Objectives PRAME (Preferentially Expressed Antigen in Melanoma) is a tumor-associated antigen recognized by immunocytes, and it induces cytotoxic T cell-mediated responses in melanoma. PRAME expression in tumors interferes with retinoic acid receptor (RAR) signaling thus promoting tumor progression. Here, we study PRAME expression in head and neck squamous cell carcinoma (HNSCC) to determine its potential clinical significance. Materials and Methods PRAME expression in HNSCC was evaluated by immunohistochemistry in tissue microarrays of primary tumors (n=53), metastatic lymph nodes (n=8) and normal oral mucosa (n=11). Biopsies of dysplastic oral lesions (n=12) were also examined. PRAME expression levels in tissues were correlated with markers of poor prognosis in HNSCC. PRAME mRNA in HNSCC cell lines and in normal immortalized human keratinocytes (HaCaT cell line) was measured by qRT-PCR, and the protein expression by flow cytometry and western blots. Results PRAME was expressed in HNSCC cell lines and HNSCC lesions. PRAME expression in dysplastic mucosa was variable. No or only weak expression was found in normal cells or tissues. PRAME expression levels significantly correlated with the tumor grade, size, nodal involvement and the clinical status of HNSCC patients. Conclusions Elevated PRAME expression associates with clinicopathologic markers of poor outcome in HNSCC and might identify potential candidates with pre-cancerous lesions for chemoprevention with retinoids.

The work presented in this study provides the hypothesis that airway bitter T2Rs are an innovative sphere of human respiratory innate protection. TAS2R38 polymorphism may influence the susceptibility to CRS. The AVI haplotypes are an independent risk factors for CRS. Additionally, the bitter taste receptors and related signalling pathways might create an unique group of therapeutic targets to treat CRS.

A receptor for advanced glycation end products (RAGE) and its ligand high mobility group box 1 (HMGB1) protein has been linked to several chronic diseases, and acts as a trigger for inflammation signaling. Here, we study RAGE and HMGB1 expression in chronic, recalcitrant rhinosinusitis with nasal polyps (CRSwNP) to determine its potential clinical significance, i.e., disease recurrence and severity. RAGE and HMGB1 expression in CRSwNP was evaluated by immunohistochemistry in epithelial cells of fresh sinonasal mucosa samples obtained from the patients diagnosed with recalcitrant CRSwNP (n = 25) and normal control mucosa (NC) (n = 26). RAGE and HMGB1 expression levels in tissues were correlated with disease severity assessed by nasal endoscopy, CT scan, number of previous sinus surgeries, allergy status and nasosinusal microbiology. RAGE and HMGB1 were moderately or strongly expressed in CRSwNP tissue. No or weak RAGE expression was found in NC. HMGB1 was equally strongly expressed in NC. We observed a strong correlation between RAGE and disease severity, recurrence, undergone operations, asthma and aspirin exacerbated respiratory disease (AERD). Elevated RAGE expression is associated with increased disease severity, as well as allergy and AERD in patients with recalcitrant CRSwNP. It is possible that the explanation for recurrent CRSwNP pathogenesis might be related to RAGE overexpression with subsequent sinus mucosa hyperproliferation, necessitating several operations.

Cholesteatoma represents progressive expansion of the keratinizing squamous epithelium in the middle ear with subsequent chronic inflammation in subepithelial connective tissues. The hypothesis was tested that receptor for advanced glycation endproduct (RAGE) and its ligand, high-mobility box 1 (HMGB1), are overexpressed in cholesteatoma, and the RAGE/HMGB1 axis might contribute to its pathogenesis. Cholesteatoma samples (n = 36) and 27 normal skin specimens were studied by immunohistochemistry (IHC) for HMGB1 and RAGE expression. Effects of HMGB1 signaling on proliferation, migration, cytokine production, and apoptosis of human immortalized keratinocytes (HaCaTs) and normal keratinocytes were studied by quantitative reverse transcription (qRT)-PCR, IHC, Western blots, and flow cytometry after cell co-incubation with HMGB1. While all studied tissues expressed HMGB1, its expression was higher in cholesteatoma than in normal skin (p < 0.0001). All cases of cholesteatoma also showed elevated RAGE expression levels, and only 7/27 (26 %) of normal skin specimens were weakly positive for RAGE. Proliferation and migration of HaCaT cells incubated with HMGB1 were up-regulated (p < 0.05). HMGB1 also prevented HaCaT cell apoptosis and induced activation of several molecular signaling pathways in keratinocytes. The data suggest that in cholesteatoma, HMGB1 released from stressed or necrotic epithelial cells and binding to RAGE overexpressed in keratinocytes initiates molecular signaling that culminates in pro-inflammatory cytokine release and chronic inflammation.Key messageHMGB1 signaling engages multiple activation pathways in RAGE-positive keratinocytes.HMGB1 protects RAGE-positive keratinocytes from drug-induced apoptosis.Keratinocyte proliferation is controlled via RAGE and HMGB1 molecular signaling.Molecular signaling of the HMGB1/RAGE axis contributes to cholesteatoma pathogenesis.Electronic supplementary materialThe online version of this article (doi:10.1007/s00109-014-1217-3) contains supplementary material, which is available to authorized users.

Introduction. Chronic rhinosinusitis (CRS) affects 14% of the world population. The high motility group box 1 (HMGB1) protein triggers inflammation, cell proliferation and cell survival through its receptor for advanced glycation end products (RAGE) upon release from stressed or necrotic cells. The aim of the study was to analyze the expression and function of HMGB1 and RAGE in CRS, providing more information about HMGB1 signaling pathway in CRS, to determine its potential clinical significance. Material and methods. Thirty-seven patients with CRS and 26 normal controls (NC) were enrolled in this study. Classification of disease severity using the SNOT-20 questionnaire, nasal endoscopy, CT scan, assessment of allergy status, microbiological and cytological analysis was performed in patients. Fresh sinus mucosa samples were obtained and analyzed by immunohistochemistry for HMGB1 and RAGE expression in epithelial cells. ELISA assay was performed to evaluate the concentration of HMGB1 in the patients' sera. Results. No differences were found in HMGB1 immunoexpression between CRS patients and NC, however there was a highly significant difference in RAGE immunoexpression between both groups. There was a correlation between RAGE expression and number of tissue-infiltrating lymphocytes. Further, RAGE expression positively correlated with disease severity and a positive history for allergies. Conclusions. Interaction of HMGB1 and RAGE might be relevant to CRS pathomechanisms leading to sinus mucosa hyperproliferation. CRS pathogenesis might be especially related to the RAGE overexpression correlated with disease severity and allergy.