Uptake of a fluorescent deoxyglucose analog (2-NBDG) in tumor cells.

A new fluorescent analog of D -glucose was recently developed by [Yoshioka K, Takahashi H, Homma T, Sato M, Ki Bong O, Nemoto Y, Matsuoka H (1996) A novel fluorescent derivative of glucose applicable to the assessment of glucose uptake activity of Escherichia coli. Biochim Biophys Acta 1289:5-9] and shown to be transported into normal cells. The purpose of this preliminary study was to assess the use of this fluorescent 2-deoxyglucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG), as a sensitive probe for monitoring glucose uptake into malignant tumor cells. MCF-7 breast cancer epithelial cells were grown and plated on coverslips for analysis of 2-NBDG uptake via fluorescence imaging microscopy. Steady-state fluorescence analysis of 2-NBDG uptake displayed rapid uptake for the first one to five minutes, then slowed, reaching an apparent maximum uptake near 20-30 minutes. Addition of 5 mM D -glucose to the media markedly reduced 2-NBDG uptake. Uptake of 2-NBDG in nonmalignant epithelial cells (M-1 epithelial cells) was slow, averaging less than 20% of that observed for tumorigenic cells, the MCF-7 breast cancer cells and the HepG2 liver cancer cell line. The preliminary data clearly demonstrate a rapid uptake of 2-NBDG into tumor cells that can be monitored by fluorescence imaging analysis. The uptake displays saturation and competition with D -glucose, all properties expected for 2-NBDG uptake and retention in cancer cells. Additional studies, including comparisons among other malignant cell lines and control cells, will be needed to fully characterize the kinetic properties of 2-NBDG uptake and the potential use of this 2-DG analog as a probe for glucose uptake in malignant cells.