Fig. 8: Daratumumab-dependent ADCC against MM cells is increased by RNA Pol I inhibition.
From: Targeting RNA polymerase I to boost natural killer cell anticancer activity in multiple myeloma
A, B Cell surface expression of CD38 was assessed by flow cytometry on SKO-007(J3) and RPMI-8226 cells treated with CX-5461 or BMH-21 (200 and 400 nM) for 48 h. Histograms depict the mean fluorescence intensity (MFI) of CD38 after subtracting the MFI of the isotype control (*P < 0.05). C, D Cell surface binding of Daratumumab was evaluated by indirect flow cytometry on SKO-007(J3) and RPMI-8226 cells treated with CX-5461 or BMH-21 (200 and 400 nM) for 48 h. In these assays, Daratumumab was used as an unconjugated primary antibody, followed by staining with a FITC-conjugated anti-human secondary antibody. Histograms display the mean fluorescence intensity (MFI) after subtraction of the isotype control MFI (*P < 0.05). E Healthy donor PBMCs were incubated with SKO-007(J3) cells untreated or treated with CX-5461 or BMH-21 as described above. In this setting, anti-CD38/Daratumumab or isotype-control (0.5 µg/106) were added to target cells for 15 min at room temperature and then washed twice in complete medium. CD107a expression was evaluated on gated NK cells from PBMCs. Average percentage of CD107a positive cells was calculated based on three independent experiments (*P < 0.05). F Expression of CD16 and G CD38 on NK cells gated from PBMCs, untreated or treated with the indicated RNA Pol I inhibitor for 48 h. Histograms represent the average of at least three independent experiments (*P < 0.05).
