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Failure of immunotherapy in head and neck squamous cell carcinoma (HNSCC) patients represents an unmet need to augment leverage of adaptive immunity. Immunogenic cancer-testis antigen (CTA) expression as well as lymphocyte differentiation and function are regulated by DNA methylation. Therefore, epigenetic therapy via inhibition of DNA-Methyltransferases by 5-Aza-2′-deoxycytidine (DAC) serves a promising adjuvant in immunotherapy.We investigated the effects of DAC on CTA expression and proliferative capacity in HNSCC cell lines and on the expression of 12 immune checkpoint molecules (ICM) on lymphocytes of oropharyngeal squamous cell carcinoma (OPSCC) patients and healthy donors.In all cell lines CTA were upregulated accompanied by decreased proliferation. In lymphocytes pronounced alterations of the ICM repertoire were observed, influenced by donor type and subpopulation. On CD39+ CD4 and CD8 T cells, the expression of co-stimulatory ICM GITR and OX40 increased dose dependently, whereas expression decreased on CD39- CD4 T cells. PD1 expression increased primarily on CD39+ CD8 T cells and decreased on CD39- CD4 T cells. CD27 expression decreased primarily in CD8 T cells, but increased in CD39- CD4 T cells, whereas ICOS expression was lowered in both CD39+ and CD39- subsets of CD4 as well as CD8 T cells.DAC treatment increased immunogenicity and decreased proliferation in HNSCC cells while enhancing expression of co-stimulatory ICM GITR and OX40. We propose low dose DAC treatment as a adjuvant to immunotherapy.

Background: Head and neck squamous cell carcinomas (HNSCC) lack tumor-specific biomarkers. Exosomes from HNSCC patients carry immunomodulatory molecules, and correlate with clinical parameters. We compared miRNA profiles of plasma- and saliva-derived exosomes to reveal liquid biomarker candidates for HNSCC.Methods: Exosomes were isolated by differential ultracentrifugation from corresponding plasma and saliva samples from 11 HNSCC patients and five healthy donors (HD). Exosomal miRNA profiles, as determined by nCounter® SPRINT technology, were analyzed regarding their diagnostic and prognostic potential, correlated to clinical data and integrated into network analysis.Results: 119 miRNAs overlapped between plasma- and saliva-derived exosomes of HNSCC patients, from which 29 tumor-exclusive miRNAs, associated with TP53, TGFB1, PRDM1, FOX O 1 and CDH1 signaling, were selected. By intra-correlation of tumor-exclusive miRNAs from plasma and saliva, top 10 miRNA candidates with the strongest correlation emerged as diagnostic panels to discriminate cancer and healthy as well as potentially prognostic panels for disease-free survival (DFS). Further, exosomal miRNAs were differentially represented in human papillomavirus (HPV) positive and negative as well as low and high stage disease.Conclusion: A plasma- and a saliva-derived panel of tumor-exclusive exosomal miRNAs hold great potential as liquid biopsy for discrimination between cancer and healthy as well as HPV status and disease stage. Exosomal miRNAs from both biofluids represent a promising tool for future biomarker studies, emphasizing the possibility to substitute plasma by less-invasive saliva collection.

BackgroundExosomes contribute to immunosuppression in head and neck squamous cell carcinoma (HNSCC), a tumor entity which lacks specific tumor biomarkers. Plasma-derived exosomes from HNSCC patients correlate with clinical parameters and have potential as liquid biopsy. Here, we investigate the cargo and functional profile of saliva-derived exosomes from HNSCC patients and their potential as non-invasive biomarkers for disease detection and immunomodulation.MethodsExosomes were isolated from saliva of HNSCC patients (n = 21) and healthy donors (HD, n = 12) by differential ultracentrifugation. Surface values of immune checkpoints and tumor associated antigens on saliva-derived exosomes were analyzed by bead-based flow cytometry using CD63 capture. Upon co-incubation with saliva-derived exosomes, activity and proliferation of T cells were assessed by flow cytometry (CD69 expression, CFSE assay). Adenosine levels were measured by mass spectrometry after incubation of saliva-derived exosomes with exogenous ATP. miRNA profiling of saliva-derived exosomes was performed using the nCounter® SPRINT system.ResultsSaliva-derived, CD63-captured exosomes from HNSCC patients carried high amounts of CD44v3, PDL1 and CD39. Compared to plasma, saliva was rich in tumor-derived, CD44v3+ exosomes and poor in hematopoietic cell-derived, CD45+ exosomes. CD8+ T cell activity was attenuated by saliva-derived exosomes from HNSCC patients, while proliferation of CD4+ T cells was not affected. Further, saliva-derived exosomes produced high levels of immunosuppressive adenosine. 62 HD- and 31 HNSCC-exclusive miRNAs were identified. Samples were grouped in “Healthy” and “Cancer” based on their saliva-derived exosomal miRNA profile, which was further found to be involved in RAS/MAPK, NF-κB complex, Smad2/3, and IFN-α signaling.ConclusionsSaliva-derived exosomes from HNSCC patients were enriched in tumor-derived exosomes whose cargo and functional profile reflected an immunosuppressive TME. Surface values of CD44v3, PDL1 and CD39 on CD63-captured exosomes, adenosine production and the miRNA cargo of saliva-derived exosomes emerged as discriminators of disease and emphasized their potential as liquid biomarkers specific for HNSCC.

