scholarly journals Increased circulating LDL cholesterol increases myeloma tumour burden in vivo

2021 ◽  
Vol 2 (4) ◽  
Author(s):  
Beatriz Gamez
Keyword(s):  
Bone Disease ◽  
Dietary Intervention ◽  
Dietary Cholesterol ◽  
Cholesterol Diet ◽  
Tumour Burden ◽  
Benign Condition ◽  
Myeloma Cells ◽  
Osteolytic Bone Disease

Gámez B., Morris EV., Olechnowicz S., Sowman, A., Turner, C. and Edwards CM.   Multiple myeloma (MM) is a fatal malignancy characterized by an expansion of malignant plasma cells in the bone marrow (BM) and associated with osteolytic bone disease. MM is preceded by the benign condition, monoclonal gammopathy of undetermined significance (MGUS). Understanding MGUS progression and development of MM bone disease is key for patient management. We and others have previously demonstrated that diet-induced obesity promotes myeloma progression, but the mechanisms underlying this remain unknown. The aim of the current study was to determine the effect of dietary cholesterol on MM development. A 2% cholesterol diet was used to increase circulating LDL in mice. Mice were randomly distributed to either a) cholesterol diet 4 weeks prior to 5TGM1 MM inoculation (pretreatment) or b) cholesterol diet 4 weeks prior to MM inoculation and continued for the entire experiment (continuous). Mice on the continuous cholesterol diet had increased tumour burden, associated with an increase in lipid droplet content of MM cells. No differences in tumour burden were seen in those mice where cholesterol diet was halted at time of MM inoculation. In vitro, myeloma cells cultured with delipidated FBS had a 50% reduction in viability after 72 hours. Rich cholesterol content lipoproteins (LDL) but not VLDL could restore MM cell viability, suggesting that cholesterol is responsible for this lipid-depletion effect. Taken together, our results show that high cholesterol promotes myeloma and results in a higher lipid content in myeloma cells, ultimately increasing BM tumour burden. Pretreatment with a cholesterol diet did not alter disease progression suggesting a direct pro-tumourigenic effect of cholesterol. These results demonstrate both the detrimental effect of cholesterol on myeloma progression and the potential for dietary intervention approaches.

scholarly journals Increased circulating LDL cholesterol increases myeloma tumour burden in vivo

2021 ◽  
Vol 2 (4) ◽  
Author(s):  
Beatriz Gamez
Keyword(s):  
Bone Disease ◽  
Dietary Intervention ◽  
Dietary Cholesterol ◽  
Cholesterol Diet ◽  
Tumour Burden ◽  
Benign Condition ◽  
Myeloma Cells ◽  
Osteolytic Bone Disease

Gámez B., Morris EV., Olechnowicz S., Sowman, A., Turner, C. and Edwards CM. Multiple myeloma (MM) is a fatal malignancy characterized by an expansion of malignantplasma cells in the bone marrow (BM) and associated with osteolytic bone disease. MM ispreceded by the benign condition, monoclonal gammopathy of undetermined significance(MGUS). Understanding MGUS progression and development of MM bone disease is key forpatient management. We and others have previously demonstrated that diet-induced obesitypromotes myeloma progression, but the mechanisms underlying this remain unknown. The aimof the current study was to determine the effect of dietary cholesterol on MM development. A2% cholesterol diet was used to increase circulating LDL in mice. Mice were randomlydistributed to either a) cholesterol diet 4 weeks prior to 5TGM1 MM inoculation (pretreatment)or b) cholesterol diet 4 weeks prior to MM inoculation and continued for the entire experiment(continuous). Mice on the continuous cholesterol diet had increased tumour burden, associatedwith an increase in lipid droplet content of MM cells. No differences in tumour burden wereseen in those mice where cholesterol diet was halted at time of MM inoculation. In vitro,myeloma cells cultured with delipidated FBS had a 50% reduction in viability after 72 hours. Richcholesterol content lipoproteins (LDL) but not VLDL could restore MM cell viability, suggestingthat cholesterol is responsible for this lipid-depletion effect. Taken together, our results showthat high cholesterol promotes myeloma and results in a higher lipid content in myeloma cells,ultimately increasing BM tumour burden. Pretreatment with a cholesterol diet did not alterdisease progression suggesting a direct pro-tumourigenic effect of cholesterol. These resultsdemonstrate both the detrimental effect of cholesterol on myeloma progression and thepotential for dietary intervention approaches.  

