A study on the regulation of translocation of glucose transporters during hepatocarcinogenesis induced by 3'-Me DAB.
10.3349/ymj.1990.31.4.315
- Author:
Yoon Soo KIM
1
;
Eun Mee PAIK
;
Myung Shik LEE
;
Kyung Sup KIM
;
Kyung Ja CHAI
;
Yong Ho AHN
Author Information
1. Department of Biochemistry, Yonsei University College of Medicine, Seoul, Korea.
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
Western blot;
plasma membrane;
low density microsomal fractions;
glucose transporter;
hepatocarcinogenesis;
3'-Me DAB;
translocation
- MeSH:
Animal;
Blotting, Western;
Cell Membrane/chemistry;
Cytochalasin B/metabolism;
Glucose/*analysis;
Liver Neoplasms, Experimental/*metabolism;
Male;
Methyldimethylaminoazobenzene;
Microsomes, Liver/*chemistry;
Monosaccharide Transport Proteins/*analysis;
Rats;
Support, Non-U.S. Gov't
- From:Yonsei Medical Journal
1990;31(4):315-324
- CountryRepublic of Korea
- Language:English
-
Abstract:
The mechanism of glucose transported (GT) expression on the plasma membranes of hepatoma cells in rats induced by 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) was studied. Cytochalasin B binding to plasma membrane fractions from control and 3'-MeDAB group in the absence of cold cytochalasin B showed 9,825 +/- 925 and 30,165 +/- 625 dpm/mg membrane protein. Scatchard plot analysis showed that the GTs present on the plasma membrane fractions in control and 3'-Me DAB groups were 5.0 and 16.0 pmol/mg membrane protein and their Kd values were 151 and 157 nM, respectively. These results suggest that the numbers of GTs in plasma membrane were increased in the 3'-Me DAB group compared to the control group. In contrast, the amounts of GTs in low density microsomal (LDM) fractions measured by a photoaffinity labeling technique using [3H]-cytochalasin B were 31,207 and 11,702 dpm/mg protein in the control and 3'-Me DAB group, respectively. These results suggest that GTs were translocated from LDM to plasma membranes during carcinogenesis. To confirm these results by an independent method 10% SDS-polyacrylamide gel electrophoresis was carried out. Gel slice No. 13 corresponding to MW of 45 kDa from plasma membrane fractions showed increased radioactivities in the 3'-Me DAB group compared to the control group. However, LDM fractions of the 3'-Me DAB group showed decreased radioactivities compared to the control group. Western blot analysis using anti-human RBC GT antibody present in the plasma membranes and LDM fractions from control and 3'-Me DAB groups did not show any significant difference, indicating low cross-reactivity between them. These results indicate that increased glucose transport seems to be more likely due to reciprocal redistribution of GTs between plasma membrane and LDM fractions.
