RESUMEN
The renal actions of parathyroid hormone (PTH) promote 1,25-vitamin D generation; however, the signaling mechanisms that control PTH-dependent vitamin D activation remain unknown. Here, we demonstrated that salt-inducible kinases (SIKs) orchestrated renal 1,25-vitamin D production downstream of PTH signaling. PTH inhibited SIK cellular activity by cAMP-dependent PKA phosphorylation. Whole-tissue and single-cell transcriptomics demonstrated that both PTH and pharmacologic SIK inhibitors regulated a vitamin D gene module in the proximal tubule. SIK inhibitors increased 1,25-vitamin D production and renal Cyp27b1 mRNA expression in mice and in human embryonic stem cell-derived kidney organoids. Global- and kidney-specific Sik2/Sik3 mutant mice showed Cyp27b1 upregulation, elevated serum 1,25-vitamin D, and PTH-independent hypercalcemia. The SIK substrate CRTC2 showed PTH and SIK inhibitor-inducible binding to key Cyp27b1 regulatory enhancers in the kidney, which were also required for SIK inhibitors to increase Cyp27b1 in vivo. Finally, in a podocyte injury model of chronic kidney disease-mineral bone disorder (CKD-MBD), SIK inhibitor treatment stimulated renal Cyp27b1 expression and 1,25-vitamin D production. Together, these results demonstrated a PTH/SIK/CRTC signaling axis in the kidney that controls Cyp27b1 expression and 1,25-vitamin D synthesis. These findings indicate that SIK inhibitors might be helpful for stimulation of 1,25-vitamin D production in CKD-MBD.
Asunto(s)
Trastorno Mineral y Óseo Asociado a la Enfermedad Renal Crónica , Insuficiencia Renal Crónica , Ratones , Humanos , Animales , Vitamina D/metabolismo , Hormona Paratiroidea/genética , Hormona Paratiroidea/metabolismo , Calcio/metabolismo , 25-Hidroxivitamina D3 1-alfa-Hidroxilasa/metabolismo , Trastorno Mineral y Óseo Asociado a la Enfermedad Renal Crónica/metabolismo , Riñón/metabolismo , Insuficiencia Renal Crónica/metabolismo , Homeostasis , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismoRESUMEN
Multiple cancers regulate oxidative stress by activating the transcription factor NRF2 through mutation of its negative regulator, KEAP1. NRF2 has been studied extensively in KEAP1-mutant cancers; however, the role of this pathway in cancers with wild-type KEAP1 remains poorly understood. To answer this question, we induced NRF2 via pharmacological inactivation of KEAP1 in a panel of 50+ non-small cell lung cancer cell lines. Unexpectedly, marked decreases in viability were observed in >13% of the cell lines-an effect that was rescued by NRF2 ablation. Genome-wide and targeted CRISPR screens revealed that NRF2 induces NADH-reductive stress, through the upregulation of the NAD+-consuming enzyme ALDH3A1. Leveraging these findings, we show that cells treated with KEAP1 inhibitors or those with endogenous KEAP1 mutations are selectively vulnerable to Complex I inhibition, which impairs NADH oxidation capacity and potentiates reductive stress. Thus, we identify reductive stress as a metabolic vulnerability in NRF2-activated lung cancers.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Factor 2 Relacionado con NF-E2 , Humanos , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Línea Celular Tumoral , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Neoplasias Pulmonares/metabolismo , NAD/metabolismo , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismo , Estrés Oxidativo/genética , Transducción de SeñalRESUMEN
To accelerate the translation of cancer nanomedicine, we used an integrated genomic approach to improve our understanding of the cellular processes that govern nanoparticle trafficking. We developed a massively parallel screen that leverages barcoded, pooled cancer cell lines annotated with multiomic data to investigate cell association patterns across a nanoparticle library spanning a range of formulations with clinical potential. We identified both materials properties and cell-intrinsic features that mediate nanoparticle-cell association. Using machine learning algorithms, we constructed genomic nanoparticle trafficking networks and identified nanoparticle-specific biomarkers. We validated one such biomarker: gene expression of SLC46A3, which inversely predicts lipid-based nanoparticle uptake in vitro and in vivo. Our work establishes the power of integrated screens for nanoparticle delivery and enables the identification and utilization of biomarkers to rationally design nanoformulations.
