The expression of the receptor for glycation endproducts (RAGE) in oral squamous cell carcinomas

The Post-Translational Modifications of Human Salivary Peptides and Proteins Evidenced by Top-Down Platforms

In this review, we extensively describe the main post-translational modifications that give rise to the multiple proteoforms characterized to date in the human salivary proteome and their potential role. Most of the data reported were obtained by our group in over twenty-five years of research carried out on human saliva mainly by applying a top-down strategy. In the beginning, we describe the products generated by proteolytic cleavages, which can occur before and after secretion. In this section, the most relevant families of salivary proteins are also described. Next, we report the current information concerning the human salivary phospho-proteome and the limited news available on sulfo-proteomes. Three sections are dedicated to the description of glycation and enzymatic glycosylation. Citrullination and N- and C-terminal post-translational modifications (PTMs) and miscellaneous other modifications are described in the last two sections. Results highlighting the variation in the level of some proteoforms in local or systemic pathologies are also reviewed throughout the sections of the manuscript to underline the impact and relevance of this information for the development of new diagnostic biomarkers useful in clinical practice.

The 'Danse Macabre'-Neutrophils the Interactive Partner Affecting Oral Cancer Outcomes

Over the past few decades, tremendous advances in the prevention, diagnosis, and treatment of cancer have taken place. However for head and neck cancers, including oral cancer, the overall survival rate is below 50% and they remain the seventh most common malignancy worldwide. These cancers are, commonly, aggressive, genetically complex, and difficult to treat and the delay, which often occurs between early recognition of symptoms and diagnosis, and the start of treatment of these cancers, is associated with poor prognosis. Cancer development and progression occurs in concert with alterations in the surrounding stroma, with the immune system being an essential element in this process. Despite neutrophils having major roles in the pathology of many diseases, they were thought to have little impact on cancer development and progression. Recent studies are now challenging this notion and placing neutrophils as central interactive players with other immune and tumor cells in affecting cancer pathology. This review focuses on how neutrophils and their sub-phenotypes, N1, N2, and myeloid-derived suppressor cells, both directly and indirectly affect the anti-tumor and pro-tumor immune responses. Emphasis is placed on what is currently known about the interaction of neutrophils with myeloid innate immune cells (such as dendritic cells and macrophages), innate lymphoid cells, natural killer cells, and fibroblasts to affect the tumor microenvironment and progression of oral cancer. A better understanding of this dialog will allow for improved therapeutics that concurrently target several components of the tumor microenvironment, increasing the possibility of constructive and positive outcomes for oral cancer patients. For this review, PubMed, Web of Science, and Google Scholar were searched for manuscripts using keywords and combinations thereof of "oral cancer, OSCC, neutrophils, TANs, MDSC, immune cells, head and neck cancer, and tumor microenvironment" with a focus on publications from 2018 to 2021.

RAGE in the pathophysiology of skeletal muscle

Emerging evidence suggests that the signalling of the Receptor for Advanced Glycation End products (RAGE) is critical for skeletal muscle physiology controlling both the activity of muscle precursors during skeletal muscle development and the correct time of muscle regeneration after acute injury. On the other hand, the aberrant re-expression/activity of RAGE in adult skeletal muscle is a hallmark of muscle wasting that occurs in response to ageing, genetic disorders, inflammatory conditions, cancer, and metabolic alterations. In this review, we discuss the mechanisms of action and the ligands of RAGE involved in myoblast differentiation, muscle regeneration, and muscle pathological conditions. We highlight potential therapeutic strategies for targeting RAGE to improve skeletal muscle function.

Cigarette smoke extract induces oral squamous cell carcinoma cell invasion in a receptor for advanced glycation end-products-dependent manner

Oral squamous cell carcinoma (OSCC) affects approximately 30,000 people and is associated with tobacco use. Little is known about the mechanistic effects of second-hand smoke in the development of OSSC. The receptor for advanced glycation end-products (RAGE) is a surface receptor that is upregulated by second-hand smoke and inhibited by semi-synthetic glycosaminoglycan ethers (SAGEs). Our objective was to determine the role of RAGE during cigarette smoke extract-induced cellular responses and to use SAGEs as a modulating factor of Ca9-22 OSCC cell invasion. Ca9-22 cells were cultured in the presence or absence of cigarette smoke extract and SAGEs. Cell invasion was determined and cells were lysed for western blot analysis. Ras and nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF-κB) activation were determined. Treatment of cells with cigarette smoke extract resulted in: (i) increased invasion of OSCC; (ii) increased RAGE expression; (iii) inhibition of cigarette smoke extract-induced OSCC cell invasion by SAGEs; (iv) increased Ras, increased AKT and NF-κB activation, and downregulation by SAGEs; and (v) increased expression of matrix metalloproteinases (MMPs) 2, 9, and 14, and downregulation by SAGEs. We conclude that cigarette smoke extract increases invasion of OSCC cells in a RAGE-dependent manner. Inhibition of RAGE decreases the levels of its signaling molecules, which results in blocking the cigarette smoke extract-induced invasion.

