Interleukin-17 promotes metastasis in an immunocompetent orthotopic mouse model of prostate cancer.

Metastasis of prostate cancer causes substantial morbidity and mortality. The role of chronic inflammatory factors in promoting the development of prostate cancer metastasis remains unexamined due to a lack of immunocompetent animal models. Here we report an orthotopic mouse allograft model of prostate cancer that was used to assess interleukin-17's role in prostate cancer metastasis. A luciferase gene was stably introduced into a mouse prostate cancer cell line MPC3, named as MPC3-luc. MPC3-luc cells were mixed with Matrigel™ and inoculated into C57BL/6 mouse prostates, with recombinant mouse interleukin-17 (IL-17) (treatment group) or without IL-17 (control group). Bioluminescent imaging was used to track the growth and metastasis of prostate cancer metastasis. Immunohistochemistry was performed to confirm metastasis. Mice in the IL-17 treatment group had significantly higher incidence of metastasis than mice in the control group. However, there was no detectable difference in primary prostate tumor growth. Metastases were confirmed as originating from prostate cancer through staining for luciferase protein expression. Our findings suggest that interleukin-17 promotes prostate cancer metastasis in an orthotopic mouse allograft model.