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Experimental Therapeutics |
B-IgG Fc Fusion Protein in Suppressing Bone Resorption and Hypercalcemia in a Model of Humoral Hypercalcemia of Malignancy1
Division of Endocrinology, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 [B. O. O., K. T., P. J. W., T. Y., G. R. M.], and Department of Molecular Biology, Immunex Corporation, Seattle, Washington 98101 [D. M. A.]
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ABSTRACT |
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 Top ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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B (RANK) is a membrane-bound tumor necrosis factor receptor homologue that mediates signals obligatory for osteoclastogenesis as well as osteoclast activation and survival in vivo. The present study was undertaken to evaluate the efficacy of a soluble murine RANK-human immunoglobulin fusion protein (muRANK.Fc) as a bone resorption inhibitor in vitro and in vivo. The in vitro studies demonstrated the ability of muRANK.Fc to inhibit human parathyroid hormone-related protein (PTHrP)-induced resorption in fetal rat long bone cultures. Short-term administration of muRANK.Fc to normal growing mice resulted in a complete disappearance of osteoclasts from metaphyses of long bones associated with a pronounced increase in calcified trabeculae and bone radiodensity. In a model of humoral hypercalcemia of malignancy in which PTHrP secreted by s.c. xenografts of human lung cancer in nude mice induces extensive osteolysis and severe hypercalcemia, daily administration of muRANK.Fc from time of tumor implantation profoundly inhibited osteoclastic bone resorption and prevented hypercalcemia. muRANK.Fc had no effect on tumor production of PTHrP, because there was no significant difference between circulating human PTHrP levels in muRANK.Fc-treated and vehicle-treated tumor-bearing mice. Moreover, even when treatment was initiated after hypercalcemia was established, muRANK.Fc significantly attenuated further increases in blood ionized calcium. These data demonstrate the potent antiresorptive effects of muRANK.Fc in vivo as well as highlight the potential utility of disrupting RANK signaling as a novel therapeutic approach in humoral hypercalcemia of malignancy and possibly multiple myeloma and skeletal metastases associated with osteolysis. |
INTRODUCTION |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Solid tumors such as SCC of the lung and renal cell carcinomas are frequently associated with a paraneoplastic syndrome that includes severe and often life-threatening hypercalcemia attributable to markedly enhanced osteoclast-mediated bone resorption and renal tubular calcium conservation (18, 19, 20, 21, 22)
. Although the tumors themselves do not frequently metastasize to bone, there is usually an increase in the number and activity of osteoclasts at distant skeletal sites (19)
. The increased osteoclastogenesis and osteoclast activation is mediated in most cases by proresorptive factors produced by primary tumor cells, which circulate systemically. The most commonly associated mediator is PTHrP, which is present in increased amounts in 80% of hypercalcemia patients with solid tumors. There is evidence that PTHrP may act independently or in concert with other tumor-produced proresorptive cytokines such as IL-l
, IL-6, TNF-, and transforming growth factor- (reviewed in Refs. 18
, 19
). Nevertheless, it is likely that RANKL is the common downstream mediator of the excessive bone resorption in this syndrome, commonly termed HHM, because RANKL expression by bone marrow stromal/osteoblastic cells has been shown to be modulated by PTHrP and these cytokines (14
, 15
; reviewed in Refs. 3
, 4
). Moreover, the exaggerated osteoclast-mediated bone resorption and hypercalcemia normally induced by the administration of PTHrP, TNF-, and IL-1 to rodents was completely abrogated in RANK knockout mice challenged with these calciotropic cytokines (12)
. Interestingly, we and others have also reported that several human SCC cell lines associated with severe humoral hypercalcemia express RANKL constitutively (23
, 24)
. Some of these cell lines were reported to encode a naturally secreted form of RANKL that is biologically active in stimulating osteoclastogenesis in vitro (24)
. Thus, an effective blockade of RANKL-induced signaling would represent a novel therapeutic strategy in the clinical management of HHM.
