Myeloperoxidase and superoxide dismutase polymorphisms are associated with an increased risk of developing pancreatic adenocarcinoma

The Role of Chemokines in Orchestrating the Immune Response to Pancreatic Ductal Adenocarcinoma

Chemokines are small molecules that function as chemotactic factors which regulate the migration, infiltration, and accumulation of immune cells. Here, we comprehensively assess the structural and functional role of chemokines, examine the effects of chemokines that are present in the pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment (TME), specifically those produced by cancer cells and stromal components, and evaluate their impact on immune cell trafficking, both in promoting and suppressing anti-tumor responses. We further explore the impact of chemokines on patient outcomes in PDAC and their role in the context of immunotherapy treatments, and review clinical trials that have targeted chemokine receptors and ligands in the treatment of PDAC. Lastly, we highlight potential strategies that can be utilized to harness chemokines in order to increase cytotoxic immune cell infiltration and the anti-tumor effects of immunotherapy.

Monomeric myeloperoxidase is a specific biomarker for early-stage ovarian cancer

Background: Ovarian cancer cells are known to express myeloperoxidase (MPO), an oxidant-producing enzyme with a 150 kDa homodimer, consisting of two identical monomers connected by a disulfide bond. Here, we aim to validate monomeric MPO (mMPO) as a biomarker for the early detection of ovarian cancer.Methods: Human ovarian cancer cells, sera from patients at various stages, sera from non-cancer inflammatory gynecological diseases, and healthy volunteers were used. Monomeric and dimeric MPO were measured by ELISA. Receiver operating curves were used to compare the predictive powers of serum dimeric and monomeric MPO to discriminate between samples.Results: The expression of MPO was unique to ovarian cancer cells. Specifically, mMPO was found to be the only form of MPO in all ovarian cancer cell lines. Intriguingly, mMPO was detected in the sera from all patients with ovarian cancer at various stages, but not from healthy individuals. Serum mMPO discriminated between early-stage ovarian cancer, healthy controls, and benign inflammatory gynecologic disorders. In addition, mMPO discriminated between the early and late stages of the disease.Conclusion: This work highlights mMPO as a potential biomarker for early detection of ovarian cancer, which is critically needed.

Myeloperoxidase: Regulation of Neutrophil Function and Target for Therapy

Neutrophils, the most abundant white blood cells in humans, are critical for host defense against invading pathogens. Equipped with an array of antimicrobial molecules, neutrophils can eradicate bacteria and clear debris. Among the microbicide proteins is the heme protein myeloperoxidase (MPO), stored in the azurophilic granules, and catalyzes the formation of the chlorinating oxidant HOCl and other oxidants (HOSCN and HOBr). MPO is generally associated with killing trapped bacteria and inflicting collateral tissue damage to the host. However, the characterization of non-enzymatic functions of MPO suggests additional roles for this protein. Indeed, evolving evidence indicates that MPO can directly modulate the function and fate of neutrophils, thereby shaping immunity. These actions include MPO orchestration of neutrophil trafficking, activation, phagocytosis, lifespan, formation of extracellular traps, and MPO-triggered autoimmunity. This review scrutinizes the multifaceted roles of MPO in immunity, focusing on neutrophil-mediated host defense, tissue damage, repair, and autoimmunity. We also discuss novel therapeutic approaches to target MPO activity, expression, or MPO signaling for the treatment of inflammatory and autoimmune diseases.

Recent advances in the application of metallomics in diagnosis and prognosis of human cancer

Metals play a critical role in human health and diseases. In recent years, metallomics has been introduced and extensively applied to investigate the distribution, regulation, function, and crosstalk of metal(loid) ions in various physiological and pathological processes. Based on high-throughput multielemental analytical techniques and bioinformatics methods, it is possible to elucidate the correlation between the metabolism and homeostasis of diverse metals and complex diseases, in particular for cancer. This review aims to provide an overview of recent progress made in the application of metallomics in cancer research. We mainly focuses on the studies about metallomic profiling of different human biological samples for several major types of cancer, which reveal distinct and dynamic patterns of metal ion contents and the potential benefits of using such information in the detection and prognosis of these malignancies. Elevated levels of copper appear to be a significant risk factor for various cancers, and each type of cancer has a unique distribution of metals in biofluids, hair/nails, and tumor-affected tissues. Furthermore, associations between genetic variations in representative metalloprotein genes and cancer susceptibility have also been demonstrated. Overall, metallomics not only offers a better understanding of the relationship between metal dyshomeostasis and the development of cancer but also facilitates the discovery of new diagnostic and prognostic markers for cancer translational medicine.

The relationship between night shift work and breast cancer incidence: A systematic review and meta-analysis of observational studies

The purpose of this study was to investigate the relationship between night shift work and breast cancer (BC) incidence. A search was performed in PubMed, EBSCO, Web of Science, and Cochrane Library databases before June 2021. The exposure factor of this study is night shift work, the primary outcome is the risk of BC. A total of 33 observational studies composed of 4,331,782 participants were included. Night shift work increases the risk of BC in the female population (hazard ratio [HR] = 1.20, 95% confidence interval [Cl] = 1.10–1.31, p < 0.001), especially receptor-positive BC, including estrogen receptor (ER)+ BC (HR = 1.35, p < 0.001), progesterone receptor (PR)+ BC (HR = 1.30, p = 0.003), and human epidermal growth factor receptor 2 (HER2)+ BC (HR = 1.42, p < 0.001), but has no effect on HER2− BC (HR = 1.10, p = 0.515) and ER−/PR− BC (HR = 0.98, p = 0.827). The risk of BC was positively correlated with night shift working duration, frequency, and cumulative times. For women who start night work before menopause, night work will increase the incidence of BC (HR = 1.17, p = 0.020), but for women who start night work after menopause, night work does not affect BC (HR = 1.04, p = 0.293). Night work can increase the incidence of BC in the female population. The effect of long working hours, frequency, and the cumulative number of night shifts on BC is influenced by menopausal status.

Myeloperoxidase exerts anti-tumor activity in glioma after radiotherapy

Background

Host immune response is a critical component in tumorigenesis and immune escape. Radiation is widely used for glioblastoma (GBM) and can induce marked tissue inflammation and substantially alter host immune response. However, the role of myeloperoxidase (MPO), a key enzyme in inflammation and host immune response, in tumorigenesis after radiotherapy is unclear. In this study, we aimed to determine how post-radiation MPO activity influences GBM and outcome.

Methods

We injected C57BL/6J or MPO-knockout mice with 005 mouse GBM stem cells intracranially. To observe MPO's effects on post-radiation tumor progression, we then irradiated the head with 10 Gy unfractionated and treated the mice with a specific MPO inhibitor, 4-aminobenzoic acid hydrazide (ABAH), or vehicle as control. We performed semi-quantitative longitudinal molecular MRI, enzymatic assays and flow cytometry to assess changes in inflammatory response and tumor size, and tracked survival. We also performed cell culture experiments in murine and human GBM cells to determine the effect of MPO on these cells.

Results

Brain irradiation increased the number of monocytes/macrophages and neutrophils, and boosted MPO activity by ten-fold in the glioma microenvironment. However, MPO inhibition dampened radiation-induced inflammation, demonstrating decreased MPO-specific signal on molecular MRI and attenuated neutrophil and inflammatory monocyte/macrophage recruitment to the glioma. Compared to saline-treated mice, both ABAH-treated and MPO-knockout mice had accelerated tumor growth and reduced survival. We further confirmed that MPO decreased tumor cell viability and proliferation in cell cultures.

Conclusion

Local radiation to the brain initiated an acute systemic inflammatory response with increased MPO-carrying cells both in the periphery and the GBM, resulting in increased MPO activity in the tumor microenvironment. Inhibition or absence of MPO activity increased tumor growth and decreased host survival, revealing that elevated MPO activity after radiation has an anti-tumor role.

SOD2, a Potential Transcriptional Target Underpinning CD44-Promoted Breast Cancer Progression

CD44, a cell-adhesion molecule has a dual role in tumor growth and progression; it acts as a tumor suppressor as well as a tumor promoter. In our previous work, we developed a tetracycline-off regulated expression of CD44's gene in the breast cancer (BC) cell line MCF-7 (B5 clone). Using cDNA oligo gene expression microarray, we identified SOD2 (superoxide dismutase 2) as a potential CD44-downstream transcriptional target involved in BC metastasis. SOD2 gene belongs to the family of iron/manganese superoxide dismutase family and encodes a mitochondrial protein. SOD2 plays a role in cell proliferation and cell invasion via activation of different signaling pathways regulating angiogenic abilities of breast tumor cells. This review will focus on the findings supporting the underlying mechanisms associated with the oncogenic potential of SOD2 in the onset and progression of cancer, especially in BC and the potential clinical relevance of its various inhibitors.

