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1.
Nat Cancer ; 2024 May 30.
Article En | MEDLINE | ID: mdl-38816660

Dose-limiting toxicity poses a major limitation to the clinical utility of targeted cancer therapies, often arising from target engagement in nonmalignant tissues. This obstacle can be minimized by targeting cancer dependencies driven by proteins with tissue-restricted and/or tumor-restricted expression. In line with another recent report, we show here that, in acute myeloid leukemia (AML), suppression of the myeloid-restricted PIK3CG/p110γ-PIK3R5/p101 axis inhibits protein kinase B/Akt signaling and compromises AML cell fitness. Furthermore, silencing the genes encoding PIK3CG/p110γ or PIK3R5/p101 sensitizes AML cells to established AML therapies. Importantly, we find that existing small-molecule inhibitors against PIK3CG are insufficient to achieve a sustained long-term antileukemic effect. To address this concern, we developed a proteolysis-targeting chimera (PROTAC) heterobifunctional molecule that specifically degrades PIK3CG and potently suppresses AML progression alone and in combination with venetoclax in human AML cell lines, primary samples from patients with AML and syngeneic mouse models.

2.
bioRxiv ; 2024 May 16.
Article En | MEDLINE | ID: mdl-38798624

The Leishmania life cycle alternates between promastigotes, found in the sandfly, and amastigotes, found in mammals. When an infected sandfly bites a host, promastigotes are engulfed by phagocytes (i.e., neutrophils, dendritic cells, and macrophages) to establish infection. When these phagocytes die or break down, amastigotes must be re-internalized to survive within the acidic phagolysosome and establish disease. To define host kinase regulators of Leishmania promastigote and amastigote uptake and survival within macrophages, we performed an image-based kinase regression screen using a panel of 38 kinase inhibitors with unique and overlapping kinase targets. We also targeted inert beads to complement receptor 3 (CR3) or Fcγ receptors (FcR) as controls by coating them with complement/C3bi or IgG respectively. Through this approach, we identified several host kinases that regulate receptor-mediated phagocytosis and/or the uptake of L. amazonensis. Findings included kinases previously implicated in Leishmania uptake (such as SRC family kinases (SFK), Abl family kinases (ABL1/c-Abl, ABL2/Arg), and spleen tyrosine kinase (SYK)); we also uncovered many novel kinases. These methods also predicted kinases necessary for promastigotes to convert to amastigotes or for amastigotes to survive within macrophages. Overall, our results suggest that the concerted action of multiple interconnected networks of host kinases are needed over the course of Leishmania infection, and that the kinases required for the parasite's life cycle substantially differ depending on which receptors are bound and the life cycle stage that is internalized. In addition, using our screen, we identified kinases that preferentially regulate the uptake of parasites over beads, indicating that the methods required for Leishmania to be internalized by macrophages differ significantly from generalized phagocytic mechanisms. Our findings are intended to be used as a hypothesis generation resource for the broader scientific community studying the roles of kinases in host-pathogen interactions.

3.
Cell Rep Med ; 4(11): 101244, 2023 11 21.
Article En | MEDLINE | ID: mdl-37858338

Uveal melanoma (UM) is the most prevalent cancer of the eye in adults, driven by activating mutation of GNAQ/GNA11; however, there are limited therapies against UM and metastatic UM (mUM). Here, we perform a high-throughput chemogenetic drug screen in GNAQ-mutant UM contrasted with BRAF-mutant cutaneous melanoma, defining the druggable landscape of these distinct melanoma subtypes. Across all compounds, darovasertib demonstrates the highest preferential activity against UM. Our investigation reveals that darovasertib potently inhibits PKC as well as PKN/PRK, an AGC kinase family that is part of the "dark kinome." We find that downstream of the Gαq-RhoA signaling axis, PKN converges with ROCK to control FAK, a mediator of non-canonical Gαq-driven signaling. Strikingly, darovasertib synergizes with FAK inhibitors to halt UM growth and promote cytotoxic cell death in vitro and in preclinical metastatic mouse models, thus exposing a signaling vulnerability that can be exploited as a multimodal precision therapy against mUM.


