Accumulation of the advanced glycation end product carboxymethyl lysine in breast cancer is positively associated with estrogen receptor expression and unfavorable prognosis in estrogen receptor-negative cases

Oxidative Stress in Breast Cancer: A Biochemical Map of Reactive Oxygen Species Production

This review systematizes information about the metabolic features of breast cancer directly related to oxidative stress. It has been shown those redox changes occur at all levels and affect many regulatory systems in the human body. The features of the biochemical processes occurring in breast cancer are described, ranging from nonspecific, at first glance, and strictly biochemical to hormone-induced reactions, genetic and epigenetic regulation, which allows for a broader and deeper understanding of the principles of oncogenesis, as well as maintaining the viability of cancer cells in the mammary gland. Specific pathways of the activation of oxidative stress have been studied as a response to the overproduction of stress hormones and estrogens, and specific ways to reduce its negative impact have been described. The diversity of participants that trigger redox reactions from different sides is considered more fully: glycolytic activity in breast cancer, and the nature of consumption of amino acids and metals. The role of metals in oxidative stress is discussed in detail. They can act as both co-factors and direct participants in oxidative stress, since they are either a trigger mechanism for lipid peroxidation or capable of activating signaling pathways that affect tumorigenesis. Special attention has been paid to the genetic and epigenetic regulation of breast tumors. A complex cascade of mechanisms of epigenetic regulation is explained, which made it possible to reconsider the existing opinion about the triggers and pathways for launching the oncological process, the survival of cancer cells and their ability to localize.

Dietary and serum advanced glycation end-products and clinical outcomes in breast cancer

One in five women with breast cancer will relapse despite ideal treatment. Body weight and physical activity are strongly associated with recurrence risk, thus lifestyle modification is an attractive strategy to improve prognosis. Trials of dietary modification in breast cancer are promising but the role of specific diets is unclear, as is whether high-quality diet without weight loss can impact prognosis. Advanced glycation end-products (AGEs) are compounds produced in the body during sugar metabolism. Exogenous AGEs, such as those found in food, combined with endogenous AGEs, make up the total body AGE load. AGEs deposit in tissues over time impacting cell signaling pathways and altering protein functions. AGEs can be measured or estimated in the diet and measured in blood through their metabolites. Studies demonstrate an association between AGEs and breast cancer risk and prognosis. Here, we review the clinical data on dietary and serum AGEs in breast cancer.

Comparative analysis of Nε-carboxymethyl-lysine and inflammatory markers in diabetic and non-diabetic coronary artery disease patients

BACKGROUND

Coronary artery disease (CAD) is a major cause of death worldwide, and India contributes to about one-fifth of total CAD deaths. The development of CAD has been linked to the accumulation of Nε-carboxymethyl-lysine (CML) in heart muscle, which correlates with fibrosis.

AIM

To assess the impact of CML and inflammatory markers on the biochemical and cardiovascular characteristics of CAD patients with and without diabetes.

METHODS

We enrolled 200 consecutive CAD patients who were undergoing coronary angiography and categorized them into two groups based on their serum glycosylated hemoglobin (HbA1c) levels (group I: HbA1c ≥ 6.5; group II: HbA1c < 6.5). We analyzed the levels of lipoproteins, plasma HbA1c levels, CML, interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and nitric oxide.

RESULTS

Group I (81 males and 19 females) patients had a mean age of 54.2 ± 10.2 years, with a mean diabetes duration of 4.9 ± 2.2 years. Group II (89 males and 11 females) patients had a mean age of 53.2 ± 10.3 years. Group I had more severe CAD, with a higher percentage of patients with single vessel disease and greater stenosis severity in the left anterior descending coronary artery compared to group II. Group I also exhibited a larger left atrium diameter. Group I patients exhibited significantly higher levels of CML, TNF-α, and IL-6 and lower levels of nitric oxide as compared with group II patients. Additionally, CML showed a significant positive correlation with IL-6 (r = 0.596, P = 0.001) and TNF-α (r = 0.337, P = 0.001) and a negative correlation with nitric oxide (r=-4.16, P = 0.001). Odds ratio analysis revealed that patients with CML in the third quartile (264.43-364.31 ng/mL) were significantly associated with diabetic CAD at unadjusted and adjusted levels with covariates.

CONCLUSION

CML and inflammatory markers may play a significant role in the development of CAD, particularly in diabetic individuals, and may serve as potential biomarkers for the prediction of CAD in both diabetic and non-diabetic patients.

