The growing resistance to current first-line antimalarial drugs represents a major health challenge. To facilitate the discovery of new antimalarials, we have implemented an efficient and robust highthroughput cell-based screen (1,536-well format) based on proliferation of Plasmodium falciparum (Pf) in erythrocytes. From a screen of Ϸ1.7 million compounds, we identified a diverse collection of Ϸ6,000 small molecules comprised of >530 distinct scaffolds, all of which show potent antimalarial activity (<1.25 M). Most known antimalarials were identified in this screen, thus validating our approach. In addition, we identified many novel chemical scaffolds, which likely act through both known and novel pathways. We further show that in some cases the mechanism of action of these antimalarials can be determined by in silico compound activity profiling. This method uses large datasets from unrelated cellular and biochemical screens and the guilt-by-association principle to predict which cellular pathway and/or protein target is being inhibited by select compounds. In addition, the screening method has the potential to provide the malaria community with many new starting points for the development of biological probes and drugs with novel antiparasitic activities.antifolates ͉ cheminformatics ͉ high-throughput screening ͉ Plasmodium falciparum

Insufficient pancreatic β-cell mass or function results in diabetes mellitus. While significant progress has been made in regulating insulin secretion from β-cells in diabetic patients, no pharmacological agents have been described that increase β-cell replication in humans. Here we report aminopyrazine compounds that stimulate robust β-cell proliferation in adult primary islets, most likely as a result of combined inhibition of DYRK1A and GSK3B. Aminopyrazine-treated human islets retain functionality in vitro and after transplantation into diabetic mice. Oral dosing of these compounds in diabetic mice induces β-cell proliferation, increases β-cell mass and insulin content, and improves glycaemic control. Biochemical, genetic and cell biology data point to Dyrk1a as the key molecular target. This study supports the feasibility of treating diabetes with an oral therapy to restore β-cell mass, and highlights a tractable pathway for future drug discovery efforts.

Chemotherapies are known often to induce severe gastrointestinal tract toxicity but the underlying mechanism remains unclear. This study considers the widely applied cytotoxic agent irinotecan (CPT-11) as a representative agent and demonstrates that treatment induces massive release of double-strand DNA from the intestine that accounts for the dose-limiting intestinal toxicity of the compound. Specifically, "self-DNA" released through exosome secretion enters the cytosol of innate immune cells and activates the AIM2 (absent in melanoma 2) inflammasome. This leads to mature IL-1β and IL-18 secretion and induces intestinal mucositis and late-onset diarrhoea. Interestingly, abrogation of AIM2 signalling, either in AIM2-deficient mice or by a pharmacological inhibitor such as thalidomide, significantly reduces the incidence of drug-induced diarrhoea without affecting the anticancer efficacy of CPT-11. These findings provide mechanistic insights into how chemotherapy triggers innate immune responses causing intestinal toxicity, and reveal new chemotherapy regimens that maintain anti-tumour effects but circumvent the associated adverse inflammatory response.

Rapid quantitative methods for characterizing small molecules, peptides, proteins, or RNAs in a broad array of cellular assays would allow one to discover new biological activities associated with these molecules and also provide a more comprehensive profile of drug candidates early in the drug development process. Here we describe a robotic system, termed the automated compound profiler, capable of both propagating a large number of cell lines in parallel and assaying large collections of molecules simultaneously against a matrix of cellular assays in a highly reproducible manner. To illustrate its utility, we have characterized a set of 1,400 kinase inhibitors in a panel of 35 activated tyrosine-kinasedependent cellular assays in dose-response format in a single experiment. Analysis of the resulting multidimensional dataset revealed subclusters of both inhibitors and kinases with closely correlated activities. The approach also identified activities for the p38 inhibitor BIRB796 and the dual src͞abl inhibitor BMS-354825 and exposed the expected side activities for Glivec͞STI571, including cellular inhibition of c-kit and platelet-derived growth factor receptor. This methodology provides a powerful tool for unraveling the cellular biology and molecular pharmacology of both naturally occurring and synthetic chemical diversity.drug discovery ͉ high-throughput screening ͉ tyrosine kinase T he ability to simultaneously interrogate the activities of a library of molecules against a large panel of cellular assays would provide a rapid efficient means to begin to characterize and correlate the biological properties of both natural and synthetic chemical diversity. For example, libraries of noncoding RNAs, mutant growth factors, small molecule kinase inhibitors, or even existing drugs could be assayed for their potency and selectivity in pathway-based or receptor screens or toxicity and metabolic stability in diverse cell types to discover a new biological activity or optimize the pharmacological properties of a molecule (1-3). Although whole-cell systems represent an attractive milieu to characterize gene and small-molecule function, no robust and systematic method exists to correlate chemical structure and biological activity across a large number of molecules and cellular assays. To address this problem, we have developed an approach that affords rapid cost-effective broad-based cellular profiling in parallel against molecular libraries. An industrial-scale automated compound profiling (ACP) system has been designed, which consists of an automated tissue culture system for propagating cell lines, integrated with a system for automatically performing miniaturized cell-based assays in 384-or 1,536-well microplates. The ACP can rapidly test thousands of arrayed molecules, in replicates, in doseresponse format against hundreds of unique cellular assays in a single experiment.To demonstrate this capability, we focused on the problem of identifying selective small-molecule inhibitors of protein tyrosine kinases. Tyrosine ...