Targeting Wnt Signaling in Myeloma In Vivo; Differential Effects on Tumor Burden and Myeloma Bone Disease.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 812-812
Author(s):  
Claire M. Edwards ◽  
James R. Edwards ◽  
Seint T. Lwin ◽  
Gregory R. Mundy
Keyword(s):  
Bone Marrow ◽  
Wnt Signaling ◽  
Bone Disease ◽  
Tumor Burden ◽  
Bone Microenvironment ◽  
Myeloma Cells ◽  
Myeloma Bone Disease ◽  
Osteolytic Bone Disease

Abstract Multiple myeloma is characterized by uncontrolled proliferation of myeloma cells within the bone marrow and the development of a severe osteolytic bone disease. In addition to a well characterized increase in osteoclastic bone resorption, myeloma bone disease is associated with a reduction in bone formation. Osteoblast differentiation and bone formation are regulated in vivo by canonical Wnt signaling and activation of β-catenin. Therefore increasing Wnt signaling in the bone microenvironment in multiple myeloma may prevent the development of myeloma bone disease. In support of this, we have previously demonstrated that activation of Wnt signaling with lithium chloride (LiCl) in the 5TGM1 murine model of myeloma reduces tumor burden and osteolytic bone disease. However, we also found that LiCl treatment increased subcutaneous (s.c.) tumor growth. This suggests that the reduction in tumor burden within the bone microenvironment may be an indirect effect mediated through the effects of LiCl to prevent myeloma bone disease. The aim of the current study was to determine the effect of specific molecular blockade of Wnt signaling in myeloma cells in vivo. 5TGM1-GFP myeloma cells were transfected by electroporation with either myc-tagged dominant negative TCF4 (DNTCF4) or pcDNA. Following stable selection by culture in G418, expression of DNTCF4 was confirmed by western blot for myc. No difference was found in the growth rates of 5TGM1-pcDNA or 5TGM1-DNTCF4 in vitro. Treatment with LiCl or Wnt3A had no significant effect on cell viability in vitro, but significantly increased β-catenin activity, as measured by TOPFLASH activity in 5TGM1-pcDNA cells. This increase was not observed in 5TGM1-DNTCF4, confirming that expression of DNTCF4 blocked Wnt signaling induced by LiCl in 5TGM1 myeloma cells. C57Bl/KaLwRij mice were inoculated with 5TGM1-pcDNA or 5TGM1-DNTCF4 cells by either intravenous (i.v.) or s.c. injection. Mice were treated from time of tumor cell inoculation with 200mg/kg/day LiCl or vehicle control (d.H20) by oral gavage for 28 days. I.v. inoculation of myeloma cells resulted in a significant increase in serum IgG2bκ concentrations and the proportion of GFP-positive cells in the bone marrow. A significant reduction in trabecular bone volume was also observed. MicroCT analysis of the tibia demonstrated that LiCl significantly increased trabecular bone volume in both 5TGM1-pcDNA and 5TGM1-DNTCF4 myeloma-bearing mice. LiCl significantly decreased serum IgG2bκ concentrations in both 5TGM1-pcDNA and 5TGM1-DNTCF4 myeloma-bearing mice, with a greater effect in 5TGM1-DNTCF4 myeloma-bearing mice. FACS analysis of GFP-positive cells demonstrated that LiCl significantly reduced tumor burden in the bone marrow in both 5TGM1-pcDNA and 5TGM1-DNTCF4 myeloma-bearing mice. However, following s.c inoculation, LiCl significantly increased s.c. tumor volume of 5TGM1-pcDNA tumors, but had no effect on 5TGM1-DNTCF4 s.c. tumor volume. Taken together these results demonstrate that the effect of increasing Wnt signaling in myeloma is dependent upon the microenvironment. By specific inhibition of β-catenin activity in myeloma cells combined with systemic stimulation of the Wnt signaling pathway, our results suggest that increasing Wnt signaling in myeloma in vivo has dual effects; firstly to enhance myeloma growth directly, and secondly to enhance osteoblast differentiation and thus indirectly reduce tumor burden in bone, highlighting the importance of the bone marrow microenvironment in regulating myeloma growth and survival.

