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Sarah Williams

Bio: Sarah Williams is an academic researcher from Novartis. The author has contributed to research in topics: Allosteric regulation & Protein tyrosine phosphatase. The author has an hindex of 15, co-authored 31 publications receiving 1183 citations. Previous affiliations of Sarah Williams include Novartis Institute for Tropical Diseases.

Papers
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Journal ArticleDOI
07 Jul 2016-Nature
TL;DR: The discovery of a highly potent (IC50 = 0.071 μM), selective and orally bioavailable small-molecule SHP2 inhibitor, SHP099, that stabilizes SHp2 in an auto-inhibited conformation demonstrates that pharmacological inhibition of SHP1 is a valid therapeutic approach for the treatment of cancers.
Abstract: SHP099, a selective inhibitor of signalling meditator SHP2 with drug-like properties, has an allosteric mechanism of action whereby it stabilizes SHP2 in an auto-inhibited conformation, and suppresses RAS–ERK signalling and proliferation in receptor-tyrosine-kinase-driven cancer cell lines and mouse tumour xenograft models. The tyrosine phosphatase SHP2 is a key mediator of receptor tyrosine kinase (RTK) signalling, as well as being important in immune checkpoint pathways. Reduction of SHP2 activity suppresses tumour cell growth, and SHP2 is a potential, but so far elusive, therapeutic target in cancer. Pascal Fortin and colleagues report the development of a selective SHP2 inhibitor with drug-like properties. The inhibitor, SHP099, has an allosteric mechanism of action whereby it stabilizes SHP2 in an auto-inhibited conformation. It also suppresses RAS–ERK signalling to inhibit RTK-driven proliferation in human cancer cell lines and mouse tumour xenograft models. The non-receptor protein tyrosine phosphatase SHP2, encoded by PTPN11, has an important role in signal transduction downstream of growth factor receptor signalling and was the first reported oncogenic tyrosine phosphatase1. Activating mutations of SHP2 have been associated with developmental pathologies such as Noonan syndrome and are found in multiple cancer types, including leukaemia, lung and breast cancer and neuroblastoma1,2,3,4,5. SHP2 is ubiquitously expressed and regulates cell survival and proliferation primarily through activation of the RAS–ERK signalling pathway2,3. It is also a key mediator of the programmed cell death 1 (PD-1) and B- and T-lymphocyte attenuator (BTLA) immune checkpoint pathways6,7. Reduction of SHP2 activity suppresses tumour cell growth and is a potential target of cancer therapy8,9. Here we report the discovery of a highly potent (IC50 = 0.071 μM), selective and orally bioavailable small-molecule SHP2 inhibitor, SHP099, that stabilizes SHP2 in an auto-inhibited conformation. SHP099 concurrently binds to the interface of the N-terminal SH2, C-terminal SH2, and protein tyrosine phosphatase domains, thus inhibiting SHP2 activity through an allosteric mechanism. SHP099 suppresses RAS–ERK signalling to inhibit the proliferation of receptor-tyrosine-kinase-driven human cancer cells in vitro and is efficacious in mouse tumour xenograft models. Together, these data demonstrate that pharmacological inhibition of SHP2 is a valid therapeutic approach for the treatment of cancers.

624 citations

Journal ArticleDOI
TL;DR: The discovery of 6-(4-amino-4-methylpiperidin-1-yl)-3-(2,3-dichlorophenyl)pyrazin-2-amine (SHP099), a potent, selective, orally bioavailable, and efficacious SHP2 inhibitor.
Abstract: SHP2 is a nonreceptor protein tyrosine phosphatase (PTP) encoded by the PTPN11 gene involved in cell growth and differentiation via the MAPK signaling pathway. SHP2 also purportedly plays an important role in the programmed cell death pathway (PD-1/PD-L1). Because it is an oncoprotein associated with multiple cancer-related diseases, as well as a potential immunomodulator, controlling SHP2 activity is of significant therapeutic interest. Recently in our laboratories, a small molecule inhibitor of SHP2 was identified as an allosteric modulator that stabilizes the autoinhibited conformation of SHP2. A high throughput screen was performed to identify progressable chemical matter, and X-ray crystallography revealed the location of binding in a previously undisclosed allosteric binding pocket. Structure-based drug design was employed to optimize for SHP2 inhibition, and several new protein–ligand interactions were characterized. These studies culminated in the discovery of 6-(4-amino-4-methylpiperidin-1-yl)-3-...

