Figure 6.

5,6-ECs display selective cytotoxic and apoptotic activities on human primary malignant plasma cells. (A) Cytotoxic activity of compounds was assessed on patient malignant cells of P1, P2 and P3 by MTT and for P4 cells by Trypan blue. For this, mononuclear cells (BMNCs) were purified from bone marrow and cell sorting using CD138 microbeads was assessed for P1-P4. CD138+ malignant plasma cells were cultured for 40 h in the absence or presence of 10–80 μg/mL of 5,6 α-EC or 5,6 β-EC. (B) Annexin V staining and flow sorting was used to detect the apoptotic population in sorted CD138+ cells of P1 after treatments with 10 or 40 µg/mL 5,6 α-EC or 5,6 β-EC. Flow cytometry profiles for all cell compartments (annexin V–/PI–, annexin V+/PI–, annexin V+/PI+ and annexin V-/PI+) with the corresponding percentages are presented. (C) BMNCs of P5 were treated with 10 µg/mL or 20 µg/mL of 5,6 α-EC or 5,6 β-EC for 24 h then labeled simultaneously for CD38, CD138 and annexin V. Annexin V+/CD38–/CD138– population was next evaluated by flow cytometry and presented in the histograms as means ±SD. (D) The effect of 5,6-ECs on HS-5 human non-tumor mesenchymal stromal cells was also evaluated using an MTT assay after 24 or 48 h of treatment. Data are presented as the means ±SD. No statistically significant difference between control and vehicle (EtOH) was noticed; ns, not significant.