Fig. 2

G-MDSCs enhance stemness of MMSCs in vitro. a Correlation between the proportions of G-MDSCs and SP cells in primary MM cells, as analyzed using flow cytometer (n = 12, R = 0.69, P = 0.01). b Representative SP cells shown using flow cytometer. Verapamil was used as negative control. c and d G-MDSCs stimulated the formation of SP cells in RPMI8226 and NCI-H929 cultures. G-MDSCs from five MM patients were co-cultured with RPMI8226 and NCI-H929 cells for 48 h. Then, the percentages of SP cells in MM cell lines were determined using flow cytometer. The results are presented as means ± SEM. * P < 0.05. e and f G-MDSCs co-culture increased MM sphere formation. RPMI8226 and NCI-H929 cells were cultured with G-MDSCs under sphere-forming conditions. Numbers of spheres are presented as means ± SD. * P < 0.05. g Human G-MDSCs stimulated the expression of CSCs core gene. RPMI8226 and NCI-H929 cells were co-cultured with primary G-MDSCs in Transwells for 48 h. The expression levels of CSCs core genes were quantified using qRT-PCR. The results are presented as the mean relative expression levels ± SD. h Levels of the Nanog, Oct-4, and Sox-2 proteins in each group were quantified using Western blotting