Dietary advanced glycation end products are associated with an increased risk of breast cancer in Iranian adults

BACKGROUND

Dietary advanced glycation end products (AGEs) can play an important role in increasing inflammatory factors and oxidative stress as risk factors for cancers. In the present study, we aimed to assess the relationship between dietary AGEs and the risk of breast cancer (BC) in Iranian adult women.

METHODS

This hospital-based case-control study includes 401 participants aged ≥ 30 years old. The cases group consisted of 134 women diagnosed with histologically confirmed BC. The control group included 267 women enrolled randomly from patients admitted to the same hospitals. Dietary intake information was determined using a validated food frequency questionnaire, and dietary AGEs intake was computed for all participants. Logistic regression models, adjusted for potential confounders, were used to determine the odds ratios (OR) and 95% confidence interval (CI) of BC across tertiles of dietary AGEs.

RESULTS

The mean ± SD age and body mass index of the study population were 47.92 ± 10.33 years and 29.43 ± 5.51 kg/m2, respectively. The median (interquartile) of dietary AGEs in all individuals was 9251(7450, 11,818) kU/day. After adjusting for age, first pregnancy age, and energy intake, participants in the highest tertile of dietary AGEs intakes had higher odds of BC compared to those in the lowest tertile of dietary AGEs (OR:2.29;95%CI:1.19-4.39, Ptrend:0.012). Additionally, in the multivariable model, after adjusting for age, age at first pregnancy, energy, menopausal status, family history of cancer, anti-inflammatory drug use, Vitamin D supplementation, physical activity, body mass index, number of childbirths, and history of abortion, breastfeeding, and oral contraceptive pills use, the odds of BC were increased across tertiles of dietary AGEs intake (OR: 2.33; 95%CI: 1.18-4.60, Ptrend: 0.017).

CONCLUSION

The present findings suggest that a diet with high AGEs is associated with a higher likelihood of BC in adult women.

AGEs and RAGE: metabolic and molecular signatures of the glycation-inflammation axis in malignant or metastatic cancers

From attributing mutations to cancers with the advent of cutting-edge genetic technology in recent decades, to re-searching the age-old theory of intrinsic metabolic shift of cancers (Warburg's glycolysis), the quest for a precise panacea for mainly the metastatic cancers, remains incessant. This review delineates the advanced glycation end product (AGE)-receptor for AGE (RAGE) pathway driven intricate oncogenic cues, budding from the metabolic (glycolytic) reliance of tumour cells, branching into metastatic emergence of malignancies. Strong AGE-RAGE concomitance in metastasis, chemo-resistance and cancer resurgence adversely incite disease progression and patient mortality. At the conjunction of metabolic and metastatic shift of cancers, are the "glycolytically" generated AGEs and AGE-activated RAGE, instigating aberrant molecular pathways, culminating in aggressive malignancies. AGEs as by-products of metabolic insurgence, modify the metabolome, epigenome and microbiome, besides coercing the inter-, intra- and extra-cellular micro-milieu conducive for oncogenic events like epithelial-mesenchymal transition (EMT). AGE-RAGE synergistically elicit ATP surge for surplus energy, autophagy for apoptotic evasion and chemo-resistance, insulin-like growth factor 1 (IGF-1) for meta-inflammation and angiogenesis, high mobility group box-1 (HMGB1) for immune tolerance, S100 proteins for metastasis, and p53 protein attenuation for tumour suppression. AGEs are pronouncedly reported in invasive forms of breast, prostate, colon and pancreatic cancers, higher in patients with cancer than healthy counterparts, and higher in advanced stage than localized phase. Hence, the investigation of person-specific presence of AGEs, soluble RAGE and AGE-activated RAGE can be advocated as impending bio-markers for diagnostic, prognostic and therapeutic purposes, to predict cancer risk in patients with diabetes, obesity, metabolic syndrome as well as general population, to monitor prognosis and metastasis in patients with cancer, and to reckon complications in cancer survivors. Furthermore, clinical reports of exogenous (dietary) and endogenous (internally formed) AGEs in cancer patients, and contemporary clinical trials involving AGE-RAGE axis in cancer are underlined with theranostic implications.

