Bcl-xL is involved in uptake of L88 CD63-GFP cell-derived exosomes by MM cells. (A) Representative images uptake of L88 CD63-GFP PKH67-labeled exosomes by OPM2 or RPMI cells at 3 hours’ incubation. Ctrl, control. (B) Uptake of L88 CD63-GFP PKH67 labeled exosomes by OPM2 or RPMI cells at 1, 3, 6, or 24 hours of incubation. (C) Bcl-xL levels in exosomes derived from L88 cells transfected with shGFP (control) or shBcl-xL, as demonstrated by western blotting. Alix serves as a loading control. (D) Percentage of OPM2 or RPMI PKH67-positive cells, after 3 hours of incubation with L88 shGFP or L88shBcl-xL PKH67-labeled exosomes (mean ± SD, n = 3). ***P < .001. (E) Effect of ABT737 treatment in cell survival measured by PI staining in OPM2 (♦) and RPMI (▪) cell lines at 3 hours in different concentrations (1, 3, 5, and 10 μM) of the Bcl2/Bcl-xL inhibitor (mean ± SD, n = 3). (F) Percentage of OPM2 or RPMI PKH67-positive cells after 3 hours of incubation with L88 CD63-GFP PKH67-labeled exosomes that have been preincubated with the indicated concentrations of ABT737 (means ± SD, n = 3). ***P < .001.