Glioblastoma stem cell-derived exosomes induce M2 macrophages and PD-L1 expression on human monocytes.

Related Articles

Glioblastoma stem cell-derived exosomes induce M2 macrophages and PD-L1 expression on human monocytes.

Oncoimmunology. 2018;7(4):e1412909

Authors: Gabrusiewicz K, Li X, Wei J, Hashimoto Y, Marisetty AL, Ott M, Wang F, Hawke D, Yu J, Healy LM, Hossain A, Akers JC, Maiti SN, Yamashita S, Shimizu Y, Dunner K, Zal MA, Burks JK, Gumin J, Nwajei F, Rezavanian A, Zhou S, Rao G, Sawaya R, Fuller GN, Huse JT, Antel JP, Li S, Cooper L, Sulman EP, Chen C, Geula C, Kalluri R, Zal T, Heimberger AB

Abstract
Exosomes can mediate a dynamic method of communication between malignancies, including those sequestered in the central nervous system and the immune system. We sought to determine whether exosomes from glioblastoma (GBM)-derived stem cells (GSCs) can induce immunosuppression. We report that GSC-derived exosomes (GDEs) have a predilection for monocytes, the precursor to macrophages. The GDEs traverse the monocyte cytoplasm, cause a reorganization of the actin cytoskeleton, and skew monocytes toward the immune suppresive M2 phenotype, including programmed death-ligand 1 (PD-L1) expression. Mass spectrometry analysis demonstrated that the GDEs contain a variety of components, including members of the signal transducer and activator of transcription 3 (STAT3) pathway that functionally mediate this immune suppressive switch. Western blot analysis revealed that upregulation of PD-L1 in GSC exosome-treated monocytes and GBM-patient-infiltrating CD14+ cells predominantly correlates with increased phosphorylation of STAT3, and in some cases, with phosphorylated p70S6 kinase and Erk1/2. Cumulatively, these data indicate that GDEs are secreted GBM-released factors that are potent modulators of the GBM-associated immunosuppressive microenvironment.

PMID: 29632728 [PubMed]

https://ift.tt/2EDUw6v