Abstract:Objective To study the specific killing effect of recombinant expression vector containing human breast cancer DF3 promotor and diphtheria toxin A fragment on human breast cancer cells implanted in vivo. Methods To establish human breast cancer xenograft in nude mice，thirtysix nude mice were divided into four groups at random，nine animals in each group. Human breast cancer cells of DF3 positive and negative（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 after if developed in the animals. The tumor weight was measured and calculated continually. The animals were killed at different time periods. The morphological changes were observed. The apoptosis index of cells was evaluated by insitu TUNEL. Immunocytochemical methods were used to detect the expression of Ki67,Bax and Bcl2 protein.
Results Human breast cancer xenograft were 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 experimental groups was significantly enhanced，which was associated with time and dosage. The expression of Ki67 and Bcl2 were downregulated, and the expression of Bax was elevated. 〖WTHZ〗Conclusions Recombinant expression vector PGL3DF3DTA could produce specific killing effect on DF3 positive human breast cancer cell line.