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Acute progression of BCR-FGFR1 induced murine B-lympho/myeloproliferative disorder suggests involvement of lineages at the pro-B cell stage.

Ren M, Tidwell JA, Sharma S, Cowell JK - PLoS ONE (2012)

Bottom Line: Constitutive activation of FGFR1, through rearrangement with various dimerization domains, leads to atypical myeloproliferative disorders where, although T cell lymphoma are common, the BCR-FGFR1 chimeric kinase results in CML-like leukemia.The B220(-) phenotype was retained in one of the cell lines while the other was B220(+).When the two cell lines were transplanted into syngeneic mice, all animals developed the same B-lymphoblastic leukemia within 2-weeks.

View Article: PubMed Central - PubMed

Affiliation: Georgia Health Sciences University Cancer Center, Georgia Health Sciences University School of Medicine, Augusta, Georgia, United States of America.

ABSTRACT
Constitutive activation of FGFR1, through rearrangement with various dimerization domains, leads to atypical myeloproliferative disorders where, although T cell lymphoma are common, the BCR-FGFR1 chimeric kinase results in CML-like leukemia. As with the human disease, mouse bone marrow transduction/transplantation with BCR-FGFR1 leads to CML-like myeloproliferation as well as B-cell leukemia/lymphoma. The murine disease described in this report is virtually identical to the human disease in that both showed bi-lineage involvement of myeloid and B-cells, splenomegaly, leukocytosis and bone marrow hypercellularity. A CD19(+) IgM(-) CD43(+) immunophenotype was seen both in primary tumors and two cell lines derived from these tumors. In all primary tumors, subpopulations of these CD19(+) IgM(-) CD43(+) were also either B220(+) or B220(-), suggesting a block in differentiation at the pro-B cell stage. The B220(-) phenotype was retained in one of the cell lines while the other was B220(+). When the two cell lines were transplanted into syngeneic mice, all animals developed the same B-lymphoblastic leukemia within 2-weeks. Thus, the murine model described here closely mimics the human disease with bilineage myeloid and B-cell leukemia/lymphoma which provides a representative model to investigate therapeutic intervention and a better understanding of the etiology of the disease.

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BCR-FGFR1 simultaneously induces B-cell leukemia/lymphoma and myeloid proliferative disorder.Representative flow cytometric analysis of bone marrow (A), spleen (B) and peripheral blood (C) cells from primary transplanted mouse #5 with BCR-FGFR1-induced disease shows that the majority of B-cells are arrested at pro-B stage with a CD19+IgM− immunophenotype in both GFP positive and negative cells. The presence of GFP+Mac-1+Gr-1+ populations, as well as high levels of GFP−Mac-1+Gr-1+ cells, was also seen. Very few T-lineage (CD4+ and/or CD8+) cells were present in the leukemic spleen. GFP expression was lost in the peripheral blood from the majority of primary recipients, where the BCR-FGFR1 fusion transcript can be detected by RT-PCR (C, below). D) Most of the primary transplanted mice showed enlarged lymph nodes and/or tumors in their abdomens. Representative flow cytometric analysis of the tumor cells shows the predominantly pro-B lymphoma immunophenotype, CD19+IgM−. E) Schematic diagram showing the progression of B-cell development from hematopoietic stem cells (HSC) and common lymphoid progenitors (CLP) into mature B cells and plasma cells. The immunophenotype of the B-lineage cells carrying the BCR-FGFR1 fusion kinase suggests an arrest at the pro-B stage of development as indicated.
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pone-0038265-g002: BCR-FGFR1 simultaneously induces B-cell leukemia/lymphoma and myeloid proliferative disorder.Representative flow cytometric analysis of bone marrow (A), spleen (B) and peripheral blood (C) cells from primary transplanted mouse #5 with BCR-FGFR1-induced disease shows that the majority of B-cells are arrested at pro-B stage with a CD19+IgM− immunophenotype in both GFP positive and negative cells. The presence of GFP+Mac-1+Gr-1+ populations, as well as high levels of GFP−Mac-1+Gr-1+ cells, was also seen. Very few T-lineage (CD4+ and/or CD8+) cells were present in the leukemic spleen. GFP expression was lost in the peripheral blood from the majority of primary recipients, where the BCR-FGFR1 fusion transcript can be detected by RT-PCR (C, below). D) Most of the primary transplanted mice showed enlarged lymph nodes and/or tumors in their abdomens. Representative flow cytometric analysis of the tumor cells shows the predominantly pro-B lymphoma immunophenotype, CD19+IgM−. E) Schematic diagram showing the progression of B-cell development from hematopoietic stem cells (HSC) and common lymphoid progenitors (CLP) into mature B cells and plasma cells. The immunophenotype of the B-lineage cells carrying the BCR-FGFR1 fusion kinase suggests an arrest at the pro-B stage of development as indicated.

