title: Reactive oxygen species involved cancer cellular specific 5-aminolevulinic acid uptake in gastric epithelial cells.
abstract: Photodynamic therapy and photodynamic diagnosis using 5-aminolevulinic acid (ALA) are clinically useful for cancer treatments. Cancer cells have been reported that 5-aminolevulinic acid is incorporated via peptide transporter 1, which is one of the membrane transport proteins, and has been reported to be significantly expressed in various gastrointestinal cancer cells such as Caco-2. However, the mechanism of this protein expression has not been elucidated. Concentration of reactive oxygen species (ROS) is higher in cancer cells in comparison with that of normal cells. We have previously reported that ROS derived from mitochondria is likely related to invasions and proliferations of cancer cells. Since 5-aminolevulinic acid is the most important precursor of heme which is necessary protein for cellular proliferations, mitochondrial ROS (mitROS) may be also related to peptide transporter 1 expressions. In this study, we used a rat gastric mucosal cell line RGM1 and its cancer-like mutated cell line RGK1, and we clarified the ALA uptake mechanism and its relations between mitROS and peptide transporter 1 expression in RGK1. We also used our self-established stable clone of cell which over-expresses manganese superoxide dismutase, a mitROS scavenger. We studied differences of the photodynamic therapy effects in these cells after ALA administrations to clear the influence of mitROS.
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nohdai, Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Hiromu
authors.initials: H
authors.lastname: Ito
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nohdai, Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Tamura
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nohdai, Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Matsui
authors.affiliation: Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.
authors.forename: Hideyuki J
authors.initials: HJ
authors.lastname: Majima
authors.affiliation: Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.
authors.forename: Hiroko P
authors.initials: HP
authors.lastname: Indo
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nohdai, Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Ichinosuke
authors.initials: I
authors.lastname: Hyodo
keywords: aminolevulinic acid; gastric epithelial cell; mitROS; photodynamic therapy; porphyrin; reactive oxygen species