joanna Briggs Institute Umbrella Review Methodology was used. The protocol was registered in PROSPERO. A total of 23 articles were included, covering a wide range of dietary patterns/food components: healthy/prudent dietary patterns (n = 4), Mediterranean diets (MedDiet) (n = 1), plant-based diets (n = 2), the Dietary Inflammatory Index (DII) (n = 2), western diets (n = 2), and, lastly, unhealthy diets (n = 2). Regarding dietary components, the following were assessed: total fruit (n = 2), citrus fruit (n = 1), total vegetables (n = 2), cruciferous vegetables (n = 1), red meat (n = 6), processed meat (n = 4), poultry (n = 2), eggs (n = 1), fish (n = 5), whole grain (n = 2), potato (n = 1), and nuts (n = 2). The methodological quality of the included meta-analyses was generally low or critically low. Although the strength of evidence was generally weak, convincing or suggestive evidence was found for a healthy/prudent, plant-based diet, fruit and vegetables, and lower risk of PC, whereas a high intake of red meat was associated with a higher risk of PC at a convincing level of evidence. Further studies are needed to confirm the role of the other dietary patterns/food components and the risk of PC.

Pancreatic fibrosis by extracellular volume fraction using Contrast-enhanced computed tomography and relationship with pancreatic cancer

PURPOSE

This study aimed to assess the relationship between pancreatic fibrosis measured by the extracellular volume fraction (ECV) using contrast-enhanced computed tomography (CT) and the histologic pancreatic fibrosis fraction and investigate the relationship between pancreatic fibrosis and pancreatic cancer.

METHOD

The study included 88 consecutive patients (48 males, 40 females; median age, 69 years; range, 17-89 years); 47 had pancreatic cancer, and 41 had other diseases. Fifty-two cases were evaluated pathologically for pancreatic fibrosis. The histologic pancreatic fibrosis fraction was quantified using image analysis software in nontumorous pancreatic tissue at the resection stump using 2-µm-thick Azan-stained slides. Two board-certified radiologists measured ECV in the pancreatic parenchyma at an estimated transection line. The correlation between histologic pancreatic fibrosis fraction and ECV was investigated, and whether the ECV value could be used as a biomarker for pancreatic cancer was investigated.

RESULTS

The histologic pancreatic fibrosis fraction was significantly correlated with the ECV (r = 0.64, P < 0.01). Pancreatic fibrosis evaluated by ECV was higher in pancreatic cancer patients than in other patients (P < 0.01). On receiver-operating characteristic curve analysis, the ECV had good diagnostic accuracy for the development of pancreatic cancer (cut-off value 32.8%; sensitivity 61.0%, specificity 85.1%). ECV was identified on multivariate analysis as an independent risk factor for pancreatic cancer (odds ratio 1.16; P < 0.01).

CONCLUSIONS

Extracellular volume fraction was strongly related to the histologic pancreatic fibrosis fraction, which was independently associated with pancreatic cancer. Thus, extracellular volume fraction is an imaging biomarker that reflects the progression of pancreatic fibrosis and may potentially help predict the development of pancreatic cancer, although further investigation will be needed.

Pancreatic Adenocarcinoma: Trends in Epidemiology, Risk Factors, and Outcomes

Pancreatic cancer is one of the most lethal cancers in the world; it is a silent disease in which symptoms do not present until advanced stages, thereby reducing the 5-year survival rate to 10%. The global burden of pancreatic cancer has doubled over the past 25 years despite advancements in medicine. This review aims to discuss the global trends and disparities in pancreatic cancer, as well as the up-to-date literature on the known risk factors. A better understanding of these risk factors will reduce mortality by providing opportunities to screen these patients as well as counseling on lifestyle modifications.

Pancreatic Cancer: Pathogenesis, Screening, Diagnosis, and Treatment

Pancreatic ductal adenocarcinoma (PDAC) is a clinically challenging cancer, due to both its late stage at diagnosis and its resistance to chemotherapy. However, recent advances in our understanding of the biology of PDAC have revealed new opportunities for early detection and targeted therapy of PDAC. In this review, we discuss the pathogenesis of PDAC, including molecular alterations in tumor cells, cellular alterations in the tumor microenvironment, and population-level risk factors. We review the current status of surveillance and early detection of PDAC, including populations at high risk and screening approaches. We outline the diagnostic approach to PDAC and highlight key treatment considerations, including how therapeutic approaches change with disease stage and targetable subtypes of PDAC. Recent years have seen significant improvements in our approaches to detect and treat PDAC, but large-scale, coordinated efforts will be needed to maximize the clinical impact for patients and improve overall survival.

