Figure 2: Microarray analysis of human osteosarcoma cell lines. (a) Principle component analysis (PCA). Three PCA coordinates describe 56% of the total data variation (PC1, 8.8%; PC2, 18.1%; PC3, 29.1%). Red, B143; blue, SJSA; green, U2OS. (b) Unsupervised hierarchical cluster analysis. Heatmap representation of differentially expressed genes in U2OS, SJSA, and B143 cells treated for 21 days with 15 nM LBH589 or DMSO. Each column represents a distinct sample, and each row represents an individual gene. Level of expression is denoted by colour (blue, low; red, high). (c) Heatmap representation of genes enriched in functional groups associated with osteogenesis, chondrogenesis, and adipogenesis. Each column represents a distinct sample. (d) Quantitative real-time PCR of U2OS cells cultured for 21 days in the presence of 15 nM LBH589 for expression of osteoblast differentiation markers. *, **, and ***. (e) Analysis of chondrocyte and adipocyte differentiations of human osteosarcoma cells treated for 21 days in 15 nM LBH589 by Alcian Blue staining, a marker of cartilage extracellular matrix, phase contrast microscopy, and the triglyceride marker, Oil Red O. Scale bar = 250 μm.