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ベータ-カタニンは,結腸がん細胞におけるサイクリンD1の発現を調節する
1University of California, San Francisco, School of Medicine, Cancer Research Institute, 94143-0128, USA.
Nature
|April 14, 1999
まとめ
アデノマ型ポリポシス・コリ (APC) 遺伝子の変異により,β-カタニンが蓄積され,大腸がんを誘発する. このβ-カテニンはサイクリンD1を活性化し,細胞サイクル進行と腫瘍の成長を促します.
科学分野:
- 分子生物学は分子生物学である.
- がん遺伝学 がん遺伝学
- 細胞サイクル規制について
背景:
- アデノマ型ポリポシス・コリ (APC) 腫瘍抑制遺伝子の変異は,ヒトの大腸がんにおいて一般的です.
- APC機能の喪失はベータ-カテニンの蓄積につながり,結腸癌,メラノーマ,肝癌を含む様々な癌で観察されています.
- 蓄積されたβ-カタニンはTCF/LEF転写因子と相互作用し,標的遺伝子を活性化します.
研究 の 目的:
- サイクリンD1プロモーターの活性化におけるβ-カタニンの役割を調査する.
- TCF/LEF結合部位がβ-カタニン媒介サイクリンD1活性化に不可欠であるかどうかを判断する.
- 変異性β-カタニンとTCF抑制がサイクリンD1発現と細胞サイクル進行に与える影響を明らかにする.
主な方法:
- シクリンD1プロモーターの活性に対するβ-カタニンの効果の分析.
- サイクリンD1プロモーター内の重要なTCF/LEF結合配列の特定.
- 変異性β-カタニニンを発現する細胞におけるサイクリンD1mRNAおよびタンパク質レベルの評価.
- 遺伝子発現と細胞サイクル停止に対する支配的負のTCF効果の評価.
主要な成果:
- ベータ-カテニンは,サイクリンD1プロモーターからの転写を活性化し,TCF/LEF結合部位を必要とします.
- 変異したβ-カテニンは,サイクリンD1mRNAとタンパク質の構成的な高いレベルにつながります.
- 腫瘍性p21rasは,EtsまたはCREB結合部位経由でサイクリンD1の転写を強化します.
- 主要負のTCFはサイクリンD1の発現を抑制し,G1細胞サイクル停止を引き起こし,サイクリンD1の再発によって救出されます.
結論:
- APC変異によって引き起こされる異常なβ-カテニンの蓄積は,腫瘍変異に寄与する.
- ベータ-カテニンは,サイクリンD1の蓄積を誘導し,細胞周期の調節不全につながるので,がんを促進します.
- ベータ-カタニンまたはTCF経路をターゲットにすることで,異常なベータ-カタニンシグナル伝達を持つがんの治療戦略を提供することができます.
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