Enhanced antitumor effect of cytotoxic T lymphocytes induced by dendritic cells pulsed with colorectal cancer cell lysate expressing α-Gal epitopes

Colorectal cancer (CRC) is one of the most common types of gastrointestinal malignancy. Traditional therapeutic options for CRC exhibit a limited effect. Adoptive cellular therapy has emerged as a new treatment strategy for CRC. Dendritic cells (DCs) are potent antigen-presenting cells. Specific cytotoxic T lymphocytes (CTLs) activated by DCs pulsed with tumor lysate have been reported to be a safe and promising treatment approach for CRC. However, the antitumor effect of specific CTLs remains limited. The low immunogenicity of tumor-associated antigens (TAAs) is the main reason for this limited therapeutic effect. In the present study, α-gal epitopes were synthesized on the CRC cell line SW620 to increase the immunogenicity of TAAs. DCs were pulsed with α-gal-expressing tumor lysate and CTLs were activated by these DCs. The cytotoxicity of CTLs was measured in vitro. The results demonstrated that DCs pulsed with α-gal-expressing tumor lysate can increase the frequency of CD3⁺CD8⁺ CTLs and natural killer T cells, increase the level of tumor necrosis factor-α produced by CTLs and enhance the cytotoxicity of CTLs against tumor cells. Therefore, this novel approach may be an effective treatment strategy for patients with CRC.