CBX3 Regulated By YBX1 Promotes Smoking-induced Pancreatic Cancer Progression via Inhibiting SMURF2 Expression

As a key reversible and heritable mechanism of transcriptional regulation, the epigenetic modification plays a crucial role in tumorigenesis. Of note, tobacco smoking induces epigenetic modifications to promote pancreatic cancer development. Chromobox protein homolog 3 (CBX3) acts as an epigenetic regulator, modulating gene expression of downstream targets via chromatin modifications. To date, the relationship between CBX3 and smoking in pancreatic cancer remains unknown. This study aimed to uncover the specific role and underlying mechanism of CBX3 in smoking-related pancreatic cancer. The bioinformatics analyses were conducted to identify CBX3 as a key player in tobacco-induced pancreatic cancer. The abnormal upregulation of CBX3 was associated with poor prognosis in pancreatic cancer patients. Moreover, cigarette smoke extract (CSE) exposure promoted the overexpression of Y-box-binding protein 1 (YBX1), which consequently led to upregulated CBX3 in pancreatic cancer cells. We also revealed that CBX3 enhanced pancreatic cancer progression, likely by inhibiting the expression of SMAD specific E3 ubiquitin protein ligase 2 (SMURF2) and promoting the activation of TGF-β signaling. In summary, the YBX1/CBX3/SMURF2 signaling axis may be a promising therapeutic target in patients with smoking-related pancreatic cancer.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone provokes progression from chronic pancreatitis to pancreatic intraepithelial neoplasia

The risk of pancreatic cancer is higher among people who are cigarette smokers than among non-smokers; however, the action mechanisms of cigarette metabolites are not yet fully understood. In this study, we investigated the effect of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in cigarette smoking on chronic pancreatitis and pancreatic cancer as well as the biological mechanism of NNK causing malignant transformation. We show that smoking may promote Kras mutation and P16 promoter methylation from clinical samples and NNK markedly facilitates the growth and migration of pancreatic cancer cells via the activation of Sonic Hedgehog signaling. We demonstrate that NNK promotes acinar-to-ductal metastasis and pancreatic intraepithelial neoplasia in rats with chronic pancreatitis, accompanied by desmoplastic reaction and Gli1 overexpression. Together, we here present evidence that NNK provokes the progression of chronic pancreatitis toward pancreatic cancer and highlight potential strategies and targets for early prevention of pancreatic cancer and its therapeutics.

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Smoking is positively correlated with Kras mutation and P16 hypermethylation

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NNK promotes acinar-to-ductal metastasis and preneoplasia lesions in rats

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NNK promotes desmoplastic reaction and Gli1 expression in chronic pancreatitis

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NNK facilitates the growth and migration of cancer via Sonic Hedgehog signaling

The Role of CDK4 in the Pathogenesis of Pancreatic Cancer

Pancreatic cancer (PC) continues to have the lowest overall survival and the lack of effective early diagnosis. Cyclin-dependent kinase 4 (CDK4) plays a fundamental role in the orderly progression of the cell cycle, binding to cyclin D to promote the progression through the G1/2 transition. The inhibition of CDK4/6 has therefore gained substantial interest in the hope of new and effective therapeutics in multiple cancers, such as advanced metastatic breast cancer. While the use of these agents is encouraging, their potential is yet to be fully explored. In this study we used the GLOBOCAN database to understand the most recent epidemiology of PC, Human Protein Atlas and KEGG to highlight the role, prevalence, and significance on patient survival of CDK4 in PC. We found that CDK4 cannot be used as prognostic in PC and no significant differences were observed between CDK4 expression and the patient's clinical status, though larger studies, especially concerning CDK4 protein expressions, are required for a more thorough understanding. The use of CDK4/6 inhibitors in PC is still in clinical trials. However, due to only modest improvements observed in the use of single-agent therapies, efforts have focused on combinatorial approaches.

Nuclear factor kappa-B contributes to cigarette smoke tolerance in pancreatic ductal adenocarcinoma through cysteine metabolism

BACKGROUND

Retrospective studies revealed that cigarette smoking enhances risk of incidence and worsens prognosis in pancreatic cancer (PC) patients. Poor prognosis in smoker cohort of PC patients indicates prevalence of cigarette smoke stimulated survival mechanisms yet to be explored in PC. In this study, cigarette smoke induced metabolic pathways were explored and targeted in PC.