Inhibition of p38α MAPK Reduces Tumor Burden, Prevents the Development of Myeloma Bone Disease, and Increases Survival in the 5T2 and 5T33 Murine Models of Myeloma.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3436-3436 ◽  
Author(s):  
Karin Vanderkerken ◽  
Satya Medicherla ◽  
Les Coulton ◽  
Benjamin Van Camp ◽  
Andy Protter ◽  
...  
Keyword(s):  
Bone Disease ◽  
Critical Role ◽  
Disease Free Survival ◽  
Myeloma Cell ◽  
Bone Lesions ◽  
Myeloma Cells ◽  
Growth And Survival ◽  
Myeloma Bone Disease ◽  
Osteolytic Bone Disease

Abstract The bone microenvironment plays a critical role in supporting the growth and survival of myeloma cells and the development of osteolytic bone disease. Signalling through p38 α MAPK mediates synthesis of myeloma cell survival factors by stromal cells; whereas, inhibiting p38 α MAPK reduces myeloma cell proliferation and inhibits osteoclast formation in vitro. However, it is unclear whether p38 α MAPK inhibition will prevent the growth and survival of myeloma cells and the bone disease in vivo. The aim of this study was to determine whether SCIO-469, a selective p38 α MAPK inhibitor, would inhibit myeloma growth and prevent the development of bone disease in the 5TMM syngeneic models of myeloma. Treatment of 5TMM cells, in vitro, with SCIO-469 resulted in a clear inhibition of p38 phosphorylation, as assessed by Western blotting and an inhibition up to 35% of stromal cell induced 5T33MM proliferation. Injection of 5T2MM murine myeloma cells into C57Bl/KaLwRij mice resulted in the growth of myeloma in bone and the development of bone disease characterized by increased osteoclast surface (p<0.05), a reduction in cancellous bone (p<0.01) and the presence of osteolytic bone lesions on x-ray (p<0.01). Treatment of 5T2MM-bearing mice with SCIO-469 (150mg/kg in the diet, therapeutical treatment from paraprotein detection) resulted in a 42% decrease in serum paraprotein and prevented development of osteolytic lesions (p<0.01). Injection of 5T33MM cells into C57Bl/KaLwRij mice also resulted in the development of myeloma but not associated bone disease. Treatment of 5T33MM-bearing mice from the time of tumor cell injection with SCIO-469 resulted in a decrease in serum paraprotein (8.8+/−1.4g/dl to 0.04+/− 0.03g/dl, p<0.001) and a reduction in the proportion of tumor cells in the bone marrow (67 +/− 8.1% to 1.09 +/− 0.58%, p<0.001). Kaplan-Meier analysis demonstrated an increase in disease-free survival (veh=27.5 days vs 96 days, p<0.001) after treatment of the mice with SCIO-469. These data demonstrate that targeting p38 α MAPK with SCIO-469 is associated with an anti-myeloma effect, which indirectly prevents the development of myeloma bone disease.

