Oxidative stress and hypoxia-inducible factors (HIFs) have been implicated in the pathogenesis of diabetic cardiovascular and renal diseases. Reactive oxygen species (ROS) mediate physiological and pathophysiological processes, being involved in the modulation of cell signaling, differentiation, and survival, but also in cyto- and genotoxic damage. As master regulators of glycolytic metabolism and oxygen homeostasis, HIFs have been largely studied for their role in cell survival in hypoxic conditions. However, in addition to hypoxia, other stimuli can regulate HIFs stability and transcriptional activity, even in normoxic conditions. Among these, a regulatory role of ROS and their byproducts on HIFs, particularly the HIF-1α isoform, has received growing attention in recent years. On the other hand, HIF-1α and HIF-2α exert mutually antagonistic effects on oxidative damage. In diabetes, redox-mediated HIF-1α deregulation contributes to the onset and progression of cardiovascular and renal complications, and recent findings suggest that deranged HIF signaling induced by hyperglycemia and other cellular stressors associated with metabolic disorders may cause mitochondrial dysfunction, oxidative stress, and inflammation. Understanding the mechanisms of mutual regulation between HIFs and redox factors and the specific contribution of the two main isoforms of HIF-α is fundamental to identify new therapeutic targets for vascular complications of diabetes.
Carbonyl stress is a condition characterized by an increase in the steady-state levels of reactive carbonyl species (RCS) that leads to accumulation of their irreversible covalent adducts with biological molecules. RCS are generated by the oxidative cleavage and cellular metabolism of lipids and sugars. In addition to causing damage directly, the RCS adducts, advanced glycation end-products (AGEs) and advanced lipoxidation end-products (ALEs), cause additional harm by eliciting chronic inflammation through receptor-mediated mechanisms. Hyperglycemia- and dyslipidemia-induced carbonyl stress plays a role in diabetic cardiovascular complications and diabetes-related cancer risk. Moreover, the increased dietary exposure to AGEs/ALEs could mediate the impact of the modern, highly processed diet on cardiometabolic and cancer risk. Finally, the transient carbonyl stress resulting from supraphysiological postprandial spikes in blood glucose and lipid levels may play a role in acute proinflammatory and proatherogenic changes occurring after a calorie dense meal. These findings underline the potential importance of carbonyl stress as a mediator of the cardiometabolic and cancer risk linked to today's unhealthy diet. In this review, current knowledge in this field is discussed along with future research courses to offer new insights and open new avenues for therapeutic interventions to prevent diet-associated cardiometabolic disorders and cancer.
Twenty years have passed since Brownlee and colleagues proposed a single unifying mechanism for diabetic complications, introducing a turning point in this field of research. For the first time, reactive oxygen species (ROS) were identified as the causal link between hyperglycemia and four seemingly independent pathways that are involved in the pathogenesis of diabetes-associated vascular disease. Before and after this milestone in diabetes research, hundreds of articles describe a role for ROS, but the failure of clinical trials to demonstrate antioxidant benefits and some recent experimental studies showing that ROS are dispensable for the pathogenesis of diabetic complications call for time to reflect. This twenty-year journey focuses on the most relevant literature regarding the main sources of ROS generation in diabetes and their role in the pathogenesis of cell dysfunction and diabetic complications. To identify future research directions, this review discusses the evidence in favor and against oxidative stress as an initial event in the cellular biochemical abnormalities induced by hyperglycemia. It also explores possible alternative mechanisms, including carbonyl stress and the Warburg effect, linking glucose and lipid excess, mitochondrial dysfunction, and the activation of alternative pathways of glucose metabolism leading to vascular cell injury and inflammation.
