Wen Ling

University of Arkansas at Little Rock, Little Rock, Arkansas, United States

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Publications (21)93.92 Total impact

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    ABSTRACT: Background: Human primary myeloma (MM) cells do not survive in culture; current in vitro and in vivo systems for growing these cells are limited to coculture with a specific bone marrow (BM) cell type or growth in an immunodeficient animal model. The purpose of the study is to establish an interactive healthy donor whole BM based culture system capable of maintaining prolonged survival of primary MM cells. This normal BM (NBM) coculture system is different from using autologous BM that is already affected by the disease. Methods: Whole BM from healthy donors was cultured in medium supplemented with BM serum from MM patients for 7 days, followed by 7 days of coculture with CD138-selected primary MM cells or MM cell lines. MM cells in the coculture were quantified using flow cytometry or bioluminescence of luciferase-expressing MM cells. T-cell cytokine array and proteomics were performed to identify secreted factors. Results: NBM is composed of adherent and nonadherent compartments containing typical hematopoietic and mesenchymal cells. MM cells, or a subset of MM cells, from all examined cases survived and grew in this system, regardless of the MM cells' molecular risk or subtype, and growth was comparable to coculture with individual stromal cell types. Adherent and nonadherent compartments supported MM growth, and this support required patient serum for optimal growth. Increased levels of MM growth factors IL-6 and IL-10 along with MM clinical markers B2M and LDHA were detected in supernatants from the NBM coculture than from the BM cultured alone. Levels of extracellular matrix factors (e.g., MMP1, HMCN1, COL3A1, ACAN) and immunomodulatory factors (e.g., IFI16, LILRB4, PTPN6, AZGP1) were changed in the coculture system. The NBM system protected MM cells from dexamethasone but not bortezomib, and effects of lenalidomide varied. Conclusions: The NBM system demonstrates the ability of primary MM plasma cells to interact with and to survive in coculture with healthy adult BM. This model is suitable for studying MM-microenvironment interactions, particularly at the early stage of engagement in new BM niches, and for characterizing MM cell subpopulations capable of long-term survival through secretion of extracellular matrix and immune-related factors.
    Full-text · Article · Nov 2015 · BMC Cancer
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    ABSTRACT: Objective: To explore the feasibility of establishment of NOD/SCID-mouse model with multiple myeloma by using plasma cells from myeloma patients. Methods: The femurs and tibias were removed from the New Zealand white rabbits; the muscles, periosteum and cartilage tissues were cleared. Then each bone was cut into two pieces gently along its middle. The NOD/SCID mice weighing 25-30 g (4-6 weeks) were anesthetized by intraperitoneal injection; rabbit bone was inserted into the right side of the mouse back and engraftment of the bones was allowed to take place after 4 weeks. The 5000 000 purified plasma cells which expressed CD38+/CD45- were immunofluorescence labeled and then injected slowly into the implanted rabbit bone through the distal end. The mice were observed weekly; the plasma cells growth in mice was screened by the living-imaging system and the tumor from the mice was determined by biopsy. Results: The implanted rabbit bone survived after 4 weeks. The tumor in mice was observed 2 weeks after the purified myeloma cells were injected into the rabbit bone, and it reached 100 mm3 after 8 weeks. Results: of the living-imaging system showed that the myeloma cells had uptake in the rabbit bone after 2 weeks of injection and this phenomenon was more pronounced after 8 weeks of injection (2.4×104 vs. 1.5×105, P<0.05). The tumor infiltrated with numerous plasma cells and osteoclasts increased upon the biopsy. Conclusion: Rabbit bone marrow implanted into NOD/SCID mice can effectively support local injection of plasma cells of multiple myeloma patients, and the NOD/SCID-mouse model of myeloma has been established. This model can be used to study in vivo experiments related to myeloma and clinical therapeutic approaches for this disease.
