title: Development of bone-targeted catalase derivatives for inhibition of bone metastasis of tumor cells in mice.
abstract: Removal of hydrogen peroxide by delivering catalase to the vicinity of metastasizing tumor cells is a promising approach for inhibiting tumor metastasis. To inhibit bone metastasis, catalase was conjugated with 3,5-di(ethylamino-2,2-bisphosphono)benzoic acid (Bip), a derivative of bone-seeking bisphosphonates, polyethylene glycol (PEG), or both. Bip-conjugated catalase derivatives, that is, catalase-Bip and PEG-catalase-Bip, exhibited a higher affinity for bone matrix as compared with their counterparts without Bip. The tissue distribution of (111) In-labeled catalase derivatives indicated that the accumulation of radioactivity in bones was increased by conjugation of either Bip or PEG with catalase. An experimental bone metastasis model was developed by injecting male C57BL/6 mice with murine melanoma B16-BL6/Luc cells, which stably express firefly luciferase into left ventricle. Repeated injections of catalase to tumor-bearing mice had no significant effect on the number of melanoma cells in tibiae and femurs, whereas injections of catalase-Bip, PEG-catalase, or PEG-catalase-Bip significantly reduced the number. These results indicate that targeted delivery of catalase to the bones can be achieved by conjugating the enzyme with either Bip or PEG, and this delivery is effective in inhibiting the bone metastasis of tumor cells.
authors.affiliation: Department of Drug Delivery Research, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Zheng
authors.forename: Makiya
authors.initials: M
authors.lastname: Nishikawa
authors.forename: Mai
authors.initials: M
authors.lastname: Ikemura
authors.forename: Fumiyoshi
authors.initials: F
authors.lastname: Yamashita
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Hashida
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000517:prevention & control* / Q000556:secondary*; D002374:Catalase / Q000493:pharmacokinetics / Q000494:pharmacology*; D008297:Male; D008546:Melanoma, Experimental / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D014018:Tissue Distribution
chemical_list: D002374:Catalase