Membrane-associated Hsp72 from tumor-derived exosomes mediates STAT3-dependent immunosuppressive function of mouse and human myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSCs) have been identified in humans and mice as a population of immature myeloid cells with the ability to suppress T cell activation. They accumulate in tumor-bearing mice and humans and have been shown to contribute to cancer development. Here, we have isolated tumor-derived exosomes (TDEs) from mouse cell lines and shown that an interaction between TDE-associated Hsp72 and MDSCs determines the suppressive activity of the MDSCs via activation of Stat3. In addition, tumor-derived soluble factors triggered MDSC expansion via activation of Erk. TDE-associated Hsp72 triggered Stat3 activation in MDSCs in a TLR2/MyD88-dependent manner through autocrine production of IL-6.…

• AP
  Association pour la Recherche sur le Cancer
• IN
  Institut National de la Santé et de la Recherche Médicale
• FD
  Fondation de France