A recombinant soluble form of human RANK, representing the entire extracellular domain expressed as a fusion protein with human IgG Fc, has been shown to act as a functional antagonist of RANK-mediated signaling in vitro (1) . RANK.Fc-expressing transgenic mice develop a similar phenotype to transgenic mice overexpressing OPG with mild osteopetrosis and delay in tooth eruption (25) . These features, which are attributable to a marked reduction in formation of osteoclasts from hematopoietic precursors as well as dysfunction of the few osteoclasts formed, result overall in marked reduction in osteoclast-mediated bone modeling and remodeling. These data strongly suggest that exogenously administered RANK.Fc would sequester endogenous RANKL, and prevent RANKL-induced signaling via RANK in vivo. The present study was undertaken to evaluate the efficacy of a soluble version of murine RANK (muRANK.Fc), similarly expressed as a fusion protein with human IgG Fc, in inhibiting osteoclast-mediated bone resorption in vivo and thereby preventing hypercalcemia in a mouse model of HHM.
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MATERIALS AND METHODS |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Fetal Rat Long Bone Assay
To assess bone resorption, 45Ca release assay was performed using fetuses from timed pregnant Sprague Dawley rats (day 18 gestation; Harlan Sprague Dawley, San Diego, CA) that received injections s.c. with 250 µCi of [45Ca]calcium chloride (ICN Biomedicals, Irvine, CA) 24 h before assay, as described previously (26)
. Explanted radiolabeled long bone rudiments (
1 mm x 2 mm x 1 mm) were incubated in the presence or absence of recombinant human PTHrP(1–34) (Bachem, King of Prussia, PA) and/or muRANK.Fc for 5 days. Culture media were replenished every 48 h, and the expended media were saved. At the end of the culture period, radioactivity in both the media and trichloroacetic acid extracts of the bones were determined separately by liquid scintillation counting. Radioactivity in the media harvested at earlier time points was combined with that of the final conditioned media and represented the total medium count. The amount of 45Ca released (cpm) from individual bones over the total 5-day culture period (total medium cpm) was calculated as a percentage of total radioactivity (total medium cpm + residual bone cpm).
Radiographic Analysis
High resolution whole body radiographs of ketamine-anesthetized mice were obtained with the animals in a prone position on Kodak X-Omat AR radiographic film (Eastman Kodak, Rochester, NY) using a Faxitron Cabinet X-ray unit (Faxitron X-ray Corp., Buffalo, IL).
Human Xenografts
Animal studies were conducted using weight-matched 4–6-week-old (18–22 g) female BALB/c athymic nude mice (homozygous, nu/nu; Harlan). All of the studies were approved by the University of Texas Health Science Center at San Antonio Institutional Animal Care and Use Committee and conducted in accordance with the NIH Guide for the Care and Use of Laboratory Animals. The establishment of the human lung SCC cell line (RWGT2) from explanted metastatic tumor tissue obtained from a severely hypercalcemic patient has been described previously (26)
. RWGT2 cells were maintained as adherent cultures in DMEM supplemented with 10% fetal bovine serum (Summit Biotechnology, Fort Collins, CO), 1% glutamine, and antibiotics. Cultured cells were harvested by trypsinization and resuspended in HBSS. Aliquots of these (1 x 106 cells/200 µl) were inoculated into the s.c. tissue over the right flank of mice that subsequently developed tumors and became hypercalcemic. Xenografts were maintained in vivo in nude mice by sequential transplantation. After three successive passages, tumor tissue aseptically excised from a severely hypercalcemic tumor-bearing mouse ([Ca2+] > 2 mmol/liter) was finely minced and suspended in HBSS. Tumor fragments (15 mm3) were then xenotransplanted s.c. in male athymic nude mice 4 weeks of age.
Experimental Design
Two separate treatment protocols were used in this study.
