Inhibitory effects of recombinant bacillus Calmette-Guérin vaccines coexpressing tandem repeats of MUC1 and GM-CSF on the growth of breast cancer / 中华普通外科杂志

ABSTRACT

Objective To construct a recombinant bacillus Calmette-Guérin(BCG) vaccines based on different tandem repeats of MUC1 and GM-CSF, rBCG-MVNTR1/4/8-CSF, and to observe the ability of three recombinant BCG vaccines in the inhibition of breast cancer. Methods After MUC1 variable-number tandem repeats (MVNTR1/4/8) were cloned in a stepwise manner, the E. coli-Mycobacteria shuttle expression vector pDE22-MVNTR1/4/8-CSF were constructed by fusing MVNTR1/4/8 and GM-CSF, and then used to transform competent BCG by electroporation after identification by restriction endonuclease digestion analysis and DNA sequencing. A novel breast cancer vaccines, rBCG-MVNTR1/4/8-CSF was constructed. The expression of fused MVNTR1/4/8-CSF protiens was analyzed by SDS-PAGE and Western blot. The ability of rBCG vaccines inhibiting the growth of breast cancer was observed in hu-PBL-SCID mice. The specific T cell responses in mice were assessed by immunohistochemistry. Results The expression of recombinant MVNTR1/4/8-CSF fusion proteins were detected by SDS-PAGE and Western Blot in rBCG-MVNTR1/4/8-CSF vaccines, respectively. Tumor incidence in mice prophylactic immunized with rBCG-MVNTR4-CSF (37.5%) or rBCG-MVNTR8-CSF (25%) significantly decreased compared with PBS and BCG-pDE22 control ( 100% ) at 42 days after tumor implantation ( P ＜ 0. 05 ). MCF-7 tumor growth inhibition in rBCG- MVNTR4/8-CSF-immunized mice was more significant than that in controls ( P ＜0. 01 ).The inhibition effect of three rBCG vaccines on breast rumor growth appeared to rise with increase of numbers of the tandem repeats of MUC1. Survival rate was 75% of mice in the rBCG-MVNTR4-CSF-treated group and 87. 5% of mice in the rBCG-MVNTR8-CSF-treated groups at 70 days after tumor implantation; however,survival rate was only 12. 5% in control group( P ＜0. 05). The CD4-positive and CD8-positive lymphocytes were detected only in rBCG-MVNTR4/8-CSF-immunized mice. Conclusions rBCG-MVNTR4/8-CSF immunization inhibits breast cancer growth in mice.