Exosomes Derived from RM-1 Cells Promote the Recruitment of MDSCs into Tumor Microenvironment by Upregulating CXCR4 via TLR2/NF- Pathway

Figure 4

CXCR4 expression was increased in MDSCs treated with exosomes both in vivo and vitro, which mediated by activating NF- and engaging TLR2. (a), (b) MDSCs cocultured with exosomes for 24 h and the expression of CXCR4 in MDSCs detected by Western blot. Exosomes and PBS 20 ug were injected into normal mice via the tail vein 3 times per week for 2 weeks, respectively; single cell suspensions from bone marrow ((c), (d)) and spleen ((c), (e)) were prepared one day after the final injection and then stained by anti-CD11b-FITC, anti-Gr-1-PE, and anti-CD184-APC antibodies to detect CXCR4 positive expression rate in population of CD11b + Gr-1 + MDSCs by flow cytometry. MDSCs were cocultured with PBS, exosomes, C29 plus exosomes, and C29 for 24 h; the expression levels of TLR2 ((f), (g)), p65, p-p65 (i), and CXCR4 (h) in each group were measured by Western blot. β-Actin served as the control. and compared with the control group.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)