Ultrastructural localization of daunomycin in multidrug-resistant cultured cells with modulation of the multidrug transporterAV Rutherford and MC Willingham Ultrastructural Cytochemistry Section, National Cancer Institute, National Institutes of Health, Bethesda, Maryland. We localized the chemotherapeutic drug daunomycin inside cultured cells by taking advantage of its inherent fluorescence. Multidrug-resistant cultured cells, in which the accumulation of daunomycin can be reversibly controlled with verapamil to block the multidrug transporter, were incubated in daunomycin and verapamil and the accumulated daunomycin was visualized with epifluorescence optics. After fixation under a variety of different conditions to make cells permeable to diaminobenzidine (DAB), the internal daunomycin was illuminated under the fluorescence microscope in the presence of DAB. Photooxidation of DAB in sites of fluorescing daunomycin (photoconversion) resulted in intracellular deposition of oxidized DAB product. These sites were then visualized by transmission electron microscopy. In cells in which the multidrug transporter was inhibited by verapamil, daunomycin was localized in the nucleus of cells by mild fixation conditions such as formaldehyde. Increasing amounts of glutaraldehyde in the fixative caused apparent quenching of the nuclear fluorescence but still allowed fluorescence to occur in other cell organelles, which were then well preserved. Daunomycin was found in the nuclear envelope, the endoplasmic reticulum, and in lysosomes in cells in which the multidrug transporter was inhibited. Lysosomal accumulation has been previously described and was expected because of the known accumulation of positively charged molecules in organelles with low pH. However, the accumulation of daunomycin in the nuclear envelope and endoplasmic reticulum has not been previously observed. These results clearly demonstrate the utility of fluorescence photoconversion methodology for the high-resolution ultrastructural localization of fluorescent materials.
Volume 41,
Issue 10,
pp. 1573-1577,
10/01/1993
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V. Stierle, M. Duca, L. Halby, C. Senamaud-Beaufort, M. L. Capobianco, A. Laigle, B. Jolles, and P. B. Arimondo Targeting MDR1 Gene: Synthesis and Cellular Study of Modified Daunomycin-Triplex-Forming Oligonucleotide Conjugates Able to Inhibit Gene Expression in Resistant Cell Lines Mol. Pharmacol., May 1, 2008; 73(5): 1568 - 1577. [Abstract] [Full Text] [PDF] |
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K. Fujiwara, H. Takatsu, and K. Tsukamoto Immunocytochemistry for Drugs Containing an Aliphatic Primary Amino Group in the Molecule, Anticancer Antibiotic Daunomycin as a Model J. Histochem. Cytochem., April 1, 2005; 53(4): 467 - 474. [Abstract] [Full Text] [PDF] |
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G. M. Carbone, E. McGuffie, S. Napoli, C. E. Flanagan, C. Dembech, U. Negri, F. Arcamone, M. L. Capobianco, and C. V. Catapano DNA binding and antigene activity of a daunomycin-conjugated triplex-forming oligonucleotide targeting the P2 promoter of the human c-myc gene Nucleic Acids Res., April 30, 2004; 32(8): 2396 - 2410. [Abstract] [Full Text] [PDF] |
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G. Decorti, I. Peloso, D. Favarin, F. B. Klugmann, L. Candussio, E. Crivellato, F. Mallardi, and L. Baldini Handling of Doxorubicin by the LLC-PK1 Kidney Epithelial Cell Line J. Pharmacol. Exp. Ther., July 1, 1998; 286(1): 525 - 530. [Abstract] [Full Text] |
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N. Altan, Y. Chen, M. Schindler, and S. M. Simon Defective Acidification in Human Breast Tumor Cells and Implications for Chemotherapy J. Exp. Med., May 18, 1998; 187(10): 1583 - 1598. [Abstract] [Full Text] [PDF] |
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