Objective To explore the function of p53 on regulating the expression of miR-148b in lung cancer cell line PC-9 and its corresponding molecular mechanism and the impact on cell proliferation. Methods Transient transfection of p53 eukaryotic expressing plasmids into lung cancer cell line PC-9 was performed to establish a cell model over-expressing p53. RT-PCR was used to explicit the impact of p53 on the expression of miR-148b. A reporter vector containing miR-148b promoter was used to investigate the function of p53 on regulating the transcription of miR-148b. Low-expressing miR-148b by transfecting its specific inhibitors , a CCK-8 assay was performed to explore the influence of miR-148b on the lung cancer cell proliferation inhibited by p53. Results Over-expression of p53 promoted miR-148b expression in lung cancer cell line PC-9. P53 could increase the luciferase activity driven by miR-148b promoters. Knockdown of miR-148b attenuated the impact of p53 on inhibiting the proliferation of PC-9 cells. Conclusion P53 inhibits the proliferation of lung cancer cell line PC-9 partially depending on miR-148b.

Objective : To explore the feasibility of the bilayer chitosan barrier membrane loaded with tannic acid (CS@ TA) for guided bone regeneration by exploring the reactive oxygen species (ROS) scavenging ability , bio- compatibility , and antibacterial properties . Methods : The single-layer chitosan (CS) film was prepared by self-evaporation , and the double-layer CS film was prepared by directional freezing and freeze-drying , and its microstruc- ture was ob served by scanning electron microscope . The prepared CS bilayer membrane was grafted with tannic acid (TA) in different proportions , and the interaction between TA and CS bilayer membrane was analyzed by Fourier infrared spectrometer (FITR) . The ROS scavenging ability was tested by 1 , 1 -diphenyl-2 -picrylhydrazyl (DPPH) , and the double-layer membrane of loading TA scavenging efficiency of more than 90% was selected to continue the follow-up experiment. CCK-8 assay and lived dead staining were used to evaluate the survival rate of cell in each groups . MC3T3 -E1 cells was adhesion the CS@ TA barrier film for studying by SEM . Colony counting was performed to test its antibacterial performance against Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus ) . Results : One side was the smooth , dense while other side was rough , loose and porous , with a longitudinal ordered porous structure in cross-section of the double-layer membrane of CS@ TA . With the addition of TA , the ROS scavenging ability of the double-layer membrane first increased rapidly and then stabilized slowly. The results of CCK-8 and lived and dead cells staining showed that excessive TA addition significantly affected the biocompati- bility of the double-layer membrane . The counting results of bacterial dilution coating showed that compared with the double-layer membrane without TA loading , the double-layer membrane had certain antibacterial ability against E. coli and S. aureus when the appropriate amount of TA was added . Conclusion Thus the double-layer with ap- propriate TA loading has strong ROS scavenging ability , good biological performance , and certain antibacterial abil- ity for E. coli and S. aureus .