Genetically Modified Circulating Levels of Advanced Glycation End-Products and Their Soluble Receptor (AGEs-RAGE Axis) with Risk and Mortality of Breast Cancer

The interaction of advanced glycation end-products (AGEs) with their receptor (RAGE) elicits oxidative stress and inflammation, which is involved in the development of breast cancer. However, large-scale population-based evidence exploring genetically modified circulating levels of AGEs-RAGE axis with risk and mortality of breast cancer is scarce. We recruited 1051 pairs of age-matched breast cancers and controls and measured plasma AGEs and sRAGE concentrations by enzyme-linked immunosorbent assay (ELISA). Multivariate logistic regression and Cox proportional hazard model were used to calculate the effects of plasma levels and genetic variants of the AGEs-RAGE axis and their combined effects on breast cancer risk and prognosis, respectively. Furthermore, linear regression was performed to assess the modifications in plasma AGEs/sRAGE levels by genetic predisposition. Higher levels of AGEs and AGEs/sRAGE-ratio were associated with an increased risk of breast cancer, but sRAGE levels were negatively associated with breast cancer risk, especially in women <60 years. We also observed a positive association between AGEs and the bad prognosis of breast cancer. Although we did not observe a significant contribution of genetic variants to breast cancer risk, rs2070600 and rs1800624 in the AGER gene were dose-dependently correlated with sRAGE levels. Further, compared to the haplotype CT at the lowest quartile of AGEs, haplotypes TT and TA were prominently associated with breast cancer risk in the highest quartile of AGEs. This study depicted a significant association between circulating levels of AGEs-RAGE axis and breast cancer risk and mortality and revealed the potential of plasma AGEs, especially coupled with AGER polymorphism as biomarkers of breast cancer.

AGE/RAGE axis regulates reversible transition to quiescent states of ALK-rearranged NSCLC and pancreatic cancer cells in monolayer cultures

Cancer recurrence due to tumor cell quiescence after therapy and long-term remission is associated with cancer-related death. Previous studies have used cell models that are unable to return to a proliferative state; thus, the transition between quiescent and proliferative states is not well understood. Here, we report monolayer cancer cell models wherein the human non-small cell lung carcinoma cell line H2228 and pancreatic cancer cell line AsPC-1 can be reversibly induced to a quiescent state under hypoxic and serum-starved (HSS) conditions. Transcriptome and metabolome dual-omics profiles of these cells were compared with those of the human lung adenocarcinoma cell line A549, which was unable to enter a quiescent state under HSS conditions. The quiescence-inducible cells had substantially lower intracellular pyruvate and ATP levels in the quiescent state than in the proliferative state, and their response to sudden demand for energy was dramatically reduced. Furthermore, in quiescence-inducible cells, the transition between quiescent and proliferative states of these cells was regulated by the balance between the proliferation-promoting Ras and Rap1 signaling and the suppressive AGE/RAGE signaling. These cell models elucidate the transition between quiescent and proliferative states, allowing the development of drug-screening systems for quiescent tumor cells.

Influence of Metastatic Bone Lesion Type and Tumor Origin on Human Vertebral Bone Architecture, Matrix Quality, and Mechanical Properties

Metastatic spine disease is incurable, causing increased vertebral fracture risk and severe patient morbidity. Here, we demonstrate that osteolytic, osteosclerotic, and mixed bone metastasis uniquely modify human vertebral bone architecture and quality, affecting vertebral strength and stiffness. Multivariable analysis showed bone metastasis type dominates vertebral strength and stiffness changes, with neither age nor gender having an independent effect. In osteolytic vertebrae, bone architecture rarefaction, lower tissue mineral content and connectivity, and accumulation of advanced glycation end-products (AGEs) affected low vertebral strength and stiffness. In osteosclerotic vertebrae, high trabecular number and thickness but low AGEs, suggesting a high degree of bone remodeling, yielded high vertebral strength. Our study found that bone metastasis from prostate and breast primary cancers differentially impacted the osteosclerotic bone microenvironment, yielding altered bone architecture and accumulation of AGEs. These findings indicate that therapeutic approaches should target the restoration of bone structural integrity. © 2022 American Society for Bone and Mineral Research (ASBMR).

Dietary Intake of Advanced Glycation End Products (AGEs) and Mortality among Individuals with Colorectal Cancer

Advanced glycation end-products (AGEs) may promote oxidative stress and inflammation and have been linked to multiple chronic diseases, including cancer. However, the association of AGEs with mortality after colorectal cancer (CRC) diagnosis has not been previously investigated. Multivariable Cox proportional hazards models were used to calculate hazard ratios and corresponding 95% confidence intervals for associations between dietary intake of AGEs with CRC-specific and all-cause mortality among 5801 participant cases diagnosed with CRC in the European Prospective Investigation into Cancer and Nutrition study between 1993 and 2013. Dietary intakes of AGEs were estimated using country-specific dietary questionnaires, linked to an AGE database, that accounted for food preparation and processing. During a median of 58 months of follow-up, 2421 cases died (1841 from CRC). Individually or combined, dietary intakes of AGEs were not associated with all-cause and CRC-specific mortality among cases. However, there was a suggestion for a positive association between AGEs and all-cause or CRC-specific mortality among CRC cases without type II diabetes (all-cause, Pinteraction = 0.05) and CRC cases with the longest follow-up between recruitment and cancer diagnosis (CRC-specific, Pinteraction = 0.003; all-cause, Pinteraction = 0.01). Our study suggests that pre-diagnostic dietary intakes of AGEs were not associated with CRC-specific or all-cause mortality among CRC patients. Further investigations using biomarkers of AGEs and stratifying by sex, diabetes status, and timing of exposure to AGEs are warranted.

