Dose–Response Activity-Based DNA-Encoded Library Screening

[Image: see text] Dose–response, or “conforming” behavior, increases confidence in a screening hit’s authenticity. Here, we demonstrate dose–response solid-phase DNA-encoded library (DEL) screening. Compound dose in microfluidic droplets is modulated via the UV intensity of photocleavage from DEL beads. A 55,296-member DEL was screened at different UV intensities against model enzyme drug targets factor Xa (FXa) and autotaxin (ATX). Both screens yielded photochemical dose-dependent hit rates (FXa hit rates of 0.08/0.05% at 100/30% UV exposure; ATX hit rates of 0.24/0.08% at 100/20% UV exposure). FXa hits contained structures reflective of FXa inhibitors and four hits inhibited FXa (IC(50) = 4.2 ± 0.1, 7.4 ± 0.3, 9.0 ± 0.3, and 19 ± 2 μM.) The top ATX hits (two dihydrobenzamidazolones and a tetrahydroisoquinoline) were validated as inhibitors (IC(50) = 7 ± 2, 13 ± 2, and 1 ± 0.3 μM). Photochemical dose–response DEL screening data prioritized hits for synthesis, the rate-limiting step in DEL lead identification.