Metabolic Rewiring by Oncogenic BRAF V600E Links Ketogenesis Pathway to BRAF-MEK1 Signaling

Ketone Body Acetoacetate Buffers Methylglyoxal via a Non-enzymatic Conversion during Diabetic and Dietary Ketosis

The α-oxoaldehyde methylglyoxal is a ubiquitous and highly reactive metabolite known to be involved in aging- and diabetes-related diseases. If not detoxified by the endogenous glyoxalase system, it exerts its detrimental effects primarily by reacting with biopolymers such as DNA and proteins. We now demonstrate that during ketosis, another metabolic route is operative via direct non-enzymatic aldol reaction between methylglyoxal and the ketone body acetoacetate, leading to 3-hydroxyhexane-2,5-dione. This novel metabolite is present at a concentration of 10%-20% of the methylglyoxal level in the blood of insulin-starved patients. By employing a metabolite-alkyne-tagging strategy it is clarified that 3-hydroxyhexane-2,5-dione is further metabolized to non-glycating species in human blood. The discovery represents a new direction within non-enzymatic metabolism and within the use of alkyne-tagging for metabolism studies and it revitalizes acetoacetate as a competent endogenous carbon nucleophile.

BRAF inhibitors: resistance and the promise of combination treatments for melanoma

Identification of mutations in the gene encoding the serine/threonine-protein kinase, BRAF, and constitutive activation of the mitogen-activated protein kinase (MAPK) pathway in around 50% of malignant melanomas have led to the development and regulatory approval of targeted pathway inhibitor drugs. A proportion of patients are intrinsically resistant to BRAF inhibitors, and most patients who initially respond, acquire resistance within months. In this review, we discuss pathway inhibitors and their mechanisms of resistance, and we focus on numerous efforts to improve clinical benefits through combining agents with disparate modes of action, including combinations with checkpoint inhibitor antibodies. We discuss the merits of combination strategies based on enhancing immune responses or overcoming tumor-associated immune escape mechanisms. Emerging insights into mechanisms of action, resistance pathways and their impact on host-tumor relationships will inform the design of optimal combinations therapies to improve outcomes for patients who currently do not benefit from recent treatment breakthroughs.

Inactivation of HMGCL promotes proliferation and metastasis of nasopharyngeal carcinoma by suppressing oxidative stress

Altered metabolism is considered as a hallmark of cancer. Here we investigated expression of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) 2 lyase (HMGCL), an essential enzyme in ketogenesis, which produces ketone bodies by the breakdown of fatty acids to supply energy, in nasopharyngeal carcinoma (NPC). The expression of HMGCL was silenced in NPC tissue. Downregulation of HMGCL in NPC was associated with low intracellular β-hydroxybutyrate (β-HB) production, thereby reducing reactive oxygen species (ROS) generation. Ectopic expression of HMGCL restored β-HB level, associated with suppressed proliferation and colony formation of NPC cells in vitro and decreased tumorigenicity in vivo. HMGCL suppressed the migration and invasion of NPC cells in vitro via mesenchymal-epithelial transition. Furthermore, extracellular β-HB supply suppressed the proliferation and migration of NPC cells. Both intra- and extracellular β-HB exerting a suppressive role in NPC depends on ROS generation. Ketogenesis may be impaired in NPC cells due to lack of HMGCL expression, suggesting that it may be a promising target in NPC therapy.

Toxicogenomic and bioinformatics platforms to identify key molecular mechanisms of a curcumin-analogue DM-1 toxicity in melanoma cells

Melanoma is a highly invasive and metastatic cancer with high mortality rates and chemoresistance. Around 50% of melanomas are driven by activating mutations in BRAF that has led to the development of potent anti-BRAF inhibitors. However resistance to anti-BRAF therapy usually develops within a few months and consequently there is a need to identify alternative therapies that will bypass BRAF inhibitor resistance. The curcumin analogue DM-1 (sodium 4-[5-(4-hydroxy-3-methoxy-phenyl)-3-oxo-penta-1,4-dienyl]-2-methoxy-phenolate) has substantial anti-tumor activity in melanoma, but its mechanism of action remains unclear. Here we use a synthetic lethal genetic screen in Saccharomyces cerevisiae to identify 211 genes implicated in sensitivity to DM-1 toxicity. From these 211 genes, 74 had close human orthologues implicated in oxidative phosphorylation, insulin signaling and iron and RNA metabolism. Further analysis identified 7 target genes (ADK, ATP6V0B, PEMT, TOP1, ZFP36, ZFP36L1, ZFP36L2) with differential expression during melanoma progression implicated in regulation of tumor progression, cell differentiation, and epithelial-mesenchymal transition. Of these TOP1 and ADK were regulated by DM-1 in treatment-naïve and vemurafenib-resistant melanoma cells respectively. These data reveal that the anticancer effect of curcumin analogues is likely to be mediated via multiple targets and identify several genes that represent candidates for combinatorial targeting in melanoma.

