RESUMEN
Discoveries of the roles of RAS oncogenes in cancer development four decades ago opened the door to proving that tumor development is driven by somatic mutations' altering the genomes of cancer cells. These discoveries led to illusions about the simplicity of cancer pathogenesis and how cancer could be cured.
Asunto(s)
Genes ras , Neoplasias , Humanos , Neoplasias/genética , Neoplasias/terapia , Oncogenes , MutaciónRESUMEN
Tumor evolution is driven by the progressive acquisition of genetic and epigenetic alterations that enable uncontrolled growth and expansion to neighboring and distal tissues. The study of phylogenetic relationships between cancer cells provides key insights into these processes. Here, we introduced an evolving lineage-tracing system with a single-cell RNA-seq readout into a mouse model of Kras;Trp53(KP)-driven lung adenocarcinoma and tracked tumor evolution from single-transformed cells to metastatic tumors at unprecedented resolution. We found that the loss of the initial, stable alveolar-type2-like state was accompanied by a transient increase in plasticity. This was followed by the adoption of distinct transcriptional programs that enable rapid expansion and, ultimately, clonal sweep of stable subclones capable of metastasizing. Finally, tumors develop through stereotypical evolutionary trajectories, and perturbing additional tumor suppressors accelerates progression by creating novel trajectories. Our study elucidates the hierarchical nature of tumor evolution and, more broadly, enables in-depth studies of tumor progression.
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Neoplasias , Animales , Genes ras , Ratones , Neoplasias/genética , Filogenia , Secuenciación del ExomaRESUMEN
STK19 was proposed to be a cancer driver, and recent work by Yin et al. (2019) in Cell suggested that the frequently recurring STK19 D89N substitution represents a gain-of-function change, allowing increased phosphorylation of NRAS to enhance melanocyte transformation. Here we show that the STK19 gene has been incorrectly annotated, and that the expressed protein is 110 amino acids shorter than indicated by current databases. The "cancer driving" STK19 D89N substitution is thus outside the coding region. We also fail to detect evidence of the mutation affecting STK19 expression; instead, it is a UV signature mutation, found in the promoter of other genes as well. Furthermore, STK19 is exclusively nuclear and chromatin-associated, while no evidence for it being a kinase was found. The data in this Matters Arising article raise fundamental questions about the recently proposed role for STK19 in melanoma progression via a function as an NRAS kinase, suggested by Yin et al. (2019) in Cell. See also the response by Yin et al. (2020), published in this issue.
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Melanoma , Recurrencia Local de Neoplasia , GTP Fosfohidrolasas/metabolismo , Genes ras , Humanos , Melanoma/genética , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Mutación , Proteínas Nucleares , Fosforilación , Proteínas Serina-Treonina Quinasas/genética , Transducción de SeñalRESUMEN
KRAS mutant pancreatic ductal adenocarcinoma (PDAC) is characterized by a desmoplastic response that promotes hypovascularity, immunosuppression, and resistance to chemo- and immunotherapies. We show that a combination of MEK and CDK4/6 inhibitors that target KRAS-directed oncogenic signaling can suppress PDAC proliferation through induction of retinoblastoma (RB) protein-mediated senescence. In preclinical mouse models of PDAC, this senescence-inducing therapy produces a senescence-associated secretory phenotype (SASP) that includes pro-angiogenic factors that promote tumor vascularization, which in turn enhances drug delivery and efficacy of cytotoxic gemcitabine chemotherapy. In addition, SASP-mediated endothelial cell activation stimulates the accumulation of CD8+ T cells into otherwise immunologically "cold" tumors, sensitizing tumors to PD-1 checkpoint blockade. Therefore, in PDAC models, therapy-induced senescence can establish emergent susceptibilities to otherwise ineffective chemo- and immunotherapies through SASP-dependent effects on the tumor vasculature and immune system.
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Envejecimiento/fisiología , Carcinoma Ductal Pancreático/patología , Remodelación Vascular/fisiología , Animales , Linfocitos T CD8-positivos/inmunología , Carcinoma Ductal Pancreático/microbiología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Quinasa 4 Dependiente de la Ciclina/metabolismo , Quinasa 6 Dependiente de la Ciclina/metabolismo , Regulación Neoplásica de la Expresión Génica/genética , Genes ras/genética , Humanos , Inmunoterapia/métodos , Sistema de Señalización de MAP Quinasas/fisiología , Ratones , Neoplasias Pancreáticas/patología , Proteína de Retinoblastoma/inmunología , Transducción de Señal/genética , Microambiente Tumoral , Remodelación Vascular/genéticaRESUMEN
Targeting of the RAS pathway has long been a critical therapeutic challenge in oncology. Burgess et al. examine how the relative expression of mutant and wild-type KRAS modulates clonal fitness and sensitivity to MEK inhibitors in a model of KrasG12D mutant acute myeloid leukemia and propose its use as a predictive biomarker.
