ABSTRACT
Here we present the rational design and synthetic methodologies towards proteolysis-targeting chimeras (PROTACs) for the recently-emerged target leucine-rich repeat kinase 2 (LRRK2). Two highly potent, selective, brain-penetrating kinase inhibitors were selected, and their structure was appropriately modified to assemble a cereblon-targeting PROTAC. Biological data show strong kinase inhibition and the ability of the synthesized compounds to enter the cells. However, data regarding the degradation of the target protein are inconclusive. The reasons for the inefficient degradation of the target are further discussed.
Subject(s)
Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Pyrimidines/pharmacology , Pyrroles/pharmacology , HEK293 Cells , Humans , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/metabolism , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Proteolysis/drug effects , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Pyrroles/chemical synthesis , Pyrroles/chemistryABSTRACT
Introduction: Proteolysis - targeting chimeras (PROTACs) have emerged as a new modality with the potential to revolutionize drug discovery. PROTACs are heterobifunctional molecules comprising of a ligand targeting a protein of interest, a ligand targeting an E3 ligase and a connecting linker. The aim is instead of inhibiting the target to induce its proteasomal degradation. Areas covered: PROTACs, due to their bifunctional design, possess properties that differentiate them from classical inhibitors. A structural analysis, based on published crystal aspects, kinetic features and aspects of selectivity are discussed. Specific types such as homoPROTACs, PROTACs targeting Tau protein and the first PROTACs recently entering clinical trials are examined. Expert opinion: PROTACs have shown remarkable biological responses in challenging targets, including an unprecedented selectivity over protein family members and even efficacy starting from weak or unspecific binders. Moreover, PROTACs are standing out from classical pharmacology by inducing the degradation of the target protein and not merely its inhibition. However, there are also challenges in the field, such as the rational structure optimization, the evolution of computational tools, limited structural data and the greatly anticipated clinical data. Despite the remaining hurdles, PROTACs are expected to soon become a new therapeutic category of drugs.