Both type 2 (T2DM) and type 1 (T1DM) diabetes mellitus confer an increased risk of pancreatic cancer in humans. The magnitude and temporal trajectory of the risk conferred by the two forms of diabetes are similar, suggesting a common mechanism. Carbonyl stress is a hallmark of hyperglycemia and dyslipidemia, which accompanies T2DM, prediabetes, and obesity. Accumulating evidence demonstrates that diabetes promotes pancreatic ductal adenocarcinoma (PDAC) in experimental models of T2DM, a finding recently confirmed in a T1DM model. The carbonyl stress markers advanced glycation end-products (AGEs), the levels of which are increased in diabetes, were shown to markedly accelerate tumor development in a mouse model of Kras-driven PDAC. Consistently, inhibition of AGE formation by trapping their carbonyl precursors (i.e., reactive carbonyl species, RCS) prevented the PDAC-promoting effect of diabetes. Considering the growing attention on carbonyl stress in the onset and progression of several cancers, including breast, lung and colorectal cancer, this review discusses the mechanisms by which glucose and lipid imbalances induce a status of carbonyl stress, the oncogenic pathways activated by AGEs and their precursors RCS, and the potential use of carbonyl-scavenging agents and AGE inhibitors in PDAC prevention and treatment, particularly in high-risk diabetic individuals.
Background Type 1 and 2 diabetes confer an increased risk of pancreatic cancer (PaC) of similar magnitude, suggesting a common mechanism. The recent finding that PaC incidence increases linearly with increasing fasting glucose levels supports a central role for hyperglycaemia, which is known to cause carbonyl stress and advanced glycation end-product (AGE) accumulation through increased glycolytic activity and non-enzymatic reactions. This study investigated the impact of hyperglycaemia on invasive tumour development and the underlying mechanisms involved. Methods Pdx1-Cre;LSL-Kras G12D/+ mice were interbred with mitosis luciferase reporter mice, rendered diabetic with streptozotocin and treated or not with carnosinol (FL-926-16), a selective scavenger of reactive carbonyl species (RCS) and, as such, an inhibitor of AGE formation. Mice were monitored for tumour development by in vivo bioluminescence imaging. At the end of the study, pancreatic tissue was collected for histology/immunohistochemistry and molecular analyses. Mechanistic studies were performed in pancreatic ductal adenocarcinoma cell lines challenged with high glucose, glycolysis- and glycoxidation-derived RCS, their protein adducts AGEs and sera from diabetic patients. Results Cumulative incidence of invasive PaC at 22 weeks of age was 75% in untreated diabetic vs 25% in FL-926-16-gtreated diabetic and 8.3% in non-diabetic mice. FL-926-16 treatment suppressed systemic and pancreatic carbonyl stress, extracellular signal-regulated kinases (ERK) 1/2 activation, and nuclear translocation of Yes-associated protein (YAP) in pancreas. In vitro, RCS scavenging and AGE elimination completely inhibited cell proliferation stimulated by high glucose, and YAP proved essential in mediating the effects of both glucose-derived RCS and their protein adducts AGEs. However, RCS and AGEs induced YAP activity through distinct pathways, causing reduction of Large Tumour Suppressor Kinase 1 and activation of the Epidermal Growth Factor Receptor/ERK signalling pathway, respectively. Conclusions An RCS scavenger and AGE inhibitor prevented the accelerating effect of diabetes on PainINs progression to invasive PaC, showing that hyperglycaemia promotes PaC mainly through increased carbonyl stress. In vitro experiments demonstrated that both circulating RCS/AGEs and tumour cell-derived carbonyl stress generated by excess glucose metabolism induce proliferation by YAP activation, hence providing a molecular mechanism underlying the link between diabetes and PaC (and cancer in general).
Obesity, metabolic syndrome, and diabetes mellitus have reached epidemic proportions in developed countries, where they constitute a major health challenge in the adult population. Treatment of diabetes relies on a combination of strict control of hyperglycemia and hypertension, changes in dietary and activity habits, and obesity reduction. Although long-term marked weight loss is a difficult goal to achieve because of poor compliance, diet adjustments consisting of intake of functional foods and supplements are often more acceptable for the patient in view of their naturopathic connotation. This chapter deals with the vast literature that has appeared in the last decade on specific food nutrients with purported beneficial effects to prevent type 2 diabetes and its microvascular and macrovascular complications, including nephropathy, retinopathy, ischemic heart disease, and cerebrovascular disease. Numerous clinical and experimental studies support the favorable effects of nutraceuticals, more often of plant origin. This is hardly surprising because scientific interest in these foods has often been prompted by folk medicine tenets and traditional, ethnic fare. Non-plant-derived dietary supplements are also discussed. However, the challenging step, which has not been attained yet, remains the preparation of adequate diet protocols that may efficaciously convey the collected data. On one hand, these protocols should suit the individual patient's medical needs, life habits, and cultural/religious beliefs. On the other hand, they should combine, based on a sound scientific rationale, a spectrum of food supplements of proved beneficial properties to reach an optimal, synergistic effect.
