RESUMEN
MYC enhances protein synthesis by regulating genes involved in ribosome biogenesis and protein translation. Here, we show that MYC-induced protein translation is mediated by the transcription factor aryl hydrocarbon receptor (AHR), which is induced by MYC in colonic cells. AHR promotes protein synthesis by activating the transcription of genes required for ribosome biogenesis and protein translation, including OGFOD1 and NOLC1. Using surface sensing of translation (SUnSET) to measure global protein translation, we found that silencing AHR or its targets diminishes protein synthesis. Therefore, targeting AHR or its downstream pathways could provide a novel approach to limit biomass production in MYC-driven tumors.
Asunto(s)
Nucléolo Celular/metabolismo , Biosíntesis de Proteínas , Proteínas Proto-Oncogénicas c-myc/metabolismo , Receptores de Hidrocarburo de Aril/fisiología , Animales , Línea Celular , Nucléolo Celular/genética , Células Cultivadas , Neoplasias del Colon/genética , Neoplasias del Colon/metabolismo , Humanos , Proteínas Proto-Oncogénicas c-myc/genética , Ratas , Receptores de Hidrocarburo de Aril/biosíntesis , Receptores de Hidrocarburo de Aril/genética , Activación TranscripcionalRESUMEN
The common participation of oncogenic KRAS proteins in many of the most lethal human cancers, together with the ease of detecting somatic KRAS mutant alleles in patient samples, has spurred persistent and intensive efforts to develop drugs that inhibit KRAS activity. However, advances have been hindered by the pervasive inter- and intra-lineage diversity in the targetable mechanisms that underlie KRAS-driven cancers, limited pharmacological accessibility of many candidate synthetic-lethal interactions and the swift emergence of unanticipated resistance mechanisms to otherwise effective targeted therapies. Here we demonstrate the acute and specific cell-autonomous addiction of KRAS-mutant non-small-cell lung cancer cells to receptor-dependent nuclear export. A multi-genomic, data-driven approach, utilizing 106 human non-small-cell lung cancer cell lines, was used to interrogate 4,725 biological processes with 39,760 short interfering RNA pools for those selectively required for the survival of KRAS-mutant cells that harbour a broad spectrum of phenotypic variation. Nuclear transport machinery was the sole process-level discriminator of statistical significance. Chemical perturbation of the nuclear export receptor XPO1 (also known as CRM1), with a clinically available drug, revealed a robust synthetic-lethal interaction with native or engineered oncogenic KRAS both in vitro and in vivo. The primary mechanism underpinning XPO1 inhibitor sensitivity was intolerance to the accumulation of nuclear IκBα (also known as NFKBIA), with consequent inhibition of NFκB transcription factor activity. Intrinsic resistance associated with concurrent FSTL5 mutations was detected and determined to be a consequence of YAP1 activation via a previously unappreciated FSTL5-Hippo pathway regulatory axis. This occurs in approximately 17% of KRAS-mutant lung cancers, and can be overcome with the co-administration of a YAP1-TEAD inhibitor. These findings indicate that clinically available XPO1 inhibitors are a promising therapeutic strategy for a considerable cohort of patients with lung cancer when coupled to genomics-guided patient selection and observation.