Molecular immuno-imaging improves tumor detection in head and neck cancer

Detection and accurate delineation of tumor is important for the management of head and neck squamous cell carcinoma (HNSCC) but is challenging with current imaging techniques. In this study, we evaluated whether molecular immuno-imaging targeting myeloperoxidase (MPO) activity, an oxidative enzyme secreted by many myeloid innate immune cells, would be superior in detecting tumor extent compared to conventional contrast agent (DTPA-Gd) in a carcinogen-induced immunocompetent HNSCC murine model and corroborated in human surgical specimens. In C57BL/6 mice given 4-nitroquinoline-N-oxide (4-NQO), there was increased MPO activity in the head and neck region as detected by luminol bioluminescence compared to that of the control group. On magnetic resonance imaging, the mean enhancing volume detected by the MPO-targeting agent (MPO-Gd) was higher than that by the conventional agent DTPA-Gd. The tumor volume detected by MPO-Gd strongly correlated with tumor size on histology, and higher MPO-Gd signal corresponded to larger tumor size found by imaging and histology. On the contrary, the tumor volume detected by DTPA-Gd did not correlate as well with tumor size on histology. Importantly, MPO-Gd imaging detected areas not visualized with DTPA-Gd imaging that were confirmed histopathologically to represent early tumor. In human specimens, MPO was similarly associated with tumors, especially at the tumor margins. Thus, molecular immuno-imaging targeting MPO not only detects oxidative immune response in HNSCC, but can better detect and delineate tumor extent than nonselective imaging agents. Thus, our findings revealed that MPO imaging could improve tumor resection as well as be a useful imaging biomarker for tumor progression, and potentially improve clinical management of HNSCC once translated.

Neutrophil-derived granule cargoes: paving the way for tumor growth and progression

Neutrophils are the key cells of our innate immune system mediating host defense via a range of effector functions including phagocytosis, degranulation, and NETosis. For this, they employ an arsenal of anti-microbial cargoes packed in their readily mobilizable granule subsets. Notably, the release of granule content is tightly regulated; however, under certain circumstances, their unregulated release can aggravate tissue damage and could be detrimental to the host. Several constituents of neutrophil granules have also been associated with various inflammatory diseases including cancer. In cancer setting, their excessive release may modulate tissue microenvironment which ultimately leads the way for tumor initiation, growth and metastasis. Neutrophils actively infiltrate within tumor tissues, wherein they show diverse phenotypic and functional heterogeneity. While most studies are focused at understanding the phenotypic heterogeneity of neutrophils, their functional heterogeneity, much of which is likely orchestrated by their granule cargoes, is beginning to emerge. Therefore, a better understanding of neutrophil granules and their cargoes will not only shed light on their diverse role in cancer but will also reveal them as novel therapeutic targets. This review provides an overview on existing knowledge of neutrophil granules and detailed insight into the pathological relevance of their cargoes in cancer. In addition, we also discuss the therapeutic approach for targeting neutrophils or their microenvironment in disease setting that will pave the way forward for future research.

Riding the tiger - physiological and pathological effects of superoxide and hydrogen peroxide generated in the mitochondrial matrix

Elevated mitochondrial matrix superoxide and/or hydrogen peroxide concentrations drive a wide range of physiological responses and pathologies. Concentrations of superoxide and hydrogen peroxide in the mitochondrial matrix are set mainly by rates of production, the activities of superoxide dismutase-2 (SOD2) and peroxiredoxin-3 (PRDX3), and by diffusion of hydrogen peroxide to the cytosol. These considerations can be used to generate criteria for assessing whether changes in matrix superoxide or hydrogen peroxide are both necessary and sufficient to drive redox signaling and pathology: is a phenotype affected by suppressing superoxide and hydrogen peroxide production; by manipulating the levels of SOD2, PRDX3 or mitochondria-targeted catalase; and by adding mitochondria-targeted SOD/catalase mimetics or mitochondria-targeted antioxidants? Is the pathology associated with variants in SOD2 and PRDX3 genes? Filtering the large literature on mitochondrial redox signaling using these criteria highlights considerable evidence that mitochondrial superoxide and hydrogen peroxide drive physiological responses involved in cellular stress management, including apoptosis, autophagy, propagation of endoplasmic reticulum stress, cellular senescence, HIF1α signaling, and immune responses. They also affect cell proliferation, migration, differentiation, and the cell cycle. Filtering the huge literature on pathologies highlights strong experimental evidence that 30-40 pathologies may be driven by mitochondrial matrix superoxide or hydrogen peroxide. These can be grouped into overlapping and interacting categories: metabolic, cardiovascular, inflammatory, and neurological diseases; cancer; ischemia/reperfusion injury; aging and its diseases; external insults, and genetic diseases. Understanding the involvement of mitochondrial matrix superoxide and hydrogen peroxide concentrations in these diseases can facilitate the rational development of appropriate therapies.

Myeloperoxidase-mediated oxidation of edaravone produces an apparent non-toxic free radical metabolite and modulates hydrogen peroxide-mediated cytotoxicity in HL-60 cells

Edaravone is considered to be a potent antioxidant drug known to scavenge free radical species and prevent free radical-induced lipid peroxidation. In this study, we investigated the effect of edaravone on the myeloperoxidase (MPO) activity, an enzyme responsible for the production of an array of neutrophil-derived oxidants that can cause cellular damage. The addition of edaravone to the reaction of MPO and hydrogen peroxide (H₂O₂) significantly enhanced the reduction of MPO Compound II back to native MPO. Interestingly, the MPO-mediated production of toxic hypochlorous acid exhibited a concentration-dependent biphasic effect, with the apparent optimal edaravone concentration at 10 μM. Oxidation of edaravone by MPO was examined by various analytical methods. An MPO-catalyzed product(s) of edaravone was identified at 350 nm by kinetic analysis of UV-Vis spectroscopy. Several MPO-catalyzed metabolites of edaravone were proposed from the LC-MS analyses, including oxidized dimers from edaravone radicals. Electron spin resonance (ESR) spin trapping detected a carbon-centred radical metabolite of edaravone. NMR studies revealed that there are two exchangeable hydrogens, one of which is on the α-carbon, justifying the carbon-centred edaravone radical produced from MPO. Despite the formation of an edaravone carbon-radical metabolite, it did not appear to effectively oxidize GSH (in comparison with phenoxyl radicals). Viability (ATP) and cytotoxicity (LDH release) assays showed a concentration-dependent effect of edaravone on HL-60 cells treated with either a bolus concentration of 30 μM H₂O₂ or a flux of H₂O₂ generated by 5 mM glucose and 10 mU/mL glucose oxidase. The H₂O₂-induced toxicity was ameliorated at high edaravone concentrations (100-200 μM). In contrast, low concentrations of edaravone (1-10 μM) exacerbated the H₂O₂-induced toxicity. However, the effect of edaravone at low concentration (0-10 μM) appeared more prominent with the LDH assay only. The cellular findings correlated with the biochemical studies with respect to hypochlorous acid formation. These findings provide interesting perspectives regarding the duality of edaravone as an antioxidant drug.

Evaluation of cancer risk in patients with periodontal diseases

BACKGROUND/AIM

In this study, we aimed to assess the cancer risk among patients with periodontal disease.

MATERIALS AND METHODS

Patients diagnosed with periodontal diseases at Hacettepe University between 2007 and 2012 were included and data on the diagnosis of any cancer after periodontal disease were collected from patient files. The age- and sex-standardized incidence rates (SIRs) were calculated using Turkish National Cancer Registry 2013 data.

RESULTS

A total of 5199 patients were included. Median follow-up was 7.2 years. Patients with periodontal diseases had 17% increased risk of cancer compared with the expected counts for the corresponding age and sex groups (SIR: 1.17; 95% CI: 1.04–1.3, P = 0.006). The increased cancer risk was statistically significant in women (SIR: 1.24; 95% CI: 1.05–1.45, P = 0.008) but not in men. Among women with periodontal disease, the risks of breast cancer (SIR: 2.19) and head and neck cancer (SIR: 4.71) were significantly increased. Among men, the risks of prostate cancer (SIR: 1.84), head and neck cancer (SIR: 3.55), and hematological cancers (SIR: 1.76) were significantly increased.

