Jeffrey R Peterson

• PhD
• Professor (Full) at Fox Chase Cancer Center

Ferroptosis is a caspase-independent form of regulated cell death strongly linked to the accumulation of reactive lipid hydroperoxides. Lipid hydroperoxides are neutralized in cells by glutathione peroxidase 4 (GPX4) and inhibitors of GPX4 are potent ferroptosis inducers with therapeutic potential in cancer. Here we report that siRNA-mediated silen...

Inosine-5′-monophosphate dehydrogenase (IMPDH), a key regulatory enzyme in purine nucleotide biosynthesis, dynamically assembles filaments in response to changes in metabolic demand. Humans have two isoforms: IMPDH2 filaments reduce sensitivity to feedback inhibition, while IMPDH1 assembly remains uncharacterized. IMPDH1 plays a unique role in reti...

IMP dehydrogenase (IMPDH), a key regulatory enzyme in purine nucleotide biosynthesis, dynamically assembles filaments in response to changes in metabolic demand. Humans have two isoforms: IMPDH2 filaments reduce sensitivity to feedback inhibition by the downstream product GTP, while IMPDH1 assembly remains uncharacterized. IMPDH1 plays a unique rol...

Ferroptosis is associated with lipid hydroperoxides generated by the oxidation of polyunsaturated acyl chains. Lipid hydroperoxides are reduced by glutathione peroxidase 4 (GPX4) and GPX4 inhibitors induce ferroptosis. However, the therapeutic potential of triggering ferroptosis in cancer cells with polyunsaturated fatty acids is unknown. Here, we...

Polymerization of metabolic enzymes into micron-scale assemblies is an emerging mechanism for regulating their activity. CTP synthase (CTPS) is an essential enzyme in the biosynthesis of the nucleotide CTP and undergoes regulated and reversible assembly into large filamentous structures in organisms from bacteria to humans. The purpose of these ass...

Many different enzymes in intermediate metabolism dynamically assemble filamentous polymers in cells, often in response to changes in physiological conditions. Most of the enzyme filaments known to date have only been observed in cells, but in a handful of cases structural and biochemical studies have revealed the mechanisms and consequences of ass...

Purpose: For many tumors, signaling exchanges between cancer cells and other cells in their microenvironment influence overall tumor signaling. Some of these exchanges depend on expression of the primary cilium on nontransformed cell populations, as extracellular ligands including Sonic Hedgehog (SHH), PDGFRα, and others function through receptors...

Ferroptosis is a non-apoptotic form of cell death linked to the accumulation of reactive hydroperoxides generated by oxidation of polyunsaturated fatty acids (PUFAs) in membrane phospholipids. The therapeutic potential of promoting ferroptosis by enriching PUFAs in cancer cells is unknown. We found an association between elevated PUFA levels and vu...

T cell-mediated adaptive immunity requires naïve, unstimulated T cells to transition from a quiescent metabolic state into a highly proliferative state upon T cell receptor engagement. This complex process depends on transcriptional changes mediated by calcium-dependent NFAT signaling, mTOR-mediated signaling and increased activity of the guanine n...

T cell-mediated adaptive immunity requires naïve, unstimulated T cells to transition from a quiescent metabolic state into a highly proliferative state upon T cell receptor engagement. This complex process depends on transcriptional changes mediated by Ca2+-dependent NFAT signaling, mTOR-mediated signaling and increased activity of the guanine nucl...

Cancer cells can exhibit altered dependency on specific metabolic pathways and targeting these dependencies is a promising therapeutic strategy. Triple-negative breast cancer (TNBC) is an aggressive and genomically heterogeneous subset of breast cancer that is resistant to existing targeted therapies. To identify metabolic pathway dependencies in T...

Several metabolic enzymes undergo reversible polymerization into macromolecular assemblies. The function of these assemblies is often unclear but in some cases they regulate enzyme activity and metabolic homeostasis. The guanine nucleotide biosynthetic enzyme inosine monophosphate dehydrogenase (IMPDH) forms octamers that polymerize into helical ch...

Inosine monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme involved in purine nucleotide biosynthesis. It is responsible for catalyzing the oxidation of inosine monophosphate (IMP) into xanthosine monophosphate (XMP). Concurrently, the cofactor NAD+ is reduced to NADH. Poly(ADP-ribose) polymerase 1 (PARP-1) also utilizes NAD+ as a substr...

