Heparanase Expression Correlates with Bone Destruction in the Patients with Multiple Myeloma

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1813-1813 ◽  
Author(s):  
Shi Wei ◽  
Racquel Innis-Shelton ◽  
Li Nan ◽  
Jian Ruan ◽  
Rebecca S Sollie ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Bone Disease ◽  
Bone Marrow Cells ◽  
Bone Destruction ◽  
Bone Lesions ◽  
Bone Marrow Biopsies ◽  
Myeloma Cells ◽  
Lytic Bone Lesions ◽  
Marrow Cells

Abstract Abstract 1813 Multiple myeloma is an incurable malignancy, and excessive bone destruction is a major cause of morbidity in myeloma patients. However, the biologic mechanisms involved in the pathogenesis of myeloma-induced bone disease are poorly understood. Heparanase, an enzyme that cleaves the heparan sulfate chains of proteoglycans, is upregulated in a variety of human tumors, including myeloma. In the present study, bone marrow biopsies from 40 myeloma patients were stained with antibodies raised against heparanase, RANKL (an osteoclastogenic cytokine), OPG (a decoy receptor for RANKL), TRAP (a marker of osteoclastogenesis) and osteocalcin (a marker of osteoblastogenesis). The radiologic studies for bone lesions of these patients were also recorded. We analyzed the correlations between heparanase expression in bone marrow myeloma cells with (1) the numbers of TRAP positive osteoclasts, (2) RANKL and OPG expression in myeloma cells and osteoblastic cells, (3) the numbers of osteocalcin positive osteoblasts in bone marrow, and (4) the presence/absence of lytic bone lesions. We found a positive correlation between heparanase expression and RANKL expression as well as the numbers of TRAP positive osteoclasts in myeloma and bone marrow cells, but no correlation was found between the expressions of heparanase and OPG in bone marrow cells (myeloma cells do not express OPG). In contrast, heparanase expression was negatively correlated with the numbers of osteocalcin positive osteoblasts. Taken together, these data suggest that heparanase expression by myeloma cells promotes osteoclastogenesis and at same time inhibits osteoblastogenesis. Clinical data show that 92% of patients with high level of heparanase had one or more lytic bone lesions, while only 63% of patients with median∼ low levels of heparanase had bone lesions (p<0.0001). In summary, enhanced heparanase expression in myeloma cells promotes bone resorption and inhibits bone formation; these events contribute to the uncontrolled bone destruction that is characteristic of myeloma. These data provide novel insight into the mechanisms driving myeloma bone disease and suggest that heparanase inhibitors are valid therapeutic targets for the treatment of multiple myeloma. Disclosures: No relevant conflicts of interest to declare.

Bone disease as the first manifestation of systemic AL-amyloidosis

2020 ◽  
Vol 92 (7) ◽  
pp. 85-89
Author(s):  
L. P. Mendeleeva ◽  
I. G. Rekhtina ◽  
A. M. Kovrigina ◽  
I. E. Kostina ◽  
V. A. Khyshova ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Bone Disease ◽  
Plasma Cells ◽  
Interventricular Septum ◽  
Bone Destruction ◽  
Amyloid Deposition ◽  
Bone Lesions ◽  
Al Amyloidosis ◽  
Linear Type