METHODS

Human pancreatic ductal adenocarcinoma cell (PDAC) lines, genetically engineered mice models (GEMMs), mass spectrometry based heavy isotope-based metabolite analysis, cytotoxicity assays and Nuclear factor kappa-B (NF-kB) targeting were utilized in this study. Cigarette smoke extract (CSE) was prepared fresh each day by bubbling cell culture media with the smoke emitted from 85 mm, filtered, Code 1R6F reference cigarettes and used for in vitro procedures. High dose cigarette smoke exposure of GEMMs was achieved by daily exposure of animals to similar cigarettes, 6 h/day for a total period of 180 days.

FINDINGS

We observed that PDAC cells upregulate glutathione anabolism through cysteine uptake and glutamate cysteine ligase (GCLM), supporting survival, upon CSE exposure. In vivo, cigarette smoke exposure leads to concomitant upregulation of GCLM and activated NF-kB in the PDAC consistent with in vitro, in CSE-exposed PDAC. Finally, either inhibition of NF-kB or depletion of cysteine impaired PDAC cell survival in cigarette smoke exposed conditions through suppression of glutathione and ROS enhancement, reverted by glutathione supplementation.

INTERPRETATION

Our findings demonstrate scope for targeting smoke induced, NF-kB mediated, cysteine and glutathione metabolism for improving the survival of smoke addicted PDAC.

Nicotine promotes activation of human pancreatic stellate cells through inducing autophagy via α7nAChR-mediated JAK2/STAT3 signaling pathway

AIM

Pancreatic stellate cells (PSCs) are the main functional cells leading to pancreatic fibrosis. Nicotine is widely considered as an independent risk factor of pancreatic fibrosis, but the mechanism is still unclear. Our study was aimed to explore the effects of nicotine on human pancreatic stellate cells (hPSCs) and involved pathways.

MATERIALS AND METHODS

Primary human PSCs were cultured and treated with nicotine (0.1 μM and 1 μM). The proliferation, apoptosis, α-SMA expression, extracellular matrix metabolism and autophagy of hPSCs were detected by CCK-8 assay, flow cytometry, real-time PCR and Western blotting analysis. The α7nAChR-mediated JAK2/STAT3 signaling pathway was also examined, and an α7nAChR antagonist α-bungarotoxin (α-BTX) was used to perform inhibition experiments.

KEY FINDINGS

The proliferation, α-SMA expression and autophagy of hPSCs were significantly promoted by 1 μM nicotine. Meanwhile, the apoptosis of hPSCs was significantly reduced. The extracellular matrix metabolism of hPSCs was also regulated by nicotine. Moreover, the α7nAChR-mediated JAK2/STAT3 signaling pathway was activated by nicotine, this pathway and effects of nicotine can be blocked by α-BTX.

SIGNIFICANCE

Our finding suggests that nicotine can promote activation of human pancreatic stellate cells (hPSCs) through inducing autophagy via α7nAChR-mediated JAK2/STAT3 signaling pathway, providing a new insight into the mechanisms by which nicotine affects pancreatic fibrosis.

The Diverse Involvement of Cigarette Smoking in Pancreatic Cancer Development and Prognosis

Despite extensive research in the pathogenesis, early detection, and therapeutic approaches of pancreatic ductal adenocarcinoma (PDAC), it remains a devastating and incurable disease. As the global incidence and prevalence of PDAC continue to rise, there is a pressing need to place strong emphasis on its prevention. Although it is widely recognized that cigarette smoking, a potentially modifiable risk factor, has been linked to PDAC development, its contribution to prognosis is still uncertain. Moreover, the mechanistic pathways of PDAC progression secondary to smoking are various and lack a summative narration. Herein, we update and summarize the direct and indirect roles cigarette smoking plays on PDAC development, review literature to conclude the impact cigarette smoking has on prognosis, and postulate a comprehensive mechanism for cigarette smoking-induced PDAC.

Role of the microbiome in occurrence, development and treatment of pancreatic cancer

Pancreatic cancer is one of the most lethal malignancies. Recent studies indicated that development of pancreatic cancer may be intimately connected with the microbiome. In this review, we discuss the mechanisms through which microbiomes affect the development of pancreatic cancer, including inflammation and immunomodulation. Potential therapeutic and diagnostic applications of microbiomes are also discussed. For example, microbiomes may serve as diagnostic markers for pancreatic cancer, and may also play an important role in determining the efficacies of treatments such as chemo- and immunotherapies. Future studies will provide additional insights into the various roles of microbiomes in pancreatic cancer.

