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46 result(s) for "Ochsenreither, Sebastian"
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Proteogenomic analysis reveals RNA as a source for tumor-agnostic neoantigen identification
Systemic pan-tumor analyses may reveal the significance of common features implicated in cancer immunogenicity and patient survival. Here, we provide a comprehensive multi-omics data set for 32 patients across 25 tumor types for proteogenomic-based discovery of neoantigens. By using an optimized computational approach, we discover a large number of tumor-specific and tumor-associated antigens. To create a pipeline for the identification of neoantigens in our cohort, we combine DNA and RNA sequencing with MS-based immunopeptidomics of tumor specimens, followed by the assessment of their immunogenicity and an in-depth validation process. We detect a broad variety of non-canonical HLA-binding peptides in the majority of patients demonstrating partially immunogenicity. Our validation process allows for the selection of 32 potential neoantigen candidates. The majority of neoantigen candidates originates from variants identified in the RNA data set, illustrating the relevance of RNA as a still understudied source of cancer antigens. This study underlines the importance of RNA-centered variant detection for the identification of shared biomarkers and potentially relevant neoantigen candidates. RNA variants derived from cancer-associated RNA editing events can be a source of neoantigens. Here, based on a proteogenomic pipeline combining DNA and RNA sequencing with MS-based immunopeptidomics, the authors identity and validate potential neoantigen candidates in patients with different tumor entities, highlighting RNA as important neoantigen source.
A macrophage-predominant immunosuppressive microenvironment and therapeutic vulnerabilities in advanced salivary gland cancer
Salivary gland cancers are rare, diverse malignancies characterized by poor response to immunotherapy. The tumor immune environment in these cancers remains poorly understood. To address this, we perform an integrative analysis of the tumor immune microenvironment in a large cohort of advanced salivary gland cancer samples. Most tumors exhibit low immune activity with limited immune cell infiltration. Inflammation is linked to higher tumor mutational burden in non-adenoid cystic carcinoma histologies. Subtype specific expression of immune checkpoints is identified with prominent expression of VTCN1 in luminal-like cells within adenoid cystic carcinoma. Macrophages with immunosuppressive properties dominate the immune microenvironment across subtypes. Responses to immunotherapy are limited and associated with a higher ratio of T-cells relative to macrophages in individual cases, warranting further investigation. Here, we show an immunosuppressive environment in salivary gland cancers and identify subtype-specific immune vulnerabilities that could inform tailored therapeutic strategies. Salivary gland cancers (SGC) respond poorly to immunotherapies and new treatment strategies are needed. Here, the authors develop an integrated analysis of advanced SGC to characterize the immune microenvironment and identify potential therapeutic vulnerabilities.
Aldehyde dehydrogenase 1 isoenzyme expression as a marker of cancer stem cells correlates to histopathological features in head and neck cancer: A meta-analysis
There is a lack of predictive biomarkers that can identify patients with head and neck squamous cell carcinoma (HNSCC) who will experience treatment failure and develop drug resistance, recurrence, and metastases. Cancer stem-like cells (CSC) were identified as a subset of cells within the tumor in a variety of solid tumors including HNSCC. CSC are considered the tumor-initiating population responsible for recurrence or metastasis and are associated with therapy resistance. This meta-analysis including fourteen studies with altogether 1258 patients updates and summarizes all relevant data on the impact of ALDH1+ CSC on the prognosis of HNSCC and its association with clinicopathological parameters. ALDH1 expression is highly correlated with tumor differentiation (G3 vs. G1+G2; odds ratio = 2.85. 95% CI: 1.72-4.73, P<0.0001) and decreased overall survival (relative risk = 1.77. 95% CI: 1.41-2.22, P<0.0001) if one out of seven studies was excluded because of heterogeneity. These findings provide insights into the understanding of more aggressive tumor phenotypes and also suggest that the prognostic value provided by HNSCC-subtyping by CSC frequency warrant further clinical investigation.
Cancer testis antigen Cyclin A1 harbors several HLA-A02:01-restricted T cell epitopes, which are presented and recognized in vivo
Cyclin A1 is a promising antigen for T cell therapy being selectively expressed in high-grade ovarian cancer (OC) and acute myeloid leukemia (AML) stem cells. For adoptive T cell therapy, a single epitope has to be selected, with high affinity to MHC class I and adequate processing and presentation by malignant cells to trigger full activation of specific T cells. In silico prediction with three algorithms indicated 13 peptides of Cyclin A1 9 to 11 amino acids of length to have high affinity to HLA-A*02:01. Ten of them proved to be affine in an HLA stabilization assay using TAP-deficient T2 cells. Their immunogenicity was assessed by repetitive stimulation of CD8+ T cells from two healthy donors with single-peptide-pulsed dendritic cells or monocytes. Intracellular cytokine staining quantified the enrichment of peptide-specific functional T cells. Seven peptides were immunogenic, three of them against both donors. Specific cell lines were cloned and used in killing assays to demonstrate recognition of endogenous Cyclin A1 in the HLA-A*02:01-positive AML cell line THP-1. Immunopeptidome analysis based on direct isolation of HLA-presented peptides by mass spectrometry of primary AML and OC samples identified four naturally presented epitopes of Cyclin A1. The immunopeptidome of HeLa cells transfected with Cyclin A1 and HLA-A*02:01 revealed six Cyclin A1-derived HLA ligands. Epitope p410–420 showed high affinity to HLA-A*02:01 and immunogenicity in both donors. It proved to be naturally presented on primary AML blast and provoked spontaneous functional response of T cells from treatment naïve OC and, therefore, warrants further development for clinical application.
