Objective To investigate the point mutations within the adenosine triphosphate-binding region of BCR/ABL in patients with chronic myeloid leukemia who develop imatinib resistance.Methods We collected a total of 17 bone marrow samples obtained from 11 patients who showed hematology resistance (n = 7)or cytogenetic refractoriness(n = 4).A long semi-nest PCR method was used to amplify the ABL kinase domain of the BCR/ABL allele.After two rounds of PCR reactions,we got a fragment of 863 bases The PCR products were purified and followed by sequencing.Results In total,we find three point mutations presented in all patients tested G250E,E255K and T315I.The mutation rate of hematology resistance is 4/ 7,and 95% confidence interval was 8%-90%,while mutation rate of cytogenetic refractoriness 1/4,95% confidence interval 1%-81%.For those patients whose samples were available,no single mutation were determined before imatinib resistance emerged.Conclusions There is high frequency of point mutations clustered within the adenosine triphosphate-binding region of BCR/ABL in patients with chronic myeloid leukemia.It's good for patients to switch to another therapeutic strategy when the mutations are detected.

To elucidate the effect of established primary bone marrow stromal layers on the gene transduction of human hematopoietic stem/progenitor cells (HSC/HPC), mononuclear cells (MNC) from adult bone marrow were isolated by centrifugation on Ficoll-Hypaque gradients and plated in stromal culture medium. The cells were incubated until passage 4 to establish primary stromal layers. The HSC/HPC prestimulated by cytokines were transduced by retroviral supernatant containing mdr1 gene in presence of irradiated stroma-contact support. Transduced cells were plated in a colony-forming unit assay with and without vincristine (VCR) to assess the efficiency of transduction. Individual colonies were also analyzed by polymerase chain reaction (PCR) for the presence of provirus. The results showed that the mixed adherent cell layers were formed when adult bone marrow stromal cells were incubated for four to six weeks, mainly being composed of fibroblasts. In the presence of stroma-contact support, the average of gene transduction efficiency in marrow-derived progenitors increased 2.1 to 3.3 folds measured by colony-forming assay and/or PCR, significantly higher than those without support of stroma. It is concluded that the presence of bone marrow stroma support in combination with cytokine facilitates augmenting the extent of retroviral-mediated gene transduction.
Bone Marrow Cells ; physiology ; Genes, MDR ; Hematopoietic Stem Cells ; metabolism ; Humans ; Retroviridae ; genetics ; Stromal Cells ; physiology ; Transduction, Genetic

OBJECTIVETo explore the effect of down-regulation of insulin-like growth factor binding protein 7 (IGFBP7) on the proliferation and invasiveness of leukemia cell line U937 cells.

METHODSThree pairs of double-strand siRNA targeting IGFBP7 gene were transfected into SMMC7721 cells to select the most efficient one for U937 cells. qRT-PCR and Western blot were used to detect the expression of IGFBP7 in U937 cells after transiently transfected with siRNA of IGFBP7. Cell proliferation, adhesion, trans-endothelial migration and invasion were performed in transfected cells and control groups.

RESULTSAfter transfected with siRNA of IGFBP7 in U937 cells, the ability of cell proliferation was significantly decreased at 24 h (0.580 ± 0.159) compared to that of parental cells and scramble negative control (1.049 ± 0.274, 0.946 ± 0.195, respectively) (P < 0.01). Adhesion of U937 cells transfected with IGFBP7 gene specific siRNA to ECV304 cells was significantly lower than that of the control groups (0.247 ± 0.031 vs 0.406 ± 0.023 and 0.395 ± 0.011) (P < 0.01). Transendothelial membrane of U937 cells into the bottom of the 24-well plate for experimental group were less than those in the control groups \[(0.387 ± 0.021)×10(5) vs (1.017 ± 0.031)×10(5) and (0.908 ± 0.027)×10(5)\]. Cells adherent to the matrigel for experimental group were less than those in the control groups \[(0.197 ± 0.098)×10(5) vs (0.493 ± 0.067)×10(5) and (0.469 ± 0.083)×10(5)\]. The difference was significant (P < 0.01).

CONCLUSIONIGFBP7 gene plays a contributing role in leukemogenesis involving in leukemic cells' proliferation and interaction with endothelial cells through adhesion, invasion and migration.