Melanoma , Skin Neoplasms , Uveal Neoplasms , Animals , Mice , Melanoma/drug therapy , Melanoma/genetics , Melanoma/pathology , GTP-Binding Protein alpha Subunits/genetics , GTP-Binding Protein alpha Subunits/metabolism , GTP-Binding Protein alpha Subunits, Gq-G11/genetics , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , GTP-Binding Protein alpha Subunits, Gq-G11/therapeutic use , Drug Evaluation, Preclinical , Uveal Neoplasms/drug therapy , Uveal Neoplasms/genetics , Uveal Neoplasms/metabolism , Protein Kinase Inhibitors/pharmacology
4.
Sci Signal ; 16(772): eabq7842, 2023 02 14.
Article En | MEDLINE | ID: mdl-36787384

Heterotrimeric guanine nucleotide-binding proteins (G proteins) that function as molecular switches for cellular growth and metabolism are activated by GTP and inactivated by GTP hydrolysis. In uveal melanoma, a conserved glutamine residue critical for GTP hydrolysis in the G protein α subunit is often mutated in Gαq or Gα11 to either leucine or proline. In contrast, other glutamine mutations or mutations in other Gα subtypes are rare. To uncover the mechanism of the genetic selection and the functional role of this glutamine residue, we analyzed all possible substitutions of this residue in multiple Gα isoforms. Through cell-based measurements of activity, we showed that some mutants were further activated and inactivated by G protein-coupled receptors. Through biochemical, molecular dynamics, and nuclear magnetic resonance-based structural studies, we showed that the Gα mutants were functionally distinct and conformationally diverse, despite their shared inability to hydrolyze GTP. Thus, the catalytic glutamine residue contributes to functions beyond GTP hydrolysis, and these functions include subtype-specific, allosteric modulation of receptor-mediated subunit dissociation. We conclude that G proteins do not function as simple on-off switches. Rather, signaling emerges from an ensemble of active states, a subset of which are favored in disease and may be uniquely responsive to receptor-directed ligands.


Glutamine , Heterotrimeric GTP-Binding Proteins , Catalytic Domain , Glutamine/genetics , Heterotrimeric GTP-Binding Proteins/metabolism , Mutation , Guanosine Triphosphate/chemistry
5.
J Biol Chem ; 299(2): 102866, 2023 02.
Article En | MEDLINE | ID: mdl-36596361

G proteins and G protein-coupled receptors activate a diverse array of signal transduction pathways that promote cell growth and survival. Indeed, hot spot-activating mutations in GNAQ/GNA11, encoding Gαq proteins, are known to be driver oncogenes in uveal melanoma (UM), for which there are limited effective therapies currently available. Focal adhesion kinase (FAK) has been recently shown to be a central mediator of Gαq-driven signaling in UM, and as a result, is being explored clinically as a therapeutic target for UM, both alone and in combination therapies. Despite this, the repertoire of Gαq/FAK-regulated signaling mechanisms have not been fully elucidated. Here, we used a whole-genome CRISPR screen in GNAQ-mutant UM cells to identify mechanisms that, when overactivated, lead to reduced sensitivity to FAK inhibition. In this way, we found that the PI3K/AKT signaling pathway represented a major resistance driver. Our dissection of the underlying mechanisms revealed that Gαq promotes PI3K/AKT activation via a conserved signaling circuitry mediated by FAK. Further analysis demonstrated that FAK activates PI3K through the association and tyrosine phosphorylation of the p85 regulatory subunit of PI3K and that UM cells require PI3K/AKT signaling for survival. These findings establish a novel link between Gαq-driven signaling and the stimulation of PI3K as well as demonstrate aberrant activation of signaling networks underlying the growth and survival of UM and other Gαq-driven malignancies.


Carcinogenesis , Focal Adhesion Protein-Tyrosine Kinases , GTP-Binding Protein alpha Subunits, Gq-G11 , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-akt , Clustered Regularly Interspaced Short Palindromic Repeats , Focal Adhesion Protein-Tyrosine Kinases/genetics , Focal Adhesion Protein-Tyrosine Kinases/metabolism , GTP-Binding Protein alpha Subunits/metabolism , GTP-Binding Protein alpha Subunits, Gq-G11/genetics , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , Humans , Carcinogenesis/genetics
6.
J Exp Clin Cancer Res ; 41(1): 193, 2022 Jun 03.
Article En | MEDLINE | ID: mdl-35655319

