Table 2 Proteins/miRNAs in TEXs modulate the development and function of MDSCs

PGE2

Mammary carcinoma

TEXs with abundant PGE2 and TGF-β enhance the expansion and immunosuppression of MDSCs depending on MyD88 pathway by increasing the production of IL-6 and VEGF.

[114, 115]

TGF-β

Hsp72

Colon carcinoma /mammary carcinoma/lymphoma

Hsp72 expressed on the membrane of exosomes from tumor cells triggers STAT3 activation in MDSCs depending on the TLR2/MyD88 pathway through autocrine of IL-6.

[116]

IL-10

Multiple myeloma

Exosomal IL-10 and IL-16 from MM cells increase the accumulation and enhance the suppressive function of BM MDSCs by activating STAT3 pathway. MM exosomes can also reduce the survival of PMN-MDSCs, while increasing the survival of M-MDSCs.

[113, 117]

IL-16

miRNA-21

Hypoxia-induced glioma

miRNA-21 and miR-10a in exosomes from hypoxia-induced glioma promote the expansion and immunosuppression of MDSCs by targeting PTEN and RORα.

[118]

miR-10a

Oral squamous cell carcinoma

Hypoxic TEXs enhance the suppressive function of MDSCs and attenuate γδ T-cell activity in a miR-21/PTEN/PD-L1-axis-dependent manner.

[119]

miR-494-3p

Pancreatic ductal adenocarcinoma

PDAC-exosomes create an immunosuppressive myeloid cell background by increasing calcium fluxes through the transfer of SMAD4-related differentially expressed miR-1260a and miR-494-3p.

[120]

miR-1260a

miRNA-155

B- cell-derived chronic lymphocytic leukemia

High level of exosomal miRNA-155 from CLL cells can be uptaken by monocytes and induce IDO expressing MDSCs through STAT1 pathway.

[121]

miR-126-3p

Glioma/lung cancer

MDSCs internalizing TEXs display enhanced expression of suppressive molecules and differing miRNA profiles including miR-126-3p, miR-27b, miR-320, and miR-342-3p.

[122]

miR-27b

miR-320

miR-342-3p

miR-29a

Glioma

TEXs from glioma mediate the expansion and function of myeloid-derived suppressor cells through microRNA-29a/Hbp1 and microRNA-92a/Prkar1a pathways.

[123]

miR-92a