title: Interaction dynamics of hypericin with low-density lipoproteins and U87-MG cells.
abstract: The natural photosensitizer hypericin exhibits potent properties for tumor diagnosis and photodynamic therapy. Fluorescent properties of hypericin along with various technical approaches have been used for dynamic studies of its interaction with low-density lipoprotein and U87 glioma cells. Evidences for hypericin release from low-density lipoprotein towards cells plasmatic membrane are addressed. Subsequent subcellular bulk flow redistribution leading to non-specific staining of intracellular membranes compartment were observed within cells. It was shown, that monomers of hypericin are the only redistributive forms. Increasing concentration of hypericin leads to the formation of non-fluorescent aggregates within low-density lipoprotein as well as within the U87 cells, and can preclude its photosensitizing activities. However, the aggregation process can only account for a part of the observed emission decrease. As shown by the excited state lifetime measurements, this fluorescence quenching actually results from a combination of aggregation process and energy transfer from monomers to aggregates. In all experiments, hydrophobic character of hypericin appears as the driving force of its redistribution process.
authors.affiliation: ANBioPhi, CNRS-FRE 3207, Pierre & Marie Curie University, Paris, France.
authors.forename: Veronika
authors.initials: V
authors.lastname: Huntosova
authors.forename: Luis
authors.initials: L
authors.lastname: Alvarez
authors.forename: Lenka
authors.initials: L
authors.lastname: Bryndzova
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Nadova
authors.forename: Daniel
authors.initials: D
authors.lastname: Jancura
authors.forename: Luboslava
authors.initials: L
authors.lastname: Buriankova
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Bonneau
authors.forename: Daniel
authors.initials: D
authors.lastname: Brault
authors.forename: Pavol
authors.initials: P
authors.lastname: Miskovsky
authors.forename: Franck
authors.initials: F
authors.lastname: Sureau
mesh_terms: D000873:Anthracenes; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D005453:Fluorescence; D005910:Glioma; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008077:Lipoproteins, LDL / Q000378:metabolism*; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000493:pharmacokinetics
chemical_list: D000873:Anthracenes; D008077:Lipoproteins, LDL; D017319:Photosensitizing Agents; D010569:Perylene; C004965:hypericin