Expression of the Stem Cell Markers Nestin and CD133 on Circulating Melanoma Cells
Different molecular markers have been identified for melanoma-initiating cells including CD133 and nestin. Assuming that metastasis requires a dissemination of tumor-initiating cells, presence of circulating tumor-initiating cells should be associated with worse patient outcome. In this study, 20ml blood was collected from 32 consecutive patients affected by metastatic melanoma and blood was enriched for circulating melanoma cells (CMCs) by CD45 depletion of the non-melanoma cell fraction. Multiparameter cytometry was carried out to co-stain with combinations of CD133 and nestin (NES). Six tissue samples from metastatic lesions of six different patients were stained with the same antibodies by immunohistochemistry. Percentage of NES-positive CMCs correlated with tumor burden and number of metastatic sites. Cox regression analysis revealed levels of lactate dehydrogenase (LDH; hazard ratio: 12.8 (1.35–121.5); P=0.02), number of metastatic sites (hazard ratio 3.87 (1.66–9.03); P=0.02), tumor burden (hazard ratio 5.72 (1.57–20.9); P=0.01), and percentage of NES-expressing CMCs≥35% (hazard ratio 5.73 (1.66–19.7); P=0.006) to be factors related to shorter overall survival. CD133- and NES-expression profiles on CMCs were similar to matched metastatic tissue. These findings show that CMCs expressed stem cell-associated markers NES and CD133. Higher expression of NES on CMCs might represent an index of poor prognosis.
Peritoneal carcinosis in male germ cell tumor patients: a registry study compiled by the German Testicular Cancer Study Group (GTCSG)
PurposeTo report on the clinical characteristics, outcome, and frequency of peritoneal carcinosis (PC) in patients with advanced germ cell tumors (GCT), a multicenter registry analysis was carried out.MethodsA multicenter registry analysis was conducted by the German Testicular Cancer Study Group (GTCSG) with international collaborators. Data was collected and analyzed retrospectively. Patients were eligible for inclusion if PC was diagnosed either by radiologic or histopathologic finding during the course of disease. Descriptive and explorative statistical analysis was carried out with cancer-specific survival (CSS) as primary study endpoint.ResultsCollaborators from ten GCT expert centers identified 28 GCT (0.77%) patients with PC after screening approximately 3767 GCT patient files and one case was contributed from a cancer registry request. Patients were diagnosed from 1997 to 2019 at a median age of 37 years (interquartile range, 13). Two patients (7%) presented with stage I and 27 patients (93%) with synchronous metastatic disease at first diagnosis. The primary histology was seminoma in seven (27%) and non-seminoma in 21 patients (72%). PC was detected after a median of 15.3 months from primary diagnosis (range 0–177) and two consecutive treatment lines (range 0–5), respectively. The median CSS from the time of detection of PC was 10.5 months (95%Confidence Interval 0.47–1.30) associated with an overall 2-year CSS rate of 30%.ConclusionPC represents a rare tumor manifestation in GCT patients and was primarily associated with the occurrence of advanced cisplatin-refractory disease conferring to a dismal prognosis.
Treatment of refractory germ-cell tumours with single-agent cabazitaxel: a German Testicular Cancer Study Group case series
PurposeOutcomes of multiply relapsed, refractory germ-cell tumour (GCT) patients remain poor with an overall survival (OS) of a few months only. Thus, new therapeutic advances are urgently needed. Cabazitaxel has shown preclinical activity in platinum-resistant GCT models. Here, we report the first clinical case series of cabazitaxel treatment for platinum-refractory GCT.MethodsData of multiply relapsed GCT patients receiving single-agent cabazitaxel were retrospectively analysed. Endpoints included 12-week progression-free survival (PFS) rate, disease control rate, tumour marker responses, median PFS and OS, and toxicity.ResultsCabazitaxel showed limited activity in 13 heavily pre-treated GCT patients. After a median follow-up of 23 weeks (IQR 29), 69% of patients were deceased. A median of 2 cycles of cabazitaxel (range 1–7) were applied. The 12-week PFS rate was 31%. Median PFS and OS were 7 and 23 weeks, respectively. Two patients achieved objective responses (15%), three patients (23%) achieved a tumour marker decline ≥ 50%, and the disease control rate was 39%. Cabazitaxel was well tolerated. CTCAE° III–IV haemato-toxicity was most common (54%), and dose reductions were scarce (15%).ConclusionIn this case series, cabazitaxel showed limited activity in heavily pre-treated GCT patients. Two-phase II studies are underway (NCT02115165, NCT02478502) prospectively assessing cabazitaxel in multiply relapsed GCTs.
