Automated antigen assays display a high heterogeneity for the detection of SARS-CoV-2 variants of concern, including several Omicron sublineages.

Diagnostic tests for direct pathogen detection have been instrumental to contain the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic. Automated, quantitative, laboratory-based nucleocapsid antigen (Ag) tests for SARS-CoV-2 have been launched alongside nucleic acid-based test systems and point-of-care (POC) lateral-flow Ag tests. Here, we evaluated four commercial Ag tests on automated platforms for the detection of different sublineages of the SARS-CoV-2 Omicron variant of concern (VoC) (B.1.1.529) in comparison with "non-Omicron" VoCs. A total of 203 Omicron PCR-positive respiratory swabs (53 BA.1, 48 BA.2, 23 BQ.1, 39 XBB.1.5 and 40 other subvariants) from the period February to March 2022 and from March 2023 were examined. In addition, tissue culture-expanded clinical isolates of Delta (B.1.617.2), Omicron-BA.1, -BF.7, -BN.1 and -BQ.1 were studied. These results were compared to previously reported data from 107 clinical "non-Omicron" samples from the end of the second pandemic wave (February to March 2021) as well as cell culture-derived samples of wildtype (wt) EU-1 (B.1.177), Alpha VoC (B.1.1.7) and Beta VoC (B.1.351)). All four commercial Ag tests were able to detect at least 90.9% of Omicron-containing samples with high viral loads (Ct < 25). The rates of true-positive test results for BA.1/BA.2-positive samples with intermediate viral loads (Ct 25-30) ranged between 6.7% and 100.0%, while they dropped to 0 to 15.4% for samples with low Ct values (> 30). This heterogeneity was reflected also by the tests' 50%-limit of detection (LoD50) values ranging from 44,444 to 1,866,900 Geq/ml. Respiratory samples containing Omicron-BQ.1/XBB.1.5 or other Omicron subvariants that emerged in 2023 were detected with enormous heterogeneity (0 to 100%) for the intermediate and low viral load ranges with LoD50 values between 23,019 and 1,152,048 Geq/ml. In contrast, detection of "non-Omicron" samples was more sensitive, scoring positive in 35 to 100% for the intermediate and 1.3 to 32.9% of cases for the low viral loads, respectively, corresponding to LoD50 values ranging from 6181 to 749,792 Geq/ml. All four assays detected cell culture-expanded VoCs Alpha, Beta, Delta and Omicron subvariants carrying up to six amino acid mutations in the nucleocapsid protein with sensitivities comparable to the non-VoC EU-1. Overall, automated quantitative SARS-CoV-2 Ag assays are not more sensitive than standard rapid antigen tests used in POC settings and show a high heterogeneity in performance for VoC recognition. The best of these automated Ag tests may have the potential to complement nucleic acid-based assays for SARS-CoV-2 diagnostics in settings not primarily focused on the protection of vulnerable groups. In light of the constant emergence of new Omicron subvariants and recombinants, most recently the XBB lineage, these tests' performance must be regularly re-evaluated, especially when new VoCs carry mutations in the nucleocapsid protein or immunological and clinical parameters change.

Rapid and sensitive identification of omicron by variant-specific PCR and nanopore sequencing: paradigm for diagnostics of emerging SARS-CoV-2 variants.

On November 26, 2021, the World Health Organization classified B.1.1.529 as a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern (VoC), named omicron. Spike-gene dropouts in conventional SARS-CoV-2 PCR systems have been reported over the last weeks as indirect diagnostic evidence for the identification of omicron. Here, we report the combination of PCRs specific for heavily mutated sites in the spike gene and nanopore-based full-length genome sequencing for the rapid and sensitive identification of the first four COVID-19 patients diagnosed in Germany to be infected with omicron on November 28, 2021. This study will assist the unambiguous laboratory-based diagnosis and global surveillance for this highly contagious VoC with an unprecedented degree of humoral immune escape. Moreover, we propose that specialized diagnostic laboratories should continuously update their assays for variant-specific PCRs in the spike gene of SARS-CoV-2 to readily detect and diagnose emerging variants of interest and VoCs. The combination with established nanopore sequencing procedures allows both the rapid confirmation by whole genome sequencing as well as the sensitive identification of newly emerging variants of this pandemic ß-coronavirus in years to come.

Genomic epidemiology reveals multiple introductions of SARS-CoV-2 followed by community and nosocomial spread, Germany, February to May 2020.

