Efficient induction of anti-tumor immune response in esophageal squamous cell carcinoma via dendritic cells expressing MAGE-A3 and CALR antigens.

Despite advances in the various treatment options for esophageal squamous cell carcinoma (ESCC), its prognosis is still very poor with a 5-year survival rate of only 14-22%. Recently, among the various therapeutic approaches, the focus has shifted to immunotherapy, specifically immunotherapy involving dendritic cells (DCs), which depends on their maturation and antigen presentation to effector immune cells. Recent studies have suggested that melanoma-associated antigen 3 (MAGE-A3) is a potential immunotherapeutic target and also a candidate for the development of an anti-tumor vaccine. Calreticulin (CALR) has been shown to support induction of DC maturation. Therefore, in this study, we overexpressed MAGE-A3 and CALR on DCs and studied their potential to generate anti-tumor immune responses. We observed that adenovirus (Ad)-infected DCs overexpressing CALR and MAGE-A3 showed enhanced expression of CD80, CD83, CD86, and HLA-DR markers. Also, these DCs secreted higher levels of interleukin (IL)-12, which induces the T helper type 1 cell (Th1) response, and a lower level of IL-10, a negative regulator of the Th1 response. Furthermore, CALR/MAGE-A3-infected DCs stimulated CD8(+) cytotoxic T lymphocytes, which in turn secreted higher levels of interferon-γ, which induced cytotoxic effects on ESCC cells expressing MAGE-A3. In conclusion, our results revealed the potential of CALR/MAGE-A3-infected DCs to elicit a MAGE-A3-specific anti-tumor immunogenic response in ESCC. This proof-of-principle study may promote the future design and development of DC-based effective immunotherapy against ESCC.