Asunto(s)
Antineoplásicos , Biomarcadores Farmacológicos , Proteínas Transportadoras de Cobre , Composición de Medicamentos , Sistema de Administración de Fármacos con Nanopartículas , Nanopartículas , Neoplasias , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/metabolismo , Línea Celular Tumoral , Proteínas Transportadoras de Cobre/genética , Expresión Génica , Genómica , Humanos , Liposomas , Ratones , Nanomedicina , Nanopartículas/administración & dosificación , Nanopartículas/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Neoplasias/metabolismoRESUMEN
Cutaneous squamous cell carcinoma (cSCC) comprises 15â20% of all skin cancers and has a well-defined progression sequence from precancerous actinic keratosis to invasive cSCC. To identify targets for chemoprevention, we previously reported a cross-species analysis to identify the transcriptional drivers of cSCC development and identified miR-181a as a potential oncomiR. We show that the upregulation of miR-181a promotes multiple protumorigenic properties by targeting an understudied component of TGFß signaling, TGFßR3. miR-181a and TGFßR3 are upregulated and downregulated, respectively, in cSCC. miR-181a overexpression (OE) and TGFßR3 knockdown (KD) significantly suppresses UV-induced apoptosis in HaCaT cells and in primary normal human epidermal keratinocytes. In addition, OE of miR-181a or KD of TGFßR3 by short hairpin RNA enhances anchorage-independent survival. miR-181a OE or TGFßR3 KD enhances cellular migration and invasion and upregulation of epithelialâmesenchymal transition markers. Luciferase reporter assays demonstrate that miR-181a directly targets the 3'-untranslated region of TGFßR3. miR-181a upregulates phosphorylated SMAD3 levels after TGFß2 administration and results in elevated SNAIL and SLUG expression. Finally, we confirm in vivo that miR-181a inhibition compromises tumor growth. Importantly, these phenotypes can be reversed with TGFßR3 OE or KD in the context of miR-181a OE or KD, respectively, further highlighting the physiologic relevance of this regulation in cSCC.
Asunto(s)
Carcinoma de Células Escamosas , MicroARNs , Proteoglicanos , Receptores de Factores de Crecimiento Transformadores beta , Neoplasias Cutáneas , Regiones no Traducidas 3'/genética , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica , Humanos , MicroARNs/genética , Proteoglicanos/genética , Receptores de Factores de Crecimiento Transformadores beta/genética , Neoplasias Cutáneas/patologíaRESUMEN
In a new article in the Journal of Investigative Dermatology, Wang et al. (2021) report that mitochondrial quality control modulates responses to endoplasmic reticulum (ER) stress in melanoma. They implicate a linear pathway of XBP1, MARCH5, and MFN2 that act together to regulate mitochondrial fission and mitophagy and ultimately mediate melanoma cell sensitivity to ER stress. This work informs therapeutic combinations and biomarker strategies for targeting melanoma organellar homeostasis as well as for lifeâdeath decisions.
Asunto(s)
Estrés del Retículo Endoplásmico , Melanoma , Retículo Endoplásmico/metabolismo , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Humanos , Melanoma/metabolismo , Mitocondrias , Proteínas Mitocondriales/metabolismo , MitofagiaRESUMEN
Forward genetic screens across hundreds of cancer cell lines have started to define the genetic dependencies of proliferating human cells and how these vary by genotype and lineage. Most screens, however, have been carried out in culture media that poorly reflect metabolite availability in human blood. Here, we performed CRISPR-based screens in traditional versus human plasma-like medium (HPLM). Sets of conditionally essential genes in human cancer cell lines span several cellular processes and vary with both natural cell-intrinsic diversity and the combination of basal and serum components that comprise typical media. Notably, we traced the causes for each of three conditional CRISPR phenotypes to the availability of metabolites uniquely defined in HPLM versus conventional media. Our findings reveal the profound impact of medium composition on gene essentiality in human cells, and also suggest general strategies for using genetic screens in HPLM to uncover new cancer vulnerabilities and gene-nutrient interactions.