Protocol I: Prevention of RWGT2 Tumor Xenograft-associated Hypercalcemia.
Animals were inoculated with RWGT2 tumor fragments on day 0 as described above. The tumor-bearing mice were then randomly assigned to two groups; one group received muRANK.Fc administered over the flank as a once daily s.c. injection (see Fig. 3A
) and the other group received the vehicle (HBSS, 50 µl/day) from day 1 for a total of 21 days. As controls, nontumor-bearing mice were treated as above.
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Human PTHrP Assay
Plasma PTHrP levels were determined in duplicates using a two-site IRMA for the intact molecule (Nichols Institute, San Juan, CA) according to the manufacturer’s protocol. Blood was drawn by orbital sinus puncture just before sacrifice and collected on ice into EDTA-containing vacutainer tubes (Becton Dickinson, Rutherford, NJ). To inhibit proteolysis, aprotinin (400 IU) was immediately added, and samples were centrifuged at 4°C for 10 min. Plasma samples were stored at -70°C until assayed.
Histological and Histomorphometric Analyses
Tumor-bearing animals as well as control nontumor-bearing mice were sacrificed at day 22 after tumor inoculation by cervical dislocation after ketamine-induced anesthesia. The long bones and spines were removed, fixed in 10% buffered formalin for 48 h, decalcified in EDTA, embedded in paraffin, and sectioned along the midsagittal plane at 7 µm. The bone sections were stained with H&E, and histomorphometric analyses were carried out as described (27)
. Serial sections of tibiae and femora were also stained for TRAP activity to reveal osteoclasts.
Statistical Analysis
Data from the bone resorption assay were analyzed by one-way ANOVA with post hoc testing using Fisher’s Protected Least Significant Difference test (StatView 5.0.1; SAS Institute, Inc., Cary, NC). Mann-Whitney U test for nonparametric data (StatView) was used to assess the significance of the difference in ionized calcium levels and areas under the dosing curve between muRANK.Fc-treated and vehicle-treated animals.
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RESULTS |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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. This effect was also observed in other regions of the appendicular skeleton as assessed in whole body radiographs (data not shown). Histological evaluation of sections of the tibiae and femora of muRANK.Fc-treated mice revealed widening of the primary spongiosa subjacent to the growth plate with a pronounced increase in the amount and connectivity of newly formed metaphyseal cancellous bone tissue (Fig. 2D)
.
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. Fig. 3B
shows the effect of muRANK.Fc treatment on whole blood ionized calcium levels. Fig. 4
presents the histological changes, and Fig. 5
shows the static histomorphometric findings in bone attributable to muRANK.Fc treatment. RWGT2 xenograft-bearing mice that received vehicle developed rapidly increasing blood ionized calcium levels from the beginning of the third week with full-blown hypercalcemia by day 22. In contrast, muRANK.Fc-treated tumor-bearing mice had only a marginal increase in blood ionized calcium even at the end of the experiment. Both vehicle-treated and muRANK.Fc-treated nontumor-bearing mice remained normocalcemic for the duration of treatment (data not shown). There was no difference in circulating PTHrP between the two tumor-bearing groups, because PTHrP concentrations in mouse plasma samples, measured by a human PTHrP-specific IRMA, were comparable (data not shown). No human PTHrP was detected in the plasma of control nontumor-bearing mice. There was no beneficial effect of muRANK.Fc on either tumor xenograft size or loss of body weight (data not shown). Representative histological sections of long bones of the hind limbs of vehicle-treated tumor-bearing mice revealed TRAP+ osteoclasts that were especially prominent at the junction of the metaphyseal aspect of the growth plates and the primary spongiosa (Fig. 4, E and F)
. Unlike nontumor-bearing control mice where osteoclastic activity was restricted to this region (data not shown), there were abundant intensely stained TRAP+ osteoclasts lining bone surfaces at a distance from the primary spongiosa in vehicle-treated tumor-bearing mice, reflecting the osteoclastogenic effect of PTHrP (Fig. 4C
compare Fig. 4F
). In marked contrast, trabecular bone surfaces in muRANK.Fc-treated tumor-bearing mice were almost completely devoid of osteoclasts (Fig. 4, H and I)
. Quantitative histomorphometric analysis showed that cancellous bone volumes in tumor-bearing mice treated with muRANK.Fc were significantly higher by the end of the experiment than in tumor-bearing mice treated with vehicle. Indeed, bone volumes in muRANK.Fc-treated tumor-bearing mice were comparable with cancellous bone volumes in normal nontumor-bearing (untreated control) mice (Fig. 5A)
. Consistent with these histological observations, there was a virtual disappearance of osteoclasts and active bone-resorbing surfaces in muRANK.Fc-treated animals (Fig. 5B)
.
