Construction and Structural Assessment of Nanocapsule Containing HER2-MUC1 Chimeric Protein as a Candidate for a Vaccine Against Breast Cancer

Background: Among all types of malignant diseases, breast cancer has worldwide importance because of the high mortality rate in women aged fewer than 50 in the developing countries. Identification of immunogenic antigens and the generation of specific antibodies against cancer cells are the most successful strategies for early detection and effective treatment of breast cancer. Objectives: In the current study, a chimeric protein consisting of two specific surface antigens, MUC1 and HER2, were used for the production of chitosan nanoparticles and evaluated as a vaccine candidate. Methods: The pET-28a expression vector harboring the HER2-MUC1 gene was constructed. Expression of the protein in E. coli BL21 (DE3) was induced using IPTG. The recombinant HER2-MUC1 (HM) protein was purified using a Ni-NTA column and confirmed by western blotting. Chitosan nanoparticles containing the target protein were prepared and the lymphocytes viability was evaluated using MTT assay. Results: The expression of the recombinant protein with molecular weight of 40 kDa was confirmed using SDS-PAGE and Western blotting. The electric charge and the size of the nanoparticles were determined and verified by a Zeta Sizer device. The evaluation of IgG and IgA titration suggested that inducing humoral and mucosal immune responses by administering nanoparticles containing the chimeric protein. Analysis of cell-mediated immunity showed that the chimeric HM protein could induce specific splenocyte proliferation in immunized mice. Conclusions: It seems that HM nanoparticles can be utilized as a vaccine candidate for inducing the cellular and humoral immune response against breast cancer.