Objective To investigate the effect of AP-2α on the chemoresistance to oxaliplatin of colorectal carcinoma cell and its related mechanism.Methods Plasmid of GV102-AP-2α-RNAi (experimental group) and control plasmid GV102-NC (negative control group) were transfected into HCT-116 using Lipofectamine 2000 respectively.The AP-2α expression levels of mRNA and protein of experimental group,control group and HCT-116 blank group were detected by qRT-PCR and Western blot.Cell proliferation assay was performed using the CCK-8 and the apoptosis assays were preformed with Annexin V-PE Apoptosis Kit.Results The AP-2α expression levels of mRNA and protein both decreased after transfection of AP-2α-RNAi plasmid,moreover,the effect produced by subsequence 1 was the most significant.After treatment by oxaliplatin,AP-2α protein levels increased with time while mRNA did not change significantly.Western blot results suggested that the level of AP-2α protein in experimental group which was maintained in oxaliplatin was lower than the negative control group.CCK-8 results suggested that cell proliferation ability was significantly higher for the experimental group maintained in oxaliplatin [(88±3) ％] than the negative control group maintained in oxaliplatin [(57±3) ％] and the blank group maintained in oxaliplatin [(73t4) ％].Flow cytometry showed that the apoptosis rate of the experimental group maintained in oxaliplatin [(15.07±1.20) ％] was lower than the control group maintained in oxaliplatin [(24.93±0.90) ％] and the blank group maintained in oxaliplatin [(23.71±1.32) ％].Conclusion AP-2α may be related to the sensitivity of colon cancer cells to oxaliplatin.

Objective To investigate the impact of miR-200c overexpression on colon cancer cell proliferation ability and the related mechanism.Methods MicroRNAs which may combined with the transcription factor AP-2α were screened and forecasted by the bioinformatics database,while its eukaryotic expression plasmids and specific inhibitor were synthesized.Plasmids PEZX-miR-200c,PEZX-NC,pmirGLO-AP-2α3'UTR,pmir-GLO and the specific inhibitors miR-67-inhibtor,miR-200c-inhibitor were transfected in vitro into colon cancer HCT-116 and SW480 cells and the HEK293T cell by Lipofectamine2000.The expression of AP-2α mRNA and protein in colon cancer cells was analyzed by qRT-PCR,Westem blot and immunocytochemical staining.CCK-8 assay and flow cytometry were adopted to observe the effect of miR-200c on colon cancer cells proliferation and apoptosis.Dual-Luciferase assay experiments were performed to observe the relative luciferase activity induced by miR-200c.Results The proliferation activity was significantly decreased in anti-miR-200c/SW480 group,while in PEZX-miR-200c/HCT-116 group,it was higher than that in PEZX-NC/HCT-116 group.The apoptosis ability was significantly increased in anti-miR-200c/SW480 group [(78±0.7) ％ vs (66±1.1) ％,P ＜ 0.05].The expression of AP-2o both in mRNA and protein levels was decreased in PEZX-miR-200c/HCT-116 group,while the protein level was increased in Anti-miR-200c/SW480 group.The relative luciferase activity inhibited by miR-200c was decreased in HEK-293T cells transfected with PEZX-miR-200c and pmir-GLO-AP-2α3' UTR (0.51±0.09 vs 0.98±0.04,P ＜ 0.01).Conclusion MicroRNA-200c could promote cell proliferation ability by targeting transcriptional factor AP-2α in human colorectal cancer cells.