Breast cancer cells that preferentially metastasize to lung or bone are more glycolytic, synthesize serine at greater rates, and consume less ATP and NADPH than parent MDA-MB-231 cells.

Gene expression signatures associated with breast cancer metastases suggest that metabolic re-wiring is important for metastatic growth in lungs, bones, and other organs. However, since pathway fluxes depend on additional factors such as ATP demand, allosteric effects, and post-translational modification, flux analysis is necessary to conclusively establish phenotypes. In this study, the metabolic phenotypes of breast cancer cell lines with low (T47D) or high (MDA-MB-231) metastatic potential, as well as lung (LM)- and bone (BoM)-homing lines derived from MDA-MB-231 cells, were assessed by C metabolite labeling from [1,2-C] glucose or [5-C] glutamine and the rates of nutrient and oxygen consumption and lactate production.

Targeting Histone Demethylases in MYC-Driven Neuroblastomas with Ciclopirox.

Histone lysine demethylases facilitate the activity of oncogenic transcription factors, including possibly MYC. Here we show that multiple histone demethylases influence the viability and poor prognosis of neuroblastoma cells, where MYC is often overexpressed. We also identified the approved small-molecule antifungal agent ciclopirox as a novel pan-histone demethylase inhibitor.

Targeting Metabolic Reprogramming by Influenza Infection for Therapeutic Intervention.

Influenza is a worldwide health and financial burden posing a significant risk to the immune-compromised, obese, diabetic, elderly, and pediatric populations. We identified increases in glucose metabolism in the lungs of pediatric patients infected with respiratory pathogens. Using quantitative mass spectrometry, we found metabolic changes occurring after influenza infection in primary human respiratory cells and validated infection-associated increases in c-Myc, glycolysis, and glutaminolysis.

Polarization and asymmetry in T cell metabolism.

T cell activation results in a rapidly proliferating T cell endowed with a metabolic phenotype necessary for growth and division. However, before the cell can proceed towards this burst of cell division a phase of quiescence occurs, during which the basic mechanisms governing regulation of metabolic reprograming are established. This review focuses on key cellular processes controlling early metabolic regulation and how these circuits of metabolic control dictate distinct cellular fates upon the first asymmetric division.

Metabolic maintenance of cell asymmetry following division in activated T lymphocytes.

Asymmetric cell division, the partitioning of cellular components in response to polarizing cues during mitosis, has roles in differentiation and development. It is important for the self-renewal of fertilized zygotes in Caenorhabditis elegans and neuroblasts in Drosophila, and in the development of mammalian nervous and digestive systems. T lymphocytes, upon activation by antigen-presenting cells (APCs), can undergo asymmetric cell division, wherein the daughter cell proximal to the APC is more likely to differentiate into an effector-like T cell and the distal daughter is more likely to differentiate into a memory-like T cell.

Proinflammatory signal suppresses proliferation and shifts macrophage metabolism from Myc-dependent to HIF1α-dependent.

As a phenotypically plastic cellular population, macrophages change their physiology in response to environmental signals. Emerging evidence suggests that macrophages are capable of tightly coordinating their metabolic programs to adjust their immunological and bioenergetic functional properties, as needed. Upon mitogenic stimulation, quiescent macrophages enter the cell cycle, increasing their bioenergetic and biosynthetic activity to meet the demands of cell growth.

Apoptosis-Inducing-Factor-Dependent Mitochondrial Function Is Required for T Cell but Not B Cell Function.

The role of apoptosis inducing factor (AIF) in promoting cell death versus survival remains controversial. We report that the loss of AIF in fibroblasts led to mitochondrial electron transport chain defects and loss of proliferation that could be restored by ectopic expression of the yeast NADH dehydrogenase Ndi1. Aif-deficiency in T cells led to decreased peripheral T cell numbers and defective homeostatic proliferation, but thymic T cell development was unaffected.

Mito-protective autophagy is impaired in erythroid cells of aged mtDNA-mutator mice.

Somatic mitochondrial DNA (mtDNA) mutations contribute to the pathogenesis of age-related disorders, including myelodysplastic syndromes (MDS). The accumulation of mitochondria harboring mtDNA mutations in patients with these disorders suggests a failure of normal mitochondrial quality-control systems. The mtDNA-mutator mice acquire somatic mtDNA mutations via a targeted defect in the proofreading function of the mtDNA polymerase, PolgA, and develop macrocytic anemia similar to that of patients with MDS.

Protective roles for caspase-8 and cFLIP in adult homeostasis.

Caspase-8 or cellular FLICE-like inhibitor protein (cFLIP) deficiency leads to embryonic lethality in mice due to defects in endothelial tissues. Caspase-8(-/-) and receptor-interacting protein kinase-3 (RIPK3)(-/-), but not cFLIP(-/-) and RIPK3(-/-), double-knockout animals develop normally, indicating that caspase-8 antagonizes the lethal effects of RIPK3 during development. Here, we show that the acute deletion of caspase-8 in the gut of adult mice induces enterocyte death, disruption of tissue homeostasis, and inflammation, resulting in sepsis and mortality.

Receptor interacting protein kinase 2-mediated mitophagy regulates inflammasome activation during virus infection.

NOD2 receptor and the cytosolic protein kinase RIPK2 regulate NF-κB and MAP kinase signaling during bacterial infections, but the role of this immune axis during viral infections has not been addressed. We demonstrate that Nod2(-/-) and Ripk2(-/-) mice are hypersusceptible to infection with influenza A virus. Ripk2(-/-) cells exhibited defective autophagy of mitochondria (mitophagy), leading to enhanced mitochondrial production of superoxide and accumulation of damaged mitochondria, which resulted in greater activation of the NLRP3 inflammasome and production of IL-18.

