Stuart Schreiber (born February 6, 1956) is an American chemist who is the Morris Loeb Research Professor at Harvard University, a co-founder of the Broad Institute, Howard Hughes Medical Institute Investigator, Emeritus, and a member of the National Academy of Sciences and National Academy of Medicine. He currently leads Arena BioWorks.
His work integrates chemical biology and human biology to advance the science of therapeutics. Key advances include the discovery that small molecules can function as “molecular glues” that promote protein–protein interactions, the co-discovery of mTOR and its role in nutrient-response signaling, the discovery of histone deacetylases and (with Michael Grunstein and David Allis) the demonstration that chromatin marks regulate gene expression, the development and application of diversity-oriented synthesis to microbial therapeutics, and the discovery of vulnerabilities of cancer cells linked to genetic, lineage and cell-state features, including ferroptotic vulnerabilities. His awards include the Wolf Prize in Chemistry and the Arthur Cope Award. His approach to discovering new therapeutics guided many biotechnology companies that he founded, including Vertex Pharmaceuticals and Ariad Pharmaceuticals. He has founded or co-founded 14 biotechnology companies, which have developed 16 first-in-human approved drugs or advanced clinical candidates.
Schreiber attended Luther Jackson Junior High School in Falls Church, VA and graduated from Oakton High School in Fairfax, VA in 1973 after completing a 3-year work study program that prepared him for work in the construction field.
Following his work on the FK506-binding protein FKBP in 1988, Schreiber reported that the small molecules FK506 and cyclosporin inhibit the activity of the phosphatase calcineurin by forming the ternary complexes FKBP12-FK506-calcineurin and cyclophilin-ciclosporin-calcineurin. This work, together with work by Gerald Crabtree at Stanford University concerning the NFAT proteins, led to the elucidation of the calcium-calcineurin-NFAT signaling pathway. The Ras-Raf-MAPK pathway was not elucidated for another year.
In 1993, Schreiber and Crabtree developed bifunctional molecules or “chemical inducers of proximity” (CIPs), which provide small-molecule activation over numerous signaling molecules and pathways (e.g., the Fas, insulin, TGFβ and T-cell receptors) through proximity effects. Schreiber and Crabtree demonstrated that small molecules could activate a signaling pathway in an animal with temporal and spatial control."Functional Analysis of Fas Signaling in vivo Using Synthetic Dimerizers" David Spencer, Pete Belshaw, Lei Chen, Steffan Ho, Filippo Randazzo, Gerald R. Crabtree, Stuart L. Schreiber Curr. Biol. 1996, 6, 839–848. Dimerizer kits have been distributed freely resulting in many peer-reviewed publications. Its promise in gene therapy has been highlighted by the ability of a small molecule to activate a small-molecule regulated EPO receptor and to induce erythropoiesis (Ariad Pharmaceuticals, Inc.), and more recently in human clinical trials for treatment of graft-vs-host disease.
In 1994, Schreiber and co-workers investigated (independently with David Sabitini) the master regulator of nutrient sensing, mTOR. They found that the small molecule Sirolimus simultaneously binds FKBP12 and mTOR (originally named FKBP12-rapamycin binding protein, FRAP). Using diversity-oriented synthesis and small-molecule screening, Schreiber illuminated the nutrient-response signaling network involving TOR proteins in yeast and mTOR in mammalian cells. Small molecules such as uretupamine"Dissection of a glucose-sensitive pathway of the nutrient-response network using diversity-oriented synthesis and small molecule microarrays" Finny G. Kuruvilla, Alykhan F. Shamji, Scott M. Sternson, Paul J. Hergenrother, Stuart L. Schreiber, Nature, 2002, 416, 653–656. and rapamycin were shown to be particularly effective in revealing the ability of proteins such as mTOR, Tor1p, Tor2p, and Ure2p to receive multiple inputs and to process them appropriately towards multiple outputs (in analogy to multi-channel processors). Several pharmaceutical companies are now targeting the nutrient-signaling network for the treatment of several forms of cancer, including solid tumors.
In 1995, Schreiber and co-workers found that the small molecule lactacystin binds and inhibits specific catalytic subunits of the proteasome, a protein complex responsible for the bulk of proteolysis in the cell, as well as proteolytic activation of certain protein substrates. As a non-peptidic proteasome inhibitor lactacysin has proven useful in the study of proteasome function. Lactacystin modifies the amino-terminal threonine of specific proteasome subunits. This work helped to establish the proteasome as a mechanistically novel class of protease: an amino-terminal threonine protease. The work led to the use of bortezomib to treat multiple myeloma.
In 1996, Schreiber and co-workers used the small molecules trapoxin and depudecin to investigate the histone deacetylases (HDACs). Prior to Schreiber's work in this area, the HDAC proteins had not been isolated. Coincident with the HDAC work, Charles David Allis and colleagues reported work on the histone acetyltransferases (HATs). These two contributions catalyzed much research in this area, eventually leading to the characterization of numerous histone-modifying enzymes, their resulting histone “marks”, and numerous proteins that bind to these marks. By taking a global approach to understanding chromatin function, Schreiber proposed a “signaling network model” of chromatin and compared it to an alternative view, the “histone code hypothesis” presented by Brian D. Strahl and Charles David Allis. These studies shined a bright light on chromatin as a key gene expression regulatory element rather than simply a structural element used for DNA compaction.
Using diversity-oriented synthesis, the Schreiber Lab and collaborators discovered numerous novel antimicrobial compounds including the bicyclic azetidine BRD7929 that could both cure and prevent the transmission of malaria in mice, targeting multiple steps in the life cycle of Plasmodium falciparum. They found another synthetic azetidine derivative, BRD4592, which kills Mycobacterium tuberculosis through allosteric inhibition of its tryptophan synthase. High throughput screens further uncovered compounds that inhibit replication of Trypanosoma cruzi and Hepatitis C virus, and inhibit Toxoplasma gondii growth.
Schrieber and McManus discovered that when certain aggressive cancer cells become resistant to drug treatments, they also become vulnerable to ferroptosis—a natural cellular self-destruction mechanism triggered by peroxide and iron ions undergoing the Fenton reaction. Free radicals unleash a chain reaction turning normal lipids in the cell membrane into toxic radical species. They found that drug-resistant cancer cells that have acquired this new vulnerability rely on an enzyme called GPX4 for survival. GPX4 stops the chain reaction leading to ferroptosis by converting the dangerous lipid peroxides to benign alcohols. They further showed that a small molecule inhibitor of GPX4 kills cancer cells by increasing their vulnerability to ferroptosis.
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