Several metabolic enzymes undergo reversible polymerization into macromolecular assemblies. The function of these assemblies is often unclear but in some cases they regulate enzyme activity and metabolic homeostasis. The guanine nucleotide biosynthetic enzyme inosine monophosphate dehydrogenase (IMPDH) forms octamers that polymerize into helical ch...

High-grade serous ovarian carcinoma (HGS-OvCa) is the most common and deadly form of ovarian cancer, and currently lacks effective targeted therapies. Recently, proteins involved in chromatin remodeling such as the BET bromodomain protein BRD4 have emerged as an exciting new class of targets for the treatment of cancer. Targeted BRD4 inhibition has...

The primary cilium is an antenna-like structure protruding from the cell surface, which provides a platform for receptors for signaling systems including PDGF-alpha, Hedgehog, Wnt, and others that influence cell differentiation and proliferation decisions. Under normal physiological growth conditions, the cilium forms after mitosis and in quiescent...

Small-molecule BET bromodomain inhibitors (BETis) are actively being pursued in clinical trials for the treatment of a variety of cancers, but the mechanisms of resistance to BETis remain poorly understood. Using a mass spectrometry approach that globally measures kinase signaling at the proteomic level, we evaluated the response of the kinome to t...

Small-molecule kinase inhibitors have typically been designed to inhibit wild-type kinases rather than the mutant forms that frequently arise in diseases such as cancer. Mutations can have serious clinical implications by increasing kinase catalytic activity or conferring therapeutic resistance. To identify opportunities to repurpose inhibitors aga...

Identifying metabolic pathway alterations that are critical to support cancer growth is a key hurdle for developing therapeutic strategies that exploit these pathways. We have applied metabolomic and pharmacological approaches to identify targetable pathways in triple negative breast cancer (TNBC). TNBC is an aggressive and genomically heterogeneou...

Protein kinase autophosphorylation is a common regulatory mechanism in cell signaling pathways. Crystal structures of several homomeric protein kinase complexes have a serine, threonine, or tyrosine autophosphorylation site of one kinase monomer located in the active site of another monomer, a structural complex that we call an "autophosphorylation...

Aberrant kinase signaling has been implicated in a number of diseases. While kinases have become attractive drug targets, only a small fraction of human protein kinases have validated inhibitors. Screening of libraries of compounds against a kinase or kinases of interest is routinely performed during kinase inhibitor development to identify promisi...

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA Small molecule kinase inhibitors are promising therapeutic agents in a number of diseases, most notably cancer. However, mutations in kinases, both intrinsic and acquired, can drastically alter inhibitor sensitivity. To identify inhibitors of disease-associated mutant...

Cancer therapy depends heavily on the ability to effectively control the activity of oncogenic kinases. Autophosphorylation is a common regulatory mechanism of kinases in signaling pathways, and commonly elevated in cancer. Several autophosphorylation complexes have been identified from within crystals of protein kinases, with a known autophosphory...

Structural coverage of the human kinome has been steadily increasing over time. The structures provide valuable insights into the molecular basis of kinase function and also provide a foundation for understanding the mechanisms of kinase inhibitors. There are a large number of kinase structures in the PDB for which the Asp and Phe of the DFG motif...

Triple-negative breast cancers (TNBC), negative for estrogen receptor, progesterone receptor, and ERBB2 amplification, are resistant to standard targeted therapies and exhibit a poor prognosis. Furthermore, they are highly heterogeneous with respect to genomic alterations, and common therapeutic targets are lacking though substantial evidence impli...

Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer that represents about 15-20% of all breast cancers. Because TNBC tumors do not express the estrogen or progesterone receptor and lack HER2 amplification, the disease is not responsive to current targeted therapies. The development of therapeutic approaches specific for TNBC...

The enzyme CTP synthase (CTPS) dynamically assembles into macromolecular filaments in bacteria, yeast, Drosophila, and mammalian cells, but the role of this morphological reorganization in regulating CTPS activity is controversial. During Drosophila oogenesis, CTPS filaments are transiently apparent in ovarian germline cells during a period of inte...

Inhibitors of the DNA damage checkpoint kinase, Chk1, are highly effective as chemo- and radio-sensitizers in preclinical studies but are not well-tolerated by patients. We exploited the promiscuous nature of kinase inhibitors to screen 9 clinically relevant kinase inhibitors for their ability to sensitize pancreatic cancer cells to a sub-lethal co...

Inhibitors of the DNA damage checkpoint kinase, Chk1, are highly effective as chemo- and radio-sensitizers in preclinical studies but are not well tolerated by patients. We took advantage of the promiscuous nature of kinase inhibitors and screened 9 clinically relevant kinase inhibitors for their ability to sensitize pancreatic cancer cells (Panc1)...

