(B) miRNAs that are differentially expressed between NSCLCs and HBECs. (C) miRNAs that are differentially expressed between SCLCs and NSCLCs. Yellow indicates AZD5363 nmr relative over-expression, Selleckchem Bafilomycin A1 and blue indicates relative under-expression. The miRNA expression profile changes progressively from normal cells to NSCLC to SCLC cells Interestingly, the above analysis indicates that more miRNAs are differentially expressed between SCLC cell lines and HBECs than between NSCLC cell lines and HBECs. In addition, the two miRNAs that are significantly differentially expressed in NSCLCs relative to HBECs
are included in the group of 30 miRNAs identified as differentially expressed in SCLCs relative to HBECS, as shown in Figure 2A. This suggests a possible pathological relationship between the three groups of cell lines. To examine this relationship, we applied linear GSK872 manufacturer discriminant analysis to the three groups of cell lines based on the 41 miRNAs that are identified as significantly differentially expressed as shown in Figure 2. As shown in Figure 3, 88% of the between-group variance is explained by the first discriminant function with miRNA expression placing NSCLCs between HBECs and SCLC lung tumor
cells, suggesting a progressive change in expression from HBECs to NSCLC to SCLC cell lines. Figure 3 A sequential change in expression profile from normal cells to NSCLC cells to SCLC cells. Linear discriminant analysis places the NSCLCs between SCLCs and HBECs, suggesting a progression from HBECs to NSCLC to SCLC cell lines. The plot is a projection of the multi-dimensional space into two dimensions described by two linear discriminants, in which the Thymidylate synthase individual points represent the cell lines
and the classifiers are indicated by black lines. 88% of the between-class variance is explained by the first discriminant function (displayed along the x-axis of the plot). To examine this relationship at the level of individual microRNAs, we applied the Jonckheere-Terpstra test for ordered means to the expression levels of each miRNA in the three groups. This allowed us to assess whether or not the expression trend followed the order SCLC, NSCLC, HBEC. As shown in Table 2, of the 26 miRNAs that are over-expressed in SCLC cell lines relative to non-SCLC cell lines, all 26 (100%) show ordered expression at a significance level of 0.05, with 24 (92%) showing strict ordering of mean expression levels with SCLC > NSCLC > HBEC. Of the 15 miRNAs that are under-expressed in SCLC cell lines relative to non-SCLCs, 14 (93%) show ordered expression at a significance level of 0.05, with 10 (66%) showing strict ordering of mean expression levels with SCLC < NSCLC < HBEC. These results suggest that expression of a set of miRNA changes progressively from normal cells to NSCLC tumor cells to SCLC tumor cells.