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

Abstract

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.