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Boronophenylalanine, a boron delivery agent for boron neutron capture therapy, is transported by ATB0,+, LAT1 and LAT2.

Wongthai P, Hagiwara K, Miyoshi Y, Wiriyasermkul P, Wei L, Ohgaki R, Kato I, Hamase K, Nagamori S, Kanai Y - Cancer Sci. (2015)

Bottom Line: Among aromatic amino acid transporters, ATB(0,+), LAT1 and LAT2 were found to transport BPA with Km values of 137.4 ± 11.7, 20.3 ± 0.8 and 88.3 ± 5.6 μM, respectively.ATB(0,+), LAT1 and LAT2 transport BPA at affinities comparable with their endogenous substrates, suggesting that they could mediate effective BPA uptake in vivo.ATB(0,+), as well as LAT1, could contribute significantly to the tumor accumulation of BPA at clinical dose.

View Article: PubMed Central - PubMed

Affiliation: Division of Bio-system Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Japan.

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Related in: MedlinePlus

Transporter expression and p-boronophenylalanine (BPA) uptake in cancer cell lines. (a) Expression level of LAT1 was analyzed by western blotting using crude membrane fraction. The cell lines were ordered in increasing LAT1 amounts. Na+/K+ ATPase was used as loading control. (b) Similarly, the expression of ATB0,+ was analyzed. ATB0,+ was expressed in MCF-7 cells, to a lesser degree in T3M4 cells, and not detected in the other cell lines. (c) Uptake of BPA in cell lines was measured for 5 min in the presence or absence of Na+. The presence of Na+ did not significantly affect the BPA uptakes in the cell lines. A representative result was shown with the mean ± SEM (n = 4).
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fig05: Transporter expression and p-boronophenylalanine (BPA) uptake in cancer cell lines. (a) Expression level of LAT1 was analyzed by western blotting using crude membrane fraction. The cell lines were ordered in increasing LAT1 amounts. Na+/K+ ATPase was used as loading control. (b) Similarly, the expression of ATB0,+ was analyzed. ATB0,+ was expressed in MCF-7 cells, to a lesser degree in T3M4 cells, and not detected in the other cell lines. (c) Uptake of BPA in cell lines was measured for 5 min in the presence or absence of Na+. The presence of Na+ did not significantly affect the BPA uptakes in the cell lines. A representative result was shown with the mean ± SEM (n = 4).

Mentions: LAT2 expression is associated with normal tissues, whereas LAT1 and ATB0,+ are known for their relevance to malignant tumors.6,9,20 To assess the contribution of LAT1 and ATB0,+ in BPA uptake, uptake rates were measured in cancer cell lines with various expression levels of LAT1 and ATB0,+. The LAT1 protein amounts were compared in Western blot analysis: low in FLC-4, medium in MCF-7 and MIA PaCa-2, and high in HeLa S3 and T3M4 cells (Fig.5a). In contrast, ATB0,+ protein was strongly detected in MCF-7 and also weakly in T3M4 cells, but not in the other cell lines (Fig.5b). The BPA uptake rates were proportional to the LAT1 protein levels (Fig.5a,c). We examined the Na+-dependence of BPA uptake, because ATB0,+ is Na+-dependent whereas LAT1 is not. There were no significant differences in the uptakes at 100 μM BPA between Na+-free and normal Na+ conditions (Fig.5c).


Boronophenylalanine, a boron delivery agent for boron neutron capture therapy, is transported by ATB0,+, LAT1 and LAT2.

Wongthai P, Hagiwara K, Miyoshi Y, Wiriyasermkul P, Wei L, Ohgaki R, Kato I, Hamase K, Nagamori S, Kanai Y - Cancer Sci. (2015)

Transporter expression and p-boronophenylalanine (BPA) uptake in cancer cell lines. (a) Expression level of LAT1 was analyzed by western blotting using crude membrane fraction. The cell lines were ordered in increasing LAT1 amounts. Na+/K+ ATPase was used as loading control. (b) Similarly, the expression of ATB0,+ was analyzed. ATB0,+ was expressed in MCF-7 cells, to a lesser degree in T3M4 cells, and not detected in the other cell lines. (c) Uptake of BPA in cell lines was measured for 5 min in the presence or absence of Na+. The presence of Na+ did not significantly affect the BPA uptakes in the cell lines. A representative result was shown with the mean ± SEM (n = 4).
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4376436&req=5

fig05: Transporter expression and p-boronophenylalanine (BPA) uptake in cancer cell lines. (a) Expression level of LAT1 was analyzed by western blotting using crude membrane fraction. The cell lines were ordered in increasing LAT1 amounts. Na+/K+ ATPase was used as loading control. (b) Similarly, the expression of ATB0,+ was analyzed. ATB0,+ was expressed in MCF-7 cells, to a lesser degree in T3M4 cells, and not detected in the other cell lines. (c) Uptake of BPA in cell lines was measured for 5 min in the presence or absence of Na+. The presence of Na+ did not significantly affect the BPA uptakes in the cell lines. A representative result was shown with the mean ± SEM (n = 4).
Mentions: LAT2 expression is associated with normal tissues, whereas LAT1 and ATB0,+ are known for their relevance to malignant tumors.6,9,20 To assess the contribution of LAT1 and ATB0,+ in BPA uptake, uptake rates were measured in cancer cell lines with various expression levels of LAT1 and ATB0,+. The LAT1 protein amounts were compared in Western blot analysis: low in FLC-4, medium in MCF-7 and MIA PaCa-2, and high in HeLa S3 and T3M4 cells (Fig.5a). In contrast, ATB0,+ protein was strongly detected in MCF-7 and also weakly in T3M4 cells, but not in the other cell lines (Fig.5b). The BPA uptake rates were proportional to the LAT1 protein levels (Fig.5a,c). We examined the Na+-dependence of BPA uptake, because ATB0,+ is Na+-dependent whereas LAT1 is not. There were no significant differences in the uptakes at 100 μM BPA between Na+-free and normal Na+ conditions (Fig.5c).

Bottom Line: Among aromatic amino acid transporters, ATB(0,+), LAT1 and LAT2 were found to transport BPA with Km values of 137.4 ± 11.7, 20.3 ± 0.8 and 88.3 ± 5.6 μM, respectively.ATB(0,+), LAT1 and LAT2 transport BPA at affinities comparable with their endogenous substrates, suggesting that they could mediate effective BPA uptake in vivo.ATB(0,+), as well as LAT1, could contribute significantly to the tumor accumulation of BPA at clinical dose.

View Article: PubMed Central - PubMed

Affiliation: Division of Bio-system Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Japan.

Show MeSH
Related in: MedlinePlus