Asunto(s)
Sistemas CRISPR-Cas , Medios de Cultivo , Línea Celular Tumoral , HumanosRESUMEN
In mammalian cells, nutrients and growth factors signal through an array of upstream proteins to regulate the mTORC1 growth control pathway. Because the full complement of these proteins has not been systematically identified, we developed a FACS-based CRISPR-Cas9 genetic screening strategy to pinpoint genes that regulate mTORC1 activity. Along with almost all known positive components of the mTORC1 pathway, we identified many genes that impact mTORC1 activity, including DCAF7, CSNK2B, SRSF2, IRS4, CCDC43, and HSD17B10 Using the genome-wide screening data, we generated a focused sublibrary containing single guide RNAs (sgRNAs) targeting hundreds of genes and carried out epistasis screens in cells lacking nutrient- and stress-responsive mTORC1 modulators, including GATOR1, AMPK, GCN2, and ATF4. From these data, we pinpointed mitochondrial function as a particularly important input into mTORC1 signaling. While it is well appreciated that mitochondria signal to mTORC1, the mechanisms are not completely clear. We find that the kinases AMPK and HRI signal, with varying kinetics, mitochondrial distress to mTORC1, and that HRI acts through the ATF4-dependent up-regulation of both Sestrin2 and Redd1. Loss of both AMPK and HRI is sufficient to render mTORC1 signaling largely resistant to mitochondrial dysfunction induced by the ATP synthase inhibitor oligomycin as well as the electron transport chain inhibitors piericidin and antimycin. Taken together, our data reveal a catalog of genes that impact the mTORC1 pathway and clarify the multifaceted ways in which mTORC1 senses mitochondrial dysfunction.
Asunto(s)
Factor de Transcripción Activador 4/genética , Edición Génica/métodos , Diana Mecanicista del Complejo 1 de la Rapamicina/genética , Mitocondrias/genética , Proteínas Serina-Treonina Quinasas/genética , 3-Hidroxiacil-CoA Deshidrogenasas/genética , 3-Hidroxiacil-CoA Deshidrogenasas/metabolismo , Factor de Transcripción Activador 4/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Aminoácidos/deficiencia , Aminoácidos/farmacología , Antimicina A/análogos & derivados , Antimicina A/farmacología , Proteína 9 Asociada a CRISPR/genética , Proteína 9 Asociada a CRISPR/metabolismo , Sistemas CRISPR-Cas , Medios de Cultivo/química , Medios de Cultivo/farmacología , Regulación de la Expresión Génica , Genoma Humano , Glucosa/deficiencia , Glucosa/farmacología , Células HEK293 , Humanos , Proteínas Sustrato del Receptor de Insulina/genética , Proteínas Sustrato del Receptor de Insulina/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Mitocondrias/patología , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Oligomicinas/farmacología , Proteínas Serina-Treonina Quinasas/metabolismo , ARN Guía de Kinetoplastida/genética , ARN Guía de Kinetoplastida/metabolismo , Factores de Empalme Serina-Arginina/genética , Factores de Empalme Serina-Arginina/metabolismo , Transducción de Señal , eIF-2 Quinasa/genética , eIF-2 Quinasa/metabolismoRESUMEN
The measurement of UV-induced DNA damage as a dosimeter of exposure and predictor of skin cancer risk has been proposed by multiple groups. Although UV-induced mutations and adducts are present in normal-appearing UV-exposed epidermis, sampling normal nonlesional skin requires noninvasive methods to extract epidermal DNA for analysis. Here, we demonstrate the feasibility of such an approach, termed surfactant-based tissue acquisition for molecular profiling. Sampling in patients was performed using a felt-tip pen soaked in a mixture of surfactants (Brij-30/N-decyl-N,N-dimethyl-3-ammonio-1-propanesulfonate). In mice, we show that the epidermis can be selectively removed without scarring, with complete healing within 2 weeks. We exposed hairless mice to low-dose UV radiation over a period of 3 months and serially sampled them through up to 2 months following the cessation of UV exposure, observing a progressive increase in a UV signature mutational burden. To test whether surfactant-based tissue acquisition for molecular profiling could be applied to human patients, samples were collected from sun-exposed and sun-protected areas, which were then subjected to high-depth targeted exome sequencing. Extensive UV-driven mosaicism and substantially increased mutational loads in sun-exposed versus sun-protected areas were observed, suggesting that genomic measures, as an integrated readout of DNA damage, repair, and clonal expansion, may be informative markers of UV exposure.