Certainty of S100 from Physiology to Pathology

S100 exists in wide variety of tissues and cell types, originally isolated from brain tissue and they are of low molecular weight proteins. S100 is evenly distributed in cytoplasm and also in nucleoplasm and is involved in both intercellular and extracellular functions. S100 protein is generally expressed in normal and also in pathological conditions. In current review, we discuss: a) update nomenclature of the various S100 proteins, b) expression of S100 in oral diseases (different soft tissue tumors, odontogenic cyst and tumor) for diagnostic value and also to know their histogenesis, c) role of S100 and RAGE receptor in oral squamous cell carcinoma.

Clinical Value of High Mobility Group Box 1 and the Receptor for Advanced Glycation End-products in Head and Neck Cancer: A Systematic Review

Introduction High mobility group box 1 is a versatile protein involved in gene transcription, extracellular signaling, and response to inflammation. Extracellularly, high mobility group box 1 binds to several receptors, notably the receptor for advanced glycation end-products. Expression of high mobility group box 1 and the receptor for advanced glycation end-products has been described in many cancers.

Objectives To systematically review the available literature using PubMed and Web of Science to evaluate the clinical value of high mobility group box 1 and the receptor for advanced glycation end-products in head and neck squamous cell carcinomas.

Data synthesis A total of eleven studies were included in this review. High mobility group box 1 overexpression is associated with poor prognosis and many clinical and pathological characteristics of head and neck squamous cell carcinomas patients. Additionally, the receptor for advanced glycation end-products demonstrates potential value as a clinical indicator of tumor angiogenesis and advanced staging. In diagnosis, high mobility group box 1 demonstrates low sensitivity.

Conclusion High mobility group box 1 and the receptor for advanced glycation end-products are associated with clinical and pathological characteristics of head and neck squamous cell carcinomas. Further investigation of the prognostic and diagnostic value of these molecules is warranted.

RAGE gene polymorphism and environmental factor in the risk of oral cancer

Oral squamous cell carcinoma is a common neoplasm that is known to be causally associated with genetic factors and environmental carcinogens. The receptor for advanced glycosylation endproducts (RAGE) is a transmembrane protein of the immunoglobulin superfamily with broad specificity for multiple ligands, and it has been shown to play vital roles in several pathophysiologic processes, including diabetes, Alzheimer disease, renal disease, cardiovascular disease, and cancer. The present study aimed to assess the influences of RAGE gene polymorphisms, combined with environmental carcinogens on the predisposition to oral tumorigenesis. Five polymorphisms of the RAGE gene-including -374T>A (rs1800624), -429T>C (rs1800625), 1704G>T (rs184003), Gly82Ser (rs2070600), and a 63-bp deletion allele (-407 to -345)-were examined from 592 controls and 618 patients with oral cancer. We found that individuals carrying the polymorphic allele of rs1800625 are more susceptible to oral cancer (odds ratio [OR], 1.899; 95% confidence interval [CI], 1.355 to 2.661; adjusted OR [AOR], 2.053; 95% CI, 1.269 to 3.345) after adjustment for age, sex, betel nut chewing, and tobacco consumption. Moreover, we observed a significant association of rs1800625 variants with late-stage tumors (stage III/IV, OR, 1.736; 95% CI, 1.126 to 2.677; AOR, 1.771; 95% CI, 1.101 to 2.851) and large-size tumors (>2 cm in the greatest dimension; OR, 1.644; 95% CI, 1.083 to 2.493; AOR, 1.728; 95% CI, 1.089 to 2.741). Based on behavioral exposure of environmental carcinogens, the presence of 4 RAGE single-nucleotide polymorphisms (SNPs), combined with betel quid chewing and/or tobacco use, greatly augmented the risk of oral cancer. In addition, carriers of particular haplotypes of the 4 RAGE SNPs examined are more prone to develop oral cancer. These results indicate an involvement of RAGE SNP rs1800625 in the development of oral squamous cell carcinoma and implicate the interaction between RAGE gene polymorphisms and environmental mutagens as a predisposing factor of oral carcinogenesis.

