A phase 3, randomised, observer-blinded, placebo controlled-trial evaluating the safety and immunogenicity of investigational SARS-CoV-2 mRNA vaccine CVnCoV in adult healthcare workers in Mainz (Germany).

Background: CV-NCOV-005 was conducted to generate additional safety and immunogenicity data for the former CVnCoV SARS-CoV-2 mRNA vaccine candidate in healthcare workers (HCW). Methods: Randomised, observer blinded, placebo-controlled, phase 3 trial performed at the University Medical Center Mainz, Germany. HCWs aged ≥18 years with no history of SARS-CoV-2 infection/positive serology were randomly assigned to receive two doses of CVnCoV, or two doses of placebo (0.9% NaCl). The primary objectives were to expand the safety database of CVnCoV and assess antibody responses against SARS-CoV-2. Primary safety and reactogenicity outcomes included solicited adverse events (AEs) within 7 days after each dose and unsolicited AEs within 28 days after each dose, with safety follow-up for 13 months after first vaccination. Since HCWs became eligible to receive an authorised vaccine during enrolment and efficacy results from HERALD CVnCoV trial were made available on 30th of June 2021, this study was unblinded and converted to an open label design. Results: Most participants in the CVnCoV group reported at least one solicited AE, a relatively high number being Grade 3 (43.3% in CVnCoV group and 6.4% in placebo group). Most AEs were short in duration and did not affect vaccine compliance. The percentage of participants with unsolicited AEs up to 28 days after any dose was slightly higher in CVnCoV group (37.0%) compared with placebo group (31.2%). IgG binding antibodies against the receptor binding domain of the SARS-CoV-2 spike protein were observed after vaccination, with higher seroconversion rates and antibody levels after the second dose. Conclusion: No safety concerns for CVnCoV were identified up to 1 year post second dose. IgG responses against SARS-CoV-2 were observed after two doses, with a higher seroconversion rate and antibody levels observed after second vaccination.Study registration: ClinicalTrials.gov NCT04674189, study period: 23rd of December 2020 to 8th of June 2022.

Degradation of CCNK/CDK12 is a druggable vulnerability of colorectal cancer.

Novel treatment options for metastatic colorectal cancer (CRC) are urgently needed to improve patient outcome. Here, we screen a library of non-characterized small molecules against a heterogeneous collection of patient-derived CRC spheroids. By prioritizing compounds with inhibitory activity in a subset of-but not all-spheroid cultures, NCT02 is identified as a candidate with minimal risk of non-specific toxicity. Mechanistically, we show that NCT02 acts as molecular glue that induces ubiquitination of cyclin K (CCNK) and proteasomal degradation of CCNK and its complex partner CDK12. Knockout of CCNK or CDK12 decreases proliferation of CRC cells in vitro and tumor growth in vivo. Interestingly, sensitivity to pharmacological CCNK/CDK12 degradation is associated with TP53 deficiency and consensus molecular subtype 4 in vitro and in patient-derived xenografts. We thus demonstrate the efficacy of targeted CCNK/CDK12 degradation for a CRC subset, highlighting the potential of drug-induced proteolysis for difficult-to-treat types of cancer.

NRG1 Fusions in KRAS Wild-Type Pancreatic Cancer.

We used whole-genome and transcriptome sequencing to identify clinically actionable genomic alterations in young adults with pancreatic ductal adenocarcinoma (PDAC). Molecular characterization of 17 patients with PDAC enrolled in a precision oncology program revealed gene fusions amenable to pharmacologic inhibition by small-molecule tyrosine kinase inhibitors in all patients with KRAS wild-type (KRASWT) tumors (4 of 17). These alterations included recurrent NRG1 rearrangements predicted to drive PDAC development through aberrant ERBB receptor-mediated signaling, and pharmacologic ERBB inhibition resulted in clinical improvement and remission of liver metastases in 2 patients with NRG1-rearranged tumors that had proved resistant to standard treatment. Our findings demonstrate that systematic screening of KRASWT tumors for oncogenic fusion genes will substantially improve the therapeutic prospects for a sizeable fraction of patients with PDAC.Significance: Advanced PDAC is a malignancy with few treatment options that lacks molecular mechanism-based therapies. Our study uncovers recurrent gene rearrangements such as NRG1 fusions as disease-driving events in KRASwt tumors, thereby providing novel insights into oncogenic signaling and new therapeutic options in this entity. Cancer Discov; 8(9); 1087-95. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 1047.