BACKGROUND: Understanding the intricate signaling network involved in triple-negative breast cancer (TNBC) represents a challenge for developing novel therapeutic approaches. Here, we aim to provide novel mechanistic insights on the function of the S100A8/A9-RAGE system in TNBC. METHODS: TNM plot analyzer, Kaplan-Meier plotter, Meta-analysis, GEPIA2 and GOBO publicly available datasets were used to evaluate the clinical significance of S100A8/A9 and expression levels of S100A8/A9, RAGE and Filamin family members in breast cancer (BC) subtypes. METABRIC database and Cox proportional hazard model defined the clinical impact of high RAGE expression in BC patients. Multiple bioinformatics programs identified the main enriched pathways within high RAGE expression BC cohorts. By lentiviral system, TNBC cells were engineered to overexpress RAGE. Western blotting, immunofluorescence, nucleus/cytoplasm fractionation, qRT-PCR, gene silencing and luciferase experiments were performed to identify signal transduction mediators engaged by RAGE upon stimulation with S100A8/A9 in TNBC cells. Proliferation, colony formation and transwell migration assays were carried out to evaluate the growth and migratory capacity of TNBC cells. Statistical analysis was performed by ANOVA and independent t-tests. RESULTS: We found a remarkable high expression of S100A8 and S100A9 in BC, particularly in HER2-positive and TNBC, with the latter associated to worst clinical outcomes. In addition, high RAGE expression correlated with a poor overall survival in BC. Next, we determined that the S100A8/A9-RAGE system triggers FAK activation by engaging a cytoskeleton mechanosensing complex in TNBC cells. Through bioinformatics analysis, we identified the Hippo pathway as the most enriched in BC patients expressing high RAGE levels. In accordance with these data, we demonstrated the involvement of S100A8/A9-RAGE-FAK signaling in the control of Hippo/YAP activities, and we established the crucial contribution of RAGE-FAK-YAP circuitry in the growth and migratory effects initiated by S100A8/A9 in TNBC cells. CONCLUSIONS: The present study provides novel mechanistic insights on RAGE actions in TNBC. Moreover, our findings suggest that RAGE-FAK-YAP transduction pathway could be exploited as a druggable system halting the aggressive TNBC subtype.


Triple Negative Breast Neoplasms , Cell Adhesion , Focal Adhesion Protein-Tyrosine Kinases , Hippo Signaling Pathway , Humans , Signal Transduction , Triple Negative Breast Neoplasms/genetics
7.
Cell Chem Biol ; 29(9): 1419-1433.e5, 2022 09 15.
Article En | MEDLINE | ID: mdl-35738280

Prior to initiating symptomatic malaria, a single Plasmodium sporozoite infects a hepatocyte and develops into thousands of merozoites, in part by scavenging host resources, likely delivered by vesicles. Here, we demonstrate that host microtubules (MTs) dynamically reorganize around the developing liver stage (LS) parasite to facilitate vesicular transport to the parasite. Using a genome-wide CRISPR-Cas9 screen, we identified host regulators of cytoskeleton organization, vesicle trafficking, and ER/Golgi stress that regulate LS development. Foci of γ-tubulin localized to the parasite periphery; depletion of centromere protein J (CENPJ), a novel regulator identified in the screen, exacerbated this re-localization and increased infection. We demonstrate that the Golgi acts as a non-centrosomal MT organizing center (ncMTOC) by positioning γ-tubulin and stimulating MT nucleation at parasite periphery. Together, these data support a model where the Plasmodium LS recruits host Golgi to form MT-mediated conduits along which host organelles are recruited to PVM and support parasite development.


Malaria , Microtubule-Associated Proteins , Microtubules , CRISPR-Cas Systems , Humans , Liver/metabolism , Liver/parasitology , Malaria/metabolism , Microtubule-Associated Proteins/metabolism , Microtubules/metabolism , Plasmodium/metabolism , Tubulin/metabolism
8.
ACS Biomater Sci Eng ; 8(1): 196-207, 2022 01 10.
Article En | MEDLINE | ID: mdl-34927415

