Essential role of miRNAs in orchestrating the biology of the tumor microenvironment

Table 1 Actions of exosomal miRNAs exchanged between cells of the TME

Angiogenesis:
miRNA	Cell of origin	Accepting cell	Pathway/target	Effect on TME	Ref.
miR-135b	Multiple myeloma	Endothelial cells	HIF-1/FIH-1	↑angiogenesis	[11]
miR-494	Lung cancer	Endothelial cells	PTEN/AKT/eNOS	↑angiogenesis	[10]
miR-503	Endothelial cells	Breast cancer	Cyclin D2 and D3	↓Tumor growth and invasion	[22]
miR-1246	Colorectal cancer	Endothelial Cells	PML/Smad 1/5/8	↑ Growth & migration	[9]
Stromal compartment:
miR-105	Breast cancer	Endothelial cells	ZO-1	↓Tight junctions ↑Metastatic progression	[68]
miR-202-3p	CLL	Stromal cells	c-fos/ATM	↑Tumor growth	[53]
Immune system:
miR-29a	NSCLC	TAM	TLR8/NF-κB	↑Growth & metastasis	[75]
miR-21	NSCLC	TAM	TLR8/NF-κB	↑Growth & metastasis	[75]
miR-21	NBL	TAM	TLR8/NF-κB	↑miR-155	[76]
miR-155	TAM	NBL	TERF1	↑ Drug resistance	[76]
miR-23a	Hypoxic tumor derived	NK cells	CD107a	↓ NK cell response	[95]
miR-210	Hypoxic tumor derived	NK cells	CD107a	↓ NK cell response	[95]
miR-214	Tumor cells (various)	Regulatory T cells	PTEN	↑Immunosuppression	[96]
miR-223	TAM	Breast cancer	Mef2c/β-catenin	↑ Invasion	[82]

Abbreviations: TAMs Tumor Associated Macrophages, CLL chronic lymphocytic leukemia, NSCLC non-small cell lung cancer, NBL Neuroblastoma

ISSN: 1476-4598