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. Although there was no difference in the mean calcium levels between the two groups of mice that received saline control when compared with the group that received muRANK.Fc, the percentage of increase in ionized calcium at the end of the 8-day treatment period was significantly less in the muRANK.Fc-treated group compared with the vehicle-treated group [1.76 ± 0.07 mM, muRANK.Fc versus 1.99 ± 0.2 mM, vehicle (
11% compare 41%; Fig. 6B
)], as was the area under the dosing curve (data not shown). |
DISCUSSION |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Short-term treatment of normal, rapidly growing mice with muRANK.Fc for 6 days resulted in dramatic changes in bone resorption with almost complete disappearance of osteoclasts from trabecular surfaces as assessed by cytoplasmic TRAP staining. It is interesting to note that bone modeling was also altered, resulting in a substantial increase in the amount of cancellous bone tissue in proximal tibial and distal femoral metaphyses manifesting as markedly enhanced density of these regions on radiographic examination. Given this potent ability of muRANK.Fc to inhibit bone resorption in vivo, we assessed its efficacy in suppressing tumor-induced osteolysis, thereby preventing the development of hypercalcemia or limiting further rise in blood ionized calcium levels once hypercalcemia is established. To this end, we used a well-characterized animal model of HHM that involves transplantable human lung SCC tumor cells (RWGT2), which secrete PTHrP in vitro as well as in vivo. Severe hypercalcemia develops in nude mice bearing RWGT2 tumor xenografts between 2 and 3 weeks of tumor implantation, primarily because of excess circulating tumor cell-produced human PTHrP (22) . When daily treatment was initiated from the time of tumor inoculation and continued for the duration of the experiment, muRANK.Fc prevented the expected rise in whole blood ionized calcium, and this was associated with an increase in cancellous bone volume and markedly decreased osteoclast numbers on bone surfaces. The average tumor size and circulating PTHrP levels in the muRANK.Fc-treated tumor-bearing mice were not different from those of the vehicle-treated group, arguing against the possibility that these parameters influenced ionized calcium levels. PTHrP was assayed using an IRMA, which does not cross-react with mouse PTHrP. Consistent with this, no PTHrP was detected in the plasma of control nontumor-bearing mice, clearly indicating that measured PTHrP in the tumor-bearing groups originated from the human tumor xenografts. Together, these data strongly indicate that muRANK.Fc suppresses bone loss in RWGT2 tumor-bearing mice by inhibiting osteoclast activity.
Despite the continued daily administration of muRANK.Fc, blood ionized calcium appeared to start to rise in the last 2 days in the treated mice, such that it was marginally above the upper limit of the normal reference range on day 22. In considering likely explanations for this observation, it should be borne in mind that muRANK.Fc had no effect on rates of growth of the xenografts, because tumor volumes in muRANK.Fc-treated mice assessed at different time points were not significantly different from those in the vehicle-treated group. The continued tumor growth, unabated PTHrP production, and the consequent high circulating levels of PTHrP would serve to increase renal tubular calcium reabsorption, thus contributing to blood ionized calcium despite the complete suppression of osteoclast-mediated bone resorption. The complete disappearance of osteoclasts from the bones of the muRANK.Fc-treated animals observed at the end of the experiment clearly indicates that the marginal increase in blood ionized calcium observed at the end of the treatment period cannot be ascribed to ongoing osteoclastic bone resorption. Alternatively, the marginal increase in blood ionized calcium may reflect a 1,25(OH)2D3-mediated increase in intestinal calcium absorption, because it is known that infusions of PTHrP in nude mice stimulate renal 1 hydroxylase activity resulting in increased serum 1,25(OH)2D3 levels (19)
.