Our case demonstrates severe bone disease in primary AL-amyloidosis without concomitant multiple myeloma. A 30-year-old man had spontaneous vertebral fracture Th8. A computed tomography scan suggested multiple foci of lesions in all the bones. In bone marrow and resected rib werent detected any tumor cells. After 15 years from the beginning of the disease, nephrotic syndrome developed. Based on the kidney biopsy, AL-amyloidosis was confirmed. Amyloid was also detected in the bowel and bone marrow. On the indirect signs (thickening of the interventricular septum 16 mm and increased NT-proBNP 2200 pg/ml), a cardial involvement was confirmed. In the bone marrow (from three sites) was found 2.85% clonal plasma cells with immunophenotype СD138+, СD38dim, СD19-, СD117+, СD81-, СD27-, СD56-. FISH method revealed polysomy 5,9,15 in 3% of the nuclei. Serum free light chain Kappa 575 mg/l (/44.9) was detected. Multiple foci of destruction with increased metabolic activity (SUVmax 3.6) were visualized on PET-CT, and an surgical intervention biopsy was performed from two foci. The number of plasma cells from the destruction foci was 2.5%, and massive amyloid deposition was detected. On CT scan foci of lesions differed from bone lesions at multiple myeloma. Bone fragments of point and linear type (button sequestration) were visualized in most of the destruction foci. The content of the lesion was low density. There was no extraossal spread from large zones of destruction. There was also spontaneous scarring of the some lesions (without therapy). Thus, the diagnosis of multiple myeloma was excluded on the basis based on x-ray signs, of the duration of osteodestructive syndrome (15 years), the absence of plasma infiltration in the bone marrow, including from foci of bone destruction by open biopsy. This observation proves the possibility of damage to the skeleton due to amyloid deposition and justifies the need to include AL-amyloidosis in the spectrum of differential diagnosis of diseases that occur with osteodestructive syndrome.

Bone morphogenetic proteins and receptors are over-expressed in bone-marrow cells of multiple myeloma patients and support myeloma cells by inducing ID genes

2010 ◽  
Vol 34 (6) ◽  
pp. 742-751 ◽  
Author(s):  
Danka Grčević ◽  
Rajko Kušec ◽  
Nataša Kovačić ◽  
Anita Lukić ◽  
Ivan Krešimir Lukić ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Bone Morphogenetic Proteins ◽  
Bone Marrow Cells ◽  
Myeloma Cells ◽  
Id Genes ◽  
Marrow Cells

scholarly journals Hypoxia-induced CREB cooperates MMSET to modify chromatin and promote DKK1 expression in multiple myeloma

Oncogene ◽  
2021 ◽  
Author(s):  
Yinyin Xu ◽  
Jing Guo ◽  
Jing Liu ◽  
Ying Xie ◽  
Xin Li ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Combined Treatment ◽  
Hypoxia Inducible Factor ◽  
Bone Destruction ◽  
Bone Lesions ◽  
Myeloma Cells ◽  
Downstream Target ◽  
Dkk1 Expression

AbstractMyeloma cells produce excessive levels of dickkopf-1 (DKK1), which mediates the inhibition of Wnt signaling in osteoblasts, leading to multiple myeloma (MM) bone disease. Nevertheless, the precise mechanisms underlying DKK1 overexpression in myeloma remain incompletely understood. Herein, we provide evidence that hypoxia promotes DKK1 expression in myeloma cells. Under hypoxic conditions, p38 kinase phosphorylated cAMP-responsive element-binding protein (CREB) and drove its nuclear import to activate DKK1 transcription. In addition, high levels of DKK1 were associated with the presence of focal bone lesions in patients with t(4;14) MM, overexpressing the histone methyltransferase MMSET, which was identified as a downstream target gene of hypoxia-inducible factor (HIF)-1α. Furthermore, we found that CREB could recruit MMSET, leading to the stabilization of HIF-1α protein and the increased dimethylation of histone H3 at lysine 36 on the DKK1 promoter. Knockdown of CREB in myeloma cells alleviated the suppression of osteoblastogenesis by myeloma-secreted DKK1 in vitro. Combined treatment with a CREB inhibitor and the hypoxia-activated prodrug TH-302 (evofosfamide) significantly reduced MM-induced bone destruction in vivo. Taken together, our findings reveal that hypoxia and a cytogenetic abnormality regulate DKK1 expression in myeloma cells, and provide an additional rationale for the development of therapeutic strategies that interrupt DKK1 to cure MM.

scholarly journals An Unprecedented Case of p190 BCR-ABL Chronic Myeloid Leukemia Diagnosed during Treatment for Multiple Myeloma: A Case Report and Review of the Literature

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Kosuke Miki ◽  
Naoshi Obara ◽  
Kenichi Makishima ◽  
Tatsuhiro Sakamoto ◽  
Manabu Kusakabe ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Plasma Cells ◽  
Bone Marrow Examination ◽  
Bone Lesions ◽  
Dexamethasone Treatment ◽  
Lytic Bone Lesions

