A Mega-High-Throughput Screening Platform for the Discovery of Biologically Relevant Sequence-Defined Non-Natural Polymers

Combinatorial methods enable the synthesis of chemical libraries on scales of millions to billions of compounds, but the ability to efficiently screen and sequence such large libraries has remained a major bottleneck for molecular discovery. We developed a novel technology for screening and sequencing libraries of synthetic molecules of up to a billion compounds in size. This platform utilizes the Fiber-optic Array Scanning Technology (FAST) to screen bead-based libraries of synthetic compounds at a rate of 5 million compounds per minute (~83,000 Hz). This ultra-high-throughput screening platform has been used to screen libraries of synthetic “self-readable” non-natural polymers that can be sequenced at femtomole scale by chemical fragmentation and high-resolution mass spectrometry. The versatility and throughput of the platform was demonstrated by screening two libraries of non-natural polyamide polymers with sizes of 1.77M and 1B compounds against the protein targets K-Ras, asialoglycoprotein receptor 1 (ASGPR), IL-6, IL 6 receptor (IL-6R) and TNFα. Hits with low nanomolar binding affinities were found against all targets, including competitive inhibitors of K-Ras binding to Raf and functionally active uptake ligands for ASGPR facilitating intracellular delivery of a non-glycan ligand

Discovery and Optimization of Benzotriazine Di-<i>N</i>-Oxides Targeting Replicating and Nonreplicating Mycobacterium tuberculosis

Compounds bactericidal against both replicating and nonreplicating Mtb may shorten the length of TB treatment regimens by eliminating infections more rapidly. Screening of a panel of antimicrobial and anticancer drug classes that are bioreduced into cytotoxic species revealed that 1,2,4-benzotriazine di-<i>N</i>-oxides (BTOs) are potently bactericidal against replicating and nonreplicating Mtb. Medicinal chemistry optimization, guided by semiempirical molecular orbital calculations, identified a new lead compound (<b>20q</b>) from this series with an MIC of 0.31 μg/mL against H37Rv and a cytotoxicity (CC₅₀) against Vero cells of 25 μg/mL. <b>20q</b> also had equivalent potency against a panel of single-drug resistant strains of Mtb and remarkably selective activity for Mtb over a panel of other pathogenic bacterial strains. <b>20q</b> was also negative in a L5178Y MOLY assay, indicating low potential for genetic toxicity. These data along with measurements of the physiochemical properties and pharmacokinetic profile demonstrate that BTOs have the potential to be developed into a new class of antitubercular drugs