Recent advances in nutritional therapy are promising tools to complement drug treatment in order to delay inception and progression of diabetic nephropathy. This review deals with practical, evidence-based recommendations for diet prescription in consideration of general guidelines, and the patient's cultural and ethnic background. Most carbohydrates, fats, and protein should be provided by fruits and whole-grain and fiber-rich vegetables, within the general outline of the Mediterranean and the Dietary Approaches to Stop Hypertension (DASH) diets. There are scientific reasons for favoring protein from vegan sources, which are also rich in vitamins and minerals, and, within animal sources, protein from fish and white meat. Total protein intake should be controlled, for both its excess and considerable reductions are associated with unfavorable outcome. The personalized diet should also consider local/ethnic staples, such as olive oil and other vegan foods, which are currently investigated for their advantageous role in diabetic nephropathy. They could easily fit in the standard guidelines since they match patient's dietary habits, a fact that should enhance diet prescription compliance.
This article is a critical overview of recent contributions on the dietary corrections and the foods that have been claimed to delay or hinder the onset of diabetic nephropathy (DN) and its progression to end-stage renal disease. Innovative dietary and behavioral approaches to the prevention and therapy of DN appear to be the most captivating in consideration of the rather well-established protocols for glucose and blood pressure control in use. In addition to restricted caloric intake to contrast obesity and the metabolic syndrome, adjustments in the patient's macronutrients intake, and in particular some degree of reduction in protein, have been long considered in the prevention of DN progression. More recently, the focus has shifted to the source of proteins and the content of glycotoxins in the diet as well as to the role of specific micronutrients. Few clinical trials have specifically addressed the role of those micronutrients associated with diet proteins that show the most protective effect against DN. Research on clinical outcome and mechanisms of action of such micronutrients appears the most promising in order to develop both effective intervention on nutritional education of the patient and selection of functional foods capable of contrasting the onset and progression of DN.
OBJECTIVE:Galectin-3 is constitutively expressed in bone cells and was recently shown to modulate osteogenic transdifferentiation of vascular smooth muscle cells and atherosclerotic calcification. However, the role of galectin-3 in bone physiology is largely undefined. To address this issue, we analyzed (1) the skeletal features of 1-, 3- and 6-month-old galectin-3 null (Lgals3-/-) and wild type (WT) mice and (2) the differentiation and function of osteoblasts and osteoclasts derived from these animals. METHODS:Long bone phenotype, gene expression profile, and remodeling were investigated by micro-computed tomography, real time-PCR, static and dynamic histomorphometry, and assessment of biochemical markers of bone resorption and formation. Bone competence was also evaluated by biomechanical testing at 3 months. In vitro, the effects of galectin-3 deficiency on bone cell differentiation and function were investigated by assessing (a) gene expression of osteoblast markers, alkaline phosphatase activity, mineralization assay, and WNT/β-catenin signaling (of which galectin-3 is a known regulator) in osteoblasts; and (b) tartrate-resistant acid phosphatase activity and bone resorption activity in osteoclasts. RESULTS:Lgals3-/- mice revealed a wide range of age-dependent alterations including lower bone formation and higher bone resorption, accelerated age-dependent trabecular bone loss (p < 0.01 vs. WT at 3 months) and reduced bone strength (p < 0.01 vs. WT at 3 months). These abnormalities were accompanied by a steady inflammatory state, as revealed by higher bone expression of the pro-inflammatory cytokines interleukin (IL)-1β and IL-6 (p < 0.001 vs. WT at 3 months), increased content of osteal macrophages (p < 0.01 vs. WT at 3 months), and reduced expression of markers of alternative (M2) macrophage activation. Lgals3-/- osteoblasts and osteoclasts showed impaired terminal differentiation, reduced mineralization capacity (p < 0.01 vs. WT cells) and resorption activity (p < 0.01 vs. WT cells). Mechanistically, impaired differentiation and function of Lgals3-/- osteoblasts was associated with altered WNT/β-catenin signaling (p < 0.01 vs. WT cells). CONCLUSIONS:These data provide evidence for a contribution of galectin-3 to bone cell maturation and function, bone remodeling, and biomechanical competence, thus identifying galectin-3 as a promising therapeutic target for age-related disorders of bone remodeling.
