2-NBDG

2-NBDG fluorescence imaging of hypermetabolic circulating tumor cells in mouse xenograft model of breast cancer.[Pubmed:23054302]

J Fluoresc. 2013 Jan;23(1):213-20.

OBJECTIVES: To determine use of 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG) as a tracer for detection of hypermetabolic circulating tumor cells (CTC) by fluorescence imaging. PROCEDURES: Human breast cancer cells were implanted in the mammary gland fat pad of athymic mice to establish orthotopic human breast cancer xenografts as a mouse model of circulating breast cancer cells. Near-infrared fluorescence imaging of the tumor-bearing mice injected with 2-DeoxyGlucosone 750 (2-DG 750) was conducted to assess glucose metabolism of xenograft tumors. Following incubation with fluorescent 2-NBDG, circulating breast cancer cells in the blood samples collected from the tumor-bearing mice were collected by magnetic separation, followed by fluorescence imaging for 2-NBDG uptake by circulating breast cancer cells, and correlation of the number of hypermetabolic circulating breast cancer cells with tumor size at the time when the blood samples were collected. RESULTS: Human breast cancer xenograft tumors derived from MDA-MB-231, BT474, or SKBR-3 cells were visualized on near-infrared fluorescence imaging of the tumor-bearing mice injected with 2-DG 750. Hypermetabolic circulating breast cancer cells with increased uptake of fluorescent 2-NBDG were detected in the blood samples from tumor-bearing mice and visualized by fluorescence imaging, but not in the blood samples from normal control mice. The number of hypermetabolic circulating breast cancer cells increased along with growth of xenograft tumors, with the number of hypermetabolic circulating breast cancer cells detected in the mice bearing MDA-MB231 xenografts larger than those in the mice bearing BT474 or SKBR-3 xenograft tumors. CONCLUSIONS: Circulating breast cancer cells with increased uptake of fluorescent 2-NBDG were detected in mice bearing human breast cancer xenograft tumors by fluorescence imaging, suggesting clinical use of 2-NBDG as a tracer for fluorescence imaging of hypermetabolic circulating breast cancer cells.

Transport of a Fluorescent Analogue of Glucose (2-NBDG) versus Radiolabeled Sugars by Rumen Bacteria and Escherichia coli.[Pubmed:27096355]

Biochemistry. 2016 May 10;55(18):2578-89.

Fluorescent tracers have been used to measure solute transport, but transport kinetics have not been evaluated by comparison of radiolabeled tracers. Using Streptococcus equinus JB1 and other bacteria, the objective of this study was to determine if a fluorescent analogue of glucose (2-NBDG) would be transported with the same kinetics and transporters as [(14)C]glucose. We uniquely modified a technique for measuring transport of radiolabeled tracers so that transport of a fluorescent tracer (2-NBDG) could also be measured. Deploying this technique for S. equinus JB1, we could detect 2-NDBG transport quantitatively and within 2 s. We found the Vmax of 2-NBDG transport was 2.9-fold lower than that for [(14)C]glucose, and the Km was 9.9-fold lower. Experiments with transport mutants suggested a mannose phosphotransferase system (PTS) was responsible for 2-NBDG transport in S. equinus JB1 as well as Escherichia coli. Upon examination of strains from 12 species of rumen bacteria, only the five that possessed a mannose PTS were shown to transport 2-NBDG. Those five uniformly transported [(14)C]mannose and [(14)C]deoxyglucose (other glucose analogues at the C-2 position) at high velocities. Species that did not transport 2-NBDG at detectable velocities did not possess a mannose PTS, though they collectively possessed several other glucose transporters. These results, along with retrospective genomic analyses of previous 2-NBDG studies, suggest that only a few bacterial transporters may display high activity toward 2-NBDG. Fluorescent tracers have the potential to measure solute transport qualitatively, but their bulky fluorescent groups may restrict (i) activity of many transporters and (ii) use for quantitative measurement.

Syzygium aqueum leaf extract and its bioactive compounds enhances pre-adipocyte differentiation and 2-NBDG uptake in 3T3-L1 cells.[Pubmed:23122070]

Food Chem. 2013 Jan 15;136(2):354-63.

The insulin-like and/or insulin-sensitising effects of Syzygium aqueum leaf extract and its six bioactive compounds; 4-hydroxybenzaldehyde, myricetin-3-O-rhamnoside, europetin-3-O-rhamnoside, phloretin, myrigalone-G and myrigalone-B were investigated in 3T3-L1 adipocytes. We observed that, S. aqueum leaf extract (0.04-5 mug/ml) and its six bioactive compounds (0.08-10 muM) at non-cytotoxic concentrations were effectively enhance adipogenesis, stimulate glucose uptake and increase adiponectin secretion in 3T3-L1 adipocytes. Clearly, the compounds myricetin-3-O-rhamnoside and europetin-3-O-rhamnoside showed insulin-like and insulin-sensitising effects on adipocytes from a concentration of 0.08 muM. These compounds were far better than rosiglitazone and the other isolated compounds in enhancing adipogenesis, stimulating 2-NBDG uptake and increasing adiponectin secretion at all the concentrations tested. These suggest the antidiabetic potential of S. aqueum leaf extract and its six bioactive compounds. However, further molecular interaction studies to explain the mechanisms of action are highly warranted.

2-NBDG as a marker for detecting glucose uptake in reactive astrocytes exposed to oxygen-glucose deprivation in vitro.[Pubmed:25091860]

J Mol Neurosci. 2015 Jan;55(1):126-130.

Glucose is a necessary source of energy for sustaining cell activities and homeostasis in the brain. Enhanced glucose uptake protects cells during energy depletion including brain ischemia. Astrocytes enhance their glucose uptake during ischemia to supply substrates to neurons and thus support neuronal survival. Radiolabeled substrates are commonly used for in vitro measurement of glucose uptake in astrocytes. Here we optimized a method to measure glucose uptake by astrocytes during oxygen-glucose deprivation (OGD) using the fluorescent substrate 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG). Uptake buffers for 2-NBDG were the same as for (14)C-labeled alpha-methyl-D-glucopyranoside. Cell lysis buffer was optimized for observing the fluorescence of 2-NBDG, and Hoechst 33258 DNA staining was used for normalization of the 2-NBDG concentration. Uptake was performed on cultures of primary astrocytes by incubating the cells at 37 degrees C in buffer containing 25-200 muM 2-NBDG. Flow cytometry was performed to visualize uptake in intact cells, and a fluorescence microplate reader was used to measure the intracellular concentration of 2-NBDG in cell homogenates. 2-NBDG uptake was concentration dependent in astrocytes that were exposed or not exposed to OGD. OGD significantly increased 2-NBDG uptake by about 1.2 to 2.5 times in astrocytes compared to control cells. These results show that 2-NBDG can be used to detect glucose transport in astrocytes exposed to OGD.

A real-time method of imaging glucose uptake in single, living mammalian cells.[Pubmed:17406637]

Nat Protoc. 2007;2(3):753-62.

This protocol details a method for monitoring glucose uptake into single, living mammalian cells using a fluorescent D-glucose derivative, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG), as a tracer. The specifically designed chamber and superfusion system for evaluating 2-NBDG uptake into cells in real time can be combined with other fluorescent methods such as Ca2+ imaging and the subsequent immunofluorescent classification of cells exhibiting divergent 2-NBDG uptake. The whole protocol, including immunocytochemistry, can be completed within 2 d (except for cell culture). The procedure for 2-NBDG synthesis is also presented.