Dietary Advanced Glycation End-Products and Mortality after Breast Cancer in the Women's Health Initiative

BACKGROUND

Advanced glycation end-products (AGE) are formed through nonenzymatic glycation of free amino groups in proteins or lipid. They are associated with inflammation and oxidative stress, and their accumulation in the body is implicated in chronic disease morbidity and mortality. We examined the association between postdiagnosis dietary Nε-carboxymethyl-lysine (CML)-AGE intake and mortality among women diagnosed with breast cancer.

METHODS

Postmenopausal women aged 50 to 79 years were enrolled in the Women's Health Initiative (WHI) between 1993 and 1998 and followed up until death or censoring through March 2018. We included 2,023 women diagnosed with first primary invasive breast cancer during follow-up who completed a food frequency questionnaire (FFQ) after diagnosis. Cox proportional hazards (PH) regression models estimated adjusted hazard ratios (HR) and 95% confidence intervals (CI) of association between tertiles of postdiagnosis CML-AGE intake and mortality risk from all causes, breast cancer, and cardiovascular disease.

RESULTS

After a median 15.1 years of follow-up, 630 deaths from all causes were reported (193 were breast cancer-related, and 129 were cardiovascular disease-related). Postdiagnosis CML-AGE intake was associated with all-cause (HRT3vsT1, 1.37; 95% CI, 1.09-1.74), breast cancer (HRT3vsT1, 1.49; 95% CI, 0.98-2.24), and cardiovascular disease (HRT3vsT1, 1.91; 95% CI, 1.09-3.32) mortality.

CONCLUSIONS

Higher intake of AGEs was associated with higher risk of major causes of mortality among postmenopausal women diagnosed with breast cancer.

IMPACT

Our findings suggest that dietary AGEs may contribute to the risk of mortality after breast cancer diagnosis. Further prospective studies examining dietary AGEs in breast cancer outcomes and intervention studies targeting dietary AGE reduction are needed to confirm our findings.

Redox changes in obesity, metabolic syndrome, and diabetes

"Life is an instantaneous encounter of circulating matter and flowing energy" (Jean Giaja, Serbian physiologist), is one of the most elegant definitions not only of life but the relationship of redox biology and metabolism. Their evolutionary liaison has created inseparable yet dynamic homeostasis in health, which, when disrupted, leads to disease. This interconnection is even more pertinent today, in an era of increasing metabolic diseases of epidemic proportions such as obesity, metabolic syndrome, and diabetes. Despite great advances in understanding the molecular mechanisms of redox and metabolic regulation, we face significant challenges in preventing, diagnosing, and treating metabolic diseases. The etiological association and temporal overlap of these syndromes present significant challenges for the discrimination of appropriate clinical biomarkers for diagnosis, treatment, and outcome prediction. These multifactorial, multiorgan metabolic syndromes with complex etiopathogenic mechanisms are accompanied by disturbed redox equilibrium in target tissues and circulation. Free radicals and reactive species are considered both a causal factor and a consequence of disease status. Thus, determining the subtypes and levels of free radicals and reactive species, oxidatively damaged biomolecules (lipids, proteins, and nucleic acids) and antioxidant defense components as well as redox-sensitive transcription factors and fluxes of redox-dependent metabolic pathways will help define existing and establish novel redox biomarkers for stratifying metabolic diseases. This review aims to discuss diverse redox/metabolic aspects in obesity, metabolic syndrome, and diabetes, with the imperative to help establish a platform for emerging and future redox-metabolic biomarkers research in precision medicine. Future research warrants detailed investigations into the status of redox biomarkers in healthy subjects and patients, including the use of emerging 'omic' profiling technologies (e.g., redox proteomes, lipidomes, metabolomes, and transcriptomes), taking into account the influence of lifestyle (diet, physical activity, sleep, work patterns) as well as circadian ~24h fluctuations in circulatory factors and metabolites.