Asunto(s)
Epidermis/metabolismo , Marcadores Genéticos/genética , Genómica/métodos , Neoplasias Cutáneas/genética , Rayos Ultravioleta/efectos adversos , Animales , Daño del ADN , Epidermis/patología , Epidermis/efectos de la radiación , Humanos , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/patologíaRESUMEN
Dozens of genes contribute to the wide variation in human pigmentation. Many of these genes encode proteins that localize to the melanosome-the organelle, related to the lysosome, that synthesizes pigment-but have unclear functions1,2. Here we describe MelanoIP, a method for rapidly isolating melanosomes and profiling their labile metabolite contents. We use this method to study MFSD12, a transmembrane protein of unknown molecular function that, when suppressed, causes darker pigmentation in mice and humans3,4. We find that MFSD12 is required to maintain normal levels of cystine-the oxidized dimer of cysteine-in melanosomes, and to produce cysteinyldopas, the precursors of pheomelanin synthesis made in melanosomes via cysteine oxidation5,6. Tracing and biochemical analyses show that MFSD12 is necessary for the import of cysteine into melanosomes and, in non-pigmented cells, lysosomes. Indeed, loss of MFSD12 reduced the accumulation of cystine in lysosomes of fibroblasts from patients with cystinosis, a lysosomal-storage disease caused by inactivation of the lysosomal cystine exporter cystinosin7-9. Thus, MFSD12 is an essential component of the cysteine importer for melanosomes and lysosomes.
Asunto(s)
Cisteína/metabolismo , Lisosomas/metabolismo , Melanosomas/metabolismo , Proteínas de la Membrana/metabolismo , Transporte Biológico , Fraccionamiento Celular , Línea Celular , Cistina/metabolismo , Cistinosis/genética , Cistinosis/metabolismo , Fibroblastos , Humanos , Melaninas/metabolismo , Proteínas de la Membrana/deficiencia , Proteínas de la Membrana/genética , Oxidación-ReducciónRESUMEN
In this protocol, pooled sgRNA libraries targeting thousands of genes are computationally designed, generated using microarray-based synthesis techniques, and packaged into lentiviral particles. Target cells of interest are transduced with the lentiviral sgRNA pools to generate a collection of knockout mutants-via Cas9-mediated genomic cleavage-and screened for a phenotype of interest. The relative abundance of each mutant in the population can be monitored over time through high-throughput sequencing of the integrated sgRNA expression cassettes. Using this technique, we outline strategies for the identification of cancer driver genes and genes mediating drug response.
