Therapeutic targeting of TRAIL death receptors.

The discovery of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) along with its potent and selective antitumor effects initiated a decades-long search for therapeutic strategies to target the TRAIL pathway. First-generation approaches were focused on the development of TRAIL receptor agonists (TRAs), including recombinant human TRAIL (rhTRAIL) and TRAIL receptor-targeted agonistic antibodies. While such TRAIL pathway-targeted therapies showed promise in preclinical data and clinical trials have been conducted, none have advanced to FDA approval. Subsequent second-generation approaches focused on improving upon the specific limitations of first-generation approaches by ameliorating the pharmacokinetic profiles and agonistic abilities of TRAs as well as through combinatorial approaches to circumvent resistance. In this review, we summarize the successes and shortcomings of first- and second-generation TRAIL pathway-based therapies, concluding with an overview of the discovery and clinical introduction of ONC201, a compound with a unique mechanism of action that represents a new generation of TRAIL pathway-based approaches. We discuss preclinical and clinical findings in different tumor types and provide a unique perspective on translational directions of the field.

Divergent age-related humoral correlates of protection against respiratory syncytial virus infection in older and young adults: a pilot, controlled, human infection challenge model.

BACKGROUND: Respiratory viral infections are typically more severe in older adults. Older adults are more vulnerable to infection and do not respond effectively to vaccines due to a combination of immunosenescence, so-called inflamm-ageing, and accumulation of comorbidities. Although age-related changes in immune responses have been described, the causes of this enhanced respiratory disease in older adults remain poorly understood. We therefore performed volunteer challenge with respiratory syncytial virus (RSV) in groups of younger and older adult volunteers. The aim of this study was to establish the safety and tolerability of this model and define age-related clinical, virological, and immunological outcomes. METHODS: In this human infection challenge pilot study, adults aged 18-55 years and 60-75 years were assessed for enrolment using protocol-defined inclusion and exclusion criteria. Symptoms were documented by self-completed diaries and viral load determined by quantitative PCR of nasal lavage. Peripheral blood B cell frequencies were measured by enzyme-linked immunospot and antibodies against pre-fusion and post-fusion, NP, and G proteins in the blood and upper respiratory tract were measured. The study was registered with ClinicalTrials.gov, NCT03728413. FINDINGS: 381 adults aged 60-75 years (older cohort) and 19 adults aged 18-55 years (young cohort) were assessed for enrolment using protocol-defined inclusion and exclusion criteria between Nov 12, 2018, and Feb 26, 2020. 12 healthy volunteers aged 60-75 years and 21 aged 18-55 years were inoculated intranasally with RSV Memphis-37. Nine (67%) of the 12 older volunteers became infected, developing mild-to-moderate upper respiratory tract symptoms that resolved without serious adverse events or sequelae. Viral load peaked on day 6 post-inoculation and symptoms peaked between days 6 and 8. Increases in circulating IgG-positive and IgA-positive antigen-specific plasmablasts, serum neutralising antibodies, and pre-F specific IgG were similar younger and older adults. However, in contrast to young participants, secretory IgA titres in older volunteers failed to increase during infection and, unlike serum IgG, did not correlate with protection. INTERPRETATION: Better understanding of age-related differences in clinical outcomes and immune correlates of protection can overcome reduction in vaccine efficacy with advancing age. We identify correlates of protection in older adults, revealing previously unrecognised factors which might have implications for targeted vaccine discovery and drug development in this vulnerable group. FUNDING: Medical Research Council and GlaxoSmithKline EMINENT Consortium.

Preclinical studies with ONC201/TIC10 and lurbinectedin as a novel combination therapy in small cell lung cancer (SCLC).