Role of Glycated High Mobility Group Box-1 in Gastric Cancer

Advanced glycation end products (AGEs) are produced in response to a high-glucose environment and oxidative stress and exacerbate various diseases. Nε-(Carboxymethyl)lysine (CML) is an AGE that is produced by the glycation of lysine residues of proteins. There are a few reports on alterations in protein function due to CML modification; however, its association with cancer is not clear. We investigated the significance of CML modification in high mobility group box protein-1 (HMGB1), a cytokine that is significantly associated with cancer progression. Treatment of the gastric cancer cell lines TMK1 and MKN74 with glyoxal or glucose resulted in increased CML modification compared to untreated cells. CML-HMGB1 was modified via oxidation and more pronouncedly activated the receptor for AGE and downstream AKT and NF-κB compared to naïve HMGB1 and oxidized HMGB1. CML-HMGB1 bound with reduced affinity to DNA and histone H3, resulting in enhanced extranuclear translocation and extracellular secretion. Treatment of gastric cancer cells with CML-HMGB1 enhanced cell proliferation and invasion, sphere formation, and protection from thapsigargin-induced apoptosis, and decreased 5-FU sensitivity in comparison to HMGB1. Further, CML-HMGB1 was detected at various levels in all the 10 gastric cancer tumor specimens. HMGB1 levels correlated with primary tumor progression and distant metastasis, whereas CML-HMGB1 levels were associated with primary tumor progression, lymph node metastasis, distant metastasis, and stage. In addition, CML-HMGB1 levels correlated with oxidative stress in cancer tissues and resistance to neoadjuvant therapy. Therefore, CML modification of HMGB1 enhanced the cancer-promoting effect of HMGB1. In this study, CML-HMGB1 has been highlighted as a new therapeutic target, and analysis of the molecular structure of CML-HMGB1 is desired in the future.

Recent Advances in Histone Glycation: Emerging role in Diabetes and Cancer

Ever increasing information on genome and proteome has offered fascinating details and new opportunities to understand the molecular biology. It is now known that histone proteins surrounding the DNA play a crucial role in the chromatin structure and function. Histones undergo a plethora of post-translational enzymatic modifications that influence nucleosome dynamics and affect DNA activity. Earlier research offered insights into the enzymatic modifications of histones; however attention has been diverted to histone modifications induced by by-products of metabolism without enzymatic engagement in the last decade. Non enzymatic modifications of histones are believed to be crucial for epigenetic landscape, cellular fate and for role in human diseases. Glycation of histone proteins constitutes the major non enzymatic modifications of nuclear proteins that have implications in diabetes and cancer. It has emerged that glycation damages nuclear proteins, modifies amino acids of histones at crucial locations, generates adducts affecting histone chromatin interaction, develops neo-epitopes inducing specific immune response and impacts cell function. Presence of circulating antibodies against glycated histone proteins in diabetes and cancer has shown immunological implications with diagnostic relevance. These crucial details make histone glycation an attractive focus for investigators. This review article, therefore, makes an attempt to exclusively summarize the recent researches in histone glycation, its impact on structural integrity of chromatin and elaborates on their role in diabetes and cancer. The work offers insights for future scientists who investigate the link between metabolism, bio-molecular structures, glycobiology, histone-DNA interactions in relation to diseases in humans.

Biomechanical Properties of Metastatically Involved Osteolytic Bone

PURPOSE OF REVIEW

Skeletal metastasis involves the uncoupling of physiologic bone remodeling resulting in abnormal bone turnover and radical changes in bony architecture, density, and quality. Bone strength assessment and fracture risk prediction are critical in clinical treatment decision-making. This review focuses on bone tissue and structural mechanisms altered by osteolytic metastasis and the resulting changes to its material and mechanical behavior.

RECENT FINDINGS

Both organic and mineral phases of bone tissue are altered by osteolytic metastatic disease, with diminished bone quality evident at multiple length-scales. The mechanical performance of bone with osteolytic lesions is influenced by a combination of tissue-level and structural changes. This review considers the effects of osteolytic metastasis on bone biomechanics demonstrating its negative impact at tissue and structural levels. Future studies need to assess the cumulative impact of cancer treatments on metastatically involved bone quality, and its utility in directing multimodal treatment planning.

The effects of metastatic lesion on the structural determinants of bone: Current clinical and experimental approaches

Metastatic bone disease is incurable with an associated increase in skeletal-related events, particularly a 17-50% risk of pathologic fractures. Current surgical and oncological treatments are palliative, do not reduce overall mortality, and therefore optimal management of adults at risk of pathologic fractures presents an unmet medical need. Plain radiography lacks specificity and may result in unnecessary prophylactic fixation. Radionuclide imaging techniques primarily supply information on the metabolic activity of the tumor or the bone itself. Magnetic resonance imaging and computed tomography provide excellent anatomical and structural information but do not quantitatively assess bone matrix. Research has now shifted to developing unbiased data-driven tools that can predict risk of impending fractures and guide individualized treatment decisions. This review discusses the state-of-the-art in clinical and experimental approaches for prediction of pathologic fractures with bone metastases. Alterations in bone matrix quality are associated with an age-related increase in skeletal fragility but the impact of metastases on the intrinsic material properties of bone is unclear. Engineering-based analyses are non-invasive with the capability to evaluate oncological treatments and predict failure due to the progression of metastasis. The combination of these approaches may improve our understanding of the underlying deterioration in mechanical performance.