    No preview · Article · Jul 2015
  • X. Li · W. Ling · Z. Xu · Y. Wei · T. Li
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    ABSTRACT: A novel graded tapered fiber optic interface device is proposed. The interface device is a tapered graded photonic crystal fiber (PCF. about 150 mm in length. Using the finite element method, we studied the loss between different fibers with great difference in mode field diameters when they were splicing. The results showed that the coupling loss can effectively reduce after joining the tapered optical fiber between the fibers with the mode field diameter 9 μm and 10.4μm, and coupling losses are maintained at a low level at different wavelengths. Thus, the interface device can achieve the transition of the physical structure when the optical fibers splice and the conversion between the optical fibers with different mode field radius, thereby minimizing the splicing loss. ©, 2015, Editorial Office of High Power Laser and Particle Beams. All right reserved.
    No preview · Article · May 2015 · Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams

  • No preview · Article · Dec 2014 · Blood
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    ABSTRACT: Bruton's tyrosine kinase (BTK) and the chemokine receptor CXCR4 are linked in various hematologic malignancies. The aim of the study was to understand the role of BTK in myeloma cell growth and metastasis using the stably BTK knockdown luciferase-expressing INA6 myeloma line. BTK knockdown had reduced adhesion to stroma and migration of myeloma cells toward stromal cell-derived factor-1. BTK knockdown had no effect on short-term in vitro growth of myeloma cells, although clonogenicity was inhibited and myeloma cell growth was promoted in coculture with osteoclasts. In severe combined immunodeficient-rab mice with contralaterally implanted pieces of bones, BTK knockdown in myeloma cells promoted their proliferation and growth in the primary bone but suppressed metastasis to the contralateral bone. BTK knockdown myeloma cells had altered the expression of genes associated with adhesion and proliferation and increased mammalian target of rapamycin signaling. In 176 paired clinical samples, BTK and CXCR4 expression was lower in myeloma cells purified from a focal lesion than from a random site. BTK expression in random-site samples was correlated with proportions of myeloma cells expressing cell surface CXCR4. Our findings highlight intratumoral heterogeneity of myeloma cells in the bone marrow microenvironment and suggest that BTK is involved in determining proliferative, quiescent or metastatic phenotypes of myeloma cells.Blood Cancer Journal (2014) 4, e234; doi:10.1038/bcj.2014.54.
    Full-text · Article · Aug 2014 · Blood Cancer Journal
  • K. Sun · J. Liu · X. Li · W. Ling
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    ABSTRACT: Anthropogenic soil contamination has become a worldwide environmental problem in the past decades. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants in soil contaminated with crude oil, creosote, and coal tar. They are generated and dispersed into the environment by fossil fuel combustion, wood treatment processes, automobile exhaust, and waste incineration. The effect and fate of PAHs in soil is of great environmental and human health concern because of the carcinogenic, mutagenic, and teratogenic properties of PAHs. They have been frequently found in soils with high concentrations. PAHs present in soil may be absorbed by plants and translocated from roots to shoots, which is the major pathway for toxic organic substances to reach the food chain/ web. Because plants form the basis of human and animal food chains, potentially harmful organic contaminants could find their way into human and animal populations via this route. Clearly, understanding the uptake of PAHs by plant and reducing the plant PAH contamination are essential for assessment of both the PAH exposure to humans and other animal species and the risk represented by PAH-contaminated soils. Endophytic bacteria in plant tissues protect plants from external harsh environments and promote the plant growth. However, there is still little information available heretofore on the endophytic bacteria-influenced uptake and metabolism of PAHs by plants. We proposed that isolation of PAH-degrading endophytic bacteria from plant and colonization of them in the target plants are expected to improve the PAH degradation in plant, thereby reducing the risk of plant PAH contamination. In this study, two pyrene-degrading endophytic bacterial strains, named as BJ03 and BJ05, were isolated from plants grown in PAH-contaminated soils. They were individually identified as Acinetobacter sp. and Kocuria sp. based on the morphology, physiology, and 16S rDNA gene sequence analysis. The degradation characteristics of pyrene by strains BJ03 and BJ05 with different environmental conditions were investigated. It was observed that 65.0% and 53.3% of pyrene in culture solution were degraded by BJ03 and BJ05 at 30 °Cand 150 r/ min in 15 days, respectively. The two strains grew well under the condition of pH 6-9, 25-40 °C, and NaCl concentrations of 0-15 g/ L. BJ03 and BJ05 grew aerobically, and the stronger aeration resulted in their better growth and the faster degradation of pyrene in culture solution. The addition of exotic carbon (C) and nitrogen (N) sources in medium effectively promoted the bacteria growth and pyrene degradation. When sucrose and yeast extract were added as the respective C and N sources, 71.1% and 55.3% of pyrene were degraded by BJ03 and BJ05 within 4 days. BJ03 and BJ05 were observed with different cell surface hydrophobicity. The resistance tests revealed that the obtained two strains were sensitive to tetracycline and rifampicin, but were resistant to a variety of other antibiotics. This study provides new perspectives on the endophytic bacteria-influenced uptake of organic contaminants by plants. Results are valuable for the risk assessment of plant PAH contamination, and are instructive to the management of PAH-contaminated sites.