Looking to the metabolic landscapes for prostate health monitoring

Abnormal metabolism is a widely accepted biological signature of prostatic diseases, including prostate cancer and benign prostate hyperplasia. Recently accumulated epidemiological and experimental evidence illustrate that the metabolic syndrome, impaired mitochondrial function, and prostatic pathological conditions intersect. The perturbed metabolism and metabolic mediates influence key signaling pathways in various prostatic pathological conditions. This short review article aids to highlight recent findings on metabolism, metabolic mechanisms, and mitochondrial metabolism as a possible route to finding a cure for prostate diseases, including prostate cancer. The effort to better understand the role that mitochondria plays in cancer metabolism and the biological meaning of defective and/or deleted mitochondrial DNA in cancer will also be discussed.

HMG-CoA synthase 1 is a synthetic lethal partner of BRAFV600E in human cancers

Contributions of metabolic changes to cancer development and maintenance have received increasing attention in recent years. Although many human cancers share similar metabolic alterations, it remains unclear whether oncogene-specific metabolic alterations are required for tumor development. Using an RNAi-based screen targeting the majority of the known metabolic proteins, we recently found that oncogenic BRAF^V600E up-regulates HMG-CoA lyase (HMGCL), which converts HMG-CoA to acetyl-CoA and a ketone body, acetoacetate, that selectively enhances BRAF^V600E-dependent MEK1 activation in human cancer. Here, we identified HMG-CoA synthase 1 (HMGCS1), the upstream ketogenic enzyme of HMGCL, as an additional "synthetic lethal" partner of BRAF^V600E Although HMGCS1 expression did not correlate with BRAF^V600E mutation in human melanoma cells, HMGCS1 was selectively important for proliferation of BRAF^V600E-positive melanoma and colon cancer cells but not control cells harboring active N/KRAS mutants, and stable knockdown of HMGCS1 only attenuated colony formation and tumor growth potential of BRAF^V600E melanoma cells. Moreover, cytosolic HMGCS1 that co-localized with HMGCL and BRAF^V600E was more important than the mitochondrial HMGCS2 isoform in BRAF^V600E-expressing cancer cells in terms of acetoacetate production. Interestingly, HMGCL knockdown did not affect HMGCS1 expression levels, whereas HMGCS1 knockdown caused a compensating increase in HMGCL protein level because of attenuated protein degradation. However, this increase did not reverse the reduced ketogenesis in HMGCS1 knockdown cells. Mechanistically, HMGCS1 inhibition decreased intracellular acetoacetate levels, leading to reduced BRAF^V600E-MEK1 binding and consequent MEK1 activation. We conclude that the ketogenic HMGCS1-HMGCL-acetoacetate axis may represent a promising therapeutic target for managing BRAF^V600E-positive human cancers.

ReactELISA: Monitoring a Carbon Nucleophilic Metabolite by ELISA-a Study of Lipid Metabolism

We here present a conceptually novel reaction-based ELISA principle (ReactELISA) for quantitation of the carbon nucleophilic lipid metabolite acetoacetate. Key to the assay is the utilization of a highly chemoselective Friedländer reaction that captures and simultaneously stabilizes the nucleophilic metabolite directly in the biological matrix. By developing a bifunctional biotinylated capture probe, the Friedländer-acetoacetate adduct can be trapped and purified directly in streptavidin coated wells. Finally, we outline the selection and refinement of a highly selective recombinant antibody for specific adduct quantitation. The setup is very robust and, as we demonstrate via miniaturization for microplate format, amenable for screening of compounds or interventions that alter lipid metabolism in liver cell cultures. The assay-principle should be extendable to quantitation of other nucleophilic or electrophilic and perhaps even more reactive metabolites provided suitable capture probes and antibodies.

Synthetic lethality: emerging targets and opportunities in melanoma

Great progress has been made in the treatment of melanoma through use of targeted therapies and immunotherapy. One approach that has not been fully explored is synthetic lethality, which exploits somatically acquired changes, usually driver mutations, to specifically kill tumour cells. We outline the various approaches that may be applied to identify synthetic lethal interactions and define how these interactions may drive drug discovery efforts.

