p53/microRNA-374b/AKT1 regulates colorectal cancer cell apoptosis in response to DNA damage

Colorectal cancer (CRC) has a rising morbidity worldwide and its resistance to chemotherapy has been observed in clinical treatment. Tumor suppressor p53 is well-studied in CRC, but little is known about its effects during DNA damage of CRC cells. This study was aimed at uncovering potential mechanisms of p53 regarding microRNA-374b and v-akt murine thymoma viral oncogene homolog 1 (AKT1) during DNA damage of CRC cells. CRC cells HCT116 and HT29 were transfected with p53-specific small interfering RNA (siRNA), p53 overexpression vector or miR-374b inhibitor, and then treated with 10 µM bleomycin (BLM) for 24 h to induce DNA damage. Primary (pri), precursor (pre) and mature miR-374b levels were quantified by qRT-PCR. AKT1 and p53 protein levels were detected by western blotting. Cell apoptosis changes were assessed by flow cytometry. AKT1 mRNA was detected to be induced by BLM treatment (P