CONCLUSION

This study showed that periodontal diseases were associated with increased risk of several cancers. Besides other well-known benefits for health, the provision of oral/dental health should be considered and employed as a cancer prevention measure.

Association between MnSOD Val16Ala Polymorphism and Cancer Risk: Evidence from 33,098 Cases and 37,831 Controls

Manganese superoxide dismutase (MnSOD) plays a critical role in the defense against reactive oxygen species. The association between MnSOD Val16Ala polymorphism and cancer risk has been widely studied, but the results are contradictory. To obtain more precision on the association, we performed the current meta-analysis with 33,098 cases and 37,831 controls from 88 studies retrieved from PubMed, Embase, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of association. We found that the polymorphism was associated with an increased overall cancer risk (homozygous: OR = 1.09, 95% CI = 1.00-1.19; heterozygous: OR = 1.07, 95% CI = 1.02-1.12; dominant: OR = 1.08, 95% CI = 1.02-1.14; and allele comparison: OR = 1.06, 95% CI = 1.02-1.11). Stratification analysis further showed an increased risk for prostate cancer, Asians, Caucasians, population-based studies, hospital-based studies, low quality and high quality studies. However, the increased risk for MnSOD Val16Ala polymorphism among Asians needs further validation based on the false-positive report probability (FPRP) test. To summarize, this meta-analysis suggests that the MnSOD Val16Ala polymorphism is associated with significantly increased cancer risk, which needs further validation in single large studies.

Oral Health of Korean Patients With Head and Neck Cancer

Background

Association between periodontitis and of head and neck carcinoma was suggested. In the present study, we evaluated the oral health status of patients with head and neck carcinoma and analyzed the relationship between cancer characteristics and oral health.

Methods

Oral health of 40 patients with head and neck carcinoma was examined. Decayed teeth, missing teeth, plaque index, gingival index, and probing depth were measured. Cancer type and site were recorded based on the patients' medical records.

Results

The average age of participants was 60.10 ± 8.99 years, and 35 of participants were male. The decay or missing teeth index was 5.43 ± 5.57, and the plaque index, gingival index, and probing depth were 1.37 ± 1.03, 1.57 ± 0.84, and 4.13 ± 1.45, respectively. These indexes showed no significant difference according to the type or site of cancer (P > 0.05).

Conclusions

This study showed that there was no correlation between oral health parameters and characteristics of head and neck carcinoma.

Urinary CE-MS peptide marker pattern for detection of solid tumors

Urinary profiling datasets, previously acquired by capillary electrophoresis coupled to mass-spectrometry were investigated to identify a general urinary marker pattern for detection of solid tumors by targeting common systemic events associated with tumor-related inflammation. A total of 2,055 urinary profiles were analyzed, derived from a) a cancer group of patients (n = 969) with bladder, prostate, and pancreatic cancers, renal cell carcinoma, and cholangiocarcinoma and b) a control group of patients with benign diseases (n = 556), inflammatory diseases (n = 199) and healthy individuals (n = 331). Statistical analysis was conducted in a discovery set of 676 cancer cases and 744 controls. 193 peptides differing at statistically significant levels between cases and controls were selected and combined to a multi-dimensional marker pattern using support vector machine algorithms. Independent validation in a set of 635 patients (293 cancer cases and 342 controls) showed an AUC of 0.82. Inclusion of age as independent variable, significantly increased the AUC value to 0.85. Among the identified peptides were mucins, fibrinogen and collagen fragments. Further studies are planned to assess the pattern value to monitor patients for tumor recurrence. In this proof-of-concept study, a general tumor marker pattern was developed to detect cancer based on shared biomarkers, likely indicative of cancer-related features.

Insights into the Dichotomous Regulation of SOD2 in Cancer

While loss of antioxidant expression and the resultant oxidant-dependent damage to cellular macromolecules is key to tumorigenesis, it has become evident that effective oxidant scavenging is conversely necessary for successful metastatic spread. This dichotomous role of antioxidant enzymes in cancer highlights their context-dependent regulation during different stages of tumor development. A prominent example of an antioxidant enzyme with such a dichotomous role and regulation is the mitochondria-localized manganese superoxide dismutase SOD2 (MnSOD). SOD2 has both tumor suppressive and promoting functions, which are primarily related to its role as a mitochondrial superoxide scavenger and H₂O₂ regulator. However, unlike true tumor suppressor- or onco-genes, the SOD2 gene is not frequently lost, or rarely mutated or amplified in cancer. This allows SOD2 to be either repressed or activated contingent on context-dependent stimuli, leading to its dichotomous function in cancer. Here, we describe some of the mechanisms that underlie SOD2 regulation in tumor cells. While much is known about the transcriptional regulation of the SOD2 gene, including downregulation by epigenetics and activation by stress response transcription factors, further research is required to understand the post-translational modifications that regulate SOD2 activity in cancer cells. Moreover, future work examining the spatio-temporal nature of SOD2 regulation in the context of changing tumor microenvironments is necessary to allows us to better design oxidant- or antioxidant-based therapeutic strategies that target the adaptable antioxidant repertoire of tumor cells.

Superoxide Dismutases in Pancreatic Cancer

The incidence of pancreatic cancer is increasing as the population ages but treatment advancements continue to lag far behind. The majority of pancreatic cancer patients have a K-ras oncogene mutation causing a shift in the redox state of the cell, favoring malignant proliferation. This mutation is believed to lead to nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation and superoxide overproduction, generating tumorigenic behavior. Superoxide dismutases (SODs) have been studied for their ability to manage the oxidative state of the cell by dismuting superoxide and inhibiting signals for pancreatic cancer growth. In particular, manganese superoxide dismutase has clearly shown importance in cell cycle regulation and has been found to be abnormally low in pancreatic cancer cells as well as the surrounding stromal tissue. Likewise, extracellular superoxide dismutase expression seems to favor suppression of pancreatic cancer growth. With an increased understanding of the redox behavior of pancreatic cancer and key regulators, new treatments are being developed with specific targets in mind. This review summarizes what is known about superoxide dismutases in pancreatic cancer and the most current treatment strategies to be advanced from this knowledge.

Association between MPO-463G > A polymorphism and cancer risk: evidence from 60 case-control studies

BACKGROUND

Though a number of studies have been conducted to explore the association between myeloperoxidase (MPO)-463G > A polymorphism and cancer risk, the results remain inconsistent. Therefore, we performed a meta-analysis to derive a more systematic estimation of this relationship.

METHOD

Relevant studies were searched by PubMed, EMBASE, CNKI, Google Scholar, Ovid, and Cochrane library prior to December 2015. The strength of the association between MPO-463G > A polymorphism and cancer risk was estimated by odds ratios (OR) with 95% confidence interval (95%CI). Cumulative analysis was used to evaluate the stability of results through time.

RESULTS

The current analysis consisted of 16,858 cases and 21,756 controls from 60 studies. Pooled results showed that MPO-463G > A polymorphism were associated with the overall decreased cancer susceptibility in all the genetic models included in this study (additive model: OR = 0.84, 95%CI = 0.76-0.94; allele genetic model: OR = 0.90, 95%CI = 0.840-0.954; recessive genetic model: OR = 0.89, 95%CI = 0.83-0.95). However, in the stratified analysis of cancer type, the significant results were only found in lung cancer (dominant model: OR = 0.93, 95%CI = 0.87-0.99) and digestive system cancer groups (dominant model: OR = 0.67 0.53-0.84; allele frequency model = 0.71, 95%CI = 0.57-0.87), but not in the blood system cancer or breast cancer group. When we further stratified the digestive system cancer group into digestive tract and digestive gland cancer groups, results showed a significant association between allele A of MPO-463G > A and digestive gland cancer in all the genetic models (allele frequency model: OR = 0.63, 95%CI = 0.40-0.99; additive model: OR = 0.41, 95%CI = 0.23-0.73; recessive model: OR = 0.51, 95%CI = 0.29-0.89; dominant model: OR = 0.58, 95%CI = 0.35-0.96), digestive tract cancers in allele frequency model (OR = 0.75, 95%CI = 0.59-0.95), and dominant model (OR = 0.72, 95%CI = 0.56-0.92). When stratified by ethnicity, results demonstrated that the genotype A might be a protect factor for both Caucasians and Asians. In group analysis according to source of controls, significant results were found in population from hospital in all the genetic models. In cumulative analysis, result of allele contrast showed a declining trend and increasingly narrower 95% overall, while the inclination toward non-significant association with lung cancer risk.

