| 摘要: | 薑黃素(bis（4-hydroxy-3-methoxy-phenyl）-1,6-diene -3,5-dione)是最常被來研究的化學藥劑，它使由天然植物薑黃的根部所萃取而來的成分，研究發現薑黃素可以抑制、阻止致癌之機轉。在中醫方面，被用來治療發炎相關疾病也有幾千年的歷史。對於有關薑黃素的研究文獻指出，在許多誘導細胞產生凋亡的實驗中發現，薑黃素具有抗腫瘤、抗氧化及抗發炎的功效。本實驗中要去證明薑黃素，這個容易誘導細胞產生凋亡的試劑，在對於人類鼻咽癌細胞株(NPC 076)及人類鱗狀上皮舌癌細胞株(SCC-4)造成其細胞週期停滯與細胞發生凋亡現象之機制探討。在人類鼻咽癌細胞株的實驗中發現，利用流式細胞儀分析薑黃素添加或給予後細胞週期會停滯於G2/M期，再利用西方墨點法證明其細胞週期相關蛋白，結果發現，p53和p21蛋白表現量增加，而Cyclin B、Cdk1和Cdc25c之表現量減少，這些結果再次證實薑黃素誘導人類鼻咽癌細胞株細胞週期停滯於G2/M期。此外，薑黃素會促使caspase 3和caspase 9活化，也會導致Bax表現量增加，而抑制了Bcl-2的蛋白表現，造成粒線體膜電位改變，而使粒線體內與細胞凋亡之相關蛋白 Cytochrome c的釋出，因而引發了一連串的凋亡反應。然而在人類鱗狀上皮舌癌細胞株實驗中，經由流式細胞儀分析其細胞週期之變化，發現到經薑黃素刺激後其細胞週期也是停滯於G2/M期，利用西方墨點法觀察發現，Cyclin B、Cdk1和Cdc25c其表現量隨著作用時間增加而減少，再次證明細胞週期停滯於G2/M期。薑黃素會導致SCC-4 cells產生內質網壓力，造成鈣離子的釋出，使caspase 12活化，進而活化了下游的凋亡機制。除此之外，薑黃素也會降低細胞內Bcl-2的表現量，導致粒線體膜電位改變，使cytochrome c由粒線體中釋出，促使下游caspase 3和caspase 9的活化，因而使凋亡路徑開啟。總而言之，薑黃素藉由內質網和粒線體路徑，誘導NPC 076細胞株和SCC-4 細胞株走向細胞凋亡。
Curcumin(bis（4-hydroxy-3-methoxy-phenyl）-1,6-diene -3,5-dione), one of the most studied chemopreventive agents, is a natural compound extracted from the root of the plant Curcuma that allows suppression, retardation or inversion of carcinogenesis and treatment of different inflammatory diseases in traditional Chinese medicine for thousands of years. The active component of turmeric responsible for this activity, curcumin, was identified almost two centuries ago. Curcumin is also described as an anti-tumoral, antioxidant and anti-inflammatory agent capable of inducing apoptosis in numerous cellular systems. In this study, we clarified that curcumin, an apoptoic inducer, induced cell cycle arrest and apoptosis in the human nasopharyngeal cancer cells (NPC-076) and human squamous cell carcinomas of the tongue (SCC-4). Apoptotic mechanisms and G2/M arrest in this system were investigated. Cell cycle and apoptosis analysis were examined by flow cytometry and associated protein levels were determined by Western blotting. In the human nasopharyngeal cancer cells (NPC-076) , flow cytometric analysis revealed that curcumin induced G2/M arrest and Western blotting analysis revealed that curcumin promoted p53 and p21 and inhibited the levels of cyclin B, Cdk1 and Cdc25c before leading to G2/M arrest in NPC 076 cells. Curcumin promoted caspase-3 and -9 activities, increased the levels of Bax and decreased the levels of Bcl-2 before decreasing the levels of mitochondrial membrane potential which caused the release of cytochrome c that led to apoptosis. In the other cells, human squamous cell carcinomas of the tongue (SCC-4) , flow cytometric analysis revealed that curcumin induced G2/M arrest and Western blotting analysis revealed that curcumin inhibited the levels of cyclin B, Cdk1 and Cdc25c before leading to G2/M arrest in SCC-4 cells. Curcumin induced ER stress based on the release of Ca2+ and promoted caspase 12 activities from examined SCC-4 cells. Curcumin promoted caspase-3 and -9 activities and decreased the levels of Bcl-2 before decreasing the levels of mitochondrial membrane potential which caused the release of cytochrome c that led to apoptosis. Therefore, curcumin could promoted the ER-induced and mitochondria-induced apoptosis of NPC 076 cells and SCC-4 cells. |