RAGE is essential for oncogenic KRAS-mediated hypoxic signaling in pancreatic cancer

A hypoxic tumor microenvironment is characteristic of many cancer types, including one of the most lethal, pancreatic cancer. We recently demonstrated that the receptor for advanced glycation end products (RAGE) has an important role in promoting the development of pancreatic cancer and attenuating the response to chemotherapy. We now demonstrate that binding of RAGE to oncogenic KRAS facilitates hypoxia-inducible factor 1 (HIF1)α activation and promotes pancreatic tumor growth under hypoxic conditions. Hypoxia induces NF-κB-dependent and HIF1α-independent RAGE expression in pancreatic tumor cells. Moreover, the interaction between RAGE and mutant KRAS increases under hypoxia, which in turn sustains KRAS signaling pathways (RAF-MEK-ERK and PI3K-AKT), facilitating stabilization and transcriptional activity of HIF1α. Knock down of RAGE in vitro inhibits KRAS signaling, promotes HIF1α degradation, and increases hypoxia-induced pancreatic tumor cell death. RAGE-deficient mice have impaired oncogenic KRAS-driven pancreatic tumor growth with significant downregulation of the HIF1α signaling pathway. Our results provide a novel mechanistic link between NF-κB, KRAS, and HIF1α, three potent molecular pathways in the cellular response to hypoxia during pancreatic tumor development and suggest alternatives for preventive and therapeutic strategies.

Defective RAGE activity in embryonal rhabdomyosarcoma cells results in high PAX7 levels that sustain migration and invasiveness

Rhabdomyosarcoma is a muscle-derived malignant tumor mainly affecting children. The most frequent variant, embryonal rhabdomyosarcoma (ERMS) is characterized by overexpression of the transcription factor, PAX7 which prevents ERMS cells from exiting the cell cycle and terminally differentiating. However, a role for PAX7 in the invasive properties of ERMS cells has not been investigated in detail thus far. Here we show that ectopic expression of receptor for advanced glycation end-products (RAGE) in human ERMS cells results in the activation of a RAGE/myogenin axis which downregulates PAX7 by transcriptional and post-translational mechanisms, as in normal myoblasts, and reduces metastasis formation. High PAX7 sustains migration and invasiveness in ERMS cells by upregulating EPHA3 and EFNA1 and downregulating NCAM1 thus decreasing the neural cell adhesion molecule (NCAM)/polysialylated-NCAM ratio. Microarray gene expression analysis shows that compared with the RAGE(-ve) TE671/WT cells and similarly to primary human myoblasts, TE671/RAGE cells show upregulation of genes involved in muscle differentiation and cell adhesion, and downregulation of cell migration related and major histocompatibility complex class I genes. Our data reveal a link between PAX7 and metastasis occurrence in ERMSs, and support a role for the RAGE/myogenin axis in metastasis suppression. Thus, low RAGE expression in ERMS primary tumors may be predictive of metastatic behavior.

Immunohistochemical expression of RAGE and its ligand (S100A9) in cervical lesions

Altered expressions of receptor for advanced glycation end-products (RAGE) and its ligand (S100A9) are observed in many cancers and play a key role in inflammation-associated cancer. In our previous study, by two-dimensional gel electrophoresis followed by mass spectrometry, the expression of S100A9 protein was found to increase in squamous cervical cancer compared with adjacent normal cervical tissues. Therefore, in the present study we observed the expressions of S100A9 and RAGE in 30 chronic cervicitis, 50 cervical intraepithelial neoplasia (CIN), and 40 squamous cervical cancer (SCC) using immunohistochemical analysis and analyzed the differential expression and possible role of S100A9 and RAGE in cancer development. Immunohistochemical findings were as follows: the expressions of S100A9 and RAGE were demonstrated in chronic cervicitis, CIN, and SCC. Moreover, their expressions were gradually increasing as the tumor progressed. In SCC, the staining scores of S100A9 and RAGE were significantly higher in well-differentiated tumors compared to moderately and poorly differentiated tumors. The expression of S100A9 in epithelial cells exhibited a positive correlation to RAGE expression in chronic cervicitis, CIN, and SCC. There were no significant difference of S100A9 immunoreactivity in stromal cells among chronic cervicitis, CIN, and SCC. Moreover, there was no correlation between S100A9 immunoreactivity in stromal cells of SCC and clinicopathological parameters. Finally, double immunohistochemistry illustrated that RAGE and S100A9 co-express in SCC. In conclusion, RAGE binds its ligand (S100A9), which plays an important role in the development of SCC. In addition, the expressions of S100A9 and RAGE in SCC tumor cells were closely associated with histological differentiation.