The use of cyclosporine A (CsA) in transplantation is frequently associated with nephrotoxicity, characterized by renal vascular injury, thrombotic microangiopathy, and striped interstitial fibrosis. Here, using human kidney-specific microvascular endothelial cells (HKMECs), we showed that CsA inhibited NFAT1 activation and impaired VEGF signaling in these ECs in a dose- and time-dependent manner. Integrated genome regulatory analyses identified key distinctions in the landscapes of HKMECs compared to human umbilical vein endothelial cells, particularly around genes related to the formation and maintenance of fenestrae. Using a bioengineered flow-directed 3D kidney microphysiological system, we revealed that CsA-induced kidney microvascular injury was associated with fenestrae and cell adhesion impairment, membrane swelling, and erythrocyte adhesion and extravasation into the interstitial space. Our data provide novel insights into kidney-specific molecular and structural mechanisms of CsA-induced microvascular injury. Our results also suggest VEGF-related pathways as potential targets for therapy during CsA treatment and emphasize the importance of leveraging species and organ-specific cells to better reflect human pathophysiology and the response to injury.


Cyclosporine , Endothelial Cells , Cyclosporine/toxicity , Humans , Immunosuppressive Agents/toxicity , Kidney , Microvessels
9.
Commun Biol ; 4(1): 1237, 2021 11 01.
Article En | MEDLINE | ID: mdl-34725466

The Hippo pathway is frequently dysregulated in cancer, leading to the unrestrained activity of its downstream targets, YAP/TAZ, and aberrant tumor growth. However, the precise mechanisms leading to YAP/TAZ activation in most cancers is still poorly understood. Analysis of large tissue collections revealed YAP activation in most head and neck squamous cell carcinoma (HNSCC), but only 29.8% of HNSCC cases present genetic alterations in the FAT1 tumor suppressor gene that may underlie persistent YAP signaling. EGFR is overexpressed in HNSCC and many other cancers, but whether EGFR controls YAP activation is still poorly understood. Here, we discover that EGFR activates YAP/TAZ in HNSCC cells, but independently of its typical signaling targets, including PI3K. Mechanistically, we find that EGFR promotes the phosphorylation of MOB1, a core Hippo pathway component, and the inactivation of LATS1/2 independently of MST1/2. Transcriptomic analysis reveals that erlotinib, a clinical EGFR inhibitor, inactivates YAP/TAZ. Remarkably, loss of LATS1/2, resulting in aberrant YAP/TAZ activity, confers erlotinib resistance on HNSCC and lung cancer cells. Our findings suggest that EGFR-YAP/TAZ signaling plays a growth-promoting role in cancers harboring EGFR alterations, and that inhibition of YAP/TAZ in combination with EGFR might be beneficial to prevent treatment resistance and cancer recurrence.


Adaptor Proteins, Signal Transducing/metabolism , ErbB Receptors/genetics , Hippo Signaling Pathway , Intracellular Signaling Peptides and Proteins/metabolism , Tyrosine/metabolism , Animals , ErbB Receptors/metabolism , Female , Gene Expression Regulation , Genes, erbB-1/genetics , Mice , Phosphorylation
10.
Pharmacol Rev ; 73(4): 155-197, 2021 10.
Article En | MEDLINE | ID: mdl-34663687

Many of the fundamental concepts of signal transduction and kinase activity are attributed to the discovery and crystallization of cAMP-dependent protein kinase, or protein kinase A. PKA is one of the best-studied kinases in human biology, with emphasis in biochemistry and biophysics, all the way to metabolism, hormone action, and gene expression regulation. It is surprising, however, that our understanding of PKA's role in disease is largely underappreciated. Although genetic mutations in the PKA holoenzyme are known to cause diseases such as Carney complex, Cushing syndrome, and acrodysostosis, the story largely stops there. With the recent explosion of genomic medicine, we can finally appreciate the broader role of the Gαs-PKA pathway in disease, with contributions from aberrant functioning G proteins and G protein-coupled receptors, as well as multiple alterations in other pathway components and negative regulators. Together, these represent a broad family of diseases we term the Gαs-PKA pathway signalopathies. The Gαs-PKA pathway signalopathies encompass diseases caused by germline, postzygotic, and somatic mutations in the Gαs-PKA pathway, with largely endocrine and neoplastic phenotypes. Here, we present a signaling-centric review of Gαs-PKA-driven pathophysiology and integrate computational and structural analysis to identify mutational themes commonly exploited by the Gαs-PKA pathway signalopathies. Major mutational themes include hotspot activating mutations in Gαs, encoded by GNAS, and mutations that destabilize the PKA holoenzyme. With this review, we hope to incite further study and ultimately the development of new therapeutic strategies in the treatment of a wide range of human diseases. SIGNIFICANCE STATEMENT: Little recognition is given to the causative role of Gαs-PKA pathway dysregulation in disease, with effects ranging from infectious disease, endocrine syndromes, and many cancers, yet these disparate diseases can all be understood by common genetic themes and biochemical signaling connections. By highlighting these common pathogenic mechanisms and bridging multiple disciplines, important progress can be made toward therapeutic advances in treating Gαs-PKA pathway-driven disease.


