Recombinant Plasmid PGL3-DF3-DTA For The Treatment Of Breast Cancer: A Study Of Balb/C Nude Mouse Model

Object Diphtheria toxin A chain (DTA) was introduced as a candidate for cancer cell killing by ribosylating the EF2 translation-initiation factor and inhibiting protein synthesis. Genetic recombination immunotoxin conjugated by the DTA and different vectors can selectively kill cells that express special protein, specially tumor cells. DF3 antigen (also designated MUC1 and episialin) is a member of a family of high molecular weight glycoproteins which are aberrantly overexpressed in over 75% of primary human breast cancers. And it is the relative antigen of human breast cancers which is highly specificity. Expression vector (pGL3-DF3-DTA) containing transcriptional regulation sequence of human breast carcinoma DF3/MUC1 promoter and diphtheria toxin A-chain gene(PGL3-DF3-DTA)inject into the breast cancer xenograft on the nude mouse and observe recombinant plasmid PGL3-DF3-DTA effect of inhibition of human breast cancer growth and cancer tissue apoptosis.Methods 1. To construct the nude mouse modles, the MCF-7 cell line was injected into the subcutaneousness of the nude mouse ridge. 2. Normal sodium, plasmid PGL3-DF3 and recombinant plasmid PGL3-DF3-DTA were respectively injected into the breast cancer xenograft on the nude mouse with some kind of dose every three days. 3. The tumor volume was measured before every injection. 4. The mice were killed after five injections. The histopathological changes of the tumor were observed by HE stain. Apoptosis in situ was detected by TUNEL method. Tumor cell were analyzed with flow cytometery to detect apoptosis and cell cycle.Results 1. The human cancer nude mouse model was constructed successfully. 2. The recombinant plasmid therapeutic group grew slower than that of the control groups, and the tumor volume of therapeutic group has a significant reduction after therapy (P<0.01). And the growth inhibitory rate was 50.08%. 3. Apoptosis rate of therapeutic group was higher than that of the normal sodium group and the plasmid PGL3-DF3 group.Conclusions Expression vector (pGL3-DF3-DTA) containing transcriptional regulation sequence of human breast carcinoma DF3/MUC1 promoter and diphtheria toxin A-chain gene(PGL3-DF3-DTA)results in marked inhibition of human breast cancer growth in nude mice. It may be a novel gene therapy approach for human breast cancer.