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Abstract LB-091: Inhibition of Siglec-15 prevents bone loss in a mouse model of multiple myeloma
Abstract Multiple myeloma (MM) is a B-cell malignancy associated with infiltration and growth of plasma cells in the bone marrow resulting in end-organ damage including devastating osteolytic bone disease. We examined the ability of 25B2, an antibody targeting Siglec-15, to prevent bone loss in the...
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| Published in: | Cancer research (Chicago, Ill.) Ill.), 2016-07, Vol.76 (14_Supplement), p.LB-091-LB-091 |
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| Main Authors: | , , , |
| Format: | Article |
| Language: | English |
| Online Access: | Get full text |
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| Summary: | Abstract
Multiple myeloma (MM) is a B-cell malignancy associated with infiltration and growth of plasma cells in the bone marrow resulting in end-organ damage including devastating osteolytic bone disease. We examined the ability of 25B2, an antibody targeting Siglec-15, to prevent bone loss in the 5T2MM syngeneic model of MM. C57BlKaLwRij male mice (n = 10/group) were injected with 5T2MM cells and 24h later treated for 12 weeks with the PBS, 25B2 (10 mg/kg, q3d), bortezomib (0.7 mg/kg, q3d) or a combination of 25B2 and bortezomib. 25B2 treatment caused a 3.7-, 5.4- and 1.2-fold increase in bone volume (%BV/TV) compared to PBS-treated mice in the tibia, femur and lumbar vertebra (LV), respectively. Increases in bone volume were also seen with bortezomib with 3.1-, 4.1- and 1.4-fold increases in the tibia, femur and LV, respectively. Combination of the two agents further increased%BV/TV by 6.9-, 10.5- and 1.5-fold in the tibia, femur and LV, respectively, when compared to the PBS treated mice. All of the changes were statistically significant with the exception of those in the LV. Unlike bortezomib treatment, which inhibits the growth of 5T2MM cells in this model, there was no direct effect of 25B2 on tumor burden in 5T2MM mice when the percentage of plasmacytosis and the serum paraprotein levels were measured. However, 25B2 caused a significant decrease in the number of bone lesions by 49.5%. The number of lesions in the bortezomib group decreased by 71.7%, but there was no significant difference between the 25B2 and bortezomib groups. The number of lesions decreased by 89.4% in the combination group. Consistent with the mechanism of action of Siglec-15 antibodies, osteoclasts were rendered inactive, however cross-talk with bone-forming osteoblasts was likely maintained. This unique mechanism of action would be particularly appropriate for MM, where osteolytic disease is not only the result of increased osteoclast activity but also decreased osteoblast-mediated bone formation. The 5T2MM model is one of the most representative of the human pathology and therefore, the effect observed in response to the Siglec-15 antibody holds the promise that such a treatment in MM patients could provide benefit and further delay skeletal related events.
Citation Format: Gilles B. Tremblay, Anna Moraitis, Karin Vanderkerken, Mario Filion. Inhibition of Siglec-15 prevents bone loss in a mouse model of multiple myeloma. [abstract]. In: Proceedings of the 107th Annual Meeting |
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| ISSN: | 0008-5472 1538-7445 |
| DOI: | 10.1158/1538-7445.AM2016-LB-091 |