Factors regulating the production of STX-2 in Escherichia coli O157:H7

The severity of Escherichia coli O157:H7 disease is due in part to a major virulence factor produced by the microbe, the shiga-like toxin 2 (Stx-2). Antibiotic treatment to reduce pathogen numbers is controversial, as it is thought that antibiotics may increase the levels of Stx-2 released from the pathogen. Currently, recommended treatment for E. coli O157:H7 is palliative The purpose of this study was to examine three critical factors potentially important to disease outcomes, and to determine their effect on expression of the stx2 gene and on release of Stx-2 from the pathogen. Those factors selected for study were: (i) various classes of antibiotics; (ii) probiotic microorganisms; and (iii) carbon source variation together with cAMP. Stx-2 was assessed using MTT cytotoxicity assays and ELISA analysis, while the expression of stx2 was assessed using real time PCR. It was determined that antibiotics that affect microbial DNA increased stx2 expression and Stx-2 production, and this was linked to an upregulation in the SOS DNA repair response. A link was also observed between the upregulation of stx2 and those antibiotics that disrupt cell membrane integrity. However, these antibiotics did not increase the overall levels of Stx-2 released from E. coli O157:H7. The probiotic microorganisms Lactobacillus casei and L. plantarum were found to decrease both stx2 expression and Stx-2 release when grown in co-culture with E. coli O157:H7 at greater or equal numbers to the pathogen. This reduction in Stx-2 was at least in part attributable to organic acids produced by the probiotics, but other unknown factors produced by the lactobacilli cannot be excluded. Finally, it was determined that growth of the pathogen in glucose-supplemented media yielded significantly more stx2 expression and Stx-2 production than growth in glycerol-supplemented media. This observation was confirmed by a decrease in stx2 expression and Stx-2 production when exogenous cAMP was added to culture media. The examination of these three factors led to a clearer understanding of the intricacies involved in the regulation of stx2, and has demonstrated how such an apparently diverse group of external factors are interlinked through several complex mechanisms

AI is a viable alternative to high throughput screening: a 318-target study

: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Fighting Cancer around the World: A Framework for Action

Tackling cancer is a major challenge right on the global level. Europe is only the tip of an iceberg of cancer around the world. Prosperous developed countries share the same problems besetting Europe&ndash;and the countries and regions with fewer resources and less propitious conditions are in many cases struggling often heroically against a growing tide of disease. This paper offers a view on these geographically wider, but essentially similar, challenges, and on the prospects for and barriers to better results in this ceaseless battle. A series of panels have been organized by the European Alliance for Personalised Medicine (EAPM) to identify different aspects of cancer care around the globe. There is significant diversity in key issues such as NGS, RWE, molecular diagnostics, and reimbursement in different regions. In all, it leads to disparities in access and diagnostics, patients&rsquo; engagement, and efforts for a better understanding of cancer

The Serological Sciences Network (SeroNet) for COVID-19: Depth and Breadth of Serology Assays and Plans for Assay Harmonization.

In October 2020, the National Cancer Institute (NCI) Serological Sciences Network (SeroNet) was established to study the immune response to COVID-19, and "to develop, validate, improve, and implement serological testing and associated technologies" (https://www.cancer.gov/research/key-initiatives/covid-19/coronavirus-research-initiatives/serological-sciences-network). SeroNet is comprised of 25 participating research institutions partnering with the Frederick National Laboratory for Cancer Research (FNLCR) and the SeroNet Coordinating Center. Since its inception, SeroNet has supported collaborative development and sharing of COVID-19 serological assay procedures and has set forth plans for assay harmonization. To facilitate collaboration and procedure sharing, a detailed survey was sent to collate comprehensive assay details and performance metrics on COVID-19 serological assays within SeroNet. In addition, FNLCR established a protocol to calibrate SeroNet serological assays to reference standards, such as the U.S. severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology standard reference material and first WHO international standard (IS) for anti-SARS-CoV-2 immunoglobulin (20/136), to facilitate harmonization of assay reporting units and cross-comparison of study data. SeroNet institutions reported development of a total of 27 enzyme-linked immunosorbent assay (ELISA) methods, 13 multiplex assays, and 9 neutralization assays and use of 12 different commercial serological methods. FNLCR developed a standardized protocol for SeroNet institutions to calibrate these diverse serological assays to reference standards. In conclusion, SeroNet institutions have established a diverse array of COVID-19 serological assays to study the immune response to SARS-CoV-2 and vaccines. Calibration of SeroNet serological assays to harmonize results reporting will facilitate future pooled data analyses and study cross-comparisons. IMPORTANCE SeroNet institutions have developed or implemented 61 diverse COVID-19 serological assays and are collaboratively working to harmonize these assays using reference materials to establish standardized reporting units. This will facilitate clinical interpretation of serology results and cross-comparison of research data