Eukaryotic protein kinases are generally classified as being either tyrosine or serine-threonine specific. Though not evident from inspection of their primary sequences, many serine-threonine kinases display a significant preference for serine or threonine as the phosphoacceptor residue. Here we show that a residue located in the kinase activation...

Dual inhibitors of the closely related receptor tyrosine kinases insulin-like growth factor 1 receptor (IGF-1R) and insulin receptor (IR) are promising therapeutic agents in cancer. Here we report an unusually selective class of dual inhibitors of IGF-1R and IR identified in a parallel screen of known kinase inhibitors against a panel of 300 human...

TNBC constitutes ∼20% of all breast cancers and disproportionately affects younger women and African-American women. This genomically heterogeneous disease is defined by the lack of expression of estrogen and progesterone receptors and the lack of amplification of HER2/neu. TNBC is resistant to standard breast cancer therapies. Due to the lack of a...

Triple-negative breast cancer (TNBC) constitutes approximately 20% of all breast cancer and disproportionately affects younger women and African-American women. These tumors, negative for estrogen receptor, progesterone receptor, and Her2 amplification, are resistant to standard targeted treatments, and the need for new therapeutic targets for this...

Dual inhibitors of the closely related receptor tyrosine kinases insulin-like growth factor 1 receptor (IGF-1R) and insulin receptor (IR) are promising therapeutic agents in cancer. Here, we report an unusually selective class of dual inhibitors of IGF-1R and IR identified in a parallel screen of known kinase inhibitors against a panel of 300 human...

Cellular senescence is a state of stable cell growth arrest. Activation of oncogenes such as RAS in mammalian cells typically triggers cellular senescence. Oncogene-induced senescence (OIS) is an important tumor suppression mechanism, and suppression of OIS contributes to cell transformation. Oncogenes trigger senescence through a multitude of inco...

Protein and lipid kinases play key regulatory roles in a number of biological processes. Unsurprisingly, activating mutations in kinases have been linked to a number of disorders and diseases, most notably cancers. Thus, kinases have emerged as promising clinical targets. There are more than 500 human protein kinases and about 20 lipid kinases. Mos...

Autoinhibited p21-activated kinase 1 (Pak1) can be activated in vitro by the plasma membrane-bound Rho GTPases Rac1 and Cdc42 as well as by the lipid phosphatidylinositol (4,5)-bisphosphate (PIP2). Activator binding is mediated by a GTPase-binding motif and an adjacent phosphoinositide-binding motif. Whether these two classes of activators play alt...

The serine/threonine protein kinases Mst1 and Mst2 can be activated by cellular stressors including hydrogen peroxide. Using two independent protein interaction screens, we show that these kinases associate, in an oxidation-dependent manner, with Prdx1, an enzyme that regulates the cellular redox state by reducing hydrogen peroxide to water and oxy...

Background: EBP1, an ErbB3-binding protein, sensitises breast cancer cells to tamoxifen in part by decreasing ErbB2 protein levels. The p21-regulated serine/threonine kinase PAK1, implicated in tamoxifen resistance, phosphorylates EBP1 in vitro and in vivo at T261. Phosphorylation of EBP1 at this site induces tamoxifen resistance. We thus postulate...

Protein kinases are among the most important drug targets; however the structural conservation of the ATP-binding pocket of kinases can lead to promiscuous inhibition of additional unintended kinase targets. Allosteric inhibitors that target less conserved regions of protein kinases represent an alternative approach that may provide more selective...

Group I p21–activated kinases (PAK) are important effectors of the small GTPases Rac and Cdc42, which regulate cell motility/migration, survival, proliferation, and gene transcription. Hyperactivation of these kinases have been reported in many tumor types, making PAKs attractive targets for therapeutic intervention. PAKs are activated by growth fa...

Kinase inhibitors are a growing class of therapeutically active agents that are being used in the clinic. An interesting notion is that inhibitors which show clinical efficacy likely do so by inhibiting not only their intended target but also off-target kinases. Thus, pleiotropic off-target effects of kinase inhibitors may be advantageous in preven...

Synaptic transmission is mediated by a complex set of molecular events that must be coordinated in time and space. While many proteins that function at the synapse have been identified, the signaling pathways regulating these molecules are poorly understood. Pak5 (p21-activated kinase 5) is a brain-specific isoform of the group II Pak kinases whose...