Cyclic AMP-Dependent Protein Kinases , Genomic Medicine , Cyclic AMP-Dependent Protein Kinases/metabolism , GTP-Binding Protein alpha Subunits, Gs/genetics , GTP-Binding Protein alpha Subunits, Gs/metabolism , Humans , Mutation , Signal Transduction
12.
Clin Cancer Res ; 27(11): 3190-3200, 2021 06 01.
Article En | MEDLINE | ID: mdl-33568347

PURPOSE: Uveal melanoma is the most common eye cancer in adults. Approximately 50% of patients with uveal melanoma develop metastatic uveal melanoma (mUM) in the liver, even after successful treatment of the primary lesions. mUM is refractory to current chemo- and immune-therapies, and most mUM patients die within a year. Uveal melanoma is characterized by gain-of-function mutations in GNAQ/GNA11, encoding Gαq proteins. We have recently shown that the Gαq-oncogenic signaling circuitry involves a noncanonical pathway distinct from the classical activation of PLCß and MEK-ERK. GNAQ promotes the activation of YAP1, a key oncogenic driver, through focal adhesion kinase (FAK), thereby identifying FAK as a druggable signaling hub downstream from GNAQ. However, targeted therapies often activate compensatory resistance mechanisms leading to cancer relapse and treatment failure. EXPERIMENTAL DESIGN: We performed a kinome-wide CRISPR-Cas9 sgRNA screen to identify synthetic lethal gene interactions that can be exploited therapeutically. Candidate adaptive resistance mechanisms were investigated by cotargeting strategies in uveal melanoma and mUM in vitro and in vivo experimental systems. RESULTS: sgRNAs targeting the PKC and MEK-ERK signaling pathways were significantly depleted after FAK inhibition, with ERK activation representing a predominant resistance mechanism. Pharmacologic inhibition of MEK and FAK showed remarkable synergistic growth-inhibitory effects in uveal melanoma cells and exerted cytotoxic effects, leading to tumor collapse in uveal melanoma xenograft and liver mUM models in vivo. CONCLUSIONS: Coupling the unique genetic landscape of uveal melanoma with the power of unbiased genetic screens, our studies reveal that FAK and MEK-ERK cotargeting may provide a new network-based precision therapeutic strategy for mUM treatment.See related commentary by Harbour, p. 2967.


Focal Adhesion Kinase 1/metabolism , GTP-Binding Protein alpha Subunits, Gq-G11/genetics , Gain of Function Mutation , Genetic Testing/methods , MAP Kinase Signaling System/genetics , Melanoma/genetics , Melanoma/therapy , Molecular Targeted Therapy , Uveal Neoplasms/genetics , Uveal Neoplasms/therapy , Animals , Combined Modality Therapy , Female , HEK293 Cells , Humans , MAP Kinase Signaling System/physiology , Mice, Inbred NOD , Mice, SCID , Xenograft Model Antitumor Assays
13.
FEBS Lett ; 594(24): 4201-4232, 2020 12.
Article En | MEDLINE | ID: mdl-33270228

G protein-coupled receptors (GPCRs) and heterotrimeric G proteins play central roles in a diverse array of cellular processes. As such, dysregulation of GPCRs and their coupled heterotrimeric G proteins can dramatically alter the signalling landscape and functional state of a cell. Consistent with their fundamental physiological functions, GPCRs and their effector heterotrimeric G proteins are implicated in some of the most prevalent human diseases, including a complex disease such as cancer that causes significant morbidity and mortality worldwide. GPCR/G protein-mediated signalling impacts oncogenesis at multiple levels by regulating tumour angiogenesis, immune evasion, metastasis, and drug resistance. Here, we summarize the growing body of research on GPCRs and their effector heterotrimeric G proteins as drivers of cancer initiation and progression, and as emerging antitumoural therapeutic targets.


