1999 Fiscal Year Annual Research Report

テロメラーゼ機能の解析と細胞の不死化・癌化への役割

Research Project

Project/Area Number	10470483
Research Institution	Hiroshima University
Principal Investigator	井出利憲広島大学, 医学部, 教授 (60012746)
Keywords	テロメラーゼ / TERT / SV40-T抗原 / 不死化 / 癌診断
Research Abstract	ヒト正常線維芽細胞は、テロメラーゼの触媒ユニット遺伝子(hTERT)の導入によってテロメラーゼを発現し、テメロアサイズが延長し、分裂寿命が延長したにもかかわらず、不死化するものは得られなかった。テロメラーゼのほかに不死化に必要な遺伝子機能を探る目的で、DNA型癌ウイルスSV40の癌遺伝子であるT抗原遺伝子を導入した線維芽細胞(有限分裂寿命)にhTERTを導入した。薬剤選択によって、hTERTが導入された細胞を選択しクローニングしたといころ、ほぼすべてのクローンがテロメラーゼを発現し、テロメアサイズが延長し、不死化した。すなわち、ヒト線維芽細胞は、T抗原遺伝子とhTERT遺伝子の両方があれば不死化することが明らかになった。これらの細胞は、温度感受性変異を持つT抗原遺伝子を導入してあるので、非許容温度によりT抗原を失活させたところ、延命中の細胞は増殖を停止したにもかかわらず、不死化後の細胞は全く増殖が低下しなかった。T抗原による癌細胞表現型(パイルアップ増殖など)は非許容温度では失われた。不死化するためにはT抗原とテロメラーゼの両方の機能が必要であるが、不死化が成立した後はT抗原の機能は不要であるか、または非許容温度でも残存するごく一部の機能があればよいかのいずれかである考えられる。これを明らかにするために、現在、hTERTを導入した有限分裂寿命の線維芽細胞に、T抗原機能の内のごく一部を保持するt抗原遺伝子を導入し、延命・不死化の有無を検討している。また、前年度に確立した、テロメラーゼ活性の高感度・定量的測定法により,早々期の癌診断への可能性については、肝癌、肝前癌病変、慢性肝炎・肝硬変および正常肝でのテロメラーゼ活性の発現と,テロメラーゼの各サブユニットがどうのように発現するかを調べた。特にテロメラーゼ活性の低い前癌病変と慢性肝炎や肝硬変における、高感度で定量的な活性測定により、前癌病変の約半数に極めて低活性ながら、非癌部に比べて有意な活性の存在を認めた。これらの病変は、将来は癌に移行する可能性が有るものとして対処すべきものと考えられた。このように、早々期を含めた肝癌の診断に有効であることがわかり、臨床に役立つ成果が得られた。

Research Products

(16 results)

All Other

All Publications (16 results)

[Publications] Tahara,H. et .al: "Immuno-histochemical detection of human telomerase catalytic component, hTERT, in human colorectal tumor and non-tumor tissue sections."Oncpgene. 18. 1561-1567 (1999)
[Publications] Kitamoto,M. and Ide,T: "Telomerase activity in precancerous hepatic nodules."Cancer. 85. 245-246 (1999)
[Publications] Sugimoto,H. et al: "A new aspect of Epstein Barr virus-transformed human B-lymphoblastoid cell lines:senescence and immortalization."Mech, Aging Dev.. 107. 51-60 (1999)
[Publications] Nakamura,A. et. al: "Four novel mutations of the Fanconi anemia qroup A gene(FAA)in Japanese patients."J.Hum.Genet. 44. 48-51 (1999)
[Publications] Kakuo,S.et. al: "Human is a unique species among primates in terms of telomere length."Biochem. Biophys. Res. Commun. 263. 308-314 (1999)
[Publications] Yasui,W. et. al: "Immunohistochemical detection of human telomerase reverse transcriptase in normal mucosa and precancerous lesions of the stomach."Jpn.J. Cancer Res.. 90. 589-595 (1999)
[Publications] Harada,K, et. al: "Telomerase activity in central nervous system melignant lymphoma."Cancer. 86. 1050-1055 (1999)
[Publications] Nakamura,Y.,et. al: "Simple, rapid, sensitive and quantitative detection of telomere repeats in cell lysate by hybridization protection assay(HPA)"Clin. Chem.. 45. 1718-1724 (1999)
[Publications] Sugimoto, M. et. al: "Wrong use of"immortalization" for B-lympho-blastoid cell lines transformed by Epstein-Barr virus."J.Virol. 73. 9690-9691 (1999)
[Publications] Ishii,Y. et.. al: "Telomerase activity in hybrids between telomerase-negative and telomerase-positive immortal human cells is repressed in the cefferent complementation groups but not in the same complementation group of immortality."Mech. Aging Dev.. 110. 175-193 (1999)
[Publications] Nakamura,Y,et. al: "Quantitative re-evaluation of telomerase activity in cancerous and noncancerous gastrointestinal tissues."Mol. Carcinog.. 26. 312-320 (1999)
[Publications] Okui, M. et. al: "APG-2 protein, a member of the heat shock protein 110 family, is expressed high in various tissues during the rat development, but exceptionally low in adult heart."Neurochem, Internatl.. (in press). (2000)
[Publications] Okui,M.et.al: "MNB/DYRK gene cloned from the Down syndrome critical region is expressed high in rat brain and heart during development."Genomics. (in press). (2000)
[Publications] Takahashi, S. et. al: "Expression of telomerase component genes in hepatocellular carcinomas."Eur.J. Cancer. (in press). (2000)
[Publications] Takaiashi, H. et. al: "Precancerous hepatic nodules had significant levels of telomerase activity by sensitive quantitation using hybridization protection assay."Cancer. (in press). (2000)
[Publications] Aikata, H. et. al: "Telomere reduction in human liver tissues with age and chronic inflammation."Exp. Cell. Res.. (in press). (2000)

1999 Fiscal Year Annual Research Report

テロメラーゼ機能の解析と細胞の不死化・癌化への役割

Principal Investigator

井出 利憲 広島大学, 医学部, 教授 (60012746)

Research Products

[Publications] Tahara,H. et .al: "Immuno-histochemical detection of human telomerase catalytic component, hTERT, in human colorectal tumor and non-tumor tissue sections."Oncpgene. 18. 1561-1567 (1999)

[Publications] Kitamoto,M. and Ide,T: "Telomerase activity in precancerous hepatic nodules."Cancer. 85. 245-246 (1999)

[Publications] Sugimoto,H. et al: "A new aspect of Epstein Barr virus-transformed human B-lymphoblastoid cell lines:senescence and immortalization."Mech, Aging Dev.. 107. 51-60 (1999)

[Publications] Nakamura,A. et. al: "Four novel mutations of the Fanconi anemia qroup A gene(FAA)in Japanese patients."J.Hum.Genet. 44. 48-51 (1999)

[Publications] Kakuo,S.et. al: "Human is a unique species among primates in terms of telomere length."Biochem. Biophys. Res. Commun. 263. 308-314 (1999)

[Publications] Yasui,W. et. al: "Immunohistochemical detection of human telomerase reverse transcriptase in normal mucosa and precancerous lesions of the stomach."Jpn.J. Cancer Res.. 90. 589-595 (1999)

[Publications] Harada,K, et. al: "Telomerase activity in central nervous system melignant lymphoma."Cancer. 86. 1050-1055 (1999)

[Publications] Nakamura,Y.,et. al: "Simple, rapid, sensitive and quantitative detection of telomere repeats in cell lysate by hybridization protection assay(HPA)"Clin. Chem.. 45. 1718-1724 (1999)

[Publications] Sugimoto, M. et. al: "Wrong use of"immortalization" for B-lympho-blastoid cell lines transformed by Epstein-Barr virus."J.Virol. 73. 9690-9691 (1999)

[Publications] Ishii,Y. et.. al: "Telomerase activity in hybrids between telomerase-negative and telomerase-positive immortal human cells is repressed in the cefferent complementation groups but not in the same complementation group of immortality."Mech. Aging Dev.. 110. 175-193 (1999)

[Publications] Nakamura,Y,et. al: "Quantitative re-evaluation of telomerase activity in cancerous and noncancerous gastrointestinal tissues."Mol. Carcinog.. 26. 312-320 (1999)

[Publications] Okui, M. et. al: "APG-2 protein, a member of the heat shock protein 110 family, is expressed high in various tissues during the rat development, but exceptionally low in adult heart."Neurochem, Internatl.. (in press). (2000)

[Publications] Okui,M.et.al: "MNB/DYRK gene cloned from the Down syndrome critical region is expressed high in rat brain and heart during development."Genomics. (in press). (2000)

[Publications] Takahashi, S. et. al: "Expression of telomerase component genes in hepatocellular carcinomas."Eur.J. Cancer. (in press). (2000)

[Publications] Takaiashi, H. et. al: "Precancerous hepatic nodules had significant levels of telomerase activity by sensitive quantitation using hybridization protection assay."Cancer. (in press). (2000)

[Publications] Aikata, H. et. al: "Telomere reduction in human liver tissues with age and chronic inflammation."Exp. Cell. Res.. (in press). (2000)

井出利憲広島大学, 医学部, 教授 (60012746)