Uroacitide-induced multiple myeloma cells of U266 by regulating the caspases

Objective To explore the effect of uroacitide on multiple myeloma (MM) cells of U266 and its mechanisms. Methods The inhibition ratio of different uroacitides (1.0, 2.0, 3.0, 4.0, 5.0 mg/g) on the growth of U266 cells was calculated by the methylthiazolyl tetrazolium (MTT) colorimetric assay. The apoptosis of U266 cells was observed by Hoechst33258 staining. Annexin-V/propidium iodide (PI) was used to detect the apoptosis rate of U266 cells with uroacitides at 6, 12, 24 h and cells without uroacitides. The Western-blotting method was used to test expressions of caspase 8, caspase 3 and their activators in U266 cells with uroacitides (4 mg/g) for 6, 12 and 24 h. Results The inhibition rate of U266 cells increased significantly as the concentration of uroacitides increased (F= 17.276, P<0.001). Condensed nuclei and apoptotic bodies were found in cells with uroacitides through Hoechst33258 fluorescence staining. Annexin-V/PI analysis showed that the apoptosis rate of cells with uroacitides at 6, 12, 24 h was much higher than that of cells without uroacitides [(5.53 ± 0.28)%, (9.43 ± 1.78)%, (21.50 ± 2.45)%, (3.03 ± 0.11)%, F= 12.242, P<0.001]. Meanwhile, the expressions of pro-caspase 8 and pro-caspase 3 decreased significantly (F= 18.241, P<0.001; F= 4.924, P= 0.005), and expressions of active-caspase 8, and active-caspase 3 increased (F=22.322, P<0.001; F= 6.213, P= 0.002) with prolonged time. Conclusion Uroacitides can inhibit the proliferation of U266 cells by influencing the caspase apoptosis pathway. Key words: Uroacitides; U266; Caspases; Multiple myeloma; Apoptosis