Project description:Although information on the molecular pathogenesis of Waldenström’s Macroglobulinemia (WM) has greatly improved in recent years, the exact cellular origin and the mechanisms behind WM transformation from IgM MGUS remain undetermined. Here, we undertook an integrative phenotypic, molecular and genomic approach to study clonal B-cells from newly-diagnosed patients with IgM MGUS (n=22), smoldering (n=17), and symptomatic WM (n=10). Through principal-component-analysis of multidimensional flow cytometry data, we demonstrated overlapping phenotypic profiles between clonal B-cells from IgM MGUS, smoldering and symptomatic WM patients. Similarly, virtually no genes were significantly deregulated between FACS-sorted clonal B-cells from the three disease stages. Interestingly, while the transcriptome of the Waldenström’s clone was highly deregulated as compared to CD25-CD22+ normal B-cells, significantly less genes were differentially expressed and specific WM pathways down-regulated while comparing the transcriptome of the Waldenström’s clone vs. its normal phenotypic counterpart: CD25+CD22+dim B-cells. The frequency of specific copy number abnormalities [+4, del(6q23.3-6q25.3), +12, and +18q11-18q23] progressively increased from IgM MGUS and smoldering WM vs. symptomatic WM (18% vs. 20% and 73%, respectively; P =.008), suggesting a multistep transformation of clonal B-cells that albeit benign (i.e.: IgM MGUS and smoldering WM), already harbor the phenotypic and molecular signatures of the malignant Waldenström’s clone. Normal bone marrow CD25+ B-cells, Clonal B-Cells from IgM Monoclonal Gammopathy of Undetermined Significance, and Clonal B-Cells from Waldenström's Macroglobulinemia
Project description:Although information on the molecular pathogenesis of Waldenström’s Macroglobulinemia (WM) has greatly improved in recent years, the exact cellular origin and the mechanisms behind WM transformation from IgM MGUS remain undetermined. Here, we undertook an integrative phenotypic, molecular and genomic approach to study clonal B-cells from newly-diagnosed patients with IgM MGUS (n=22), smoldering (n=17), and symptomatic WM (n=10). Through principal-component-analysis of multidimensional flow cytometry data, we demonstrated overlapping phenotypic profiles between clonal B-cells from IgM MGUS, smoldering and symptomatic WM patients. Similarly, virtually no genes were significantly deregulated between FACS-sorted clonal B-cells from the three disease stages. Interestingly, while the transcriptome of the Waldenström’s clone was highly deregulated as compared to CD25-CD22+ normal B-cells, significantly less genes were differentially expressed and specific WM pathways down-regulated while comparing the transcriptome of the Waldenström’s clone vs. its normal phenotypic counterpart: CD25+CD22+dim B-cells. The frequency of specific copy number abnormalities [+4, del(6q23.3-6q25.3), +12, and +18q11-18q23] progressively increased from IgM MGUS and smoldering WM vs. symptomatic WM (18% vs. 20% and 73%, respectively; P =.008), suggesting a multistep transformation of clonal B-cells that albeit benign (i.e.: IgM MGUS and smoldering WM), already harbor the phenotypic and molecular signatures of the malignant Waldenström’s clone.
Project description:Although information on the molecular pathogenesis of Waldenström’s Macroglobulinemia (WM) has greatly improved in recent years, the exact cellular origin and the mechanisms behind WM transformation from IgM MGUS remain undetermined. Here, we undertook an integrative phenotypic, molecular and genomic approach to study clonal B-cells from newly-diagnosed patients with IgM MGUS (n=22), smoldering (n=17), and symptomatic WM (n=10). Through principal-component-analysis of multidimensional flow cytometry data, we demonstrated overlapping phenotypic profiles between clonal B-cells from IgM MGUS, smoldering and symptomatic WM patients. Similarly, virtually no genes were significantly deregulated between FACS-sorted clonal B-cells from the three disease stages. Interestingly, while the transcriptome of the Waldenström’s clone was highly deregulated as compared to CD25-CD22+ normal B-cells, significantly less genes were differentially expressed and specific WM pathways down-regulated while comparing the transcriptome of the Waldenström’s clone vs. its normal phenotypic counterpart: CD25+CD22+dim B-cells. The frequency of specific copy number abnormalities [+4, del(6q23.3-6q25.3), +12, and +18q11-18q23] progressively increased from IgM MGUS and smoldering WM vs. symptomatic WM (18% vs. 20% and 73%, respectively; P =.008), suggesting a multistep transformation of clonal B-cells that albeit benign (i.e.: IgM MGUS and smoldering WM), already harbor the phenotypic and molecular signatures of the malignant Waldenström’s clone. Copy number analysis using the Affymetrix CytoScan 750K Array to study clonal B-cells from newly-diagnosed patients with IgM MGUS, smoldering, and symptomatic WM. Peripheral T-cells from paired and unpaired controls were also assessed.
