Modeling the human 8p11-myeloproliferative syndrome in immunodeficient mice

Blood ◽  
2010 ◽  
Vol 116 (12) ◽  
pp. 2103-2111 ◽  
Author(s):  
Helena Ågerstam ◽  
Marcus Järås ◽  
Anna Andersson ◽  
Petra Johnels ◽  
Nils Hansen ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Leukemia ◽  
Tyrosine Kinases ◽  
Cellular Proliferation ◽  
Myeloid Cell ◽  
Myeloproliferative Disorder ◽  
Immunodeficient Mice ◽  
Myeloproliferative Syndrome

Abstract The 8p11 myeloproliferative syndrome (EMS), also referred to as stem cell leukemia/lymphoma, is a chronic myeloproliferative disorder that rapidly progresses into acute leukemia. Molecularly, EMS is characterized by fusion of various partner genes to the FGFR1 gene, resulting in constitutive activation of the tyrosine kinases in FGFR1. To date, no previous study has addressed the functional consequences of ectopic FGFR1 expression in the potentially most relevant cellular context, that of normal primary human hematopoietic cells. Herein, we report that expression of ZMYM2/FGFR1 (previously known as ZNF198/FGFR1) or BCR/FGFR1 in normal human CD34+ cells from umbilical-cord blood leads to increased cellular proliferation and differentiation toward the erythroid lineage in vitro. In immunodeficient mice, expression of ZMYM2/FGFR1 or BCR/FGFR1 in human cells induces several features of human EMS, including expansion of several myeloid cell lineages and accumulation of blasts in bone marrow. Moreover, bone marrow fibrosis together with increased extramedullary hematopoiesis is observed. This study suggests that FGFR1 fusion oncogenes, by themselves, are capable of initiating an EMS-like disorder, and provides the first humanized model of a myeloproliferative disorder transforming into acute leukemia in mice. The established in vivo EMS model should provide a valuable tool for future studies of this disorder.

scholarly journals Transcription factor Gfi-1 induced by G-CSF is a negative regulator of CXCR4 in myeloid cells

Blood ◽  
2007 ◽  
Vol 110 (7) ◽  
pp. 2276-2285 ◽  
Author(s):  
Maria De La Luz Sierra ◽  
Paola Gasperini ◽  
Peter J. McCormick ◽  
Jinfang Zhu ◽  
Giovanna Tosato
Keyword(s):  
Bone Marrow ◽  
Dna Sequences ◽  
Peripheral Blood ◽  
Cell Function ◽  
Myeloid Cell ◽  
Cxcr4 Expression ◽  
Negative Regulator ◽  
Hematopoietic Stem

The mechanisms underlying granulocyte-colony stimulating factor (G-CSF)–induced mobilization of granulocytic lineage cells from the bone marrow to the peripheral blood remain elusive. We provide evidence that the transcriptional repressor growth factor independence-1 (Gfi-1) is involved in G-CSF–induced mobilization of granulocytic lineage cells from the bone marrow to the peripheral blood. We show that in vitro and in vivo G-CSF promotes expression of Gfi-1 and down-regulates expression of CXCR4, a chemokine receptor essential for the retention of hematopoietic stem cells and granulocytic cells in the bone marrow. Gfi-1 binds to DNA sequences upstream of the CXCR4 gene and represses CXCR4 expression in myeloid lineage cells. As a consequence, myeloid cell responses to the CXCR4 unique ligand SDF-1 are reduced. Thus, Gfi-1 not only regulates hematopoietic stem cell function and myeloid cell development but also probably promotes the release of granulocytic lineage cells from the bone marrow to the peripheral blood by reducing CXCR4 expression and function.

scholarly journals Thrombopoietin, but not erythropoietin promotes viability and inhibits apoptosis of multipotent murine hematopoietic progenitor cells in vitro

Blood ◽  
1996 ◽  
Vol 88 (8) ◽  
pp. 2859-2870 ◽  
Author(s):  
OJ Borge ◽  
V Ramsfjell ◽  
OP Veiby ◽  
MJ Jr Murphy ◽  
S Lok ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Bone Marrow Cells ◽  
Interleukin 1 ◽  
Calf Serum ◽  
Myeloid Cell ◽  
Promoting Effect ◽  
Multipotent Progenitors