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Mutación/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Genes ras/efectos de los fármacos , Humanos , Leucemia Mieloide Aguda , Proteínas ras/genéticaRESUMEN
Chromatin remodeling proteins are frequently dysregulated in human cancer, yet little is known about how they control tumorigenesis. Here, we uncover an epigenetic program mediated by the NAD(+)-dependent histone deacetylase Sirtuin 6 (SIRT6) that is critical for suppression of pancreatic ductal adenocarcinoma (PDAC), one of the most lethal malignancies. SIRT6 inactivation accelerates PDAC progression and metastasis via upregulation of Lin28b, a negative regulator of the let-7 microRNA. SIRT6 loss results in histone hyperacetylation at the Lin28b promoter, Myc recruitment, and pronounced induction of Lin28b and downstream let-7 target genes, HMGA2, IGF2BP1, and IGF2BP3. This epigenetic program defines a distinct subset with a poor prognosis, representing 30%-40% of human PDAC, characterized by reduced SIRT6 expression and an exquisite dependence on Lin28b for tumor growth. Thus, we identify SIRT6 as an important PDAC tumor suppressor and uncover the Lin28b pathway as a potential therapeutic target in a molecularly defined PDAC subset. PAPERCLIP.
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Adenocarcinoma/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias Pancreáticas/genética , Proteínas de Unión al ARN/genética , Sirtuinas/genética , Acetilación , Animales , Línea Celular Tumoral , Ensamble y Desensamble de Cromatina , Epigénesis Genética , Femenino , Genes ras , Histonas/metabolismo , Humanos , Masculino , Ratones , Ratones Noqueados , Proteínas de Unión al ARN/metabolismo , Proteínas Supresoras de Tumor/metabolismoRESUMEN
In this issue of Molecular Cell, Shui et al.1 use a systems biology approach to unravel a paradoxical role of microRNA in oncogenic KrasG12D regulation of gene and protein expression.
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MicroARNs , MicroARNs/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Genes ras , MutaciónRESUMEN
K-Ras frequently acquires gain-of-function mutations (K-RasG12D being the most common) that trigger significant transcriptomic and proteomic changes to drive tumorigenesis. Nevertheless, oncogenic K-Ras-induced dysregulation of post-transcriptional regulators such as microRNAs (miRNAs) during oncogenesis is poorly understood. Here, we report that K-RasG12D promotes global suppression of miRNA activity, resulting in the upregulation of hundreds of targets. We constructed a comprehensive profile of physiological miRNA targets in mouse colonic epithelium and tumors expressing K-RasG12D using Halo-enhanced Argonaute pull-down. Combining this with parallel datasets of chromatin accessibility, transcriptome, and proteome, we uncovered that K-RasG12D suppressed the expression of Csnk1a1 and Csnk2a1, subsequently decreasing Ago2 phosphorylation at Ser825/829/832/835. Hypo-phosphorylated Ago2 increased binding to mRNAs while reducing its activity to repress miRNA targets. Our findings connect a potent regulatory mechanism of global miRNA activity to K-Ras in a pathophysiological context and provide a mechanistic link between oncogenic K-Ras and the post-transcriptional upregulation of miRNA targets.
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MicroARNs , Neoplasias , Animales , Ratones , Carcinogénesis/genética , Transformación Celular Neoplásica/genética , Genes ras , MicroARNs/genética , MicroARNs/metabolismo , Neoplasias/genética , ProteómicaRESUMEN
K-Ras and H-Ras share identical effectors and have similar properties; however, the high degree of tumor-type specificity associated with K-Ras and H-Ras mutations suggests that they have unique roles in oncogenesis. Here, we report that oncogenic K-Ras, but not H-Ras, suppresses non-canonical Wnt/Ca(2+) signaling, an effect that contributes strongly to its tumorigenic properties. K-Ras does this by binding to calmodulin and so reducing CaMKii activity and expression of Fzd8. Restoring Fzd8 in K-Ras mutant pancreatic cells suppresses malignancy, whereas depletion of Fzd8 in H-Ras(V12)-transformed cells enhances their tumor initiating capacity. Interrupting K-Ras-calmodulin binding using genetic means or by treatment with an orally active protein kinase C (PKC)-activator, prostratin, represses tumorigenesis in K-Ras mutant pancreatic cancer cells. These findings provide an alternative way to selectively target this "undruggable" protein.
