Fig. 8

Mechanism of MDSC-Exo in prostate cancer progression by regulating circMID1. MDSC-derived exosomes (MDSC-Exo) accelerated PCa cell proliferation, migration, and invasion, while circMID1 (hsa_circ_0007718) expression was elevated in PCa cells treated with MDSC-Exo. Exosomes secreted from MDSCs could transfer S100A9 to prostate cancer cells, upregulating the expression circMID1 by inhibiting DHX9. MDSC-derived exosomal S100A9 increased circMID1 expression to sponge miR-506-3p, leading to increased MID1 expression and accelerated tumor progression