[Effects of sorafenib on proliferation and apoptosis of human multiple myeloma cell RPMI 8226].

This study was aimed to investigate the effects of sorafenib on proliferation and apoptosis of MM cell line RPMI-8226, and to explore the its potential anti-tumor mechanism. The inhibitory rate of multiple myeloma cell proliferation was tested by MTT. Transmission electron microscopy was used to observe morphological and ultrastructural changes of RPMI-8226 cells treated with sorafenib. The effects of sorafenib on the apoptosis and cell cycle of RPMI-8226 cells was detected by flow cytometry. The effects of sorafenib on the expression of caspase-3, BCL-2 and MCL-1 mRNA and protein were assayed by RT-PCR and Western blot respectively. The results showed that sorafenib (0-10.0 µmol/L) could obviously inhibit the proliferation of RPMI-8226 cells in time and dose-dependent manner. Flow cytometry results showed that sorafenib could induce apoptosis of RPMI-8226 cells, the difference was statistical significance (P < 0.05). Sorafenib mainly arrested RPMI-8226 cells in the G1 phase (P < 0.05). Typical apoptotic morphological and ultrastructural changes of MM cells could be observed under transmission electron microscope, Examination of cellular signaling pathways showed that sorafenib induced upregulation of cleaved-caspase-3 expression, and simultaneous downregulation of BCL-2 and MCL-1 expression. It is concluded that sorafenib displays anti-myeloma activity. Activating the death receptor pathway and arresting cell cycle may be two of the relatated mechanisms.