Reprogramming of Mesothelial-Mesenchymal Transition in Chronic Peritoneal Diseases by Estrogen Receptor Modulation and TGF-β1 Inhibition

In chronic peritoneal diseases, mesothelial-mesenchymal transition is determined by cues from the extracellular environment rather than just the cellular genome. The transformation of peritoneal mesothelial cells and other host cells into myofibroblasts is mediated by cell membrane receptors, Transforming Growth Factor β1 (TGF-β1), Src and Hypoxia-inducible factor (HIF). This article provides a narrative review of the reprogramming of mesothelial mesenchymal transition in chronic peritoneal diseases, drawing on the similarities in pathophysiology between encapsulating peritoneal sclerosis and peritoneal metastasis, with a particular focus on TGF-β1 signaling and estrogen receptor modulators. Estrogen receptors act at the cell membrane/cytosol as tyrosine kinases that can phosphorylate Src, in a similar way to other receptor tyrosine kinases; or can activate the estrogen response element via nuclear translocation. Tamoxifen can modulate estrogen membrane receptors, and has been shown to be a potent inhibitor of mesothelial-mesenchymal transition (MMT), peritoneal mesothelial cell migration, stromal fibrosis, and neoangiogenesis in the treatment of encapsulating peritoneal sclerosis, with a known side effect and safety profile. The ability of tamoxifen to inhibit the transduction pathways of TGF-β1 and HIF and achieve a quiescent peritoneal stroma makes it a potential candidate for use in cancer treatments. This is relevant to tumors that spread to the peritoneum, particularly those with mesenchymal phenotypes, such as colorectal CMS4 and MSS/EMT gastric cancers, and pancreatic cancer with its desmoplastic stroma. Morphological changes observed during mesothelial mesenchymal transition can be treated with estrogen receptor modulation and TGF-β1 inhibition, which may enable the regression of encapsulating peritoneal sclerosis and peritoneal metastasis.

Dietary Advanced Glycation End-products (AGE) and Risk of Breast Cancer in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO)

Advanced glycation end-products (AGEs) are implicated in the pathogenesis of several chronic diseases including cancer. AGEs are produced endogenously but can also be consumed from foods. AGE formation in food is accelerated during cooking at high temperatures. Certain high fat or highly processed foods have high AGE values. The objective of the study was to assign and quantify N^ϵ-carboxymethyl-lysine (CML)-AGE content in food and investigate the association between dietary AGE intake and breast cancer risk in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. The study included women enrolled in the intervention arm who were cancer-free at baseline and completed a baseline questionnaire and food frequency questionnaire (DQX). CML-AGE values were assigned and quantified to foods in the DQX using a published AGE database. Cox proportional hazards models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) of breast cancer among all women, and stratified by race/ethnicity, invasiveness of disease, and hormone receptor status. After a median 11.5 years of follow-up, 1,592 women were diagnosed with breast cancer. Higher CML-AGE intake was associated with increased risk of breast cancer among all women (HR_Q5VSQ1, 1.30; 95% CI, 1.04-1.62; P _trend = 0.04) and in non-Hispanic white women (HR_T3VST1, 1.21; 95% CI, 1.02-1.44). Increased CML-AGE intake was associated with increased risk of in situ (HR_T3VST1, 1.49; 95% CI, 1.11-2.01) and hormone receptor-positive (HR_T3VST1, 1.24; 95% CI, 1.01-1.53) breast cancers. In conclusion, high intake of dietary AGE may contribute to increased breast cancer.

Factors associated with obesity alter matrix remodeling in breast cancer tissues

Obesity is associated with a higher risk of developing breast cancer and with worse disease outcomes for women of all ages. The composition, density, and organization of the breast tissue stroma are also known to play an important role in the development and progression of the disease. However, the connections between obesity and stromal remodeling are not well understood. We sought to characterize detailed organization features of the collagen matrix within healthy and cancerous breast tissues acquired from mice exposed to either a normal or high fat (obesity inducing) diet. We performed second-harmonic generation and spectral two-photon excited fluorescence imaging, and we extracted the level of collagen-associated fluorescence (CAF) along with metrics of collagen content, three-dimensional, and two-dimensional organization. There were significant differences in the CAF intensity and overall collagen organization between normal and tumor tissues; however, obesity-enhanced changes in these metrics, especially when three-dimensional organization metrics were considered. Thus, our studies indicate that obesity impacts significantly collagen organization and structure and the related pathways of communication may be important future therapeutic targets.

