Targeted protein degradation, through the use of heterobifunctional degraders that act as catalytic activators for an E3 ligase and target protein ubiquitination event, have the potential to transform drug discovery. This seminar will focus on in vitro to in vivo correlation, oral bioavailability, as well as initial insights into likely drivers of these two key parameters of drug discovery.

Inhibition of Bromodomain-containing proteins, such as BET and SMARCA2, is being evaluated as a therapeutic strategy in cancer. While these inhibitors affect only the reader function of these proteins, their degradation causes a global assembly defect, leading to anti-proliferative activity. Here, we present the discovery of lower molecular weight, orally bioavailable and efficacious degraders of Bromodomain-containing targets using our proprietary ALMOND (ALgorithm for Modelling Neosubstrate Degraders) technology.

The CETSA MS profiling of degraders allow simultaneous study of both direct binding both its intended protein target, involved E3-ligase and potential off-targets.  In this talk we will present recent CETSA MS profiles on both protacs and molecular glue molecules in living cells including the degradation specificity and efficacy.

Targeted protein degradation using bifunctional molecules to remove specific proteins by hijacking the ubiquitin proteasome system has emerged as a novel drug discovery approach. Several challenges remain in designing optimal degraders that also show efficacy in vivo. We will present case studies from our ongoing efforts in the design and biological evaluation of novel degraders that are orally active in mouse xenograft models.

Bcl-xL plays a key role in cancer cell survival. However, development of drugs targeting Bcl-xL has been thwarted by the on-target platelet toxicity because platelets depend on Bcl-xL to maintain their viability. To circumvent this toxicity, we have applied the proteolysis targeting chimera (PROTAC) technology to design small-molecules that target Bcl-xL to E3 ligases for degradation. This proof-of-concept study demonstrates the potential of utilizing a PROTAC approach to achieve tissue selectivity.

Eurofins Discovery will present how the novel E3scan™ technology has been applied to diverse E3 ligases, including CRBN, VHL, MDM2, MDMX, cIAP1, cIAP2, and XIAP. We will also present how engineered biosensor cell lines employing gene editing with CRISPR/Cas9 and our well-established EFC technology will enable sensitive quantitation of PROTAC-mediated degradation of the target of interest in physiologically relevant cell models using a homogeneous assay format.

The PROTAC field is at its infancy. Only the well-known ligases (Cereblon, VHL, HDM2, and cIAPs) have been exploited by medicinal chemists. Too many resources are devoted to these ligases as vehicles for PROTACs. Progenra has focused its attention to novel ubiquitin ligases and discovered an entirely new class of PROTACs. We have validated applications of novel ligases by designing PROTACs with promiscuous kinase inhibitor that degrades a number of kinases not degraded by traditional ligase PROTACs. Kinetics and dose response has established their application in oncology, inflammatory, and neuroscience.

Two major principles of targeting the ubiquitin system have emerged: direct targeting of the enzymes that control protein ubiquitination and hijacking E3 ligases to induce protein degradation. In this lecture, I will outline the discovery of novel probes, UbFluor, cross-linking reagents, and kinase targeting PROTACs to discover small molecule inhibitors/activators and hijackers for Cullin-RING/RBR/HECT E3 ligases. 

While several irreversible PROTACs have been developed, the effect of irreversible binding on degradation efficiency is still unclear. We designed a reversible covalent binding PROTAC against BTK, aiming to take advantage of both the potency of the covalent binding, as well as the catalytic efficiency stemming from reversibility. We show, that while such a reversible covalent PROTAC can work, optimizing target engagement, might be more important than reversibility. The general approach can guide the design of reversible covalent PROTACs for a variety of targets, and the insights on affinity/reversibility trade-off can inform future PROTAC design. I will also briefly present PRosettaC, a computational pipeline for the modeling of PROTAC mediated quaternary complexes. 

Small molecules that induce protein degradation through ligase-mediated ubiquitination, have shown considerable promise as a new pharmacological modality. Thalidomide and related IMiDs provided the clinical proof of concept, while significant progress has recently been made towards chemically induced targeted protein degradation using heterobifunctional small molecule ligands. We will present recent work towards a better understanding of the molecular principles that govern neo-substrate recruitment, and other small molecule degraders.

CRELUX, is an integral part of the WuXi AppTec Research Services Division (RSD). We deliver tailored solutions in structure-based drug discovery. By screening our proprietary fragment library using powerful biophysical techniques such as MST, SPR or nanoDSF we successfully support clients already in early stage drug discovery campaigns

New modalities, such as PROTACs, are powerful tools that allow biology assessment of oncogenic targets beyond the conventional kinase inhibition. Focal Adhesion Kinase (FAK) is a key mediator of tumour progression and is overexpressed in many solid tumours; to date, inhibitors targeting FAK kinase activity have shown low success in the clinic. Here, we report the design and characterization of a highly potent FAK degrader with increased efficacy over FAK inhibitor, as well as extended in vivo efficacy.

PROTACs are bifunctional molecules, designed to bind with target protein and E3 ligase to degrade target protein by hijacking cell’s own ubiquitin proteasome system. PROTACs have several advantages but challenges remain in designing optimal PROTACs that has acceptable absorption, distribution, metabolism and excretion (ADME) properties to demonstrate efficacy in vivo. Literature published PROTACs have high MW (beyond rule of 5), low permeability and low oral bioavailability. This presentation will focus on ADME properties of PROTACs with special focus on strategy to improve oral bioavailability.