We report the case of a 76-year-old man who was diagnosed as having chronic myeloid leukemia (CML) with p190 BCR-ABL while receiving treatment for symptomatic multiple myeloma (MM). The diagnosis of MM was based on the presence of serum M-protein, abnormal plasma cells in the bone marrow, and lytic bone lesions. The patient achieved a partial response to lenalidomide and dexamethasone treatment. However, 2 years after the diagnosis of MM, the patient developed leukocytosis with granulocytosis, anemia, and thrombocytopenia. Bone marrow examination revealed Philadelphia chromosomes and chimeric p190 BCR-ABL mRNA. Fluorescence in situ hybridization also revealed BCR-ABL-positive neutrophils in the peripheral blood, which suggested the emergence of CML with p190 BCR-ABL. The codevelopment of MM and CML is very rare, and this is the first report describing p190 BCR-ABL-type CML coexisting with MM. Moreover, we have reviewed the literature regarding the coexistence of these diseases.

scholarly journals Pivotal Role of OCL-Derived IGF1 in Drug Resistance and Bone Destruction in MM

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4336-4336
Author(s):  
Jumpei Teramachi ◽  
Kazuaki Miyagawa ◽  
Delgado-Calle Jesus ◽  
Jolene Windle ◽  
Noriyoshi Kurihara ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Drug Resistance ◽  
Bone Resorption ◽  
Bone Marrow Cells ◽  
Critical Role ◽  
Bone Destruction ◽  
Bone Marrow Microenvironment ◽  
Rank Ligand ◽  
Marrow Cells

Multiple myeloma (MM) is largely incurable, and is characterized by devastating bone destruction caused by increased osteoclast (OCL) differentiation and bone resorption in more than 85% of MM patients. OCLs in MM not only promote bone resorption but also increase MM cell growth and drug resistance. Despite recent advances in anti-myeloma treatment, development of anti-MM drug resistance is a major limitation of MM therapy. Therefore, new treatment modalities are urgently needed to overcome drug resistance and decrease bone resorption. IGF1 is a crucial factor for tumor cell growth and survival of malignant cells, especially in MM. IGFI also contributes to development of drug resistance of MM cells to anti-MM agents, including proteasome inhibitors and immunomodulatory agents, but how OCLs contribute to drug resistance is still not clearly delineated. We found that IGF1 was highly expressed in OCLs attached to bone and bone marrow myeloid cells in vivo, and the expression levels of IGF1 in OCLs from MM bearing mice is higher than in normal OCLs. Intriguingly, OCLs produced more IGF1 (0.8 ng/ml/protein) than MM cells (not detected) and bone marrow stromal cells (BMSCs) (0.4 ng/ml/protein) in vitro. In addition, IGF1 protein expression in OCLs was upregulated (1.8 fold) by treatment with conditioned media (CM) from 5TGM1 murine MM cells, TNF-α or IL-6, major paracrine factors that are increased in the bone marrow microenvironment in MM. These results suggest that OCLs are a major source of local IGF1 in the MM bone marrow microenvironment. To further characterize the role of OCL-derived IGF1, we generated a novel mouse with targeted deletion of Igf1 in OCLs (IGF1-/--OCL), and assessed the role of OCL-derived IGF1 in drug resistance of MM cells and bone destruction. Treatment of 5TGM1 cells with bortezomib (BTZ) (3 nM, 48 hours) decreased the viability of 5TGM1 cells by 50%. Importantly, the cytotoxic effects of BTZ on MM cells were decreased (by 5%) when MM cells were cocultured with OCLs from wild type (WT) mice. In contrast, coculture of MM cells with IGF1-/--OCLs or WT-OCLs treated with IGF1 neutralizing antibody (IGF1-ab) did not block BTZ's effects on MM cell death. Consistent with these results, coculture of MM cells with IGF1-/--OCLs or WT-OCLs treated with IGF1-ab resulted in BTZ-induced caspase-dependent apoptosis in MM cells. We next examined the effects of OCLs on the signaling pathways responsible for MM cell survival. WT-OCL-CM promptly induced the phosphorylation of Akt and activation of p38, ERK and NF-κB in MM cells. However, these pathways were not activated by MM cells treated with IGF1-/--OCL-CM or IGF1-ab-treated WT-OCL-CM. Since adhesion of MM cells to BMSCs via interaction of VLA-4 and VCAM-1 plays a critical role in cell adhesion-mediated drug resistance (CAMDR) in MM, we tested if treatment of human BMSCs with human OCL-CM upregulated VCAM-1 expression. We found that OCL-CM upregulated VCAM-1 expression on BMSCs (x fold). In contrast, treatment of BMSCs with OCLs treated with IGF1-ab blocked VCAM-1 induction. These data suggest that OCL-derived IGF1 can contribute to MM cell drug resistance in the bone marrow microenvironment. We then examined the role of IGF1 inhibition on osteoclastogenesis and the bone resorption capacity of OCLs. RANK ligand induced the expression of cathepsin K and NFATc1 in CD11b+ bone marrow cells from WT mice, differentiation markers of OCLs, and the formation of TRAP-positive multinucleated OCLs. However, OCLs formed by RANK ligand treatment of CD11b+ bone marrow cells from IGF1-/- mice had markedly decreased cathepsin K and NFATc1 expression and OCL formation. Next, we tested the bone resorption capacity of OCLs formed by CD11b+ bone marrow cells from IGF1-/- mice vs. WT mice. Similar numbers of OCLs were cultured with RANK ligand on bone slices for 72 hours. The bone resorption activity of Igf1-/--OCLs was significantly decreased (70%) compared with WT-OCLs. These results suggest that OCL-derived IGF1 plays a critical role in MM drug resistance and bone destruction, and that inhibition of the effect of IGF1 in OCLs should decrease MM drug resistance and bone destruction. Disclosures Roodman: Amgen trial of Denosumab versus Zoledronate: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Engraftment of dogs with Ia-positive marrow cells isolated by avidin- biotin immunoadsorption

Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1363-1367 ◽  
Author(s):  
RJ Berenson ◽  
WI Bensinger ◽  
D Kalamasz ◽  
F Schuening ◽  
HJ Deeg ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Autologous Bone Marrow Transplantation ◽  
Autologous Bone Marrow ◽  
Adherent Cells ◽  
Lymphocyte Function ◽  
Mechanical Agitation ◽  
Hematopoietic Stem ◽  
Bone Marrow Biopsies ◽  
Marrow Cells

Abstract Previous work has shown failure of engraftment in lethally irradiated dogs when autologous marrow was depleted of Ia-positive cells with an anti-Ia antibody and complement before infusion. In the current study, we have utilized an avidin-biotin immunoadsorption procedure to obtain a population of highly enriched Ia-positive cells for autologous bone marrow transplantation in dogs given lethal irradiation. Dog marrow cells (2.4 to 7.0 X 10(9) cells) that contained 8.6% to 19.9% Ia- positive cells were treated successively with monoclonal antibody 7.2, which reacts with a framework determinant of Ia-antigen, and biotin- conjugated goat antimouse immunoglobulin. These treated cells were passed over a column of avidin-Biogel (polyacrylamide) and the adherent cells removed by mechanical agitation. Seven lethally irradiated dogs were transplanted with 5.9 to 33.4 X 10(6) recovered adherent cells per kilogram of which 69.0% to 88.0% were Ia-positive. All dogs had hematologic recovery; six are alive and well with durable engraftment and one died on day 15 posttransplant. They are immunologically normal as determined by lymph node and bone marrow biopsies, lymphocyte function, and immunophenotyping of peripheral blood and bone marrow cells. These data provide further evidence that canine hematopoietic stem cells express Ia-like antigens and that these cells are capable of complete hematopoietic and immunologic reconstitution in an autologous model.

scholarly journals Increase in the Number of Bone Marrow Osteoclast Precursors at Different Skeletal Sites, Particularly in Long Bone and Jaw Marrow in Mice Lacking IL-1RA