Site-specific chemoproteomic profiling of targets of glyoxal

Aim: Advanced glycation end products (AGE) are the biomarkers of aging and diabetes which are formed via reactions between glycating agents and biomacromolecules. However, no proteomic study has been reported to systematically investigate the protein substrates of AGEs. Results: In this paper, we used an aniline-based probe to capture the glyoxal-imine intermediate which is the transition sate of glyoxal-derived AGEs. Combined with the tandem orthogonal proteolysis activity-based protein profiling strategy, we successfully identified 962 lysines modified by glyoxal. Conclusion: Enzymes in glycolysis are heavily modified by glyoxal and our biochemical experiments showed that glyoxal can significantly inhibit the activity of GAPDH and glycolysis. These data indicated that AGEs modifications may contribute to pathological processes through impairing the glycolytic process.

Studies on mechanism of free Nε-(carboxymethyl)lysine-induced toxic injury in mice

Nε-(carboxymethyl)lysine (CML), which is a compound produced when food is processed, has aroused concern in recent years because of its potentially dangerous effects. This study aimed to investigate the mechanism of free CML-induced toxic injury in mice. The inflammatory cytokine tumor necrosis factor-α, transforming growth factor-β, vascular cell adhesion molecule-1 mRNA expression levels of CML-infected mice liver and kidney tissues significantly increased. While CML receptor-receptor for advanced glycation end products (RAGE) protein expression in male mice liver tissue had a more significant change than the control group, there was no significant difference in other dose groups compared with the control group. In conclusion, the foodborne free CML can be induced by oxidative stress and immune response to liver and kidney tissue injury in mice. Additionally, the free CML may also bind to RAGE, which activates the downstream inflammatory pathway.

Advanced Glycation End Products (AGEs), Glutathione and Breast Cancer: Factors, Mechanism and Therapeutic Interventions

Background:

Advanced Glycation End products (AGEs) are basically the end result of glycation of proteins and/or lipids in the presence of sugars. Specific cases of hyperglycemia have been reported with increased propensity of generation of AGEs. Many chronic and deadly diseases such as diabetes, cancer and neurodegenerative disorders have been known to be caused as a result of generation of AGEs. The role of glutathione (GSH) metabolism and its intricate association with AGEs have also been well established in breast cancer prognosis and treatment. To understand the etiology, mechanism and production of AGEs along with clinical relevance of Receptors for Advanced Glycation End-products (RAGE) and RAGE ligands, their interplay with GSH is of paramount importance especially in relation to breast cancer.

Methods:

The available literature using PubMed, National Library of Medicine database, Web of Science and SCOPUS indexed, Science Direct and other prestigious journals have been systematically reviewed using the keywords: advanced glycation end-products, breast cancer, glutathione RAGE, and AGEs inhibitors. This narrative review of all the relevant papers with significant citations has led us to have greater insight into the action mechanism and potential therapeutic significance of AGEs inhibitors.

Results:

Targeting breast cancer with the specific immunoglobulins and with other therapeutic interventions is needed to inhibit the generation of AGEs and manage glutathione expression, thus having strong implications in the management of breast cancer. Many RAGE ligands such as HMGB1, S100P, S100A8, S100A9 etc. have been known to enhance RAGE expression which may further lead to increased proliferation, migration and metastatic nature of tumor cells. Hence, RAGE and RAGE ligands in a close linkup with GSH may prove to be effective therapeutic markers of severity of breast cancer and for angiogenesis of tumor.

Conclusion:

This review provides a strong platform to comprehend the etiology, mechanism and production of AGEs and glutathione along with the agents which can block their production, paving a way for the therapeutic intervention and an amicable solution to treat and manage breast cancer.

Multimodal imaging of the receptor for advanced glycation end-products with molecularly targeted nanoparticles

The receptor for advanced glycation end-products (RAGE) is central to multiple disease states, including diabetes-related conditions such as peripheral arterial disease (PAD). Despite RAGE's importance in these pathologies, there remains a need for a molecular imaging agent that can accurately assess RAGE levels in vivo. Therefore, we have developed a multimodal nanoparticle-based imaging agent targeted at RAGE with the well-characterized RAGE ligand, carboxymethyllysine (CML)-modified human serum albumin (HSA).