Mitochondrial metabolism and energy sensing in tumor progression

Energy homeostasis is pivotal for cell fate since metabolic regulation, cell proliferation and death are strongly dependent on the balance between catabolic and anabolic pathways. In particular, metabolic and energetic changes have been observed in cancer cells even before the discovery of oncogenes and tumor suppressors, but have been neglected for a long time. Instead, during the past 20years a renaissance of the study of tumor metabolism has led to a revised and more accurate sight of the metabolic landscape of cancer cells. In this scenario, genetic, biochemical and clinical evidences place mitochondria as key actors in cancer metabolic restructuring, not only because there are energy and biosynthetic intermediates manufacturers, but also because occurrence of mutations in metabolic enzymes encoded by both nuclear and mitochondrial DNA has been associated to different types of cancer. Here we provide an overview of the possible mechanisms modulating mitochondrial energy production and homeostasis in the intriguing scenario of neoplastic cells, focusing on the double-edged role of 5'-AMP activated protein kinase in cancer metabolism. This article is part of a Special Issue entitled Mitochondria in Cancer, edited by Giuseppe Gasparre, Rodrigue Rossignol and Pierre Sonveaux.

Prevention of Dietary-Fat-Fueled Ketogenesis Attenuates BRAF V600E Tumor Growth

Lifestyle factors, including diet, play an important role in the survival of cancer patients. However, the molecular mechanisms underlying pathogenic links between diet and particular oncogenic mutations in human cancers remain unclear. We recently reported that the ketone body acetoacetate selectively enhances BRAF V600E mutant-dependent MEK1 activation in human cancers. Here we show that a high-fat ketogenic diet increased serum levels of acetoacetate, leading to enhanced tumor growth potential of BRAF V600E-expressing human melanoma cells in xenograft mice. Treatment with hypolipidemic agents to lower circulating acetoacetate levels or an inhibitory homolog of acetoacetate, dehydroacetic acid, to antagonize acetoacetate-BRAF V600E binding attenuated BRAF V600E tumor growth. These findings reveal a signaling basis underlying a pathogenic role of dietary fat in BRAF V600E-expressing melanoma, providing insights into the design of conceptualized "precision diets" that may prevent or delay tumor progression based on an individual's specific oncogenic mutation profile.

Multi-dimensional Roles of Ketone Bodies in Fuel Metabolism, Signaling, and Therapeutics

Ketone body metabolism is a central node in physiological homeostasis. In this review, we discuss how ketones serve discrete fine-tuning metabolic roles that optimize organ and organism performance in varying nutrient states and protect from inflammation and injury in multiple organ systems. Traditionally viewed as metabolic substrates enlisted only in carbohydrate restriction, observations underscore the importance of ketone bodies as vital metabolic and signaling mediators when carbohydrates are abundant. Complementing a repertoire of known therapeutic options for diseases of the nervous system, prospective roles for ketone bodies in cancer have arisen, as have intriguing protective roles in heart and liver, opening therapeutic options in obesity-related and cardiovascular disease. Controversies in ketone metabolism and signaling are discussed to reconcile classical dogma with contemporary observations.

Somatic mutations in solid tumors: a spectrum at the service of diagnostic armamentarium or an indecipherable puzzle? The morphological eyes looking for BRAF and somatic molecular detections on cyto-histological samples

This review article deals with the analysis and the detection of the morphological features associated with somatic mutations, mostly BRAFV600E mutation, on both cytological and histological samples of carcinomas. Few authors demonstrated that some architectural and specific cellular findings (i.e. polygonal eosinophilic cells defined as "plump cells" and sickle-shaped nuclei) are able to predict BRAF V600E mutation in both cytological and histological samples of papillary thyroid carcinoma (PTC) as well as in other carcinomas. In the current review article we evaluated the first comprehensive analysis of the morphological prediction of BRAFV600E and other somatic mutations in different malignant lesions with the description of the possible mechanisms beneath these morphologic features. The detection of predictive morphological features, mostly on FNAC, may add helpful information to the stratification of the malignant risk and personalized management of cancers. Additionally, the knowledge of the molecular mechanism of different oncogenic drivers can lead to the organ-specific triaging selection of cases and can provide significant insight for targeted therapies in different malignant lesions.