CONCLUSIONS

This meta-analysis suggested that MPO-463G > A polymorphism was associated with the overall reduced cancer susceptibility significantly. It might be a more reliable predictor of digestive system cancer instead of lung cancer, blood system cancer, and breast cancer. In cumulative analysis, the stable trend indicated that evidence was sufficient to show the association between MPO-463G > A polymorphism and cancer risk.

Salivary oxidative stress biomarkers in chronic periodontitis and acute coronary syndrome

OBJECTIVES

The study aimed at assessing oxidative stress (OS) biomarker levels in the saliva of patients with chronic periodontitis (CP) and acute coronary syndrome (ACS) and establishing their correlation to periodontal parameters and markers for cardiovascular events.

MATERIALS AND METHODS

The present study enrolled 24 patients with ACS and CP (the ACSCP group), 24 patients with ACS only (the ACS group), 24 patients with CP only (the CP group), and 24 healthy controls. Plaque index (PI), gingival index, bleeding on probing, probing pocket depth (PPD), and clinical attachment loss were recorded. Markers for cardiovascular events included serum high sensitivity C-reactive protein (hsCRP) and plasma fibrinogen. 8-Hydroxydeoxyguanosine (8-OHdG), protein carbonyl (PC), malondialdehyde (MDA), and total antioxidant capacity (TAOC) were used as OS biomarkers.

RESULTS

Salivary 8-OHdG, MDA, and PC levels were significantly higher in the ACSCP, ACS, and CP groups than in healthy controls (p < 0.05). There were significant correlations between salivary PC levels and PI or PPD (p < 0.05) as well as between salivary 8-OHdG levels and all periodontal parameters (p < 0.05). TAOC levels in saliva were correlated to both serum hsCRP and plasma fibrinogen (p < 0.05). Salivary MDA levels were correlated to all periodontal parameters and biomarkers for cardiovascular events (p < 0.05).

CONCLUSIONS

Salivary OS biomarker levels were higher in diseased groups compared to control. They also correlated to clinical periodontal parameters and markers for cardiovascular events in ACS patients, with or without CP.

CLINICAL RELEVANCE

Salivary OS biomarkers could potentially serve as diagnostic tools for cardiovascular and/or periodontal diseases.

Pigment Epithelium-derived Factor (PEDF) Blocks Wnt3a Protein-induced Autophagy in Pancreatic Intraepithelial Neoplasms

An increase in autophagy characterizes pancreatic carcinogenesis, but the signals that regulate this process are incompletely understood. Because canonical Wnt/β-catenin signaling is necessary for the transition from early to advanced pancreatic intraepithelial neoplasia (PanIN) lesions, we assessed whether Wnt ligands and endogenous inhibitors of Wnt signaling modulate autophagy. In this study, canonical Wnt3a ligand induced autophagy markers and vacuoles in murine PanIN cells. Furthermore, pigment epithelium-derived factor (PEDF), a secreted glycoprotein known for its anti-tumor properties, blocked Wnt3a-directed induction of autophagy proteins. Autophagy inhibition was complemented by reciprocal regulation of the oxidative stress enzymes, superoxide dismutase 2 (SOD2) and catalase. Transcriptional control of Sod2 expression was mediated by PEDF-induced NFκB nuclear translocation. PEDF-dependent SOD2 expression in PanIN lesions was recapitulated in a murine model of PanIN formation where PEDF was deleted. In human PanIN lesions, co-expression of PEDF and SOD2 was observed in the majority of early PanIN lesions (47/50, 94%), whereas PEDF and SOD2 immunolocalization in high-grade human PanIN-2/3 was uncommon (7/50, 14%). These results indicate that PEDF regulates autophagy through coordinate Wnt signaling blockade and NFκB activation.

Predicting novel salivary biomarkers for the detection of pancreatic cancer using biological feature-based classification

AIM

The use of saliva as a diagnostic fluid enables non-invasive sampling and thus is a prospective sample for disease tests. This study fully utilized the information from the salivary transcriptome to characterize pancreatic cancer related genes and predict novel salivary biomarkers.

METHODS

We calculated the enrichment scores of gene ontology (GO) and pathways annotated in Kyoto Encyclopedia of Genes and Genomes database (KEGG) for pancreatic cancer-related genes. Annotation of GO and KEGG pathway characterize the molecular features of genes. We employed Random Forest classification and incremental feature selection to identify the optimal features among them and predicted novel pancreatic cancer-related genes.

RESULTS

A total of 2175 gene ontology and 79 KEGG pathway terms were identified as the optimal features to identify pancreatic cancer-related genes. A total of 516 novel genes were predicted using these features. We discovered 29 novel biomarkers based on the expression of these 516 genes in saliva. Using our new biomarkers, we achieved a higher accuracy (92%) for the detection of pancreatic cancer. Another independent expression dataset confirmed that these novel biomarkers performed better than the previously described markers alone.

CONCLUSION

By analyzing the information of the salivary transcriptome, we predict pancreatic cancer-related genes and novel salivary gene markers for detection.

The MnSOD Ala16Val SNP: relevance to human diseases and interaction with environmental factors

The relevance of reactive oxygen species (ROS) production relies on the dual role shown by these molecules in aerobes. ROS are known to modulate several physiological phenomena, such as immune response and cell growth and differentiation; on the other hand, uncontrolled ROS production may cause important tissue and cell damage, such as deoxyribonucleic acid oxidation, lipid peroxidation, and protein carbonylation. The manganese superoxide dismutase (MnSOD) antioxidant enzyme affords the major defense against ROS within the mitochondria, which is considered the main ROS production locus in aerobes. Structural and/or functional single nucleotide polymorphisms (SNP) within the MnSOD encoding gene may be relevant for ROS detoxification. Specifically, the MnSOD Ala16Val SNP has been shown to alter the enzyme localization and mitochondrial transportation, affecting the redox status balance. Oxidative stress may contribute to the development of type 2 diabetes, cardiovascular diseases, various inflammatory conditions, or cancer. The Ala16Val MnSOD SNP has been associated with these and other chronic diseases; however, inconsistent findings between studies have made difficult drawing definitive conclusions. Environmental factors, such as dietary antioxidant intake and exercise have been shown to affect ROS metabolism through antioxidant enzyme regulation and may contribute to explain inconsistencies in the literature. Nevertheless, whether environmental factors may be associated to the Ala16Val genotypes in human diseases still needs to be clarified.

Predictors for detection of cancer in patients with indeterminate biliary stricture and atypical cells on endoscopic retrograde brush cytology

OBJECTIVE

The management of atypical cells on endoscopic retrograde brush cytology (ERBC) in patients with indeterminate biliary stricture is unclear. This study aimed to investigate the detection of cancer (pancreatic and biliary carcinoma) in patients with atypical cells on ERBC and the factors predicting it.

METHODS

From a prospectively maintained cytology database in a tertiary care center, patients with indeterminate biliary stricture and atypical cells on ERBC from 1996 to 2012 were studied. The date of the initial ERBC with atypical cells was identified as time zero. The primary outcome was to study the incidences and Kaplan-Meier estimates for detecting cancer.

RESULTS

In all, 104 patients with 182.8 person-years of follow-up were identified. In 38 (36.5%) patients cancer was detected (19 cholangiocarcinoma, 15 pancreatic cancer, three ampullary cancer and one gallbladder carcinoma) over a mean follow-up of 4.4 months. On Cox regression analysis, the presence of clinical jaundice (hazard ratio [HR] 4.08, 95% CI 1.41-11.8), active alcohol consumption (HR 7.33, 95% CI 1.85-29.1) and elevated carbohydrate antigen 19-9 (CA19-9) level (>33 U/mL) (HR 8.42, 95% CI 1.75-40.6) at the time of ERBC were associated with increased risk for the detection of cancer. Detection of cancer was more common during the first 6 months of follow-up than at any time period thereafter.