BackgroundIn the SARS-CoV-2 pandemic, viral genomes are available at unprecedented speed, but spatio-temporal bias in genome sequence sampling precludes phylogeographical inference without additional contextual data.AimWe applied genomic epidemiology to trace SARS-CoV-2 spread on an international, national and local level, to illustrate how transmission chains can be resolved to the level of a single event and single person using integrated sequence data and spatio-temporal metadata.MethodsWe investigated 289 COVID-19 cases at a university hospital in Munich, Germany, between 29 February and 27 May 2020. Using the ARTIC protocol, we obtained near full-length viral genomes from 174 SARS-CoV-2-positive respiratory samples. Phylogenetic analyses using the Auspice software were employed in combination with anamnestic reporting of travel history, interpersonal interactions and perceived high-risk exposures among patients and healthcare workers to characterise cluster outbreaks and establish likely scenarios and timelines of transmission.ResultsWe identified multiple independent introductions in the Munich Metropolitan Region during the first weeks of the first pandemic wave, mainly by travellers returning from popular skiing areas in the Alps. In these early weeks, the rate of presumable hospital-acquired infections among patients and in particular healthcare workers was high (9.6% and 54%, respectively) and we illustrated how transmission chains can be dissected at high resolution combining virus sequences and spatio-temporal networks of human interactions.ConclusionsEarly spread of SARS-CoV-2 in Europe was catalysed by superspreading events and regional hotspots during the winter holiday season. Genomic epidemiology can be employed to trace viral spread and inform effective containment strategies.

Fenretinide Acts as Potent Radiosensitizer for Treatment of Rhabdomyosarcoma Cells.

Fusion-positive rhabdomyosarcoma (FP-RMS) is a highly aggressive childhood malignancy which is mainly treated by conventional chemotherapy, surgery and radiation therapy. Since radiotherapy is associated with a high burden of late side effects in pediatric patients, addition of radiosensitizers would be beneficial. Here, we thought to assess the role of fenretinide, a potential agent for FP-RMS treatment, as radiosensitizer. Survival of human FP-RMS cells was assessed after combination therapy with fenretinide and ionizing radiation (IR) by cell viability and clonogenicity assays. Indeed, this was found to significantly reduce cell viability compared to single treatments. Mechanistically, this was accompanied by enhanced production of reactive oxygen species, initiation of cell cycle arrest and induction of apoptosis. Interestingly, the combination treatment also triggered a new form of dynamin-dependent macropinocytosis, which was previously described in fenretinide-only treated cells. Our data suggest that fenretinide acts in combination with IR to induce cell death in FP-RMS cells and therefore might represent a novel radiosensitizer for the treatment of this disease.

The ADAM17-directed Inhibitory Antibody MEDI3622 Antagonizes Radiotherapy-induced VEGF Release and Sensitizes Non-Small Cell Lung Cancer for Radiotherapy.

The cellular response to ionizing radiation (IR) depends on tumor cell and microenvironmental factors. Here, we investigated the role of IR-induced ADAM17 matrix metalloproteinase activity for the intercellular communication between tumor cells and the tumor vasculature in non-small cell lung cancer (NSCLC) tumor models. Factors shed by ADAM17 from NSCLC tumor cells (A549, H358) and relevant for endothelial cell migration were investigated using transwell migration assays, ELISA, and flow cytometry. Tumor angiogenesis-related endpoints were analyzed with the chorio-allantoic membrane assay and in murine NSCLC tumor models. Efficacy-oriented experiments were performed in a murine orthotopic NSCLC tumor model using irradiation with an image-guided small-animal radiotherapy platform alone and in combination with the novel ADAM17-directed antibody MEDI3622. In vitro, VEGF was identified as the major factor responsible for IR-induced and ADAM17-dependent endothelial cell migration toward attracting tumor cells. IR strongly enhanced tumor cell-associated ADAM17 activity, released VEGF in an ADAM17-dependent manner, and thereby coordinated the communication between tumor and endothelial cells. In vivo, tumor growth and microvessel size and density were strongly decreased in response to the combined treatment modality of IR and MEDI3622 but not by either treatment modality alone and thus suggest that the supra-additive effect of the combined treatment modality is in part due to abrogation of the ADAM17-mediated IR-induced protective effect on the tumor vasculature. Furthermore, we demonstrate that the novel ADAM17-inhibitory antibody MEDI3622 potently improves the radiotherapy response of NSCLC. Significance: The tumor response to radiotherapy is influenced by several factors of the tumor microenvironment. We demonstrate that inhibition of the sheddase ADAM17 by the novel antibody MEDI3622 reduces IR-induced VEGF release from tumor cells relevant for endothelial cell migration and vasculature protection, thereby enhancing radiotherapy treatment outcome of NSCLC.

Consolidation cetuximab after concurrent triplet radiochemotherapy+cetuximab in patients with advanced head and neck cancer: A randomized phase II study.