Project description:Classification of human liver cancer into biologically distinct subgroups suggests origin from different hepatic lineage cells. To clarify contribution of lineage stage in liver oncogenesis, we transduced H-Ras and SV40LT into hepatic progenitor cells (HPC), hepatoblasts (HB) and terminally differentiated adult hepatocytes (AH). Regardless of origin, all transformed cell types acquired common cancer stem cell characteristics in vitro and in vivo. However, expression analysis distinguished tumors of different cellular origin underscoring the contribution of lineage/stage-dependent genetic changes in malignant transformation. Notably, AH-derived tumors showed specific enrichment of c-Myc target genes. These data establish that any hepatic lineage cell can be a target for transformation and acquire common cancer stem cell traits via activation of diverse cell type specific pathways. Profiling of individual tumors derived by Ras/SV40 transformation of hepatic progenitor cell (oval cells), hepatoblasts (fetal) and adult hepatocytes
Project description:Although information on the molecular pathogenesis of Waldenström’s Macroglobulinemia (WM) has greatly improved in recent years, the exact cellular origin and the mechanisms behind WM transformation from IgM MGUS remain undetermined. Here, we undertook an integrative phenotypic, molecular and genomic approach to study clonal B-cells from newly-diagnosed patients with IgM MGUS (n=22), smoldering (n=17), and symptomatic WM (n=10). Through principal-component-analysis of multidimensional flow cytometry data, we demonstrated overlapping phenotypic profiles between clonal B-cells from IgM MGUS, smoldering and symptomatic WM patients. Similarly, virtually no genes were significantly deregulated between FACS-sorted clonal B-cells from the three disease stages. Interestingly, while the transcriptome of the Waldenström’s clone was highly deregulated as compared to CD25-CD22+ normal B-cells, significantly less genes were differentially expressed and specific WM pathways down-regulated while comparing the transcriptome of the Waldenström’s clone vs. its normal phenotypic counterpart: CD25+CD22+dim B-cells. The frequency of specific copy number abnormalities [+4, del(6q23.3-6q25.3), +12, and +18q11-18q23] progressively increased from IgM MGUS and smoldering WM vs. symptomatic WM (18% vs. 20% and 73%, respectively; P =.008), suggesting a multistep transformation of clonal B-cells that albeit benign (i.e.: IgM MGUS and smoldering WM), already harbor the phenotypic and molecular signatures of the malignant Waldenström’s clone.
Project description:Classification of human liver cancer into biologically distinct subgroups suggests origin from different hepatic lineage cells. To clarify contribution of lineage stage in liver oncogenesis, we transduced H-Ras and SV40LT into hepatic progenitor cells (HPC), hepatoblasts (HB) and terminally differentiated adult hepatocytes (AH). Regardless of origin, all transformed cell types acquired common cancer stem cell characteristics in vitro and in vivo. However, expression analysis distinguished tumors of different cellular origin underscoring the contribution of lineage/stage-dependent genetic changes in malignant transformation. Notably, AH-derived tumors showed specific enrichment of c-Myc target genes. These data establish that any hepatic lineage cell can be a target for transformation and acquire common cancer stem cell traits via activation of diverse cell type specific pathways.
Project description:During oncogenic transformation, cells acquire genetic mutations that override the normal mechanisms regulating cellular proliferation. Excessive expression of activating transcription factor 4 (ATF4) is often observed in mammalian malignant tumors. However, little is known about the role of ATF4 in the malignant transformation of normal cells. Here, we show that ATF4 promotes oncogene-induced malignant transformation of murine fibroblasts by suppressing the expression of cellular senescence-associated genes. Ectopic expression of oncogenes, H-rasV12 and simian virus 40 large T-antigen, elicited malignant transformation of embryonic fibroblasts from wild-type mice, but not from Atf4-null (Atf4-/-) mice. The oncogenic stresses induced the expression of both Atf4 and cyclin-dependent kinase inhibitor 2a (Cdkn2a), in wild-type cells. Elevated levels of ATF4 successively suppressed the expression of cdkn2a encoding the cellular senescence-associated proteins, p16INK4a and p19ARF, thereby promoting oncogenic transformation. Conversely, the loss of ATF4 caused cellular senescence resulting from the consistent expression of p16INK4a and p19ARF. These findings reveal a novel function of ATF4: that of promoting oncogenic transformation by suppressing cellular senescence. Total 2 samples were derived from [1] H-Ras and SV40T expressing vector-transfected wild-type mouse embryonic fibroblasts (MEFs) and [2] H-Ras and SV40T expressing vector-transfected Atf4-/- MEFs
Project description:During oncogenic transformation, cells acquire genetic mutations that override the normal mechanisms regulating cellular proliferation. Excessive expression of activating transcription factor 4 (ATF4) is often observed in mammalian malignant tumors. However, little is known about the role of ATF4 in the malignant transformation of normal cells. Here, we show that ATF4 promotes oncogene-induced malignant transformation of murine fibroblasts by suppressing the expression of cellular senescence-associated genes. Ectopic expression of oncogenes, H-rasV12 and simian virus 40 large T-antigen, elicited malignant transformation of embryonic fibroblasts from wild-type mice, but not from Atf4-null (Atf4-/-) mice. The oncogenic stresses induced the expression of both Atf4 and cyclin-dependent kinase inhibitor 2a (Cdkn2a), in wild-type cells. Elevated levels of ATF4 successively suppressed the expression of cdkn2a encoding the cellular senescence-associated proteins, p16INK4a and p19ARF, thereby promoting oncogenic transformation. Conversely, the loss of ATF4 caused cellular senescence resulting from the consistent expression of p16INK4a and p19ARF. These findings reveal a novel function of ATF4: that of promoting oncogenic transformation by suppressing cellular senescence.