구강 편평세포암종 KB 세포에서 아미노산 수송계 L의 특성 Characterization of the system L amino acid transporter in KB human oral epidermoid carcinoma cells
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It has been said that amino acid transporters play an important role in supplying nutrition to normal and cancer cells and for cell proliferation. System L is a major nutrient transport system responsible for the Na+-independent transport of large neutral amino acids including several essential amino acids. In malignant tumors, a system L transporter L-type amino acid transporter 1(LAT1) is up-regulated to support tumor cell growth. In the present study, we have examined the function of LAT1 and its expression in the KB human oral epidermoid carcinoma cells. RT-PCR, western blot analysis and immunohistochemical analysis have revealed that KB cells express LAT1 in the plasma membrane together with its associating protein 4F2hc, whereas KB cells do not express the other system L isoform LAT2. The uptake of L-[14C]leucine by KB cells is Na+-independent and almost completely inhibited by system L selective inhibitor BCH. The profiles of the inhibition of L-[14C]leucine uptake by amino acids in the KB cells are comparable with those for the LAT1 expressed in Xenopus oocytes. The majority of L-[14C]leucine uptake is, therefore, mediated by LAT1 in the KB cells. These results suggest that the uptakes of neutral amino acids including several essential amino acids in the KB oral epidermoid carcinoma cells mediated by LAT1. In addition, specific inhibition of LAT1 by such agents as BCH in human oral squamous cell carcinomas will be a new rationale for anti-cancer therapy.
II. 재료 및 방법
1. 실험재료 및 세포
2. Total RNA 추출과 역전사-중합효소연쇄반응(RT-PCR)
3. Western blot analysis
4. 면역조직화학염색
5. Uptake 실험
III. 결 과
1. KB 세포에서 아미노산 transporter LAT1,LAT2 및 4F2hc의 발현
2. KB 세포에서 L-[14C]leucine의 수송특성
IV. 고 찰
V. 결 론
VI. 감사의 글
참고 문헌