Methods: A multimodal tracer (⁶⁴Cu-Rho-G4-CML) was developed using a generation-4 (G4) polyamidoamine (PAMAM) dendrimer, conjugated with both rhodamine and copper-64 (⁶⁴Cu) chelator (NOTA) for optical and PET imaging, respectively. First, ⁶⁴Cu-Rho-G4-CML and its non-targeted analogue (⁶⁴Cu-Rho-G4-HSA) were evaluated chemically using techniques such as dynamic light scattering (DLS), electron microscopy and nuclear magnetic resonance (NMR). The tracers' binding capabilities were examined at the cellular level and optimized using live and fixed HUVEC cells grown in 5.5-30 mM glucose, followed by in vivo PET-CT imaging, where the probes' kinetics, biodistribution, and RAGE targeting properties were examined in a murine model of hindlimb ischemia. Finally, histological assessment of RAGE levels in both ischemic and non-ischemic tissues was performed.

Conclusions: Our RAGE-targeted probe demonstrated an average size of 450 nm, a Kd of 340-390 nM, rapid blood clearance, and a 3.4 times greater PET uptake in ischemic RAGE-expressing hindlimbs than their non-ischemic counterpart. We successfully demonstrated increased RAGE expression in a murine model of hindlimb ischemia and the feasibility for non-invasive examination of cellular, tissue, and whole-body RAGE levels with a molecularly targeted tracer.

Extracellular matrix glycation and receptor for advanced glycation end-products activation: a missing piece in the puzzle of the association between diabetes and cancer

A growing body of epidemiologic evidence suggests that people with diabetes are at a significantly higher risk of many forms of cancer. However, the molecular mechanisms underlying this association are not fully understood. Cancer cells are surrounded by a complex milieu, also known as tumor microenvironment, which contributes to the development and metastasis of tumors. Of note, one of the major components of this niche is the extracellular matrix (ECM), which becomes highly disorganized during neoplastic progression, thereby stimulating cancer cell transformation, growth and spread. One of the consequences of chronic hyperglycemia, the most frequently observed sign of diabetes and the etiological source of diabetes complications, is the irreversible glycation and oxidation of proteins and lipids leading to the formation of the advanced glycation end-products (AGEs). These compounds may covalently crosslink and biochemically modify structure and functions of many proteins, and AGEs accumulation is particularly high in long-living proteins with low biological turnover, features that are shared by most, if not all, ECM proteins. AGEs-modified proteins are recognized by AGE-binding proteins, and thus glycated ECM components have the potential to trigger Receptor for advanced glycation end-products-dependent mechanisms. The biological consequence of receptor for advanced glycation end-products activation mechanisms seems to be connected, in different ways, to drive some hallmarks of cancer onset and tumor growth. The present review intends to highlight the potential impact of ECM glycation on tumor progression by triggering receptor for advanced glycation end-products-mediated mechanisms.

Dietary Factors and Female Breast Cancer Risk: A Prospective Cohort Study

Breast cancer is the leading cause of cancer in females and has become a major global health priority. This prospective cohort study investigated the association of dietary factors, including food items and dietary habits, with the risk of breast cancer in Korean women. Study participants were women aged 30 years or older, recruited from the National Cancer Center in South Korea between August 2002 and May 2007. They were followed until December 2014 using the Korea Central Cancer Registry to identify breast cancer cases. Among 5046 non-pre-diagnosed cancer participants, 72 breast cancer cases were prospectively identified. Participants with breast cancer had a significantly higher educational level (college or higher: 58.3% vs. 39.5%, p = 0.01), were more likely to have ever smoked (22.2% vs. 7.8%, p < 0.001), and were more likely to have a history of benign breast tumors (10% vs. 4%, p = 0.02) than non-cases. Consumption of grilled meat conferred a significantly higher risk of breast cancer in all women (hazard ratio (HR) 1.77, 95% confidence interval (CI) 1.09–2.85) and in postmenopausal women (HR 3.06, 95% CI 1.31–7.15). High-cholesterol food intake was associated with a higher risk in all women (HR 1.69, 95% CI 1.01–2.82). Irregular meal intake was associated with an elevated risk in all women (HR 2.19, 95% CI 1.20–3.98, p for trend = 0.01) and in premenopausal women (HR 2.35, 95% CI 1.13–4.91, p for trend = 0.03). Our findings suggest that grilled meat and high-cholesterol food intake and irregular eating habits may be associated with a higher risk of breast cancer. Further studies with longer follow-up periods that include information on portion size, hormone receptor status, carcinogen levels in grilled meat, and a classification of foods by source are required.