Sprouty2 regulates proliferation and survival of multiple myeloma by inhibiting activation of the ERK1/2 pathway in vitro and in vivo.

Multiple myeloma (MM) is an incurable disease, and its pathogenesis remains unclear. MicroRNA (miR)-21 was detected at a high level in MM and plays a key role in the pathogenesis of MM. However, Sprouty2 (spry2), a downstream target of miR-21, has low expression, and its mechanism in MM is unknown. We investigated whether spry2 could exert an antimyeloma effect and further studied the potential pathogenesis and progression of MM. To address the functional consequences of spry2, we assessed the expression levels of spry2 in several myeloma cell lines and detected low expression levels in MM cells. Overexpression of spry2 suppressed growth and colony formation ability and decreased the phosphorylation of extracellular signal-regulated kinases 1 and 2. Spry2 also decreased secretion of vascular endothelial growth factor and partially enhanced the sensitivity of MM cells to an inhibitor of mitogen-activated protein kinases 1 and 2. Additionally, spry2 inhibited the tumorigenesis and angiogenesis of MM cells in vivo. In summary, we report for the first time that spry2 can inhibit MM cell growth and survival with a concomitant reduction in phosphorylation of extracellular signal-regulated kinases 1 and 2 in vitro and in vivo.