title: The activity of G-ROS and the predominant role of Type II reaction in the photodynamic therapy using 9-hydroxypheophorbide-α for HeLa cell lines.
abstract: Photodynamic therapy (PDT) is a treatment modality that destroys the tumor. It activates the photosensitizer with the light of a specific wavelength, where the light is well absorbed by the photosensitizer, thus causing a fatal injury and thereby leading to a tumor necrosis. To date, a hematoporphyrin-derived photosensitizer has been widely used. It is disadvantageous, however, in that it causes a long-term photo-toxicity and has a poor selectivity for the tumor. This had led to the development of a chlorophyll-derived photosensitizer. We conducted this study to elucidate the mechanisms by which the activity of ROS is involved in the PDT using a novel type of chlorophyll-derived photosensitizer, 9-hydroxypheophorbide-α (9-HpbD-α), for the HeLa cell lines. Besides, we also attempted to determine which reaction plays a predominant role in the synthesis of ROS, either Type I reaction or Type II one, when both reactions are involved in the synthesis of ROS during the PDT using 9-HpbD-α. Our results showed not only that the activity of ROS is involved in the PDT using 9-HpbD-α in human uterine cervical cancer cell lines but also that the mechanisms of PDT are based on Type II reaction where the singlet oxygen is involved.
authors.affiliation: Medical Laser Research Center, Dankook University, Cheonan, Chungnam 330-714, Korea.
authors.forename: Jin-Chul
authors.initials: JC
authors.lastname: Ahn
authors.forename: Phil-Sang
authors.initials: PS
authors.lastname: Chung
mesh_terms: D002470:Cell Survival / Q000187:drug effects* / Q000528:radiation effects*; D002734:Chlorophyll / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006367:HeLa Cells; D006801:Humans; D008027:Light; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D026082:Singlet Oxygen / Q000378:metabolism*
chemical_list: C491791:9-hydroxypheophorbide alpha; D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; D002734:Chlorophyll; D026082:Singlet Oxygen