Advancement of targeted protein degradation strategies as therapeutics for undruggable disease targets

Orally Bioavailable Proteolysis-Targeting Chimeras: An Innovative Approach in the Golden Era of Discovering Small-Molecule Cancer Drugs

Proteolysis-targeting chimeras (PROTACs) are an emerging therapeutic modality that show promise to open a target space not accessible to conventional small molecules via a degradation-based mechanism. PROTAC degraders, due to their bifunctional nature, which is categorized as 'beyond the Rule of Five', have gained attention as a distinctive therapeutic approach for oral administration in clinical settings. However, the development of PROTACs with adequate oral bioavailability remains a significant hurdle, largely due to their large size and less than ideal physical and chemical properties. This review encapsulates the latest advancements in orally delivered PROTACs that have entered clinical evaluation as well as developments highlighted in recent scholarly articles. The insights and methodologies elaborated upon in this review could be instrumental in supporting the discovery and refinement of novel PROTAC degraders aimed at the treatment of various human cancers.

Identification of a Sonically Activated Degrader of Methionine Adenosyltransferase 2A by an in Silico Approach Assisted with the Hole-Electron Analysis

Small molecules capable of modulating methionine adenosyltransferase 2A (MAT2A) are of significant interest in precise cancer therapeutics. Herein, we raised the hole-electron Coulombic attraction as a reliable molecular descriptor for predicting the reactive oxygen generation capacity of MAT2A inhibitors, based on which we discovered compound H3 as a sonically activated degrader of MAT2A. Upon sonication, H3 can generate reactive oxygen species to specifically degrade cellular MAT2A via rapid oxidative reactions. Combination of H3 and sonication induced 87% MAT2A depletion in human colon cancer cells, thus elevating its antiproliferation effects by 8-folds. In vivo, H3 had a favorable pharmacokinetic profile (bioavailability = 77%) and ADME properties. Owing to the MAT2A degradation merits, H3 at a dosage of 10 mg/kg induced 31% tumor regression in xenograft colon tumor models. The significantly boosted antitumor potency can potentially alleviate the toxicity of high-dose MAT2A inhibitors to normal cells and tissues, especially to the liver.

Current advances and development strategies of orally bioavailable PROTACs

Proteolysis-targeting chimeras (PROTACs) have been an area of intensive research with the potential to extend drug space not target to traditional molecules. In the last half decade, we have witnessed several PROTACs initiated phase I/II/III clinical trials, which inspired us a lot. However, the structure of PROTACs beyond "rule of 5" resulted in developing PROTACs with acceptable oral pharmacokinetic (PK) properties remain one of the biggest bottleneck tasks. Many reports have demonstrated that it is possible to access orally bioavailable PROTACs through rational ligand and linker modifications. In this review, we systematically reviewed and highlighted the most recent advances in orally bioavailable PROTACs development, especially focused on the medicinal chemistry campaign of discovery process and in vivo oral PK properties. Moreover, the constructive strategies for developing oral PROTACs were proposed comprehensively. Collectively, we believe that the strategies summarized here may provide references for further development of oral PROTACs.

Unveiling Potential Targeted Therapeutic Opportunities for Co-Overexpressed Targeting Protein for Xklp2 and Aurora-A Kinase in Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is one of the most prevalent and leading causes of cancer deaths globally, with limited diagnostic and clinically significant therapeutic targets. Identifying the genes and processes involved in developing and progressing LUAD is crucial for developing effective targeted therapeutics and improving patient outcomes. Therefore, the study aimed to explore the RNA sequencing data of LUAD from The Cancer Genome Atlas (TCGA) and gene expression profile datasets involving GSE10072, GSE31210, and GSE32863 from the Gene Expression Omnibus (GEO) databases. The differential gene expression and the downstream analysis determined clinically significant biomarkers using a network-based approach. These therapeutic targets predominantly enriched the dysregulation of mitotic cell cycle regulation and revealed the co-overexpression of Aurora-A Kinase (AURKA) and Targeting Protein for Xklp2 (TPX2) with high survival risk in LUAD patients. The hydrophobic residues of the AURKA-TPX2 interaction were considered as the target site to block the autophosphorylation of AURKA during the mitotic cell cycle. The tyrosine kinase inhibitor (TKI) dacomitinib demonstrated the strong binding potential to hinder TPX2, shielding the AURKA destabilization. This in silico study lays the foundation for repurposing targeted therapeutic options to impede the Protein-Protein Interactions (PPIs) in LUAD progression and aid in future translational investigations.