Diabetes is an established risk factor for pancreatic cancer (PaC), together with obesity, a Western diet, and tobacco smoking. The common mechanistic link might be the accumulation of advanced glycation end‐products (AGEs), which characterizes all of the above disease conditions and unhealthy habits. Surprisingly, however, the role of AGEs in PaC has not been examined yet, despite the evidence of a tumour‐promoting role of receptor for advanced glycation end‐products (RAGE), the receptor for AGEs. Here, we tested the hypothesis that AGEs promote PaC through RAGE activation. To this end, we investigated the effects of the AGE Nϵ‐carboxymethyllysine (CML) in human pancreatic ductal adenocarcinoma (PDA) cell lines and in a mouse model of Kras‐driven PaC interbred with a bioluminescent model of proliferation. Tumour growth was monitored in vivo by bioluminescence imaging and confirmed by histology. CML promoted PDA cell growth and RAGE expression, in a concentration‐dependent and time‐dependent manner, and activated downstream tumourigenic signalling pathways. These effects were counteracted by RAGE antagonist peptide (RAP). Exogenous AGE administration to PaC‐prone mice induced RAGE upregulation in pancreatic intraepithelial neoplasias (PanINs) and markedly accelerated progression to invasive PaC. At 11 weeks of age (6 weeks of CML treatment), PaC was observed in eight of 11 (72.7%) CML‐treated versus one of 11 (9.1%) vehicle‐treated [control (Ctr)] mice. RAP delayed PanIN development in Ctr mice but failed to prevent PaC promotion in CML‐treated mice, probably because of competition with soluble RAGE for binding to AGEs and/or compensatory upregulation of the RAGE homologue CD166/ activated leukocyte cell adhesion molecule, which also favoured tumour spread. These findings indicate that AGEs modulate the development and progression of PaC through receptor‐mediated mechanisms, and might be responsible for the additional risk conferred by diabetes and other conditions characterized by increased AGE accumulation. Finally, our data suggest that an AGE reduction strategy, instead of RAGE inhibition, might be suitable for the risk management and prevention of PaC. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Background and Purpose The advanced glycation end products (AGEs) participate in the pathogenesis of diabetic nephropathy (DN) by promoting renal inflammation and injury. L‐carnosine acts as a quencher of the AGE precursors reactive carbonyl species (RCS), but is rapidly inactivated by carnosinase. In this study, we evaluated the effect of FL‐926‐16, a carnosinase‐resistant and bioavailable carnosine derivative, on the onset and progression of DN in db / db mice. Experimental Approach Adult male db / db mice and coeval db / m controls were left untreated or treated with FL‐926‐16 (30 mg·kg −1 body weight) from weeks 6 to 20 (prevention protocol) or from weeks 20 to 34 (regression protocol). Key Results In the prevention protocol, FL‐926‐16 significantly attenuated increases in creatinine (−80%), albuminuria (−77%), proteinuria (−75%), mean glomerular area (−34%), fractional (−40%) and mean (−42%) mesangial area in db / db mice. This protective effect was associated with a reduction in glomerular matrix protein expression and cell apoptosis, circulating and tissue oxidative and carbonyl stress, and renal inflammatory markers, including the NLRP3 inflammasome. In the regression protocol, the progression of DN was completely blocked, although not reversed, by FL‐926‐16. In cultured mesangial cells, FL‐926‐16 prevented NLRP3 expression induced by RCS but not by the AGE N ε ‐carboxymethyllysine. Conclusion and Implications FL‐926‐16 is effective at preventing the onset of DN and halting its progression in db / db mice by quenching RCS, thereby reducing the accumulation of their protein adducts and the consequent inflammatory response. In a future perspective, this novel compound may represent a promising AGE‐reducing approach for DN therapy.