BACKGROUND AND PURPOSE: Preclinical data suggest that cetuximab should be continued after end of concurrent radiotherapy+cetuximab due to its efficacy against residual tumor cells in the irradiated tumor bed. Based on this concept the phase II add-on cetuximab (AOC) study was designed. MATERIALS AND METHODS: Altogether 63 patients with advanced head and neck cancer were treated with radiochemotherapy (70 Gy, cisplatin 40 mg/m2 weekly) in combination with concurrent cetuximab (loading dose 400 mg/m2, then 250 mg/m2 weekly). Thereafter patients were randomized to cetuximab consolidation (500 mg/m2 biweekly × 6) or no further treatment. The primary endpoint was the 2-year locoregional control (LRC) rate. As translational research endpoints serum markers were analyzed before and during treatment and CT-based quantitative image analysis (radiomics) was performed. RESULTS: Median follow-up was 24 months. The 2-year LRC rates were 67.9% and 67.7% in the treatment arms with and without consolidation cetuximab, respectively. Higher than median levels of three serum markers were negatively associated with the 2-year LRC rate in the overall patient cohort: Osteopontin, IL8 and FasL2 (p ≤ 0.05). A radiomics model consisting of two radiomics features could be built showing that higher entropy and higher complexity of tumor Hounsfield unit distribution indicates worse LRC (concordance index 0.66). No correlation was found between biological and imaging markers. CONCLUSIONS: There was no evidence that consolidation cetuximab would improve the 2-year LRC rate. Prognostic biological and imaging markers could be identified for the overall patient cohort. Studies with larger patient numbers are needed to correlate biological and imaging markers.

The hypoxia-activated prodrug evofosfamide in combination with multiple regimens of radiotherapy.

The promising treatment combination of ionizing radiation (IR) with a hypoxia-activated prodrug (HAP) is based on biological cooperation. Here we investigated the hypoxia-activated prodrug evofosfamide in combination with different treatment regimens of IR against lung A549- and head&neck UT-SCC-14-derived tumor xenografts. DNA damage-related endpoints and clonogenic cell survival of A549 and UT-SCC-14 carcinoma cells were probed under normoxia and hypoxia.Evofosfamide (TH-302) induced DNA-damage and a dose-dependent antiproliferative response in A549 cells on cellular pretreatment under hypoxia, and supra-additively reduced clonogenic survival in combination with IR. Concomitant treatment of A549-derived tumor xenografts with evofosfamide and fractionated irradiation induced the strongest treatment response in comparison to the corresponding neoadjuvant and adjuvant regimens. Adjuvant evofosfamide was more potent than concomitant and neoadjuvant evofosfamide when combined with a single high dose of IR. Hypoxic UT-SCC-14 cells and tumor xenografts thereof were resistant to evofosfamide alone and in combination with IR, most probably due to reduced P450 oxidoreductase expression, which might act as major predictive determinant of sensitivity to HAPs.In conclusion, evofosfamide with IR is a potent combined treatment modality against hypoxic tumors. However, the efficacy and the therapeutic outcome of this combined treatment modality is, as indicated here in preclinical tumor models, dependent on scheduling parameters and tumor type, which is most probably related to the status of respective HAP-activating oxidoreductases. Further biomarker development is necessary for the launch of successful clinical trials.

Secretome Signature Identifies ADAM17 as Novel Target for Radiosensitization of Non-Small Cell Lung Cancer.

PURPOSE: Ionizing radiation (IR) induces intracellular signaling processes as part of a treatment-induced stress response. Here we investigate IR-induced ADAM17 activation and the role of ADAM17-shed factors for radiation resistance in non-small cell lung cancer. EXPERIMENTAL DESIGN: Large-scale secretome profiling was performed using antibody arrays. Secretion kinetics of ADAM17 substrates was determined using ELISA across multiple in vitro and in vivo models of non-small cell lung cancer. Clonogenic survival and tumor xenograft assays were performed to determine radiosensitization by ADAM17 inhibition. RESULTS: On the basis of a large-scale secretome screening, we investigated secretion of auto- or paracrine factors in non-small cell lung cancer in response to irradiation and discovered the ADAM17 network as a crucial mediator of resistance to IR. Irradiation induced a dose-dependent increase of furin-mediated cleavage of the ADAM17 proform to active ADAM17, which resulted in enhanced ADAM17 activity in vitro and in vivo Genetic or pharmacologic targeting of ADAM17 suppressed IR-induced shedding of secreted factors, downregulated ErbB signaling in otherwise cetuximab-resistant target cells, and enhanced IR-induced cytotoxicity. The combined treatment modality of IR with the ADAM17 inhibitor TMI-005 resulted in a supra-additive antitumor response in vivo demonstrating the potential of ADAM17 targeting in combination with radiotherapy. CONCLUSIONS: Radiotherapy activates ADAM17 in non-small cell lung cancer, which results in shedding of multiple survival factors, growth factor pathway activation, and IR-induced treatment resistance. We provide a sound rationale for repositioning ADAM17 inhibitors as short-term adjuvants to improve the radiotherapy outcome of non-small cell lung cancer. Clin Cancer Res; 22(17); 4428-39. ©2016 AACR.