Deconstructing the Metabolic Networks of Oncogenic Signaling Using Targeted Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Metabolic reprogramming is recognized as an emerging hallmark of oncogenic signaling and cancer development. Hence the need to identify novel quantitative analytical platforms for studying metabolism in vitro and in vivo has dramatically increased. Here, we describe the experimental workflow for a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach involving positive/negative ion switching to analyze >250 metabolites of central carbon metabolism, nucleotides, and amino acids.

Mass Spectrometry Imaging in Oncology Drug Discovery

Over the last decade mass spectrometry imaging (MSI) has been integrated in to many areas of drug discovery and development. It can have significant impact in oncology drug discovery as it allows efficacy and safety of compounds to be assessed against the backdrop of the complex tumour microenvironment. We will discuss the roles of MSI in investigating compound and metabolite biodistribution and defining pharmacokinetic -pharmacodynamic relationships, analysis that is applicable to all drug discovery projects. We will then look more specifically at how MSI can be used to understand tumour metabolism and other applications specific to oncology research. This will all be described alongside the challenges of applying MSI to industry research with increased use of metrology for MSI.

Regulation of Ketone Body Metabolism and the Role of PPARα

Ketogenesis and ketolysis are central metabolic processes activated during the response to fasting. Ketogenesis is regulated in multiple stages, and a nuclear receptor peroxisome proliferator activated receptor α (PPARα) is one of the key transcription factors taking part in this regulation. PPARα is an important element in the metabolic network, where it participates in signaling driven by the main nutrient sensors, such as AMP-activated protein kinase (AMPK), PPARγ coactivator 1α (PGC-1α), and mammalian (mechanistic) target of rapamycin (mTOR) and induces hormonal mediators, such as fibroblast growth factor 21 (FGF21). This work describes the regulation of ketogenesis and ketolysis in normal and malignant cells and briefly summarizes the positive effects of ketone bodies in various neuropathologic conditions.

Enrichment of Metabolite-Binding Proteins by Affinity Elution in Tandem Hydrophobic Interaction Chromatography (AETHIC) Reveals RKIP Regulating ERK Signaling in an ATP-Dependent Manner

To elucidate the molecular mechanisms underlying the action of bioactive compounds such as metabolites, identification of their binding targets is essential. However, available techniques for enriching metabolite-binding proteins are practically restrained by special equipment requirements and laborious efforts. Here we have developed a novel method, affinity elution in tandem hydrophobic interaction chromatography (AETHIC), which enables enrichment of metabolite-binding proteins from a crude tissue extract. AETHIC constitutes two major steps, protein fractionation and affinity elution. The basic strategy of AETHIC uses a series of HIC matrices encompassing aliphatic chains of different length and thus provides a wide range of hydrophobicity for interactions with most proteins. Thereafter, target proteins are eluted selectively by a given ligand. As our first proof-of-principle, we demonstrated that AETHIC was able to enrich ATP-binding proteins from porcine brain extract. In addition, we have demonstrated that raf kinase inhibitory protein (RKIP) is an ATP-binding protein and ATP attenuates the interaction between RKIP and Raf-1. In parallel, short-term ATP depletion in cultured HEK293 cells augments interaction between RKIP and Raf-1, resulting in decreased activation of the downstream ERK signaling. Therefore, the ATP-binding function renders RKIP's inhibition on Raf-1 modulated by cellular ATP concentrations. These data shed light on how energy levels affect the propagation of cellular signaling. Taken together, the enclosed results advocate the potential of AETHIC in the study of metabolite-protein interactions.

Oncogene-directed alterations in cancer cell metabolism

Oncogenes are key drivers of tumor growth. Although several cancer-driving mechanisms have been identified, the role of oncogenes in shaping metabolic patterns in cancer cells is only beginning to be appreciated. Recent studies show that oncogenes directly regulate critical metabolic enzymes and metabolic signaling pathways. Here, we present evidence for oncogene-directed cancer metabolic regulation and discuss the importance of identifying underlying mechanisms that can be targeted for developing precision cancer therapies.

The complexities and versatility of the RAS-to-ERK signalling system in normal and cancer cells

The intricate dynamic control and plasticity of RAS to ERK mitogenic, survival and apoptotic signalling has mystified researches for more than 30 years. Therapeutics targeting the oncogenic aberrations within this pathway often yield unsatisfactory, even undesired results, as in the case of paradoxical ERK activation in response to RAF inhibition. A direct approach of inhibiting single oncogenic proteins misses the dynamic network context governing the network signal processing. In this review, we discuss the signalling behaviour of RAS and RAF proteins in normal and in cancer cells, and the emerging systems-level properties of the RAS-to-ERK signalling network. We argue that to understand the dynamic complexities of this control system, mathematical models including mechanistic detail are required. Looking into the future, these dynamic models will build the foundation upon which more effective, rational approaches to cancer therapy will be developed.