In this article, there was a mistake in the assembly of Fig. 4. The image files shown in panels E – H of …
Galectin-3 is an important modulator of several biological functions. It has been implicated in numerous disease conditions, particularly in the long-term complications of diabetes because of its ability to bind the advanced glycation/lipoxidation end products that accumulate in target organs and exert their toxic effects by triggering proinflammatory and prooxidant pathways. Recent evidence suggests that galectin-3 may also participate in the development of obesity and type 2 diabetes. It has been shown that galectin-3 levels are higher in obese and diabetic individuals and parallel deterioration of glucose homeostasis. Two studies in galectin-3 knockout mice fed a high-fat diet (HFD) have shown increased adiposity and adipose tissue and systemic inflammation associated with altered glucose homeostasis, suggesting that galectin-3 negatively modulates the responsiveness of innate and adaptive immunity to overnutrition. However, these studies have also shown that impaired glucose homeostasis occurs in galectin-3 knockout animals independently of obesity. Moreover, another study reported decreased weight and fat mass in HFD-fed galectin-3 knockout mice. In vitro, galectin-3 was found to stimulate differentiation of preadipocytes into mature adipocytes. Altogether, these data indicate that galectin-3 deserves further attention in order to clarify its role as a potential player and therapeutic target in obesity and type 2 diabetes.
Galectin-3 has been increasingly recognized as an important modulator of several biological functions, by interacting with several molecules inside and outside the cell, and an emerging player in numerous disease conditions. Galectin-3 exerts various and sometimes contrasting effects according to its location, type of injury or site of damage. Strong evidence indicates that galectin-3 participates in the pathogenesis of diabetic complications via its receptor function for advanced glycation end-products (AGEs) and advanced lipoxidation end-products (ALEs). AGEs/ALEs are produced to an increased extent in target organs of complications, such as kidney and vessels; here, lack of galectin3 impairs their removal, leading to accelerated damage. In contrast, in the liver, AGE/ALE tissue content and injury are decreased, because lack of galectin-3 results in reduced uptake and tissue accumulation of these by-products. Some of these effects can be explained by changes in the expression of receptor for AGEs (RAGE), associated with galectin-3 deletion and consequent changes in AGE/ALE tissue levels. Furthermore, galectin-3 might exert AGE/ALE-and RAGE-independent effects, favoring resolution of inflammation and modulating fibrogenesis and ectopic osteogenesis. These effects are mediated by intracellular and extracellular galectin-3, the latter via interaction with N-glycans at the cell surface to form lattice structures. Recently, galectin-3 has been implicated in the development of metabolic disorders because it favors glucose homeostasis and prevents the deleterious activation of adaptive and innate immune response to obesogenic/diabetogenic stimuli. In conclusion, galectin-3 is an emerging all-out player in metabolic disorders and their complications that deserves further investigation as the potential target of therapeutic intervention.
