Enhancement of 5-aminolevulinic acid-based fluorescence detection of side population-defined glioma stem cells by iron chelation.
Cancer stem cells (CSCs) are dominantly responsible for tumor progression and chemo/radio-resistance, resulting in tumor recurrence. 5-aminolevulinic acid (ALA) is metabolized to fluorescent protoporphyrin IX (PpIX) specifically in tumor cells, and therefore clinically used as a reagent for photodynamic diagnosis (PDD) and therapy (PDT) of cancers including gliomas. However, it remains to be clarified whether this method could be effective for CSC detection. Here, using flow cytometry-based analysis, we show that side population (SP)-defined C6 glioma CSCs (GSCs) displayed much less 5-ALA-derived PpIX fluorescence than non-GSCs. Among the C6 GSCs, cells with ultralow PpIX fluorescence exhibited dramatically higher tumorigenicity when transplanted into the immune-deficient mouse brain. We further demonstrated that the low PpIX accumulation in the C6 GSCs was enhanced by deferoxamine (DFO)-mediated iron chelation, not by reserpine-mediated inhibition of PpIX-effluxing ABCG2. Finally, we found that the expression level of the gene for heme oxygenase-1 (HO-1), a heme degradation enzyme, was high in C6 GSCs, which was further up-regulated when treated with 5-ALA. Our results provide important new insights into 5-ALA-based PDD of gliomas, particularly photodetection of SP-defined GSCs by iron chelation based on their ALA-PpIX-Heme metabolism.
Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 1138510, Japan.
Wenqian
W
Wang
Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 1138510, Japan.
Kouichi
K
Tabu
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B102, Nagatsuta-cho, Midori-ku, Yokohama, 2268501, Japan.
Yuichiro
Y
Hagiya
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B102, Nagatsuta-cho, Midori-ku, Yokohama, 2268501, Japan.
Yuta
Y
Sugiyama
Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 1138510, Japan.
Yasuhiro
Y
Kokubu
Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 1138510, Japan.
Yoshitaka
Y
Murota
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B102, Nagatsuta-cho, Midori-ku, Yokohama, 2268501, Japan.|School of Life Science and Technology, Tokyo Institute of Technology, 4259 B-47, Nagatsuta-cho, Midori-ku, Yokohama, 2268501, Japan.
Shun-Ichiro
SI
Ogura
Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 1138510, Japan.
Tetsuya
T
Taga
D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001711:Biotransformation; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D019070:Cell Lineage; D019295:Computational Biology; D003676:Deferoxamine / Q000494:pharmacology*; D005260:Female; D005456:Fluorescent Dyes / Q000032:analysis / Q000378:metabolism; D005910:Glioma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007502:Iron Chelating Agents / Q000494:pharmacology*; D007982:Levulinic Acids / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D016688:Mice, Inbred NOD; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D017319:Photosensitizing Agents / Q000378:metabolism* / Q000494:pharmacology; D011524:Protoporphyrins / Q000032:analysis / Q000378:metabolism; D051381:Rats; D012110:Reserpine / Q000494:pharmacology; D000622:Aminolevulinic Acid
D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D003676:Deferoxamine; D005456:Fluorescent Dyes; D051547:Heme Oxygenase-1; D007502:Iron Chelating Agents; D007982:Levulinic Acids; D017319:Photosensitizing Agents; D011524:Protoporphyrins; D012110:Reserpine; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX