Objective To study the influence of miRNA-125b over-expression on proliferation and invasion ability of lung cancer A549 cells and its mechanism.Methods A549 cells were divided into 3 groups:miRNA-125b group(transfected with miRNA-125b mimics),NC group(transfected with NC mimics) and blank group(same volume of GIBCO serum mixed with transfection agent).The transfection and expression efficiency of miRNA-125b was detected with Q-PCR,the proliferation ability was detected with MTT,and the invasion ability was detected with the transwell chamber test.The expression level of BMF in A549 cells was detected with Western blot.Results Compared with the blank group,the expression level of miRNA-125b,proliferation ability and invasion ability in the miRNA-125b group were increased(P＜0.05);while the above indexes in the NC group demonstrated no significant change(P＞0.05).Compared with the blank group,the expression level of BMF in the miRNA-125b group was decreased (P＜0.05);while which in the NC group had no significant change(P＞0.05).Conclusion miRNA-125b can promote the proliferation and invasion ability of A549 cells via inhibiting the expression of BMF.

Objective    To detect the difference of periostin expression in small cell lung cancer (SCLC) cell, and explore its effect on chemoresistance of SCLC patients. Methods    The expression of periostin in mRNA and protein was detected by RT-PCR and Western blot analysis in SCLC H69 and multidrug resistant strain H69AR. The expression of periostin was up-regulated by recombinant plasmid-periostin in H69 cell. The survival rate in the transfected group was different from that of the negative control group and uninterrupted group. Results    The expression of periostin mRNA and protein in the sensitive strain H69 was lower than that of the multidrug resistant strain H69AR (P<0.05). The recombinant periostin-plasmid was transfected into H69 cells and at the same concentration of chemotherapeutic drugs (cisplatin, etoposide) the survival rate increased significantly (P<0.05). The positive expression rate of periostin in SCLC tissues was 67.44%, and the sensitivity of the chemotherapy group was lower than that of the drug resistant group (P<0.05). Conclusion    The expression of periostin in SCLC cell H69 is significantly lower than that of the multidrug resistant strain H69AR and overexpression of periostin increases resistance of the sensitive strain H69 and hence periostin may be involved in SCLC chemoresistance.