Fig. 3

MDSCs enhance stemness of MMSCs via piRNA-823 up-regulation. a The expression of piRNA-823 in SP and NSP cells. SP and NSP cells were sorted from RPMI8226 and NCI-H929 cells. piRNA-823 expression was quantified using qRT-PCR. The results are presented as the mean values relative to controls ± SD; * P < 0.05. b The expression of piRNA-823 in sphere-forming cancer cells and parental RPMI8226 and NCI-H929 cells. * P < 0.05. c Effects of G-MDSCs on piRNA-823 expression in RPMI8226 cells. G-MDSCs from MM patients were co-cultured with RPMI8226 cells. piRNA-823 expression was quantified using qRT-PCR. The results from two patients (donors 2 and 4) analyzed in triplicate are shown. * P < 0.05. d Representative SP cells in each group were detected using flow cytometry. e G-MDSCs induced SP cell formation in MM, whereas piRNA-823 silencing markably abolished these effects. * P < 0.05. f Representative microscopy images of sphere cells in each group. g G-MDSCs promote sphere cells formation, whereas piRNA-823 silencing in MM cells markably reversed these effects. * P < 0.05. h The relevant expression levels of CSCs core genes were quantified in each group using qRT-PCR. The results from three experiments performed in triplicate are shown. The results are presented as the mean value relative to the controls ± SD; * P < 0.05. i Levels of Nanog, Oct-4, and Sox-2 proteins in each group were quantified using western blotting