title: Cellular inhibition of microtubule assembly by photoactivated sulphonated meso-tetraphenylporphines.
abstract: This work relates to studies on modes of phototoxicity by sulphonated mesotetraphenylporphines on cultured cells. Toxicity appears to be related to inhibition of microtubule function. Treatment of human cervix carcinoma cells of the line NHIK 3025 incubated for 18 h with meso-tetraphenylporphine sulphonates (TPPSn where n = 2a, 2o or 4) and exposed to light, inhibits multiplication for the first hours after light exposure, a significant fraction of the cells accumulating in mitosis. The maximal number of cells in mitosis after treatment (approximately 20%) is dependent on the fluence but is similar for all three photosensitizers. For the first hours after treatment the mitotic cells were always mainly in metaphase; mainly seen as c-metaphases and three-group metaphases. During this time anaphase and telophase cells were absent or greatly reduced in number. Indirect immunofluorescence staining of beta-tubulin showed that the spindle apparatus of mitotic cells was perturbed in all cases. Results are presented which indicate that photoactivation of TPPSn located on the plasma membrane destroys microtubules in interphase cells and leads to arrest of the cells in mitosis. The localization of the dye which sensitizes the photoinduced perturbation of microtubules is further discussed.
authors.affiliation: Institute for Cancer Research, Department of Biophysics, Montebello, Oslo, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Berg
authors.forename: J
authors.initials: J
authors.lastname: Moan
authors.forename: J C
authors.initials: JC
authors.lastname: Bommer
authors.forename: J W
authors.initials: JW
authors.lastname: Winkelman
mesh_terms: D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D008870:Microtubules / Q000187:drug effects*; D008940:Mitotic Index / Q000187:drug effects; D010778:Photochemotherapy / Q000009:adverse effects*; D011166:Porphyrins
chemical_list: D011166:Porphyrins; C016136:tetraphenylporphine sulfonate