    No preview · Article · Jan 2014 · Acta Ecologica Sinica
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    ABSTRACT: Myeloma cells typically grow in bone, recruit osteoclast precursors and induce their differentiation and activity in areas adjacent to tumor foci. Bruton's tyrosine kinase (BTK), of the TEC family, is expressed in hematopoietic cells and is particularly involved in B-lymphocyte function and osteoclastogenesis. We demonstrated BTK expression in clinical myeloma plasma cells, interleukin (IL)-6- or stroma-dependent cell lines and osteoclasts. SDF-1 induced BTK activation in myeloma cells and BTK inhibition by small hairpin RNA or the small molecule inhibitor, LFM-A13, reduced their migration toward stromal cell-derived factor-1 (SDF-1). Pretreatment with LFM-A13 also reduced in vivo homing of myeloma cells to bone using bioluminescence imaging in the SCID-rab model. Enforced expression of BTK in myeloma cell line enhanced cell migration toward SDF-1 but had no effect on short-term growth. BTK expression was correlated with cell-surface CXCR4 expression in myeloma cells (n=33, r=0.81, p<0.0001), and BTK gene and protein expression was more profound in cell-surface CXCR4-expressing myeloma cells. BTK was not upregulated by IL-6 while its inhibition had no effect on IL-6 signaling in myeloma cells. Human osteoclast precursors also expressed BTK and cell-surface CXCR4 and migrated toward SDF-1. LFM-A13 suppressed migration and differentiation of osteoclast precursors as well as bone-resorbing activity of mature osteoclasts. In primary myeloma-bearing SCID-rab mice, LFM-A13 inhibited osteoclast activity, prevented myeloma-induced bone resorption and moderately suppressed myeloma growth. These data demonstrate BTK and cell-surface CXCR4 association in myeloma cells and that BTK plays a role in myeloma cell homing to bone and myeloma-induced bone disease. Am. J. Hematol., 2013. © 2013 Wiley Periodicals, Inc.
    Full-text · Article · Jun 2013 · American Journal of Hematology
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    ABSTRACT: Multiple myeloma (MM) cells typically grow in focal lesions, stimulating osteoclasts that destroy bone and support MM. Osteoclasts and MM cells are hypermetabolic. The coenzyme nicotinamide adenine dinucleotide (NAD(+)) not only is essential for cellular metabolism but also affects activity of NAD-dependent enzymes, such as PARP-1 and SIRT-1. Nicotinamide phosphoribosyltransferase (NAMPT/PBEF/visfatin, encoded by PBEF1) is a rate-limiting enzyme in NAD(+) biosynthesis from nicotinamide. Coculture of primary MM cells with osteoclasts induced PBEF1 upregulation in both cell types. PBEF1 expression was higher in experimental myelomatous bones than in nonmyelomatous bone and in MM patients' plasma cells than in healthy donors' counterparts. APO866 is a specific PBEF1 inhibitor known to deplete cellular NAD(+). APO866 at low nanomolar concentrations inhibited growth of primary MM cells or MM cell lines cultured alone or cocultured with osteoclasts and induced apoptosis in these cells. PBEF1 activity and NAD(+) content were reduced in MM cells by APO866, resulting in lower activity of PARP-1 and SIRT-1. The inhibitory effect of APO866 on MM cell growth was abrogated by supplementation of extracellular NAD(+) or NAM. APO866 inhibited NF-kB activity in osteoclast precursors and suppressed osteoclast formation and activity. PBEF1 knockdown similarly inhibited MM cell growth and osteoclast formation. In the SCID-rab model, APO866 inhibited growth of primary MM and H929 cells and prevented bone disease. These findings indicate that MM cells and osteoclasts are highly sensitive to NAD(+) depletion and that PBEF1 inhibition represents a novel approach to target cellular metabolism and inhibit PARP-1 and bone disease in MM.