CONCLUSION

Elevated CA19-9 level, the presence of clinical jaundice and current alcohol consumption are associated with increased detection of cancer in patients with indeterminate biliary stricture and atypical cells on ERBC.

Correlation between superoxide dismutase 1 and 2 polymorphisms and susceptibility to oral squamous cell carcinoma

Oxidative stress is significant in numerous types of cancer. Tobacco smoke, an important risk factor for oral squamous cell carcinoma (OSCC), is able to generate reactive oxygen species (ROS) and cause oxidative DNA damage. Superoxide dismutase (SOD) is an endogenous antioxidant enzyme that is critical in limiting the oxidative burden effectively. The purpose of this study was to investigate the effects of the mitochondrial SOD2 and Cu/Zn enzyme SOD1 gene polymorphisms on the susceptibility to and clinicopathological characteristics of OSCC, as well as the synergistic effect between these gene polymorphisms and the well-known risk factor of tobacco consumption. Patients with clinically diagnosed OSCC (n=362) and healthy normal individuals (n=358) were investigated for four single nucleotide polymorphisms (SNPs; rs4880, rs5746136, rs1804450 and rs11556620) by polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing methods. Following adjustment for other confounders, no significant difference was observed in the rs5746136 SOD2 SNPs between the patients and controls. However, the incidence of the CT genotype of SOD2 SNP rs4880 was higher in the patients than in normal subjects in the additive model [CT vs. TT; P=0.045; adjusted odds ratio (AOR)=1.484; 95% confidence interval (CI), 1.009–2.182] and in the dominant model (CT/CC vs. TT; P=0.022; AOR=1.559; 95% CI, 1.067–2.278). For those who smoked, the incidence of the CT genotype of rs4880 increased markedly in the patients compared with the controls in the additive model (CT vs. TT; P=0.003; AOR=2.325; 95% CI, 1.330–4.064) and in the dominant model (CT/CC vs. TT; P=0.001; AOR=2.448; 95% CI, 1.417–4.230). For SOD1, polymorphisms at rs1804450 and rs11556620 were not present in any of the OSCC or control subjects. The results suggest that SOD2 rs4880 may be involved in the tumorigenesis of OSCC and may be useful as a genetic susceptibility marker for OSCC.

Polymorphisms in metabolism/antioxidant genes may mediate the effect of dietary intake on pancreatic cancer risk

OBJECTIVES

A source of variation for inconsistent dietary-pancreatic cancer associations may be individuals carrying constitutional metabolism/antioxidant gene variants that differentially benefit compared to homozygous individuals. Seventy-six tag single-nucleotide polymorphisms were genotyped in 13 candidate genes to test differential associations with pancreatic adenocarcinoma.

METHODS

A clinic-based case-control design was used to rapidly ascertain 251 cases and 970 frequency matched controls who provided blood samples and completed a 144-item food frequency questionnaire. Single-nucleotide polymorphisms were evaluated using a dominant genetic model and dietary categories split on controls' median intake. Logistic regression was used to calculate odds ratios and 95% confidence intervals, adjusted for potential confounders.

RESULTS

Significant increased associations (Bonferroni corrected P ≤ 0.0007) were observed for carriers of greater than or equal to 1 minor allele for rs3816257 (glucosidase, α; acid [GAA]) and lower intake of deep-yellow vegetables (1.90 [1.28-2.83]); and carriers of no minor allele for rs12807961 (catalase [CAT]) and high total grains intake (2.48 [1.50-4.09]), whereas those with greater than or equal to 1 minor allele had a decreasing slope (across grains). The reference group was no minor alleles with low dietary intake.

CONCLUSIONS

Interindividual variation in metabolism/antioxidant genes could interact with dietary intake to influence pancreatic cancer risk.

Manganese superoxide dismutase Ile58Thr, catalase C-262T and myeloperoxidase G-463A gene polymorphisms in patients with prostate cancer: relation to advanced and metastatic disease

OBJECTIVE

To evaluate the relationship between manganese superoxide dismutase (MnSOD) Ile58Thr, catalase (CAT) C-262T and myeloperoxidase (MPO) G-463A gene polymorphisms and the susceptibility and clinicopathological characteristics of prostate cancer.

PATIENTS AND METHODS

In all, 155 patients diagnosed with prostate cancer and 195 controls with negative digital rectal examinations and PSA levels of <4 ng/dL were enrolled in this study. MnSOD, CAT and MPO gene polymorphisms were identified by polymerase chain reaction restriction-fragment length polymorphism methods.

RESULTS

The TT genotype in MnSOD Ile58Thr polymorphism, CC genotype in the CAT C-262T polymorphism and the GG genotype in the MPO G-463A polymorphism were the predominant genotypes amongst this Turkish male population. There was no association between MnSOD Ile58Thr polymorphism and prostate cancer. For the CAT C-262T polymorphism, the TT genotype had significantly increased prostate cancer risk compared with the CC genotype. Similarly, the TT genotype had a 1.94- and 3.83-fold increased risk for high-stage disease and metastasis, respectively, when compared with the CC genotype. For the MPO G-463A polymorphism, the GG genotype had 1.78-fold increased risk of prostate cancer compared with the AA genotype. However, no association was found regarding Gleason score, advanced and metastatic prostate cancer risk.

CONCLUSIONS

It seems that there is no association of prostate cancer with MnSOD Ile58Thr polymorphism, whereas the TT genotype in the CAT C-262T polymorphism and the GG genotype in the MPO G-463A polymorphism may be associated with increased prostate cancer risk. The TT genotype in the CAT C-262T gene polymorphism may also be a risk factor in tumour progression and metastasis among Turkish men.

Nutrients from fruit and vegetable consumption reduce the risk of pancreatic cancer

PURPOSE

Pancreatic cancer is a devastating disease for which the role of dietary factors remains inconclusive. Our objective was to evaluate the risk of pancreatic cancer associated with nutrients found in fruits and vegetables and nutrient supplementation using a clinic-based case-control design.

METHODS

Our study included 384 rapidly ascertained cases and 983 controls frequency-matched on age at time of recruitment (in 5-year increments), race, sex, and region of residence. All subjects provided demographic information and completed a 144-item food frequency questionnaire in which they reported no change to their diet within 5 years prior to entering the study. Logistic regression was used to calculate odds ratios and 95 % confidence intervals, adjusted for age, sex, smoking, body mass index, energy intake, and alcohol consumption.

RESULTS

Results show a significant (trend p value < 0.05) inverse association between pancreatic cancer and nutrient/supplement groupings in a dose-dependent manner including magnesium, potassium, selenium, alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin, niacin, total alpha-tocopherol, total vitamin A activity, vitamin B6, and vitamin C. Adjusting for diabetes or total sugar intake did not result in significant changes.

CONCLUSION

We conclude that most nutrients obtained through consumption of fruits and vegetables may reduce the risk of developing pancreatic cancer.

Circadian rhythm disruption in cancer biology

Circadian rhythms show universally a 24-h oscillation pattern in metabolic, physiological and behavioral functions of almost all species. This pattern is due to a fundamental adaptation to the rotation of Earth around its own axis. Molecular mechanisms of generation of circadian rhythms organize a biochemical network in suprachiasmatic nucleus and peripheral tissues, building cell autonomous clock pacemakers. Rhythmicity is observed in transcriptional expression of a wide range of clock-controlled genes that regulate a variety of normal cell functions, such as cell division and proliferation. Desynchrony of this rhythmicity seems to be implicated in several pathologic conditions, including tumorigenesis and progression of cancer. In 2007, the International Agency for Research on Cancer (IARC) categorized "shiftwork that involves circadian disruption [as] probably carcinogenic to humans" (Group 2A in the IARC classification system of carcinogenic potency of an agentagent) (Painting, Firefighting, and Shiftwork; IARC; 2007). This review discusses the potential relation between disruptions of normal circadian rhythms with genetic driving machinery of cancer. Elucidation of the role of clockwork disruption, such as exposure to light at night and sleep disruption, in cancer biology could be important in developing new targeted anticancer therapies, optimizing individualized chronotherapy and modifying lighting environment in workplaces or homes.

Alcohol and tobacco lower the age of presentation in sporadic pancreatic cancer in a dose-dependent manner: a multicenter study

OBJECTIVES

The objective of this study was to examine the association between tobacco and alcohol dose and type and the age of onset of pancreatic adenocarcinoma (PancCa).