AIMS:Vascular calcification correlates with inflammation and plaque instability in a dual manner, depending on the spotty/granular (micro) or sheet-like/lamellated (macro) pattern of calcification. Modified lipoproteins trigger both inflammation and calcification via receptors for advanced lipoxidation/glycation endproducts (ALEs/AGEs). This study compared the roles of galectin-3 and receptor for AGEs (RAGE), two ALEs/AGEs-receptors with diverging effects on inflammation and bone metabolism, in the process of vascular calcification.METHODS AND RESULTS:We evaluated galectin-3 and RAGE expression/localization in 62 human carotid plaques and its relation to calcification pattern, plaque phenotype, and markers of inflammation and vascular osteogenesis; and the effect of galectin-3 ablation and/or exposure to an ALE/AGE on vascular smooth muscle cell (VSMC) osteogenic differentiation. While RAGE co-localized with inflammatory cells in unstable regions with microcalcification, galectin-3 was expressed also by VSMCs, especially in macrocalcified areas, where it co-localized with alkaline phosphatase. Expression of galectin-3 and osteogenic markers was higher in macrocalcified plaques, whereas the opposite occurred for RAGE and inflammatory markers. Galectin-3-deficient VSMCs exhibited defective osteogenic differentiation, as shown by altered expression of osteogenic transcription factors and proteins, blunted activation of pro-osteoblastogenic Wnt/β-catenin signalling and proliferation, enhanced apoptosis, and disorganized mineralization. These abnormalities were associated with RAGE up-regulation, but were only in part prevented by RAGE silencing, and were partially mimicked or exacerbated by treatment with an AGE/ALE.CONCLUSION:These data indicate a novel molecular mechanism by which galectin-3 and RAGE modulate in divergent ways, not only inflammation, but also vascular osteogenesis, by modulating Wnt/β-catenin signalling, and independently of ALEs/AGEs.
Excess energy is stored as neutral lipids in lipid droplets (LDs) whose surface is coated by PAT proteins, each playing a distinct cellular function. The adipocyte differentiation-related protein (ADRP) and tail-interacting protein (TIP47) are expressed almost ubiquitously, whereas the oxidative tissue-enriched PAT protein (OXPAT) is expressed in specific tissues, such as the liver. In rat liver, only ADRP expression has been documented. This study was aimed at identifying OXPAT and TIP47 transcripts in rat hepatocytes, and investigating how their expression is modulated by excess lipids, using fat-enriched hepatocytes to mimic different degrees of steatosis. Primary rat hepatocytes were exposed to fatty acids (FFAs) for 12, 24 and 36 h. Lipid accumulation was estimated by spectrophotometric quantification of triacylglycerol. Expression of PAT proteins as well as of PPARgamma was evaluated by real-time RT-PCR. Hepatocytes exposed to FFAs showed progressive lipid accumulation. The increase in lipid content was associated with the induction of PAT protein expression. At 12 h, OXPAT and TIP47 mRNA expression was up-regulated. At longer times, the level of OXPAT transcripts remained high, whereas that of TIP47 slowly declined. Conversely, ADRP expression showed a time-dependent increase with exposure to FFAs. This study demonstrates, for the first time, the presence of OXPAT and TIP47 transcripts in rat hepatocytes, as well as their up-regulation with lipid accumulation. The distinct time courses observed for the three PAT proteins during FFA exposure might reflect the different roles played by each protein in lipid metabolism in the hepatocyte. Up-regulation of TIP47 and OXPAT might represent an early response to excess lipids, while, in correspondence with a lipid overload, up-regulation of ADRP could address lipids towards storage.
