Amino acid transport system L is differently expressed in human normal oral keratinocytes and human oral cancer cells.
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.
Yoon
Jung Hoon
JH
Oral Biology Research Institute, Chosun University College of Dentistry, Gwangju 501-759, Korea.
Kim
In Jin
IJ
Kim
Hyun
H
Kim
Heung-Joong
HJ
Jeong
Moon Jin
MJ
Ahn
Sang Gun
SG
Kim
Soo A
SA
Lee
Chong Heon
CH
Choi
Bong Kyu
BK
Kim
Jong-Keun
JK
Jung
Kyu Yong
KY
Lee
Seoul
S
Kanai
Yoshikatsu
Y
Endou
Hitoshi
H
Kim
Do Kyung
DK
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
D027062:Amino Acid Transport System L