Fig. 5. Let-7a-1-5p influenced the metastatic ability of CT26.WT in BALB/c.

a, b Twelve days after the injection of reconstructed CT27 cells, the whole-body in vivo imaging system was used to monitor the dynamic growth of the metastases in BALB/c mice. Compared to the control group (n = 6), a lower incidence of CRLM (16.7% vs. 4/6, P = 0.242) with less powerful fluorescence (P = 0.05) was detected in the let-7a downregulated group (n = 6), and more powerful fluorescence in the upregulated group (P < 0.05). However, the incidence of CRLM in the overexpression group (n = 6) did not achieve statistical significance (6/6 vs. 5/5) compared to the control group (n = 6). Macro- and microscopic changes were observed after performing anesthesia and hepatectomies. More discrete tumor nodules were visible throughout the livers in the upregulated group, and it was identical with histological and morphological characteristic observed from H&E stain. c, d The number and the maximum diameter of metastases in different groups. Dramatically decreased trends in number (P < 0.05) and diameter (P = 0.05) were detected in the let-7a-1-5p suppressive group compared with the control group and increased number of metastases (P < 0.05) and dramatically larger diameter (P < 0.05) in the upregulated group. e Abdominal wall metastases (where the red arrow is pointing) were detected in the two of six mice in the let-7a-1-5p overexpression group. However, no abdominal wall metastasis was found in the other groups. Chi-square test was used to test the rates of incidence of metastasis. Nonparametric test was used to test the total powerful of fluorescence, the number of metastatic foci, and the maximum diameter of metastasis. *P < 0.05, **P < 0.01