RESUMO
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.
Assuntos
Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Modelos Biológicos , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Feminino , Células HEK293 , Proteínas Heterotriméricas de Ligação ao GTP/genética , Humanos , Masculino , Células PC-3 , Receptores Acoplados a Proteínas G/genéticaRESUMO
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.
Assuntos
Carcinogênese , Proteína-Tirosina Quinases de Adesão Focal , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Proteína-Tirosina Quinases de Adesão Focal/genética , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Humanos , Carcinogênese/genéticaRESUMO
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.
Assuntos
Proteínas Quinases Dependentes de AMP Cíclico , Medicina Genômica , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Subunidades alfa Gs de Proteínas de Ligação ao GTP/metabolismo , Humanos , Mutação , Transdução de SinaisRESUMO
Eliminating malaria parasites during the asymptomatic but obligate liver stages (LSs) of infection would stop disease and subsequent transmission. Unfortunately, only a single licensed drug that targets all LSs, Primaquine, is available. Targeting host proteins might significantly expand the repertoire of prophylactic drugs against malaria. Here, we demonstrate that both Bcl-2 inhibitors and P53 agonists dramatically reduce LS burden in a mouse malaria model in vitro and in vivo by altering the activity of key hepatocyte factors on which the parasite relies. Bcl-2 inhibitors act primarily by inducing apoptosis in infected hepatocytes, whereas P53 agonists eliminate parasites in an apoptosis-independent fashion. In combination, Bcl-2 inhibitors and P53 agonists act synergistically to delay, and in some cases completely prevent, the onset of blood stage disease. Both families of drugs are highly effective at doses that do not cause substantial hepatocyte cell death in vitro or liver damage in vivo. P53 agonists and Bcl-2 inhibitors were also effective when administered to humanized mice infected with Plasmodium falciparum. Our data demonstrate that host-based prophylaxis could be developed into an effective intervention strategy that eliminates LS parasites before the onset of clinical disease and thus opens a new avenue to prevent malaria.
Assuntos
Antimaláricos/farmacologia , Estágios do Ciclo de Vida/efeitos dos fármacos , Fígado/parasitologia , Malária/parasitologia , Plasmodium/efeitos dos fármacos , Plasmodium/fisiologia , Profilaxia Pós-Exposição , Animais , Antimaláricos/administração & dosagem , Linhagem Celular , Modelos Animais de Doenças , Feminino , Imidazóis/administração & dosagem , Imidazóis/farmacologia , Indóis , Malária/tratamento farmacológico , Malária/metabolismo , Malária/prevenção & controle , Malária Falciparum/tratamento farmacológico , Malária Falciparum/metabolismo , Malária Falciparum/parasitologia , Malária Falciparum/prevenção & controle , Camundongos , Camundongos Transgênicos , Carga Parasitária , Piperazinas/administração & dosagem , Piperazinas/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Pirróis/administração & dosagem , Pirróis/farmacologia , Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína Supressora de Tumor p53/metabolismoRESUMO
After transmission by Anopheles mosquitoes, Plasmodium sporozoites travel to the liver, infect hepatocytes, and rapidly develop as intrahepatocytic liver stages (LS). Rodent models of malaria exhibit large differences in the magnitude of liver infection, both between parasite species and between strains of mice. This has been mainly attributed to differences in innate immune responses and parasite infectivity. Here, we report that BALB/cByJ mice are more susceptible to Plasmodium yoelii preerythrocytic infection than BALB/cJ mice. This difference occurs at the level of early hepatocyte infection, but expression levels of reported host factors that are involved in infection do not correlate with susceptibility. Interestingly, BALB/cByJ hepatocytes are more frequently polyploid; thus, their susceptibility converges on the previously observed preference of sporozoites to infect polyploid hepatocytes. Gene expression analysis demonstrates hepatocyte-specific differences in mRNA abundance for numerous genes between BALB/cByJ and BALB/cJ mice, some of which encode hepatocyte surface molecules. These data suggest that a yet-unknown receptor for sporozoite infection, present at elevated levels on BALB/cByJ hepatocytes and also polyploid hepatocytes, might facilitate Plasmodium liver infection.