The recently cloned c-mpl ligand, thrombopoietin (Tpo), has been extensively characterized with regard to its ability to stimulate the growth, development, and ploidy of megakaryocyte progenitor cells and platelet production in vitro and in vivo. Primitive hematopoietic progenitors have been shown to express c-mpl, the receptor for Tpo. In the present study, we show that Tpo efficiently promotes the viability of a subpopulation of Lin-Sca-1+ bone marrow progenitor cells. The ability of Tpo to maintain viable Lin-Sca-1+ progenitors was comparable to that of granulocyte colony-stimulating factor and interleukin-1, whereas stem cell factor (SCF) promoted the viability of a higher number of Lin-Sca-1+ progenitor cells when incubated for 40 hours. However, after prolonged (> 40 hours) preincubation, the viability-promoting effect of Tpo was similar to that of SCF. An increased number of progenitors surviving in response to Tpo had megakaryocyte potential (37%), although almost all of the progenitors produced other myeloid cell lineages as well, suggesting that Tpo acts to promote the viability of multipotent progenitors. The ability of Tpo to promote viability of Lin-Sca-1+ progenitor cells was observed when cells were plated at a concentration of 1 cell per well in fetal calf serum-supplemented and serum-depleted medium. Finally, the DNA strand breakage elongation assay showed that Tpo inhibits apoptosis of Lin-Sca-1+ bone marrow cells. Thus, Tpo has a potent ability to promote the viability and suppress apoptosis of primitive multipotent progenitor cells.

GABP Transcription Factor Is Required for Myeloid Cell Development In Vivo.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 374-374 ◽  
Author(s):  
Zhong-fa Yang ◽  
Karen Drumea ◽  
Alan G. Rosmarin
Keyword(s):  
Bone Marrow ◽  
Transcription Factor ◽  
T Cell ◽  
Myeloid Cells ◽  
Myeloid Cell ◽  
Cell Development ◽  
Wild Type ◽  
Ets Domain

Abstract GABP is an ets transcription factor that regulates genes that are required for innate immunity, including CD18 (β2 leukocyte integrin), lysozyme, and neutrophil elastase. GABP consists of two distinct and unrelated proteins. GABPα binds to DNA through its ets domain and recruits GABPβ, which contains the transactivation domain; together, they form a functional tetrameric transcription factor complex. We recently showed that GABP is required for entry into S phase of the cell cycle through its regulation of genes that are required for DNA synthesis and cyclin dependent kinase inhibitors (Yang, et al. Nature Cell Biol9:339, 2007). Furthermore, GABP is an essential component of a retinoic acid responsive myeloid enhanceosome (Resendes and Rosmarin Mol Cell Biol26:3060, 2006). We cloned Gabpa (the gene that encodes mouse Gabpα) from a mouse genomic BAC library and prepared a targeting vector in which the ets domain is flanked by loxP recombination sites (floxed allele). Deletion of both floxed Gabpa alleles causes an early embryonic lethal defect. In order to define the role of Gabpα in myelopoiesis, we bred floxed Gabpa mice to mice that bear the Mx1-Cre transgene, which drives expression of Cre recombinase in response to injection of the synthetic polynucleotide, poly I-C. Deletion of Gabpa dramatically reduced granulocytes and monocytes in the peripheral blood, spleen, and bone marrow, but myeloid cells recovered within weeks. In vitro colony forming assays indicated that myeloid cells in these mice were derived only from Gabpa replete myeloid precursors (that failed to delete both Gabpa alleles), suggesting strong pressure to retain Gabpα in vivo. We used a novel competitive bone marrow transplantation approach to determine if Gabp is required for myeloid cell development in vivo. Sub-lethally irradiated wild-type recipient mice bearing leukocyte marker CD45.1 received equal proportions of bone marrow from wild type CD45.1 donor mice and floxed-Mx1-Cre donor mice that bear CD45.2. Both the CD45.2 (floxed-Mx1-Cre) and CD45.1 (wild type) bone marrow engrafted well. Mice were then injected with pI-pC to induce Cre-mediated deletion of floxed Gabpa. The mature myeloid and T cell compartments were derived almost entirely from wild type CD45.1 cells. This indicates that the proliferation and/or differentiation of myeloid and T cell lineages requires Gabp. In contrast, B cell development was not impaired. We conclude that Gabpa disruption causes a striking loss of myeloid cells in vivo and corroborates prior in vitro data that GABP plays a crucial role in proliferation of myeloid progenitor cells.