Atherosclerosis and renal disease are related conditions, sharing several risk factors. This includes hyperlipidaemia, which may result in enhanced lipoprotein accumulation and chemical modification, particularly oxidation, with formation of advanced lipoxidation endproducts (ALEs). We investigated whether increased lipid peroxidation plays a major role in the pathogenesis of lipid‐induced renal disease, via receptor‐mediated mechanisms involving the scavenger and advanced glycation endproduct (AGE) receptors. Mice knocked out for galectin‐3 ( Gal 3 −/− ), an AGE receptor previously shown to protect from AGE‐induced renal injury, and the corresponding wild‐type ( Gal 3 +/+ ) animals, were fed an atherogenic high‐fat diet (HFD; 15% fat, 1.25% cholesterol and 0.5% sodium cholate); mice fed a normal‐fat diet (NFD; 4% fat) served as controls. Gal 3 +/+ mice fed a HFD developed glomerular disease, as indicated by proteinuria, mesangial expansion and glomerular hypertrophy and sclerosis. Glomerular injury was associated with increased glomerular matrix protein expression, ALE and oxidized LDL content, oxidative stress, AGE and scavenger receptor expression and macrophage infiltration, with only modest renal/glomerular fat accumulation and changes in lipid metabolism. Fibrotic and inflammatory changes, together with accumulation of ALEs, such as 4‐hydroxy‐2‐nonenal adducts and N ε ‐carboxymethyllysine, oxidative stress and expression of the receptor of AGEs (RAGE), were significantly more marked in Gal 3 −/− animals, whereas fat deposition and abnormalities in lipid metabolism remained modest. Thus, lipid‐induced renal damage is mainly dependent on lipid peroxidation with formation of carbonyl reactive species and ALEs, which accumulate within the kidney tissue, thus triggering receptor‐mediated pro‐inflammatory signalling pathways, as in atherogenesis. Moreover, galectin‐3 exerts a significant role in the uptake and effective removal of modified lipoproteins, with diversion of these products from RAGE‐dependent pro‐inflammatory pathways associated with downregulation of RAGE expression. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
OBJECTIVETo evaluate the presence of human papillomavirus (HPV) infection, the methylation status in the promoter region of thrombospondin‐1 (TSP‐1), RAS association domain family 1A (RASSF1‐A) and p16 genes, and the expression of TSP‐1, CD31, p16 and p53 proteins in patients diagnosed with penile cancer, and the possible associations between these variables and clinical and pathological features.PATIENTS AND METHODSHPV types, gene promoter hypermethylation and protein expression were analysed by reverse line blot, methylation‐specific polymerase chain reaction, and immunohistochemistry, respectively, in 24 penile squamous cell carcinomas.RESULTSHPV infection was detected in 11 of 24 cases (46%), and TSP‐1, RASSF1‐A and p16 genes were hypermethylated in 46%, 42% and 38% of the tumours, respectively. TSP‐1 hypermethylation was associated with unfavourable histological grade (grade 3; P = 0.033), vascular invasion (P = 0.023), weak expression of TSP‐1 protein (P = 0.041), and shorter overall survival (P = 0.04). TSP‐1 expression was not associated with microvessel density. However, RASSF1‐A hypermethylation was more frequent in T1 tumours (P = 0.01), and p16 hypermethylation was not associated with any of the tested variables except for absence of p16 expression (P = 0.022).CONCLUSIONIn summary, the epigenetic inactivation of TSP‐1 and RASSF1‐A genes is associated with pathological variables and seems to be of prognostic significance in penile cancer.
Our recent studies have shown that both cigarette smoke and UV-containing light, which are the most widespread and ubiquitous mutagens and carcinogens in the world, cause systemic genotoxic damage in hairless mice. Further studies were designed with the aim of evaluating the induction of genotoxic and carcinogenic effects in Swiss albino mice exposed to smoke and/or light since birth. We observed that a 4-month whole-body exposure of mice to mainstream cigarette smoke, starting at birth, caused an early and potent carcinogenic response in the lung and other organs. Our further experiments showed that exposure of mice to environmental cigarette smoke, during the first 5 weeks of life, resulted in a variety of significant alterations of intermediate biomarkers, including cytogenetic damage in bone marrow and peripheral blood, formation of lipid peroxidation products, increase of bulky DNA adduct levels, induction of oxidative DNA damage, and overexpression of OGG1 gene in lung, stimulation of apoptosis, hyperproliferation and loss of Fhit protein in pulmonary alveolar macrophages and/or bronchial epithelial cells, and early histopathological alterations in the respiratory tract. Moreover, exposure of mice to UV-containing light, mimicking solar irradiation, significantly enhanced oxidative DNA damage and bulky DNA adduct levels in lung, and synergized with smoke in inducing molecular alterations in the respiratory tract. The baseline OGG1 expression in lung was particularly high at birth and decreased in post-weanling mice. Oxidative DNA damage and other investigated end-points exhibited differential patterns in post-weanling mice and adult mice. The findings of these studies provide a mechanistic clue to the general concept that the neonatal period and early stages of life are critical in affecting susceptibility to carcinogens.