title: Oxidative alterations induced in vitro by the photodynamic reaction in doxorubicin-sensitive (LoVo) and -resistant (LoVoDX) colon adenocarcinoma cells.
abstract: In photodynamic therapy (PDT) a tumor-selective photosensitizer is administered and then activated by exposure to a light source of appropriate wavelength. Multidrug resistance (MDR) is largely caused by the drug efflux from the tumor cell by means of P-glycoprotein, resulting in reduced efficacy of the anticancer therapy. This study deals with photodynamic therapy with Photofrin (Ph) on colon cancer cell lines (doxorubicin-sensitive and -resistant). The cells were treated with 15 and 30 microg/mL Ph and then irradiated by a light dose of 3 or 6 J/cm(2) (632.8 nm). After irradiation the cells were incubated for 0, 3 or 18 h. Crucial factors of oxidative stress (thiobarbituric acid reactive substances [TBARS], protein damage, thiazolyl blue tetrazolium bromide [MTT] assay), changes in cytosolic superoxide dismutase (SOD1) activity after photodynamic reaction (PDR), and the intracellular accumulation of photosensitizers in the cells were examined. Moreover, the expressions of glutathione S-transferase (GST)-pi, a marker protein for photochemical toxicity, and secretory phospholipase A(2), a prognostic and diagnostic marker for colon cancers, were determined. After PDR, increases in SOD1 activity and the level of TBARS were observed in both cell lines. The level of protein-associated -SH groups decreased after PDR. Both cell lines demonstrated stronger GST-pi and PLA(2) expression after PDR, especially after 18 h of incubation. The increasing level of reactive oxygen species following the oxidation of sulfhydryl cell groups and lipid peroxidation influence the activity of many transporters and enzymes. The changes in SOD1 activity show that photodynamic action generates oxidative stress in treated cells. Our study presents that PDR caused oxidative alterations in both examined colon adenocarcinoma cell lines. However, the MDR cells reacted more slowly and all oxidative changes occurred in the delay.
authors.affiliation: Department of Medical Biochemistry, Medical University, Chalubinskiego 10, Poland. jkulbacka@gmail.com
authors.forename: Julita
authors.initials: J
authors.lastname: Kulbacka
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Chwilkowska
authors.forename: Julia
authors.initials: J
authors.lastname: Bar
authors.forename: Andrzej
authors.initials: A
authors.lastname: Pola
authors.forename: Teresa
authors.initials: T
authors.lastname: Banas
authors.forename: Andrzej
authors.initials: A
authors.lastname: Gamian
authors.forename: Jolanta
authors.initials: J
authors.lastname: Saczko
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D017323:Dihematoporphyrin Ether / Q000627:therapeutic use; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D051549:Glutathione S-Transferase pi / Q000378:metabolism; D054501:Group II Phospholipases A2 / Q000378:metabolism; D006414:Hematoporphyrin Photoradiation; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D018384:Oxidative Stress; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013482:Superoxide Dismutase / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D017319:Photosensitizing Agents; D011506:Proteins; C000606290:SOD1 protein, human; D013438:Sulfhydryl Compounds; D017392:Thiobarbituric Acid Reactive Substances; D004317:Doxorubicin; D017323:Dihematoporphyrin Ether; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi; D054501:Group II Phospholipases A2