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Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Receptores de Superficie Celular/metabolismo , Vía de Señalización Wnt , Secuencia de Aminoácidos , Animales , Animales Modificados Genéticamente , Calmodulina/metabolismo , Línea Celular Tumoral , Modelos Animales de Enfermedad , Femenino , Genes ras , Humanos , Ratones , Datos de Secuencia Molecular , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/metabolismo , Papiloma/metabolismo , Ésteres del Forbol/administración & dosificación , Fosforilación , Unión Proteica/efectos de los fármacosRESUMEN
Healthy skin is a mosaic of wild-type and mutant clones1,2. Although injury can cooperate with mutated Ras family proteins to promote tumorigenesis3-12, the consequences in genetically mosaic skin are unknown. Here we show that after injury, wild-type cells suppress aberrant growth induced by oncogenic Ras. HrasG12V/+ and KrasG12D/+ cells outcompete wild-type cells in uninjured, mosaic tissue but their expansion is prevented after injury owing to an increase in the fraction of proliferating wild-type cells. Mechanistically, we show that, unlike HrasG12V/+ cells, wild-type cells respond to autocrine and paracrine secretion of EGFR ligands, and this differential activation of the EGFR pathway explains the competitive switch during injury repair. Inhibition of EGFR signalling via drug or genetic approaches diminishes the proportion of dividing wild-type cells after injury, leading to the expansion of HrasG12V/+ cells. Increased proliferation of wild-type cells via constitutive loss of the cell cycle inhibitor p21 counteracts the expansion of HrasG12V/+ cells even in the absence of injury. Thus, injury has a role in switching the competitive balance between oncogenic and wild-type cells in genetically mosaic skin.
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Proliferación Celular , Genes ras , Mosaicismo , Mutación , Piel , Proteínas ras , Ciclo Celular , Proliferación Celular/genética , Receptores ErbB/metabolismo , Proteínas ras/genética , Proteínas ras/metabolismo , Piel/citología , Piel/lesiones , Piel/metabolismo , Piel/patología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/deficiencia , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismoRESUMEN
Context-specific molecular vulnerabilities that arise during tumor evolution represent an attractive intervention target class. However, the frequency and diversity of somatic lesions detected among lung tumors can confound efforts to identify these targets. To confront this challenge, we have applied parallel screening of chemical and genetic perturbations within a panel of molecularly annotated NSCLC lines to identify intervention opportunities tightly linked to molecular response indicators predictive of target sensitivity. Anchoring this analysis on a matched tumor/normal cell model from a lung adenocarcinoma patient identified three distinct target/response-indicator pairings that are represented with significant frequencies (6%-16%) in the patient population. These include NLRP3 mutation/inflammasome activation-dependent FLIP addiction, co-occurring KRAS and LKB1 mutation-driven COPI addiction, and selective sensitivity to a synthetic indolotriazine that is specified by a seven-gene expression signature. Target efficacies were validated in vivo, and mechanism-of-action studies informed generalizable principles underpinning cancer cell biology.
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Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Ensayos de Selección de Medicamentos Antitumorales , Indoles/farmacología , Neoplasias Pulmonares/metabolismo , Triazinas/farmacología , Animales , Proteína Reguladora de Apoptosis Similar a CASP8 y FADD/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Proteínas Portadoras , Línea Celular Tumoral , Proteína Coatómero/metabolismo , Femenino , Genes ras , Xenoinjertos , Humanos , Neoplasias Pulmonares/patología , Lisosomas/metabolismo , Ratones , Terapia Molecular Dirigida , Proteína con Dominio Pirina 3 de la Familia NLR , Trasplante de Neoplasias , Fosforilación OxidativaRESUMEN
Squamous cell carcinomas are triggered by marked elevation of RAS-MAPK signalling and progression from benign papilloma to invasive malignancy1-4. At tumour-stromal interfaces, a subset of tumour-initiating progenitors, the cancer stem cells, obtain increased resistance to chemotherapy and immunotherapy along this pathway5,6. The distribution and changes in cancer stem cells during progression from a benign state to invasive squamous cell carcinoma remain unclear. Here we show in mice that, after oncogenic RAS activation, cancer stem cells rewire their gene expression program and trigger self-propelling, aberrant signalling crosstalk with their tissue microenvironment that drives their malignant progression. The non-genetic, dynamic cascade of intercellular exchanges involves downstream pathways that are often mutated in advanced metastatic squamous cell carcinomas with high mutational burden7. Coupling our clonal skin HRASG12V mouse model with single-cell transcriptomics, chromatin landscaping, lentiviral reporters and lineage tracing, we show that aberrant crosstalk between cancer stem cells and their microenvironment triggers angiogenesis and TGFß signalling, creating conditions that are conducive for hijacking leptin and leptin receptor signalling, which in turn launches downstream phosphoinositide 3-kinase (PI3K)-AKT-mTOR signalling during the benign-to-malignant transition. By functionally examining each step in this pathway, we reveal how dynamic temporal crosstalk with the microenvironment orchestrated by the stem cells profoundly fuels this path to malignancy. These insights suggest broad implications for cancer therapeutics.
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Carcinoma de Células Escamosas , Genes ras , Células Madre Neoplásicas , Transducción de Señal , Microambiente Tumoral , Proteínas ras , Animales , Ratones , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Leptina/metabolismo , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Neovascularización Patológica , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas ras/genética , Proteínas ras/metabolismo , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
Oncogenic RAS signaling reprograms gene expression through both transcriptional and post-transcriptional mechanisms. While transcriptional regulation downstream of RAS is relatively well characterized, how RAS post-transcriptionally modulates gene expression to promote malignancy remains largely unclear. Using quantitative RNA interactome capture analysis, we here reveal that oncogenic RAS signaling reshapes the RNA-bound proteomic landscape of pancreatic cancer cells, with a network of nuclear proteins centered around nucleolin displaying enhanced RNA-binding activity. We show that nucleolin is phosphorylated downstream of RAS, which increases its binding to pre-ribosomal RNA (rRNA), boosts rRNA production, and promotes ribosome biogenesis. This nucleolin-dependent enhancement of ribosome biogenesis is crucial for RAS-induced pancreatic cancer cell proliferation and can be targeted therapeutically to inhibit tumor growth. Our results reveal that oncogenic RAS signaling drives ribosome biogenesis by regulating the RNA-binding activity of nucleolin and highlight a crucial role for this mechanism in RAS-mediated tumorigenesis.
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Genes ras , Neoplasias Pancreáticas , Humanos , Sistema de Señalización de MAP Quinasas , Proteómica , Fosfoproteínas/metabolismo , ARN Ribosómico/metabolismo , ARN/metabolismo , Transformación Celular Neoplásica/genética , Ribosomas/genética , Ribosomas/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , NucleolinaRESUMEN
In this issue of Molecular Cell, Terrell et al. (2019) characterize the interactions of RAS-RAF complexes in live cells. Using bioluminescence resonance energy transfer (BRET) technology, they show that individual RAF family members exhibit distinct binding affinities to each RAS family protein, with CRAF exhibiting high binding affinities for all RAS proteins and BRAF exhibiting increased binding affinity for KRAS.
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Genes ras , Proteínas Proto-Oncogénicas B-raf/genética , Carcinogénesis , Crimen , Humanos , Proteínas rasRESUMEN
Super-enhancers are large clusters of enhancers that activate gene expression. Broad trimethyl histone H3 lysine 4 (H3K4me3) often defines active tumor suppressor genes. However, how these epigenomic signatures are regulated for tumor suppression is little understood. Here we show that brain-specific knockout of the H3K4 methyltransferase MLL4 (a COMPASS-like enzyme, also known as KMT2D) in mice spontaneously induces medulloblastoma. Mll4 loss upregulates oncogenic Ras and Notch pathways while downregulating neuronal gene expression programs. MLL4 enhances DNMT3A-catalyzed DNA methylation and SIRT1/BCL6-mediated H4K16 deacetylation, which antagonize expression of Ras activators and Notch pathway components, respectively. Notably, Mll4 loss downregulates tumor suppressor genes (e.g., Dnmt3a and Bcl6) by diminishing broad H3K4me3 and super-enhancers and also causes widespread impairment of these epigenomic signatures during medulloblastoma genesis. These findings suggest an anti-tumor role for super-enhancers and provide a unique tumor-suppressive mechanism in which MLL4 is necessary to maintain broad H3K4me3 and super-enhancers at tumor suppressor genes.
