Figure 5. Let-7a suppresses tumor growth.

(A) Nude mice were injected subcutaneously with 2x10⁶ TPC-1 cells stably expressing let-7a, let-7a+AKT2 or miR-NC. Each treatment group contained 4 tumors. When the xenografts were visible, the width and length of tumors were measured. The tumor growth curve upon implantation was showed. (B) Representative pictures of xenograft tumors are shown. Bar=200μm. (C) Tumor growth were significantly inhibited in let-7a-overexpression group, and partly upregulated in let-7a+AKT2-overexpression group. The tumor weight was measured for each xenograft. (D) The levels of AKT2 from the tumor tissues of let-7a-expressing group were much lower than that of control group by immunoblotting assay, and partly upregulated in let-7a+AKT2-overexpression group. The density of AKT2 expression levels were quantified and normalized to the level of GAPDH. Error bars represent the mean±SD, (*, **) Significant difference when compared with the miR-NC group (P< 0.05)(P< 0.01). (^#, ^##) Significant difference when compared with the let-7a group (P< 0.05, P< 0.01). Bar =200μm.