Fig. 2

Clinical and biological validation of WDR26 and MTF2 in myeloma. a WDR26 (top) and MTF2 (bottom) expression levels (GSE 2658 and 5900 datasets) in bone marrow plasma cells from healthy individuals (BMPC, n = 22) or patients with monoclonal gammopathy of undetermined significance (MGUS, n = 44), smoldering myeloma (SMM, n = 12) or frank myeloma (MM, n = 559). MM data are from GSE2658, all others from GSE5900. b Comparison of mean mRNA levels of WDR26 (top) or MTF2 (bottom) in patients with standard-risk myeloma (SR, n = 690) or high-risk myeloma (HR, n = 287), using data from the Multiple Myeloma DREAM Challenge study. c Overall survival (OS) of patients with myeloma in the MMRF CoMMpass study stratified according to WDR26 (top) or MTF2 (bottom) message levels in malignant plasma cells. The top quartile (n = 194, red) and bottom quartile (n = 194, blue) are compared. HR, hazard ratio. d Western analysis of WDR26 (left) or MTF2 (right) in normal (N) or gene-targeted (KO) myeloma cell lines, OPM2, H929 and MM1.S. KO protocols including gRNA sequences are available upon request. e Growth of HMCLs in bulk suspension culture. Cells deficient in WDR26 (blue) or MTF2 (red) are compared to parental cells (black) used as control. f Clonogenic growth of OPM2 (top), H929 (center) and MM1.S cells (bottom) lacking WDR26 (blue) or MTF2 (red) or containing the proteins (black). Representative images of soft-agar plates are shown to the left. The bar diagram to the right displays mean colony numbers ± SD based on three independent experiments. g Representative flow cytometric scatter plots of apoptotic death (red, labeled rectangles) of WDR26 or MTF2 deficient HMCLs compared to normal cells. h Mean values of apoptosis based on three independent measurements. Standard deviations are indicated by short vertical lines (***p < 0.001). i Bioluminescence images of NSG mice on days 10, 20, 30 and 40 following challenge with OPM2 cells (upper panel) or H929 cells (lower panel) deficient of WDR26 (center column) or MTF2 (right column). Parental cells proficient of these proteins served as control (left column). j Quantitative analysis of bioluminescence signal strength in mice from h. k Kaplan–Meier survival curves of mice depicted in h. Statistical comparison relied on log rank analysis. l Flow cytometry histogram distinguishing GFP-expressing tumor cells in the bone marrow of xenotransplanted mice from h (smaller peaks, right) from bone marrow cells not expressing GFP (larger peaks, left). m Abundance of GFP-expressing tumor cells in the bone marrow of mice from h