Differences between samples were analyzed using the Student’s t test. Statistical significance was accepted at P < 0.05. Results PARP inhibitor trial miR-451 is significantly downregulated in human NSCLC tissues In this study, a stem-loop qRT-PCR assay was performed to determine the expression of miR-451 in 10 pairs of matched NSCLC and noncancerous lung tissue samples. As shown in Figure 1A, the expression levels of miR-451in NSCLC tissues were less than approximately 36.4% of those in noncancerous lung tissues. In addition, conventional STI571 RT-PCR assay was also performed to

analyze the expression of miR-451 in 2 pairs of matched NSCLC and noncancerous tissue samples. The gel electrophoresis of RT-PCR products confirmed the downregulation of miR-451 expression in NSCLC tissues (Figure 1B). Therefore, it was concluded that the downregulation of miR-451 might be involved in lung carcinogenesis. Figure 1 Detection of miR-451 expression in tissue samples. A. Quantitative RT-PCR analysis of miR-451 expression in 10 cases of NSCLC and corresponding noncancerous tissues. ** P < 0.01. N: noncancerous tissues; T: tumor tissues. B. Conventional stem-loop RT-PCR analysis GSI-IX ic50 of miR-451 expression in NSCLC and corresponding noncancerous tissues. Gel images of electrophoresis. U6 was used as an internal control. All experiments were performed in triplicate. The expression of miR-451

could be significantlu upregulated in A549 cells by pcDNA-GW/miR-45 To upregulate

the expression of miR-451 in NSCLC cell line (A549), pcDNA-GW/miR-451 was transfected and stable transfectants (A549/miR-451 or A549/miR-NC) were successfully established. As shown in Figure 2A, qRT-PCR assay showed that the relative level of miR-451 expression in A549/miR-451 could be significantly upregulated by 3.8-fold compared with that in mock A549 or A549/miR-NC cells (P < 0.05). The gel electrophoresis of RT-PCR products confirmed the upregulation of miR-451 expression in A549/miR-451 cells (Figure Urease 2B). Figure 2 Detection of miR-451 expression in mock or stably transfected A549 cells. A. Quantitative RT-PCR analysis of miR-451 expression in A549, A549/miR-NC or A549/miR-451 cells. B. Conventional stem-loop RT-PCR analysis of miR-451 expression in A549, A549/miR-NC or A549/miR-451 cells. Gel images of electrophoresis. U6 was used as an internal control. All experiments were performed in triplicate. Upregulation of miR-451 inhibits growth and enhances apoptosis of NSCLC cell line (A549) To analyze the effect of miR-451 expression on phenotypes of NSCLC cell line, we performed MTT, colony formation and flow cytometric assays. As shown in Figure 3A, A549/miR-451 cell line had a significant increase in cell viability compared with mock A549 or A549/miR-NC cell line (P < 0.05). The number of colonies formed from A549/miR-451 cells was significantly lower than that formed from mock A549 or A549/miR-NC cells (P < 0.05; Figure 3B).