title: Amino acid transport system L is differently expressed in human normal oral keratinocytes and human oral cancer cells.
abstract: Previously, we reported the expression and function of system L amino acid transporter in KB human oral epidermoid carcinoma cells. In the present study, therefore, we investigated the expression and function of system L amino acid transporter in human normal oral keratinocytes (HNOK) and compared the expressions and functions of system L amino acid transporters in HNOK and KB cells. The HNOK expressed L-type amino acid transporter 1 (LAT1) and L-type amino acid transporter 2 (LAT2) with their subunit 4F2hc in the plasma membrane but the expression of LAT1 was very weak, which is in contrast to the KB cells expressing LAT1 but not LAT2 with the 4F2hc in the plasma membrane. The [14C] L-leucine uptake by HNOK, as well as KB cells, was inhibited by the system L selective inhibitor BCH. The majority of [14C] L-leucine uptake was, therefore, mainly mediated by LAT2 in the HNOK and by LAT1 in the KB cells. These results suggest that the transport of neutral amino acids including several essential amino acids into the HNOK and KB cells are mainly mediated by LAT2 and LAT1, respectively. The specific inhibition of LAT1 in oral cancer cells could be a new rationale for anti-cancer therapy.
authors.affiliation: Oral Biology Research Institute, Chosun University College of Dentistry, Gwangju 501-759, Korea.
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Yoon
authors.forename: In Jin
authors.initials: IJ
authors.lastname: Kim
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
authors.forename: Heung-Joong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Moon Jin
authors.initials: MJ
authors.lastname: Jeong
authors.forename: Sang Gun
authors.initials: SG
authors.lastname: Ahn
authors.forename: Soo A
authors.initials: SA
authors.lastname: Kim
authors.forename: Chong Heon
authors.initials: CH
authors.lastname: Lee
authors.forename: Bong Kyu
authors.initials: BK
authors.lastname: Choi
authors.forename: Jong-Keun
authors.initials: JK
authors.lastname: Kim
authors.forename: Kyu Yong
authors.initials: KY
authors.lastname: Jung
authors.forename: Seoul
authors.initials: S
authors.lastname: Lee
authors.forename: Yoshikatsu
authors.initials: Y
authors.lastname: Kanai
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Endou
authors.forename: Do Kyung
authors.initials: DK
authors.lastname: Kim
mesh_terms: D027062:Amino Acid Transport System L / Q000096:biosynthesis* / Q000502:physiology*; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology*; D020869:Gene Expression Profiling; D006801:Humans; D015603:Keratinocytes / Q000502:physiology*; D009062:Mouth Neoplasms / Q000235:genetics* / Q000473:pathology*; D016133:Polymerase Chain Reaction
chemical_list: D027062:Amino Acid Transport System L