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Transporte Activo de Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Carioferinas/antagonistas & inhibidores , Carioferinas/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/genética , Receptores Citoplasmáticos y Nucleares/antagonistas & inhibidores , Receptores Citoplasmáticos y Nucleares/metabolismo , Proteínas Adaptadoras Transductoras de Señales/antagonistas & inhibidores , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Línea Celular Tumoral , Núcleo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Proteínas de Unión al ADN/antagonistas & inhibidores , Proteínas de Unión al ADN/metabolismo , Femenino , Proteínas Relacionadas con la Folistatina/genética , Genes Letales/genética , Vía de Señalización Hippo , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/patología , Ratones , Mutación , Inhibidor NF-kappaB alfa/metabolismo , FN-kappa B/antagonistas & inhibidores , FN-kappa B/metabolismo , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Nucleares/metabolismo , Fosfoproteínas/antagonistas & inhibidores , Fosfoproteínas/metabolismo , Porfirinas/farmacología , Proteínas Serina-Treonina Quinasas/metabolismo , Interferencia de ARN , ARN Interferente Pequeño , Transducción de Señal , Factores de Transcripción de Dominio TEA , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/metabolismo , Verteporfina , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas Señalizadoras YAP , Proteína Exportina 1RESUMEN
The generation of new blood vessels from the existing vasculature is a dynamic and complex mechanism known as angiogenesis. Angiogenesis occurs during the entire lifespan of vertebrates and participates in many physiological processes. Furthermore, angiogenesis is also actively involved in many human diseases and disorders, including cancer, obesity and infections. Several inter-connected molecular pathways regulate angiogenesis, and post-translational modifications, such as phosphorylation, ubiquitination and SUMOylation, tightly regulate these mechanisms and play a key role in the control of the process. Here, we describe in detail the roles of ubiquitination and SUMOylation in the regulation of angiogenesis.
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Células Endoteliales/metabolismo , Neovascularización Patológica/metabolismo , Neovascularización Fisiológica , Sumoilación , Ubiquitinación , Animales , Células Endoteliales/enzimología , Humanos , Neovascularización Patológica/enzimología , Neovascularización Fisiológica/genética , Neovascularización Fisiológica/fisiología , Fosforilación , Procesamiento Proteico-Postraduccional/genética , Procesamiento Proteico-Postraduccional/fisiología , Receptores Notch/genética , Receptores Notch/metabolismo , Receptores de Factores de Crecimiento Endotelial Vascular/genética , Receptores de Factores de Crecimiento Endotelial Vascular/metabolismo , Transducción de Señal/genética , Transducción de Señal/fisiologíaRESUMEN
The protein inhibitor of activated STAT-1 (PIAS1) is one of the few known SUMO E3 ligases. PIAS1 has been implicated in several biological processes including repression of innate immunity and DNA repair. However, PIAS1 function during development and tissue differentiation has not been studied. Here, we report that Pias1 is required for proper embryonic development. Approximately 90% of Pias1 null embryos die in utero between E10.5 and E12.5. We found significant apoptosis within the yolk sac (YS) blood vessels and concomitant loss of red blood cells (RBCs) resulting in profound anemia. In addition, Pias1 loss impairs YS angiogenesis and results in defective capillary plexus formation and blood vessel occlusions. Moreover, heart development is impaired as a result of loss of myocardium muscle mass. Accordingly, we found that Pias1 expression in primary myoblasts enhances the induction of cardiac muscle genes MyoD, Myogenin and Myomaker. PIAS1 protein regulation of cardiac gene transcription is dependent on transcription factors Myocardin and Gata-4. Finally, endothelial cell specific inactivation of Pias1 in vivo impairs YS erythrogenesis, angiogenesis and recapitulates loss of myocardium muscle mass. However, these defects are not sufficient to recapitulate the lethal phenotype of Pias1 null embryos. These findings highlight Pias1 as an essential gene for YS erythropoiesis and vasculogenesis in vivo.
