Interleukin 21 treatment in a murine model as a novel potential cytokine immunotherapy for colon cancer.

BACKGROUND: Interleukin 21 (IL-21), which belongs to the common γ-chain (γc) family, is a novel tumor suppressor that has been shown to affect T-cell proliferation, survival and function. However, the role of IL-21 in colon cancer remains unclear.

OBJECTIVES: We sought to determine whether IL-21 could inhibit the progression of colon cancer in mice; we also explored the mechanisms underlying the immunological effects of IL-21 in colon cancer.

MATERIAL AND METHODS: Exogenous IL-21 protein was expressed to treat tumor-bearing mice and the production of cytokine interleukin 4, interferon gamma and lambda from CD4+ T, CD8+ T, and NK cells were measured, along with the survival times of these tumor-bearing mice.

RESULTS: Interleukin 21 promoted the secretion of interferon gamma from the CD4+ T, CD8+ T and NK cells and it enhanced the production of interferon lambda by the NK cells. More importantly, IL-21 treatment significantly enhanced antitumor effects in favor of tumor eradication. We also found that CD8+ T and NK cells are necessary for the antitumor immune responses elicited by IL-21.

CONCLUSIONS: Interleukin 21 is a powerful tool for activating CD8+ T cells and NK cells which exhibit potent cytolytic effector functions and should therefore be exploited for anticancer immunotherapy. Our findings support the development of a novel cytokine immunotherapy against colon cancer.