Angptl-4 Is Upregulated Under Inflammatory Conditions In The BM Of Mice, Expands Myeloid Progenitors and Accelerates Reconstitution Of Platelets After Myelosuppressive Therapy

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3677-3677
Author(s):  
Anne Schumacher ◽  
Till Braunschweig ◽  
Bernd Denecke ◽  
Tim H. Brümmendorf ◽  
Patrick Ziegler
Keyword(s):  
Bone Marrow ◽  
Conflicts Of Interest ◽  
Myeloid Cell ◽  
Relative Increase ◽  
T Test ◽  
Gm Csf ◽  
Emergency Situations ◽  
Inflammatory Conditions

Abstract The concerted action of hematopoiesis supporting cytokines such as G-CSF, GM-CSF or IL-6 regulates hematopoiesis during steady state and emergency situations. Respective knockout mice show defects both in production and function of myelopoietic effector cells. However, alternative pathways are likely to exist as mice with single or combined deficiencies for G-CSF, GM-CSF, and IL-6 or G-CSF and GM-CSF are still able to mount reactive neutrophilia responses during inflammatory conditions. In order to identify pathways for inflammation induced enhancement of hematopoiesis as well as to find new cytokines, which enhance myeloid cell regeneration, we analyzed the bone marrow (BM) of lipopolysaccharide (LPS) and vehicle injected wild type (WT) mice (single IP- injection) by gene expression microarray. Focusing on the identification of genes encoding for secreted or membrane proteins, we found 83 candidates to be up- and 14 to be downregulated after LPS treatment. Among known candiates, we found angiopoietin-like 4 (Angptl-4) as a predominantly upregulated gene in the BM of LPS-treated WT-mice. Upregulation was confirmed by RT-PCR as well as by Elisa in the BM of LPS treated mice and bone marrow stromal cells (BMSC) were identified as candidate producer cells. Functionally, we found recombinant Angptl-4 to stimulate the proliferation of myeloid colony-forming units (CFU) in vitro. In mice, repeated injections of Angptl-4 increased BM progenitor cell frequency and this was paralleled by a relative increase in phenotypically defined granulocyte-macrophage progenitors (GMPs). Furthermore, in vivo treatment with Angptl-4 resulted in elevated platelet counts both in untreated animals and after myelosuppressive therapy. After lethal irradiation and transplantation of syngeneic BM cells repetitive injections of recombinant Angptl-4 for 5 consecutive days resulted in an accelerated reconstitution of platelets starting at day 8 after transplantation. The 50% pre-treatment platelet count was reached on day 14 in Angptl-4-treated animals as compared to day 21 for transplanted controls receiving no Angptl-4 (n=8; p=0.03, student´s T test). In contrast, transplantation of BM cells from Angptl-4 pre-treated donor mice had no effect on the recovery of platelets in this setting. The frequency of CD41lowCD61+ immature megakaryocytes was significantly increased in the BM of Angptl-4 injected as compared to control mice (27% vs 19% of total megakaryocytes; p= 0.008, student´s T test). Furthermore, bone marrow cytology revealed local accumulation of megakaryocytes carrying dysplastic features in Angptl-4 injected mice. In summary, our data suggest that Angptl-4 plays a complementary role on hematopoiesis during emergency situations like sepsis. The use of Angptl-4 in the setting of autologous stem cell transplantation could represent a potential approach to accelerate the reconstitution of megakaryopoiesis. Disclosures: No relevant conflicts of interest to declare.

Evidence for Vasculogenic Potential and Endothelial Differentiation of Bone-Marrow-Derived Very Small Embryonic-like Stem Cells

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5120-5120
Author(s):  
Coralie L Guerin ◽  
Xavier Loyer ◽  
Jose Vilar ◽  
Audrey Cras ◽  
Tristan Mirault ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Conflicts Of Interest ◽  
Tissue Injury ◽  
Multipotent Stem Cells ◽  
Angiogenic Potential ◽  
Immunodeficient Mice ◽  
Positive Expression