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Desarrollo Embrionario/fisiología , Eritropoyesis/fisiología , Neovascularización Fisiológica/fisiología , Proteínas Inhibidoras de STAT Activados/fisiología , Animales , Diferenciación Celular , Células Cultivadas , Desarrollo Embrionario/genética , Células Endoteliales/citología , Eritropoyesis/genética , Retardo del Crecimiento Fetal/genética , Retardo del Crecimiento Fetal/patología , Regulación del Desarrollo de la Expresión Génica , Genes Letales , Estratos Germinativos/citología , Corazón/embriología , Macrófagos/citología , Ratones , Mielopoyesis/genética , Mielopoyesis/fisiología , Neovascularización Fisiológica/genética , Penetrancia , Proteínas Inhibidoras de STAT Activados/deficiencia , Proteínas Inhibidoras de STAT Activados/genética , Sumoilación , Factores de Transcripción/fisiología , Saco Vitelino/irrigación sanguínea , Saco Vitelino/crecimiento & desarrolloRESUMEN
Intrinsic resistance to targeted therapeutics in PTEN-deficient glioblastoma (GBM) is mediated by redundant signaling networks that sustain critical metabolic functions. Here we demonstrate that coordinated inhibition of the ribosomal protein S6 kinase 1 (S6K1) and the receptor tyrosine kinase AXL using LY-2584702 and BMS-777607 can overcome network redundancy to reduce GBM tumor growth. This combination of S6K1 and AXL inhibition suppressed glucose flux to pyrimidine biosynthesis. Genetic inactivation studies to map the signaling network indicated that both S6K1 and S6K2 transmit growth signals in PTEN-deficient GBM. Kinome-wide ATP binding analysis in inhibitor-treated cells revealed that LY-2584702 directly inhibited S6K1, and substrate phosphorylation studies showed that BMS-777607 inactivation of upstream AXL collaborated to reduce S6K2-mediated signal transduction. Thus, combination targeting of S6K1 and AXL provides a kinase-directed therapeutic approach that circumvents signal transduction redundancy to interrupt metabolic function and reduce growth of PTEN-deficient GBM.
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The promyelocytic leukemia-retinoic acid receptor alpha (PML-RARalpha) protein of acute promyelocytic leukemia (APL) is oncogenic in vivo. It has been hypothesized that the ability of PML-RARalpha to inhibit RARalpha function through PML-dependent aberrant recruitment of histone deacetylases (HDACs) and chromatin remodeling is the key initiating event for leukemogenesis. To elucidate the role of HDAC in this process, we have generated HDAC1-RARalpha fusion proteins and tested their activity and oncogenicity in vitro and in vivo in transgenic mice (TM). In parallel, we studied the in vivo leukemogenic potential of dominant negative (DN) and truncated RARalpha mutants, as well as that of PML-RARalpha mutants that are insensitive to retinoic acid. Surprisingly, although HDAC1-RARalpha did act as a bona fide DN RARalpha mutant in cellular in vitro and in cell culture, this fusion protein, as well as other DN RARalpha mutants, did not cause a block in myeloid differentiation in vivo in TM and were not leukemogenic. Comparative analysis of these TM and of TM/PML(-/-) and p53(-/-) compound mutants lends support to a model by which the RARalpha and PML blockade is necessary, but not sufficient, for leukemogenesis and the PML domain of the fusion protein provides unique functions that are required for leukemia initiation.
Asunto(s)
Histona Desacetilasas/metabolismo , Leucemia Promielocítica Aguda/enzimología , Leucemia Promielocítica Aguda/etiología , Receptores de Ácido Retinoico/antagonistas & inhibidores , Receptores de Ácido Retinoico/fisiología , Animales , Línea Celular , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Ratones , Ratones Desnudos , Ratones Transgénicos , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/fisiología , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Nucleares/genética , Proteínas Nucleares/fisiología , Proteína de la Leucemia Promielocítica , Receptores de Ácido Retinoico/genética , Receptor alfa de Ácido Retinoico , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/genética , Factores de Transcripción/fisiología , Proteínas Supresoras de Tumor/antagonistas & inhibidores , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/fisiologíaRESUMEN
The proto-oncogene AKT (also known as PKB) is activated in many human cancers, mostly owing to loss of the PTEN tumour suppressor. In such tumours, AKT becomes enriched at cell membranes where it is activated by phosphorylation. Yet many targets inhibited by phosphorylated AKT (for example, the FOXO transcription factors) are nuclear; it has remained unclear how relevant nuclear phosphorylated AKT (pAKT) function is for tumorigenesis. Here we show that the PMLtumour suppressor prevents cancer by inactivating pAKT inside the nucleus. We find in a mouse model that Pml loss markedly accelerates tumour onset, incidence and progression in Pten-heterozygous mutants, and leads to female sterility with features that recapitulate the phenotype of Foxo3a knockout mice. We show that Pml deficiency on its own leads to tumorigenesis in the prostate, a tissue that is exquisitely sensitive to pAkt levels, and demonstrate that Pml specifically recruits the Akt phosphatase PP2a as well as pAkt into Pml nuclear bodies. Notably, we find that Pml-null cells are impaired in PP2a phosphatase activity towards Akt, and thus accumulate nuclear pAkt. As a consequence, the progressive reduction in Pml dose leads to inactivation of Foxo3a-mediated transcription of proapoptotic Bim and the cell cycle inhibitor p27(kip1). Our results demonstrate that Pml orchestrates a nuclear tumour suppressor network for inactivation of nuclear pAkt, and thus highlight the importance of AKT compartmentalization in human cancer pathogenesis and treatment.
