Ras proteins as therapeutic targets

AZD4625 is a Potent and Selective Inhibitor of KRASG12C

AZD4625 is a potent, selective, and orally bioavailable inhibitor of oncogenic KRASG12C as demonstrated in cellular assays and in vivo in preclinical cell line-derived and patient-derived xenograft models. In vitro and cellular assays have shown selective binding and inhibition of the KRASG12C mutant isoform, which carries a glycine to cysteine mutation at residue 12, with no binding and inhibition of wild-type RAS or isoforms carrying non-KRASG12C mutations. The pharmacology of AZD4625 shows that it has the potential to provide therapeutic benefit to patients with KRASG12C mutant cancer as either a monotherapy treatment or in combination with other targeted drug agents.

The uptake of metal-organic frameworks: a journey into the cell

The application of metal-organic frameworks (MOFs) in drug delivery has advanced rapidly over the past decade, showing huge progress in the development of novel systems. Although a large number of versatile MOFs that can carry and release multiple compounds have been designed and tested, one of the main limitations to their translation to the clinic is the limited biological understanding of their interaction with cells and the way they penetrate them. This is a crucial aspect of drug delivery, as MOFs need to be able not only to enter into cells but also to release their cargo in the correct intracellular location. While small molecules can enter cells by passive diffusion, nanoparticles (NPs) usually require an energy-dependent process known as endocytosis. Importantly, the fate of NPs after being taken up by cells is dependent on the endocytic pathways they enter through. However, no general guidelines for MOF particle internalization have been established due to the inherent complexity of endocytosis as a mechanism, with several factors affecting cellular uptake, namely NP size and surface chemistry. In this review, we cover recent advances regarding the understanding of the mechanisms of uptake of nano-sized MOFs (nanoMOFs)s, their journey inside the cell, and the importance of biological context in their final fate. We examine critically the impact of MOF physicochemical properties on intracellular trafficking and successful cargo delivery. Finally, we highlight key unanswered questions on the topic and discuss the future of the field and the next steps for nanoMOFs as drug delivery systems.

KRASG12C inhibitor: combing for combination

Oncogenic mutation in KRAS is one of the most common alterations in human cancer. After decades of extensive research and unsuccessful drug discovery programs, therapeutic targeting of KRAS mutant tumour is at an exciting juncture. The discovery of mutation-specific inhibitors of KRASG12C and early positive findings from clinical trials has raised the hope of finally having a drug to treat a significant segment of KRAS mutant cancer patients. Crucially, it has also re-energized the RAS field to look beyond G12C mutation and find new innovative targeting opportunities. However, the early clinical trial data also indicates that there is significant variation in response among patients and that monotherapy treatment with KRASG12C inhibitors (G12Ci) alone is unlikely to be sufficient to elicit a sustained response. Understanding the molecular mechanism of variation in patient response and identifying possible combination opportunities, which could be exploited to achieve durable and significant responses and delay emergence of resistance, is central to the success of G12Ci therapy. Given the specificity of G12Ci, toxicity is expected to be minimal. Therefore, it might be possible to combine G12Ci with other targeted agents which have previously been explored to tackle KRAS mutant cancer but deemed too toxic, e.g. MEK inhibitor. Ongoing clinical trials will shed light on clinical resistance to G12C inhibitors, however extensive work is already ongoing to identify the best combination partners. This review provides an update on combination opportunities which could be explored to maximize the benefit of this new exciting drug.

The discovery and maturation of peptide biologics targeting the small G-protein Cdc42: A bioblockade for Ras-driven signaling

Aberrant Ras signaling drives 30% of cancers, and inhibition of the Rho family small GTPase signaling has been shown to combat Ras-driven cancers. Here, we present the discovery of a 16-mer cyclic peptide that binds to Cdc42 with nanomolar affinity. Affinity maturation of this sequence has produced a panel of derived candidates with increased affinity and modulated specificity for other closely-related small GTPases. The structure of the tightest binding peptide was solved by NMR, and its binding site on Cdc42 was determined. Addition of a cell-penetrating sequence allowed the peptides to access the cell interior and engage with their target(s), modulating signaling pathways. In Ras-driven cancer cell models, the peptides have an inhibitory effect on proliferation and show suppression of both invasion and motility. As such, they represent promising candidates for Rho-family small GTPase inhibitors and therapeutics targeting Ras-driven cancers. Our data add to the growing literature demonstrating that peptides are establishing their place in the biologics arm of drug discovery.