title: MTT assays allow quick and reliable measurement of the response of human tumour cells to photodynamic therapy.
abstract: MCF-7 and HT-29 cell lines were selected as a reliable model to examine the possible parameters affecting the sensitivity of tumour cells to photodynamic therapy (PDT) using a dye-laser at 630 nm. The chemical composition of haematoporphyrin derivative (HPD) was determined by high-performance liquid chromatography (HPLC) analysis and was in agreement with reported values. MTT assays were performed to assess the time-dependency of PDT and the influence of the output power and light fluence. The results showed a maximal cytotoxicity 48 h after photoirradiation. The output power (1 or 2 W) did not significantly affect the cytotoxicity when the fluence was constant (20 J/cm2). However, an increase in fluence (10-40 J/cm2) led to a significant enhancement of cytotoxicity until maximal values were reached (30-40 J/cm2). A further increase in fluence (50 J/cm2) proved to induce a fall-off in cytotoxicity related to the intense photobleaching of HPD.
authors.affiliation: Unité de Recherche en Thérapie Photodynamique, Centre Régional de Transfusion Sanguine, Vandoeuvre-les-Nancy, France.
authors.forename: J L
authors.initials: JL
authors.lastname: Merlin
authors.forename: S
authors.initials: S
authors.lastname: Azzi
authors.forename: D
authors.initials: D
authors.lastname: Lignon
authors.forename: C
authors.initials: C
authors.lastname: Ramacci
authors.forename: N
authors.initials: N
authors.lastname: Zeghari
authors.forename: F
authors.initials: F
authors.lastname: Guillemin
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy*; D001943:Breast Neoplasms / Q000188:drug therapy*; D002851:Chromatography, High Pressure Liquid; D003110:Colonic Neoplasms / Q000188:drug therapy*; D005260:Female; D017324:Hematoporphyrin Derivative; D006415:Hematoporphyrins / Q000737:chemistry; D006801:Humans; D010778:Photochemotherapy / Q000379:methods*; D011838:Radiation-Sensitizing Agents / Q000737:chemistry; D012680:Sensitivity and Specificity; D013778:Tetrazolium Salts; D013844:Thiazoles; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D006415:Hematoporphyrins; D011838:Radiation-Sensitizing Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; D017324:Hematoporphyrin Derivative; C022616:thiazolyl blue