Bone marrow neutrophils regulate multiple myeloma by releasing DNA

Development of Multiple Myeloma is associated with an accumulation of myeloid derived suppressor cells (MDSCs ) - cells that are morphologically and phenotypically similar to neutrophils (PMN-MDSC) and monocytes (M-MDSC), but are distinct in their functional and biochemical characteristics as well as in their ability to suppress immune responses. In our study, we found that both neutrophils and PMN-MDSCs equally promoted MM survival and decreased MM cell sensitivity to chemotherapy. Therefore, we used a microarray to elucidate the mechanism of the protective effect of neutrophils on myeloma cells. DP42 murine myeloma cells were cultured alone or together with mouse B-cells (control) or neutrophils for 24 hours. The cells were subsequently separated using FACs and RNA was extracted using Trizol