Mentions: Expression of EGFP in the BCR-FGFR1 transformed leukemic cells conveniently permitted flow cytometric analysis of cells carrying the fusion kinase. Premature death of one founder mouse precluded conclusive flow analysis in this case, but the remaining 8 were used in subsequent analyses. Flow cytometric analysis using lineage-specific markers was performed in all the available primary recipients. An analysis of GFP+ splenocytes using B cell markers identified populations that were IgM−CD19+CD43+B220+ (Figure 2A). GFP+ myeloid cells in the spleen showed co-expression of Mac-1 and Gr-1 (Figure 2A) and, in all but one mouse, were found at lower frequencies than the GFP+ B cells. As an exception, the majority of GFP+ cells in mouse #1 and #2 were Mac-1+Gr-1+ (Figure S1A) suggesting a predominantly myeloid disease. Since early B-cell development is mainly located in the bone marrow, we also analysed the bone marrow compared with the peripheral blood cells from all the disease mice, which showed a similar phenotype (Figure 2B and C). During this analysis, we noticed that peripheral blood from several primary recipients had lost GFP expression, even though bone marrow cells in these animals contained GFP+ cells, and RT-PCR analysis demonstrated that these GFP− cells carried the BCR-FGFR1 fusion gene (Figure 2C). In all the primary recipients, very few (1%) splenocytes showed a GFP+CD4+CD8+ phenotype excluding the possibility of T-cell disease. Most of the primary transplanted mice showed enlarged lymph nodes and/or tumors in their abdomens. These tumor cells were GFP+ IgM− CD19+CD43+ (Figure 2D) which is consistent with a pro-B cell phenotype (Figure 2D). During these analyses we noticed that the GFP+ cells only accounted for <20% of whole cell population, suggesting that most tumor cells had lost GFP expression. Consistent with this suggestion, the majority of GFP negative cells shared the same abnormal immunophenotype with GFP positive cells, i.e. IgM−CD19+CD43+ (Figures 2 and S1), Gr1+Mac1+ B220+ or Gr1+Mac1+CD19+ (Figure S1). Furthermore, the BBC1 cell line derived from one primary recipient is GFP negative and expresses the BCR-FGFR1 fusion protein (Figure 2A and 4A). Overall, therefore, BCR-FGFR1 induced both myeloid leukemia and B-cell leukemia/lymphoma blocked at the pro-B stage in most mice and there was no evidence of T-cell disease.


Acute progression of BCR-FGFR1 induced murine B-lympho/myeloproliferative disorder suggests involvement of lineages at the pro-B cell stage.

Ren M, Tidwell JA, Sharma S, Cowell JK - PLoS ONE (2012)

BCR-FGFR1 simultaneously induces B-cell leukemia/lymphoma and myeloid proliferative disorder.Representative flow cytometric analysis of bone marrow (A), spleen (B) and peripheral blood (C) cells from primary transplanted mouse #5 with BCR-FGFR1-induced disease shows that the majority of B-cells are arrested at pro-B stage with a CD19+IgM− immunophenotype in both GFP positive and negative cells. The presence of GFP+Mac-1+Gr-1+ populations, as well as high levels of GFP−Mac-1+Gr-1+ cells, was also seen. Very few T-lineage (CD4+ and/or CD8+) cells were present in the leukemic spleen. GFP expression was lost in the peripheral blood from the majority of primary recipients, where the BCR-FGFR1 fusion transcript can be detected by RT-PCR (C, below). D) Most of the primary transplanted mice showed enlarged lymph nodes and/or tumors in their abdomens. Representative flow cytometric analysis of the tumor cells shows the predominantly pro-B lymphoma immunophenotype, CD19+IgM−. E) Schematic diagram showing the progression of B-cell development from hematopoietic stem cells (HSC) and common lymphoid progenitors (CLP) into mature B cells and plasma cells. The immunophenotype of the B-lineage cells carrying the BCR-FGFR1 fusion kinase suggests an arrest at the pro-B stage of development as indicated.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368885&req=5

