. 2013 Jun 3;9(8):1654–1660. doi: 10.4161/hv.24917

Table 2. Approaches to overcome the immune suppression mediated by MDSCs.

Major goal	Approach	Result	Reference
Regulation of MDSC generation	Anti-c-kit mAb	Blockade of stem cell factor (SCF)-c-kit signaling and reduction of MDSC number	24
Regulation of MDSC generation	Tyrosine kinase inhibitor (sunitinib)	Blockade of vascular endothelial growth factor receptors (VEGFR), c-Kit, STAT3, etc., and reduction of MDSC number	25,26
Further differentiation of MDSC	All-trans-retinoic acid	MDSC differentiation into mature myeloid cells	27
Further differentiation of MDSC	Vitamin D3	CD34⁺ cell maturation	28,29
Depletion of MDSC	Gemcitabine	Elimination of MDSCs	30,31
	5-fluorouracil		32
	Anti-IL-6 receptor mAb		33
Prevention of MDSC recruitment to tumor	COX-2 inhibitor (celecoxib)	Downregulation of CCL2 production and decrease in MDSC recruitment	34
Prevention of MDSC recruitment to tumor	Inhibitor of CSF1R signaling (GW2580)	Decrease in monocytic MDSC recruitment	35
Inhibition of MDSC immunosuppressive function	PDE-5 inhibitor (sildenafil)	Inhibition of iNOS and/or ARG-1 activities	36
	COX-2 inhibitor (celecoxib)		37
	Nitroaspirin		38
	CpG ODNs	Reduction of suppressive function of Ly6G^high MDSC	39
	Triterpenoid	Inhibition of MDSC immune suppressive effect	40
	Rapamycin	Downregulation of ARG1, iNOS and Nox2 in MDSC	41
	α-galactosylceramide	Conversion of MDSC into nonsuppressor cells and increase in immunogenecity of MDSC	47,48