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Genetic deletion of Sost or pharmacological inhibition of sclerostin prevent multiple myeloma-induced bone disease without affecting tumor growth.

ABSTRACT: Multiple myeloma (MM) causes lytic bone lesions due to increased bone resorption and concomitant marked suppression of bone formation. Sclerostin (Scl), an osteocyte-derived inhibitor of Wnt/?-catenin signaling, is elevated in MM patient sera and increased in osteocytes in MM-bearing mice. We show here that genetic deletion of Sost, the gene encoding Scl, prevented MM-induced bone disease in an immune-deficient mouse model of early MM, and that administration of anti-Scl antibody (Scl-Ab) increased bone mass and decreases osteolysis in immune-competent mice with established MM. Sost/Scl inhibition increased osteoblast numbers, stimulated new bone formation and decreased osteoclast number in MM-colonized bone. Further, Sost/Scl inhibition did not affect tumor growth in vivo or anti-myeloma drug efficacy in vitro. These results identify the osteocyte as a major contributor to the deleterious effects of MM in bone and osteocyte-derived Scl as a promising target for the treatment of established MM-induced bone disease. Further, Scl did not interfere with efficacy of chemotherapy for MM, suggesting that combined treatment with anti-myeloma drugs and Scl-Ab should effectively control MM growth and bone disease, providing new avenues to effectively control MM and bone disease in patients with active MM.

SUBMITTER: Delgado-Calle J

PROVIDER: S-EPMC5699973 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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Genetic deletion of Sost or pharmacological inhibition of sclerostin prevent multiple myeloma-induced bone disease without affecting tumor growth.

Delgado-Calle J J Anderson J J Cregor M D MD Condon K W KW Kuhstoss S A SA Plotkin L I LI Bellido T T Roodman G D GD

Leukemia 20170522 12

Multiple myeloma (MM) causes lytic bone lesions due to increased bone resorption and concomitant marked suppression of bone formation. Sclerostin (Scl), an osteocyte-derived inhibitor of Wnt/β-catenin signaling, is elevated in MM patient sera and increased in osteocytes in MM-bearing mice. We show here that genetic deletion of Sost, the gene encoding Scl, prevented MM-induced bone disease in an immune-deficient mouse model of early MM, and that administration of anti-Scl antibody (Scl-Ab) increa ...[more]

PMID: 28529307

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Project description:Patients with anterior cruciate ligament (ACL) rupture are two times as likely to develop posttraumatic osteoarthritis (PTOA). Annually, there are ?900,000 knee injuries in the United States, which account for ?12% of all osteoarthritis (OA) cases. PTOA leads to reduced physical activity, deconditioning of the musculoskeletal system, and in severe cases requires joint replacement to restore function. Therefore, treatments that would prevent cartilage degradation post-injury would provide attractive alternatives to surgery. Sclerostin (Sost), a Wnt antagonist and a potent negative regulator of bone formation, has recently been implicated in regulating chondrocyte function in OA. To determine whether elevated levels of Sost play a protective role in PTOA, we examined the progression of OA using a noninvasive tibial compression overload model in SOST transgenic (SOSTTG ) and knockout (Sost-/- ) mice. Here we report that SOSTTG mice develop moderate OA and display significantly less advanced PTOA phenotype at 16 weeks post-injury compared with wild-type (WT) controls and Sost-/- . In addition, SOSTTG built ?50% and ?65% less osteophyte volume than WT and Sost-/- , respectively. Quantification of metalloproteinase (MMP) activity showed that SOSTTG had ?2-fold less MMP activation than WT or Sost-/- , and this was supported by a significant reduction in MMP2/3 protein levels, suggesting that elevated levels of SOST inhibit the activity of proteolytic enzymes known to degrade articular cartilage matrix. Furthermore, intra-articular administration of recombinant Sost protein, immediately post-injury, also significantly decreased MMP activity levels relative to PBS-treated controls, and Sost activation in response to injury was TNF? and NF-?B dependent. These results provide in vivo evidence that sclerostin functions as a protective molecule immediately after joint injury to prevent cartilage degradation. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Project description:Spinal cord injury (SCI) results in rapid and extensive sublesional bone loss. Sclerostin, an osteocyte-derived glycoprotein that negatively regulates intraskeletal Wnt signaling, is elevated after SCI and may represent a mechanism underlying this excessive bone loss. However, it remains unknown whether pharmacologic sclerostin inhibition ameliorates bone loss subsequent to SCI. Our primary purposes were to determine whether a sclerostin antibody (Scl-Ab) prevents hindlimb cancellous bone loss in a rodent SCI model and to compare the effects of a Scl-Ab to that of testosterone-enanthate (TE), an agent that we have previously shown prevents SCI-induced bone loss. Fifty-five (n = 11-19/group) skeletally mature male Sprague-Dawley rats were randomized to receive: (A) SHAM surgery (T8 laminectomy), (B) moderate-severe (250 kilodyne) SCI, (C) 250 kilodyne SCI + TE (7.0 mg/wk, im), or (D) 250 kilodyne SCI + Scl-Ab (25 mg/kg, twice weekly, sc) for 3 weeks. Twenty-one days post-injury, SCI animals exhibited reduced hindlimb cancellous bone volume at the proximal tibia (via μCT and histomorphometry) and distal femur (via μCT), characterized by reduced trabecular number and thickness. SCI also reduced trabecular connectivity and platelike trabecular structures, indicating diminished structural integrity of the remaining cancellous network, and produced deficits in cortical bone (femoral diaphysis) strength. Scl-Ab and TE both prevented SCI-induced cancellous bone loss, albeit via differing mechanisms. Specifically, Scl-Ab increased osteoblast surface and bone formation, indicating direct bone anabolic effects, whereas TE reduced osteoclast surface with minimal effect on bone formation, indicating antiresorptive effects. The deleterious microarchitectural alterations in the trabecular network were also prevented in SCI + Scl-Ab and SCI + TE animals, whereas only Scl-Ab completely prevented the reduction in cortical bone strength. Our findings provide the first evidence indicating that sclerostin inhibition represents a viable treatment to prevent SCI-induced cancellous and cortical bone deficits and provides preliminary rationale for future clinical trials focused on evaluating whether Scl-Ab prevents osteoporosis in the SCI population.

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Dataset Information

Genetic deletion of Sost or pharmacological inhibition of sclerostin prevent multiple myeloma-induced bone disease without affecting tumor growth.

Publications

Genetic deletion of Sost or pharmacological inhibition of sclerostin prevent multiple myeloma-induced bone disease without affecting tumor growth.

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