The transcriptional co-activator BOB.1/OBF.1 is expressed in both B and T cells. The main characteristic of conventional BOB.1/OBF.1 deficient mice is the complete absence of germinal centers (GCs). This defect was mainly attributed to the defective B cell compartment. However, it is unknown whether and how BOB.1/OBF.1 expression in T cells contributes to the GC reaction. To finally clarify this question, we studied the in vivo function of BOB.1/OBF.1 in CD4+ T and follicular T helper (TFH) cell subpopulations by conditional mutagenesis, in the presence of immunocompetent B lymphocytes. BOB.1/OBF.1 deletion in CD4+ T as well as TFH cells resulted in impaired GC formation demonstrating that the impaired GC reaction described for conventional BOB.1/OBF.1-deficient mice cannot exclusively be traced back to the B cell compartment. Furthermore, we show a requirement of BOB.1/OBF.1 for T helper (TH) cell subsets, particularly for TFH cell differentiation.

Introduction: Bioflavonoids delphinidin (2-(3,4,5-Trihydroxyphenyl)chromenylium-3,5,7-triol) and luteolin (2-(3,4-Dihydroxyphenyl)-5,7-dihydroxy-4-chromenone) have been recognized as promising antioxidants and anticancer substances. Due to their extensive use, the goal of the research was to determine whether they have any genotoxic potential in vitro. Methods: Analysis of genotoxic potential was performed applying chromosome aberrations test in human lymphocyte culture, as this kind of research was not conducted abundantly for these two bioflavonoids. Delphinidin and luteolin were dissolved in DMSO and added to cultures in final concentrations of 25, 50 and 100 μM. Results: In human lymphocytes cultures Delphinidin induced PCDs in all treatments, potentially affecting the cell cycle and topoisomerase II activity. In concentration of 50 μM luteolin showed strong genotoxic effects and caused significant reduction of cell proliferation. Conclusion: Luteolin exhibited certain genotoxic and cytostatic potential. Delphinidin was not considered genotoxic, however its impact on mitosis, especially topoisomerase II activity, was revealed.

IntroductionThe human leukocyte antigen complex (HLA) is essential for inducing specific immune responses to cancer by presenting tumor-associated peptides (TAP) to T cells. Overexpressed tumor associated antigens, mainly cancer-testis antigens (CTA), are outlined as essential targets for immunotherapy in oropharyngeal squamous cell carcinoma (OPSCC). This study assessed the degree to which presentation, gene expression, and antibody response (AR) of TAP, mainly CTA, are correlated in OPSCC patients to evaluate their potential as immunotherapy targets.Materials and methodsSnap-frozen tumor (NLigand/RNA=40), healthy mucosa (NRNA=6), and healthy tonsils (NLigand=5) samples were obtained. RNA-Seq was performed using Illumina HiSeq 2500/NovaSeq 6000 and whole exome sequencing (WES) utilizing NextSeq500. HLA ligands were isolated from tumor tissue using immunoaffinity purification, UHPLC, and analyzed by tandem MS. Antibodies were measured in serum (NAb=27) utilizing the KREX™ CT262 protein array. Data analysis focused on 312 proteins (KREX™ CT262 panel + overexpressed self-proteins).Results183 and 94 of HLA class I and II TAP were identified by comparative profiling with healthy tonsils. Genes from 26 TAP were overexpressed in tumors compared to healthy mucosa (LFC>1; FDR

Abstract Biological activity of boron-containing compounds (BCCs) has been well-known. Growing interest and numerous applications for BCCs have been reported. Boron and boron-containing acids show low acute toxicity in mammals but data on halogenated boroxine (HB) - dipotassium-trioxohydroxytetrafluorotriborate, K2(B3O3F4OH) acute toxicity have not been reported before. This compound, characterized as a potential therapeutic for skin changes, exhibits no observable genotoxicity in doses lower that 0.1 mg/ml in vitro and 55 mg/kg in vivo. It has also been confirmed as an antitumour agent both in vitro and in vivo as well as an inhibitor of enzymes involved in antioxidant mechanisms. The aim of this study was to assess the acute toxicity of HB and to determine the maximum tolerated dose as well as a dose free of any signs of toxicity in different test organisms. Acute toxicity of HB was tested in Sprague-Dawley and Wistar rats and BALB/c mice after single parenteral application of different doses. We determined doses free of any sign of toxicity and LD50 after single dose administration. LD50 of HB ranges from 63 to 75 mg/kg in different test models, meaning that HB shows moderate toxicity.

Aim: Recently, a tumor cell-platelet interaction was identified in different tumor entities, resulting in a transfer of tumor-derived RNA into platelets, named further “tumor-educated platelets (TEP)”. The present pilot study aims to investigate whether such a tumor-platelet transfer of RNA occurs also in patients suffering from head and neck squamous cell carcinoma (HNSCC). Methods: Sequencing analysis of RNA derived from platelets of tumor patients (TPs) and healthy donors (HDs) were performed. Subsequently, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used for verification of differentially expressed genes in platelets from TPs and HDs in a second cohort of patients and HDs. Data were analyzed by applying bioinformatic tools. Results: Sequencing of RNA derived from the tumor as well as from platelets of TPs and HDs revealed 426 significantly differentially existing RNA, at which 406 RNA were more and 20 RNA less abundant in platelets from TPs in comparison to that of HDs. In TPs’ platelets, abundantly existing RNA coding for 49 genes were detected, characteristically expressed in epithelial cells and RNA, the products of which are involved in tumor progression. Applying bioinformatic tools and verification on a second TP/HD cohort, collagen type I alpha 1 chain (COL1A1) and zinc finger protein 750 (ZNF750) were identified as the strongest potentially platelet-RNA-sequencing (RNA-seq)-based biomarkers for HNSCC. Conclusions: These results indicate a transfer of tumor-derived messenger RNA (mRNA) into platelets of HNSCC patients. Therefore, analyses of a patient’s platelet RNA could be an efficient option for liquid biopsy in order to diagnose HNSCC or to monitor tumorigenesis as well as therapeutic responses at any time and in real time.