Deregulated
iron metabolism underlies the pathogenesis of many human
cancers. Recently, low expression of
ferroportin, which is the only identified non-
heme iron exporter, has been associated with significantly reduced overall survival in
multiple myeloma (MM); however, the altered
iron metabolism in MM biology remains unclear. In this study we demonstrated, by live cell imaging, that MM cells have increased intracellular
iron levels as compared with normal cells. In experiments to test the effect of
iron chelation on the growth of MM cells, we found that
deferasirox (DFX), an oral
iron chelator used to treat
iron overload in clinical practice, inhibits MM cell growth both in vivo and in vitro. Mechanistically, DFX was found to induce apoptosis of MM cells via the inhibition of
proline-rich tyrosine kinase 2 (Pyk2), which is known to promote
tumor growth in MM. Inhibition of Pyk2 is caused by the suppression of
reactive oxygen species, and leads to downregulation of the Wnt/β-
catenin signaling pathway. Taken together, our findings indicate that high levels of intracellular
iron, which might be due to low
ferroportin expression, play a role in MM pathophysiology. Therefore, DFX may provide a therapeutic option for MM that is driven by deregulated
iron homeostasis and/or Pyk2/Wnt signaling.