Cell Proliferation ; Down-Regulation ; Humans ; Insulin-Like Growth Factor Binding Proteins ; genetics ; metabolism ; Leukemia, Myeloid, Acute ; metabolism ; pathology ; Transfection ; U937 Cells

cDNA microarray, recently applied to analyze gene expression profile of cancers, was difficult to be utilized in myelodysplastic syndrome (MDS) for a special need of excessive mRNA hardly provided by ordinary bone marrow aspiration in MDS patients. The aim of this study was to investigate the feasibility of exploring the molecular events underlying MDS by using cDNA microarray and mixing mRNA from multiple patients. A commercially purchased BioStar H141 cDNA microarray containing 14,110 clones of cDNA or EST was employed to analyze the gene expression profile of bone marrow mononuclear cells from two cases of MDS. Equal amount of total RNA from each patient was mixed, reversely transcribed to cDNA and labeled with Cy5. Mixture of Cy5-labeled cDNA and Cy3-labeled cDNA from normal bone marrow cells was concomitantly hybridized to H141 microarray in duplicate. In H141 chips, 1,064 cDNAs were spotted at least twice targeting different fragments of a single gene cDNA. The results showed that among these 1,064 cDNA clones, the expression level of 625 (58.7%) and 630 (59.2%) ones was consistent within these two chips, respectively, 297 (27.9%) and 191 (18.0%) inconsistent, 21 (2.0%) and 11 (1.0%) in opposite. Among 411 duplicately spotted cDNAs with complete data, expression levels of 400 (97.3%) was consistent between two chips. 488 genes with known function were identified as differentially expressed in MDS, among which 101 genes were involved in hematopoiesis regulation, including those encoding transcription factors, cell cycle-regulating proteins, metabolism-relating enzymes, and adhesive molecules. It is concluded that cDNA microarray can be used for profiling gene expression of mixed MDS samples and replication shall be necessary for reducing the data bias caused by experimental operation.
Bone Marrow Cells ; metabolism ; Gene Expression Profiling ; Humans ; Leukocytes, Mononuclear ; metabolism ; Male ; Middle Aged ; Myelodysplastic Syndromes ; metabolism ; Oligonucleotide Array Sequence Analysis ; Reproducibility of Results

OBJECTIVETo explore the effects of anti-CD44 monoclonal antibody-IM7 on the in vitro adhesion and migration of chronic myeloid leukemia stem cell (CML-LSC) and its mechanism.

METHODSCD34(+)CD38(-)CD123(+) leukemic stem cells (LSC) from 20 newly-diagnosed chronic myeloid leukemia (CML) patients BM cells and CD34(+)CD38(-) hematopoietic stem cells (HSC) from 20 full-term newborn cord blood cells were isolated with EasySep(TM) magnet beads. The CD44 expression of the LSC and HSC was detected by flow cytometry (FCM), and the adhesion and migration ability of the LSC and HSC pre- and post-incubated with IM7 in vitro by MTT assay and transendothelial migration assay, respectively.

RESULTS(1) After incubated with IM7, the LSC and HSC CD44 expression rates were (86.60 ± 2.10)% vs. (25.40 ± 1.70)% (P < 0.05), respectively. (2) The adhesive ability of the LSC to endothelial cells was decreased markedly after incubated with IM7, the OD value (A(570)) changing from pre-incubation of (0.62 ± 0.11) to post-incubation of (0.34 ± 0.07), while there was little change of A(570) in the HSC group. (3) The migration ability of the LSC group was inhibited evidently after incubated with IM7, the inhibition rate being 46% ∼ 63%, while little change of that in HSC group was detected. (4) The adhesive ability of the LSC group to marrow stromal cells was decreased markedly after incubated with IM7, while little change was found in that of HSC group.

CONCLUSIONThe anti-CD44 monoclonal antibody-IM7 can effectively inhibit the adhesion and migration abilities of the LSC in vitro, which might provide a theoretical evidence for targeting therapy.

Antibodies, Monoclonal ; pharmacology ; Antigens, CD34 ; metabolism ; Bone Marrow ; drug effects ; Flow Cytometry ; Hematopoietic Stem Cells ; drug effects ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; metabolism

To explore the feasibility of real-time quantitative PCR (QRT-PCR) for selecting cell strains which overexpress a certain transgene, expression level of RbAp46 was detected in transfected cell strains by using optimal real-time PCR with SYBR Green I. Meanwhile, semi-quantitative RT-PCR and Western blot were performed to compare with the QRT-PCR. The results showed that values of RbAp46(N) were 2064.42 +/- 253.47, 860.94 +/- 291.07, 234.456 +/- 31.08, 18.17 +/- 5.14 and 1.46 +/- 0.54 in K562/RbAp46, K562/CMV, SHG44/RbAp46 monoclone, SHG44/RbAp46 multiclone and SHG44/CMV, respectively. The results were consistent with that determined by semi-quantitative RT-PCR and Western blot. It is concluded that QRT-PCR provides a highly efficient and reproducible method for selection of transfected cell subclones at different level of transgene expression.
Blotting, Western ; Carrier Proteins ; genetics ; metabolism ; Gene Expression Regulation, Neoplastic ; Humans ; K562 Cells ; Nuclear Proteins ; genetics ; metabolism ; Organic Chemicals ; chemistry ; RNA, Neoplasm ; metabolism ; Retinoblastoma-Binding Protein 7 ; Reverse Transcriptase Polymerase Chain Reaction ; methods ; Transfection ; Transgenes ; genetics