Asunto(s)
Núcleo Celular/enzimología , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-akt/metabolismo , Factores de Transcripción/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Células Cultivadas , Femenino , Ratones , Proteínas de Neoplasias/deficiencia , Proteínas de Neoplasias/genética , Proteínas Nucleares/deficiencia , Proteínas Nucleares/genética , Fosfohidrolasa PTEN/deficiencia , Fosfohidrolasa PTEN/genética , Fosfoproteínas Fosfatasas/metabolismo , Fosforilación , Proteína de la Leucemia Promielocítica , Transporte de Proteínas , Proto-Oncogenes Mas , Factores de Transcripción/deficiencia , Factores de Transcripción/genética , Proteínas Supresoras de Tumor/deficiencia , Proteínas Supresoras de Tumor/genéticaRESUMEN
Ferroptosis has emerged as a new type of programmed cell death that can be harnessed for cancer therapy. The concept of ferroptosis was for the first time proposed in in the early 2000s, as an iron-dependent mode of regulated cell death caused by unrestricted lipid peroxidation (LPO) and subsequent plasma membrane rupture. Since the discovery and characterization of ferroptosis, a wealth of research has improved our understanding of the main pathways regulating this process, leading to both the repurposing and the development of small molecules. However, ferroptosis is still little understood and several aspects remain to be investigated. For instance, it is unclear whether specific oncogenes, cells of origin or tumor niches impose specific susceptibility/resistance to ferroptosis or if there are some ferroptosis-related genes that may be used as bona fide pan-cancer targetable dependencies. In this context, even though RAS-driven cancer cell lines seemed to be selectively sensitive to ferroptosis inducers, subsequent studies have questioned these results, indicating that in some cases mutant RAS is necessary, but not sufficient to induce ferroptosis. In this perspective, based on publicly available genomic screening data and the literature, we discuss the relationship between RAS-mutation and ferroptosis susceptibility in cancer.
RESUMEN
Mutant KRAS (KM), the most common oncogene in lung cancer (LC), regulates fatty acid (FA) metabolism. However, the role of FA in LC tumorigenesis is still not sufficiently characterized. Here, we show that KMLC has a specific lipid profile, with high triacylglycerides and phosphatidylcholines (PC). We demonstrate that FASN, the rate-limiting enzyme in FA synthesis, while being dispensable in EGFR-mutant or wild-type KRAS LC, is required for the viability of KMLC cells. Integrating lipidomic, transcriptomic and functional analyses, we demonstrate that FASN provides saturated and monounsaturated FA to the Lands cycle, the process remodeling oxidized phospholipids, such as PC. Accordingly, blocking either FASN or the Lands cycle in KMLC, promotes ferroptosis, a reactive oxygen species (ROS)- and iron-dependent cell death, characterized by the intracellular accumulation of oxidation-prone PC. Our work indicates that KM dictates a dependency on newly synthesized FA to escape ferroptosis, establishing a targetable vulnerability in KMLC.
