Publication Date:
2015-12-03
Description:
Multiple myeloma (MM) is a malignancy of plasma cells and is characterized by unrestricted tumor cell growth in bone marrow (BM). MM causes destructive osteolytic lesions causing bone fracture, bone pain, hypercalcaemia, and nerve-compression, resulting from increased bone resorption and suppressed bone formation. Despite the introduction of agents to inhibit bone resorption, such as bisphosphonates, which prevent further bone loss, approaches to preventing osteoblast suppression and repair bone lesions are limited and there are no agents available clinically. The wnt/β-catenin pathway plays a critical role in the regulation of bone formation. Production of the soluble wnt antagonist dickkopf1 (Dkk1) by MM cells has been implicated in MM inhibition of bone formation. As such, Anti-Dkk1 treatment prevents bone disease in pre-clinical models of MM and is in early clinical development. However, Dkk1 is not expressed by all myeloma cells; hence only a proportion of patients may respond to anti-Dkk1 therapy. Sclerostin (Scl) is a soluble wnt antagonist whose expression, unlike Dkk1, is restricted to osteocytes; therefore Scl targeted agents may have less off target effects. Anti-Sclerostin (Anti-Scl) treatment increased bone formation and bone volume in experimental models of osteoporosis, and increased bone mineral density in phase II osteoporosis clinical trials. However, Anti-Scl treatment effects on myeloma bone disease are unknown. Further, cells of the BM such as osteoblasts have been implicated in the regulation of MM cell survival and growth. Thus, in the present study we explored the potential for Anti-Scl therapy to prevent MM induced bone loss and inhibit MM growth in both murine and human xenograft MM models. Female C57BLKalwRij mice (n=8) were injected i.v, with 5TGM1/eGFP murine MM cells (1×106) and female SCID/beige mice (n=10) were injected i.v. with MM1S/Luc/eGFP human MM cells (4 × 106). 24 hours later, naïve mice (without tumor cells) or mice bearing MM cells were treated with anti-sclerostin antibody (Anti-Scl) (100mg/kg i.v) or control antibody. Mice were sacrificed at day 21 (MM1S) or day 28 (5TGM1) and the effect of Anti-Scl on bone structure in the femora and vertebrae were determined by microCT analysis. The effect of Anti-Scl on MM burden was determined by bioluminescent imaging (BLI) performed twice weekly from week 1 using a Xenogen IVIS system, whereas MM burden in 5TGM1/eGFP bearing mice was examined by FACS analysis. Anti-Scl treatment in naïve C57BLKalwRij mice increased trabecular bone volume fraction (BV/TV, 39%, p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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