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<0.05), but its protein level was strongly inhibited. Knockdown of p53 reversed the inhibition of AKT1 protein by BLM. Overexpression of p53 in p53-knockout HCT116 and HT29 cells upregulated the AKT1 regulator miR-374b (P<0.05), and knockdown of p53 reversed the induction of miR-374b by BLM. qRT-PCR suggested that besides mature miR-374b, p53 could also promote pre-miR-374b level (P<0.05), rather than pri-miR-374b. Moreover, inhibition on miR-374b relieved the suppressed AKT1 protein, and reduced cell apoptosis induced by BLM. These data depict the p53/miR-374b/AKT1 signaling that may regulate BLM-induced apoptosis in CRC cells, thus facilitating to improve the outcome of chemotherapy in CRC.
Department of Gastrointestinal Surgery, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China.
Hangjun
H
Gong
Department of Gastrointestinal Surgery, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China.
Yu
Y
Cao
Department of Gastrointestinal Surgery, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China.
Gang
G
Han
Department of Gastrointestinal Surgery, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China.
Yun
Y
Zhang
Department of Gastrointestinal Surgery, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China.
Qing
Q
You
Department of Gastrointestinal Surgery, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China.
Yidong
Y
Wang
The First Department of Endoscopy, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China.
Yamin
Y
Pan
D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001761:Bleomycin / Q000008:administration & dosage; D049109:Cell Proliferation / Q000187:drug effects / Q000235:genetics; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D004249:DNA Damage / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D055785:Gene Knockdown Techniques; D019073:HT29 Cells; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
C587995:MIRN374 microRNA 374, human; D035683:MicroRNAs; D012333:RNA, Messenger; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D001761:Bleomycin; C494918:AKT1 protein, human; D051057:Proto-Oncogene Proteins c-akt