pone-0038265-g002: BCR-FGFR1 simultaneously induces B-cell leukemia/lymphoma and myeloid proliferative disorder.Representative flow cytometric analysis of bone marrow (A), spleen (B) and peripheral blood (C) cells from primary transplanted mouse #5 with BCR-FGFR1-induced disease shows that the majority of B-cells are arrested at pro-B stage with a CD19+IgM− immunophenotype in both GFP positive and negative cells. The presence of GFP+Mac-1+Gr-1+ populations, as well as high levels of GFP−Mac-1+Gr-1+ cells, was also seen. Very few T-lineage (CD4+ and/or CD8+) cells were present in the leukemic spleen. GFP expression was lost in the peripheral blood from the majority of primary recipients, where the BCR-FGFR1 fusion transcript can be detected by RT-PCR (C, below). D) Most of the primary transplanted mice showed enlarged lymph nodes and/or tumors in their abdomens. Representative flow cytometric analysis of the tumor cells shows the predominantly pro-B lymphoma immunophenotype, CD19+IgM−. E) Schematic diagram showing the progression of B-cell development from hematopoietic stem cells (HSC) and common lymphoid progenitors (CLP) into mature B cells and plasma cells. The immunophenotype of the B-lineage cells carrying the BCR-FGFR1 fusion kinase suggests an arrest at the pro-B stage of development as indicated.
Mentions: Expression of EGFP in the BCR-FGFR1 transformed leukemic cells conveniently permitted flow cytometric analysis of cells carrying the fusion kinase. Premature death of one founder mouse precluded conclusive flow analysis in this case, but the remaining 8 were used in subsequent analyses. Flow cytometric analysis using lineage-specific markers was performed in all the available primary recipients. An analysis of GFP+ splenocytes using B cell markers identified populations that were IgM−CD19+CD43+B220+ (Figure 2A). GFP+ myeloid cells in the spleen showed co-expression of Mac-1 and Gr-1 (Figure 2A) and, in all but one mouse, were found at lower frequencies than the GFP+ B cells. As an exception, the majority of GFP+ cells in mouse #1 and #2 were Mac-1+Gr-1+ (Figure S1A) suggesting a predominantly myeloid disease. Since early B-cell development is mainly located in the bone marrow, we also analysed the bone marrow compared with the peripheral blood cells from all the disease mice, which showed a similar phenotype (Figure 2B and C). During this analysis, we noticed that peripheral blood from several primary recipients had lost GFP expression, even though bone marrow cells in these animals contained GFP+ cells, and RT-PCR analysis demonstrated that these GFP− cells carried the BCR-FGFR1 fusion gene (Figure 2C). In all the primary recipients, very few (1%) splenocytes showed a GFP+CD4+CD8+ phenotype excluding the possibility of T-cell disease. Most of the primary transplanted mice showed enlarged lymph nodes and/or tumors in their abdomens. These tumor cells were GFP+ IgM− CD19+CD43+ (Figure 2D) which is consistent with a pro-B cell phenotype (Figure 2D). During these analyses we noticed that the GFP+ cells only accounted for <20% of whole cell population, suggesting that most tumor cells had lost GFP expression. Consistent with this suggestion, the majority of GFP negative cells shared the same abnormal immunophenotype with GFP positive cells, i.e. IgM−CD19+CD43+ (Figures 2 and S1), Gr1+Mac1+ B220+ or Gr1+Mac1+CD19+ (Figure S1). Furthermore, the BBC1 cell line derived from one primary recipient is GFP negative and expresses the BCR-FGFR1 fusion protein (Figure 2A and 4A). Overall, therefore, BCR-FGFR1 induced both myeloid leukemia and B-cell leukemia/lymphoma blocked at the pro-B stage in most mice and there was no evidence of T-cell disease.

Bottom Line: Constitutive activation of FGFR1, through rearrangement with various dimerization domains, leads to atypical myeloproliferative disorders where, although T cell lymphoma are common, the BCR-FGFR1 chimeric kinase results in CML-like leukemia.The B220(-) phenotype was retained in one of the cell lines while the other was B220(+).When the two cell lines were transplanted into syngeneic mice, all animals developed the same B-lymphoblastic leukemia within 2-weeks.

View Article: PubMed Central - PubMed

Affiliation: Georgia Health Sciences University Cancer Center, Georgia Health Sciences University School of Medicine, Augusta, Georgia, United States of America.

ABSTRACT
Constitutive activation of FGFR1, through rearrangement with various dimerization domains, leads to atypical myeloproliferative disorders where, although T cell lymphoma are common, the BCR-FGFR1 chimeric kinase results in CML-like leukemia. As with the human disease, mouse bone marrow transduction/transplantation with BCR-FGFR1 leads to CML-like myeloproliferation as well as B-cell leukemia/lymphoma. The murine disease described in this report is virtually identical to the human disease in that both showed bi-lineage involvement of myeloid and B-cells, splenomegaly, leukocytosis and bone marrow hypercellularity. A CD19(+) IgM(-) CD43(+) immunophenotype was seen both in primary tumors and two cell lines derived from these tumors. In all primary tumors, subpopulations of these CD19(+) IgM(-) CD43(+) were also either B220(+) or B220(-), suggesting a block in differentiation at the pro-B cell stage. The B220(-) phenotype was retained in one of the cell lines while the other was B220(+). When the two cell lines were transplanted into syngeneic mice, all animals developed the same B-lymphoblastic leukemia within 2-weeks. Thus, the murine model described here closely mimics the human disease with bilineage myeloid and B-cell leukemia/lymphoma which provides a representative model to investigate therapeutic intervention and a better understanding of the etiology of the disease.

Show MeSH
Related in: MedlinePlus