Radioiodinated 4-iodo-l-meta-tyrosine, a system L selective artificial amino acid: molecular design and transport characterization in Chinese hamster ovary cells (CHO-K1 cells)

Intracellular boron accumulation in CHO-K1 cells using amino acid transport control

“…Both Tyr and Phe are taken into cells through system L (LAT1) but the intracellular accumulation of boron from loading L-Tyr-O-Et was higher than that from L-Phe-O-Et. Our data is similar to a previous report on artificial neutral amino acid (123I-3iodo-α-methyl-L-Tyrosine: IMT) uptake using CHO-K1 cells [5]. The driving force of system L (LAT1) is related to the amino acid concentration accumulated in cells in advance and the amino acid concentration gradient causes extra-and intracellular transport exchange.…”

“…Shikano et al reported that the uptake of extracellular IMT reaches a maximum from co-loading with L-Tyr-O-Et at 60 min in CHO-K1 cells and is maintained for 180 min [5]. In addition to this study, there are examinations of BPA uptake using co-loading with L-Tyr or L-DOPA [1, 3, and 6], which are taken into cells via system L (LAT1).…”

“…Previous studies [5] suggest that the uptake of synthetic neutral amino acids by CHO-K1 cells is increased by co-loading with L-type amino acid esters. In some previous reports on in vitro experiments using BPA [1,[6][7][8][9][10], cell-lines including 9L, C6, SCCVII, V79, and T98 were used for neutron irradiation experiments not associated with amino acid transport control.…”

“…One of the clinically capable 10 B compounds used in BNCT trials is L-p-boronophenylalanine (BPA), which has a structure similar to the essential amino acids tyrosine and phenylalanine and is transported into tumor cells by amino acid transport systems [1,2]. The transport of neutral amino acids relies on system L (LAT1; an amino acid exchanger) activity and Chinese hamster ovary cells (CHO-K1 cells) are reported to be suitable for specifying the transport system of a neutral amino acid [3][4][5].…”

Blood-Brain Barrier Molecular Trojan Horse Enables Imaging of Brain Uptake of Radioiodinated Recombinant Protein in the Rhesus Monkey

“…The Iodogen method incorporates the 125 I isotope on tyrosine residues of the protein, and the [ 125 I]-iodotyrosine formed by protein degradation may undergo further deiodination, which results in the formation of [ 125 I]-iodide. Iodotyrosine is a neutral amino acid that has high affinity for the large neutral amino acid transporter type 1, LAT1 . The LAT1 neutral amino acid transporter is highly expressed at the BBB, and provides for BBB penetration of circulating [ 125 I]-iodotyrosine.…”