Pressure-adjusted static compression: aerobic metabolism and microvascular perfusion in the context of chemotherapy-induced neuropathy
Background Chemotherapy-induced peripheral neuropathy (CIPN) involves impaired microvascular neuronal perfusion and reduced bioenergetics. Compression and cryotherapy are potential preventive measures, yet their mechanism of acral temperature reduction remains unclear. This study aims to unravel the effects of pressure-adjusted static compression (PSC) on aerobic metabolic and endothelial responses in patients undergoing chemotherapy (CTX). Methods Cancer patients with CTX above the CIPN-threshold dose ( n  = 24, 50% male; age 64 [61–71] years) and healthy controls ( n  = 53, 45% male; age 23 (18 to 87) years) had PSC applied on upper extremities. Tissue oxygenation and metabolism were derived by measuring oxygen supply (O 2 Hb), oxygen demand (HHb), tissue oxygenation (TOI) and microvascular perfusion (THb) with quantitative time-resolved near-infrared spectroscopy (NIRS) and temperature with thermography. Effects were compared to cryoapplication and intermittent pneumatic compression (IPC). Endothelial function was quantified during vascular occlusion test (VOT). Results PSC, in contrast to undersized surgical gloves (SG), uniformly creates pressure on hands and leads to a more pronounced reduction of hand temperature. Furthermore, PSC significantly increased microvascular perfusion, O 2 -supply and reduced O 2 -demand and aerobic metabolism, thus raised local tissue oxygenation ( p  < 0.05 each). CTX lead to impaired metabolic and vascular reaction to PSC with only significant reduction of O 2 -demand ( p  < 0.05) during PSC. PSC is preferable regarding comfort ( p  < 0.05) compared to SG. Cooling of hands (cooling gloves) had different action ( p  < 0.001) to PSC with significantly reduced microvascular perfusion, O 2 -supply and O 2 -demand ( p  < 0.05 each). Comparable local significant effects ( p  < 0.05) were seen during IPC. CTX exhibited endothelial dysfunction with impaired microvascular reactivity, which limited their capacity to enhance tissue oxygenation. Conclusions Reduction of oxygen demand represents an important mechanism in interventions targeting prevention of CIPN. PSC, comparable to cryoapplication and IPC attenuates energy metabolism and enhances tissue oxygenation. PSC’s impact on the combination of vascular and energy metabolism suggests its potential to alleviate CIPN burden. These findings support PSC’s role in reducing acral CIPN through distinct mechanisms.
Disulfiram Acts as a Potent Radio-Chemo Sensitizer in Head and Neck Squamous Cell Carcinoma Cell Lines and Transplanted Xenografts
The poor prognosis of locally advanced and metastatic head and neck squamous cell carcinoma (HNSCC) is primarily mediated by the functional properties of cancer stem cells (CSCs) and resistance to chemoradiotherapy. We investigated whether the aldehyde dehydrogenase (ALDH) inhibitor disulfiram (DSF) can enhance the sensitivity of therapy. Cell viability was assessed by the 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan (MTT) and apoptosis assays, and the cell cycle and reactive oxygen species (ROS) levels were evaluated by fluorescence-activated cell sorting (FACS). The radio-sensitizing effect was measured by a colony formation assay. The synergistic effects were calculated by combination index (CI) analyses. The DSF and DSF/Cu2+ inhibited the cell proliferation (inhibitory concentration 50 (IC50) of DSF and DSF/Cu2+ were 13.96 μM and 0.24 μM). DSF and cisplatin displayed a synergistic effect (CI values were <1). DSF or DSF/Cu2+ abolished the cisplatin-induced G2/M arrest (from 52.9% to 40.7% and 41.1%), and combining irradiation (IR) with DSF or DSF/Cu2+ reduced the colony formation and attenuated the G2/M arrest (from 53.6% to 40.2% and 41.9%). The combination of cisplatin, DSF or DSF/Cu2+, and IR enhanced the radio-chemo sensitivity by inducing apoptosis (42.04% and 32.21%) and ROS activity (46.3% and 37.4%). DSF and DSF/Cu2+ enhanced the sensitivity of HNSCC to cisplatin and IR. Confirming the initial data from patient-derived tumor xenograft (PDX) supported a strong rationale to repurpose DSF as a radio-chemosensitizer and to assess its therapeutic potential in a clinical setting.