Assuntos
Suscetibilidade a Doenças , Endocitose , Hepatócitos/parasitologia , Malária/imunologia , Malária/parasitologia , Plasmodium yoelii/fisiologia , Animais , Feminino , Perfilação da Expressão Gênica , Camundongos Endogâmicos BALB CRESUMO
Plasmodium sporozoites develop within oocysts in the mosquito midgut wall and then migrate to the salivary glands. After transmission, they embark on a complex journey to the mammalian liver, where they infect hepatocytes. Proteins on the sporozoite surface likely mediate multiple steps of this journey, yet only a few sporozoite surface proteins have been described. Here, we characterize a novel, conserved sporozoite surface protein (SSP3) in the rodent malaria parasite Plasmodium yoelii. SSP3 is a putative type I transmembrane protein unique to Plasmodium. By using epitope tagging and SSP3-specific antibodies in conjunction with immunofluorescence microscopy, we showed that SSP3 is expressed in mosquito midgut oocyst sporozoites, exhibiting an intracellular localization. In sporozoites derived from the mosquito salivary glands, however, SSP3 localized predominantly to the sporozoite surface as determined by immunoelectron microscopy. However, the ectodomain of SSP3 appeared to be inaccessible to antibodies in nonpermeabilized salivary gland sporozoites. Antibody-induced shedding of the major surface protein circumsporozoite protein (CSP) exposed the SSP3 ectodomain to antibodies in some sporozoites. Targeted deletion of SSP3 adversely affected in vitro sporozoite gliding motility, which, surprisingly, impacted neither their cell traversal capacity, host cell invasion in vitro, nor infectivity in vivo. Together, these data reveal a previously unappreciated complexity of the Plasmodium sporozoite surface proteome and the roles of surface proteins in distinct biological activities of sporozoites.
Assuntos
Regulação da Expressão Gênica/fisiologia , Proteínas de Membrana/metabolismo , Plasmodium yoelii/metabolismo , Proteínas de Protozoários/metabolismo , Esporozoítos/metabolismo , Animais , Anticorpos Antiprotozoários , Epitopos , Feminino , Deleção de Genes , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos BALB C , Movimento , Plasmodium yoelii/genética , Transporte Proteico , Proteínas de Protozoários/genéticaRESUMO
Mathematical models of biochemical reaction networks are an important and emerging tool for the study of cell signaling networks involved in disease processes. One promising potential application of such mathematical models is the study of how disease-causing mutations promote the signaling phenotype that contributes to the disease. It is commonly assumed that one must have a thorough characterization of the network readily available for mathematical modeling to be useful, but we hypothesized that mathematical modeling could be useful when there is incomplete knowledge and that it could be a tool for discovery that opens new areas for further exploration. In the present study, we first develop a mechanistic mathematical model of a G-protein coupled receptor signaling network that is mutated in almost all cases of uveal melanoma and use model-driven explorations to uncover and explore multiple new areas for investigating this disease. Modeling the two major, mutually-exclusive, oncogenic mutations (Gαq/11 and CysLT2R) revealed the potential for previously unknown qualitative differences between seemingly interchangeable disease-promoting mutations, and our experiments confirmed oncogenic CysLT2R was impaired at activating the FAK/YAP/TAZ pathway relative to Gαq/11. This led us to hypothesize that CYSLTR2 mutations in UM must co-occur with other mutations to activate FAK/YAP/TAZ signaling, and our bioinformatic analysis uncovers a role for co-occurring mutations involving the plexin/semaphorin pathway, which has been shown capable of activating this pathway. Overall, this work highlights the power of mechanism-based computational systems biology as a discovery tool that can leverage available information to open new research areas.
Assuntos
Mutação , Receptores Acoplados a Proteínas G , Transdução de Sinais , Humanos , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Mutação/genética , Neoplasias Uveais/genética , Neoplasias Uveais/metabolismo , Biologia de Sistemas/métodos , Modelos Biológicos , Melanoma/genética , Melanoma/metabolismo , Proteínas de Ligação ao GTP/genética , Proteínas de Ligação ao GTP/metabolismoRESUMO
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 yet 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 putative 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)), but we also uncovered many novel kinases. Our methods also predicted host 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 may differ substantially depending on which receptors are bound and the life cycle stage that is internalized. In addition, using our screen, we identified kinases that appear to preferentially regulate the uptake of parasites over beads, indicating that the methods required for Leishmania to be internalized by macrophages may 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.
RESUMO
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 yet 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 putative 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)), but we also uncovered many novel kinases. Our methods also predicted host 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 may differ substantially depending on which receptors are bound and the life cycle stage that is internalized. In addition, using our screen, we identified kinases that appear to preferentially regulate the uptake of parasites over beads, indicating that the methods required for Leishmania to be internalized by macrophages may 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.