Targeting CCR1 for the Treatment of Osteolytic Bone Disease in Multiple Myeloma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2503-2503
Author(s):  
Sonia Vallet ◽  
Noopur Raje ◽  
MariaTeresa Fulciniti ◽  
Kenji Ishitsuka ◽  
Teru Hideshima ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Clinical Trials ◽  
Bone Disease ◽  
Cell Number ◽  
In Vivo Studies ◽  
Protective Effects ◽  
Osteolytic Bone Disease

Abstract Osteolytic bone disease (OBD) is a frequent complication of multiple myeloma (MM), affecting 70 to 80% of the patients. OBD is characterized by imbalanced bone remodeling, due to decreased osteoblast (OB) number and increased osteoclast (OC) formation and activity. MM cells secrete osteoclastogenic factors, such as receptor activator of nuclear factor kappa B ligand (RANKL) and CCL3. In turn, OC support MM cell proliferation and survival, thus promoting a positive feedback that exacerbates bone resorption. Chemokines modulate osteoclastogenesis and promote MM cell proliferation, in particular CCL3 and its receptor CCR1 play an important role in mediating OBD in MM. MLN3897 (Millennium Pharmaceuticals, Cambridge) is a novel small molecule specific antagonist of human CCR1 (IC50 0.8 nM). It has a favorable toxicity profile in healthy volunteers and is currently undergoing phase II clinical trials in rheumatoid arthritis and multiple sclerosis. Here we evaluate the effects of MLN3897 on OC function and activity, as well as OC-MM cell interactions. Our in vitro data demonstrates a dual mechanism of action for MLN3897: it inhibits osteoclastogenesis and also overcomes the protective effects conferred by OC on MM cells. Our data further shows inhibition of OC formation and function by 40 and 70%, respectively, following MLN3897 treatment. This is mediated via inhibition of the fusion process and is accompanied by downregulation of pERK and c-fos signaling. To analyze its effect on MM cells, we verified CCR1 and CCR5 expression levels on MM1.S (15% and 3.6%) and OPM1 (3.8 and 0.7%). Our data show that OC secrete high levels of CCL3 which triggers MM cell migration; and that MLN3897 abrogates these effects by inhibiting the PI3K/Akt pathway. Moreover, MLN3897 overcomes the proliferative advantage conferred by OC on MM cells, as demonstrated in INA6, MM1.S and MM patient derived primary cells. OC induced MM cell proliferation is mediated by adhesion and cytokine secretion, and MLN3897 abrogates both MM cell-to-OC adhesion and interleukin-6 (IL6) secretion by OC in a co-culture system, thereby resulting in decreased MM cell survival and proliferation. To confirm these in vitro results, in vivo studies in a SCID-hu mouse model are underway. Implanted SCID-Hu INA-6 bearing mice are treated with twice daily oral MLN3897 for 3 weeks. The evaluation of osteolytic lesions and OC, OB and endothelial cell number; and tumor burden will be presented. Our in vitro results therefore show novel biologic sequelae of CCL3 and its inhibition on both osteoclastogenesis and MM cell growth. Our in vivo experiments will further validate the role of CCR1 in a human BM microenvironment-MM model, providing the framework for clinical trials of MLN3897 for the treatment of OBD in MM.

scholarly journals Syndecan-1 Is a Multifunctional Regulator of Myeloma Pathobiology: Control of Tumor Cell Survival, Growth, and Bone Cell Differentiation

Blood ◽  
1998 ◽  
Vol 91 (8) ◽  
pp. 2679-2688 ◽  
Author(s):  
Madhav V. Dhodapkar ◽  
Etsuko Abe ◽  
Allison Theus ◽  
Marie Lacy ◽  
J. Kevin Langford ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Heparan Sulfate ◽  
Bone Disease ◽  
Bone Cells ◽  
Bone Marrow Cells ◽  
Myeloma Cells ◽  
Bone Cell Differentiation ◽  
Dose Dependent

