Multiple myeloma (MM) is characterized by bone destruction due to increased
bone resorption and decreased bone formation.
Semaphorin 4D (CD100,
Sema4D) is expressed by osteoclasts, binds to its receptor Plexin-B1, and acts as a mediator of osteoclast-osteoblast interaction that ultimately inhibits osteoblastic bone formation. Preclinical data suggest that
Sema4D/
Plexin-B1 pathway is implicated in MM-induced
bone disease. However, there is no information on the role of
Sema4D in MM patients. Thus, we evaluated
Sema4D and Plexin-B1 in six myeloma cells lines in vitro; in the bone marrow plasma (BMP) and serum of 72 newly diagnosed symptomatic MM (NDMM) patients and in 25 healthy controls. Only one myeloma cell line produced high
Sema4D. BMP and circulating
Sema4D and Plexin-B1 levels were significantly higher in MM patients compared to controls (p < 0.01).
Sema4D correlated with serum
calcium levels (p < 0.001), increased
bone resorption (as assessed by CTX; p < 0.01), and ISS (p < 0.001). There was a trend for higher
Sema4D levels in patients with
osteolysis (p = 0.07), while patients with diffuse MRI pattern had higher BMP
Sema4D levels (p = 0.02). Our data suggest that
Sema4D is elevated in MM patients and correlate with adverse myeloma features and increased
bone resorption, providing a possible target for novel therapeutic approaches in MM.