    Full-text · Article · Feb 2013 · Experimental hematology
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    ABSTRACT: Multiple myeloma (MM) cells typically grow in focal lesions, stimulating osteoclasts that destroy bone and support MM. Osteoclasts and MM cells are hypermetabolic. The coenzyme nicotinamide adenine dinucleotide (NAD(+)) not only is essential for cellular metabolism but also affects activity of NAD-dependent enzymes, such as PARP-1 and SIRT-1. Nicotinamide phosphoribosyltransferase (NAMPT/PBEF/visfatin, encoded by PBEF1) is a rate-limiting enzyme in NAD(+) biosynthesis from nicotinamide. Coculture of primary MM cells with osteoclasts induced PBEF1 upregulation in both cell types. PBEF1 expression was higher in experimental myelomatous bones than in nonmyelomatous bone and in MM patients' plasma cells than in healthy donors' counterparts. APO866 is a specific PBEF1 inhibitor known to deplete cellular NAD(+). APO866 at low nanomolar concentrations inhibited growth of primary MM cells or MM cell lines cultured alone or cocultured with osteoclasts and induced apoptosis in these cells. PBEF1 activity and NAD(+) content were reduced in MM cells by APO866, resulting in lower activity of PARP-1 and SIRT-1. The inhibitory effect of APO866 on MM cell growth was abrogated by supplementation of extracellular NAD(+) or NAM. APO866 inhibited NF-kB activity in osteoclast precursors and suppressed osteoclast formation and activity. PBEF1 knockdown similarly inhibited MM cell growth and osteoclast formation. In the SCID-rab model, APO866 inhibited growth of primary MM and H929 cells and prevented bone disease. These findings indicate that MM cells and osteoclasts are highly sensitive to NAD(+) depletion and that PBEF1 inhibition represents a novel approach to target cellular metabolism and inhibit PARP-1 and bone disease in MM.
    No preview · Article · Feb 2013 · Experimental Hematology
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    Xin Li · Wen Ling · Sharmin Khan · Shmuel Yaccoby
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    ABSTRACT: The cytotherapeutic potential of mesenchymal stem cells (MSCs) has been evaluated in various disorders including those involving inflammation, autoimmunity, bone regeneration, and cancer. Multiple myeloma (MM) is a systemic malignancy associated with induction of osteolytic lesions that often are not repaired even after prolonged remission. The aims of this study were to evaluate the effects of intrabone and systemic injections of MSCs on MM bone disease, tumor growth, and tumor regrowth in the severe combined immunodeficiency (SCID)-rab model and to shed light on the exact localization of systemically injected MSCs. Intrabone injection of MSCs, but not hematopoietic stem cells, into myelomatous bones prevented MM-induced bone disease, promoted bone formation, and inhibited MM growth. After remission was induced with melphalan treatment, intrabone-injected MSCs promoted bone formation and delayed myeloma cell regrowth in bone. Most intrabone or systemically injected MSCs were undetected 2 to 4 weeks after injection. The bone-building effects of MSCs were mediated through activation of endogenous osteoblasts and suppression of osteoclast activity. Although a single intravenous injection of MSCs had no effect on MM, sequential weekly intravenous injections of MSCs prevented MM-induced bone disease but had no effect on tumor burden. MSCs expressed high levels of anti-inflammatory (eg, HMOX1) and bone-remodeling (eg, Decorin, CYR61) mediators. In vitro, MSCs promoted osteoblast maturation and suppressed osteoclast formation, and these effects were partially prevented by blocking decorin. A subset of intravenously or intracardially injected MSCs trafficked to myelomatous bone in SCID-rab mice. Although the majority of intravenously injected MSCs were trapped in lungs, intracardially injected MSCs were mainly localized in draining mesenteric lymph nodes. This study shows that exogenous MSCs act as bystander cells to inhibit MM-induced bone disease and tumor growth and that systemically injected MSCs are attracted to bone by myeloma cells or conditions induced by MM and inhibit bone disease.
