Molecular and cellular characterization of MDSC differentiated from the bone marrow of Balb/c mice with tumor conditioned media or tumor conditioned media and antagonists for CCR1 and CCR5

Tumor derived factors can promote the differentiation of hematopoietic precursors into suppressive myeloid derived suppressor cells however, the molecular pathways that regulate this differentiation are not fully disclosed. In this study we identified a pathway by which tumor derived factors induce the expression of CCL3 and CCL4 from early HSPCs that autocrinally bind to CCR1 and CCR5 mediate the differentiation of BM cells into suppressive and protumoral cells. Inhibition of CCR1 and CCR5 is sufficient to prevent MDSC differentiation and restore the generation of myeloid cells with a tumoricidal function. ACK lysed BM cells from Balb/c mice were cultured for 4 hours with RPMI, RPMI with tumor derived factors from 4T1 tumors, or RPMI with tumor derived factors from 4T1 tumors and antagonists against CCR1 and CCR5. Cells were stored in Trizol for RNA extraction RNA extraction was carry on with miRNAeasy mini kit from Quiagen; RNA QC was assessed by Agilent BioAnalyzer 6000 and samples were analyzed with Affymetrix mouse... 2.0 ST array