IGF-I receptor gene activation enhanced the expression of monocarboxylic acid transporter 1 in hepatocarcinoma cells.
The present study aims to investigate the effect of IGF-I receptor (IGF-IR) gene activation on the expression of monocarboxylic acid transporters (MCTs) in hepatocarcinoma cells. In order to reflect malignant hepatoma, H4IIE cells (a rat hepatoma cell line) stably expressing IGF-IR (IGF-IR-H4IIE cells) have been established by retroviral infection and then the effect of IGF-IR gene up-regulation on the modulation of MCT expression was determined in IGF-IR-H4IIE cells. Immunoblot assay indicated that the expression level of MCT1 was 3.3-fold higher in IGF-IR-H4IIE cells compared to that in control cells, implying that IGF-IR signaling is coupled with the process of MCT1 expression. In contrast, the expression level of MCT2 was not affected by the IGF-IR activation, suggesting that MCT1 and MCT2 are regulated by the distinct type of signals. Furthermore, the cellular uptake of benzoic acid, a representative substrate of MCT1, was significantly (p<0.05) enhanced following the activation of IGF-IR via the pre-incubation with IGF-I (10 ng/ml). In conclusion, MCT1 expression was up-regulated in hepatocarcinoma cells and the IGF-IR signaling appeared to be coupled with the modulation of MCT1 expression.
Kang
Keon Wook
KW
College of Pharmacy, Chosun University, Susuk-dong, Gwangju, Republic of Korea.
Jin
Ming-Ji
MJ
Han
Hyo-Kyung
HK
D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D027501:Monocarboxylic Acid Transporters / Q000378:metabolism*; D005810:Multigene Family; D051381:Rats; D017526:Receptor, IGF Type 1 / Q000378:metabolism*; D027981:Symporters / Q000378:metabolism*; D015533:Transcriptional Activation; D000099233:Monocarboxylate Transport Protein 1
D027501:Monocarboxylic Acid Transporters; D017526:Receptor, IGF Type 1; D027981:Symporters; D000099233:Monocarboxylate Transport Protein 1; C091633:Slc16a7 protein, rat