Oncogenic KRAS and BRAF Drive Metabolic Reprogramming in Colorectal Cancer

Metabolic reprogramming, in which altered utilization of glucose and glutamine supports rapid growth, is a hallmark of most cancers. Mutations in the oncogenes KRAS and BRAF drive metabolic reprogramming through enhanced glucose uptake, but the broader impact of these mutations on pathways of carbon metabolism is unknown. Global shotgun proteomic analysis of isogenic DLD-1 and RKO colon cancer cell lines expressing mutant and wild type KRAS or BRAF, respectively, failed to identify significant differences (at least 2-fold) in metabolic protein abundance. However, a multiplexed parallel reaction monitoring (PRM) strategy targeting 73 metabolic proteins identified significant protein abundance increases of 1.25-twofold in glycolysis, the nonoxidative pentose phosphate pathway, glutamine metabolism, and the phosphoserine biosynthetic pathway in cells with KRAS G13D mutations or BRAF V600E mutations. These alterations corresponded to mutant KRAS and BRAF-dependent increases in glucose uptake and lactate production. Metabolic reprogramming and glucose conversion to lactate in RKO cells were proportional to levels of BRAF V600E protein. In DLD-1 cells, these effects were independent of the ratio of KRAS G13D to KRAS wild type protein. A study of 8 KRAS wild type and 8 KRAS mutant human colon tumors confirmed the association of increased expression of glycolytic and glutamine metabolic proteins with KRAS mutant status. Metabolic reprogramming is driven largely by modest (<2-fold) alterations in protein expression, which are not readily detected by the global profiling methods most commonly employed in proteomic studies. The results indicate the superiority of more precise, multiplexed, pathway-targeted analyses to study functional proteome systems. Data are available through MassIVE Accession MSV000079486 at ftp://MSV000079486@massive.ucsd.edu.

When Morphology Meets Somatic Mutations: The New Possible Scenario in Thyroid Fine-Needle Aspiration

This study points to the analysis of the morphological features suggestive of somatic mutations, mostly the BRAFV600E mutation, on cytological samples of thyroid carcinomas. According to the literature, the application of ancillary techniques on cytology comes in handy as a challenging aid in ruling out a malignant outcome on both conventional and liquid-based cytological preparations. However, the evaluation of somatic mutations, including BRAFV600E, usually performed by DNA techniques, may have some limitations in a worldwide diffusion. In this perspective, few authors emphasized the morphological search for BRAFV600E mutations harbored in papillary thyroid carcinoma (PTC) and characterized by specific architectural and cellular findings (i.e. eosinophilic cells defined as 'plump cells' and sickle-shaped nuclei). Hence, the detection of eosinophilic cytoplasm of mutated PTC cells seems to suggest the possible involvement of the 'Warburg effect' pioneering the ability of cancer cells to convert glucose into lactic acid. The recent yields of immunohistochemical expression of monocarboxylate transporters in mutated PTCs may suggest the accumulation of lactate in these plump cells. Equally importantly, the detection of these morphological findings using fine-needle aspiration cytology may be helpful in triaging thyroid lesions and limiting costs. Additionally, it may lead to the stratification of the malignant risk and personalized management in cases with multifocal lesions.

Metabolic rewiring in melanoma

Oncogene-driven metabolic rewiring is an adaptation to low nutrient and oxygen conditions in the tumor microenvironment that enables cancer cells of diverse origin to hyperproliferate. Aerobic glycolysis and enhanced reliance on glutamine utilization are prime examples of such rewiring. However, tissue of origin as well as specific genetic and epigenetic changes determines gene expression profiles underlying these metabolic alterations in specific cancers. In melanoma, activation of the mitogen-activated protein kinase (MAPK) pathway driven by mutant BRAF or NRAS is a primary cause of malignant transformation. Activity of the MAPK pathway, as well as other factors, such as HIF1α, Myc and MITF, are among those that control the balance between non-oxidative and oxidative branches of central carbon metabolism. Here, we discuss the nature of metabolic alterations that underlie melanoma development and affect its response to therapy.