Pancreatic cancer associated with obesity and diabetes: an alternative approach for its targeting

BACKGROUND

Pancreatic cancer (PC) is among foremost causes of cancer related deaths worldwide due to generic symptoms, lack of effective screening strategies and resistance to chemo- and radiotherapies. The risk factors associated with PC include several metabolic disorders such as obesity, insulin resistance and type 2 diabetes mellitus (T2DM). Studies have shown that obesity and T2DM are associated with PC pathogenesis; however, their role in PC initiation and development remains obscure.

MAIN BODY

Several biochemical and physiological factors associated with obesity and/or T2DM including adipokines, inflammatory mediators, and altered microbiome are involved in PC progression and metastasis albeit by different molecular mechanisms. Deep understanding of these factors and causal relationship between factors and altered signaling pathways will facilitate deconvolution of disease complexity as well as lead to development of novel therapies. In the present review, we focuses on the interplay between adipocytokines, gut microbiota, adrenomedullin, hyaluronan, vanin and matrix metalloproteinase affected by metabolic alteration and pancreatic tumor progression.

CONCLUSIONS

Metabolic diseases, such as obesity and T2DM, contribute PC development through altered metabolic pathways. Delineating key players in oncogenic development in pancreas due to metabolic disorder could be a beneficial strategy to combat cancers associated with metabolic diseases in particular, PC.

Tobacco Carcinogen-Induced Production of GM-CSF Activates CREB to Promote Pancreatic Cancer

Although smoking is a significant risk factor for pancreatic ductal adenocarcinoma (PDAC), the molecular mechanisms underlying PDAC development and progression in smokers are still unclear. Here, we show the role of cyclic AMP response element-binding protein (CREB) in the pathogenesis of smoking-induced PDAC. Smokers had significantly higher levels of activated CREB when compared with nonsmokers. Cell lines derived from normal pancreas and pancreatic intraepithelial neoplasm (PanIN) exhibited low baseline pCREB levels compared with PDAC cell lines. Furthermore, elevated CREB expression correlated with reduced survival in patients with PDAC. Depletion of CREB significantly reduced tumor burden after tobacco-specific nitrosamine 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) treatment, suggesting a CREB-dependent contribution to PDAC growth and progression in smokers. Conversely, NNK accelerated PanIN lesion and PDAC formation via GM-CSF-mediated activation of CREB in a PDAC mouse model. CREB inhibition (CREBi) in mice more effectively reduced primary tumor burden compared with control or GM-CSF blockade alone following NNK exposure. GM-CSF played a role in the recruitment of tumor-associated macrophages (TAM) and regulatory T cell (Treg) expansion and promotion, whereas CREBi significantly reduced TAM and Treg populations in NNK-exposed mice. Overall, these results suggest that NNK exposure leads to activation of CREB through GM-CSF, promoting inflammatory and Akt pathways. Direct inhibition of CREB, but not GM-CSF, effectively abrogates these effects and inhibits tumor progression, offering a viable therapeutic strategy for patients with PDAC.Significance: These findings identify GM-CSF-induced CREB as a driver of pancreatic cancer in smokers and demonstrate the therapeutic potential of targeting CREB to reduce PDAC tumor growth.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/21/6146/F1.large.jpg Cancer Res; 78(21); 6146-58. ©2018 AACR.

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.

Resistin as a Prooxidant Factor and Predictor of Endothelium Damage in Patients with Mild Acute Pancreatitis Exposed to Tobacco Smoke Xenobiotics

Objectives

The study was aimed to assess the influence of tobacco smoke exposure on the intensity of inflammation measured by IL-6, α₁-antitripsin (AAT) and α₁-acid glycoprotein (AGP) concentrations, and Cd level and oxidative stress intensity measured by advanced oxidation protein product (AOPP) concentration in the blood of healthy subjects and AP patients during hospitalization. Endothelin-1 (ET-1) and resistin concentrations, markers of endothelium injury, were determined.

Results

An increased IL-6 concentration in healthy smokers compared to nonsmokers and AP patients compared to controls was shown. An increased AAT and AGP concentrations during hospitalization of AP patients were noted, in both smokers (AAT, AGP) and nonsmokers (AAT). In comparison to control groups, in AP patients, a 2-fold increased resistin concentration correlating with ET-1 concentration and decreased albumin concentration accompanied by increased AOPP concentration were demonstrated. AOPP concentration was higher in smokers with AP compared to nonsmokers and gradually enhanced during their hospitalization.

