Gemcitabine-treated pancreatic cancer cell medium induces the specific CTL antitumor activity by stimulating the maturation of dendritic cells

●GEM could not stimulate the maturation of DCs in a direct manner.●GEM-treated medium stimulates the maturation of DCs.●GEM-treated medium contains elevated level of Hsp70.●DCs pulsed with GEM-treated medium induced an enhanced cytotoxic T lymphocytes (CTLs) antitumor activity.

Gemcitabine (GEM) is a first line chemotherapeutic drug for advanced pancreatic cancer. Dendritic cell (DC) vaccine is a promising method of immunotherapy for malignant tumor. Recent research has indicated that gemcitabine can enhance the efficacy of DC vaccine, but precise mechanism is still unknown. Here, we aimed to investigate the effect of GEM on DCs. The results showed that GEM-treated pancreatic cancer cell medium stimulated maturation of DCs. When co-cultured with autologous T lymphocytes, the pulsed DCs promoted the proliferation of T cells, and exhibited specific cytotoxic T lymphocytes (CTLs) antitumor activity. Further research showed that stimulation of DC maturation may be related to the elevated level of Hsp70 induced by GEM. Our study indicates that GEM changes the immunogenicity of tumor cells, and enhances the efficacy of DC based immunotherapy for pancreatic cancer.