2020 ◽  
Vol 21 (11) ◽  
pp. 3774
Author(s):  
Giuliana Ascone ◽  
Yixuan Cao ◽  
Ineke D.C. Jansen ◽  
Irene Di Ceglie ◽  
Martijn H.J. van den Bosch ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Interleukin 1 ◽  
Bone Destruction ◽  
Mineral Dissolution ◽  
Long Bone ◽  
Osteoclast Precursors ◽  
Marrow Cells

Recently, it was shown that interleukin-1β (IL-1β) has diverse stimulatory effects on different murine long bone marrow osteoclast precursors (OCPs) in vitro. In this study, interleukin-1 receptor antagonist deficient (Il1rn−/−) and wild-type (WT) mice were compared to investigate the effects of enhanced IL-1 signaling on the composition of OCPs in long bone, calvaria, vertebra, and jaw. Bone marrow cells were isolated from these sites and the percentage of early blast (CD31hi Ly-6C−), myeloid blast (CD31+ Ly-6C+), and monocyte (CD31− Ly-6Chi) OCPs was assessed by flow cytometry. At the time-point of cell isolation, Il1rn−/− mice showed no inflammation or bone destruction yet as determined by histology and microcomputed tomography. However, Il1rn−/− mice had an approximately two-fold higher percentage of OCPs in long bone and jaw marrow compared to WT. Conversely, vertebrae and calvaria marrow contained a similar composition of OCPs in both strains. Bone marrow cells were cultured with macrophage colony stimulating factor (M-CSF) and receptor of NfκB ligand (RANKL) on bone slices to assess osteoclastogenesis and on calcium phosphate-coated plates to analyze mineral dissolution. Deletion of Il1rn increased osteoclastogenesis from long bone, calvaria, and jaw marrows, and all Il1rn−/− cultures showed increased mineral dissolution compared to WT. However, osteoclast markers increased exclusively in Il1rn−/− osteoclasts from long bone and jaw. Collectively, these findings indicate that a lack of IL-1RA increases the numbers of OCPs in vivo, particularly in long bone and jaw, where rheumatoid arthritis and periodontitis develop. Thus, increased bone loss at these sites may be triggered by a larger pool of OCPs due to the disruption of IL-1 inhibitors.

What Is Important Factor of Bone Disease in Multiple Myeloma?.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4855-4855
Author(s):  
Shoso Munemasa ◽  
Akira Sakai ◽  
Yoshiko Okikawa ◽  
Yoshiaki Kuroda ◽  
Yuta Katayama ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cyclin D1 ◽  
Bone Disease ◽  
Tissue Growth ◽  
Good Survival ◽  
Bone Lesions ◽  
Rt Pcr ◽  
Myeloma Cells ◽  
Significant Difference ◽  
Chromosome 13Q