Conclusions

Tobacco smoke exposure can have a proinflammatory effect in both healthy subjects and AP patients. Increased resistin concentration in AP patients negatively correlating with albumin concentration has prooxidative effect on this protein resulting in enhanced AOPP level. Increased resistin concentration can intensify AAT and AGP production during AP.

Stiehopus japonieus acidic mucopolysaccharide inhibits the proliferation of pancreatic cancer SW1990 cells through Hippo-YAP pathway

Previous studies have indicated that stiehopus japonieus acidic mucopolysaccharide (SJAMP) could inhibit the proliferation of pancreatic cancer cell SW1990. However, the mechanism remains unclear. In our study, YAP expression was identified by immunohistochemistry and quantitative Real-time PCR from 45 pairs of human pancreatic ductal adenocarcinoma (PDAC) tissues and their adjacent non-tumor samples. We found that the YAP expression was associated with the histological differentiation degree, and negatively correlated with pancreatic cancer patients’ survival. More YAP localization in nuclear and enhanced expression of YAP mRNA in pancreatic cancer tissue was found in comparison with in the normal tissue. These results identify YAP acts as an amazing regulator in the pathogenesis of pancreatic cancer. After affected by SJAMP, YAP and TEAD1 were down regulated, while MST1 and pYAP were upregulated gradually with the prolong of effect time. SJAMP also improved YAP phosphorylation, nuclear-to-cytoplasmic translocation and inactivation. After successfully knocked-down by YAP siRNA, the inhibition of proliferation of SJAMP to cancer cells was attenuated. Interestingly, we indicated a down-regulation of that TEAD with SJAMP 4 mg/ml, 8 mg/ml for 24 h and with 8 mg/ml SJAMP for 24 h, 48 h even after YAP silencing. That might mean that the SJAMP has other targets, not only YAP, to downregulate TEAD. We proposed a hypothesis that Hippo-YAP pathway involved in carcinogenesis of pancreatic cancer and in the inhibition effect of SJAMP to the proliferation of pancreatic cancer cell, although maybe not the sole signaling pathway.

Smoking and IPMN malignant progression

BACKGROUND

Patients with intraductal papillary mucinous neoplasm (IPMN) are at risk for invasive pancreatic cancer. We aim to characterize the impact of smoking on IPMN malignant progression.

METHODS

Patients undergoing pancreatic resection for IPMN (1991-2015) were retrospectively reviewed using a prospectively collected database.

RESULTS

Of 422 patients identified, 324 had complete data for analysis; 55% were smokers. Smoking status did not impact IPMN malignant progression (smokers/non-smokers: 22%/18% invasive grade; p = 0.5). Smokers were younger than non-smokers at the time of IPMN diagnosis (63 versus 68 years; p = 0.001). This association also held in the invasive IPMN subgroup (65 versus 72 years, p = 0.01). Despite this observation, rate of symptoms at diagnosis, cancer stage, and median survival were the same between smokers and non-smokers.

CONCLUSION

Although smoking is not associated with IPMN malignant progression, invasive IPMN is diagnosed at a younger age in smokers. These data suggest tobacco exposure may accelerate IPMN malignant progression.

Genotoxicity testing of Persicariae Rhizoma (Persicaria tinctoria H. Gross) aqueous extracts

Persicariae Rhizoma (PR) has been used as an anti-inflammatory and detoxification agent in Korea, and contains the biologically active dyes purple indirubin and blue indigo. Despite synthetic indigo showing genotoxic potential, thorough studies have not been carried out on the genotoxicity of PR. The potential genotoxicity of an aqueous extract of PR containing indigo (0.043%) and indirubin (0.009%) was evaluated using a standard battery of tests for safety assessment. The PR extract did not induce any genotoxic effects under the conditions of this study. The results of a reverse mutation assay in four Salmonella typhimurium strains and one Escherichia coli strain indicated that PR extract did not increase the frequency of revertant colonies in any strain, regardless of whether S9 mix was present or not. The PR extract also did not increase chromosomal aberrations in the presence or absence of S9 mix. Although slight signs of diarrhea were restrictedly detected in the mice treated with 2,000 mg/kg PR extract, no noteworthy changes in the frequency of micronucleated polychromatic erythrocytes were observed at doses ≤2,000 mg/kg in a bone marrow micronucleus test. These results indicate the potential safety of the PR extract, particularly if it is consumed in small amounts compared with the quantities used in the genotoxicity tests.

