| Project/Area Number |
11671590
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Urology
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| Research Institution | HYOGO COLLEGE OF MEDICINE |
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Principal Investigator |
TAMAOKI Tomoko HYOGO COLLEGE OF MEDICINE, HYOGO COLLEGE OF MEDICINE, ASSOCIATE PROFESSOR (10172868)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMA Hiroki 兵庫医科大学, HYOGO COLLEGE OF MECDICINE, PROFESSOR (90104257)
MORI Yoshinori 兵庫医科大学, HYGO COLLEGE OF MECDICINE, ASSOCIATE PROFESSOR (80131598)
FURUYAMA Jun-Ichi 兵庫医科大学, HYGO COLLEGE OF MECDICINE, PROFESSOR (30068431)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1999: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | prostate cancer / androgen insensitivity / resistance for therapy / cell death (apoptosis) / cell differentiation / cdk inhibitor / control of gene expression / Historic deacetylase inhibitor / ヒストンデアセチラーゼ / Sp1 / 分化誘導 / アポトーシス / cdk inhibitor / レチノイン酸 / sodium butyrate |
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| Research Abstract |
Effects of inhibitors of histone deacetylase (HDAC), sodium butyrate (SB) and FR101228 (FR), on the growth of prostate cancer cells were analyzed. SB at 0.5-3 mM and FR at 1-3ng/ml significantly inhibited cell growth with induction of apoptosis in 3 to 5 days. These concentrations of the HDAC inhibitors were less than one half of those exhibiting similar effects on hepatoma cells, indicating high sensitivity of prostate cancer cells to HDAC inhibitors. The effective concentration of FR was less than 1/106 that of SB. FR, therefore, is much more suitable for clinical application. Comparison of the cytotoxicity of prostate cancer cells induced by HDAC inhibitors in terms of malignancy indices, dependency or independency on androgen and the presence or absence of RB proteins, showed little difference.
To examine the effect of the HDAC inhibitors on cellular differentiation, SB was injected into tumors grown from human squamous carcinoma cells inoculated into nude mice subcutaneously. We fo
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und keratinization of the tumor, indicating effectiveness of the HDAC inhibitors in vivo. Direct injection of FR into prostate tumors growing in nude mice subcutaneously did not reduce the size of the tumors but inhibited tumor growth. Administration of FR at a concentration 1,000 times higher than that used in vitro only resulted in body weight less.
We reported earlier that SB induces the expression of one of cdk inhibitors, p21/waf1/cip1, markedly in hepatoma cells. The same effect was observed with FR at the above concentration. We also analyzed whether induction of expression of p21 was dependent on the p53 status, and found that p21 expression was significantly induced by FR treatment even in cells with mutant p53. Similar results were obtained with prostate cancer cells with or without dependency on androgen, indicating that no correlation exists between the malignancy index and the effect of HDAC inhibitors.
Mechanisms of induction of p21 by FR was analyzed by transfection with the luciferase reporter gene linked to 2 kb of the p21 5'-flanking sequence using hepatoma cells, because transfection efficiency of prostate cancer cells were relatively low. FR was found to stimulate reporter activity at low concentrations which did not induce apoptosis. A region from -200 to -60 nucleotides was essential for mediating transcriptional stimulation by FR. Expression of the reporter gene was increased by repeating this region tandemly. Such constructs may be of use as a vector for gene therapy aimed at inducing cell death even at a low concentration of HDAC inhibitors. Less
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