Isolation and killing of candidate chronic myeloid leukemia stem cells by antibody targeting of IL-1 receptor accessory protein.
Proc Natl Acad Sci U S A. 2010 Sep 14;107(37):16280-5
Authors: Järås M, Johnels P, Hansen N, Agerstam H, Tsapogas P, Rissler M, Lassen C, Olofsson T, Bjerrum OW, Richter J, Fioretos T
Chronic myeloid leukemia (CML) is genetically characterized by the Philadelphia (Ph) chromosome, formed through a reciprocal translocation between chromosomes 9 and 22 and giving rise to the constitutively active tyrosine kinase P210 BCR/ABL1. Therapeutic strategies aiming for a cure of CML will require full eradication of Ph chromosome-positive (Ph(+)) CML stem cells. Here we used gene-expression profiling to identify IL-1 receptor accessory protein (IL1RAP) as up-regulated in CML CD34(+) cells and also in cord blood CD34(+) cells as a consequence of retroviral BCR/ABL1 expression. To test whether IL1RAP expression distinguishes normal (Ph(-)) and leukemic (Ph(+)) cells within the CML CD34(+)CD38(-) cell compartment, we established a unique protocol for conducting FISH on small numbers of sorted cells. By using this method, we sorted cells directly into drops on slides to investigate their Ph-chromosome status. Interestingly, we found that the CML CD34(+)CD38(-)IL1RAP(+) cells were Ph(+), whereas CML CD34(+)CD38(-)IL1RAP(-) cells were almost exclusively Ph(-). By performing long-term culture-initiating cell assays on the two cell populations, we found that Ph(+) and Ph(-) candidate CML stem cells could be prospectively separated. In addition, by generating an anti-IL1RAP antibody, we provide proof of concept that IL1RAP can be used as a target on CML CD34(+)CD38(-) cells to induce antibody-dependent cell-mediated cytotoxicity. This study thus identifies IL1RAP as a unique cell surface biomarker distinguishing Ph(+) from Ph(-) candidate CML stem cells and opens up a previously unexplored avenue for therapy of CML.
PMID: 20805474 [PubMed - indexed for MEDLINE]
GTPase regulator associated with the focal adhesion kinase (GRAF) transcript was down-regulated in patients with myeloid malignancies.
J Exp Clin Cancer Res. 2010;29:111
Authors: Qian Z, Qian J, Lin J, Yao DM, Chen Q, Ji RB, Li Y, Xiao GF, Li JY
BACKGROUND: GTPase regulator associated with the focal adhesion kinase (GRAF), a putative tumor suppressor gene, is found inactivated in hematopoietic malignancies by either genetic or epigenetic abnormalities. However, the expression level of GRAF gene has not yet been studied in leukemia. The aim of this study was to investigate the expression level of GRAF gene in those patients with myeloid malignancies including acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and chronic myeloid leukemia (CML). METHODS: The expression levels of GRAF transcript were determined in 94 patients using real-time quantitative PCR (RQ-PCR). Clinical and laboratory data of these patients were collected and analyzed. RESULTS: The significantly decreased level of GRAF transcript was observed in three myeloid malignancies compared to controls. Within AML, there was no difference in the level of GRAF transcript among different FAB subtypes (P > 0.05). Difference was not observed in the amount of GRAF mRNA between CML at chronic phase and controls. As CML progressed, GRAF transcript significantly decreased. In MDS, three cases with 5q deletion had lower GRAF transcript than four without 5q deletion (median 0.76 vs 2.99) (P > 0.05). CONCLUSION: our results demonstrate that the GRAF transcript is decreased in myeloid malignancies.
PMID: 20704716 [PubMed - indexed for MEDLINE]
S-trityl-L-cysteine derivative induces caspase-independent cell death in K562 human chronic myeloid leukemia cell line.
Cancer Lett. 2010 Dec 1;298(1):99-106
Authors: Shimizu M, Ishii H, Ogo N, Unno Y, Matsuno K, Sawada J, Akiyama Y, Asai A
Effect of CF(3)-STLC, a potent kinesin spindle protein (KSP) inhibitor, on K562 human CML cell line was investigated. Treatment with CF(3)-STLC induced mitotic arrest of the cell cycle with the appearance of characteristic monoastral spindles, subsequent apoptotic cell death and cleavage of PARP-1, caspase-3, and 4E-BP1. The wide ranging caspase inhibitor z-VAD fmk prevented the cleavage of caspase-3 and 4E-BP1, but failed to attenuate PARP-1 cleavage or cell death triggered by CF(3)-STLC. These results suggest that CF(3)-STLC can induce apoptotic cell death in a caspase-independent manner, and may work effectively as an anti-cancer agent for hematological malignancies.
PMID: 20619960 [PubMed - indexed for MEDLINE]
Methylation status of DDIT3 gene in chronic myeloid leukemia.
J Exp Clin Cancer Res. 2010;29:54
Authors: Wang YL, Qian J, Lin J, Yao DM, Qian Z, Zhu ZH, Li JY
BACKGROUND: DNA-damage-inducible transcript 3 (DDIT3), a candidate tumor suppressor gene (TSG), has been found involved in the regulation of cellular growth and differentiation. The epigenetic changes of TSGs are recently recognized as an abnormal mechanism contributing to the development of chronic myeloid leukemia (CML). The aim of this study was to investigate the methylation status of DDIT3 gene in CML patients. METHODS: The methylation status of DDIT3 promoter was detected in the bone marrow mononuclear cells from 53 patients with CML using methylation-specific PCR (MSP). The expression levels of DDIT3 and bcr/abl transcript were determined by real-time quantitative PCR (RQ-PCR). Clinical data of these patients were collected and analyzed. RESULTS: The aberrant methylation of DDIT3 gene promoter was found in 35 of 53 (66%) CML cases. Correlation was not found between DDIT3 promoter hypermethylation and the age, sex, hemoglobin concentration, platelet counts, chromosomal abnormalities, bcr/abl transcript, and staging of CML patients (P > 0.05), but found between DDIT3 promoter hypermethylation and WBC counts of CML cases (R = 0.781, P < 0.001). The level of DDIT3 transcript in CML patients was significantly lower than that in controls (median 3.28 vs 19.69, P < 0.001), however, there was no difference in the level of DDIT3 transcript between methylation-positive CML cases (0.05-65.32, median 2.13) and methylation- negative CML cases (0.12-126.04, median 3.92) (P > 0.05). CONCLUSION: Our results demonstrate that aberrant methylation of DDIT3 occurs in CML frequently.
PMID: 20492726 [PubMed - indexed for MEDLINE]