METHODS

Prospective data from the Pancreatic Cancer Collaborative Registry were used to examine the association between age of onset and variables of interest including: gender, race, birth country, educational status, family history of PancCa, diabetes status, and tobacco and alcohol use. Statistical analysis included logistic and linear regression, Cox proportional hazard regression, and time-to-event analysis.

RESULTS

The median age to diagnosis for PancCa was 66.3 years (95% confidence intervals (CIs), 64.5-68.0). Males were more likely than females to be smokers (77% vs. 69%, P=0.0002) and heavy alcohol and beer consumers (19% vs. 6%, 34% vs. 19%, P<0.0001). In univariate analysis for effects on PancCa presentation age, the following were significant: gender, alcohol and tobacco use (amount, status and type), family history of PancCa, and body mass index. Both alcohol and tobacco had dose-dependent effects. In multivariate analysis, alcohol status and dose were independently associated with increased risk for earlier PancCa onset with greatest risk occurring in heavy drinkers (HR 1.62, 95% CI 1.04-2.54). Smoking status had the highest risk for earlier onset pancreatic cancer with a HR of 2.69 (95% CI, 1.97-3.68) for active smokers and independent effects for dose (P=0.019). The deleterious effects for alcohol and tobacco appear to resolve after 10 years of abstinence.

CONCLUSIONS

Alcohol and tobacco use are associated with a dose-related increased risk for earlier age of onset of PancCa. Although beer drinkers develop pancreatic cancer at an earlier age than nondrinkers, alcohol type did not have a significant effect after controlling for alcohol dose.

Are centenarians genetically predisposed to lower disease risk?

Our study purpose was to compare a disease-related polygenic profile that combined a total of 62 genetic variants among (i) people reaching exceptional longevity, i.e., centenarians (n = 54, 100-108 years, 48 women) and (ii) ethnically matched healthy controls (n = 87, 19-43 years, 47 women). We computed a 'global' genotype score (GS) for 62 genetic variants (mutations/polymorphisms) related to cardiometabolic diseases, cancer or exceptional longevity, and also specific GS for main disease categories (cardiometabolic risk and cancer risk, including 36 and 24 genetic variations, respectively) and for exceptional longevity (7 genetic variants). The 'global' GS was similar among groups (centenarians: 31.0 ± 0.6; controls 32.0 ± 0.5, P = 0.263). We observed that the GS for hypertension, cancer (global risk), and other types of cancer was lower in the centenarians group compared with the control group (all P < 0.05), yet the difference became non significant after adjusting for sex. We observed significant between-group differences in the frequency of GSTT1 and GSTM1 (presence/absence) genotypes after adjusting for multiple comparisons. The likelihood of having the GSTT1 low-risk (functional) allele was higher in centenarians (odds ratio [OR] 5.005; 95% confidence interval [CI], 1.810-13.839), whereas the likelihood of having the GSTMI low-risk (functional) allele was similar in both groups (OR 1.295; 95% CI, 0.868 -1.931). In conclusion, we found preliminary evidence that Spanish centenarians have a lower genetic predisposition for cancer risk. The wild-type (i.e., functional) genotype of GSTT1, which is associated with lower cancer risk, might be associated with exceptional longevity, yet further studies with larger sample sizes must confirm these findings.

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.

Hepatitis B virus status and risk of pancreatic ductal adenocarcinoma: a case-control study from China

OBJECTIVES

This study was to assess the role of hepatitis B virus (HBV) infection in pancreatic ductal adenocarcinoma (PDAC) risk using a hospital-based case-control design.

METHODS

Patients with pathologically confirmed PDAC (943) and 1128 matched controls were recruited from 2 hospitals. We evaluated the associations between risk of PDAC and age, sex, history of diabetes mellitus (DM), etc. In addition, we examined the interactive effects of HBV status and known risk factors for pancreatic cancer.

RESULTS

Chronic hepatitis B and inactive hepatitis B surface antigen (HBsAg) carrier state (HBsAg positive) had a significantly increased risk of pancreatic cancer, with an adjusted odds ratio of 1.60 (95% confidence interval [CI], 1.15-2.24). Furthermore, significant interactions were detected between a history of DM and chronic hepatitis B and inactive HBsAg positive, but not with antibodies to hepatitis B core antigen (anti-HBc) positive/antibodies to HBsAg (anti-HBs) negative, with an adjusted odds ratio of 5.42 (95% CI, 2.76-10.64), compared with those who were HBsAg negative/anti-HBc negative without a history of DM.

CONCLUSIONS

These results suggest that HBsAg-positive or anti-HBc-positive/anti-HBs-negative patients have an increased risk for PDAC independent of other risk factors. Significant interactions were found between a history of DM and chronic HBV infection for PDAC risk.

The SOD2 C47T polymorphism influences NAFLD fibrosis severity: evidence from case-control and intra-familial allele association studies

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is a complex disease trait where genetic variations and environment interact to determine disease progression. The association of PNPLA3 with advanced disease has been consistently demonstrated but many other modifier genes remain unidentified. In NAFLD, increased fatty acid oxidation produces high levels of reactive oxygen species. Manganese-dependent superoxide dismutase (MnSOD), encoded by the SOD2 gene, plays an important role in protecting cells from oxidative stress. A common non-synonymous polymorphism in SOD2 (C47T; rs4880) is associated with decreased MnSOD mitochondrial targeting and activity making it a good candidate modifier of NAFLD severity.

METHODS

The relevance of the SOD2 C47T polymorphism to fibrotic NAFLD was assessed by two complementary approaches: we sought preferential transmission of alleles from parents to affected children in 71 family trios and adopted a case-control approach to compare genotype frequencies in a cohort of 502 European NAFLD patients.

RESULTS

In the family study, 55 families were informative. The T allele was transmitted on 47/76 (62%) possible occasions whereas the C allele was transmitted on only 29/76 (38%) occasions, p=0.038. In the case control study, the presence of advanced fibrosis (stage>1) increased with the number of T alleles, p=0.008 for trend. Multivariate analysis showed susceptibility to advanced fibrotic disease was determined by SOD2 genotype (OR 1.56 (95% CI 1.09-2.25), p=0.014), PNPLA3 genotype (p=0.041), type 2 diabetes mellitus (p=0.009) and histological severity of NASH (p=2.0×10(-16)).

CONCLUSIONS

Carriage of the SOD2 C47T polymorphism is associated with more advanced fibrosis in NASH.

Common genetic variants in the myeloperoxidase and paraoxonase genes and the related cancer risk: a review

Modern approaches in health care are moving toward the model of "personalized medicine." Today, current research in molecular biology and medicine is focused on developing genomic markers with predictive, therapeutic, and prognostic significance. One of the most widespread and significant genomic markers is the single nucleotide polymorphism (SNP), which represents a variation in DNA sequence when a single nucleotide differs between members of a biological species or paired chromosomes in an individual. Antioxidant defense enzymes break down dangerous reactive compounds, called reactive oxygen species, and prevent DNA strand from carcinogen-specific mutations. It is well known that inherited variations in genes that encode antioxidant defense enzymes may modulate individual susceptibility to cancer. In our previous study we have determined the predictive significance of several SNPs of superoxide dismutase (SOD) and glutathione peroxidase gene families in the context of cancer risk. The present review includes a summary and discussion of the current findings evaluating the role of SNPs of the myeloperoxidase (MPO) and paraoxanase (PON) genes in cancer occurrence and development. We suggest that rs2333227 (MPO_ -463G/A) and rs854560 polymorphisms have a great predictive significance; they could probably be utilized as cancer predictors in the future. Also, we recommend further in-depth research for rs11079344 (MPO), rs8178406 (MPO), rs2243828 (MPO), rs662 (PON1), rs705379 (PON1), and PON1_304A/G polymorphisms. These SNPs may become significant cancer-associated biomarkers.