Multiple myeloma is characterized by an accumulation of malignant plasma cells in the bone marrow coupled with an altered balance of osteoclasts and osteoblasts, leading to lytic bone disease. Although some of the cytokines driving this process have been characterized, little is known about the negative regulators. We show that syndecan-1 (CD 138), a heparan sulfate proteoglycan, expressed on and actively shed from the surface of most myeloma cells, induces apoptosis and inhibits the growth of myeloma tumor cells and also mediates decreased osteoclast and increased osteoblast differentiation. The addition of intact purified syndecan-1 ectodomain (1 to 6 nmol/L) to myeloma cell lines in culture leads to induction of apoptosis and dose-dependent growth inhibition, with concurrent downregulation of cyclin D1. The addition of purified syndecan-1 in picomolar concentrations to bone marrow cells in culture leads to a dose-dependent decrease in osteoclastogenesis and a smaller increase in osteoblastogenesis. In contrast to the effect on myeloma cells, the effect of syndecan-1 on osteoclastogenesis only requires the syndecan-1 heparan sulfate chains and not the intact ectodomain, suggesting that syndecan's effect on myeloma and bone cells occurs through different mechanisms. When injected in severe combined immune deficient (scid) mice, control-transfected myeloma cells (ARH-77 cells) expressing little syndecan-1 readily form tumors, leading to hind limb paralysis and lytic bone disease. However, after the injection of syndecan-1–transfected ARH-77 cells, the development of disease-related morbidity and lytic bone disease is significantly inhibited. Taken together, our data demonstrate, both in vitro and in vivo, that syndecan-1 has a significant beneficial effect on the behavior of both myeloma and bone cells and therefore may represent one of the central molecules in the regulation of myeloma pathobiology.

Small Leucine-Rich Proteoglycans (SLRPs) Are Involved in the Anti-Myeloma Response of Osteoblasts.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 815-815
Author(s):  
Xin Li ◽  
Angela Pennisi ◽  
Shmuel Yaccoby
Keyword(s):  
Tumor Progression ◽  
Cell Survival ◽  
Molecular Mechanism ◽  
Western Blotting ◽  
Bone Disease ◽  
Negative Impact ◽  
Conditioned Media ◽  
Osteolytic Bone Disease

Abstract Multiple myeloma (MM) is closely associated with severe osteolytic bone disease caused by stimulation of osteoclastogenesis and suppression of osteoblastogenesis. We have recently demonstrated that while osteoclasts support MM growth, osteoblasts have negative impact on survival and proliferation of MM cells from a subset of patients in vitro and in vivo (Yaccoby et al., Cancer Res 2004: Haematologica 2006), indicating that MM bone disease drives tumor progression. To unravel anti-MM molecular mechanism of osteoblasts we performed global gene expression profiling on osteoblasts and their precursors, mesenchymal stem cells (MSCs). We found and validated by qRT-PCR and Western Blotting that osteoblasts produce high level of small leucine-rich proteoglycans (SLRPs). Main SLRPs such as decorin, biglycan and lumican are essential for proper bone remodeling have been shown to inhibit growth of various tumors and their expression is inversely correlated with tumor progression. Decorin is not produced by most MM cases and recombinant decorin was rapidly internalized by MM cells. Co-culture of MM cells with the supporting osteoclasts in the presence of osteoblast’s conditioned media resulted in reduced MM cell survival (n=5, p<0.002), an effect that was partially but significantly attenuated by decorin neutralizing antibody (5 μg/ml, n=5, p<0.01). In co-culture with osteoblasts, primary MM cell growth was significantly increased by 46±15% when decorin expression in osteoblasts was effectively blocked using lentiviral-containing decorin siRNA (n=4, p<0.04). In contrast overexpression of decorin in MSCs resulted in reduced primary MM cell survival by 20±3% (n=4, p<0.04). Furthermore, in co-culture with osteoclasts recombinant or purified decorin (5–10 μg/ml) inhibited growth of primary MM cells in 6 of 9 experiments by 35±8% (p<0.007). The anti-MM effect of decorin involved direct induction of apoptosis as determined by annexin V/PI flow cytometry and activation of p21 using Western Blotting. In additional experiments we demonstrated that conditioned media from culture of MM cells stimulated tube formation by HUVECs in a matrigel assay and that decorin significantly attenuated this effect (2±1 vs. 12±1 tubes in control wells, p<0.001), indicating that certain SLRPs are antiangiogenic. Decorin (5–10 μg/ml) also effectively inhibited differentiation of osteoclasts in culture of osteoclast precursors with RANKL and M-CSF (14±2 vs. 32±4 multinucleated TRAP-expressing osteoclasts in control wells, p<0.01). For in vivo study we exploited our SCID-hu model for primary MM (Yaccoby et al., Blood 1998: 1999). Immunohistochemical analysis for decorin and lumican in nonmyelomatous human bone implanted in SCID-hu mice revealed high expression level by osteogenic cells and localization along the bone surface and extracellular matrix. Decorin and lumican levels were reduced in myelomatous bones engrafted with primary MM cells and markedly increased following treatment with osteoblast activating agents such as PTH and anti-DKK1, providing a possible molecular mechanism for anti-MM efficacy of these agents in vivo (Yaccoby et al., Blood 2007). We conclude that certain SLRPs are involved in the anti-MM effect of mature osteoblasts directly and indirectly through inhibition of angiogenesis and osteoclastogenesis, and that increasing endogenous or exogenous SLRPs in myelomatous bones are safe approaches to control MM and its associated bone disease.

