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The Korean Journal of Pathology 1996;30(3): 210-217.
Alteration of Phospholipase C Activity in Human Gastric Cancer Tissues.
Young Ok Kim, Moo Youn Cho, Sung Do Lee, Sung Sook Kim, Pann Ghill Suh, Man Ha Huh
1Department of Pathology, Kosin University Medical Center, Korea.
2Department of Biochemistry, Kosin University Medical Center, Korea.
3Department of General Surgery, Kosin University Medical Center, Korea.
4Department of Pathology, Ewha Women's University Hospital, Korea.
5Department of Life Science, Pohang Institute of Science and Technology, Korea.
Phospholipase C (PLC) plays a pivotal role in transmembrane signal transduction pathway for cellular proliferation differentiation and growth. Thus far, there have been few reports in which PLC activity was investigated in human malignant neoplastic tissues. In the present study, we evaluated PLC activity in 23 human gastric cancer tissues and normal mucosal tissues to investigate whether alteration of PLC activity is associated with gastric cancer. The amount of [14C] diacylglycerol, one of the earliest products of inositol phospholipid hydrolysis by PLC, was measured by thin layer chromatography. Also, expression of PLC-gamma1, which is one of the most important PLC isozymes,was examined by immunohistochemistry using specific monoclonal antibody directed against PLC-gamma1. The results are summarized as follows. PLC activity in all 23 gastric cancer tissues (1.35+/-1.04 units/mg of protein) was significantly higher than normal mucosal tissues (0.28+/-0.21 units/mg of protein) (P<0.001). PLC activity in gastric cancer tissues was not correlated with histologic grade (P>0.05). PLC-gamma1 immunoreactivity was detected in all of 23 cases studied. The intensity and extent of PLC-gamma1 immunoreactivity was not correlated with PLC enzyme activity, although stronger intensity was demonstrated in malignant cells in comparison to normal gland epithelial cells. The present study provides the first evidence of significant elevation of PLC activity in human stomach cancer tissues. Our results strongly suggest that PLC might be involved in tumorigenesis and/or progression(uncontrolled continuous cycling of cells) of human gastric cancer. Further studies are needed to elucidate the role of elevated PLC activity in cancer tissues.
Key Words: Phospholipase C; Diacylglycerol; Phospholipase C-gamma1; Human gastric cancer