214 citations

Journal Article
TL;DR: This study provides the first unbiased description ofRB-repressed genes, thereby delineating new aspects of RB-mediated transcriptional control and novel targets involved in diverse cellular processes.
Abstract: The retinoblastoma tumor suppressor, RB, is thought to inhibit cell cycle progression through transcriptional repression. E2F-regulated genes have been viewed as presumptive targets of RB-mediated repression. However, we found that specific E2F targets were not regulated in a consistent manner by the action of a RB allele that is refractory to cyclin-dependent kinase/cyclin-mediated phosphorylation (PSM-RB) when compared with E2F2 overproduction. Therefore, we used Affymetrix GeneChips as an unbiased approach to identify RB targets. We found that expression of PSM-RB significantly attenuates >200 targets, the majority of which are involved in cell cycle control (DNA replication or G2-M), DNA repair, or transcription/chromatin structure. The observed repression was due to the action of RB and not merely a manifestation of altered cell cycle distribution. Additionally, the majority of RB repression targets were confirmed through the blockade of endogenous RB phosphorylation via p16ink4a overexpression. Thus, these results have utility in assigning RB pathway activation in more complex systems of cell cycle inhibition (e.g., mitogen withdrawal, senescence, or DNA damage checkpoint). As expected, a significant fraction of RB-repressed genes have promoters that are bound/regulated by E2F family members. However, targets were identified that are distinct from genes known to be stimulated by overexpression of specific E2F proteins. Moreover, the relative action of RB versus E2F2 overexpression on specific genes demonstrates that a simple opposition model does not explain the relative contribution of RB to gene regulation. Thus, this study provides the first unbiased description of RB-repressed genes, thereby delineating new aspects of RB-mediated transcriptional control and novel targets involved in diverse cellular processes.

126 citations

Journal ArticleDOI
TL;DR: This work illustrates a rare example of dual allosteric targeted protein inhibition, demonstrates screening methodology and tactics to identifyAllosteric inhibitors, and enables further interrogation of SHP2 in cancer and related pathologies.
Abstract: SHP2 is a cytoplasmic protein tyrosine phosphatase encoded by the PTPN11 gene and is involved in cell proliferation, differentiation, and survival. Recently, we reported an allosteric mechanism of inhibition that stabilizes the auto-inhibited conformation of SHP2. SHP099 (1) was identified and characterized as a moderately potent, orally bioavailable, allosteric small molecule inhibitor, which binds to a tunnel-like pocket formed by the confluence of three domains of SHP2. In this report, we describe further screening strategies that enabled the identification of a second, distinct small molecule allosteric site. SHP244 (2) was identified as a weak inhibitor of SHP2 with modest thermal stabilization of the enzyme. X-ray crystallography revealed that 2 binds and stabilizes the inactive, closed conformation of SHP2, at a distinct, previously unexplored binding site-a cleft formed at the interface of the N-terminal SH2 and PTP domains. Derivatization of 2 using structure-based design resulted in an increase in SHP2 thermal stabilization, biochemical inhibition, and subsequent MAPK pathway modulation. Downregulation of DUSP6 mRNA, a downstream MAPK pathway marker, was observed in KYSE-520 cancer cells. Remarkably, simultaneous occupation of both allosteric sites by 1 and 2 was possible, as characterized by cooperative biochemical inhibition experiments and X-ray crystallography. Combining an allosteric site 1 inhibitor with an allosteric site 2 inhibitor led to enhanced pharmacological pathway inhibition in cells. This work illustrates a rare example of dual allosteric targeted protein inhibition, demonstrates screening methodology and tactics to identify allosteric inhibitors, and enables further interrogation of SHP2 in cancer and related pathologies.

103 citations

Journal ArticleDOI
TL;DR: In this article, the pyrazine class of allosteric SHP2 inhibitors were identified and optimized in parallel to identify protein-ligand interactions, potent cellular inhibition, control of physicochemical, pharmaceutical and selectivity properties, and potent in vivo antitumor activity.
Abstract: SHP2 is a nonreceptor protein tyrosine phosphatase encoded by the PTPN11 gene and is involved in cell growth and differentiation via the MAPK signaling pathway. SHP2 also plays an important role in the programed cell death pathway (PD-1/PD-L1). As an oncoprotein as well as a potential immunomodulator, controlling SHP2 activity is of high therapeutic interest. As part of our comprehensive program targeting SHP2, we identified multiple allosteric binding modes of inhibition and optimized numerous chemical scaffolds in parallel. In this drug annotation report, we detail the identification and optimization of the pyrazine class of allosteric SHP2 inhibitors. Structure and property based drug design enabled the identification of protein-ligand interactions, potent cellular inhibition, control of physicochemical, pharmaceutical and selectivity properties, and potent in vivo antitumor activity. These studies culminated in the discovery of TNO155, (3S,4S)-8-(6-amino-5-((2-amino-3-chloropyridin-4-yl)thio)pyrazin-2-yl)-3-methyl-2-oxa-8-azaspiro[4.5]decan-4-amine (1), a highly potent, selective, orally efficacious, and first-in-class SHP2 inhibitor currently in clinical trials for cancer.

