A Novel Method of Imaging Lysosomes in Living Human Mammary Epithelial Cells

Cancer cells invade by secreting degradative enzymes which, under normal conditions, are sequestered in lysosomal vesicles. The ability to noninvasively label lysosomes and track lysosomal trafficking would be extremely useful to understand the mechanisms by which degradative enzymes are secreted in...

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Main Authors: Kristine Glunde, Sandra E. Guggino, Yoshitaka Ichikawa, Zaver M. Bhujwalla
Format: Article
Language:English
Published: SAGE Publications 2003-01-01
Series:Molecular Imaging
Online Access:https://doi.org/10.1162/15353500200302142
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author Kristine Glunde
Sandra E. Guggino
Yoshitaka Ichikawa
Zaver M. Bhujwalla
author_facet Kristine Glunde
Sandra E. Guggino
Yoshitaka Ichikawa
Zaver M. Bhujwalla
author_sort Kristine Glunde
collection DOAJ
description Cancer cells invade by secreting degradative enzymes which, under normal conditions, are sequestered in lysosomal vesicles. The ability to noninvasively label lysosomes and track lysosomal trafficking would be extremely useful to understand the mechanisms by which degradative enzymes are secreted in the presence of pathophysiological environments, such as hypoxia and acidic extracellular pH, which are frequently encountered in solid tumors. In this study, a novel method of introducing a fluorescent label into lysosomes of human mammary epithelial cells (HMECs) was evaluated. Highly glycosylated lysosomal membrane proteins were labeled with a newly synthesized compound, 5-dimethylamino-naphthalene-1-sulfonic acid 5-amino-3,4,6-trihydroxy-tetrahydro-pyran-2-ylmethyl ester (6- O -dansyl-GlcNH 2 ). The ability to optically image lysosomes using this new probe was validated by determining the colocalization of the fluorescence from the dansyl group with immunofluorescent staining of two well-established lysosomal marker proteins, LAMP-1 and LAMP-2. The location of the dansyl group in lysosomes was also verified by using an anti-dansyl antibody in Western blots of lysosomes isolated using isopycnic density gradient centrifugation. This novel method of labeling lysosomes biosynthetically was used to image lysosomes in living HMECs perfused in a microscopy-compatible cell perfusion system.
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spelling doaj.art-90f62e8ee32d43d69ad13d508f755a2b2024-03-02T17:21:41ZengSAGE PublicationsMolecular Imaging1536-01212003-01-01210.1162/1535350020030214210.1162_15353500200302142A Novel Method of Imaging Lysosomes in Living Human Mammary Epithelial CellsKristine GlundeSandra E. GugginoYoshitaka IchikawaZaver M. BhujwallaCancer cells invade by secreting degradative enzymes which, under normal conditions, are sequestered in lysosomal vesicles. The ability to noninvasively label lysosomes and track lysosomal trafficking would be extremely useful to understand the mechanisms by which degradative enzymes are secreted in the presence of pathophysiological environments, such as hypoxia and acidic extracellular pH, which are frequently encountered in solid tumors. In this study, a novel method of introducing a fluorescent label into lysosomes of human mammary epithelial cells (HMECs) was evaluated. Highly glycosylated lysosomal membrane proteins were labeled with a newly synthesized compound, 5-dimethylamino-naphthalene-1-sulfonic acid 5-amino-3,4,6-trihydroxy-tetrahydro-pyran-2-ylmethyl ester (6- O -dansyl-GlcNH 2 ). The ability to optically image lysosomes using this new probe was validated by determining the colocalization of the fluorescence from the dansyl group with immunofluorescent staining of two well-established lysosomal marker proteins, LAMP-1 and LAMP-2. The location of the dansyl group in lysosomes was also verified by using an anti-dansyl antibody in Western blots of lysosomes isolated using isopycnic density gradient centrifugation. This novel method of labeling lysosomes biosynthetically was used to image lysosomes in living HMECs perfused in a microscopy-compatible cell perfusion system.https://doi.org/10.1162/15353500200302142
spellingShingle Kristine Glunde
Sandra E. Guggino
Yoshitaka Ichikawa
Zaver M. Bhujwalla
A Novel Method of Imaging Lysosomes in Living Human Mammary Epithelial Cells
Molecular Imaging
title A Novel Method of Imaging Lysosomes in Living Human Mammary Epithelial Cells
title_full A Novel Method of Imaging Lysosomes in Living Human Mammary Epithelial Cells
title_fullStr A Novel Method of Imaging Lysosomes in Living Human Mammary Epithelial Cells
title_full_unstemmed A Novel Method of Imaging Lysosomes in Living Human Mammary Epithelial Cells
title_short A Novel Method of Imaging Lysosomes in Living Human Mammary Epithelial Cells
title_sort novel method of imaging lysosomes in living human mammary epithelial cells
url https://doi.org/10.1162/15353500200302142
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