Prostate cancer is the fifth leading cause of cancer death in men, responsible for over 375,000 deaths in 2020. Novel therapeutic strategies are needed to improve outcomes. Cannabinoids, chemical components of the cannabis plant, are a possible solution. Preclinical evidence demonstrates that cannabinoids can modulate several cancer hallmarks of many tumor types. However, the therapeutic potential of cannabinoids in prostate cancer has not yet been fully explored. The aim of this study was to investigate the antiproliferative and anti-invasive properties of cannabidiol (CBD) in prostate cancer cells in vitro. CBD inhibited cell viability and proliferation, accompanied by reduced expression of key cell cycle proteins, specifically cyclin D3 and cyclin-dependent kinases CDK2, CDK4, and CDK1, and inhibition of AKT phosphorylation. The effects of CBD on cell viability were not blocked by cannabinoid receptor antagonists, a transient receptor potential vanilloid 1 (TRPV1) channel blocker, or an agonist of the G-protein-coupled receptor GPR55, suggesting that CBD acts independently of these targets in prostate cancer cells. Furthermore, CBD reduced the invasiveness of highly metastatic PC-3 cells and increased protein expression of E-cadherin. The ability of CBD to inhibit prostate cancer cell proliferation and invasiveness suggests that CBD may have potential as a future chemotherapeutic agent.

Verotoxin-producing Escherichia coli (VTEC) causes zoonotic infections, with potentially devastating complications, and children under 5 years old are particularly susceptible. Antibiotic treatment is contraindicated, and due to the high proportion of infected children that suffer from severe and life-changing complications, there is an unmet need for a vaccine to prevent VTEC infections. Bacterial adhesins represent promising candidates for the successful development of a vaccine against VTEC. Using a proteomic approach to identify bacterial proteins interacting with human gastrointestinal epithelial Caco-2 and HT-29 cells, we identified eleven proteins by mass spectrometry. These included a glutamine-binding periplasmic protein, GlnH, a member of the ABC transporter family. The glnH gene was identified in 13 of the 15 bovine and all 5 human patient samples tested, suggesting that it is prevalent. We confirmed that GlnH is involved in the host cell attachment of an O157:H7 prototype E. coli strain to gastrointestinal cells in vitro. Recombinant GlnH was expressed and purified prior to the immunisation of mice. When alum was used as an adjuvant, GlnH was highly immunogenic, stimulating strong serological responses in immunised mice, and it resulted in a modest reduction in faecal shedding but did not reduce colonisation. GlnH immunisation with a T-cell-inducing adjuvant (SAS) also showed comparable antibody responses and an IgG1/IgG2a ratio suggestive of a mixed Th1/Th2 response but was partially protective, with a 1.25-log reduction in colonisation of the colon and caecum at 7 days relative to the adjuvant only (p = 0.0280). It is clear that future VTEC vaccine developments should consider the contribution of adjuvants in addition to antigens. Moreover, it is likely that a combined cellular and humoral response may prove more beneficial in providing protective interventions against VTEC.

Introduction. Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria that cause severe bloody diarrhoea and haemolytic uraemic syndrome and are associated with neurological complications and potentially life-threatening infections. Children under five and elderly individuals are particularly vulnerable to STEC infections. The majority of STEC infections have been traced back directly or indirectly to ruminants, and there is an unmet need for a vaccine to protect these vulnerable cohorts. Gap Statement. We previously identified a series of STEC proteins that are involved in attachment to human gastrointestinal epithelial cells, some of which are protective in a murine challenge model. However, the prevalence of the genes in dairy herds was unknown. Aim. Due to zoonotic transmission, the development of a successful human vaccine relies on any protective vaccine antigens being prevalent in ruminant herds in different geographical locations. We aimed to examine the potential geographical differences in antigen gene prevalence. Methodology. Faecal isolates collected from a dairy herd in CA, USA, and isolated from dairy cows in Ireland were analysed by quantitative PCR. Bioinformatic analysis of previously sequenced isolates was also performed. Results. Four antigen genes were highly prevalent among STEC shed from cattle in a Californian dairy herd (>95.7%). Genes encoding FkpA, YiaF and GlnH were also highly prevalent in faecal samples from cows sampled in Ireland (93%). The point prevalence of terD among cattle in the Irish cohort appeared low relative to Californian isolates, but this is most likely due to the absence of tellurite in isolation media used in the former. Expansion of the study to examine Irish bovine and ovine Whole genome sequencing datasets increased the detection of terD in Irish isolates. Conclusion. Overall, three antigen genes are prevalent in both geographically distinct cohorts. Discrepancies in terD gene prevalence are likely due to the use of selective agars in isolation protocols.