Clair DK. Manganese superoxide dismutase: beyond life and death

Manganese superoxide dismutase (MnSOD) is a nuclear-encoded antioxidant enzyme that localizes to the mitochondria. Expression of MnSOD is essential for the survival of aerobic life. Transgenic mice expressing a luciferase reporter gene under the control of the human MnSOD promoter demonstrate that the level of MnSOD is reduced prior to the formation of cancer. Overexpression of MnSOD in transgenic mice reduces the incidences and multiplicity of papillomas in a DMBA/TPA skin carcinogenesis model. However, MnSOD deficiency does not lead to enhanced tumorigenicity of skin tissue similarly treated because MnSOD can modulate both the p53-mediated apoptosis and AP-1-mediated cell proliferation pathways. Apoptosis is associated with an increase in mitochondrial levels of p53 suggesting a link between MnSOD deficiency and mitochondrial-mediated apoptosis. Activation of p53 is preventable by application of a SOD mimetic (MnTE-2-PyP(5+)). Thus, p53 translocation to mitochondria and subsequent inactivation of MnSOD explain the observed mitochondrial dysfunction that leads to transcription-dependent mechanisms of p53-induced apoptosis. Administration of MnTE-2-PyP(5+) following apoptosis but prior to proliferation leads to suppression of protein carbonyls and reduces the activity of AP-1 and the level of the proliferating cellular nuclear antigen, without reducing the activity of p53 or DNA fragmentation following TPA treatment. Remarkably, the incidence and multiplicity of skin tumors are drastically reduced in mice that receive MnTE-2-PyP(5+) prior to cell proliferation. The results demonstrate the role of MnSOD beyond its essential role for survival and suggest a novel strategy for an antioxidant approach to cancer intervention.

Superoxide dismutase and nicotinamide adenine dinucleotide phosphate: quinone oxidoreductase polymorphisms and pancreatic cancer risk

OBJECTIVES

Pancreatic carcinoma etiology and molecular pathogenesis is weakly understood. According to the assumption that genetic variation in carcinogen metabolism further modifies the risk of exposure-related cancers, an association of functional polymorphisms in oxidative stress-modifying genes superoxide dismutase 2 (SOD2 [Ala16Val, rs4880]), SOD3 (Arg231Gly, rs1799895), nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase (NQO1 [Pro187Ser, rs1800566], and NQO2 (Phe47Leu, rs1143684) with pancreatic cancer risk was studied.

METHODS

Polymorphisms were studied by allelic discrimination.

RESULTS

In a hospital-based case-control study on 500 individuals (235 cases and 265 controls) of Czech white origin, SOD2, SOD3, NQO1, and NQO2 polymorphisms showed no significant association with pancreatic cancer risk. Major lifestyle factors such as smoking and alcohol, coffee, or tea consumption did not modify the effect of the studied polymorphisms.

CONCLUSIONS

The first European study of the SOD2, SOD3, NQO1, and NQO2 roles in pancreatic cancer etiology did not find significant associations. Despite this observation, other populations with different lifestyle(s) may be at risk and should be further studied.

Mn-SOD and CuZn-SOD polymorphisms and interactions with risk factors in gastric cancer

AIM

To investigate the effects of superoxide dismutase (SOD) polymorphisms (rs4998557, rs4880), Helicobacter pylori (H. pylori) infection and environmental factors in gastric cancer (GC) and malignant potential of gastric precancerous lesions (GPL).

METHODS

Copper-zinc superoxide dismutase (SOD1, CuZn-SOD)-G7958A (rs4998557) and manganese superoxide dismutase (SOD2, Mn-SOD)-Val16Ala (rs4880) polymorphisms were genotyped by SNaPshot multiplex polymerase chain reaction (PCR) in 145 patients with GPL (87 cases of gastric ulcer, 33 cases of gastric polyps and 25 cases of atrophic gastritis), 140 patients with GC and 147 healthy controls. H. pylori infection was detected by immunoblotting analysis.

RESULTS

The SOD1-7958A allele was associated with a higher risk of gastric cancer [odds ratio (OR) = 3.01, 95% confidence intervals (95% CI): 1.83-4.95]. SOD2-16Ala/Val genotype was a risk factor for malignant potential of GPL (OR = 2.04, 95% CI: 1.19-3.49). SOD2-16Ala/- genotype increased the risk of gastric cancer (OR = 2.85, 95% CI: 1.66-4.89). SOD1-7958A/- genotype, SOD2-16Ala/- genotype, alcohol drinking, positive family history and type I H. pylori infection were associated with risk of gastric cancer, and there were additive interactions between the two genotypes and the other three risk factors. SOD2-16Ala/Val genotype and positive family history were associated with malignant potential of GPL and jointly contributed to a higher risk for malignant potential of GPL (OR = 7.71, 95% CI: 2.10-28.22). SOD1-7958A/- genotype and SOD2-16Ala/- genotype jointly contributed to a higher risk for gastric cancer (OR = 6.43, 95% CI: 3.20-12.91).

CONCLUSION

SOD1-7958A/- and SOD2-16Ala/-genotypes increase the risk of gastric cancer in Chinese Han population. SOD2-16Ala/-genotype is associated with malignant potential of GPL.

The MPO -463G>A polymorphism and cancer risk: a meta-analysis based on 43 case-control studies

Myeloperoxidase (MPO) is an endogenous oxidant enzyme that generates reactive oxygen species and plays an important role in the aetiology of cancer. The MPO -463G>A polymorphism influences MPO transcription and has been implicated in cancer risk. However, results from published studies on the association between the MPO -463G>A polymorphism and risk of cancer are conflicting. To derive a more precise estimation of association between the MPO -463G>A polymorphism and risk of cancer, we performed a meta-analysis based on 43 case-control studies, including a total of 14 171 cancer cases and 17 319 controls. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. Overall, individuals with the -463A allele had a 0.93-fold lower cancer risk in a dominant model (OR = 0.93, 95% CI = 0.87-1.00). In the stratified analyses, we observed a similar association in European populations (heterozygote comparison: OR = 0.90, 95% CI = 0.82-0.99) and hospital-based studies (dominant model: OR = 0.88, 95% CI = 0.79-0.99). When stratified by cancer type, however, no significant association was found. The results suggested that the MPO -463A allele does not contribute to the development of cancer. Additional well-designed large studies are required to validate these findings in different populations.

Upregulation of FOXM1 induces genomic instability in human epidermal keratinocytes

Background

The human cell cycle transcription factor FOXM1 is known to play a key role in regulating timely mitotic progression and accurate chromosomal segregation during cell division. Deregulation of FOXM1 has been linked to a majority of human cancers. We previously showed that FOXM1 was upregulated in basal cell carcinoma and recently reported that upregulation of FOXM1 precedes malignancy in a number of solid human cancer types including oral, oesophagus, lung, breast, kidney, bladder and uterus. This indicates that upregulation of FOXM1 may be an early molecular signal required for aberrant cell cycle and cancer initiation.

Results

The present study investigated the putative early mechanism of UVB and FOXM1 in skin cancer initiation. We have demonstrated that UVB dose-dependently increased FOXM1 protein levels through protein stabilisation and accumulation rather than de novo mRNA expression in human epidermal keratinocytes. FOXM1 upregulation in primary human keratinocytes triggered pro-apoptotic/DNA-damage checkpoint response genes such as p21, p38 MAPK, p53 and PARP, however, without causing significant cell cycle arrest or cell death. Using a high-resolution Affymetrix genome-wide single nucleotide polymorphism (SNP) mapping technique, we provided the evidence that FOXM1 upregulation in epidermal keratinocytes is sufficient to induce genomic instability, in the form of loss of heterozygosity (LOH) and copy number variations (CNV). FOXM1-induced genomic instability was significantly enhanced and accumulated with increasing cell passage and this instability was increased even further upon exposure to UVB resulting in whole chromosomal gain (7p21.3-7q36.3) and segmental LOH (6q25.1-6q25.3).

Conclusion

We hypothesise that prolonged and repeated UVB exposure selects for skin cells bearing stable FOXM1 protein causes aberrant cell cycle checkpoint thereby allowing ectopic cell cycle entry and subsequent genomic instability. The aberrant upregulation of FOXM1 serves as a 'first hit' where cells acquire genomic instability which in turn predisposes cells to a 'second hit' whereby DNA-damage checkpoint response (eg. p53 or p16) is abolished to allow damaged cells to proliferate and accumulate genetic aberrations/mutations required for cancer initiation.

The association between periodontal disease and cancer: a review of the literature

OBJECTIVES

Periodontal disease has long been linked to many systemic diseases, and recently a link between periodontal disease and cancer has been established. The purpose of this paper is to review the literature to explore the evidence to date of a relationship between periodontal disease and cancer. In addition, the main hypotheses for the association are discussed along with challenges in evaluating the evidence.

DATA/SOURCES/STUDY SELECTION

In this review, English-language papers studying the relationship between periodontal disease or tooth loss in humans and increased risk of several types of cancers along with overall cancer risk between 1990 and April 2009 were reviewed.