Zoledronate Exerts Direct Antiproliferative and Apoptotic Effects on Human Myeloma Cells In Vitro and In Vivo.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3387-3387
Author(s):  
Andreas Guenther ◽  
Sharon Gordon ◽  
Frank Bakker ◽  
Renate Burger ◽  
Markus Tiemann ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Specific Effect ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Control Group ◽  
Dependent Manner ◽  
Myeloma Cells ◽  
Osteolytic Bone Disease

Abstract Zoledronate (ZOL) is the most potent nitrogen-containing bisphosphonate and is effective at preventing osteolytic bone disease in patients with multiple myeloma (MM) and solid tumors. ZOL inhibits the enzyme farnesylpyrophosphate synthase and thus blocks the prenylation of small GTPases. In vitro studies have demonstrated that ZOL can also directly affect the growth and viability of myeloma cells, however, the molecular mechanisms underlying this activity have not been fully elucidated. The goal of our study was to investigate direct antimyeloma effects of ZOL in vitro and in vivo. In five myeloma cell lines (RPMI8226, L363, U266, JK-6L, and the IL-6 dependent INA-6), growth was inhibited and apoptosis induced by ZOL in a dose-dependent manner (IC50’s between 30 μM and 285 μM). Similar results were obtained in the presence of bone marrow stromal cells, IL-6 (20 ng/mL), IGF-1 (200 ng/mL), or a combination of both cytokines. The potential antitumor effect of ZOL on myeloma cells in vivo was studied in the INA-6 SCID model, in which mice are injected intraperitoneally with INA-6 cells and subsequently develop plasmacytomas. Mice treated with ZOL had reduced tumor burden and a significant survival benefit compared to the control group (p=0.002). Histological examination of plasmacytomas explanted 72 hours after a single injection of 8 μg ZOL revealed extensive apoptotic/necrotic areas while no such areas were found in tumors of untreated animals. Induction of apoptosis was confirmed by Western blot analysis of tumor lysates, which revealed increased levels of cleaved poly (ADP-ribose) polymerase (PARP) in tumors of ZOL treated vs. untreated animals. This correlated with an accumulation of the unprenylated form of the small GTPase Rap1A, which was virtually absent in tumors of untreated mice. Our findings demonstrate a direct and specific effect of ZOL in plasmacytomas in vitro and in vivo and point to a therapeutic potential in MM beyond the prevention of osteolytic lesions.

