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Original Articles
- Alteration of Phospholipase C Activity in Human Gastric Cancer Tissues.
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Young Ok Kim, Moo Youn Cho, Sung Do Lee, Sung Sook Kim, Pann Ghill Suh, Man Ha Huh
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Korean J Pathol. 1996;30(3):210-217.
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Abstract
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- 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.
- Expression of Phospholipase C Isozymes in Radiation-Induced Tissue Damage and Subsequent Regeneration of Murine Small Intestine.
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Sung Sook Kim, Yeong Ju Woo, Ju Ryung Huh, Jung Hyun Ryu, Kyung Ja Lee, Jung Sik Lee, Pann Ghill Suh
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Korean J Pathol. 1998;32(3):155-161.
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Abstract
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- Phospholipase C (PLC) isozymes play significant roles in transmembrane signal transduction. PLC- 1 is one of the key regulatory enzymes in signal transduction for cellular proliferation and differentiation. The exact mechanisms of this signal transduction of tissue damage and subsequent regeneration, however, were not clearly documented. This study was planned to determine the biological significance of PLC isozymes following irradiation in rat small intestine. Sprague-Dawley rats were irradiated to the entire body by a single dose of 8 Gy. The rats were divided into 5 groups according to the sacrifice days after irradiation.
The expression of PLCs in each group was examined by the immunohistochemistry and immunoblotting. The histologic findings were observed using hematoxylin and eosin staining.
The regenerative activity, which was estimated by mitotic count and proliferatin cell nuclear antigen (PCNA) immunostaining, was highest in Group III (5th day after irradiation). By the immunohistochemistry, the expression of PLC- 1 was higher in Group III and Group II (3rd day after irradiation), and was found in the regenerative zone of the mucosa. The expression of PLC- 1 was highest in Group I (1st day after irradiation) and was dominantly in the damaged surface epithelium. The immunostaining of PLC- 1 was negative in all groups. The results of the immunoblotting study was compatible to that of the immunohistochemical study. Group II and III showed positive bands for PLC- 1, and group I and II for PLC- 1. These results suggest that PLC- 1 plays a significant role in mucosal regeneration following irradiation. PLC- 1 may play a role in radiation - induced mucosal damage.
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