BTZ treatment affects lipid composition in parental and BTZ-resistant MM cells differently. (A) Cells from indicated parental MM cell lines were treated or not with the 50% inhibitory concentration amounts of BTZ for 16 hours (MM.1S, 6 nM; RPMI8226, 3 nM; KMS11, 6 nM; and ARH-77, 8 nM) followed by the assessment of cell viability via trypan blue exclusion assay. No increase in cell death was detected in BTZ-treated cells (data not shown). Treated and untreated cells were subjected to lipidomic analysis in independent triplicates. Mean ratios of the levels of individual lipids between BTZ-treated and untreated MM cells were calculated and plotted as heatmaps for lipid classes designated as in Figure 3. The heatmaps consist of individual lipid species ratios. A scale for the number of individual lipid species ratios is shown on the right. Only lipid classes with >20 species are shown. (B) Cells from indicated parental and BTZ-resistant MM cell lines were subjected to untargeted lipidomic analysis in independent triplicates. Raw values of each lipid molecule (each row) were transformed as z scores and plotted as heatmaps, with red representing the highest value and blue representing the lowest value. (C) Cells from indicated parental and BTZ-resistant MM cell lines were subjected to lipidomic analysis in independent triplicates. Mean ratios of the levels of individual lipids between BTZ-resistant and parental MM cells were calculated and plotted as heatmaps for lipid classes designated as in Figure 3. Only lipid classes with >20 species per lipid class are shown. The heatmaps consist of individual lipid species ratios. A scale for the number of individual lipid species ratios is shown on the right.