血卟啉单甲醚—光动力疗法诱导HeLa细胞凋亡机制的初探

【作者】 蔡雄伟；

【导师】 刘承宜； 顾瑛；

【作者基本信息】 华南师范大学 ， 生理学， 2004， 硕士

【摘要】 光动力疗法(photodynamic therapy，PDT)是一种很有潜力的肿瘤治疗方法，许多国家都在开展这方面的研究。为临床上的进一步应用，在本文，我们初步研究了使用我国自主开发的第二代光敏剂——血卟啉单甲醚进行的光动力疗法诱导HeLa细胞凋亡的分子机制。 本文首先介绍了有关光动力疗法的基本知识和治疗肿瘤的机制，概述了细胞凋亡的信号通路情况，并总结了光动力疗法对细胞凋亡的调节。然后介绍本文的研究工作：利用流式细胞仪找出最佳的光敏剂和光照强度组合，使凋亡率发生在比较高的组合区间；再通过MTT(3-(4，4-dimethylthiazol-2-1)-2,5-diphenyl tetrazolium bromide)法和特异的抑制剂，研究钙离子和ERK1／2(extracellular-regulated kinase 1／2)途径在PDT中的作用；进一步通过蛋白印迹技术，探讨PDT对Bcl-2(B-cell lymphoma／leukemia-2)作用。通过研究取得了如下结果： 1．细胞会发生凋亡； 2．在低剂量时，钙浓度的升高能够阻止细胞的凋亡；高剂量时钙浓度的变化对细胞的凋亡没有影响； 3．在低剂量时，PDT激活ERK1／2来阻止凋亡；而高剂量时，通过ERK1／2来促进凋亡的发生； 4．通过蛋白印迹发现HMME-PDT对Bcl-2没有明显的作用。更多还原

【Abstract】 Photodynamic therapy (PDT) is a promising tumor treaty and attracts many countries’ attention. For the purpose of further clinical application, we study the HeLa apoptosis induced by HMME-PDT using the hematoporphyrin monomethyl ether (HMME), which is the 2rd photosensitizer developed by our country.In this paper, the base information of PDT, the mechanism of ablating tumor and the signal transduction are introduced firstly. Then, we study the effect of PDT on apoptosis. According to the former research, flow cytometry (FCM) is used to examine apoptosis induced by the optional photosensitizer concentration and illumination. Calcium ion often benefits to apoptosis. With the help of molecular probe and the chelate of calcium ion, we define the effect of calcium ion on apoptosis and evaluate the ERKl/2’s role on apoptosis by means of PD98059. Finally, the role of PDT on Bcl-2 is defined by western blot. The main conclusions are listed in the following:1. HMME-PDT can induce HeLa cell apoptosis.2. There is a calcium oscillation after HMME-PDT. In the case of low laser power, increasing intracellular calcium ion concentration ([Ca2+]i) to certain extent can rescue cell from apoptosis. But this does not work in the case of high laser power, i.e., increasing [Ca2+], does not affect the cell apoptosis when the laser power is higher.3. In the case of low laser power, HMME-PDT can activate ERK1/2 signal transduction pathway, which stimulates cell to proliferate. However, in higher power, ERK1/2 may promote cell to apoptosis.4. HMME-PDT has no significant effect on the content of Bcl-2.更多还原