Clinical, laboratory biomarkers and imaging findings of pancreatic adenocarcinoma in Iran

BACKGROUND

Pancreatic cancer has a high mortality rate because it is usually diagnosed late. Since little is known about this cancer in Iran, with the aim of improving this knowledge deficiency, we evaluated clinical, laboratory biomarkers, imaging findings and treatment modalities in Iranian patients with pancreatic adenocarcinoma.

MATERIALS AND METHODS

131 cases of pancreatic adenocarcinoma in 2010-2013 were obtained from the Taleghani Hospital Record Department. Cases confirmed by histopathology from CT-guided biopsy, EUS-FNA and surgery examination were included. We excluded those with incomplete medical records.

RESULTS

The study included 131 subjects between 24 and 97 years of age and a mean age of 63 ± 13.4 years. Eighty (61.1%) were male and 51 (38.9%) female. Previous history included diabetes mellitus in 36 (27.5%), alcohol drinking in 5 (3.9%), smoker in 28 (21.4%) and opium addiction in 13 (10%) . The common presenting history included weight loss in 79 (60.3%), abdominal pain in 77 (58.8%), fever in 11 (8.4%), nausea in 30 (22.9%), jaundice in 72 (55%), pruritus in 52 (39.7) and anemia in 33 (25.2%) . CA19-9 levels with cut offs of 50, 100 and 200 U/ml were increased in 81%, 72% and 66% of patients, respectively. Tumor staging was: stage I, 3 (2.3%); stage II, 10 (7.6%); stage III, 58 (44.3%); and stage IV, 60 (45.8%). From 45 patients, 17 received ERCP inserted metallic stents and 22 plastic stents, the remaining 6 failed that PTC was done. Whipple surgery and chemotherapy were conducted for 10 and 29 patients, respectively.

CONCLUSIONS

This disease affected older people and there was a male preponderance. The commonest risk factors were diabetes mellitus, smoking and cholelithiasis. The majority of patients presented with loss of appetite, loss of weight, jaundice, abdominal pain and discomfort. Almost all presented at late stages of the disease so that curative surgery was impossible. Also chemotherapy was only performed in a few patients as a neoadjuant treatment.

Synergistic protective effect of folic acid and vitamin B12 against nicotine-induced oxidative stress and apoptosis in pancreatic islets of the rat

CONTEXT

Nicotine is an abundant and most significant component of cigarette smoke. Epidemiological evidence strongly suggests an association between cigarette smoking and pancreatic injury, although effects of smoking on endocrine pancreas are still controversial.

OBJECTIVE

We examined the impact and underlying mechanisms of action of folic acid and vitamin B12 on nicotine-induced damage in pancreatic islets of rats.

MATERIALS AND METHODS

Male Wistar rats were treated with nicotine (3 mg/kg body weight/d, intraperitonealy) with or without folic acid (36 µg/kg body weight/d, orally) and vitamin B12 (0.63 µg/kg body weight/d, orally) for 21 d. Fasting blood glucose, oral glucose tolerance test, HBA1c, insulin, oxidative stress parameters, proinflammatory cytokines, and CRP level were measured. Histological evaluation, TUNEL assay, and immunohistochemical staining of NF-κB and caspase-3 were also performed.

RESULTS

Folic acid and vitamin B12 blunted the nicotine-induced impairment in fasting blood glucose (51-56% recovery), HbA1c (64-76% recovery), oral glucose tolerance, insulin level (23-40% recovery), and islet cell counts (26-74% recovery) in rats. Moreover, folic acid in combination with vitamin B12 also attenuated the nicotine-induced changes in markers of oxidative stress (17-88% recovery), TNF-α (40-99% recovery), and IL-6 level (47-65% recovery), CRP level (59-73% recovery), expression of NF-κB and caspase-3, and apoptosis in pancreatic islet cells.

DISCUSSION AND CONCLUSION

The present study shows that folic acid and vitamin B12 supplementation can reduce nicotine-induced impairment in glucose homeostasis and apoptosis and damage of pancreatic islet cells by modulating oxidative stress, levels of proinflammatory cytokines, and expression of NF-κB.

Germline copy number variation in the YTHDC2 gene: does it have a role in finding a novel potential molecular target involved in pancreatic adenocarcinoma susceptibility?