    Full-text · Article · Aug 2012 · Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research
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    ABSTRACT: Iron overload is a significant clinical feature in multiple myeloma (MM) and has been implicated in osteoporosis. MM patients also frequently suffer from anemia presumably due to elevated hepcidin secretion and dysfunctional erythropoiesis. The aims of the study were to shed light on molecular mechanisms associated with iron overload in MM cells and study the effect of the novel iron chelator, Dp44mT, on MM cell growth, osteoclastogenesis and MM bone disease in vitro and in vivo. In our clinical global gene expression profiling (GEP) data the main iron transporter gene TFRC (transferrin receptor) was >3 folds higher (p<0.0001) in newly diagnosed MM cells (n=556) than normal plasma cells (n=25) while the iron exporter ferroportin was downregulated in MM cells by >4 folds (p<0.0001). Deregulated TFRC and ferroportin expression were more profound in the molecularly classified proliferation (PR) subtype. Osteoclasts which are known to have abundant mitochondria due to high energy consumption express excessive TFRC (>5 folds higher than highly proliferating MM cells). In primary MM cell-osteoclast cocultures (n=8) TFRC expression was upregulated in cocultured MM cells than baseline MM cells (p<0.03) while ferroportin was lower in cocultured osteoclasts than control osteoclasts (p<0.04). Our GEP, qRT-PCR and immunohistochemistry analyses revealed expression of hepcidin by osteoclasts but not MM cells. Hepcidin was not detected in conditioned media from osteoclasts cultured alone or cocultured with MM cells using ELISA, suggesting an autocrine role of hepcidin in maintaining excess iron in osteoclasts. In vitro, Dp44mT dose dependently inhibited growth of MM cell lines (n=3) at low nanomolar levels (IC50 at 3±0.8 nM, p<0.03, 48 hrs). In contrast, known chelators such as Deferoxamine and Deferasirox inhibited myeloma cell growth at 10–50 micromoles range. At 1nM Dp44mT also suppressed formation of multinucleated osteoclasts by 87% (p<0.001) and bone resorbing activity of mature osteoclasts on dentine slices by 94% (p<0.03). Dp44mT induced upregulation of BMP2 expression in osteoblast precursors and promoted osteoblast differentiation. In vivo, SCID-rab mice engrafted with luciferase-expressing U266 MM line (6 mice/group) or the Hg MM line (maintained through in vivo passaging, 10 mice/group) were subcutaneously treated with vehicle or Dp44mT (1 mg/kg/day) for 2–3 weeks. Using live-animal imaging, Dp44mT reduced growth of U266 cells by 3 folds from pretreatment levels (p<0.01) while in control group tumor burden was increased by 52 folds from pretreatment levels (p<0.002). Dp44mT also inhibited growth of Hg MM cells determined by measurement of circulating human immunoglobulins in mice sera (p<0.01). Osteoclasts numbers were lower by 36% (p<0.003) while osteoblasts numbers were higher by 59% (p<0.017) in myelomatous bones from hosts treated with Dp44mT than control vehicle. Our data suggest that interaction of myeloma cells with osteoclasts alters expression of distinct iron metabolism associated factors which elicit iron overload in both cell types, resulting in increased myeloma cell proliferation and osteoclast activity. This study also suggests that Dp44mT is an effective iron chelator with marked anti-MM activity.
