title: Structural alterations induced by photodynamic action of hematoporphyrin derivative (HpD) in plasma membrane of glioblastoma (U-87MG) cells: time dependent fluorescence spectroscopic study.
abstract: Photodynamic action of hematoporphyrin derivative (HpD) on the plasma membrane of human glioblastoma U-87MG cells was investigated using lipid and protein specific fluorescent probes trimethylammonium-1,6-diphenyl 1,3,5-hexatriene (TMA-DPH) and N-(1-pyrene)-maleimide (PM) respectively. Steady state anisotropy, decay time and time dependent anisotropy of these probes in U-87MG cells were measured. Light irradiation caused an increase in the steady state anisotropy of TMA-DPH in cells treated with HpD; however, no change in decay time was observed. Time dependent anisotropy measurements were performed and the data were analyzed using wobbling in cone model. A decrease in the rotational relaxation time (phi) as well as the cone angle (theta(c)) and an increase in the order parameter (S) of TMA-DPH were observed on photosensitization of cells. A decrease in the order parameter (S) of TMA-DPH were observed on photosensitization of cells. A decrease in the steady rate anisotropy and the rotational relaxation time (phi) of PM and enhancement in the lipid peroxidation were also observed. Our results show that the photodynamic action of HpD increases the order in the lipid bilayer and the mobility of the proteins in the plasma membrane of cells.
authors.affiliation: Department of Biophysics, National Institute of Mental Health and Neuro Science, Bangalore, India.
authors.forename: K
authors.initials: K
authors.lastname: Joshi
authors.forename: P G
authors.initials: PG
authors.lastname: Joshi
authors.forename: N B
authors.initials: NB
authors.lastname: Joshi
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002462:Cell Membrane / Q000187:drug effects; D005909:Glioblastoma / Q000188:drug therapy* / Q000473:pathology; D017324:Hematoporphyrin Derivative / Q000627:therapeutic use*; D006801:Humans; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D013050:Spectrometry, Fluorescence; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D017319:Photosensitizing Agents; D017324:Hematoporphyrin Derivative