OBJECTIVE

The vast majority of pancreatic cancers occurs sporadically. The discovery of frequent variations in germline gene copy number can significantly influence the expression levels of genes that predispose to pancreatic adenocarcinoma. We prospectively investigated whether patients with sporadic pancreatic adenocarcinoma share specific gene copy number variations (CNVs) in their germline DNA.

PATIENTS AND METHODS

DNA samples were analyzed from peripheral leukocytes from 72 patients with a diagnosis of sporadic pancreatic adenocarcinoma and from 60 controls using Affymetrix 500K array set. Multiplex ligation-dependent probe amplification (MLPA) assay was performed using a set of self-designed MLPA probes specific for seven target sequences.

RESULTS

We identified a CNV-containing DNA region associated with pancreatic cancer risk. This region shows a deletion of 1 allele in 36 of the 72 analyzed patients but in none of the controls. This region is of particular interest since it contains the YTHDC2 gene encoding for a putative DNA/RNA helicase, such protein being frequently involved in cancer susceptibility. Interestingly, 82.6% of Sicilian patients showed germline loss of one allele.

CONCLUSIONS

Our results suggest that the YTHDC2 gene could be a potential candidate for pancreatic cancer susceptibility and a useful marker for early detection as well as for the development of possible new therapeutic strategies.

Src as the link between inflammation and cancer

Although a causal link between chronic inflammation and cancer has been established, the exact molecular mechanism linking inflammation to cancer remains largely unknown. It was previously postulated that molecular switches responsible for cancer cell development, and for infiltration of inflammatory cells into cancer, were divided into a distinct set of intracellular proteins and signaling pathways. However, recent evidence suggests that both tumor cells and tumor-infiltrating immune cells utilize the same kinases, mostly that of Src family, to facilitate cancer development and progression. In the past few years several groups have found that Src activation both in cancer and inflammatory cells is mainly driven by pro-inflammatory cytokines within the tumor microenvironment. Here we evaluate the cross talks between Src kinase pathways in immune cells and cancer cells. We conclude that Src might serve as a critical mechanistic link between inflammation and cancer, mediating and propagating a cycle between immune and tissue cells that can ultimately lead to the development and progression of cancer.

Incidence and trends of malignant and benign pancreatic lesions in Yazd, Iran between 2001 and 2011

BACKGROUND

Despite recent valuable steps in initiating a cancer registry in Iran, data depicting prevalence, incidence, and clinical picture of pancreatic tumors in the country are exceedinglyly sparse. With the aim of filling this knowledge gap, we reviewed cases in the pathology archive of Shahid Sadoughi hospital (Yazd, Iran), between 2001 and 2011.

MATERIALS AND METHODS

Medical records of 177 patients are reported in the present study. In cases for which paraffin-embedded blocks were available, the specimens were evaluated by two independent pathologists blinded to the primary diagnosis. We extrapolated the frequency of malignant lesions in our study to the population of Yazd province, derived from national census data, to generate cancer incidence rates.

RESULTS

Final diagnosis of malignancy was made in 117 cases (66.1%), and the remainder (60 lesions, 33.9%) were classified as benign. Adenecarcinoma and neuroendocrine tumors were the two most common histological types of malignancy identified in 88 (75.2%) and 11 (9.4%) specimens, respectively. Crude annual incidence of pancreatic cancer was 0.55 per 100,000 person in 2001 and increased to 1.68 in 2011. Age standardized incidence rates in 2001 and 2011 were 0.75 and 2.68, respectively. A significant increasing trend in cancer incidence was observed during the 11 years of the study period (r =+0.856, p=0.009). Sex-stratified analysis, confirmed the observed trend in men (r=+0.728, p=0.034), but not women (r=+0.635, p=0.083).

CONCLUSIONS

Over the past decade, incidence of pancreas malignancies has risen steadily in Yazd, Iran. Nevertheless, these figures are still substantially lower than those prevalent in developed nations.

Active and passive smoking and risk of death from pancreatic cancer: findings from the Japan Collaborative Cohort Study

BACKGROUND

There is uncertainty in the risk of pancreatic cancer with particular aspects of smoking, such as a dose-response relationship and cumulative amount, in Japanese men and women. Very few studies have addressed the role of passive smoking in pancreatic cancer among Japanese women.