    No preview · Conference Paper · Dec 2011
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    ABSTRACT: Human placenta has emerged as a valuable source of transplantable cells of mesenchymal and hematopoietic origin for multiple cytotherapeutic purposes, including enhanced engraftment of hematopoietic stem cells, modulation of inflammation, bone repair, and cancer. Placenta-derived adherent cells (PDACs) are mesenchymal-like stem cells isolated from postpartum human placenta. Multiple myeloma is closely associated with induction of bone disease and large lytic lesions, which are often not repaired and are usually the sites of relapses. We evaluated the antimyeloma therapeutic potential, in vivo survival, and trafficking of PDACs in the severe combined immunodeficiency (SCID)-rab model of medullary myeloma-associated bone loss. Intrabone injection of PDACs into nonmyelomatous and myelomatous implanted bone in SCID-rab mice promoted bone formation by stimulating endogenous osteoblastogenesis, and most PDACs disappeared from bone within 4 weeks. PDACs inhibitory effects on myeloma bone disease and tumor growth were dose-dependent and comparable with those of fetal human mesenchymal stem cells (MSCs). Intrabone, but not subcutaneous, engraftment of PDACs inhibited bone disease and tumor growth in SCID-rab mice. Intratumor injection of PDACs had no effect on subcutaneous growth of myeloma cells. A small number of intravenously injected PDACs trafficked into myelomatous bone. Myeloma cell growth rate in vitro was lower in coculture with PDACs than with MSCs from human fetal bone or myeloma patients. PDACs also promoted apoptosis in osteoclast precursors and inhibited their differentiation. This study suggests that altering the bone marrow microenvironment with PDAC cytotherapy attenuates growth of myeloma and that PDAC cytotherapy is a promising therapeutic approach for myeloma osteolysis.
    Full-text · Article · Feb 2011 · Stem Cells
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    Dataset: Table S1
    Angela Pennisi · Wen Ling · Xin Li · Sharmin Khan · Yuping Wang · Bart Barlogie · John D. Shaughnessy · Shmuel Yaccoby
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    ABSTRACT: Genes whose expression was significantly upregulated or downregulated by PTH treatment in whole human bone from SCID-hu mice. SCID-hu mice engrafted with Hg myeloma cells were treated with saline or PTH for 4 weeks. Mice were sacrificed 2 hours after the last injection. RNA extracted from the whole myelomatous human bone (five bones/group) was subjected to global gene expression profiling. Positive (POS) or negative (NEG) expression of those genes in Hg myeloma cells is indicated to assess cellular source of these genes (e.g., microenvironmental and/or tumor cells). (XLS)
    Preview · Dataset · Dec 2010
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    ABSTRACT: Induction of osteolytic bone lesions in multiple myeloma is caused by an uncoupling of osteoclastic bone resorption and osteoblastic bone formation. Current management of myeloma bone disease is limited to the use of antiresorptive agents such as bisphosphonates. We tested the effects of daily administered parathyroid hormone (PTH) on bone disease and myeloma growth, and we investigated molecular mechanisms by analyzing gene expression profiles of unique myeloma cell lines and primary myeloma cells engrafted in SCID-rab and SCID-hu mouse models. PTH resulted in increased bone mineral density of myelomatous bones and reduced tumor burden, which reflected the dependence of primary myeloma cells on the bone marrow microenvironment. Treatment with PTH also increased bone mineral density of uninvolved murine bones in myelomatous hosts and bone mineral density of implanted human bones in nonmyelomatous hosts. In myelomatous bone, PTH markedly increased the number of osteoblasts and bone-formation parameters, and the number of osteoclasts was unaffected or moderately reduced. Pretreatment with PTH before injecting myeloma cells increased bone mineral density of the implanted bone and delayed tumor progression. Human global gene expression profiling of myelomatous bones from SCID-hu mice treated with PTH or saline revealed activation of multiple distinct pathways involved in bone formation and coupling; involvement of Wnt signaling was prominent. Treatment with PTH also downregulated markers typically expressed by osteoclasts and myeloma cells, and altered expression of genes that control oxidative stress and inflammation. PTH receptors were not expressed by myeloma cells, and PTH had no effect on myeloma cell growth in vitro. We conclude that PTH-induced bone formation in myelomatous bones is mediated by activation of multiple signaling pathways involved in osteoblastogenesis and attenuated bone resorption and myeloma growth; mechanisms involve increased osteoblast production of anti-myeloma factors and minimized myeloma induction of inflammatory conditions.
