Structure-Activity Relationship Studies Enable Optimization of a Small-Molecule Autophagy Activator and Evaluation of Effects on Cell Death Pathways.

Autophagy is a catabolic cellular process that degrades and recycles cellular components. Dysregulation of autophagy can contribute to the development and progression of many different diseases, including cancer and neurodegenerative diseases. Our lab previously completed a high-throughput screen for autophagy activators, and initial structure-activity relationship studies revealed modifications that significantly increased the potency of the original hit. However, this compound has very poor microsomal stability, limiting its utility as an in vivo probe. To overcome this limitation, we developed synthetic strategies to facilitate iterative synthesis of additional analogues with improved potency, stability, and properties. Mechanistic studies revealed that high levels of sustained autophagy activation can lead to autophagy-dependent cell death and enabled differentiation of analogues with off-target effects and analogues with improved selectivity. The most promising analogues have been selected for additional evaluation in disease-relevant models to improve our understanding of the role of autophagy in diverse disease states.