OK-432 Suppresses Proliferation and Metastasis by Tumor Associated Macrophages in Bladder Cancer.

OK-432, a Streptococcus-derived anticancer immunotherapeutic agent, has been applied in clinic for many years and achieved great progress in various cancers. In the present study, we investigated its anticancer effect on bladder cancer through tumor associated macrophages (TAMs). MTS assay validated OK-432 could inhibit proliferation in both T24 and EJ bladder cell lines. OK-432 also induced apoptosis of bladder cancer cells in vitro. Consequently, we demonstrated that OK-432 could suppress the bladder cancer cells migration and invasion by altering the EMT-related factors. Furthermore, using SD rat model, we revealed that OK-432 inhibited tumor growth, suppressed PCNA expression and inhibited metastasis in vivo. Taken together, these findings strongly suggest that OK-432 inhibits cell proliferation and metastasis through inducing macrophages to secret cytokines in bladder cancer.