Deregulated Cellular Iron Metabolism Factors Mediate Iron Overload in Myeloma Cells and Osteoclasts, and Promote Myeloma Growth and Bone Disease,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3941-3941
Author(s):  
Rakesh Bam ◽  
Wen Ling ◽  
Sharmin Khan ◽  
Sathisha Upparahalli Venkateshaiah ◽  
Xin Li ◽  
...  
Keyword(s):  
Cell Growth ◽  
Iron Overload ◽  
Iron Metabolism ◽  
Bone Disease ◽  
Iron Chelator ◽  
Myeloma Cell ◽  
High Energy ◽  
Myeloma Cells

Abstract Abstract 3941 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. Disclosures: Barlogie: Celgene, Genzyme, Novartis, Millennium: Consultancy, Honoraria, Patents & Royalties. Shaughnessy:Myeloma Health, Celgene, Genzyme, Novartis: Consultancy, Employment, Equity Ownership, Honoraria, Patents & Royalties.

scholarly journals An Improved Animal Model of Multiple Myeloma Bone Disease

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 31-31
Author(s):  
Syed Mehdi ◽  
Maurizio Zangari ◽  
Donghoon Yong
Keyword(s):  
Multiple Myeloma ◽  
Lumbar Spine ◽  
Bone Disease ◽  
Therapeutic Effects ◽  
Myeloma Cells ◽  
Tail Vein ◽  
Significant Difference ◽  
Osteolytic Bone Disease ◽  
Nsg Mouse

Multiple myeloma (MM) is a plasma cell malignancy that represents an accumulation of terminally differentiated monoclonal plasma cells (PCs) in the bone marrow (BM), accompanied by increased osteoclasts and decreased osteoblasts in areas adjacent to myeloma cells, leading to MM associated bone disease (MMBD). Osteolytic bone disease is one of the defining features of MM. During the disease, over 90% of patients are developing MMBD. Many of MM animal models have been developed and enable us to interrogate the mechanisms of MM tumorigenesis. Most MMBD models were derived by intratibial injection of myeloma cells. In these models, osteolysis occurs locally at the site where myeloma cells were injected. Mouse myeloma cells, 5TGM1 transplanting C57BL/KaLwRij mouse via the tail vein develops and shows MMBD features close to human MMBD. Even in this model, the MMBD levels on each mouse are widely varied. Lack of appropriate in vivo MMBD model hampers our understanding of the disease and developing therapy. We try to establish a murine model for MMBD to study its pathophysiology and test a novel treatment. 1x106 luciferase-expressing 5TGM1 (5TGM1-Luc) cells were injected into 8-12 week old NOD SCID gamma mouse (NSG) and C57BL/KaLwRij mouse via the tail vein. Myeloma progression was weekly assessed by in vivo bioluminescence (BL) imaging using IVIS-200 (Perkin Elmer). Mice were sacrificed when they showed endpoint signals such as significant weight loss, hindlimb paralysis, etc.. At postmortem, the micro-computer tomography (micro-CT) was performed for bone histo-morphometric analyses using micro CT400, Scano medical, Inc. The median survival was 56 days in NSG, while 42 days in C57BL/KaLwRij. In vivo BL image analysis showed that myeloma slowly develops in NSG mouse in comparison to C57BL/KaLwRij mouse. Histomorphic analyses found that severe osteolytic lesions occur at the lumbar spine in NSG mouse compared to C57BL/KaLwRij mouse, but no significant difference at the femur of both strains. At the lumbar spine, trabecular thickness (p &lt; 0.0004) and trabecular space (p &lt; 0.0014) were significantly increased in NSG mouse compared to C57BL/KaLwRij mouse. On the contrary, trabecular number (p &lt; 0.0002) and bone volume density (p &lt; 0.0005) were significantly decreased in NSG mouse compared to C57BL/KaLwRij mouse. In conclusion, we found that the systemic 5TGM1 injected NSG mouse slowly progresses myeloma and develops more severe MMBD than C57BL/KaLwRij model. This model will serve a better MMBD model to evaluate the therapeutic effects of MMBD targeted drugs. Disclosures No relevant conflicts of interest to declare.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Sign in / Sign up

Export Citation Format

Share Document