| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
Apoptosis was induced in human glioma cell lines by exposure to calphostin C, a specific inhibitor of protein kinase C.During induction of apoptosis, the formation of actin stress fiber was observed under an Olympus AX-80 fluorescence microscope. To elucidate a signaling pathway to form actin stress fiber in calphostin C-induced apoptosis, glioma cells were pretreated with Wortmannin (MLC inhibitor), Y-27632 (Rho kinase inhibitor), or calpeptin (calpine inhibitor). The formation of actin stress fiber was suppressed in glioma cells pretreated with Y-27632.
SAPK/JNK and p38 kinase have been proposed to mediate apoptosis. To clarify the roles of SAPK/JNK and p38 kinase in calphostin-induced apoptosis, , SAPK/JNK and p38 kinase were inhibited by transfection of dominant negative SAPK/JNK using FuGENE6, and by SB203580 (specific inhibitor of p38 kinase), respectively. Inhibition of SAPK/JNK or p38 kinase was ascertained by immunoblot analysis using anti-phosphospecific antibody. Calphostin C-induced apoptotic nuclear damage decreased markedly by dominant negative SAPK/JNK or SB203580. However, no synergistic inhibitory effect on calphostin C-induced cell death was proved by dominant negative SAPK/JNK combined with SB203580.
Phosphorylation of MLC was speculated to associate with the formation of aciton stress fiber. MLC was quantifd in surgical specimen of human glioma by immunoblot analysis. There was no significant correlation between the amount of MLC and the grade of glioma. The phospholylation of MLC was measured using urea-gel electrophoresis, but not yet detected sufficiently till now.
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