    Preview · Article · Dec 2010 · PLoS ONE
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    ABSTRACT: Myeloma bone disease is caused by uncoupling of osteoclastic bone resorption and osteoblastic bone formation. Bidirectional signaling between the cell-surface ligand ephrinB2 and its receptor, EphB4, is involved in the coupling of osteoblastogenesis and osteoclastogenesis and in angiogenesis. EphrinB2 and EphB4 expression in mesenchymal stem cells (MSCs) from myeloma patients and in bone cells in myelomatous bones was lower than in healthy counterparts. Wnt3a induced up-regulation of EphB4 in patient MSCs. Myeloma cells reduced expression of these genes in MSCs, whereas in vivo myeloma cell-conditioned media reduced EphB4 expression in bone. In osteoclast precursors, EphB4-Fc induced ephrinB2 phosphorylation with subsequent inhibition of NFATc1 and differentiation. In MSCs, EphB4-Fc did not induce ephrinB2 phosphorylation, whereas ephrinB2-Fc induced EphB4 phosphorylation and osteogenic differentiation. EphB4-Fc treatment of myelomatous SCID-hu mice inhibited myeloma growth, osteoclastosis, and angiogenesis and stimulated osteoblastogenesis and bone formation, whereas ephrinB2-Fc stimulated angiogenesis, osteoblastogenesis, and bone formation but had no effect on osteoclastogenesis and myeloma growth. These chimeric proteins had similar effects on normal bone. Myeloma cells expressed low to undetectable ephrinB2 and EphB4 and did not respond to the chimeric proteins. The ephrinB2/EphB4 axis is dysregulated in MM, and its activation by EphB4-Fc inhibits myeloma growth and bone disease.
    Preview · Article · Aug 2009 · Blood
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    ABSTRACT: Fenretinide (4HPR), a nontoxic analog of ATRA, has been investigated in various malignancies but not in multiple myeloma (MM), a plasma cell malignancy associated with induction of osteolytic bone disease. Here we show that 4HPR induces apoptosis through increased level of ROS and activation of caspase-8, 9 and 3, and inhibits growth of several MM cell lines in a dose-dependent manner. Serum or co-culture with the supportive osteoclasts partially protects MM cells from 4HPR-induced growth inhibition. Sphingosine-1 phosphate (S1P) significantly protects MM cells from 4HPR-induced apoptosis suggesting that as in other malignancies, this drug up-regulates ceramide in MM cells. 4HPR has no toxic effects on non-malignant cells such as blood mononucleated cells, mesenchymal stem cells and osteoblasts, but markedly reduces viability of endothelial cells and mature osteoclasts and inhibits differentiation of osteoclasts and MM-induced tube formation. 4HPR is a potential anti-MM agent, affecting MM cells and MM-induced bone disease and angiogenesis.
    Preview · Article · Jun 2009 · Cancer letters
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    ABSTRACT: Dipeptidyl peptidase (DPP) IV activity and/or structure homologues (DASH) are serine proteases implicated in tumourigenesis. We previously found that a DASH protease, fibroblast activation protein (FAP), was involved in osteoclast-induced myeloma growth. Here we further demonstrated expression of various adhesion molecules in osteoclasts cultured alone or cocultured with myeloma cells, and tested the effects of DASH inhibitor, PT-100, on myeloma cell growth, bone disease, osteoclast differentiation and activity, and expression of adhesion molecules in osteoclasts. PT-100 had no direct effects on viability of myeloma cells or mature osteoclasts, but significantly reduced survival of myeloma cells cocultured with osteoclasts. Real-time PCR array for 85 adhesion molecules revealed upregulation of 17 genes in osteoclasts after coculture with myeloma cells. Treatment of myeloma/osteoclast cocultures with PT-100 significantly downregulated 18 of 85 tested genes in osteoclasts, some of which are known to play roles in tumourigenesis and osteoclastogenesis. PT-100 also inhibited osteoclast differentiation and subsequent pit formation. Resorption activity of mature osteoclasts and differentiation of osteoblasts were not affected by PT-100. In primary myelomatous severe combined immunodeficient (SCID)-hu mice PT-100 reduced osteoclast activity, bone resorption and tumour burden. These data demonstrated that DASH proteases are involved in myeloma bone disease and tumour growth.