Selenite and methylseleninic acid epigenetically affects distinct gene sets in myeloid leukemia: A genome wide epigenetic analysis.

Selenium compounds have emerged as promising chemotherapeutic agents with proposed epigenetic effects, however the mechanisms and downstream effects are yet to be studied. Here we assessed the effects of the inorganic selenium compound selenite and the organic form methylseleninic acid (MSA) in a leukemic cell line K562, on active (histone H3 lysine 9 acetylation, H3K9ac and histone H3 lysine 4 tri-methylation, H3K4me3) and repressive (histone H3 lysine 9 tri-methylation, H3K9me3) histone marks by Chromatin immunoprecipitation followed by DNA sequencing (ChIP-Seq). Both selenite and MSA had major effects on histone marks but the effects of MSA were more pronounced. Gene ontology analysis revealed that selenite affected genes involved in response to oxygen and hypoxia, whereas MSA affected distinct gene sets associated with cell adhesion and glucocorticoid receptors, also apparent by global gene expression analysis using RNA sequencing. The correlation to adhesion was functionally confirmed by a significantly weakened ability of MSA treated cells to attach to fibronectin and linked to decreased expression of integrin beta 1. A striking loss of cellular adhesion was also confirmed in primary patient AML cells. Recent strategies to enhance the cytotoxicity of chemotherapeutic drugs by disrupting the interaction between leukemic and stromal cells in the bone marrow are of increasing interest; and organic selenium compounds like MSA might be promising candidates. In conclusion, these results provide new insight on the mechanism of action of selenium compounds, and will be of value for the understanding, usage, and development of new selenium compounds as anticancer agents.

A ribonucleotide reductase inhibitor with deoxyribonucleoside-reversible cytotoxicity.

Ribonucleotide Reductase (RNR) is the sole enzyme that catalyzes the reduction of ribonucleotides into deoxyribonucleotides. Even though RNR is a recognized target for antiproliferative molecules, and the main target of the approved drug hydroxyurea, few new leads targeted to this enzyme have been developed. We have evaluated a recently identified set of RNR inhibitors with respect to inhibition of the human enzyme and cellular toxicity. One compound, NSC73735, is particularly interesting; it is specific for leukemia cells and is the first identified compound that hinders oligomerization of the mammalian large RNR subunit. Similar to hydroxyurea, it caused a disruption of the cell cycle distribution of cultured HL-60 cells. In contrast to hydroxyurea, the disruption was reversible, indicating higher specificity. NSC73735 thus defines a potential lead candidate for RNR-targeted anticancer drugs, as well as a chemical probe with better selectivity for RNR inhibition than hydroxyurea.

Control of glioma cell migration and invasiveness by GDF-15.

