Recombinant Mammaglobin A Adenovirus-Infected Dendritic Cells Induce Mammaglobin A-Specific CD8+ Cytotoxic T Lymphocytes against Breast Cancer Cells In Vitro

Abstract

Mammaglobin A (MGBA) is a novel breast cancer-associated antigen almost exclusively over-expressed in primary and metastatic human breast cancers, making it a potential therapeutic target for breast cancer. The development of dendritic cell (DC)-induced tumor antigen specific CD8+ cytotoxic T lymphocytes (CTLs) may hold promise in cancer immunotherapy. In this study we constructed recombinant replication-defective adenoviral (Ad) vectors encoding MGBA and evaluated their ability to trigger anti-tumor immunity in vitro. DCs were isolated from the human peripheral blood monocyte cells (PBMCs) of two HLA-A33+ healthy female volunteers, and infected with adenovirus carrying MGBA cDNA (Ad-MGBA). After that, the Ad-MGBA-infected DCs were used to stimulate CD8+ CTLs in vitro and the latter was used for co-culture with breast cancer cell lines. The data revealed that infection with Ad-MGBA improved DC maturation and up-regulated the expression of co-stimulatory molecules and the secretion of interleukin-12 (IL-12), but down-regulated interleukin-10 (IL-10) secretion from DCs. Ad-MGBA-infected DC-stimulated CD8+CTLs displayed the highest cytotoxicity towards HLA-A33+/MGBA+ breast cancer MDA-MB-415 cells compared with other CD8+CTL populations, and compared with the cytotoxicity towards HLA-A33-/MGBA+ breast cancer HBL-100 cells and HLA-A33-/MGBA- breast cancer MDA-MB 231 cells. In addition, Ad-MGBA-infected DC-stimulated CD8+ CTLs showed a high level of IFNγ secretion when stimulated with HLA-A33+/MGBA+ breast cancer MDA-MB-415 cells, but not when stimulated with HLA-A33-/MGBA+ HBL-100 and HLA-A33-/MGBA-MDA-MB-231 cells. In addition, killing of CD8+CTLs against breast cancer was in a major histocompability complex (MHC)-limited pattern. Finally, the data also determined the importance of TNF-α in activating DCs and T cells. These data together suggest that MGBA recombinant adenovirus-infected DCs could induce specific anti-tumor immunity against MGBA+ breast cancers, which could provide a novel strategy in the immunotherapy of breast cancer. © 2013 Cui et al.