    Full-text · Article · May 2009 · British Journal of Haematology
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    ABSTRACT: Multiple myeloma (MM), a hematologic malignancy of terminally differentiated plasma cells is closely associated with induction of osteolytic bone disease, induced by stimulation of osteoclastogenesis and suppression of osteoblastogenesis. The ubiquitin-proteasome pathway regulates differentiation of bone cells and MM cell growth. The proteasome inhibitor, bortezomib, is a clinical potent antimyeloma agent. The main goal of this study was to investigate the effect of bortezomib on myeloma-induced bone resorption and tumor growth in SCID-rab mice engrafted with MM cells from 16 patients. Antimyeloma response of bortezomib, which was evident in >50% of 16 experiments and resembled clinical response, was associated with significant increased bone mineral density (BMD) and osteoblast numbers, and reduced osteoclast numbers in myelomatous bones. This bone anabolic effect, which was also visualized on X-ray radiographs and confirmed by static and dynamic histomorphometric analyses, was unique to bortezomib and was not observed in hosts responding to melphalan, a chemotherapeutic drug widely used to treat MM. Bortezomib also increased BMD and osteoblasts number and reduced osteoclasts number in nonmyelomatous implanted bones. In vitro bortezomib directly suppressed human osteoclast formation and promoted maturation of osteoblasts. We conclude that bortezomib promotes bone formation in myelomatous and nonmyelomatous bones by simultaneously inhibiting osteoclastogenesis and stimulating osteoblastogenesis. As clinical and experimental studies indicate that bone disease is both a consequence and necessity of MM progression our results suggest and that bortezomib's effects on bone remodeling contribute to the antimyeloma efficacy of this drug.
    Preview · Article · Jan 2009 · American Journal of Hematology
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    ABSTRACT: Dickkopf-1 (DKK1), a soluble inhibitor of Wnt signaling secreted by multiple myeloma (MM) cells contributes to osteolytic bone disease by inhibiting the differentiation of osteoblasts. In this study, we tested the effect of anti-DKK1 therapy on bone metabolism and tumor growth in a SCID-rab system. SCID-rab mice were engrafted with primary MM cells expressing varying levels of DKK1 from 11 patients and treated with control and DKK1-neutralizing antibodies for 4 to 6 weeks. Whereas bone mineral density (BMD) of the implanted myelomatous bone in control mice was reduced during the experimental period, the BMD in mice treated with anti-DKK1 increased from pretreatment levels (P < .001). Histologic examination revealed that myelomatous bones of anti-DKK1-treated mice had increased numbers of osteocalcin-expressing osteoblasts and reduced number of multinucleated TRAP-expressing osteoclasts. The bone anabolic effect of anti-DKK1 was associated with reduced MM burden (P < .04). Anti-DKK1 also significantly increased BMD of the implanted bone and murine femur in nonmyelomatous SCID-rab mice, suggesting that DKK1 is physiologically an important regulator of bone remodeling in adults. We conclude that DKK1 is a key player in MM bone disease and that blocking DKK1 activity in myelomatous bones reduces osteolytic bone resorption, increases bone formation, and helps control MM growth.
    Preview · Article · Apr 2007 · Blood
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    ABSTRACT: Multiple myeloma (MM) growth in the bone marrow is associated with increased osteoclast activity and a reduced number of osteoblasts. Experimental studies suggest that bone disease drives the progression of MM. Whereas those studies focused on the critical role of myeloma-induced osteoclastogenesis in disease progression, little is known about the impact of osteoblasts and increased bone formation on MM. We investigated the effect of isolated osteoblasts and osteoclasts on survival and proliferation of primary MM plasma cells (PC) in co-cultures and triple-cultures, and tested the effect of mesenchymal stem cells (MSC) on bone mineral density and MM growth in myelomatous human bones of SCID-hu mice. Whereas osteoclasts promoted survival and proliferation of MM PC, osteoblasts supported or inhibited MM PC, depending on the source of the MM cells. In triple-cultures osteoblasts attenuated the effect of osteoclasts on MM PC in 18 of 24 experiments. The anti-MM response to osteoblasts correlated with advanced clinical stage. Injection of MSC into myelomatous bones resulted in marked inhibition of tumor growth in three of nine experiments and stabilization of disease in two additional experiments. The anti-MM response of MSC was associated with increased human bone mineral density. Immunohistochemical analysis indicated that the MSC were well engrafted and, in responding mice, differentiated into osteogenic cells. MM PC from the majority of patients are susceptible to growth inhibition by osteoblasts; however, growth of MM PC from certain patients is accelerated by osteoblasts. In vivo, increased bone formation is associated with reduced myeloma burden.
    Full-text · Article · Mar 2006 · Haematologica