Efficient long-term maintenance of chronic myeloid leukemic cobblestone area forming cells on a murine stromal cell line

Abstract

represent spleen colony-forming stem cells (CFU-S day-12), cobblestone area whereas the cells giving rise to late appearing, more permanent CAs are related to primitive stem cells with long-term in vivo repopulating ability. 21,[24][25][26] Similarly, in the human CAFC assay both the phenotypes of the CAFC subsets 23 and the in vivo repopulation data in SCID mice 27,28 and men 29 are conIntroduction cordant with the assumption that CAFC wk 2-3 represent more transiently repopulating stem cells, whereas CAFC wk Chronic myeloid leukemia (CML) is a malignant disorder aris-5-8 are indicators of stem cells that induce stable chimerism ing from a pluripotent hematopoietic stem cell. 1 The disease in vivo. We have previously shown that the FBMD-1 stromal is characterized by excessive production of mature blood cells cell line allows long-term growth of AML leukemic stem belonging predominantly to the myeloid lineage. Malignant cells. 30 In the present study we have investigated the possicells are characterized cytogenetically by a translocation bility of propagating CML stem cells over an extended period between chromosomes 9 and 22 (t(9;22)) and, at the molecuof time in order to improve the analysis of their frequency and lar level, by the bcr/abl hybrid gene resulting from the transpoability to generate committed progenitors. sition of the c-abl proto-oncogene on chromosome 9 to the breakpoint cluster region (bcr) on chromosome 22. sent from CML patients in first chronic phase.

An in vitro model for cytogenetic conversion in CML. Interferon-alpha preferentially inhibits the outgrowth of malignant stem cells preserved in long-term culture.

“…Median percentages of CD34 ϩ /Ph ϩ NC did not differ between the two groups of patients, although a wider range was observed in progenitor cells from responding patients (27-95%). In both responders and nonresponders, the percentage of Ph ϩ cells did not change significantly during 8 wk of LTC in the absence of IFN-␣, con- firming earlier findings that LTC on the FBMD-1 stromal cell line equally supports outgrowth of Ph ϩ and Ph Ϫ progenitors (25). The percentage of Ph ϩ NC produced by progenitor cells from nonresponders did not change over 8 wk of LTC in the presence of IFN-␣.…”

“…Furthermore, we have shown recently that the FBMD-1 stromal cell line allows long-term growth of leukemic stem cells (24,25). Both leukemic and normal stem cells obtained from individual CML patients were maintained efficiently throughout LTC (25). Such LTC provides a model to evaluate differential effects of cytokines or drugs on normal and malignant stem cells in CML.…”

“…Early appearing, transient CAs represent spleen colony-forming stem cells (CFU-S day 12), whereas cells giving rise to late appearing CAs are related to primitive stem cells with long-term repopulating ability (23). Furthermore, we have shown recently that the FBMD-1 stromal cell line allows long-term growth of leukemic stem cells (24,25). Both leukemic and normal stem cells obtained from individual CML patients were maintained efficiently throughout LTC (25).…”

Biological characteristics and prognosis of adult acute myeloid leukemia with internal tandem duplications in the Flt3 gene

“…We have now investigated whether the presence of Flt3/ITDs in AML cases within the adult population correlated with (1) their short-term proliferative response to single cytokine stimulation; (2) the ability of these cells to engraft in the bone marrow of immunodeficient mice (NOD/SCID) [24][25][26] and (3) the frequency of leukemic progenitor and stem cells, as measured by a leukemic cobblestone area forming cell assay (L-CAFC). 27,28 Furthermore, we have analyzed whether the presence of Flt3/ITDs in AML in the Dutch population of patients predicts prognosis, as was recently published for the Japanese population. 29 …”

Chronic myeloid leukemia from basics to bedside

“…403 However, prolonged maintenance of these cells was possible using murine stromal feeder layers. 404 Moreover, autografting of bone marrow cultured for 10 days was shown to deliver multilineage reconstitution. 405 In total 22 patients have been autografted after 10 days in vitro culture by the Vancouver group.…”