CONCLUSIONS

The most consistent increased risk was noted in studies of oral and esophageal cancers and periodontal disease. Gastric and pancreatic cancers had an association in most but not all studies. Lung, prostate, hematologic and other cancers were less consistently associated or did not have sufficient studies to determine a predictable pattern. Studies to date indicate a positive correlation between several forms of cancer and periodontal disease.

Antioxidant genes, diabetes and dietary antioxidants in association with risk of pancreatic cancer

To test the hypothesis that polymorphic variants of antioxidant genes modify the risk of pancreatic cancer, we examined seven single-nucleotide polymorphisms (SNPs) of genes coding for superoxide dismutase (SOD) 2, glutathione S-transferase alpha 4 (GSTA4), catalase and glutathione peroxidase in 575 patients with pancreatic adenocarcinoma and 648 healthy controls in a case-control study. Information on risk factors was collected by personal interview and dietary information was collected by a self-administered food frequency questionnaire. Genotypes were determined using the Taqman method. Adjusted odds ratio (AOR) and 95% confidence interval (CI) were estimated by unconditional logistic regression. No significant main effect of genotype was observed. A borderline significant interaction between diabetes and SOD2 Ex2+24T>C CT/TT genotype was observed (P(interaction) = 0.051); the AORs (95% CI) were 0.98 (0.73-1.32) for non-diabetics carrying the CT/TT genotype, 1.73 (0.94-3.18) for diabetics carrying the CC genotype and 3.49 (2.22-5.49) for diabetics carrying the CT/TT genotype compared with non-diabetics carrying the CC genotype. Moreover, the SOD2 -1221G>A AA genotype carriers had a significantly increased risk for pancreatic cancer among those with a low dietary vitamin E intake but decreased risk among those with a high vitamin E intake (P(interaction) = 0.002). There was a non-significant interaction between diabetes and GSTA4 Ex5-64G>A genotypes (P(interaction) = 0.078). No significant interaction between genotype with cigarette smoking or vitamin C intake was observed. These data suggest that genetic variations in antioxidant defenses modify the risk of pancreatic cancer in diabetics or individuals with a low dietary vitamin E intake.

Are elite endurance athletes genetically predisposed to lower disease risk?

We compared a polygenic profile that combined 33 disease risk-related mutations and polymorphisms among nonathletic healthy control subjects and elite endurance athletes. The study sample comprised 100 healthy Spanish male nonathletic (sedentary) control subjects and 100 male elite endurance athletes. We analyzed 33 disease risk-related mutations and polymorphisms. We computed a health-related total genotype score (TGS, 0-100) from the accumulated combination of the 33 variants. We did not observe significant differences in genotype or allele distributions among groups, except for the rs4994 polymorphism (P < 0.001). The computed health-related TGS was similar among groups (23.8 +/- 1.0 vs. 24.2 +/- 0.8 in control subjects and athletes, respectively; P = 0.553). Similar results were obtained when computing specific TGSs for each main disease category (cardiovascular disease and cancer). We observed no evidence that male elite endurance athletes are genetically predisposed to have lower disease risk than matched nonathletic control subjects.

Myeloperoxidase: molecular mechanisms of action and their relevance to human health and disease

Myeloperoxidase (MPO) is a heme-containing peroxidase abundantly expressed in neutrophils and to a lesser extent in monocytes. Enzymatically active MPO, together with hydrogen peroxide and chloride, produces the powerful oxidant hypochlorous acid and is a key contributor to the oxygen-dependent microbicidal activity of phagocytes. In addition, excessive generation of MPO-derived oxidants has been linked to tissue damage in many diseases, especially those characterized by acute or chronic inflammation. It has become increasingly clear that MPO exerts effects that are beyond its oxidative properties. These properties of MPO are, in many cases, independent of its catalytic activity and affect various processes involved in cell signaling and cell-cell interactions and are, as such, capable of modulating inflammatory responses. Given these diverse effects, an increased interest has emerged in the role of MPO and its downstream products in a wide range of inflammatory diseases. In this article, our knowledge pertaining to the biologic role of MPO and its downstream effects and mechanisms of action in health and disease is reviewed and discussed.

Clair DK. Regulation of superoxide dismutase genes: implications in disease

Numerous short-lived and highly reactive oxygen species (ROS) such as superoxide (O2(.-)), hydroxyl radical, and hydrogen peroxide are continuously generated in vivo. Depending upon concentration, location, and intracellular conditions, ROS can cause toxicity or act as signaling molecules. The cellular levels of ROS are controlled by antioxidant enzymes and small-molecule antioxidants. As major antioxidant enzymes, superoxide dismutases (SODs), including copper-zinc superoxide dismutase (Cu/ZnSOD), manganese superoxide dismutase, and extracellular superoxide dismutase, play a crucial role in scavenging O2(.-). This review focuses on the regulation of the sod genes coding for these enzymes, with an emphasis on the human genes. Current knowledge about sod structure and regulation is summarized and depicted as diagrams. Studies to date on genes coding for Cu/ZnSOD (sod1) are mostly focused on alterations in the coding region and their associations with amyotrophic lateral sclerosis. Evaluation of nucleotide sequences reveals that regulatory elements of the sod2 gene reside in both the noncoding and the coding region. Changes associated with sod2 lead to alterations in expression levels as well as protein function. We also discuss the structural basis for the changes in SOD expression associated with pathological conditions and where more work is needed to establish the relationship between SODs and diseases.

Antioxidant activity of sulfur and selenium: a review of reactive oxygen species scavenging, glutathione peroxidase, and metal-binding antioxidant mechanisms

It is well known that oxidation caused by reactive oxygen species (ROS) is a major cause of cellular damage and death and has been implicated in cancer, neurodegenerative, and cardiovascular diseases. Small-molecule antioxidants containing sulfur and selenium can ameliorate oxidative damage, and cells employ multiple antioxidant mechanisms to prevent this cellular damage. However, current research has focused mainly on clinical, epidemiological, and in vivo studies with little emphasis on the antioxidant mechanisms responsible for observed sulfur and selenium antioxidant activities. In addition, the antioxidant properties of sulfur compounds are commonly compared to selenium antioxidant properties; however, sulfur and selenium antioxidant activities can be quite distinct, with each utilizing different antioxidant mechanisms to prevent oxidative cellular damage. In the present review, we discuss the antioxidant activities of sulfur and selenium compounds, focusing on several antioxidant mechanisms, including ROS scavenging, glutathione peroxidase, and metal-binding antioxidant mechanisms. Findings of several recent clinical, epidemiological, and in vivo studies highlight the need for future studies that specifically focus on the chemical mechanisms of sulfur and selenium antioxidant behavior.

Genetic polymorphisms in nitric oxide synthase genes modify the relationship between vegetable and fruit intake and risk of non-Hodgkin lymphoma

Oxidative damage caused by reactive oxygen species and other free radicals is involved in carcinogenesis. It has been suggested that high vegetable and fruit intake may reduce the risk of non-Hodgkin lymphoma (NHL) as vegetables and fruit are rich in antioxidants. The aim of this study is to evaluate the interaction of vegetable and fruit intake with genetic polymorphisms in oxidative stress pathway genes and NHL risk. This hypothesis was investigated in a population-based case-control study of NHL and NHL histologic subtypes in women from Connecticut, including 513 histologically confirmed incident cases and 591 randomly selected controls. Gene-vegetable/fruit joint effects were estimated using unconditional logistic regression model. The false discovery rate method was applied to adjust for multiple comparisons. Significant interactions with vegetable and fruit intake were mainly found for genetic polymorphisms on nitric oxide synthase (NOS) genes among those with diffuse large B-cell lymphoma and follicular lymphoma. Two single nucleotide polymorphisms in the NOS1 gene were found to significantly modify the association between total vegetable and fruit intake and risk of NHL overall, as well as the risk of follicular lymphoma. When vegetables, bean vegetables, cruciferous vegetables, green leafy vegetables, red vegetables, yellow/orange vegetables, fruit, and citrus fruits were examined separately, strong interaction effects were narrowed to vegetable intake among patients with diffuse large B-cell lymphoma. Our results suggest that genetic polymorphisms in oxidative stress pathway genes, especially in the NOS genes, modify the association between vegetable and fruit intake and risk of NHL.