Abstract New International Prognostic Index (IPI) staging system of multiple myeloma (MM) is a combination of the level of serum β2-microglobulin and serum albumin. Particularly, good survival (median survival &gt;5 years) is associated with absence of chromosome 13q deletion. Recently, correlations between molecular subtypes and prognosis have been identified as a good prognosis with t(11;14) and a poor prognosis with t(4;14) and t(14;16) besides chromosome 13 abnormalities. We have reported that some MM cases with cyclin D1 overexpression detected by competitive RT-PCR were not caused by t(11;14)(q13;q32) or extra copies of 11q13 (In J Oncol, in press). A recent report revealed that subtypes of MM cases with the translocation of cyclin D showed a close correlation with bone disease and high level of DKK1. We also have been studing about the correlation between bone disease and bone morphogenetic protein (BMP) 2, or connective tissue growth factor (CTGF) that is supposed to inhibit the VEGF binding to its receptor or modulate cell signaling by BMP. First, we analyzed IPI staging in 91 MM cases, and then analyzed the relation between IPI staging and existence of cyclin D1 overexpression, or t(11;14)(q13;q32) and extra copies of 11q13. Competitive RT-PCR was performed in 77 cases, and cyclin D1 overexpression was detected in 40/77 (52%). Deletion of chromosome 13q was detected in 32/87 (37%), and t(11;14)(q13;q32) or extra copies of 11q13 was detected in 11/50 (22%) and 7/50 (14%), respectively. There were no significant differences of those factors among IPI staging. And we analyzed the scale of bone lesion by bone x-ray in 81 cases. We could not detect the relation between bone disease and cyclin D1 overexpression or translocation of 11q13. Furthermore, we analyzed the expression of BMP2 and CTGF by quantitative real time-PCR in purified myeloma cells or in bone marrow mononuclear cells (BMMNC) reduced myeloma cells less than 5%. We have gotten results that MM cases have a tendency to show higher CTGF expression in BMMNC compared with that of normal BM, but there was no significant difference of BMP2 expression in BMMNC between them. And there was no correlation between cyclin D1 overexpression and BMP2 or CTGF expression. So far a cause of bone lesions in MM is supposed to be the activity of osteoclast, however, our preliminary examination by TRAP staining revealed that osteoclast differentiation from BMMNC in MM cases by adding M-CSF (25 ng/ml) and RANKL (50 ng/ml) decreased compared with that in normal BM, and osteoblast diffentiation also decreased in MM by cytochemical staining for alkaline phosphatase (AP). We guess that both osteoclast and osteobalst differentiation are suppressed in MM and CTGF is a candidate for the suppressor of osteoblast differentiation. We will be able to show the result of AP activity of osteoblast and the effect of recombinant CTGF on osteoblast in meeting.

C-met Receptor as a Potential Target for the Treatment of Patients with Multiple Myeloma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3395-3395
Author(s):  
Marcin Majka ◽  
Artur Jurczyszyn ◽  
Anna Zebzda ◽  
Wojciech Czogala ◽  
Ewa Lesko ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Cell Lines ◽  
Protein Level ◽  
Bone Marrow Cells ◽  
Response To Therapy ◽  
Poor Responders ◽  
Met Receptor ◽  
Potential Target ◽  
Marrow Cells

Abstract Despite progress in the treatment of Multiple Myeloma (MM), it is still an incurable disease with average survival of 3–4 years. Because MM is often resistant to conventional therapies, new treatment strategies are necessary. The presence of elevated HGF (Hepatocytic Grow Factor) expression has been well documented in multiple myeloma. The c-met oncogene has been shown to be present in MM cell lines at the mRNA and protein level. Some data suggested that this axis could be responsible for proliferation and inhibition of apoptosis in MM cells. In this study we have analyzed c-met expression in 15 patients with (MM) before and after treatment. Seven of these pts responded well and eight pts responded poorly to the employed therapy. All 15 pts were c-met positive before therapy. Bone marrow cellularity of patients who responded well was 76% before (range: 10% – 100%) and 46% after treatment (range: 40% – 60%). In this group plasmocyte infiltration of bone marrow consisted of 59% before (range: 10% – 80%) and 9% after chemotherapy (range: 0% – 20%). Five of them had undetectable c-met positive cells among bone marrow cells after treatment. In the group of poor responders cellularity of bone marrow was 40% (range: 20% – 70%) before treatment and 46% (range: 20% – 70%) after therapy. Plasmocytes consisted of 20% (range: 10% – 50%) of bone marrow cells before and 44% (range: 10% – 90%) after treatment. All patients in this group had cells positive for c-met receptor after therapeutic regiment. This results suggested that c-met-HGF axis might be a good target for alternative therapy in MM. We looked for potential therapeutics that interferes with this axis and we found that geldanamycin (GA) has been shown to decrease expression of c-met at the protein level in several different cell types. Using inhibitors that belongs to geldanamycin family (GA, 17AAG and 17DMAG) we treated MM cell lines and primary sample. We found that these molecules strongly inhibited expression of c-met in both MM cell lines and patients sample as assessed by western blot analysis. We also tested the influence of these inhibitors on proliferation of MM cells. We found that 100nM dose of GA and 17DMAG inhibited growth of MM cell lines by 80% and 100nM dose of 17AAG inhibited growth of these cells by 20%. Primary cells were more resistant to treatment but we still obtained 30% inhibition with GA and 17DMAG. 17AAG was ineffective and proliferation decreased by less than 10%. Grow inhibition was probably not only due to c-met-HGF axis blockade because these molecules also inhibit other proteins (AKT, RAF). In our experiments we have shown that the level of c-met expression correlates with response to therapy. Patients who respond well had substantially decreased number of c-met positive plasmocytes after chemotherapy in comparison to poor responders. We have also showed that drugs that block c-met-HGF axis could be used in treatment of MM. These drugs could potentially inhibit cells proliferation, increase apoptosis and disrupt MM cells interaction with bone marrow environment. Based on these data we postulate that the c-met receptor is a potential target for MM therapy especially in patients who do not respond to the first line of treatment.