The American Cancer Society estimates that ~15% of all lung cancers are categorized as small cell lung cancer (SCLC) with an overall five-year survival rate of less than 7%. Due to disease aggressiveness, more other malignancies, the standard of care is based on clinical efficacy rather than helpful biomarkers. Lurbinectedin is a small molecule RNA polymerase II inhibitor that binds the minor groove of DNA to induce double-strand breaks. Lurbinectedin has efficacy towards SCLC cells at sub-nM concentration and received accelerated FDA approval in 2020 for metastatic SCLC that progressed on platinum-based therapy. ONC201/TIC10 is a TRAIL pathway-inducing compound that with demonstrated clinical efficacy in H3K27M-mutated diffuse midline glioma and neuroendocrine tumors, in early phase clinical trials. We hypothesized that combining ONC201 and lurbinectedin may yield synergistic and targeted killing of SCLC cells. SCLC cell lines H1048, H1105, H1882, and H1417 were treated with ONC201 and lurbinectedin and cell viability was determined using a CellTiter-Glo assay using varying drug concentrations. Synergistic growth inhibition of SCLC cells was noted with combination of ONC201 and lurbinectedin. Induction of the integrated stress response mediator ATF4 and CHOP was observed with ONC201 and lurbinectedin along with induction of PARP cleavage indicative of apoptosis in response to cellular stress. Additionally, SCLC lines treated with the combination therapy displayed increased DNA breakage-related proteins such as phosphorylated Chk-1, Wee1 and γ-H2AX. Combination index revealed the most potent synergy occurred at the concentrations of 0.16 µM ONC201 and 0.05 nM lurbinectedin in the H1048 cell line, demonstrating highly efficient and selective killing of these tumor cells in vitro. While these therapies showed potency against the cell lines derived from SCLC patients, it is noteworthy that the combination showed significantly less toxicity to healthy human lung epithelial cells. Future studies could explore the combination of ONC201 and lurbinectedin in SCLC cell lines, SCLC patient-derived organoids, other tumor types, including in vivo studies and clinical translation.

Lamb1a regulates atrial growth by limiting second heart field addition during zebrafish heart development.

During early vertebrate heart development, the heart transitions from a linear tube to a complex asymmetric structure, a morphogenetic process that occurs simultaneously with growth of the heart. Cardiac growth during early heart morphogenesis is driven by deployment of cells from the second heart field (SHF) into both poles of the heart. Laminin is a core component of the extracellular matrix and, although mutations in laminin subunits are linked with cardiac abnormalities, no role for laminin has been identified in early vertebrate heart morphogenesis. We identified tissue-specific expression of laminin genes in the developing zebrafish heart, supporting a role for laminins in heart morphogenesis. Analysis of heart development in lamb1a zebrafish mutant embryos reveals mild morphogenetic defects and progressive cardiomegaly, and that Lamb1a functions to limit heart size during cardiac development by restricting SHF addition. lamb1a mutants exhibit hallmarks of altered haemodynamics, and blocking cardiac contractility in lamb1a mutants rescues heart size and atrial SHF addition. Together, these results suggest that laminin mediates interactions between SHF deployment and cardiac biomechanics during heart morphogenesis and growth in the developing embryo.

Inflammatory profiles across the spectrum of disease reveal a distinct role for GM-CSF in severe COVID-19.

While it is now widely accepted that host inflammatory responses contribute to lung injury, the pathways that drive severity and distinguish coronavirus disease 2019 (COVID-19) from other viral lung diseases remain poorly characterized. We analyzed plasma samples from 471 hospitalized patients recruited through the prospective multicenter ISARIC4C study and 39 outpatients with mild disease, enabling extensive characterization of responses across a full spectrum of COVID-19 severity. Progressive elevation of levels of numerous inflammatory cytokines and chemokines (including IL-6, CXCL10, and GM-CSF) were associated with severity and accompanied by elevated markers of endothelial injury and thrombosis. Principal component and network analyses demonstrated central roles for IL-6 and GM-CSF in COVID-19 pathogenesis. Comparing these profiles to archived samples from patients with fatal influenza, IL-6 was equally elevated in both conditions whereas GM-CSF was prominent only in COVID-19. These findings further identify the key inflammatory, thrombotic, and vascular factors that characterize and distinguish severe and fatal COVID-19.