Carcinogenesis , Disease Progression , Heterotrimeric GTP-Binding Proteins/metabolism , Neoplasms/metabolism , Neoplasms/pathology , Receptors, G-Protein-Coupled/metabolism , Signal Transduction , Humans
14.
Oncogene ; 39(20): 4014-4027, 2020 05.
Article En | MEDLINE | ID: mdl-32205868

Prostate cancer (PCa) innervation contributes to the progression of PCa. However, the precise impact of innervation on PCa cells is still poorly understood. By focusing on muscarinic receptors, which are activated by the nerve-derived neurotransmitter acetylcholine, we show that muscarinic receptors 1 and 3 (m1 and m3) are highly expressed in PCa clinical specimens compared with all other cancer types, and that amplification or gain of their corresponding encoding genes (CHRM1 and CHRM3, respectively) represent a worse prognostic factor for PCa progression free survival. Moreover, m1 and m3 gene gain or amplification is frequent in castration-resistant PCa (CRPC) compared with hormone-sensitive PCa (HSPC) specimens. This was reflected in HSPC-derived cells, which show aberrantly high expression of m1 and m3 under androgen deprivation mimicking castration and androgen receptor inhibition. We also show that pharmacological activation of m1 and m3 signaling is sufficient to induce the castration-resistant growth of PCa cells. Mechanistically, we found that m1 and m3 stimulation induces YAP activation through FAK, whose encoding gene, PTK2 is frequently amplified in CRPC cases. Pharmacological inhibition of FAK and knockdown of YAP abolished m1 and m3-induced castration-resistant growth of PCa cells. Our findings provide novel therapeutic opportunities for muscarinic-signal-driven CRPC progression by targeting the FAK-YAP signaling axis.


Adaptor Proteins, Signal Transducing/metabolism , Focal Adhesion Kinase 1/metabolism , Neoplasm Proteins/metabolism , Prostatic Neoplasms, Castration-Resistant/metabolism , Receptor, Muscarinic M1/biosynthesis , Receptor, Muscarinic M3/biosynthesis , Signal Transduction , Transcription Factors/metabolism , Adaptor Proteins, Signal Transducing/genetics , Focal Adhesion Kinase 1/genetics , Humans , Male , Neoplasm Proteins/genetics , PC-3 Cells , Prostatic Neoplasms, Castration-Resistant/genetics , Prostatic Neoplasms, Castration-Resistant/pathology , Receptor, Muscarinic M1/genetics , Receptor, Muscarinic M3/genetics , Transcription Factors/genetics , YAP-Signaling Proteins
15.
Cell Death Differ ; 27(1): 44-54, 2020 01.
Article En | MEDLINE | ID: mdl-31065106

The facets of host control during Plasmodium liver infection remain largely unknown. We find that the SLC7a11-GPX4 pathway, which has been associated with the production of reactive oxygen species, lipid peroxidation, and a form of cell death called ferroptosis, plays a critical role in control of Plasmodium liver stage infection. Specifically, blocking GPX4 or SLC7a11 dramatically reduces Plasmodium liver stage parasite infection. In contrast, blocking negative regulators of this pathway, NOX1 and TFR1, leads to an increase in liver stage infection. We have shown previously that increased levels of P53 reduces Plasmodium LS burden in an apoptosis-independent manner. Here, we demonstrate that increased P53 is unable to control parasite burden during NOX1 or TFR1 knockdown, or in the presence of ROS scavenging or when lipid peroxidation is blocked. Additionally, SLC7a11 inhibitors Erastin and Sorafenib reduce infection. Thus, blocking the host SLC7a11-GPX4 pathway serves to selectively elevate lipid peroxides in infected cells, which localize within the parasite and lead to the elimination of liver stage parasites.


Amino Acid Transport System y+/metabolism , Lipid Peroxidation , Liver Diseases/metabolism , Liver Diseases/parasitology , Malaria/metabolism , Amino Acid Transport System y+/antagonists & inhibitors , Animals , Cell Line , Cells, Cultured , Ferroptosis , Mice, Inbred C57BL , Mice, Knockout , NADPH Oxidase 1/genetics , Phospholipid Hydroperoxide Glutathione Peroxidase/antagonists & inhibitors , Phospholipid Hydroperoxide Glutathione Peroxidase/metabolism , Reactive Oxygen Species/metabolism , Receptors, Transferrin/metabolism , Signal Transduction , Tumor Suppressor Protein p53/metabolism
16.
Cell ; 177(7): 1933-1947.e25, 2019 06 13.
Article En | MEDLINE | ID: mdl-31160049