Asunto(s)
Sistemas CRISPR-Cas , Genoma Humano , Estudio de Asociación del Genoma Completo/métodos , Genómica/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Proteínas de Neoplasias/genética , Neoplasias/genética , Técnicas de Inactivación de Genes , Humanos , Proteínas de Neoplasias/antagonistas & inhibidores , Neoplasias/diagnóstico , Fenotipo , Células Tumorales CultivadasRESUMEN
Cutaneous squamous cell carcinoma (cuSCC) comprises 15-20% of all skin cancers, accounting for over 700,000 cases in USA annually. Most cuSCC arise in association with a distinct precancerous lesion, the actinic keratosis (AK). To identify potential targets for molecularly targeted chemoprevention, here we perform integrated cross-species genomic analysis of cuSCC development through the preneoplastic AK stage using matched human samples and a solar ultraviolet radiation-driven Hairless mouse model. We identify the major transcriptional drivers of this progression sequence, showing that the key genomic changes in cuSCC development occur in the normal skin to AK transition. Our data validate the use of this ultraviolet radiation-driven mouse cuSCC model for cross-species analysis and demonstrate that cuSCC bears deep molecular similarities to multiple carcinogen-driven SCCs from diverse sites, suggesting that cuSCC may serve as an effective, accessible model for multiple SCC types and that common treatment and prevention strategies may be feasible.
Asunto(s)
Antineoplásicos/uso terapéutico , Carcinoma de Células Escamosas/genética , Queratosis Actínica/patología , Lesiones Precancerosas/patología , Neoplasias Cutáneas/genética , Animales , Carcinogénesis/genética , Carcinoma de Células Escamosas/etiología , Carcinoma de Células Escamosas/prevención & control , Análisis Mutacional de ADN , Progresión de la Enfermedad , Femenino , Perfilación de la Expresión Génica , Genómica , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Ratones , Ratones Pelados , Terapia Molecular Dirigida/métodos , Lesiones Precancerosas/genética , Análisis de Secuencia de ARN , Piel/patología , Neoplasias Cutáneas/etiología , Neoplasias Cutáneas/prevención & control , Rayos Ultravioleta/efectos adversos , Secuenciación del ExomaAsunto(s)
Antineoplásicos/uso terapéutico , Carcinoma de Células Escamosas/tratamiento farmacológico , Proteínas Quinasas Activadas por Mitógenos/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/uso terapéutico , Neoplasias Cutáneas/tratamiento farmacológico , Animales , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Azetidinas/farmacología , Azetidinas/uso terapéutico , Línea Celular Tumoral , Senescencia Celular/efectos de los fármacos , Humanos , Terapia Molecular Dirigida/métodos , Piperidinas/farmacología , Piperidinas/uso terapéutico , Inhibidores de Proteínas Quinasas/farmacología , Piridonas/farmacología , Piridonas/uso terapéutico , Pirimidinonas/farmacología , Pirimidinonas/uso terapéutico , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
BRAF inhibitor (BRAFi) therapy is associated with the induction of neoplasia, most commonly cutaneous squamous cell carcinoma (cuSCC). This toxicity is explained in part by "paradoxical ERK activation," or the hyperactivation of ERK signaling by BRAFi in BRAF wild-type cells. However, the rate of cuSCC induction varies widely among BRAFi. To explore this mechanistically, we profiled paradoxical ERK activation by vemurafenib, dabrafenib, encorafenib (LGX818), and PLX8394, demonstrating that vemurafenib induces ERK activation the greatest, while dabrafenib and encorafenib have higher "paradox indices", defined as the pERK activation EC80 divided by the IC80 against A375, corresponding to wider therapeutic windows for achieving tumor inhibition without paradoxical ERK activation. Our results identify differences in the paradox indices of these compounds as a potential mechanism for the differences in cuSCC induction rates and highlight the utility of using ERK activity as a biomarker for maximizing the clinical utility of BRAFi.