METHODS

We examined the association between active or passive smoking and the risk of death from pancreatic cancer using data from the Japan Collaborative Cohort Study. The cohort participants (46,395 men and 64,190 women) were followed-up for mortality from baseline (1988-1990) through December 31, 2009. Cox proportional hazards regression models were used to estimate relative risks (RR) and 95% confidence intervals (CI).

RESULTS

During follow-up, we recorded 611 pancreatic cancer deaths. After adjustment for potential confounding factors, current smokers had a significantly increased risk of death from pancreatic cancer compared with non-smokers, with an RR of 1.70 (95% CI: 1.33-2.19). The risk of death from pancreatic cancer significantly increased with increasing numbers of cigarettes smoked per day. Exposure to environmental tobacco smoke (ETS) in public spaces was not associated with risk of death from pancreatic cancer. The RR for women who reported ETS exposure was 1.20 (95% CI: 0.87-1.67). Women exposed to ETS during childhood or adolescence had 1.21-fold increased risk, but the association was statistically insignificant.

CONCLUSIONS

Cigarette smoking is associated with an approximately 70% increase in the risk of death from pancreatic cancer. Further studies with improved exposure assessment are needed to better quantify the association between passive smoking and pancreatic cancer.

Insertion/deletion polymorphisms in the promoter region of BRM contribute to risk of hepatocellular carcinoma in Chinese populations

BACKGROUND

BRM (Brahma homologue) is well known for its critical role in tumor suppression and cancer development. Genetic variations in the promoter region of BRM have been suggested to be associated with loss of BRM expression and lung cancer risk. To the authors' knowledge, no study on the role of BRM genetic polymorphisms in hepatocellular carcinoma (HCC) risk has been performed.

METHODOLOGY/PRINCIPAL FINDINGS

In two independent case-control studies containing 796 HCC cases and 806 cancer-free individuals, we genotyped two putative functional insertion/deletion (indel) polymorphisms [BRM-1321 (rs3832613) and BRM-741 (rs34480940)] within promoter region of BRM in Chinese populations using a PCR-based method. Real-time RT-PCR analysis was used to explore the genotype-phenotype correlation between these polymorphisms and BRM expression in both tissue samples and HCC cell lines. Logistic regression analysis showed that compared to BRM-1321del/del genotype, the ins/del and ins/ins variant genotypes had an increased HCC risk [adjusted odds ratio (OR) = 1.47, 95% confidence interval (CI) = 1.19-1.82; adjusted OR = 2.55, 95% CI = 1.75-3.72, respectively]. No significant association between BRM-741 and HCC incidence was observed. However, stratification analysis revealed a significant association between ins/ins genotype of BRM-741 and increased HCC susceptibility in smokers (adjusted OR = 2.07, 95% CI = 1.33-3.22). Quantitative PCR analyses demonstrated that the genotypes of BRM-1321 and the corresponding haplotypes were significantly correlated with BRM expression in vivo. Compared with ins/ins genotype, subjects carrying ins/del and del/del genotype had 2.30 and 4.99 fold higher BRM expression in HCC tissue samples, respectively. Similar trends were observed in western blot analysis at protein level.

CONCLUSIONS/SIGNIFICANCE

Our findings suggest that BRM promoter polymorphism (BRM-1321) could regulate BRM expression and may serve as a potential marker for genetic susceptibility to HCC.

Discovering the route from inflammation to pancreatic cancer

Pancreatic cancer (PC) remains a complex malignancy with the worst prognosis, lack of early diagnostic symptoms and resistance to conventional chemo- and radiotherapies. A better understanding of the etiology and early developmental events of PC requires profound attention. The evolution of fully blown PC from initial pancreatic injury is a multi-factorial phenomenon with a series of sequential events. The initial acute infection or tissue damage triggers inflammation that, in conjunction with innate immunity, establishes a state of homeostasis to limit harm to the body. Recurrent pancreatic injuries due to genetic susceptibility, smoking, unhealthy diet, and alcohol abuse induces a pro-inflammatory milieu, consisting of various types of immune cells, cytokines, chemokines, growth factors and restructured extracellular matrix, leading to prolonged inflammatory/chronic conditions. Cells having sustained DNA damage and/or mutagenic assault take advantage of this prolonged inflammatory response and aid in the initiation and development of neoplastic/fibrotic events. Eventually, many tumor-stromal interactions result in a chaotic environment accompanied by a loss of immune surveillance and repair response, thereby leading to PC. A better understanding of the inflammatory markers defining this "injury-inflammation-cancer" pathway would help to identify novel molecular targets for early screening and therapeutic intervention for this lethal malignancy.