The effects of Selinexor and bone morphogenetic protein 6 on multiple myeloma

Sammanfattning

Multiple myeloma is a complex form of cancer that originates from the bone marrow, caused by uncontrolled proliferation of plasma cells. It causes bone lesions, kidney failure and weakening of the immune system, and while there are multiple treatments, patients eventually become resistant and relapse. Research in myeloma cell survival and progression mechanisms is important to find new potential targets for treatment. Myeloma cells often overexpress Exportin-1 (XPO1), a nuclear export protein for many tumor suppressive proteins. Selinexor is a new drug that specifically inhibits XPO1 by binding irreversibly to it. Bone morphogenetic protein 6 (BMP6) stimulates the BMP pathway, which increases phosphorylation and thus activation of the co-transcription factor SMAD1/5, and has previously been seen to induce apoptosis and inhibit cell-growth in myeloma cells. In this project, myeloma cells were treated with Selinexor and BMP6 separately and together, to investigate how the treatments affect subcellular localization of the proteins XPO1, phospho-SMAD1/5, SMAD4, which transports phospho-SMAD1/5 to the nucleus, and yes-associated protein (YAP). Cells were fractionated into cytoplasmic and nuclear fractions, proteins separated by gel electrophoresis and analyzed by western blotting, where the proteins were visualized using a chemiluminescent substrate for HRP-conjugated antibodies. The results show significant increase in cytoplasmic phospho-SMAD1/5 when treated with BMP6, while nuclear phospho-SMAD1/5 was significantly higher when treated with both BMP6 and Selinexor. Nuclear SMAD4 was significantly increased in cells treated with Selinexor alone, and none of the treatments significantly affected XPO1 localization.