Icariin suppresses tumor growth in vivo.
To determine whether the in vivo antitumor efficiency of icariin was consistent with its effects in vitro , MDA-MB-231 tumor-bearing mice and 4T1 tumor-bearing mice were treated with icariin at 20 mg/kg and 40 mg/kg. As shown in Fig. 6A-C, treatment with icariin at 20 mg/kg (P <0.01) or 40 mg/kg (P <0.005) significantly inhibited MDA-MB-231 tumor growth and weight in a dose-dependent manner in comparison with the control group. The body weight of the mice did not present any abnormal variation during the treatment process (Fig. 6D). Moreover, the results of immunohistochemistry analysis of the tumors (Fig. 6E) indicated that icariin inhibited the proliferation of nuclear Ki-67-positive cells, enhanced the expression of cleaved caspase3 to induce cell apoptosis and downregulated expression level of NF-κB in tumor sections. Moreover, western-blot analysis of isolated tumors revealed that icariin enhanced expression level of SIRT6 and inhibited nuclear expression level of NF-κB p65 (Fig. 6F). In the 4T1 tumor-bearing mouse model, icariin similarly retarded tumor growth significantly, and suppressed tumor cells proliferation and expression level of NF-κB (Fig. 6G-L). Overall, the above data suggested that icariin could suppress TNBC growth by inhibiting NF-κB signaling pathway, which is consistent with the in vitro data.