| Co-Investigator(Kenkyū-buntansha) |
TOKUYAMA Tsutomu Hamamatsu University School of Medicine, University Hospital, Associate Professor, 医学部附属病院, 講師 (90313957)
NAMBA Hiroki Hamamatsu University School of Medicine, Professor, 医学部, 教授 (60198405)
GAO Yun Hamamatsu University School of Medicine, Research Assistant (COE) (60402343)
西澤 茂 浜松医科大学, 医学部, 助教授 (40135257)
小出 昌代 浜松医科大学, 医学部, 助手 (40324347)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2005: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
Recently, it has been clarified that Wnt and sonic hedgehog signals are involved in medulloblastoma oncogenesis. Beside some other signals, such as Notch, which is known to also have roles in this phenomenon, these signals have cross talk with each other, the molecular mechanisms underlying the oncogenesis have not been fully understood. The other hand, with achievement of the Human Genome Project, human genomic database has been established and several methods, DNA microarray and SAGE, with which most of transcripts can be analyzed at once, have been developed. Moreover the concept of cancer stem cell has been suggested. The evidences of cancer stem cell theory and roles in proliferation, recurrence and/or metastasis were recently reported by some investigators.
We have analyzed and identified many developmentally regulated genes in medulloblastoma oncogenesis in human and rodents model animals. To clarify the molecular mechanisms underlying this phenomenon and the effect against the b
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iological properties of medulloblastoma cancer stem cell, we performed further analyses. FACS analyses using anti-CD133 mAb, as a cancer stem cell marker, in medulloblastoma cell lines, Daoy and D286MED. A few cells revealed positive immunoreactivity against the antibody. Furthermore, the expression profile was analyzed in CD133 positive cells enriched medulloblastoma cell line.
In silicon analyses using SAGE web site, medulloblastoma predominant developmentally regulated gene, zic1, showed reciprocal expression pattern against cmyc, which highly expressed in medulloblastoma tumor tissue of poor prognosis cases. Therefore we are analyzing role of myc in medulloblastoma oncogenesis using conditional deplete system of siRNA against myc. The stable transformant still have not acquired, this experiment is now on going.
We have been establishing stem cell therapy for malignant brain tumor, glioblastoma and medulloblastoma. In that precess, the immortalized cells were found in usual mesenchymal stem cell (MSC) culture. Some clones of immortalized MSC were isolated and developed, and the biological properties were analyzed. It was found that the ability of proliferation, mobility were increased, however, apoptosis and totipotency were decreased. The expression profile was also analyzed in this immortalized MSC. It was revealed that constituents of Wnt, Shh, Notch were up-regulated in immortalized MSC and the expression of stem cell marker, CD133 was dramatically decreased. These results were confirmed using quantitative RT-PCR, western analyses and immunohistochemistry. Allograft analyses, inoculation of the immortalized MSC into the rat brain, revealed that these cells could be engrafted whereas primary MSC could not survived. Less
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