We also verified that muRANK.Fc was efficacious even when treatment is initiated after the onset of hypercalcemia in this experimental model. Although the increase in blood ionized calcium in RWGT2-tumor bearing mice with established hypercalcemia was significantly attenuated after daily parenteral administration of muRANK.Fc, it was not completely suppressed. Histological analysis of the bones revealed an almost complete absence of osteoclasts in the muRANK.Fc group. Thus, the failure to achieve complete suppression of the rise in ionized calcium is likely because of extra-osseous effects of the very high circulating levels of PTHrP.
OPG and its derivative OPG.Fc, which also bind RANKL and thereby prevent its interaction with its signaling receptor RANK, have also been reported to decrease serum calcium levels in murine xenogeneic and syngeneic models of HHM involving PTHrP (29 , 30) . One feature that distinguishes RANK and its derivative muRANK.Fc from OPG is that RANK binds only to RANKL (1) , whereas OPG and OPG.Fc bind additionally to TRAIL, a ubiquitously expressed membrane-bound TNF homologue (31) . Although the physiological significance of TRAIL binding to OPG in vivo is presently unknown, there is a distinct possibility that any beneficial effect of OPG in inhibiting osteoclastic bone resorption in malignancy-induced osteolysis may be abrogated to some degree by the effects of TRAIL on its osteoclastogenesis-inhibitory activity (31) . Thus, development of an alternative "decoy receptor" to OPG, such as RANK.Fc, that is equally effective in inhibiting RANKL-mediated osteoclastic bone resorption without these potential complications is a desirable objective.
In our experiments, there was no overt toxicity seen with muRANK.Fc, which is consistent with the observation that transgenic mice expressing a soluble form of RANK.Fc exhibit no gross phenotypic abnormalities other than mild osteopetrosis attributable to a marked reduction in number, size, and function of osteoclasts (25) . Current therapies for tumor-induced osteolysis and hypercalcemia are based on BPs (32) , which inhibit bone resorption in vitro and in vivo largely by inducing osteoclast apoptosis (33) . However, there are dose-related toxicity issues with BPs, and side effects are increasingly being reported (34) . Moreover, on the basis of studies in animal models of osteolytic bone metastases, there has been concern recently that newer generation BPs, albeit more potent as antiresorptives, may concomitantly increase visceral metastases (35 , 36) . Thus, preclinical development of a similarly soluble form of human RANK expressed as a fusion protein (huRANK.Fc) as an alternative to BPs would provide a therapeutic option in the management of tumor-induced osteolysis. Beyond these, the data presented herein also strongly suggest that RANK.Fc may also provide protection from the bone destruction commonly associated with multiple myeloma and tumors metastatic to the skeleton such as breast cancer. Indeed, in recent preliminary studies, we and others have confirmed the efficacy of muRANK.Fc in inhibiting the development and progression of osteolytic lesions in various in vivo models of human myeloma bone disease (37 , 38) . We are currently evaluating its effects on osteolysis in animal models of human breast cancer skeletal metastases.
