posted on 2005-07-20, 00:00authored byKristine Glunde, Catherine A. Foss, Tomoyo Takagi, Flonne Wildes, Zaver M. Bhujwalla
Lysosomes contain multiple proteases, which play a crucial role in breast cancer invasion and
metastasis. Noninvasive labeling of lysosomes in breast cancer cells and solid breast tumor models is
therefore useful to study lysosomal trafficking and its role in invasion. We have synthesized a novel
compound, 6‘-O-lissamine-rhodamine B-glucosamine, to fluorescently label lysosomes, and evaluated
the compound in human breast cancer cells in cell culture or in orthotopic human breast cancer models.
We demonstrated that this novel compound biosynthetically labeled lysosomal proteins following
addition to cell culture medium or following intravenous injection into mouse models of breast cancer.
Fluorescence from 6‘-O-lissamine-rhodamine B-glucosamine colocalized with several well-established
lysosomal markers, such as lysosome-associated proteins 1 and 2 (LAMP-1 and -2) and CD63. We
also demonstrated the feasibility of performing in vivo fluorescence imaging of 6‘-O-lissamine-rhodamine B-glucosamine to image lysosomes in human breast cancer models.