The ability of a cancer cell to detach from the primary tumor and move to distant sites is fundamental to a lethal cancer phenotype. Metabolic transformations are associated with highly motile aggressive cellular phenotypes in tumor progression. Here, we report that cancer cell motility requires increased utilization of the glycolytic pathway. Mesenchymal cancer cells exhibited higher aerobic glycolysis compared to epithelial cancer cells while no significant change was observed in mitochondrial ATP production rate. Higher glycolysis was associated with increased rates of cytoskeletal remodeling, greater cell traction forces and faster cell migration, all of which were blocked by inhibition of glycolysis, but not by inhibition of mitochondrial ATP synthesis. Thus, our results demonstrate that cancer cell motility and cytoskeleton rearrangement is energetically dependent on aerobic glycolysis and not oxidative phosphorylation. Mitochondrial derived ATP is insufficient to compensate for inhibition of the glycolytic pathway with regard to cellular motility and CSK rearrangement, implying that localization of ATP derived from glycolytic enzymes near sites of active CSK rearrangement is more important for cell motility than total cellular ATP production rate. These results extend our understanding of cancer cell metabolism, potentially providing a target metabolic pathway associated with aggressive disease.

Brown adipose tissue (BAT) has a unique capacity to expend calories by decoupling energy expenditure from ATP production, therefore BAT could realize therapeutic potential to treat metabolic diseases such as obesity and type 2 diabetes. Recent studies have investigated markers and function of native BAT, however, successful therapies will rely on methods that supplement the small existing pool of brown adipocytes in adult humans. In this study, we engineered BAT from both human and rat adipose precursors and determined whether these ex vivo constructs could mimic in vivo tissue form and metabolic function. Adipose-derived stem cells (ASCs) were isolated from several sources, human white adipose tissue (WAT), rat WAT, and rat BAT, then differentiated toward both white and brown adipogenic lineages in two-dimensional and three-dimensional (3D) culture conditions. ASCs derived from WAT were successfully differentiated in 3D poly(ethylene glycol) hydrogels into mature adipocytes with BAT phenotype and function, including high uncoupling protein 1 (UCP1) mRNA and protein expression and increased metabolic activity (basal oxygen consumption, proton leak, and maximum respiration). By utilizing this "browning" process, the abundant and accessible WAT stem cell population can be engineered into 3D tissue constructs with the metabolic capacity of native BAT, ultimately for therapeutic intervention in vivo and as a tool for studying BAT and its metabolic properties.

Cellular bioenergetics and redox (reduction-oxidation) play an important role in cell proliferation and differentiation, key aspects of building new tissues. In the present study, we examined the metabolic characteristics of human adipose-derived stem cells (hASCs) during proliferation and differentiation in both monolayer and threedimensional biomaterial scaffolds. In monolayer, hASCs exhibited higher glycolysis and lower ox-phos as compared to both adipogenic and osteogenic differentiated cells, and hASCs demonstrated the Warburg effect (aerobic glycolysis). However, reactive oxygen species (ROS) levels increased during adipogenic differentiation, but decreased during osteogenic differentiation. Similarly, a decrease in ROS levels along with a higher mitochondrial membrane potential and viability was observed in hASCs encapsulated in poly(ethylene glycol) (PEG) hydrogels containing an adhesion peptide (RGD), compared to PEG hydrogels with a scrambled control peptide (GRD), demonstrating that adhesion-dependent signaling can also regulate ROS production and bioenergetics. As a result, we hypothesized that we could modulate osteogenesis in PEG hydrogels containing the adhesion peptide (RGD) by further reducing ROS levels using a small therapeutic molecule, L-carnitine, a metabolite with purported antioxidant effects. We observed reduced ROS levels, no effect on mitochondrial membrane potential, and increased osteogenic differentiation and tissue production in cells in the presence of L-carnitine. These results suggest the potential to manipulate tissue production by modulating cellular metabolism.

The objective of the present study was to characterize the trkB receptor immunoreactive (-ir) cells in the intermediolateral cell column (IML) of the upper thoracic spinal cord. Small trkB-ir cells (area =56.1 +/− 4.4 µm 2 ) observed in the IML showed characteristics of oligodendrocytes and were frequently observed in close apposition to choline acetyltransferase (ChAT)-ir cell bodies. Large trkB-ir cells (area =209.3 +/− 25.2 µm 2 ) showed immunoreactivity for the neuronal marker NeuN, indicating their neuronal phenotype, as well as for ChAT, a marker for preganglionic neurons. TrkB and ChAT were co-localized in IML neurons primarily in cases that had received in vivo administration of nerve growth factor (NGF). These findings reveal two different cell types, oligodendrocytes and neurons, in the IML of the spinal cord that show trkB immunoreactivity, suggesting their regulation by BDNF and/or NT-4. In addition, there is evidence that NGF may play a role in the regulation of trkB-ir preganglionic neurons in the IML. Keywords preganglionic neurons; BDNF; NT-4; oligodendrocytes; sympatheticThe regulation of neurons and glial cells in the spinal cord is poorly characterized. TrkB expressing cells have been reported in the spinal cord, suggesting that they are regulated by either brain derived neurotrophic factor (BDNF) and/or neurotrophin -4 (NT-4). For example, in the lower intermediolateral cell column (IML; T7-T10), pre-ganglionic neurons have been shown to express trkB mRNA, are trkB immunoreactive (-ir) [17], and appear to be dependent on neurotrophin-4 (NT-4) derived from adrenal medullary chromaffin cells for survival [16]. However, retrograde transport of NT-4 from the target could not be demonstrated in these preganglionic neurons, and thus the exact mechanisms involved in the NT-4-mediated survival of the lower intermediolateral cell column are not known. Preganglionic neurons located in the IML of the upper thoracic cord may be regulated by brain-derived neurotrophic factor (BDNF) , though these phenomena have not been well documented.In addition to preganglionic neurons, trkB-ir glial cells have been reported in the motor areas of the lumbar spinal cord [19] and were shown to be altered by exercise [13]. The extent to which the trkB-ir glial cells were present in the upper thoracic cord has not been described.*Corresponding author, Lori G. Isaacson, Center for Neuroscience and Behavior, Department of Zoology, Miami University, 280 Pearson Hall, Oxford, OH 45056, Fax: 513-529-6900, isaacslg@muohio.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. The go...