Objective: To investigate the effect of parthenolide (PTL) on human multiple myeloma (MM) cells in vitro and its mechanism.
Methods: Human MM cells of the line PRMI8266 were cultured and treated with PTL of the concentrations of 1, 2.5, 5, 7.5, and 10 micromol/L for 24, 48, or 72 hours. MM cells treated with DMSO were used as control group. The optical density was measured so as to draw a growth curve. The cell viability was detected by MTT and trypan-blue exclusion. The apoptosis was detected by flow cytometry. AO/EB staining and Wright-Giemsa staining were used to observe the morphological changes of the cells by fluorescence microscope and light microscope respectively. The caspase-3 activity was evaluated by BD ApoAlert Caspase Colorimetric Assay Kit.
Results: PTL significantly inhibited the proliferation and viability of the MM cells time and dose-dependently (all P < 0.01), and significantly induced the cell apoptosis after 48 h in a dose-dependent manner (P < 0.01). The early cell apoptosis rates for PTL of the concentrations of 2, 5 and 10 micromol/L were 17.1% +/- 2.6%, 33.6% +/- 3.8%, and 40.9% +/- 3.1% respectively, all significantly higher than that of the control group (5.6% +/- 1.2%, all P < 0.01). The MM cells treated with PTL of the concentration of 5 micromol/L for 48 h showed typical cell apoptotic features. The caspase-3 activity of the MM cells was enhanced significantly by PTL in a time and dose-dependent manner (all P < 0.01).
Conclusion: This first report of anti-proliferation and apoptosis induction effects of PTL on MM cells shows that able to significantly inhibit the proliferation and induce the apoptosis of MM cells and enhance the caspase-3 activity, PTL may be a potentially useful drug for treatment of MM.