82 citations


Cited by
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Journal ArticleDOI
TL;DR: Recent advances in understanding of the mechanisms by which bacteria are either intrinsically resistant or acquire resistance to antibiotics are reviewed, including the prevention of access to drug targets, changes in the structure and protection of antibiotic targets and the direct modification or inactivation of antibiotics.
Abstract: Antibiotic-resistant bacteria that are difficult or impossible to treat are becoming increasingly common and are causing a global health crisis. Antibiotic resistance is encoded by several genes, many of which can transfer between bacteria. New resistance mechanisms are constantly being described, and new genes and vectors of transmission are identified on a regular basis. This article reviews recent advances in our understanding of the mechanisms by which bacteria are either intrinsically resistant or acquire resistance to antibiotics, including the prevention of access to drug targets, changes in the structure and protection of antibiotic targets and the direct modification or inactivation of antibiotics.

2,837 citations

Journal ArticleDOI
08 May 2019-Nature
TL;DR: The original Cancer Cell Line Encyclopedia is expanded with deeper characterization of over 1,000 cell lines, including genomic, transcriptomic, and proteomic data, and integration with drug-sensitivity and gene-dependency data, which reveals potential targets for cancer drugs and associated biomarkers.
Abstract: Large panels of comprehensively characterized human cancer models, including the Cancer Cell Line Encyclopedia (CCLE), have provided a rigorous framework with which to study genetic variants, candidate targets, and small-molecule and biological therapeutics and to identify new marker-driven cancer dependencies. To improve our understanding of the molecular features that contribute to cancer phenotypes, including drug responses, here we have expanded the characterizations of cancer cell lines to include genetic, RNA splicing, DNA methylation, histone H3 modification, microRNA expression and reverse-phase protein array data for 1,072 cell lines from individuals of various lineages and ethnicities. Integration of these data with functional characterizations such as drug-sensitivity, short hairpin RNA knockdown and CRISPR-Cas9 knockout data reveals potential targets for cancer drugs and associated biomarkers. Together, this dataset and an accompanying public data portal provide a resource for the acceleration of cancer research using model cancer cell lines.

1,801 citations

Journal ArticleDOI
TL;DR: How CDK inhibitors with high selectivity (particularly for both CDK4 and CDK6), in combination with patient stratification, have resulted in more substantial clinical activity is discussed.
Abstract: Cancer represents a pathological manifestation of uncontrolled cell division; therefore, it has long been anticipated that our understanding of the basic principles of cell cycle control would result in effective cancer therapies. In particular, cyclin-dependent kinases (CDKs) that promote transition through the cell cycle were expected to be key therapeutic targets because many tumorigenic events ultimately drive proliferation by impinging on CDK4 or CDK6 complexes in the G1 phase of the cell cycle. Moreover, perturbations in chromosomal stability and aspects of S phase and G2/M control mediated by CDK2 and CDK1 are pivotal tumorigenic events. Translating this knowledge into successful clinical development of CDK inhibitors has historically been challenging, and numerous CDK inhibitors have demonstrated disappointing results in clinical trials. Here, we review the biology of CDKs, the rationale for therapeutically targeting discrete kinase complexes and historical clinical results of CDK inhibitors. We also discuss how CDK inhibitors with high selectivity (particularly for both CDK4 and CDK6), in combination with patient stratification, have resulted in more substantial clinical activity.

1,276 citations

Journal Article
TL;DR: Results indicate that inhibition of Cdk4/6 alone is sufficient to cause tumor regression and a net reduction in tumor burden in some tumors.
Abstract: PD 0332991 is a highly specific inhibitor of cyclin-dependent kinase 4 (Cdk4) (IC50, 0.011 micromol/L) and Cdk6 (IC50, 0.016 micromol/L), having no activity against a panel of 36 additional protein kinases. It is a potent antiproliferative agent against retinoblastoma (Rb)-positive tumor cells in vitro, inducing an exclusive G1 arrest, with a concomitant reduction of phospho-Ser780/Ser795 on the Rb protein. Oral administration of PD 0332991 to mice bearing the Colo-205 human colon carcinoma produces marked tumor regression. Therapeutic doses of PD 0332991 cause elimination of phospho-Rb and the proliferative marker Ki-67 in tumor tissue and down-regulation of genes under the transcriptional control of E2F. The results indicate that inhibition of Cdk4/6 alone is sufficient to cause tumor regression and a net reduction in tumor burden in some tumors.

1,150 citations

Journal ArticleDOI
Xue-Ru Wu1
TL;DR: This work has shown that correcting pathway-specific defects represents an attractive strategy for the molecular therapy of urothelial carcinomas.
Abstract: Urothelial carcinoma of the bladder is unique among epithelial carcinomas in its divergent pathways of tumorigenesis. Low-grade papillary tumours rarely become muscle-invasive and they frequently harbour gene mutations that constitutively activate the receptor tyrosine kinase-Ras pathway. By contrast, most high-grade invasive tumours progress to life-threatening metastases and have defects in the p53 and the retinoblastoma protein pathways. Correcting pathway-specific defects represents an attractive strategy for the molecular therapy of urothelial carcinomas.

651 citations