Heterotrimetic G proteins consist of four subfamilies (Gs, Gi/o, Gq/11, and G12/13) that mediate signaling via G-protein-coupled receptors (GPCRs), principally by receptors binding Gα C termini. G-protein-coupling profiles govern GPCR-induced cellular responses, yet receptor sequence selectivity determinants remain elusive. Here, we systematically quantified ligand-induced interactions between 148 GPCRs and all 11 unique Gα subunit C termini. For each receptor, we probed chimeric Gα subunit activation via a transforming growth factor-α (TGF-α) shedding response in HEK293 cells lacking endogenous Gq/11 and G12/13 proteins, and complemented G-protein-coupling profiles through a NanoBiT-G-protein dissociation assay. Interrogation of the dataset identified sequence-based coupling specificity features, inside and outside the transmembrane domain, which we used to develop a coupling predictor that outperforms previous methods. We used the predictor to engineer designer GPCRs selectively coupled to G12. This dataset of fine-tuned signaling mechanisms for diverse GPCRs is a valuable resource for research in GPCR signaling.


Heterotrimeric GTP-Binding Proteins/metabolism , Models, Biological , Receptors, G-Protein-Coupled/metabolism , Signal Transduction , Female , HEK293 Cells , Heterotrimeric GTP-Binding Proteins/genetics , Humans , Male , PC-3 Cells , Receptors, G-Protein-Coupled/genetics
17.
Cell Rep ; 26(12): 3391-3399.e4, 2019 03 19.
Article En | MEDLINE | ID: mdl-30893610

Plasmodium parasites are highly selective when infecting hepatocytes and induce many changes within the host cell upon infection. While several host cell factors have been identified that are important for liver infection, our understanding of what facilitates the maintenance of infection remains incomplete. Here, we describe a role for phosphorylated ribosomal protein S6 (Ser235/236) (p-RPS6) in Plasmodium yoelii-infected hepatocytes. Blocking RPS6 phosphorylation prior to infection decreases the number of liver stage parasites within 24 h. Infected hepatocytes exhibit elevated levels of p-RPS6 while simultaneously abrogating the induction of phosphorylation of RPS6 in response to insulin stimulation. This is in contrast with the regulation of p-RPS6 by Toxoplasma gondii, which elevates levels of p-RPS6 after infection but does not alter the response to insulin. Our data support a model in which RPS6 phosphorylation is uncoupled from canonical regulators in Plasmodium-infected hepatocytes and is relied on by the parasite to maintain infection.


Hepatocytes/metabolism , Malaria/metabolism , Plasmodium yoelii/metabolism , Ribosomal Protein S6/metabolism , Animals , Cell Line , Hepatocytes/parasitology , Hepatocytes/pathology , Humans , Malaria/pathology , Mice , Mice, Inbred BALB C , Phosphorylation , Toxoplasma/metabolism , Toxoplasmosis/metabolism , Toxoplasmosis/pathology
18.
Cancer Cell ; 35(3): 457-472.e5, 2019 03 18.
Article En | MEDLINE | ID: mdl-30773340

Activating mutations in GNAQ/GNA11, encoding Gαq G proteins, are initiating oncogenic events in uveal melanoma (UM). However, there are no effective therapies for UM. Using an integrated bioinformatics pipeline, we found that PTK2, encoding focal adhesion kinase (FAK), represents a candidate synthetic lethal gene with GNAQ activation. We show that Gαq activates FAK through TRIO-RhoA non-canonical Gαq-signaling, and genetic ablation or pharmacological inhibition of FAK inhibits UM growth. Analysis of the FAK-regulated transcriptome demonstrated that GNAQ stimulates YAP through FAK. Dissection of the underlying mechanism revealed that FAK regulates YAP by tyrosine phosphorylation of MOB1, inhibiting core Hippo signaling. Our findings establish FAK as a potential therapeutic target for UM and other Gαq-driven pathophysiologies that involve unrestrained YAP function.