Combined treatment strategies for microtubule stabilizing agent-resistant tumors.

BACKGROUND: Resistance to microtubule-stabilizing agents is a major hurdle for successful cancer therapy. We investigated combined treatment of microtubule-stabilizing agents (MSAs) with inhibitors of angiogenesis to overcome MSA resistance. METHODS: Treatment regimens of clinically relevant MSAs (patupilone and paclitaxel) and antiangiogenic agents (everolimus and bevacizumab) were investigated in genetically defined MSA-resistant lung (A549EpoB40) and colon adenocarcinoma (SW480) tumor xenografts in nude mice (CD1-Foxn1, ICRnu; 5-14 per group). Tumor growth delays were calculated by Kaplan-Meier analysis with Holm-Sidak tests. All statistical tests were two-sided. RESULTS: Inhibition of mTOR-kinase by everolimus only minimally reduced the proliferative activity of ß tubulin-mutated lung adenocarcinoma cells alone and in combination with the MSA patupilone, but everolimus inhibited expression and secretion of vascular endothelial growth factor (VEGF) from these cells. mTOR-kinase inhibition strongly sensitized tumor xenografts derived from these otherwise MSA-resistant tumor cells to patupilone. Tumors treated with the combined modality of everolimus and patupilone had statistically significantly reduced tumor volume and stronger tumor growth delay (16.2 ± 1.01 days) than control- (7.7 ± 0.3 days, P = .004), patupilone- (10 ± 0.97 days, P = .009), and everolimus-treated (10.6 ± 1.4 days, P = .014) tumors. A combined treatment modality with bevacizumab also resensitized this MSA-refractory tumor model to patupilone. Treatment combination also strongly reduced microvessel density, corroborating the relevance of VEGF targeting for the known antivasculature-directed potency of MSA alone in MSA-sensitive tumor models. Resensitization to MSAs was also probed in P glycoprotein-overexpressing SW480-derived tumor xenografts. Different bevacizumab regimens also sensitized this otherwise-resistant tumor model to clinically relevant MSA paclitaxel. CONCLUSIONS: A treatment combination of MSAs with antiangiogenic agents is potent to overcome tumor cell-linked MSA resistance and should be considered as strategy for MSA-refractory tumor entities.

An MRAS, SHOC2, and SCRIB complex coordinates ERK pathway activation with polarity and tumorigenic growth.

SHOC2 is mutated in Noonan syndrome and plays a key role in the activation of the ERK-MAPK pathway, which is upregulated in the majority of human cancers. SHOC2 functions as a PP1-regulatory protein and as an effector of MRAS. Here we show that SHOC2 and MRAS form a complex with SCRIB, a polarity protein with tumor suppressor properties. SCRIB functions as a PP1-regulatory protein and antagonizes SHOC2-mediated RAF dephosphorylation through a mechanism involving competition for PP1 molecules within the same macromolecular complex. SHOC2 function is selectively required for the malignant properties of tumor cells with mutant RAS, and both MRAS and SHOC2 play a key role in polarized migration. We propose that MRAS, through its ability to recruit a complex with paradoxical components, coordinates ERK pathway spatiotemporal dynamics with polarity and that this complex plays a key role during tumorigenic growth.

[Methodical influence on selected parameters of the acid-base equilibrium in urine samples from dairy cows]. / Methodische Einflüsse auf ausgewählte Parameter des Säure-Basen-Haushaltes in Harnproben von Milchkühen.

Estimation of net acid base excretion (NABE) in urine samples of dairy cows has often been reported in the veterinary literature. NABE has been proved to be meaningful in estimation of disturbances in the cows acid base equilibrium. In order to examine the meaningfulness of this method different factors with possible influences on NABE were tested. Estimation of simple and fractionated NABE lead to comparable results. Whereas implementation of fractionated NABE is linked with higher expense, simple NABE gives information at lower expense. After four days storing of urine samples in the refrigerator the concentration of NH4+ increased significantly. In view of using this parameter to estimate the acid metabolic situation this may lead to false information. Therefore urine samples should be examined at least within three days after collecting and refrigerated storing. Sediment distribution significantly influenced all urine parameters. Above all the shift of the values into direction of the reference limit may result in the assessment of individual cows as risk group. Homogeneous mixing of the urine samples must be carried out before NSBA-determination. A higher air portion in the sample containers lead to a significant increase of the pH in urine samples. To prevent influences of the air on urine samples, sample containers should be filled completely.