The Oct1 transcription factor and epithelial malignancies: Old protein learns new tricks

The metazoan-specific POU domain transcription factor family comprises activities underpinning developmental processes such as embryonic pluripotency and neuronal specification. Some POU family proteins efficiently bind an 8-bp DNA element known as the octamer motif. These proteins are known as Oct transcription factors. Oct1/POU2F1 is the only widely expressed POU factor. Unlike other POU factors it controls no specific developmental or organ system. Oct1 was originally described to operate at target genes associated with proliferation and immune modulation, but more recent results additionally identify targets associated with oxidative and cytotoxic stress resistance, metabolic regulation, stem cell function and other unexpected processes. Oct1 is pro-oncogenic in multiple contexts, and several recent reports provide broad evidence that Oct1 has prognostic and therapeutic value in multiple epithelial tumor settings. This review focuses on established and emerging roles of Oct1 in epithelial tumors, with an emphasis on mechanisms of transcription regulation by Oct1 that may underpin these findings. This article is part of a Special Issue entitled: The Oct Transcription Factor Family, edited by Dr. Dean Tantin.

Oct-1, to go or not to go? That is the PolII question

The Oct transcription factors recognise an octamer DNA element from which they regulate transcription of specific target genes. Oct-1 is the only member of the subfamily that is ubiquitously expressed and has a wide role in transcriptional control. Through interaction with various partner proteins, Oct-1 can modulate accessibility to the chromatin to recruit the transcription machinery and form the pre-initiation complex. The recruited PolII is induced to initiate transcription and stalled until elongation is triggered on interaction with signalling transcription factors. In this way, Oct-1 can fulfil general roles in transcription by opening the chromatin as well as transduce extracellular signals by relaying activation through various interacting partners. The emerging picture of Oct-1 is that of a complex and versatile transcription factor with fundamental functions in cell homeostasis and signal response in general as well as cell specific contexts. This article is part of a Special Issue entitled: The Oct Transcription Factor Family, edited by Dr. Dean Tantin.

Cancer's Fuel Choice: New Flavors for a Picky Eater

Otto Warburg discovered that cancer cells exhibit a high rate of glycolysis in the presence of ample oxygen, a process termed aerobic glycolysis, in 1924 (Warburg et al., 1924). Since then we have significantly advanced our understanding of cancers' fuel choice to meet their demands for energy and for the production of biosynthetic precursors. In this review, we will discuss the preferred nutrients of cancer cells and how they are utilized to satisfy their bioenergetic and biosynthetic needs. In addition, we will describe how cell intrinsic and extrinsic factors such as oncogene mutations, nutrient and oxygen availability, and other microenvironmental factors influence fuel choice.

Targeting metabolic reprogramming as a potential therapeutic strategy in melanoma

Metabolic reprogramming is a recognized hallmark of cancer. In order to support continued proliferation and growth, tumor cells must metabolically adapt to balance their bioenergetic and biosynthetic needs. To achieve this, cancer cells switch from mitochondrial oxidative phosphorylation to predominantly rely on glycolysis, a process known as the "Warburg effect". The BRAF oncogene has recently emerged as a critical regulator of this process in melanoma, bringing to the fore the importance of metabolic reprogramming in the pathogenesis and treatment of metastatic melanoma. In this review, we summarize our current understanding of oncogenic reprogramming of metabolism in BRAF and NRAS mutant melanoma, and highlight emerging evidence supporting a metabolic basis for MAPK pathway inhibitor resistance and metabolic vulnerabilities that may be exploited to overcome this.

Addicted to AA (Acetoacetate): A Point of Convergence between Metabolism and BRAF Signaling

In this issue Kang et al. (2015) show that oncogenic BRAF(V600E) stimulates expression of ketogenic enzyme 3-hydroxy-3-methylglutaryl-CoA lyase and promotes the formation of the ketone body acetoacetate, which subsequently enhances BRAF(V600E)/MEK/ERK signaling.

Melanoma: oncogenic drivers and the immune system

Advances and in-depth understanding of the biology of melanoma over the past 30 years have contributed to a change in the consideration of melanoma as one of the most therapy-resistant malignancies. The finding that oncogenic BRAF mutations drive tumor growth in up to 50% of melanomas led to a molecular therapy revolution for unresectable and metastatic disease. Moving beyond BRAF, inactivation of immune regulatory checkpoints that limit T cell responses to melanoma has provided targets for cancer immunotherapy. In this review, we discuss the molecular biology of melanoma and we focus on the recent advances of molecularly targeted and immunotherapeutic approaches.