Asunto(s)
Ferroptosis , Neoplasias Pulmonares , Ferroptosis/genética , Humanos , Metabolismo de los Lípidos/genética , Lipogénesis/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Fosfatidilcolinas , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismoRESUMEN
The promyelocytic leukaemia (PML) tumour-suppressor protein potentiates p53 function by regulating post-translational modifications, such as CBP-dependent acetylation and Chk2-dependent phosphorylation, in the PML-Nuclear Body (NB). PML was recently shown to interact with the p53 ubiquitin-ligase Mdm2 (refs 4-6); however, the mechanism by which PML regulates Mdm2 remains unclear. Here, we show that PML enhances p53 stability by sequestering Mdm2 to the nucleolus. We found that after DNA damage, PML and Mdm2 accumulate in the nucleolus in an Arf-independent manner. In addition, we found that the nucleolar localization of PML is dependent on ATR activation and phosphorylation of PML by ATR. Notably, in Pml(-/-) cells, sequestration of Mdm2 to the nucleolus was impaired, as well as p53 stabilization and the induction of apoptosis. Furthermore, we demonstrate that PML physically associates with the nucleolar protein L11, and that L11 knockdown impairs the ability of PML to localize to nucleoli after DNA damage. These findings demonstrate an unexpected role of PML in the nucleolar network for tumour suppression.
Asunto(s)
Nucléolo Celular/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Factores de Transcripción/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Factor 1 de Ribosilacion-ADP/genética , Factor 1 de Ribosilacion-ADP/metabolismo , Transporte Activo de Núcleo Celular/genética , Animales , Proteínas de la Ataxia Telangiectasia Mutada , Compartimento Celular/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Línea Celular Transformada , Nucléolo Celular/genética , Células Cultivadas , Fibroblastos , Humanos , Ratones , Células 3T3 NIH , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Fosforilación , Proteína de la Leucemia Promielocítica , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Transporte de Proteínas/genética , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-mdm2 , Estabilidad del ARN/genética , Proteínas Ribosómicas/genética , Proteínas Ribosómicas/metabolismo , Factores de Transcripción/genética , Proteína p53 Supresora de Tumor/genética , Proteínas Supresoras de Tumor/genéticaRESUMEN
HRAS, NRAS and KRAS, collectively referred to as oncogenic RAS, are the most frequently mutated driver proto-oncogenes in cancer. Oncogenic RAS aberrantly rewires metabolic pathways promoting the generation of intracellular reactive oxygen species (ROS). In particular, lipids have gained increasing attention serving critical biological roles as building blocks for cellular membranes, moieties for post-translational protein modifications, signaling molecules and substrates for ß-oxidation. However, thus far, the understanding of lipid metabolism in cancer has been hampered by the lack of sensitive analytical platforms able to identify and quantify such complex molecules and to assess their metabolic flux in vitro and, even more so, in primary tumors. Similarly, the role of ROS in RAS-driven cancer cells has remained elusive. On the one hand, ROS are beneficial to the development and progression of precancerous lesions, by upregulating survival and growth factor signaling, on the other, they promote accumulation of oxidative by-products that decrease the threshold of cancer cells to undergo ferroptosis. Here, we overview the recent advances in the study of the relation between RAS and lipid metabolism, in the context of different cancer types. In particular, we will focus our attention on how lipids and oxidative stress can either promote or sensitize to ferroptosis RAS driven cancers. Finally, we will explore whether this fine balance could be modulated for therapeutic gain.
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Glioblastoma (GBM) is highly resistant to chemotherapies, immune-based therapies, and targeted inhibitors. To identify novel drug targets, we screened orthotopically implanted, patient-derived glioblastoma sphere-forming cells using an RNAi library to probe essential tumor cell metabolic programs. This identified high dependence on mitochondrial fatty acid metabolism. We focused on medium-chain acyl-CoA dehydrogenase (MCAD), which oxidizes medium-chain fatty acids (MCFA), due to its consistently high score and high expression among models and upregulation in GBM compared with normal brain. Beyond the expected energetics impairment, MCAD depletion in primary GBM models induced an irreversible cascade of detrimental metabolic effects characterized by accumulation of unmetabolized MCFAs, which induced lipid peroxidation and oxidative stress, irreversible mitochondrial damage, and apoptosis. Our data uncover a novel protective role for MCAD to clear lipid molecules that may cause lethal cell damage, suggesting that therapeutic targeting of MCFA catabolism may exploit a key metabolic feature of GBM. SIGNIFICANCE: MCAD exerts a protective role to prevent accumulation of toxic metabolic by-products in glioma cells, actively catabolizing lipid species that would otherwise affect mitochondrial integrity and induce cell death. This work represents a first demonstration of a nonenergetic role for dependence on fatty acid metabolism in cancer.This article is highlighted in the In This Issue feature, p. 2659.
