[Uptake of 2-NBDG by human breast cancer cells in vitro].

OBJECTIVE

The purpose of this study was to assess the feasibility of fluorescent 2-deoxyglucose analog, 2-[N-(7-nitrobenz-2-oxa-1, 3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG), that could be taken up by breast cancer cells highly expressing glucose transporter 1 (GLUT-1). The purpose of this study was to clarify if a fluorescent 2-deoxyglucose analog, 2-[N-(7-nitrobenz-2-oxa-1, 3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG), can be taken up by breast cancer cells highly expressing glucose transporter 1 (GLUT-1), and to assess whether it can be used as a targeting imaging agent.

METHODS

The expressions of GLUT-1 mRNA and protein in breast cancer MDA-MB-231 cells were detected by RT-PCR and immunohistochemistry, respectively. The difference of GLUT-1 protein expression between breast cancer MDA-MB-231 cells and MCF-7 cells was compared by Western blot. Secondly, MDA-MB-231 cells which were grown in 6-well plates were incubated with 2-NBDG, and the result of 2-NBDG uptake was analyzed by fluorescence microscopy and flow cytometry. The difference of 2-NBDG absorption in MDA-MB-231 and MCF-7 cells was compared by flow cytometry.

RESULTS

The results of RT-PCR and immunohistochemistry confirmed that MDA-MB-231 cells highly expressed GLUT-1. Furthermore, Western blot revealed that GLUT-1 expression of MDA-MB-231 cells (0.946 ± 0.007) was higher than that in the MCF-7 cells (0.833 ± 0.010). Fluorescence microscopic and flow cytometric analysis showed that 2-NBDG was uptaken rapidly by MDA-MB-231 cells. Addition of 50 mmol/L D-glucose to the media with 2-NBDG reduced its uptake by 46.0%. Moreover, flow cytometry indicated that the fluorescence intensity of MDA-MB-231 cells (25.10 ± 0.57) was higher than that of MCF-7 cells (10.12 ± 0.62) when incubated with 2-NBDG for 20 minutes.

CONCLUSION

The preliminary data clearly demonstrate that 2-NBDG is taken up and accumulated in breast cancer cells that highly express GLUT-1, and may be used as an optical probe for glucose uptake in hypermetabolic malignant cells.