Chk1は,p53,Bcl-2,およびcaspase-3をバイパスするDNA損傷に対するcaspase-2アポプトティック反応を抑制する
Samuel Sidi1, Takaomi Sanda, Richard D Kennedy
1Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
Cell
|May 31, 2008
まとめ
チェックポイントキナーゼ1 (Chk1) 阻害は,代替アポプトシス経路を活性化することによって,がん細胞におけるDNA損傷による細胞死を再生する. このChk1-抑制された経路は,p53変異とBcl-2過剰発現を回避し,新しい治療戦略を提供します.
科学分野:
- 分子生物学は分子生物学である.
- 細胞生物学 細胞生物学
- がん研究 がん研究
背景:
- 癌細胞は,p53変異またはBcl-2ファミリータンパク質過剰発現を通じてアポトーシスを回避し,悪性変異と治療抵抗につながる.
- チェックポイントキナーゼ1 (Chk1) は,DNA損傷反応において重要な役割を果たしており,その抑制はがん治療戦略として検討されている.
研究 の 目的:
- Chk1の阻害によって,がん細胞におけるDNA損傷によるアポトーシスを回復させるメカニズムを調査する.
- Chk1阻害剤媒介細胞死に関与する主要な分子プレーヤーと経路を特定する.
主な方法:
- p53変異とヒト腫瘍細胞系を持つゼブラフィッシュの胚を用いた.
- DNAの損傷を誘発するためにガンマ放射線を使用した.
- アポトーシス,DNAの断片化,カスパース (カスパース-3,カスパース-2) とキナーゼ (ATM,ATR) の活性化を評価した.
- アポプトシス過程におけるp53およびBcl-2ファミリータンパク質の役割を調査した.
主要な成果:
- P53変異種ゼブラフィッシュの胚において,Chk1の枯渇または抑制により,ガンマ放射線誘発によるアポトーシスが回復した.
- カスパース-3の活性化とは無関係な新しいアポプトシスプログラムが特定されました.
- この代替経路はATM,ATR,カスパース-2を必要とし,p53喪失やBcl-2/xl過剰発現によって影響を受けません.
- Chk1阻害剤で治療されたヒト腫瘍細胞はATM,ATR,カスペーゼ2を活性化させ,カスペーゼ2依存アポトーシスを引き起こし,p53欠乏とBcl-2過剰を回避した.
結論:
- 進化的に保存された"Chk1-抑制"経路は,新しいアポプトシスプロセスを表しています.
- この経路はChk1阻害剤に反応し,p53とBcl-2の変化には無感性である.
- Chk1をターゲットにすることは,p53またはBcl-2の状態に関係なく,アポトーシス調節の欠陥を有するがんに対する有望な治療戦略を提供します.
関連する概念動画
DNA Damage can Stall the Cell Cycle
8.5K
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
8.5K
Abnormal Proliferation
4.0K
Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the...
4.0K
Caspases
8.7K
Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside...
8.7K
The Extrinsic Apoptotic Pathway
6.2K
The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
6.2K
The Intrinsic Apoptotic Pathway
6.2K
Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
6.2K
DNA Damage Can Stall the Cell Cycle
2.4K
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
2.4K