Growth and differentiation factor (GDF)-15 is a member of the transforming growth factor (TGF)-ß family of proteins. GDF-15 levels are increased in the blood and cerebrospinal fluid of glioblastoma patients. Using a TCGA database interrogation, we demonstrate that high GDF-15 expression levels are associated with poor survival of glioblastoma patients. To elucidate the role of GDF-15 in glioblastoma in detail, we confirmed that glioma cells express GDF-15 mRNA and protein in vitro. To allow for a detailed functional characterization, GDF-15 expression was silenced using RNA interference in LNT-229 and LN-308 glioma cells. Depletion of GDF-15 had no effect on cell viability. In contrast, GDF-15-deficient cells displayed reduced migration and invasion, in the absence of changes in Smad2 or Smad1/5/8 phosphorylation. Conversely, exogenous GDF-15 stimulated migration and invasiveness. Large-scale expression profiling revealed that GDF-15 gene silencing resulted in minor changes in the miRNA profile whereas several genes, including members of the plasminogen activator/inhibitor complex, were deregulated at the mRNA level. One of the newly identified genes induced by GDF-15 gene silencing was the serpin peptidase inhibitor, clade E nexin group 1 (serpine1) which is induced by TGF-ß and known to inhibit migration and invasiveness. However, serpine1 down-regulation alone did not mediate GDF-15-induced promotion of migration and invasiveness. Our findings highlight the complex contributions of GDF-15 to the invasive phenotype of glioma cells and suggest anti-GDF-15 approaches as a promising therapeutic strategy.

Differentially regulated miRNAs as prognostic biomarkers in the blood of primary CNS lymphoma patients.

Despite improved therapeutic regimens, primary CNS lymphoma (PCNSL) remains a therapeutic challenge. A prognostic classification of PCNSL patients may represent an important step towards optimised patient-adapted therapy. However, only higher age and low Karnofsky Performance Status (KPS) have repeatedly been reported to be associated with shorter overall survival (OS). Here we characterised microRNA (miRNA) fingerprints in the blood of PCNSL patients with short-term survival (STS) versus long-term survival (LTS) to assess their potential as novel prognostic biomarkers. Blood was collected from patients enrolled in the G-PCNSL-SG1 trial, a phase III study for patients with newly diagnosed PCNSL. miRNAs were extracted from the blood and analysed by next generation sequencing. The STS group comprised 20 patients with a median OS of 3 months and was compared to 20 LTS patients with a median OS of 55 months. The cohorts were balanced for age and KPS. Twelve annotated miRNAs were significantly deregulated between the two groups. Among them, miR-151a-5p and miR-151b exhibited the most prominent differences. Importantly, the combination of several miRNA allowed for a good separation between short- and long-term survivors with maximal Area Under Curve (AUC) above 0.75. Besides the known miRNAs we identified putative novel miRNA candidates with potential regulatory influence of PCNSL. Finally, the differential regulation of the most promising candidate miRNAs was confirmed by real-time polymerase chain reaction (PCR) in a validation cohort consisting of 20 STS and LTS patients. In conclusion, peripheral blood miRNA expression patterns hold promise as a prognostic tool in PCNSL patients.

MicroRNA-mediated down-regulation of NKG2D ligands contributes to glioma immune escape.

Malignant gliomas are intrinsic brain tumors with a dismal prognosis. They are well-adapted to hypoxic conditions and poorly immunogenic. NKG2D is one of the major activating receptors of natural killer (NK) cells and binds to several ligands (NKG2DL). Here we evaluated the impact of miRNA on the expression of NKG2DL in glioma cells including stem-like glioma cells. Three of the candidate miRNA predicted to target NKG2DL were expressed in various glioma cell lines as well as in glioblastomas in vivo: miR-20a, miR-93 and miR-106b. LNA inhibitor-mediated miRNA silencing up-regulated cell surface NKG2DL expression, which translated into increased susceptibility to NK cell-mediated lysis. This effect was reversed by neutralizing NKG2D antibodies, confirming that enhanced lysis upon miRNA silencing was mediated through the NKG2D system. Hypoxia, a hallmark of glioblastomas in vivo, down-regulated the expression of NKG2DL on glioma cells, associated with reduced susceptibility to NK cell-mediated lysis. This process, however, was not mediated through any of the examined miRNA. Accordingly, both hypoxia and the expression of miRNA targeting NKG2DL may contribute to the immune evasion of glioma cells at the level of the NKG2D recognition pathway. Targeting miRNA may therefore represent a novel approach to increase the immunogenicity of glioblastoma.