Developing In Vivo Model for Studying Mechanisms of Osteoblast Suppression in Multiple Myeloma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4731-4731
Author(s):  
Chang-Sook Hong ◽  
Alisa Huston ◽  
Flavia Esteve ◽  
Judy Anderson ◽  
Ken Patrene ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Osteoblast Differentiation ◽  
Treated Group ◽  
Bone Lesions ◽  
Neoplastic Disease ◽  
In Vivo Models ◽  
Myeloma Cells ◽  
Ganciclovir Treatment

Abstract Multiple myeloma (MM) is an incurable neoplastic disease characterized by an accumulation of plasma cells in bone marrow. Osteolytic bone lesions are the major source of morbidity in MM patients and are associated with bone pain and fractures and hypercalcemia. The bone lesions result from increased osteoclastic bone destruction in areas adjacent to the myeloma cells. New bone formation that normally happens at sites of previous bone resorption still occurs in early stages of the disease but is absent in advanced MM. Although the molecular basis for the increased osteoclastic activity has been intensely investigated, the basis for the decreased osteoblast activity is just beginning to be understood. Recently, inhibitors of WNT signaling pathway, Dickkorpf1 (DKK1) and secreted Frizzle-Related Protein-2 (sFRP2) have been identified as factors involved in osteoblast suppression in MM. In addition, IL-3 and IL-7 are increased in plasma of MM patients and suppress osteoblastogenesis in cell culture models. However, the role of those factors in the osteoblastic activity in MM patients is unclear. Studies in patients are confounded by cytotoxic therapy as well as bisphosphonates, which are standard therapy for MM patients. Therefore, preclinical in vivo models are required to delineate the mechanisms responsible for the profound osteoblast suppression in MM. We have developed a mouse model of myeloma bone disease in which genetically modified myeloma cells can be selectively ablated without the confounding effects of cytotoxic therapies and allows us to tract the growth of MM cells. The 5TGM1 cell line which is the most common version of murine MM, was stably transfected with the thymidine kinase (TK) gene from herpes simplex virus, which permits eradication of myeloma cells with ganciclovir, as well as GFP and luciferase genes to detect the presence of MM cells. One ug/ml ganciclovir treatment in culture results in 100% death of the transfected 5TGM1 cells in 4 days. Importantly, ganciclovir treatment of primary marrow cell cultures had no effect on growth and differentiation of osteoblast and hematopoietic progentitors. Co-culturing of primary marrow cells with 5TGM1 expressing TK has no bystander effect on osteoblast differentiation with ganciclovir treatment. Subcutaneously implanted 5TGM1 cells into SCID mice were eradicated by intraperitoneal injection of 20mg/kg ganciclovir/d for 2 weeks. The dose of ganciclovir did not affect osteoblast differentiation of primary marrow culture from the mice treated with ganciclovir. Then we injected the 5TGM1 cells into tibia of SCID nude mice (n=4 per group). After measuring the increase of serum IgG2b level, half of the mice were treated with ganciclovir for 2 weeks and the other with saline. Our preliminary data show that osteogenic cultures of bone marrow from the ganciclovir treated mice had significantly higher alkaline phosphatase activity than cultures derived from the saline treated group (p=0.03). In addition, the ganciclovir treated mice had tendency of higher trabecular bone volume than the saline-treated group (p=0.08). These results demonstrate that this model should be useful for studying mechanisms of osteoblast suppression in MM.

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