title: Singlet oxygen and ROS in a new light: low-dose subcellular photodynamic treatment enhances proliferation at the single cell level.
abstract: Two-photon excitation of a sensitizer with a focused laser beam was used to create a spatially-localized subcellular population of reactive oxygen species, ROS, in single HeLa cells. The sensitizer used was protoporphyrin IX, PpIX, endogenously derived from 5-aminolevulinic acid delivered to the cells. Although we infer that singlet oxygen, O2(a(1)Δg), is one ROS produced upon irradiation of PpIX under these conditions, it is possible that the superoxide ion, O2(-˙), may also play a role in this system. With a "high" dose of PpIX-sensitized ROS, the expected death of the cell was observed. However, under "low dose" conditions, clear signs of cell proliferation were observed. The present results facilitate studies of ROS-mediated signalling in imaging-based single cell experiments.
authors: Center for Oxygen Microscopy and Imaging, Department of Chemistry, Aarhus University, DK-8000 Aarhus, Denmark. a.blazquez@chem.au.dk progilby@chem.au.dk.
authors: Alfonso
authors: A
authors: Blázquez-Castro
authors: Thomas
authors: T
authors: Breitenbach
authors: Peter R
authors: PR
authors: Ogilby
mesh_terms: D000622:Aminolevulinic Acid / Q000737:chemistry / Q000627:therapeutic use / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D006367:HeLa Cells; D006801:Humans; D007834:Lasers; D009369:Neoplasms / Q000188:drug therapy; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry / Q000627:therapeutic use / Q000633:toxicity; D011524:Protoporphyrins / Q000737:chemistry / Q000627:therapeutic use / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism*; D026082:Singlet Oxygen / Q000378:metabolism*
chemical_list: D017319:Photosensitizing Agents; D011524:Protoporphyrins; D017382:Reactive Oxygen Species; D026082:Singlet Oxygen; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX