Sclerostin is overexpressed by plasma cells from multiple myeloma patients

Brunetti, Giacomina; Oranger, Angela; Mori, Giorgio; Specchia, Giorgina; Rinaldi, Erminia; Curci, Paola; Zallone, Alberta; Rizzi, Rita; Grano, Maria; Colucci, Silvia

doi:10.1111/j.1749-6632.2011.06196.x

Cited by 77 publications

(62 citation statements)

References 13 publications

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“…However, the source of Sclerostin remains unclear. CD138 + cells from MM patients were reported to express Sclerostin (48); but we could not detect Sost mRNA in any patient CD138 + cells studied. In contrast, our in vitro and in vivo models demonstrate that Sost /Sclerostin expression is elevated in osteocytes.…”

Section: Discussioncontrasting

confidence: 67%

Bidirectional Notch Signaling and Osteocyte-Derived Factors in the Bone Marrow Microenvironment Promote Tumor Cell Proliferation and Bone Destruction in Multiple Myeloma

et al. 2016

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In multiple myeloma (MM) increased numbers of monoclonal plasma cells in the bone marrow induce localized osteolytic lesions that rarely heal, due to increased bone resorption and suppressed bone formation. Numerous studies reported the contributions that different cell types in the MM microenvironment make to MM growth and bone disease, but the role of matrix-embedded osteocytes in MM, which comprise >95% of bone cells and are major regulators of osteoclast and osteoblast activity, is unclear. We report that osteocytes in MM-bearing bones physically interact with MM cells in vivo, undergo caspase3-dependent apoptosis, and express higher RANKL and Sclerostin levels than osteocytes from control mice. Mechanistic studies revealed that osteocyte apoptosis is initiated by activation of Notch signaling in osteocytes through direct contact with MM cells, and is further amplified by MM cell-secreted TNFα. This Notch/TNFα induced osteocyte apoptosis increases osteocytic Rankl expression, the osteocytic Rankl/Opg ratio and the ability of osteocytes to attract osteoclast precursors to induce local bone resorption. Further, osteocytes in contact with MM cells express high levels of Sost/Sclerostin that decrease Wnt signaling in osteoblasts and inhibit osteoblast differentiation. Importantly, direct contact between osteocytes and MM cells reciprocally activates Notch signaling and increases Notch receptor expression in MM cells, in particular Notch3 and 4, and stimulates MM cell growth. These studies reveal a previously unknown role for bidirectional Notch signaling between MM cells and osteocytes that enhances MM growth and bone disease, and suggest the potential of targeting osteocyte-MM cell interactions as a novel MM treatment.

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Section: Discussioncontrasting

confidence: 67%

Bidirectional Notch Signaling and Osteocyte-Derived Factors in the Bone Marrow Microenvironment Promote Tumor Cell Proliferation and Bone Destruction in Multiple Myeloma

et al. 2016

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“…47 We can suppose that these high sclerostin levels could be derived directly from MM cells rather than from osteocytes because it has been reported that MM cells overexpress sclerostin. 48 Nevertheless, we cannot exclude that apoptotic osteocytes contribute to the increased sclerostin levels in MM patients because it has been reported that pro-apototic factors may induce sclerostin expression by osteocytes and OBs. 49,50 Overall, our data, in line with several recent evidences, 19,51 --53 support the hypothesis that osteocytic cell death stimulates OCL formation through the upregulation of pro-osteoclastogenic cytokines.…”

Section: Discussionmentioning

confidence: 91%

Increased osteocyte death in multiple myeloma patients: role in myeloma-induced osteoclast formation

et al. 2012

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The involvement of osteocytes in multiple myeloma (MM)-induced osteoclast (OCL) formation and bone lesions is still unknown. Osteocytes regulate bone remodelling at least partially, as a result of their cell death triggering OCL recruitment. In this study, we found that the number of viable osteocytes was significantly smaller in MM patients than in healthy controls, and negatively correlated with the number of OCLs. Moreover, the MM patients with bone lesions had a significantly smaller number of viable osteocytes than those without, partly because of increased apoptosis. These findings were further confirmed by ultrastructural in vitro analyses of human preosteocyte cells cocultured with MM cells, which showed that MM cells increased preosteocyte death and apoptosis. A micro-array analysis showed that MM cells affect the transcriptional profiles of preosteocytes by upregulating the production of osteoclastogenic cytokines such as interleukin (IL)-11, and increasing their pro-osteoclastogenic properties. Finally, the osteocyte expression of IL-11 was higher in the MM patients with than in those without bone lesions. Our data suggest that MM patients are characterized by a reduced number of viable osteocytes related to the presence of bone lesions, and that this is involved in MM-induced OCL formation.Leukemia ( Keywords: multiple myeloma; osteocytes; bone disease; osteoclasts INTRODUCTIONThe presence of osteolytic bone lesions or osteoporosis is the hallmark of multiple myeloma (MM), and leads to bone fragility and fractures in MM patients. The bone lesions are characterized by severely unbalanced and uncoupled bone remodelling in the area of plasma cell infiltration due to increased osteoclast (OCL) formation and activity, and osteoblast (OB) suppression. 1 --3 Local factors produced by MM cells and the bone marrow microenvironment are involved in the MM-induced increase in osteoclastogenesis, and include an imbalance in the receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) ratio that favours RANKL, 2,4 and the MM cell production of osteoclastogenic factors such as Chemokine (C --C motif) ligand 3 (CCL3)/macrophage inflammatory proteins (MIP)-1a. 5 --7 OB exhaustion is mainly due to a reduction in OB differentiation and formation, from mesenchymal stem cells and OB progenitors, that is induced by MM cells as a result of cell-to-cell contacts and the release of soluble factors. 3,8 --11 Osteocytes are differentiated cells of osteogenic lineage 12 located in the lacuno-canalicular system of the bone (see the review by Bonewald). 13 There is increasing evidence that they regulate physiological local bone remodelling, 13 --16 partly as a result of the cell death and apoptosis that triggers OCL formation and bone resorption, 15 --19 and partly by secreting sclerostin, a molecule that is specifically produced by osteocytes that inhibits bone formation. 20,21 Interestingly, an apoptosis-related reduction in osteocyte viability has recently been demonstrated in

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“…This contrasts with reports of sclerostin expression detected by reverse transcription polymerase chain reaction in plasma cells isolated from a small cohort of patients with myeloma. 55,56 The reason for this is unclear, but it likely reflects technical differences among studies. We also showed that global Dkk1 and Sost expression was decreased in bones isolated from mice bearing myeloma.…”

Section: Discussionmentioning

confidence: 99%

Inhibiting the osteocyte-specific protein sclerostin increases bone mass and fracture resistance in multiple myeloma

McDonald

Reagan

Youlten

et al. 2017

Blood

168

161

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Multiple myeloma (MM) is a plasma cell cancer that develops in the skeleton causing profound bone destruction and fractures. The bone disease is mediated by increased osteoclastic bone resorption and suppressed bone formation. Bisphosphonates used for treatment inhibit bone resorption and prevent bone loss but fail to influence bone formation and do not replace lost bone, so patients continue to fracture. Stimulating bone formation to increase bone mass and fracture resistance is a priority; however, targeting tumor-derived modulators of bone formation has had limited success. Sclerostin is an osteocyte-specific Wnt antagonist that inhibits bone formation. We hypothesized that inhibiting sclerostin would prevent development of bone disease and increase resistance to fracture in MM. Sclerostin was expressed in osteocytes from bones from naive and myeloma-bearing mice. In contrast, sclerostin was not expressed by plasma cells from 630 patients with myeloma or 54 myeloma cell lines. Mice injected with 5TGM1-eGFP, 5T2MM, or MM1.S myeloma cells demonstrated significant bone loss, which was associated with a decrease in fracture resistance in the vertebrae. Treatment with anti-sclerostin antibody increased osteoblast numbers and bone formation rate but did not inhibit bone resorption or reduce tumor burden. Treatment with anti-sclerostin antibody prevented myeloma-induced bone loss, reduced osteolytic bone lesions, and increased fracture resistance. Treatment with anti-sclerostin antibody and zoledronic acid combined increased bone mass and fracture resistance when compared with treatment with zoledronic acid alone. This study defines a therapeutic strategy superior to the current standard of care that will reduce fractures for patients with MM

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Sclerostin is overexpressed by plasma cells from multiple myeloma patients

Cited by 77 publications

References 13 publications

Bidirectional Notch Signaling and Osteocyte-Derived Factors in the Bone Marrow Microenvironment Promote Tumor Cell Proliferation and Bone Destruction in Multiple Myeloma

Bidirectional Notch Signaling and Osteocyte-Derived Factors in the Bone Marrow Microenvironment Promote Tumor Cell Proliferation and Bone Destruction in Multiple Myeloma

Increased osteocyte death in multiple myeloma patients: role in myeloma-induced osteoclast formation

Inhibiting the osteocyte-specific protein sclerostin increases bone mass and fracture resistance in multiple myeloma

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