Focal Adhesion Kinase 1/metabolism , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , Genes, Lethal , Melanoma/metabolism , Signal Transduction , Uveal Neoplasms/metabolism , Animals , Cell Line, Tumor , Cell Proliferation , Computational Biology , Hippo Signaling Pathway , Humans , Mice , Neoplasm Transplantation , Phosphorylation , Prognosis , Protein Serine-Threonine Kinases/metabolism , Survival Analysis
19.
Sci Signal ; 12(569)2019 02 19.
Article En | MEDLINE | ID: mdl-30783010

The C-terminal guanine nucleotide exchange factor (GEF) module of Trio (TrioC) transfers signals from the Gαq/11 subfamily of heterotrimeric G proteins to the small guanosine triphosphatase (GTPase) RhoA, enabling Gαq/11-coupled G protein-coupled receptors (GPCRs) to control downstream events, such as cell motility and gene transcription. This conserved signal transduction axis is crucial for tumor growth in uveal melanoma. Previous studies indicate that the GEF activity of the TrioC module is autoinhibited, with release of autoinhibition upon Gαq/11 binding. Here, we determined the crystal structure of TrioC in its basal state and found that the pleckstrin homology (PH) domain interacts with the Dbl homology (DH) domain in a manner that occludes the Rho GTPase binding site, thereby suggesting the molecular basis of TrioC autoinhibition. Biochemical and biophysical assays revealed that disruption of the autoinhibited conformation destabilized and activated the TrioC module in vitro. Last, mutations in the DH-PH interface found in patients with cancer activated TrioC and, in the context of full-length Trio, led to increased abundance of guanosine triphosphate-bound RhoA (RhoA·GTP) in human cells. These mutations increase mitogenic signaling through the RhoA axis and, therefore, may represent cancer drivers operating in a Gαq/11-independent manner.


GTP-Binding Protein alpha Subunits, Gq-G11/chemistry , Protein Domains , Rho Guanine Nucleotide Exchange Factors/chemistry , rhoA GTP-Binding Protein/chemistry , Binding Sites/genetics , Carcinogenesis/genetics , Cell Line, Tumor , Crystallography, X-Ray , GTP-Binding Protein alpha Subunits, Gq-G11/genetics , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , Guanosine Triphosphate/chemistry , Guanosine Triphosphate/metabolism , HEK293 Cells , Humans , Melanoma/genetics , Melanoma/pathology , Models, Molecular , Mutation , Protein Binding , Rho Guanine Nucleotide Exchange Factors/genetics , Rho Guanine Nucleotide Exchange Factors/metabolism , Signal Transduction/genetics , Uveal Neoplasms/genetics , Uveal Neoplasms/pathology , rhoA GTP-Binding Protein/genetics , rhoA GTP-Binding Protein/metabolism
20.
Nat Commun ; 8(1): 1232, 2017 11 01.
Article En | MEDLINE | ID: mdl-29089541

Plasmodium parasites have extensive needs from their host hepatocytes during the obligate liver stage of infection, yet there remains sparse knowledge of specific host regulators. Here we assess 34 host-targeted kinase inhibitors for their capacity to eliminate Plasmodium yoelii-infected hepatocytes. Using pre-existing activity profiles of each inhibitor, we generate a predictive computational model that identifies host kinases, which facilitate Plasmodium yoelii liver stage infection. We predict 47 kinases, including novel and previously described kinases that impact infection. The impact of a subset of kinases is experimentally validated, including Receptor Tyrosine Kinases, members of the MAP Kinase cascade, and WEE1. Our approach also predicts host-targeted kinase inhibitors of infection, including compounds already used in humans. Three of these compounds, VX-680, Roscovitine and Sunitinib, each eliminate >85% of infection. Our approach is well-suited to uncover key host determinants of infection in difficult model systems, including field-isolated parasites and/or emerging pathogens.


Liver/drug effects , Malaria/prevention & control , Plasmodium yoelii/drug effects , Protein Kinase Inhibitors/pharmacology , Animals , Cell Line, Tumor , HEK293 Cells , Hepatocytes/drug effects , Hepatocytes/enzymology , Hepatocytes/parasitology , Host-Parasite Interactions/drug effects , Humans , Indoles/pharmacology , Liver/enzymology , Liver/parasitology , Malaria/enzymology , Malaria/parasitology , Mice , Piperazines/pharmacology , Plasmodium yoelii/physiology , Protein Kinases/genetics , Protein Kinases/metabolism , Purines/pharmacology , Pyrroles/pharmacology , RNA Interference , Roscovitine , Sporozoites/drug effects , Sporozoites/physiology , Sunitinib
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