DF3调控下的白喉毒素A片段在体内特异性杀伤人乳腺癌细胞的研究

Study on the Specific Killing Effect of Diphtheria Toxin A Fragment under Control of DF3 Promoter on Human Breast Cancer Cells In Vivo

目的研究新构建的含人乳腺癌DF3启动子和白喉毒素A片段的重组表达载体PGL3-DF3-DTA在体内对人乳腺癌细胞的特异性杀伤作用。方法4周龄裸鼠36只,随机分为实验组、空载体组、空白对照组、阴性对照组4组,每组9只。将DF3阳性和阴性的人乳腺癌细胞MCF-7和MDA-MB-231分别接种于相应的裸鼠皮下。待成瘤后,将重组表达载体PGL3-DF3-DTA和PGL3-DF3多次、多位点注射入相应裸鼠移植瘤内。连续测量瘤体大小,计算瘤体重量。在不同时间分批处死动物,用光镜进行形态学观察、用TUNEL法检测肿瘤细胞的凋亡、用免疫组化技术检测肿瘤内淋巴管和血管的生成情况。结果成功的建立了人乳腺癌裸鼠动物模型,经重组表达载体PGL3-DF3-DTA作用后的DF3阳性人乳腺癌细胞出现明显的凋亡现象,LYVE-1、F8基因表达水平降低。结论重组表达载体PGL3-DF3-DTA能在体内对DF3阳性的乳腺癌细胞产生特异性杀伤作用。

Objective To study the specific killing effect of recombinant expression vector containing human breast cancer DF3 promoter and diphtheria toxin A fragment on human breast cancer cells in vivo. Methods thirty-six BALB/C nude mice were divided into four groups at random, each group has nine animals. Human breast cancer cells of DF3 positive and negafive（MCF-7 and MDA-MB-231 ）were inoculated into corresponding animals respectively. Recombinant expression vector PGL3-DF3-DTA and PGL3-DF3 were inoculated into corresponding tumor when the animals grew up tumor. The tumor weight were measured and calculated continually. We killed the animals in different time and observed the morphological changes by means of light microscope. The apoptosis index of cells was evaluated by in-situ TUNEL. lmmunocytochemical methods were used to detect the condition of lymphanglogenesis and angiogenesis in tumor. Results Human breast cancer xenograft model was established in nude mice successfully. The human breast cancer cells treated by PGL3-DF3-DTA showed a typical apoptosis morphology and TUNEL detection analysis revealed the apoptosis index of the treatment groups was significantly enhanced, which was associated with time and dosage. The expression of LYVE-I and F8 were down regulated. Conclusion Recombinant expression vector PGL3-DF3-DTA could produce specific killing effect on human breast cancer cell line of DF3 positive in vivo.