Figure 7. Loss of MiR34a facilitates tumor invasion after AOM/DSS treatment.

(A) Expression of miR-34a in colon tissue of WT and Stat3^ΔIEC mice. (B) Expression of Il6 mRNA in colon tissue of Mir34a^F/F mice after 5 days of DSS treatment. (C) Expression of miR-34a in colon epithelial cells of Mir34a^F/F mice after 5 days of DSS treatment. (D) Schematic overview of the CAC regimen as described in Methods. (E) Outline of the Mir34a targeting strategy in mice. (F) Genotyping PCR for determination of Mir34a^–/– mice. (G) Tumor incidence in indicated mice (n ≥ 10 for each genotype). (H) Mean tumor size in indicated mice (n ≥ 5 for each genotype). (I) Tumor cell proliferation was determined by BrdU incorporation. Percentage of proliferation indicates BrdU-positive cells (n ≥ 10 tumors of each genotype). (J) Tumor cell apoptosis was determined by detection of cleaved caspase-3. Percentage of positive cells is indicated (n ≥ 10 tumors of each genotype). (K) H&E-stained sections of colons from Mir34a^F/F and Mir34a^–/– mice with arrows indicating magnified areas showing tumor morphology and representative invasive colon carcinoma in Mir34a^–/– mice. Scale bars: 500 μm. (L) Percentage of mice showing invasive tumors for indicated genotypes. Number of mice with invasive tumors/total number of mice for each genotype is indicated above the bars. Mean values ± SEM are provided. *P < 0.05; **P < 0.01; ***P < 0.001.