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Neoplasias Cerebelosas/genética , Metilación de ADN , Genes Supresores de Tumor , N-Metiltransferasa de Histona-Lisina/genética , Meduloblastoma/genética , Oncogenes , Procesamiento Proteico-Postraduccional , Acetilación , Animales , Proliferación Celular , Neoplasias Cerebelosas/metabolismo , Neoplasias Cerebelosas/patología , ADN (Citosina-5-)-Metiltransferasas/genética , ADN (Citosina-5-)-Metiltransferasas/metabolismo , ADN Metiltransferasa 3A , Regulación Neoplásica de la Expresión Génica , Genes ras , N-Metiltransferasa de Histona-Lisina/deficiencia , Lisina , Meduloblastoma/metabolismo , Meduloblastoma/patología , Ratones Noqueados , Proteínas Proto-Oncogénicas c-bcl-6/genética , Proteínas Proto-Oncogénicas c-bcl-6/metabolismo , Receptores Notch/genética , Receptores Notch/metabolismo , Transducción de Señal , Sirtuina 1/genética , Sirtuina 1/metabolismoRESUMEN
The process of oncogene-induced senescence (OIS) and the conversion between OIS and malignant transformation during carcinogenesis is poorly understood. Here, we show that following overactivation of oncogene Ras in lung epithelial cells, high-level transforming growth factor ß1 (TGF-ß1)-activated SMAD3, but not SMAD2 or SMAD4, plays a determinant role in inducing cellular senescence independent of the p53/p16/p15 senescence pathways. Importantly, SMAD3 binds a potential tumor suppressor ATOH8 to form a transcriptional complex that directly represses a series of cell cycle-promoting genes and consequently causes senescence in lung epithelial cells. Interestingly, the prosenescent SMAD3 converts to being oncogenic and essentially facilitates oncogenic Ras-driven malignant transformation. Furthermore, depleting Atoh8 rapidly accelerates oncogenic Ras-driven lung tumorigenesis, and lung cancers driven by mutant Ras and Atoh8 loss, but not by mutant Ras only, are sensitive to treatment of a specific SMAD3 inhibitor. Moreover, hypermethylation of the ATOH8 gene can be found in approximately 12% of clinical lung cancer cases. Together, our findings demonstrate not only epithelial cellular senescence directed by a potential tumor suppressor-controlled transcriptional program but also an important interplay between the prosenescent and transforming effects of TGF-ß/SMAD3, potentially laying a foundation for developing early detection and anticancer strategies.
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Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Transformación Celular Neoplásica , Genes ras , Proteína smad3 , Humanos , Transformación Celular Neoplásica/genética , Senescencia Celular/genética , Genes Supresores de Tumor , Proteína smad3/genética , Proteína smad3/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismoRESUMEN
The NF-κB family of transcription factors and the Ras family of small GTPases are important mediators of proproliferative signaling that drives tumorigenesis and carcinogenesis. The κB-Ras proteins were previously shown to inhibit both NF-κB and Ras activation through independent mechanisms, implicating them as tumor suppressors with potentially broad relevance to human cancers. In this study, we have used two mouse models to establish the relevance of the κB-Ras proteins for tumorigenesis. Additionally, we have utilized a pan-cancer bioinformatics analysis to explore the role of the κB-Ras proteins in human cancers. Surprisingly, we find that the genes encoding κB-Ras 1 (NKIRAS1) and κB-Ras 2 (NKIRAS2) are rarely down-regulated in tumor samples with oncogenic Ras mutations. Reduced expression of human NKIRAS1 alone is associated with worse prognosis in at least four cancer types and linked to a network of genes implicated in tumorigenesis. Our findings provide direct evidence that loss of NKIRAS1 in human tumors that do not carry oncogenic RAS mutations is associated with worse clinical outcomes.
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Carcinogénesis , Proteínas Portadoras , Genes Supresores de Tumor , Animales , Humanos , Ratones , Carcinogénesis/genética , Transformación Celular Neoplásica/genética , Genes ras , FN-kappa B/metabolismo , Proteínas ras/metabolismo , Proteínas Portadoras/genéticaRESUMEN
MEK inhibition in combination with a glycogen synthase kinase-3ß (GSK3ß) inhibitor, referred as the 2i condition, favors pluripotency in embryonic stem cells (ESCs). However, the mechanisms by which the 2i condition limits ESC differentiation and whether RAS proteins are involved in this phenomenon remain poorly understood. Here we show that RAS nullyzygosity reduces the growth of mouse ESCs (mESCs) and prohibits their differentiation. Upon RAS deficiency or MEK inhibition, ERF (E twenty-six 2 [Ets2]-repressive factor), a transcriptional repressor from the ETS domain family, translocates to the nucleus, where it binds to the enhancers of pluripotency factors and key RAS targets. Remarkably, deletion of Erf rescues the proliferative defects of RAS-devoid mESCs and restores their capacity to differentiate. Furthermore, we show that Erf loss enables the development of RAS nullyzygous teratomas. In summary, this work reveals an essential role for RAS proteins in pluripotency and identifies ERF as a key mediator of the response to RAS/MEK/ERK inhibition in mESCs.