Abstract Objective: Very small embryonic-like stem cells (VSELs) are multipotent stem cells localized in adult bone marrow (BM) that may be mobilized into peripheral blood (PB) in response to tissue injury. We aimed to quantify VSELs in BM and PB of patients with critical limb ischemia (CLI) and to test their angiogenic potential in vitro as well as their therapeutic capacity in mouse model of CLI. Approach and Results: We isolated BM VSELs from patients with CLI and studied their potential to differentiate into vascular lineages. Flow and imaging cytometry showed that VSEL counts were lower in BM (p<0.001) and higher (p<0.001) in PB from CLI patients compared to healthy controls, suggesting that ischemia may trigger VSELs mobilization in this patient population. Sorted BM-VSELs cultured in angiogenic media acquired a mesenchymal phenotype (CD90+, Thy-1 gene positive expression). VSEL-derived cells had a pattern of secretion similar to that of endothelial progenitor cells, as they released low levels of VEGF-A and inflammatory cytokines. Noteworthy, VSELs triggered post-ischemic revascularization in immunodeficient mice (p<0.05 vs PBS treatment), and acquired an endothelial phenotype either in vitro when cultured in the presence of VEGF-B (Cdh-5 gene positive expression), or in vivo in Matrigel implants (human CD31+ staining in neo-vessels from plug sections). Conclusions: VSELs are a potential new source of therapeutic cells that may give rise to cells of the endothelial lineage in humans. Disclosures No relevant conflicts of interest to declare.

Bone-marrow-derived very small embryonic-like stem cells in patients with critical leg ischaemia: evidence of vasculogenic potential

2015 ◽  
Vol 113 (05) ◽  
pp. 1084-1094 ◽  
Author(s):  
Coralie L. Guerin ◽  
Xavier Loyer ◽  
José Vilar ◽  
Audrey Cras ◽  
Tristan Mirault ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Tissue Injury ◽  
Critical Limb Ischaemia ◽  
Limb Ischaemia ◽  
Multipotent Stem Cells ◽  
Immunodeficient Mice ◽  
Positive Expression

SummaryVery small embryonic-like stem cells (VSELs) are multipotent stem cells localised in adult bone marrow (BM) that may be mobilised into peripheral blood (PB) in response to tissue injury. We aimed to quantify VSELs in BM and PB of patients with critical limb ischaemia (CLI) and to test their angiogenic potential in vitro as well as their therapeutic capacity in mouse model of CLI. We isolated BM VSELs from patients with CLI and studied their potential to differentiate into vascular lineages. Flow and imaging cytometry showed that VSEL counts were lower in BM (p< 0.001) and higher (p< 0.001) in PB from CLI patients compared to healthy controls, suggesting that ischaemia may trigger VSELs mobilisation in this patient population. Sorted BM-VSELs cultured in angiogenic media acquired a mesenchymal phenotype (CD90+, Thy-1 gene positive expression). VSEL-derived cells had a pattern of secretion similar to that of endothelial progenitor cells, as they released low levels of VEGF-A and inflammatory cytokines. Noteworthy, VSELs triggered post-ischaemic revascularisation in immunodeficient mice (p< 0.05 vs PBS treatment), and acquired an endothelial phenotype either in vitro when cultured in the presence of VEGF-B (Cdh-5 gene positive expression), or in vivo in Matrigel implants (human CD31+ staining in neo-vessels from plug sections). In conclusion, VSELs are a potential new source of therapeutic cells that may give rise to cells of the endothelial lineage in humans.

Proteasome inhibitor bortezomib impairs both myelofibrosis and osteosclerosis induced by high thrombopoietin levels in mice

Blood ◽  
2007 ◽  
Vol 110 (1) ◽  
pp. 345-353 ◽  
Author(s):  
Orianne Wagner-Ballon ◽  
Didier F. Pisani ◽  
Thomas Gastinne ◽  
Micheline Tulliez ◽  
Ronan Chaligné ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Drug Therapy ◽  
Murine Model ◽  
Proteasome Inhibitor ◽  
Primary Myelofibrosis ◽  
Myeloproliferative Disorder ◽  
Stromal Reaction ◽  
Tgf Β1