RESUMO
The comprehensive genomic analysis of the head and neck squamous cell carcinoma (HNSCC) oncogenome revealed the frequent loss of p16INK4A (CDKN2A) and amplification of cyclin D1 genes in most human papillomavirus-negative HNSCC lesions. However, cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have shown modest effects in the clinic. The aberrant activation of the PI3K/mTOR pathway is highly prevalent in HNSCC, and recent clinical trials have shown promising clinical efficacy of mTOR inhibitors (mTORi) in the neoadjuvant and adjuvant settings but not in patients with advanced HNSCC. By implementing a kinome-wide CRISPR/Cas9 screen, we identified cell-cycle inhibition as a synthetic lethal target for mTORis. A combination of mTORi and palbociclib, a CDK4/6-specific inhibitor, showed strong synergism in HNSCC-derived cells in vitro and in vivo. Remarkably, we found that an adaptive increase in cyclin E1 (CCNE1) expression upon palbociclib treatment underlies the rapid acquired resistance to this CDK4/6 inhibitor. Mechanistically, mTORi inhibits the formation of eIF4G-CCNE1 mRNA complexes, with the consequent reduction in mRNA translation and CCNE1 protein expression. Our findings suggest that mTORi reverts the adaptive resistance to palbociclib. This provides a multimodal therapeutic option for HNSCC by cotargeting mTOR and CDK4/6, which in turn may halt the emergence of palbociclib resistance. SIGNIFICANCE: A kinome-wide CRISPR/Cas9 screen identified cell-cycle inhibition as a synthetic lethal target of mTORis. A combination of mTORi and palbociclib, a CDK4/6-specific inhibitor, showed strong synergistic effects in HNSCC. Mechanistically, mTORis inhibited palbociclib-induced increase in CCNE1.
Assuntos
Sistemas CRISPR-Cas , Quinase 4 Dependente de Ciclina , Quinase 6 Dependente de Ciclina , Resistencia a Medicamentos Antineoplásicos , Neoplasias de Cabeça e Pescoço , Piperazinas , Piridinas , Carcinoma de Células Escamosas de Cabeça e Pescoço , Humanos , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 4 Dependente de Ciclina/genética , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/genética , Quinase 6 Dependente de Ciclina/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Piperazinas/farmacologia , Piperazinas/uso terapêutico , Piridinas/farmacologia , Camundongos , Animais , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/metabolismo , Linhagem Celular Tumoral , Inibidores de MTOR/farmacologia , Inibidores de MTOR/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Serina-Treonina Quinases TOR/metabolismo , Ciclina E/genética , Ciclina E/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , Mutações Sintéticas Letais , Proteínas OncogênicasRESUMO
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.
Assuntos
Classe Ib de Fosfatidilinositol 3-Quinase , Leucemia Mieloide Aguda , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/genética , Humanos , Animais , Camundongos , Transdução de Sinais/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Classe Ib de Fosfatidilinositol 3-Quinase/metabolismo , Classe Ib de Fosfatidilinositol 3-Quinase/genética , Linhagem Celular Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto , Sulfonamidas/farmacologia , Sulfonamidas/uso terapêutico , Proteólise/efeitos dos fármacos , Feminino , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêuticoRESUMO
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.
Assuntos
Glutamina , Proteínas Heterotriméricas de Ligação ao GTP , Domínio Catalítico , Glutamina/genética , Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Mutação , Guanosina Trifosfato/químicaRESUMO
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.
Assuntos
Melanoma , Neoplasias Cutâneas , Neoplasias Uveais , Animais , Camundongos , Melanoma/tratamento farmacológico , Melanoma/genética , Melanoma/patologia , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/uso terapêutico , Avaliação Pré-Clínica de Medicamentos , Neoplasias Uveais/tratamento farmacológico , Neoplasias Uveais/genética , Neoplasias Uveais/metabolismo , Inibidores de Proteínas Quinases/farmacologiaRESUMO
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.
Assuntos
Malária , Proteínas Associadas aos Microtúbulos , Microtúbulos , Sistemas CRISPR-Cas , Humanos , Fígado/metabolismo , Fígado/parasitologia , Malária/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Plasmodium/metabolismo , Tubulina (Proteína)/metabolismoRESUMO
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.
Assuntos
Ciclosporina , Células Endoteliais , Ciclosporina/toxicidade , Humanos , Imunossupressores/toxicidade , Rim , MicrovasosRESUMO
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.
Assuntos
Neoplasias de Mama Triplo Negativas , Adesão Celular , Proteína-Tirosina Quinases de Adesão Focal , Via de Sinalização Hippo , Humanos , Transdução de Sinais , Neoplasias de Mama Triplo Negativas/genéticaRESUMO
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.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Receptores ErbB/genética , Via de Sinalização Hippo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Tirosina/metabolismo , Animais , Receptores ErbB/metabolismo , Feminino , Regulação da Expressão Gênica , Genes erbB-1/genética , Camundongos , FosforilaçãoRESUMO
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.
Assuntos
Quinase 1 de Adesão Focal/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Mutação com Ganho de Função , Testes Genéticos/métodos , Sistema de Sinalização das MAP Quinases/genética , Melanoma/genética , Melanoma/terapia , Terapia de Alvo Molecular , Neoplasias Uveais/genética , Neoplasias Uveais/terapia , Animais , Terapia Combinada , Feminino , Células HEK293 , Humanos , Sistema de Sinalização das MAP Quinases/fisiologia , Camundongos Endogâmicos NOD , Camundongos SCID , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
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.
Assuntos
Carcinogênese , Progressão da Doença , Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , HumanosRESUMO
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.