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Células Madre Embrionarias/citología , Genes ras , Proteínas Represoras/fisiología , Animales , Diferenciación Celular , Línea Celular , Células Madre Embrionarias/metabolismo , Elementos de Facilitación Genéticos , Eliminación de Gen , Ratones , Ratones Desnudos , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Teratoma/genéticaRESUMEN
Nutrition exerts considerable effects on health, and dietary interventions are commonly used to treat diseases of metabolic aetiology. Although cancer has a substantial metabolic component1, the principles that define whether nutrition may be used to influence outcomes of cancer are unclear2. Nevertheless, it is established that targeting metabolic pathways with pharmacological agents or radiation can sometimes lead to controlled therapeutic outcomes. By contrast, whether specific dietary interventions can influence the metabolic pathways that are targeted in standard cancer therapies is not known. Here we show that dietary restriction of the essential amino acid methionine-the reduction of which has anti-ageing and anti-obesogenic properties-influences cancer outcome, through controlled and reproducible changes to one-carbon metabolism. This pathway metabolizes methionine and is the target of a variety of cancer interventions that involve chemotherapy and radiation. Methionine restriction produced therapeutic responses in two patient-derived xenograft models of chemotherapy-resistant RAS-driven colorectal cancer, and in a mouse model of autochthonous soft-tissue sarcoma driven by a G12D mutation in KRAS and knockout of p53 (KrasG12D/+;Trp53-/-) that is resistant to radiation. Metabolomics revealed that the therapeutic mechanisms operate via tumour-cell-autonomous effects on flux through one-carbon metabolism that affects redox and nucleotide metabolism-and thus interact with the antimetabolite or radiation intervention. In a controlled and tolerated feeding study in humans, methionine restriction resulted in effects on systemic metabolism that were similar to those obtained in mice. These findings provide evidence that a targeted dietary manipulation can specifically affect tumour-cell metabolism to mediate broad aspects of cancer outcome.
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Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/metabolismo , Modelos Animales de Enfermedad , Metabolómica , Metionina/administración & dosificación , Metionina/farmacología , Sarcoma/tratamiento farmacológico , Neoplasias de los Tejidos Blandos/tratamiento farmacológico , Animales , Línea Celular Tumoral , Neoplasias Colorrectales/genética , Dieta , Femenino , Fluorouracilo/farmacología , Fluorouracilo/uso terapéutico , Genes p53 , Genes ras , Voluntarios Sanos , Humanos , Masculino , Metionina/metabolismo , Ratones , Persona de Mediana Edad , Mutación , Prueba de Estudio Conceptual , Sarcoma/genética , Sarcoma/metabolismo , Neoplasias de los Tejidos Blandos/genética , Neoplasias de los Tejidos Blandos/metabolismo , Azufre/metabolismo , Resultado del TratamientoRESUMEN
RAS mutants are major therapeutic targets in oncology with few efficacious direct inhibitors available. The identification of a shallow pocket near the Switch II region on RAS has led to the development of small-molecule drugs that target this site and inhibit KRAS(G12C) and KRAS(G12D). To discover other regions on RAS that may be targeted for inhibition, we have employed small synthetic binding proteins termed monobodies that have a strong propensity to bind to functional sites on a target protein. Here, we report a pan-RAS monobody, termed JAM20, that bound to all RAS isoforms with nanomolar affinity and demonstrated limited nucleotide-state specificity. Upon intracellular expression, JAM20 potently inhibited signaling mediated by all RAS isoforms and reduced oncogenic RAS-mediated tumorigenesis in vivo. NMR and mutation analysis determined that JAM20 bound to a pocket between Switch I and II, which is similarly targeted by low-affinity, small-molecule inhibitors, such as BI-2852, whose in vivo efficacy has not been demonstrated. Furthermore, JAM20 directly competed with both the RAF(RBD) and BI-2852. These results provide direct validation of targeting the Switch I/II pocket for inhibiting RAS-driven tumorigenesis. More generally, these results demonstrate the utility of tool biologics as probes for discovering and validating druggable sites on challenging targets.