Asunto(s)
Carcinoma de Células Escamosas/inducido químicamente , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Inhibidores de Proteínas Quinasas/efectos adversos , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Neoplasias Cutáneas/inducido químicamente , Apoptosis/efectos de los fármacos , Carbamatos/efectos adversos , Línea Celular , Línea Celular Tumoral , Activación Enzimática/efectos de los fármacos , Compuestos Heterocíclicos con 2 Anillos/efectos adversos , Humanos , Imidazoles/efectos adversos , Indoles/efectos adversos , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Oximas/efectos adversos , Sulfonamidas/efectos adversos , VemurafenibRESUMEN
Protein kinases are mutated or otherwise rendered constitutively active in numerous cancers where they are attractive therapeutic targets with well over a dozen kinase inhibitors now being used in therapy. While fluorescent sensors have capacity to measure changes in kinase activity, surprisingly they have not been utilized for biomarker studies. A first-generation peptide sensor for ERK based on the Sox fluorophore is described. This sensor called ERK-sensor-D1 possesses high activity toward ERK and more than 10-fold discrimination over other MAPKs. The sensor can rapidly quantify ERK activity in cell lysates and monitor ERK pathway engagement by BRAF and MEK inhibitors in cultured melanoma cell lines. The dynamic range of the sensor assay allows ERK activities that have potential for profound clinical consequences to be rapidly distinguished.
RESUMEN
Sorafenib is U.S. Food and Drug Adminstration-approved for the treatment of renal cell carcinoma and hepatocellular carcinoma and has been combined with numerous other targeted therapies and chemotherapies in the treatment of many cancers. Unfortunately, as with other RAF inhibitors, patients treated with sorafenib have a 5% to 10% rate of developing cutaneous squamous cell carcinoma (cSCC)/keratoacanthomas. Paradoxical activation of extracellular signal-regulated kinase (ERK) in BRAF wild-type cells has been implicated in RAF inhibitor-induced cSCC. Here, we report that sorafenib suppresses UV-induced apoptosis specifically by inhibiting c-jun-NH(2)-kinase (JNK) activation through the off-target inhibition of leucine zipper and sterile alpha motif-containing kinase (ZAK). Our results implicate suppression of JNK signaling, independent of the ERK pathway, as an additional mechanism of adverse effects of sorafenib. This has broad implications for combination therapies using sorafenib with other modalities that induce apoptosis.
Asunto(s)
Carcinoma de Células Escamosas/tratamiento farmacológico , Niacinamida/análogos & derivados , Compuestos de Fenilurea/efectos adversos , Proteínas Quinasas/metabolismo , Neoplasias Cutáneas/tratamiento farmacológico , Antineoplásicos/administración & dosificación , Antineoplásicos/efectos adversos , Apoptosis/efectos de los fármacos , Carcinoma de Células Escamosas/inducido químicamente , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Humanos , MAP Quinasa Quinasa 4/metabolismo , Quinasas Quinasa Quinasa PAM , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Niacinamida/administración & dosificación , Niacinamida/efectos adversos , Compuestos de Fenilurea/administración & dosificación , Proteínas Quinasas/genética , Neoplasias Cutáneas/inducido químicamente , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Sorafenib , Quinasas raf/genética , Quinasas raf/metabolismoRESUMEN
Vemurafenib and dabrafenib selectively inhibit the v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) kinase, resulting in high response rates and increased survival in melanoma. Approximately 22% of individuals treated with vemurafenib develop cutaneous squamous cell carcinoma (cSCC) during therapy. The prevailing explanation for this is drug-induced paradoxical ERK activation, resulting in hyperproliferation. Here we show an unexpected and novel effect of vemurafenib/PLX4720 in suppressing apoptosis through the inhibition of multiple off-target kinases upstream of c-Jun N-terminal kinase (JNK), principally ZAK. JNK signaling is suppressed in multiple contexts, including in cSCC of vemurafenib-treated patients, as well as in mice. Expression of a mutant ZAK that cannot be inhibited reverses the suppression of JNK activation and apoptosis. Our results implicate suppression of JNK-dependent apoptosis as a significant, independent mechanism that cooperates with paradoxical ERK activation to induce cSCC, suggesting broad implications for understanding toxicities associated with BRAF inhibitors and for their use in combination therapies. DOI: http://dx.doi.org/10.7554/eLife.00969.001.