Anti-apoptotic MCL-1 localizes to the mitochondrial matrix and couples mitochondrial fusion to respiration.

MCL-1, an anti-apoptotic BCL-2 family member that is essential for the survival of multiple cell lineages, is also among the most highly amplified genes in cancer. Although MCL-1 is known to oppose cell death, precisely how it functions to promote survival of normal and malignant cells is poorly understood. Here, we report that different forms of MCL-1 reside in distinct mitochondrial locations and exhibit separable functions.

The transcription factor Myc controls metabolic reprogramming upon T lymphocyte activation.

To fulfill the bioenergetic and biosynthetic demand of proliferation, T cells reprogram their metabolic pathways from fatty acid β-oxidation and pyruvate oxidation via the TCA cycle to the glycolytic, pentose-phosphate, and glutaminolytic pathways. Two of the top-ranked candidate transcription factors potentially responsible for the activation-induced T cell metabolic transcriptome, HIF1α and Myc, were induced upon T cell activation, but only the acute deletion of Myc markedly inhibited activation-induced glycolysis and glutaminolysis in T cells. Glutamine deprivation compromised activation-induced T cell growth and proliferation, and this was partially replaced by nucleotides and polyamines, implicating glutamine as an important source for biosynthetic precursors in active T cells.

Mitochondrial dysfunction in ataxia-telangiectasia.

Ataxia-telangiectasia mutated (ATM) plays a central role in DNA damage responses, and its loss leads to development of T-cell malignancies. Here, we show that ATM loss also leads to intrinsic mitochondrial abnormalities in thymocytes, including elevated reactive oxygen species, increased aberrant mitochondria, high cellular respiratory capacity, and decreased mitophagy. A fraction of ATM protein is localized in mitochondria, and it is rapidly activated by mitochondrial dysfunction.

Toll-like receptor signaling in the lysosomal pathways.

The lysosomal pathway digests material received by two main routes, phagocytosis and autophagy. Cells use phagocytosis to ingest extracellular particles by invaginations of the plasma membrane. In autophagy, a double membrane structure isolates portions of the cytoplasm to target it for degradation.

Multiple roles for the C-terminal tail of the chemokine scavenger D6.

D6 is a heptahelical receptor that suppresses inflammation and tumorigenesis by scavenging extracellular pro-inflammatory CC chemokines. Previous studies suggested this is dependent on constitutive trafficking of stable D6 protein to and from the cell surface via recycling endosomes. By internalizing chemokine each time it transits the cell surface, D6 can, over time, remove large quantities of these inflammatory mediators.

GAPDH and autophagy preserve survival after apoptotic cytochrome c release in the absence of caspase activation.

In cells undergoing apoptosis, mitochondrial outer-membrane permeabilization (MOMP) is followed by caspase activation promoted by released cytochrome c. Although caspases mediate the apoptotic phenotype, caspase inhibition is generally not sufficient for survival following MOMP; instead cells undergo a "caspase-independent cell death" (CICD). Thus, MOMP may represent a point of commitment to cell death.

Orexin-1 receptor-cannabinoid CB1 receptor heterodimerization results in both ligand-dependent and -independent coordinated alterations of receptor localization and function.

Following inducible expression in HEK293 cells, the human orexin-1 receptor was targeted to the cell surface but became internalized following exposure to the peptide agonist orexin A. By contrast, constitutive expression of the human cannabinoid CB1 receptor resulted in a predominantly punctate, intracellular distribution pattern consistent with spontaneous, agonist-independent internalization. Expression of the orexin-1 receptor in the presence of the CB1 receptor resulted in both receptors displaying the spontaneous internalization phenotype.

The chemokine receptor CCX-CKR mediates effective scavenging of CCL19 in vitro.

The chemokines CCL19, CCL21 and CCL25, by signalling through the receptors CCR7 or CCR9, play critical roles in leukocyte homing. They also bind another heptahelical surface protein, CCX-CKR. CCX-CKR cannot couple to typical chemokine receptor signalling pathways or mediate chemotaxis, and its function remains unclear.

Interactions between the Mas-related receptors MrgD and MrgE alter signalling and trafficking of MrgD.

When expressed via an inducible promoter in human embryonic kidney 293 cells, the rat Mas-related gene D (rMrgD) receptor responded to beta-alanine but not L-alanine by elevating intracellular [Ca(2+)], stimulating phosphorylation of the mitogenactivated protein kinases known as extracellular signal-regulated kinase (ERK) 1 and ERK2 and translocating from the plasma membrane to punctate intracellular vesicles. By contrast, the related rat Mas-related gene E (rMrgE) receptor did not respond to beta-alanine. Coexpression of rMrgD with rMrgE, which occurs in peripheral nociceptive neurons, allowed coimmunoprecipitation of the two receptors and resulted in the detection of cell surface rMrgD-rMrgE heterodimers via timeresolved fluorescence resonance energy transfer.

The sustainability of interactions between the orexin-1 receptor and beta-arrestin-2 is defined by a single C-terminal cluster of hydroxy amino acids and modulates the kinetics of ERK MAPK regulation.

The orexin-1 receptor interacts with beta-arrestin-2 in an agonist-dependent manner. In HEK-293T cells, these two proteins became co-internalized into acidic endosomes. Truncations from the C-terminal tail did not prevent agonist-induced internalization of the orexin-1 receptor or alter the pathway of internalization, although such mutants failed to interact with beta-arrestin-2 in a sustained manner or produce its co-internalization.