The mitochondrial membrane potential (ΔΨm) is the main driver of oxidative phosphorylation (OXPHOS). The inner mitochondrial membrane (IMM), consisting of cristae and inner boundary membranes (IBM), is considered to carry a uniform ΔΨm. However, sequestration of OXPHOS components in cristae membranes necessitates a re‐examination of the equipotential representation of the IMM. We developed an approach to monitor ΔΨm at the resolution of individual cristae. We found that the IMM was divided into segments with distinct ΔΨm, corresponding to cristae and IBM. ΔΨm was higher at cristae compared to IBM. Treatment with oligomycin increased, whereas FCCP decreased, ΔΨm heterogeneity along the IMM. Impairment of cristae structure through deletion of MICOS‐complex components or Opa1 diminished this intramitochondrial heterogeneity of ΔΨm. Lastly, we determined that different cristae within the individual mitochondrion can have disparate membrane potentials and that interventions causing acute depolarization may affect some cristae while sparing others. Altogether, our data support a new model in which cristae within the same mitochondrion behave as independent bioenergetic units, preventing the failure of specific cristae from spreading dysfunction to the rest.

Altered metabolism is a hallmark of cancer growth, forming the conceptual basis for development of metabolic therapies as cancer treatments. We performed in vivo metabolic profiling and molecular analysis of lung squamous cell carcinoma (SCC) to identify metabolic nodes for therapeutic targeting. Lung SCCs adapt to chronic mTOR inhibition and suppression of glycolysis through the GSK3α/β signaling pathway, which upregulates glutaminolysis. Phospho-GSK3α/β protein levels are predictive of response to single-therapy mTOR inhibition while combinatorial treatment with the glutaminase inhibitor CB-839 effectively overcomes therapy resistance. In addition, we identified a conserved metabolic signature in a broad spectrum of hypermetabolic human tumors that may be predictive of patient outcome and response to combined metabolic therapies targeting mTOR and glutaminase.

The LKB1/STK11 tumor suppressor encodes a serine/threonine kinase which coordinates cell growth, polarity, motility, and metabolism. In non-small cell lung cancer, LKB1 is somatically inactivated in 25-30% of cases, often concurrently with activating KRAS mutation. Here, we employed an integrative approach to define novel therapeutic targets in KRAS-driven LKB1 mutant lung cancers. High-throughput RNAi screens in lung cancer cell lines from genetically engineered mouse models driven by activated KRAS with or without coincident Lkb1 deletion led to the identification of Dtymk, encoding deoxythymidylate kinase which catalyzes dTTP biosynthesis, as synthetically lethal with Lkb1 deficiency in mouse and human lung cancer lines. Global metabolite profiling demonstrated that Lkb1-null cells had striking decreases in multiple nucleotide metabolites as compared to the Lkb1-wt cells. Thus, LKB1 mutant lung cancers have deficits in nucleotide metabolism conferring hypersensitivity to DTYMK inhibition, suggesting that DTYMK is a potential therapeutic target in this aggressive subset of tumors.

The diagnostic definition of indeterminate lung nodules as malignant or benign poses a major challenge for clinicians. We discovered a potential marker, the sodium glucose transporter 2 (SGLT2), whose activity identified metabolically active lung premalignancy and early-stage lung adenocarcinoma (LADC). We found that SGLT2 is expressed early in lung tumorigenesis and is found specifically in pre-malignant lesions and well-differentiated adenocarcinomas. Of note, SGLT2 activity could be detected in vivo by positron emission tomography (PET) with the tracer methyl-4-[18F] fluorodeoxyglucose (Me4FDG), which specifically detects SGLT activity. Using a combination of immunohistochemistry and Me4FDG PET, we identified high expression and functional activity of SGLT2 in lung premalignancy and early-stage/low-grade LADC. Furthermore, selective targeting of SGLT2 with FDA-approved small molecule inhibitors, the gliflozins, greatly reduced tumor growth and prolonged survival in autochthonous mouse models and patient-derived xenografts of LADC. Targeting SGLT2 in lung tumors may intercept lung cancer progression at early stages of development by pairing Me4FDG PET imaging with therapy using SGLT2 inhibitors.

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Renal cell carcinomas (RCC) are emerging as a complex set of diseases with major socioeconomic impact and a continued rise in incidence throughout the world. As the field of urologic oncology faces these trends, several major genomic and mechanistic discoveries have altered our core understanding of this multitude of cancers, including several new rare subtypes of renal cancers. This review will examine these new findings, and place them in the context of the well-established association of clear cell RCC (ccRCC) with mutations in the von Hippel-Lindau (VHL) gene and resultant aberrant hypoxia inducible factor (HIF) signaling. The impact of novel ccRCC-associated genetic lesions on chromatin remodeling and epigenetic regulation is explored. The effects of VHL mutation on primary ciliary function, extracellular matrix homeostasis, and tumor metabolism are discussed. VHL proteostasis is reviewed, with the goal of harnessing the proteostatic machinery to refunctionalize mutant VHL. Translational efforts using molecular tools to understand discriminating features of ccRCC tumors and develop improved prognostic and predictive algorithms are presented and new therapeutics arising from the earliest molecular discoveries in ccRCC are summarized. By creating an integrated review of the key genomic and molecular biological disease characteristics of ccRCC and placing these data in the context of the evolving therapeutic landscape, we intend to facilitate interaction between basic, translational and clinical researchers involved in the treatment of this devastating disease, and accelerate progress towards its ultimate eradication.

A.J. performed transthoracic injections. G.A. performed a portion of the CT scans. M.M. and S.T.B. performed IHC staining and analyzed data. M.M. J.T.L. and A.J. performed in vitro 18 FBnTP uptake assays. M.M. did TMRE staining and western blots. M.C.F is a board-certified anatomic pathologist who performed the pathological analysis. L.S. and O.S. performed and guided respirometry experiments. S.S., C.M.W., A.G. and T.H. performed radio-tracer synthesis. D.D. and C.K. performed biochemical analysis of mitochondria. E.S. and H.C. performed metabolic analysis of lung tumors. S.M.D. contributed resources and critical feedback on the project. Data availability Source data for Western blots are provided with the paper as Supplementary Figure 1. Source data for Figures 1b-d; Figures 2d-g; Figures 3b, 3d, 3e; ED Figures 3c-e; ED Figures 4c, 4d; ED Figure 9a are provided with the paper. The data that support the findings of this study are available from the corresponding author upon reasonable request.

Cancer cells exhibit increased use of nutrients including glucose and glutamine to support the bioenergetic and biosynthetic demands of proliferation. We tested the small molecule inhibitor of glutaminase CB-839 in combination with erlotinib on EGFR mutant non-small cell lung cancer (NSCLC) as a therapeutic strategy to simultaneously impair cancer glucose and glutamine utilization and thereby suppress tumor growth. Here we show that CB-839 cooperates with erlotinib to drive energetic stress and activate the AMPK pathway in EGFR (del19) lung tumors. Tumor cells undergo metabolic crisis and cell death resulting in rapid tumor regression in vivo in mouse NSCLC xenografts. Consistently, positron emission tomography (PET) imaging with 18F-fluoro-2-deoxyglucose (18F-FDG) and 11C-Glutamine (11C-Gln) of xenografts indicated reduced glucose and glutamine uptake in tumors following CB-839 + erlotinib treatment. Therefore, PET imaging with 18F-FDG and 11C-Gln tracers can be used to non-invasively measure metabolic response to CB-839 and erlotinib combination therapy.