Primary myelofibrosis (PMF) is the most serious myeloproliferative disorder, characterized by clonal myeloproliferation associated with cytokine-mediated bone marrow stromal reaction including fibrosis and osteosclerosis. Current drug therapy remains mainly palliative. Because the NF-κB pathway is implicated in the abnormal release of cytokines in PMF, the proteasome inhibitor bortezomib might be a potential therapy. To test its effect, we used the lethal murine model of myelofibrosis induced by thrombopoietin (TPO) overexpression. In this TPOhigh model, the development of the disease is related to a deregulated MPL signaling, as recently described in PMF patients. We first demonstrated that bortezomib was able to inhibit TPO-induced NF-κB activation in vitro in murine megakaryocytes. It also inhibited NF-κB activation in vivo in TPOhigh mice leading to decreased IL-1α plasma levels. After 4 weeks of treatment, bortezomib decreased TGF-β1 levels in marrow fluids and impaired marrow and spleen fibrosis development. After 12 weeks of treatment, bortezomib also impaired osteosclerosis development through osteoprotegerin inhibition. Moreover, this drug reduced myeloproliferation induced by high TPO level. Finally, bortezomib dramatically improved TPOhigh mouse survival (89% vs 8% at week 52). We conclude that bortezomib appears as a promising therapy for future treatment of PMF patients.

Oncogenic interaction between BCR-ABL andNUP98-HOXA9 demonstrated by the use of an in vitro purging culture system

Blood ◽  
2002 ◽  
Vol 100 (12) ◽  
pp. 4177-4184 ◽  
Author(s):  
Nadine Mayotte ◽  
Denis-Claude Roy ◽  
Jing Yao ◽  
Evert Kroon ◽  
Guy Sauvageau
Keyword(s):  
Bone Marrow ◽  
Acute Leukemia ◽  
Disease Progression ◽  
Bone Marrow Cells ◽  
Myelogenous Leukemia ◽  
Mouse Bone Marrow ◽  
Genetic Level ◽  
Marrow Cells

Chronic myelogenous leukemia (CML) is a clonal stem cell disease caused by the BCR-ABL oncoprotein and is characterized, in its early phase, by excessive accumulation of mature myeloid cells, which eventually leads to acute leukemia. The genetic events involved in CML's progression to acute leukemia remain largely unknown. Recent studies have detected the presence of theNUP98-HOXA9 fusion oncogene in acute leukemia derived from CML patients, which suggests that these 2 oncoproteins may interact and influence CML disease progression. Using in vitro purging of BCR-ABL–transduced mouse bone marrow cells, we can now report that recipients of bone marrow cells engineered to coexpressBCR-ABL with NUP98-HOXA9 develop acute leukemia within 7 to 10 days after transplantation. However, no disease is detected for more than 2 months in mice receiving bone marrow cells expressing either BCR-ABL orNUP98-HOXA9. We also provide evidence of high levels ofHOXA9 expressed in leukemic blasts from acute-phase CML patients and that it interacts significantly on a genetic level withBCR-ABL in our in vivo CML model. Together, these studies support a causative, as opposed to a consequential, role forNUP98-HOXA9 (and possibly HOXA9) in CML disease progression.

Interferon Regulatory Factor 4 Is Not Required for Induction of Chronic Myeloid Leukaemia-Like Myeloproliferative Disease by Bcr/Abl in Mice.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2866-2866
Author(s):  
Anna Lena Illert ◽  
Cornelius Miething ◽  
Rebekka Grundler ◽  
Manuel Schmidt ◽  
Andreas Burchert ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Plasma Cells ◽  
Pulmonary Haemorrhage ◽  
Myeloproliferative Disorder ◽  
Control Group ◽  
Type I ◽  
Myeloproliferative Disease