Biochemical and structural studies of p21-activated kinase 1 (Pak1) by Wang and colleagues in this issue of Structure reveal the structural basis for Pak1 trans-autophosphorylation of the activation loop, a critical step in the activation of kinases.

Small-molecule protein kinase inhibitors are widely used to elucidate cellular signaling pathways and are promising therapeutic agents. Owing to evolutionary conservation of the ATP-binding site, most kinase inhibitors that target this site promiscuously inhibit multiple kinases. Interpretation of experiments that use these compounds is confounded...

Supplementary Tables 1,2,4,5 and Supplementary Figures 1–5

Excel table of the complete pairwise kinase-compound activity dataset

Cell motility requires the spatial and temporal coordination of forces in the actomyosin cytoskeleton with extracellular adhesion. The biochemical mechanism that coordinates filamentous actin (F-actin) assembly, myosin contractility, adhesion dynamics, and motility to maintain the balance between adhesion and contraction remains unknown. In this pa...

Methylthioadenosine phosphorylase (MTAP), a key enzyme in the methionine salvage pathway, is inactivated in a variety of human cancers. Since all human tissues express MTAP, it would be of potential interest to identify compounds that selectively inhibit the growth of MTAP-deficient cells. To determine if MTAP inactivation could be targeted, the au...

Phospholipid-enriched membranes such as the plasma membrane can serve as direct regulators of kinase signaling. Pak1 is involved in growth factor signaling at the plasma membrane, and its dysregulation is implicated in cancer. Pak1 adopts an autoinhibited conformation that is relieved upon binding to membrane-bound Rho GTPases Rac1 or Cdc42, but wh...

Profens like ibuprofen, R-flurbiprofen, or CHF5074 are being considered for the treatment of Alzheimer's disease because epidemiological data indicates that non-steroidal anti-inflammatory drugs are protective against neurodegeneration. Rho-GTPases are small G proteins, including RhoA, Cdc42, and Rac1, which control cytoskeleton dynamics. Because i...

Kinases are important therapeutic targets in oncology due to their frequent deregulation in cancer. Typical ATP-competitive kinase inhibitors, however, also inhibit off-target kinases that could lead to drug toxicity. Allosteric inhibitors represent an alternative approach to achieve greater kinase selectivity, although examples of such compounds a...

Formins are potent actin assembly factors. Diaphanous formins, including mDia1, mDia2, and mDia3 in mammals, are implicated in mitosis and cytokinesis, but no chemical interactors have been reported. We developed an in vitro screen for inhibitors of actin assembly by mDia1 and identified an inhibitor of mDia1 and mDia2 that does not inhibit mDia3 a...

Merlin loss causes benign tumours of the nervous system, mainly schwannomas and meningiomas. Schwannomas show enhanced Rac1 and Cdc42 activity, the p21-activated kinase 2 (PAK2) activation and increased ruffling and cell adhesion. PAK regulates activation of merlin. PAK has been proposed as a potential therapeutic target in schwannomas. However whe...

CD4(+) T cells use the chemokine receptor CCR7 to home to and migrate within lymphoid tissue, where T-cell activation takes place. Using primary T-cell receptor (TCR)-transgenic (tg) CD4(+) T cells, we explored the effect of CCR7 ligands, in particular CCL21, on T-cell activation. We found that the presence of CCL21 during early time points strongl...

Shiga toxin 1 and 2 production is a cardinal virulence trait of enterohemorrhagic Escherichia coli infection that causes a spectrum of intestinal and systemic pathology. However, intestinal sites of enterohemorrhagic E. coli colonization during the human infection and how the Shiga toxins are taken up and cross the globotriaosylceramide (Gb3) recep...

Autoregulatory domains found within kinases may provide more unique targets for chemical inhibitors than the conserved ATP-binding pocket targeted by most inhibitors. The kinase Pak1 contains an autoinhibitory domain that suppresses the catalytic activity of its kinase domain. Pak1 activators relieve this autoinhibition and initiate conformational...

The Rho family of small GTP-binding proteins can activate a large number of downstream effectors and participate in a wide variety of biological processes, including cell motility, membrane trafficking, cell polarity, gene transcription, and mitosis. Specific small-molecule inhibitors of individual effector proteins downstream of Rho GTPases would...

