IQDMA 對人類血癌細胞K562 細胞週期之抑制與凋亡機制探討

Induction of G2/M Phase Arrest and Apoptosis by a Novel Indoloquinoline Derivative, IQDMA, in K562 Cells

林逸翔(Yi-Hsiung Lin)

指導教授 ： 林信仁

高雄醫學大學/生命科學院/醫藥暨應用化學研究所/碩士(2006年)

摘要

化合物N’-(11H-indolo[3,2-c]quinolin-6-yl)-N,N-dimethylethane-1,2-diamine ( IQDMA )是以indoloquinoline為主架構進行合成出來的產物之一，已被證實對多種人類癌症細胞株具有抗腫瘤的活性，因此我們將它用於測試是否對人類血癌細胞株是否同樣具有抗癌活性。在本次實驗中可以觀察的到，IQDMA可以調控CDKIs蛋白質p21和p27活化，Cdk1和Cdk2減少，進而將細胞週期停滯在G2/M階段，但對於其他如cyclin A、cyclin B1、cyclin D3與Cdc25c皆無影響。藉此證明IQDMA對於人類血癌細胞株K562具有細胞週期的抑制效果，藉由sub G1的增加、PARP的斷裂、死亡受體Fas L的活化與其caspase的表現，我們可知IQDMA是藉由活化死亡受體Fas，從而經由caspase的活化而使K562走向細胞凋亡的。我們研究的結果顯示caspase-8、-3與caspase-9先後活化的時間點，並使用各種caspase的抑制劑去探討其確實的路徑，在caspase-8和caspase-3抑制劑皆可使sub G1減少，惟獨caspase-9抑制劑無法有效抑制的情況下證實IQDMA造成細胞凋亡的主要路徑為caspase-8和caspase-3。我們也進一步探討其上游MAPK蛋白質對IQDMA之反應的表現，發現p-JNK有明顯活化的現象，在加入p-JNK抑制劑後，也可減少K562的死亡。
這些結果有助於我們探討IQDMA對於K562細胞的生長抑制、細胞週期停滯及細胞凋亡的作用機制。

關鍵字

IQDMA ； G2/M細胞週期抑制 ； 細胞凋亡

並列摘要

N’-(11H-indolo[3,2-c]quinolin-6-yl)-N,N-dimethylethane-1,2-diamine ( IQDMA ), an indoloquinoline compound, was a novel antineoplastic agent with broad spectrum of antitumor activities against many human cancer cells. IQDMA-induced G2/M arrest was accompanied by up-regulation of cyclin-dependent kinase inhibitors ( CDKIs ), p21 and p27, and down-regulation of Cdk1and Cdk2, while IQDMA had no effect on the levels of cyclin A, cyclin B1, cyclin D3, and Cdc25C. IQDMA also caused a marked increase in apoptosis, as characterized by apoptotic body formation, increase of sub G1 population, and poly (ADP-ribose) polymerase (PARP) cleavage. Further mechanistic analysis demonstrated that IQDMA upregulated FasL protein expression, and kinetic studies showed the sequential activation of caspase-8, caspase-3 and caspase-9. Both caspase-8 and caspase-3 inhibitors, but not a caspase-9 specific inhibitor, suppressed IQDMA-induced cell death. These molecular alterations provide an insight into IQDMA-caused growth inhibition, G2/M arrest and apoptotic death of K562 cells.
This results could help us to find out the mechanism of IQDMA-induced the anti-proliferation, cell cycle arrest, and apoptosis on K562 cells in vitro.

並列關鍵字

IQDMA ； G2/M arrest ； apoptosis ； K562 cells

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