Asunto(s)
Acil-CoA Deshidrogenasa , Glioblastoma , Peroxidación de Lípido , Mitocondrias , Acil-CoA Deshidrogenasa/metabolismo , Apoptosis , Ácidos Grasos/metabolismo , Glioblastoma/enzimología , Glioblastoma/genética , Humanos , Mitocondrias/metabolismo , Estrés OxidativoRESUMEN
SUMOylation modifies the interactome, localization, activity, and lifespan of its target proteins. This process regulates several cellular machineries, including transcription, DNA damage repair, cell-cycle progression, and apoptosis. Accordingly, SUMOylation is critical in maintaining cellular homeostasis, and its deregulation leads to the corruption of a plethora of cellular processes that contribute to disease states. Among the proteins involved in SUMOylation, the protein inhibitor of activated STAT (PIAS) E3-ligases were initially described as transcriptional coregulators. Recent findings also indicate that they have a role in regulating protein stability and signaling transduction pathways. PIAS proteins interact with up to 60 cellular partners affecting several cellular processes, most notably immune regulation and DNA repair, but also cellular proliferation and survival. Here, we summarize the current knowledge about their role in tumorigenesis and cancer-related processes. Cancer Res; 77(7); 1542-7. ©2017 AACR.
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Neoplasias/etiología , Proteínas Inhibidoras de STAT Activados/fisiología , Sumoilación , Ubiquitina-Proteína Ligasas/fisiología , Animales , Movimiento Celular , Transición Epitelial-Mesenquimal , Humanos , Neoplasias/patología , Fosfatidilinositol 3-Quinasas/fisiología , Proteínas Proto-Oncogénicas c-myc/fisiología , Proteína p53 Supresora de Tumor/fisiologíaRESUMEN
The sequence of genomic alterations acquired by cancer cells during tumor progression and metastasis is poorly understood. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that integrates cytoskeleton remodeling, mitogenic signaling and cell survival. FAK has previously been reported to undergo nuclear localization during cell migration, cell differentiation and apoptosis. However, the mechanism behind FAK nuclear accumulation and its contribution to tumor progression has remained elusive. We report that amplification of FAK and the SUMO E3 ligase PIAS1 gene loci frequently co-occur in non-small cell lung cancer (NSCLC) cells, and that both gene products are enriched in a subset of primary NSCLCs. We demonstrate that endogenous FAK and PIAS1 proteins interact in the cytoplasm and the cell nucleus of NSCLC cells. Ectopic expression of PIAS1 promotes proteolytic cleavage of the FAK C-terminus, focal adhesion maturation and FAK nuclear localization. Silencing of PIAS1 deregulates focal adhesion turnover, increases susceptibility to apoptosis in vitro and impairs tumor xenograft formation in vivo. Nuclear FAK in turn stimulates gene transcription favoring DNA repair, cell metabolism and cytoskeleton regulation. Consistently, ablation of FAK by CRISPR/Cas9 editing, results in basal DNA damage, susceptibility to ionizing radiation and impaired oxidative phosphorylation. Our findings provide insight into a mechanism regulating FAK cytoplasm-nuclear distribution and demonstrate that FAK activity in the nucleus promotes NSCLC survival and progression by increasing cell-ECM interaction and DNA repair regulation.
