Simultaneous Demonstration of Clonal Chromosome Abnormalities and Apoptosis in Individual Marrow Cells in Myelodysplastic Syndrome

Abstract

Bone marrow samples from 18 patients with myelodysplastic syndrome (MDS) with clonal cytogenetic abnormalities were characterized by combining fluorescence in situ hybridization (FISH) with in situ end-labeling (ISEL) or with annexin V staining and flow cytometry (AV/FLOW) to determine the clonal nature of hematopoietic cells undergoing apoptosis in marrow cells. Apoptosis occurred in both normal and clonal cells. However, the proportion of clonal cells identified by FISH among apoptotic cells was lower than the proportion among nonclonal cells in 17 of 18 patients, regardless of whether ISEL or AV/ FLOW was used to identify apoptosis. This technique allows us to identify simultaneously clonality (as determined by FISH) and apoptosis in individual cells and shows that although apoptosis occurs predominantly in residual normal (FISH-negative) cells, a proportion of clonal precursors in MDS marrow also die from programmed cell death. Such a mechanism may be responsible for the generally slow expansion of the clone in MDS.

Transcriptional regulation of miR-10a/b by TWIST-1 in myelodysplastic syndromes

“…Pearson's linear regression haematologica | 2013; 98(3) . Cells were co-cultured with HS5 stroma as described 18 …”

The helix-loop-helix transcription factor TWIST is dysregulated in myelodysplastic syndromes

“…[2][3][4] MDS has been considered a cell-autonomous disorder, and various mutations in hematopoietic cells have been described; however, recent data indicate that, in addition, cellular and noncellular components of the marrow microenvironment are involved in the pathophysiology of MDS and contribute to the broad spectrum of clinical presentations. [5][6][7] We and others have shown that, particularly in early stage/low-grade MDS, apoptosis occurs in both residual normal (polyclonal) and clonal hematopoietic precursors, 8,9 albeit at a consistently lower rate in clonal cells. 8 This lower apoptotic rate is associated with a survival advantage of the clone.…”

“…[5][6][7] We and others have shown that, particularly in early stage/low-grade MDS, apoptosis occurs in both residual normal (polyclonal) and clonal hematopoietic precursors, 8,9 albeit at a consistently lower rate in clonal cells. 8 This lower apoptotic rate is associated with a survival advantage of the clone. With more advanced MDS, clonal hematopoietic precursors become increasingly resistant to proapoptotic signals 8 and in a proportion of patients MDS will evolve to acute myeloid leukemia (AML).…”

Dysregulation of IL-32 in myelodysplastic syndrome and chronic myelomonocytic leukemia modulates apoptosis and impairs NK function

“…Whereas patients with MPD show proliferative characteristics in the bone marrow, apoptosis is prominent in patients with MDS. Cytokines such as TNF␣, and the proapoptotic Fas-ligand and TNF-related apoptosisinducing ligand (TRAIL), are up-regulated in patients with MDS (3), and the neutralization of TNF␣ (4-6), for example with the soluble TNF receptor etanercept (7), enhances hematopoiesis in vitro and in vivo (6,8,9). TNF␣ is of particular interest because, in addition to proinflammatory activity, it provides both proapoptotic and proliferative signals (9).…”

“…TNF␣ is of particular interest because, in addition to proinflammatory activity, it provides both proapoptotic and proliferative signals (9). In early stage MDS, apoptosis occurs in both residual normal and clonal hematopoietic precursors (8). The rate of apoptosis in clonal precursors declines as the disease progresses.…”