Abstract

Amino acid transporters play an important role in supplying nutrients to normal and cancer cells for cell proliferation. System L is a major transport system responsible for the $Na^+$ -independent, large neutral amino acids including several essential amino acids. L-type amino acid transporter 1 (LAT1), an isoform of system L amino acid transporter, is highly expressed presumably to support their continuous growth and proliferation in malignant tumors. In the present study, we have examined the correlation between the expressions of amino acid transporter LAT1 mRNA and its subunit 4F2hc mRNA and the amount of L-leucine transport in various human cancer cell lines. Northern blot analysis have revealed that the 26 human cancer cell lines expressed LAT1 mRNA and 4F2hc mRNA. There were the differences for the levels of LAT1 and 4F2hc mRNA expressions in the 26 human cancer cell lines. The 26 human cancer cell lines transported the L-[$^{14}C$]leucine into the cells via amino acid transporter. In the 26 human cancer cell lines, a linear relationship was observed between the expression of amino acid transporter LAT1 mRNA and the amount of L-leucine transport. Little relationship was observed between the expression of 4F2hc mRNA and the amount of L-leucine transport, but the statistical significance of difference was not detected. These results indicate that the 26 human cancer cell lines express LAT1 mRNA and 4F2hc mRNA and there is the correlation between the expression of amino acid transporter LAT1 mRNA and the amount of L-leucine transport. In addition, specific inhibition of LAT1 in cancer cells will be a new rationale for anti-cancer therapy.

Keywords

• L-type amino acid transporter 1 (LAT1);
• essential amino acids;
• growth inhibition;
• anti-cancer therapy

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References

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