RESUMEN
PURPOSE: Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths worldwide due to the limited availability of effective therapeutic options. For instance, there are no effective strategies for NSCLCs that harbor mutant KRAS, the most commonly mutated oncogene in NSCLC. Thus, our purpose was to make progress toward the generation of a novel therapeutic strategy for NSCLC. EXPERIMENTAL DESIGN: We characterized the effects of suppressing focal adhesion kinase (FAK) by RNA interference (RNAi), CRISPR/CAS9 gene editing or pharmacologic approaches in NSCLC cells and in tumor xenografts. In addition, we tested the effects of suppressing FAK in association with ionizing radiation (IR), a standard-of-care treatment modality. RESULTS: FAK is a critical requirement of mutant KRAS NSCLC cells. With functional experiments, we also found that, in mutant KRAS NSCLC cells, FAK inhibition resulted in persistent DNA damage and susceptibility to exposure to IR. Accordingly, administration of IR to FAK-null tumor xenografts causes a profound antitumor effect in vivo CONCLUSIONS: FAK is a novel regulator of DNA damage repair in mutant KRAS NSCLC and its pharmacologic inhibition leads to radiosensitizing effects that could be beneficial in cancer therapy. Our results provide a framework for the rationale clinical testing of FAK inhibitors in NSCLC patients. Clin Cancer Res; 22(23); 5851-63. ©2016 AACR.
Asunto(s)
Daño del ADN/genética , Proteína-Tirosina Quinasas de Adhesión Focal/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Mutación/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Fármacos Sensibilizantes a Radiaciones/metabolismo , Células A549 , Animales , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Línea Celular Tumoral , Daño del ADN/efectos de los fármacos , Femenino , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Ratones , Ratones Desnudos , Mutación/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Interferencia de ARN/efectos de los fármacos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The MYC proto-oncogene is a transcription factor implicated in a broad range of cancers. MYC is regulated by several post-translational modifications including SUMOylation, but the functional impact of this post-translational modification is still unclear. Here, we report that the SUMO E3 ligase PIAS1 SUMOylates MYC. We demonstrate that PIAS1 promotes, in a SUMOylation-dependent manner, MYC phosphorylation at serine 62 and dephosphorylation at threonine 58. These events reduce the MYC turnover, leading to increased transcriptional activity. Furthermore, we find that MYC is SUMOylated in primary B cell lymphomas and that PIAS1 is required for the viability of MYC-dependent B cell lymphoma cells as well as several cancer cell lines of epithelial origin. Finally, Pias1-null mice display endothelial defects reminiscent of Myc-null mice. Taken together, these results indicate that PIAS1 is a positive regulator of MYC.
Asunto(s)
Carcinogénesis/patología , Regulación Neoplásica de la Expresión Génica , Linfoma de Células B/genética , Linfoma de Células B/patología , Proteínas Inhibidoras de STAT Activados/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Regulación hacia Arriba/genética , Animales , Carcinogénesis/genética , Línea Celular , Proliferación Celular , Supervivencia Celular , Semivida , Humanos , Ratones , Fosforilación , Fosfotreonina/metabolismo , Unión Proteica/genética , Proteolisis , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas c-myc/metabolismo , Sumoilación , Transcripción GenéticaRESUMEN
[This corrects the article DOI: 10.1016/j.neo.2016.03.003.].
RESUMEN
KRAS is one of the most commonly mutated oncogenes in human cancer. Mutant KRAS aberrantly regulates metabolic networks. However, the contribution of cellular metabolism to mutant KRAS tumorigenesis is not completely understood. We report that mutant KRAS regulates intracellular fatty acid metabolism through Acyl-coenzyme A (CoA) synthetase long-chain family member 3 (ACSL3), which converts fatty acids into fatty Acyl-CoA esters, the substrates for lipid synthesis and ß-oxidation. ACSL3 suppression is associated with depletion of cellular ATP and causes the death of lung cancer cells. Furthermore, mutant KRAS promotes the cellular uptake, retention, accumulation, and ß-oxidation of fatty acids in lung cancer cells in an ACSL3-dependent manner. Finally, ACSL3 is essential for mutant KRAS lung cancer tumorigenesis in vivo and is highly expressed in human lung cancer. Our data demonstrate that mutant KRAS reprograms lipid homeostasis, establishing a metabolic requirement that could be exploited for therapeutic gain.