In summary, muRANK.Fc, a truncated form of murine RANK genetically engineered as a soluble molecule fused to the Fc domain of human IgG1, profoundly inhibited osteoclastic bone resorption both in vitro and in vivo in a well-characterized model of HHM that is reasonably predictive of clinical efficacy. Parenteral administration of muRANK.Fc from the time of tumor inoculation abrogated the expected PTHrP-induced elevation in blood ionized calcium in human SCC (RWGT2) tumor-bearing mice. Furthermore, muRANK.Fc also slowed the rise in blood ionized calcium in RWGT2 tumor-bearing mice with established and progressive hypercalcemia. The profound suppression of osteoclastic bone resorption induced by muRANK.Fc appears to underlie its efficacy in this regard. Overall, these findings support the hypothesis that the effects of PTHrP in bone in HHM are mediated via RANK signaling. These data also validate the concept that targeting RANKL/RANK interaction and/or the signaling pathways downstream of this interaction would be effective antiresorptive therapeutic strategies for tumor-induced hypercalcemia.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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1 Supported by Grants from the NIH to G. R. M. (PO1-CA40035) and from the San Antonio Cancer Institute (a National Cancer Institute-designated Comprehensive Cancer Center) to B. O. O. (P30-CA54174). Dr. Oyajobi was a recipient of a 1999 Brian D. Novis Fellowship from The International Myeloma Foundation. Parts of this work were presented at the 21st Annual Meeting of the American Society for Bone and Mineral Research, St. Louis, Missouri, September 1999 and have appeared in abstract form [J. Bone Miner. Res., 14 (Suppl.): 163, 1999]. 
2 To whom requests for reprints should be addressed, at Department of Medicine/Endocrinology (Mailcode 7877), University of Texas, Health Science Center at San Antonio, San Antonio, TX 78229-3900. Phone: (210) 567-4919; Fax: (210) 567-6693; E-mail: oyajobi{at}uthscsa.edu
3 The abbreviations used are: RANK, receptor activator of nuclear factor B; TNF, tumor necrosis factor; PTHrP, parathyroid hormone-related protein; IL, interleukin; HHM, humoral hypercalcemia of malignancy; TNFRSF, TNF receptor superfamily; RANKL, RANK ligand; TNFSF, TNF superfamily; OPG, osteoprotegerin; SCC, squamous cell carcinoma; TRAP, tartrate-resistant acid phosphatase; IRMA, immunoradiometric assay; TRAIL, TNF-related apoptosis-inducing ligand; BP, aminobisphosphonates; BV, bone volume; TV, total volume.
4 D. M. Anderson and K. Charrier, unpublished data.
Received 10/17/00. Accepted 1/12/01.
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REFERENCES |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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b ligand and osteoprotegerin in the pathogenesis and treatment of metabolic bone diseases. J. Clin. Endocrinol. Metab., 85: 2355-2363, 2000.B ligand and stimulation of osteoclastogenesis by gp130-utilizing cytokines or interleukin-1 but not 1,25- dihydroxyvitamin D3 or parathyroid hormone. J. Biol. Chem., 274: 19310-19318, 1999.
B ligand and M-CSF by human squamous cell carcinoma cells. Bone, 23 (Suppl.): S192 1998.
enhance hypercalcemia in vivo and bone resorption in vitro. J. Clin. Endocrinol. Metab., 77: 40-45, 1993.[Abstract]
B-human immunoglobulin fusion protein (RANK.Fc) inhibits bone resorption in a murine model of human multiple myeloma bone disease. J. Bone Miner. Res., 15 (Suppl. 1): S176 2000.
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), n = 7; muRANK.Fc (•), n = 8]. *, P < 0.05, significant difference from the group treated with vehicle. ····, upper limit of reference range for whole blood ionized calcium in normal athymic nude mice (1.3 mmol/liter).
) and/or muRANK.Fc. Data are expressed as mean ± SE for four to five cultures/group. PTHrP-induced 45Ca release was significantly inhibited in the presence of muRANK.Fc. (
, P < 0.001) versus PTHrP-induced 45Ca release in its absence. Basal 45Ca release (
) was also significantly reduced in the presence of muRANK.Fc (
; *, P < 0.05).