The p21-activated kinases (Paks) serve as effectors of the Rho family GTPases Rac and Cdc42. The six human Paks are divided into two groups based on sequence similarity. Group I Paks (Pak1 to -3) phosphorylate a number of substrates linking this group to regulation of the cytoskeleton and both proliferative and anti-apoptotic signaling. Group II Pa...

p21-activated kinases have been classified into two groups based on their domain architecture. Group II PAKs (PAK4-6) regulate a wide variety of cellular functions, and PAK deregulation has been linked to tumor development. Structural comparison of five high-resolution structures comprising all active, monophosphorylated group II catalytic domains...

Cool-1 was previously identified as an effector of activated Cdc42 and as a regulator of epidermal growth factor receptor (EGFR) trafficking. Cool-1 has now been shown to be a phosphorylation-dependent activator of Cdc42 that contributes to transformation by Src, thus proving to be an unusually versatile signalling protein.

Identification of small-molecule targets remains an important challenge for chemical genetics. We report an approach for target identification and protein discovery based on functional suppression of chemical inhibition in vitro. We discovered pirl1, an inhibitor of actin assembly, in a screen conducted with cytoplasmic extracts. Pirl1 was used to...

Cyclic peptides offer the possibility of varying both scaffold geometry and R-group functionality. For example, parameters such as ring size and the placement of D-amino acid and proline residues can have a dramatic effect on the conformations of cyclic peptides, allowing access to structurally diverse species based on simple modifications in their...

Inspired by the usefulness of small molecules to study membrane traffic, we used high-throughput synthesis and phenotypic screening to discover secramine, a molecule that inhibits membrane traffic out of the Golgi apparatus by an unknown mechanism. We report here that secramine inhibits activation of the Rho GTPase Cdc42, a protein involved in memb...

Current drug discovery efforts generally focus on a limited number of protein classes, typically including proteins with well-defined catalytic active sites (e.g., kinases) or ligand binding sites (e.g., G protein-coupled receptors). Nevertheless, many clinically important pathways are mediated by proteins with no such obvious targets for small mol...

Current drug discovery efforts focus primarily on proteins with defined enzymatic or small molecule binding sites. Autoregulatory domains represent attractive alternative targets for small molecule inhibitors because they also occur in noncatalytic proteins and because allosteric inhibitors may avoid specificity problems inherent in active site-dir...

Chemical inhibitors, whether natural products or synthetic, have had an enormous impact on the study of the eukaryotic cytoskeleton. Here we review the history of some of the most widely used cytoskeletal poisons and their influence on our understanding of cytoskeletal functions. We then highlight several new inhibitors and the targeted screens use...

Chemical inhibitors, whether natural products or synthetic, have had an enormous impact on the study of the eukaryotic cytoskeleton. Here we review the history of some of the most widely used cytoskeletal poisons and their influence on our understanding of cytoskeletal functions. We then highlight several new inhibitors and the targeted screens use...

Cell morphology and motility are governed largely by complex signaling networks that ultimately engage the actin cytoskeleton. Understanding how individual circuits contribute to the process of forming cellular structures would be aided greatly by the availability of specific chemical inhibitors. We have used a novel chemical screen in Xenopus cell...

Calreticulin is a soluble, endoplasmic reticulum-resident protein and a molecular chaperone for glycoproteins. We have reconstituted the binding of recombinant calreticulin to two glycoprotein substrates, vesicular stomatitis virus G protein and influenza hemagglutinin, in vitro. The binding was found to be direct and to require monoglucosylated, a...

The soluble, calcium-binding protein calreticulin shares high sequence homology with calnexin, a transmembrane chaperone of glycoprotein folding. Our experiments demonstrated that calreticulin, like calnexin, associated transiently with numerous newly synthesized proteins in the endoplasmic reticulum. The population of proteins that bound to calret...

Although some of the ER chaperones, such as BiP/Kar2p and GRP94, are similar to those present in the cytosol and in mitochondria (and seem to function in a similar way), protein folding in the ER presents a rather different picture from that encountered elsewhere in the cell. First, no members of the chaperonin family seem to exist in the ER lumen...

The full-length cDNA encoding Rab23, a novel Ras-related small GTPase, was isolated using the sequence of a previously described [Chavrier et al., Gene 112 (1992) 261–264] short cDNA fragment and the rapid amplification of cDNA ends (RACE) PCR techniques. The deduced amino acid sequence was not very closely related to any previously described small...

This chapter examines the membrane glycolipid trafficking in living, polarized pancreatic acinar cells using confocal microscopy. When the confocal scanning laser microscope (CLSM) is equipped for video imaging through coupling to a digital host computer with image processing capabilities and a shuttering system, it becomes possible to image living...