- 學位論文
探討組蛋白去乙醯酵素8於乳癌生成之角色及其在乳癌治療上的應用
To Investigate the Alterations of Histone Deacetylase 8 (HDAC8) in Breast Tumorigenesis and Its Application in Cancer Therapeutics
摘要
近年來，乳癌的高發生率已經受到全世界越來越多的關注，第一類組蛋白去乙醯酶 (Class I HDACs) 的過度表現則被認為是造成乳癌的原因之一。在本研究中，我們發現有25%的乳癌患者其腫瘤組織部位的HDAC8 mRNA表現量高於其正常乳房部位1.5倍以上。由臺北醫學大學生藥所黃偉展副教授實驗室所提供之半合成lovastatin衍生物-D compound因具有HDAC8活性的抑制作用，故可能在乳癌藥物的開發上作為一潛力先驅藥物。D compound具有抑制MDA-MB-231乳癌細胞爬行之能力，並具有抑制MDA-MB-231、MCF-7、及T47D三株乳癌細胞存活率之作用，其IC50 (可抑制50%細胞存活率之藥物濃度) 依序分別為16.03μM、20.73 μM、及29.53 μM。利用流式細胞儀分析之結果顯示D compound可降低細胞增生能力，並造成細胞週期G0/G1期停滯。另外，藉由偵測細胞中γ-H2AX及cleaved-PARP蛋白之程度，則顯示D compound會誘發去氧核醣核酸損害 (DNA damage) 及細胞凋亡。在MDA-MB-231細胞中，D compound會誘發大量活性氧化物 (reactive oxygen species, ROS) 的產生，並且導致一系列DNA損壞反應途徑 (damage response pathway) 中蛋白質的磷酸化，如：ATM、Chk1、Chk2、p53、H2AX，以及p21蛋白的表現，故推測可能是造成DNA損害及細胞存活率降低的主要原因。總而言之，lovastatin新穎衍生物D compound可能藉由抑制HDAC8活性而抑制MDA-MB-231細胞爬行之能力，並透過增加ROS的程度及DNA損害造成細胞週期停滯，因此在乳癌上或許具有抗癌之潛力。
並列摘要
The high incidence rate of breast cancer in recent years has been attracting more and more attentions worldwide. The overexpression of Class I histone deacetylases (HDACs) was considered to be a key factor contributing to its tumorigenesis. In this research, we revealed that 25% of breast cancer patients exhibited an over 1.5-fold HDAC8 mRNA level in their tumor parts. A novel semi-synthetic lovastatin derivative provided by Dr. Wei-Jan Huang, called D compound, exhibited HDAC8 inhibitory activity, and might act as a potential lead compound in breast cancer therapeutics. D compound had the potency in inhibiting the migratory ability of MDA-MB-231 breast cancer cells and reducing cell viabilities of MDA-MB-231, MCF-7, and T47D breast cancer cells with IC50 16.03μM, 20.73 μM, and 29.53 μM respectively. Analytical results from flow cytometry indicated that D compound may reduce cell proliferation and induce G0/G1-phase cell cycle arrest. In addition, D compound induced DNA damage and apoptosis with the detection of γ-H2AX and cleaved-PARP respectively. It also increased the ROS level in MDA-MB-231 cells and activated several proteins involed in DNA damage response pathway, such as ATM, Chk1, Chk2, p53, H2AX, and p21, which might be a factor contributing to DNA damage and reduced cell viabilities. In conclusion, our novel lovastatin derivative, D compound, may reduce the migratory ability of MDA-MB-231 cells by inhibiting HDAC8 activity, and may induce cell cycle arrest through ROS activation and DNA damage, exhibiting a potential anti-cancer effect on breast cancer cells.
參考文獻
延伸閱讀
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