Dose-Response Activity-Based DNA-Encoded Library Screening

Dose-response, or "conforming" behavior,increasesconfidence in a screening hit's authenticity. Here, we demonstratedose-response solid-phase DNA-encoded library (DEL) screening.Compound dose in microfluidic droplets is modulated via the UV intensityof photocleavage from DEL beads. A 55,296-member DEL was screenedat different UV intensities against model enzyme drug targets factorXa (FXa) and autotaxin (ATX). Both screens yielded photochemical dose-dependenthit rates (FXa hit rates of 0.08/0.05% at 100/30% UV exposure; ATXhit rates of 0.24/0.08% at 100/20% UV exposure). FXa hits containedstructures reflective of FXa inhibitors and four hits inhibited FXa(IC50 = 4.2 & PLUSMN; 0.1, 7.4 & PLUSMN; 0.3, 9.0 & PLUSMN; 0.3,and 19 & PLUSMN; 2 & mu;M.) The top ATX hits (two dihydrobenzamidazolonesand a tetrahydroisoquinoline) were validated as inhibitors (IC50 = 7 & PLUSMN; 2, 13 & PLUSMN; 2, and 1 & PLUSMN; 0.3 & mu;M). Photochemicaldose-response DEL screening data prioritized hits for synthesis,the rate-limiting step in DEL lead identification.