Role of the advanced glycation end products receptor in Crohn’s disease inflammation

AIM: To investigate the level of mucosal expression and the involvement of the receptor for the advanced glycation end products (RAGE) in delayed apoptosis and tumor necrosis factor (TNF)-α production in Crohn’s disease (CD).

METHODS: Surgical and endoscopic specimens from both inflamed and non-inflamed areas of the ileum and/or colon were collected from 20 and 14 adult CD patients, respectively, and used for the assessment of RAGE expression by means of immunohistochemistry and western blotting analysis. Normal tissues from 21 control subjects were used for comparison. The same polyclonal anti-human RAGE antibody (R and D System) was used in all experimental conditions. RAGE staining was quantized by a score including both the amount of positive cells and intensity of immunoreactivity; cellular pattern was also described. The effects of RAGE blocking on apoptotic rate and TNF-α production were investigated on immune cells freshly isolated from CD mucosa and incubated both with and without the muramyl dipeptide used as antigenic stimulus. Statistical analysis was performed via the test for trend, with regression models to account for intra-patient correlations. A 2-sided P < 0.05 was considered significant.

RESULTS: In inflamed areas, RAGE expression in both the epithelial and lamina propria compartments was higher than control tissues (P = 0.001 and 0.021, respectively), and a cluster of positive cells were usually found in proximity of ulcerative lesions. Similar results were obtained in the lamina propria compartment of non-inflamed areas (P = 0.025). The pattern of staining was membranous and granular cytosolic at the epithelial level, while in the lamina propria it was diffuse cytosolic. When evaluating the amount of protein expression by immunoblotting, a significant increase of both surface area and band intensity (P < 0.0001 for both) was observed in CD inflamed areas compared to control tissue, while in non-inflamed areas a significant increase was found only for band intensity (P < 0.005). Moreover, a significantly lower expression in non-inflamed areas in comparison with inflamed areas was found for both surface area and band intensity (P < 0.0006 for both). Finally, RAGE blocking largely affects both the apoptotic rate of mucosal cells (towards an increase in both non-inflamed and inflamed areas of P < 0.001 and < 0.0001, respectively) and TNF-α secretion (towards a decrease in both non-inflamed and inflamed areas of P < 0.05 and < 0.01, respectively), mainly in the presence of antigenic stimulation.

CONCLUSION: RAGE is up-regulated in CD, especially in inflamed areas, and it appears to play a role in the mechanisms involved in chronic inflammation.

Endogenous damage-associated molecular pattern molecules at the crossroads of inflammation and cancer

Inflammatory mediators play important roles in the development and progression of cancer. Cellular stress, damage, inflammation, and necrotic cell death cause release of endogenous damage-associated molecular pattern (DAMP) molecules or alarmins, which alert the host of danger by triggering immune responses and activating repair mechanisms through their interaction with pattern recognition receptors. Recent studies show that abnormal persistence of these molecules in chronic inflammation and in tumor microenvironments underlies carcinogenesis and tumor progression, indicating that DAMP molecules and their receptors could provide novel targets for therapy. This review focuses on the role of DAMP molecules high-mobility group box 1 and S100 proteins in inflammation, tumor growth, and early metastatic events.

Expression of receptor for advanced glycation end products (RAGE) is related to prognosis in patients with esophageal squamous cell carcinoma

The receptor for advanced glycation end products (RAGE), known as a multiligand receptor for certain stress-associated factors, has been considered to affect the characteristic differences of various cancer cells. We analyzed the expression and clinicopathological significance of RAGE in esophageal squamous cell carcinoma. We investigated immunohistochemically the relationship between RAGE expression and clinicopathological factors, including prognosis, in surgical specimens of primary tumors in 216 patients with esophageal squamous cell carcinoma. Prognostic factors were examined by univariate and multivariate analyses (Cox proportional hazard regression model). The positive expression rate of RAGE was 50%. RAGE expression was negatively correlated with depth of invasion and venous invasion. Moreover, tumors with positive RAGE expression exhibited better prognosis than those with negative RAGE expression (5-year survival, 52% vs. 32%, respectively). Multivariate analysis indicated that the positive expression of RAGE was an independent prognostic factor, along with tumor depth and nodal metastasis. Our findings suggest that loss of RAGE expression may play an important role in the progression of esophageal squamous cell carcinoma. Evaluation of the expression of RAGE could be useful for determining the tumor properties, including those associated with prognosis, in patients with esophageal squamous cell carcinoma.