SyntheX uses synthetic biology to create the next generation of drug discovery platforms to modulate protein-protein interactions (PPIs). Using genetically engineered circuits, our platform technology relies on intracellular drug selection as opposed to in vitro screening. This allows us to discover compounds with novel modes of action that can engage targets not just in orthosteric but also in allosteric manners. We have developed ToRPPIDO to discover disruptors of PPIs, and ToRNeDO to discover functional protein degraders that are capable of inducing proximity between a ubiquitin E3 ligase and a neosubstrate of interest. The platforms are compatible with multiple chemical matter modalities. We have successfully performed multiple screens with our in-house proprietary DNA encoded peptide and macrocycle libraries, and have additionally established the amenability of our platforms to high-throughput small molecule screening (HTS).

Our lead program, STX100, is a stabilized peptide that targets an intracellular PPI within the homologous recombination (HR) DNA repair pathway. Work on this program led us to discover and characterize a new immunogenic cell death mechanism that exploits the differential abundance of the HR target in cancer cells relative to normal tissue. Upon binding to its target, STX100 elicits an acute calcium-dependent cell death in over 30 different cancer cell lines but not in primary cells. STX100 exhibits in-vivo efficacy in multiple tumor types and potentiates the activity of immune-checkpoint blockade (ICB) therapies in multiple ICB-recalcitrant syngeneic models.

Nucleoside/tide analogs have played a key role in the treatment of viral infections caused by DNA viruses such as herpes virus and hepatitis B virus, as well as RNA viruses such as human immunodeficiency virus (HIV), hepatitis C virus (HCV), influenza virus, and most recently the coronavirus SARS-CoV-2, the pathogen causing the COVID-19 pandemic. Studies over the past several decades have significantly expanded our knowledge on the potential off-target effects for this class of compounds, including inhibition of host nucleic acid polymerases such as human mitochondrial DNA polymerase γ (POL γ) and mitochondrial RNA polymerase (POLRMT) as well as perturbation of nucleotide metabolism, mitochondrial respiration, and dNTP/NTP pools. Importantly, suitable methods to evaluate the potential for these types of toxicities are currently available. This presentation will provide a historical review of the discovery of safe and efficacious antiviral nucleoside/tide analogs and lessons learned from failed clinical studies due to safety concerns. We will also discuss the utility of a panel of biochemical and cell-based assays to assess toxicity-liability in the early drug discovery stage.

Sickle cell disease is considered an orphan disease in the United States, but affects millions of people world‐wide, primarily in sub-Saharan Africa and India. The molecular basis for the disease is a point mutation on the gene that codes for the beta‐strands of hemoglobin. In the 1990s, the first and only anti‐sickling drug, hydroxyurea, was approved by the FDA.
Hydroxyurea induces the production of fetal hemoglobin, which dilutes sickle hemogoblin and slows or prevents hemoglobin aggregation upon deoxygenation. However, hydroxyurea only works for a portion of those affected by sickle cell disease and can come with many severe side effects. At NIH, colleagues have found that –about 10% of sickle cell patients can be cured by stem cell transplantation, but an inexpensive drug that can be given orally and distributed worldwide is needed.

Over the past couple of years, research initiatives at the Eaton group have led to development of a high‐throughput drug screen that is currently being used to test a library of 12,000+ compounds that have previously been tested in humans. Drug repurposing is the highest priority, as it provides the quickest route from the lab to sickle cell disease patients. The assay depends on having an understanding of the underlying cause of the disease‐damaged, deoxygenated red blood cells that block the microcirculation and cause organ damage. Increasing the delay time between deoxygenation and sickling makes the disease survivable. In the drug screen workflow, a brightfield microscope is used to collect images of sickle red blood cells as a function of time after deoxygenation in the absence and presence of compounds in the test library. A machine learning algorithm identifies sickled cells based on differences in cellular properties such as morphology and optical density between unsickled and sickled cells. Any compound that increases the delay time prior to sickling or inhibits overall sickling compared to the control is considered a hit, and if the compound is known to be non‐toxic to humans, it may be immediately moved into research clinical trials at NIH.

 For Research Use Only. Not for use in diagnostic procedures.

Presentation Abstract: Among the major challenges in the development of biopharmaceuticals are structural heterogeneity and aggregation. The development of a successful therapeutic monoclonal antibody (mAb) requires both a highly active and also stable molecule. Whilst a range of experimental (biophysical) approaches exist to track changes in stability of proteins, routine prediction of stability remains challenging. The fluorescence red edge excitation shift (REES) phenomenon is sensitive to a range of changes in protein structure. Based on recent work, we have found that quantifying the REES effect is extremely sensitive to changes in protein conformational state and dynamics. Given the extreme sensitivity, potentially this tool could provide a ‘fingerprint’ of the structure and stability of a protein. Such a tool would be useful in the discovery and development of biopharmaceuticals and so we have explored our hypothesis with a panel of therapeutic mAbs. We demonstrate that the quantified REES data, which we call QUBES, show remarkable sensitivity, being able to discern between structurally identical antibodies and showing sensitivity to unfolding and aggregation. The approach works across a broad concentration range (μg –mg/ml) and is highly consistent. We show that the approach can be applied alongside traditional characterisation testing within the context of a forced degradation study (FDS). Most importantly, we demonstrate the approach is able to predict the stability of mAbs both in the short (hours), medium (days) and long-term (months). The QUBES data will find immediate use in the biopharmaceutical industry in quality assurance, formulation and development. The approach benefits from low technical complexity, is rapid and uses instrumentation which exists in most biochemistry laboratories without modification. Moreover, we illustrate the approach can be optimally used on a commercially available plate reader.

For Research Use Only. Not for use in diagnostic procedures.
 

In this webinar, Dr. Victor Darley-Usmar will introduce a new concept known as the bioenergetic-metabolite interactome, which describes how defining our bioenergetic health at the level of individual cells can now be achieved. Although we have known that our metabolism and how we use energy must reflect our response as individuals, until recently it has been very difficult to show this works in human subjects. An interesting and surprising aspect of this work was to show that the molecules we are exposed to (the exposome) can have a direct and quantitative impact on our metabolism which varies between people. These studies are in the early stages but emerging in parallel to interesting and new ways to control our metabolism as a preventative strategy for the diseases associated with healthy aging.

In this webinar, Dr. Sandra Milasta, Senior Scientist of Elevatebio will discuss how metabolic pathways maintain lymphocyte survival, drive memory vs. effector function, and the implications of these findings on the development of next generation T cell-based therapies. There has been growing interest in the field of immunotherapy to understand if we can shape the T cell response by targeting T cell metabolism.