Abstract Interferon regulatory factors (IRF) are activating and/or repressing transcription factors induced by treatment with type I and II Interferon (IFN), other cytokines, receptor cross-linking and viral infection. In contrast to IRF-1 and IRF-2, which are widely expressed, IRF-4 and IRF-8 are tissue-restricted factors. IRF-8 is expressed mainly in cells of haematopoietic origin and has recently been shown to inhibit mitogenic activity of p210 Bcr/Abl-transformed myeloid progenitor cells by activating several genes that interfere with the c-Myc pathway. IRF-4 is most homologous with IRF-8 (approximately 70% overall homology) and its expression is highly restricted to lymphocytes of the B-cell type (pre-B, B, and plasma cells), mature T-cells and macrophages. Furthermore IRF-4 expression is significantly impaired in CML and AML patient samples predominately in T-cells. To examine a potential role of IRF-4 in Bcr/Abl mediated transformation we used a bone marrow transplant model (BMT). We transduced IRF-4 knockout (KO) bone marrow with retrovirus expressing p210 Bcr/Abl and transplanted it into lethally irradiated recipient C57/bl6 mice. For proper control we transplanted also wildtype (WT) bone marrow transduced with Bcr/Abl and mock transfected IRF-4 KO bone marrow (BM). All recipients transplanted with Bcr/Abl transduced BM (regardless of which IRF-4 KO or WT) developed rapidly a myeloproliferative disorder characterized by leukocytosis and expression of the myeloid lineage markers CD11b and Gr1. Surprisingly, IRF-4 KO Bcr/Abl infected BM recipient mice survived slightly longer than the control group transplanted with WT p210 BM (12 vs. 19 days). Histopathologic studies of the affected organs (spleen/lung) revealed extramedullary haematopoiesis in the spleens of both groups and a distinct infiltration of the tumor cells in the lung of WT Bcr/Abl transduced BM recipient mice, resulting in massive punctuated bleedings. Interestingly, preliminary analysis suggest a significantly reduced lung infiltration with almost no pulmonary bleedings in IRF-4 KO Bcr/Abl infected BM recipient mice, which we assume to be the reason for the differences in the overall survival. Taken together our data demonstrate that IRF-4 is not required for the induction of a myeloproliferative disorder by Bcr/Abl in vivo and for its ability to transform BM cells in vitro, but IRF-4 deficiency seems to have an impact on the fulminant pulmonary haemorrhage occurring in the murine CML-like disease.

CHIR-258 Efficacy in a Newly Developed Preclinical Bone Marrow Model of t(4;14) Multiple Myeloma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3449-3449
Author(s):  
Xiaohua Xin ◽  
Yan Tang ◽  
Yoko Oei ◽  
Helen Ye ◽  
Daniel Menezes ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Tyrosine Kinases ◽  
Ectopic Expression ◽  
Chromosomal Translocation ◽  
Significant Inhibition ◽  
In Vivo Model ◽  
Class Iii

Abstract Multiple myeloma (MM) remains a fatal hematological malignancy due to the development of drug resistance to conventional high-dosage chemotherapy. It has been demonstrated that the bone marrow microenvironment, where MM cells preferentially home and grow, plays a crucial role in developing resistance to therapies for MM. Recent understanding of the molecular pathology of MM has provided novel therapeutic targets for treatment of this disease. The ectopic expression of FGFR3, which occurs in approximately 15–20% MM patients resulting from a t(4;14) chromosomal translocation and confers a particularly poor prognosis in clinic, has become an attractive therapeutic target for MM. CHIR-258 is a small molecule inhibitor of Class III, IV and V receptor tyrosine kinases, including FGFR, VEGFR and PDGFR (IC50s ~5–15 nM in kinase assays). It has been demonstrated that CHIR-258 inhibits FGFR3 autophosphorylation, downstream signaling and cell proliferation in FGFR3 mutant MM cells in vitro as well as induces apoptosis in FGFR3 positive primary myeloma cells (Trudel, et.al, Blood 2005). To evaluate the anti-myeloma efficacy of CHIR-258, we developed an in vivo MM model in which multi-organ MM lesions developed after tail vein injection of human KMS-11-luc cells stably transfected with luciferase. This cell line harbors the t(4;14) translocation and expresses constitutively active FGFR3 (Y373C mutation). Non-invasive bioluminescent imaging (BLI) was used to monitor the in vivo growth and dissemination of KMS-11-luc MM tumors. Early detection and serial imaging monitoring the growth of metastatic lesions was successfully captured by BLI in this model. Nearly all mice injected with KMS-11-luc tumor cells were found to develop MM lesions, which were mainly localized in spine, skull and pelvis. We examined CHIR-258 anti-myeloma efficacy in this model and found that daily oral administration of CHIR-258 at 20 mg/kg, a dose that was demonstrated to inhibit phosphorylation of ERK in KMS-11-luc tumors in vivo, resulted in a significant inhibition of tumor growth. Furthermore, this anti-tumor activity of CHIR-258 translated to a significant improvement of animal survival compared to vehicle treatment in this model. In vitro combination studies with dexamethasone and bortezomib in KMS-11 cells demonstrated synergistic and additive effects, respectively. The development of this KMS-11-luc in vivo model will allow further evaluation of CHIR-258 combination therapy with conventional or other molecularly targeted agents. These studies have provided further rationale for the ongoing clinical trials of CHIR-258 in MM.

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