title: Dictyostelium extracellular vesicles containing hoechst 33342 transfer the dye into the nuclei of living cells: a fluorescence study.
abstract: Cells of the eukaryotic unicellular microorganism Dictyostelium discoideum are constitutively resistant to vital staining of their nuclei by the DNA-specific dye Hoechst 33342. By studying the mechanisms of this resistance, we evidenced that these cells expel vesicles containing the dye for detoxification (Tatischeff et al., Cell Mol Life Sci, 54: 476-87, 1998). The question to be addressed in the present work is the potential use of these extracellular vesicles as a biological drug delivery tool, using Hoechst 33342 as a model of a DNA-targeting drug. After cell growth with or without the dye, vesicles were prepared from the cell-free growth medium by differential centrifugation, giving rise to two types of vesicles. Negative staining electron microscopy showed their large heterogeneity in size. Using fluorescence techniques, data were obtained on the dye loading and its environment inside the vesicles. By UV video-microscopy, it was demonstrated that the dye-containing vesicles were able to deliver it into the nuclei of naive Dictyostelium cells, thus overcoming their constitutive resistance to the free dye. A vesicle-mediated dye-transfer into the nuclei of living human leukaemia multidrug resistant K562r cells was also observed.
authors: Laboratoire de Biophysique Moléculaire, Cellulaire et Tissulaire (BioMoCeTi), Université Pierre et Marie Curie, CNRS UMR 7033, Génopole Campus 1, 5 rue Henri Desbruères, Evry Cedex, France. tati@ccr.jussieu.fr
authors: Irène
authors: I
authors: Tatischeff
authors: Françoise
authors: F
authors: Lavialle
authors: Sophie
authors: S
authors: Pigaglio-Deshayes
authors: Christine
authors: C
authors: Péchoux-Longin
authors: Laurent
authors: L
authors: Chinsky
authors: Annette
authors: A
authors: Alfsen
mesh_terms: D000818:Animals; D001562:Benzimidazoles / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D022162:Cytoplasmic Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D004247:DNA / Q000378:metabolism*; D004023:Dictyostelium / Q000254:growth & development / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D008081:Liposomes; D008854:Microscopy, Electron; D018715:Microscopy, Video; D015394:Molecular Structure; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001562:Benzimidazoles; D005456:Fluorescent Dyes; D008081:Liposomes; D004247:DNA; C017807:bisbenzimide ethoxide trihydrochloride