Pomalidomide enhances the maturation of dendritic cells derived from healthy donors and multiple myeloma patients

In vitro, 10 µM pomalidomide enhances the maturation of moDCs derived from both HDs and MM patients. Pomalidomide shows potential to be applied as a DC adjuvant for DC-based immunotherapy, such as the DC vaccine and DC cell therapy in MM.

MoDCs were generated by the incubation of monocytes from peripheral blood mononuclear cells (PBMCs) for 7 days in a medium consisting of 800 U/ml granulocyte-macrophage colony stimulating factor (GM-CSF), 500 U/ml interleukin-4 (IL-4), RPMI 1,640 medium, 5% human serum, 100 U/ml penicillin and 0.1 mg/ml streptomycin. Meanwhile, the incubation system was administrated with 10 µM pomalidomide or 1 × PBS as the control group. On the eighth day, cells were harvested and analyzed by flow cytometry. The CD80+CD86+ cell population in total cells was gated as moDCs in the FACS analyzing system. After that, the expression of CD40 and HLA-DR on moDCs was analyzed. Meanwhile, the supernatant from the incubation system was evaluated for the secretion of cytokines interleukin-12 (IL-12), tumor necrosis factor-α (TNF-α), and macrophage inflammatory protein 1α (MIP-1α) by enzyme-linked immunosorbent assay (ELISA).

To explore the effect of pomalidomide on the maturation of monocyte-derived dendritic cells (moDCs) from healthy donors (HDs) and multiple myeloma (MM) patients.

When analyzing all the HD-moDCs together (n = 15), pomalidomide significantly increased the mean fluorescence intensity (MFI) of CD40 expression and HLA-DR expression on moDCs compared with the control group (p = 0.003, p = 0.040). Meanwhile, the proportion of CD40+ moDCs and HLA-DR+ moDCs in total moDCs was significantly higher in the pomalidomide group than in the control group (p = 0.008, p = 0.032). When analyzing all MM patient-moDCs together (n = 11), pomalidomide significantly increased the MFI of CD40 expression and HLA-DR expression on moDCs compared with the control group (p = 0.047, p = 0.006). Meanwhile, the proportion of HLA-DR+ moDCs in total DCs was significantly higher in the pomalidomide group than in the control group (p < 0.001). Moreover, HD-moDCs (n = 8) treated with pomalidomide secreted 192% IL-12, 110% TNF-α, and 112% MIP-1α of the untreated moDCs (p = 0.020, p = 0.006, p = 0.055). However, when analyzing MM patient-moDCs (n = 10) together, the secretion of IL-12, TNF-α and MIP-1α from moDCs showed no significant difference between the pomalidomide group and the control group (p = 0.458, p = 0.377, p = 0.248).