title: Intracellular boron accumulation in CHO-K1 cells using amino acid transport control.
abstract: BPA used in BNCT has a similar structure to some essential amino acids and is transported into tumor cells by amino acid transport systems. Previous study groups have tried various techniques of loading BPA to increase intracellular boron concentration. CHO-K1 cells demonstrate system L (LAT1) activity and are suitable for specifying the transport system of a neutral amino acid. In this study, we examined the intracellular accumulation of boron in CHO-K1 cells by amino acid transport control, which involves co-loading with L-type amino acid esters. Intracellular boron accumulation in CHO-K1 cells showed the greatest increased upon co-loading 1.0mM BPA, with 1.0mM l-Tyr-O-Et and incubating for 60min. This increase is caused by activation of a system L amino acid exchanger between BPA and l-Tyr. The amino acid esters are metabolized to amino acids by intracellular hydrolytic enzymes that increase the concentrations of intracellular amino acids and stimulate exchange transportation. We expect that this amino acid transport control will be useful for enhancing intracellular boron accumulation.
authors.affiliation: School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, Japan. Electronic address: e.sato@kitasato-u.ac.jp.
authors.forename: Eisuke
authors.initials: E
authors.lastname: Sato
authors.affiliation: Faculty of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Shikano
authors.affiliation: Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Ogura
authors.affiliation: Faculty of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Nakai
authors.affiliation: Faculty of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan.
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Yoshida
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Uemae
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Takada
authors.affiliation: Faculty of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Isobe
authors.affiliation: Faculty of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Matsumura
mesh_terms: D026905:Amino Acid Transport Systems / Q000493:pharmacokinetics; D000818:Animals; D001896:Boron Compounds / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D016754:Boron Neutron Capture Therapy / Q000379:methods*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004337:Drug Carriers / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D008657:Metabolic Clearance Rate; D010649:Phenylalanine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D014443:Tyrosine / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*
chemical_list: D026905:Amino Acid Transport Systems; D001896:Boron Compounds; D004337:Drug Carriers; D014443:Tyrosine; D010649:Phenylalanine; C033685:4-boronophenylalanine
keywords: Amino acid transport; Boron neutron capture therapy (BNCT); Chinese hamster ovary cells; l-p-Boronophenylalanine (BPA)