In order to study the potential effects of exogenous WT1 gene isoform on apoptosis in leukemia cell line NB4 and its possible molecular mechanisms, the eukaryotic expression recombinant vector (pCB6(+)/WTA) containing full-length human WT1 isoform (WTA: -17aa/-KTS) cDNA and the vacant vector-alone were introduced into the leukemia cell line NB4 respectively by electroporation. The WTA mRNA and protein in cells were detected by RT-PCR and Western blot. Binding of Annexin V were tested by flow cytometry and agarose gel electrophoresis to verify whether exogenous WTA could induce apoptosis of NB4 cells. Expressions of p21, p53, bcl-2, bcl-XL and c-myc genes were determined by semi-quantitative RT-PCR after introducing recombinant vectors into the NB4 cells. The results showed that in exposure to As(2)O(3) at 0.8 micromol/L for 48 hours, the NB4/WTA cells exhibited the morphological hallmarks of apoptosis, the marked DNA ladder shown by gel electrophoresis, and the enhanced apoptosis rate marked by Annexin V. RT-PCR showed an increase in p21 and c-myc genes expression, a decrease in bcl-2 and a relative constant expression of p53, bcl-XL in NB4/WTA cells. It is concluded that the introduction and expression of exogenous WTA gene can lead to apoptosis of NB4/WTA cells by down-regulating the Bcl-2 gene expression and up-regulating the p21 and c-myc genes expression.
Apoptosis ; genetics ; physiology ; Blotting, Western ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; Gene Expression Regulation, Neoplastic ; Humans ; Leukemia ; genetics ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; Proto-Oncogene Proteins c-myc ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection ; Tumor Suppressor Protein p53 ; genetics ; WT1 Proteins ; genetics ; metabolism ; physiology ; bcl-X Protein ; genetics

To elucidate the possible mechanism of differentiation and/or apoptosis in NB4, K562 cells induced by tributyrin (TB), a histone deacetylase inhibitor (HDACi), the level of acetylated histone H3 was detected by Western blot, p21(WAF1) expression was detected by semi-quantitative RT-PCR. The results showed that histone H3 hyperacetylation was detected in NB4 (or K562) cells after treatment with TB 0.1 mmol/L (or TB 0.5 mmol/L) for 16 hours in a dose-dependent manner. p21(WAF1) dose-dependently increased at RNA level in these two cell lines treated by TB 0.1 mmol/L. The level of p21(WAF1) mRNA increased at 2 hours after TB treatment, reaching peak at 16 hours, and maintaining for 48 hours. In conclusion, the mechanism of differentiation and apoptosis in NB4, K562 cells induced by tributyrin may associate with its up-regulation of acetylated histone and p21(WAF1) mRNA level.
Acetylation ; drug effects ; Apoptosis ; drug effects ; Blotting, Western ; Cell Differentiation ; drug effects ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; Dose-Response Relationship, Drug ; Enzyme Inhibitors ; pharmacology ; Gene Expression Regulation, Neoplastic ; drug effects ; Histone Deacetylase Inhibitors ; Histone Deacetylases ; metabolism ; Histones ; metabolism ; Humans ; K562 Cells ; Leukemia ; genetics ; metabolism ; pathology ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Triglycerides ; pharmacology

OBJECTIVETo study the expression ratio of AML1-ETO9a (AE9a) isoform in t(8;21) acute myeloid leukemia (AML) and its clinical significance.

METHODSBone marrow samples from 44 newly diagnosed t(8;21) AML patients co-expressed AE9a and AE were screened by RT-PCR. The alteration of the AE9a expression ratio was monitored during follow-up by using quantitative real-time RT-PCR (qPCR).

RESULTSThe expression level of AE9a was markedly lower than that of AE in these patients. There was a positive correlation between the expression level of AE9a and AE in most of bone marrow samples. The transcript level of both AE9a and AE was decreased in the 44 patients after one course of standard chemotherapy, but the percentage of AE9a expression level was increased in comparison with that before treatment (P < 0.05). After one course of standard chemotherapy treatment, the percentage of AE9a in incomplete remission (ICR) patients was significantly higher than that in CR patients (P < 0.05). Relapsed patients had a higher AE9a ratio than the unrelapsed patients (P < 0.05). During the remission, the percentage of AE9a in 11/17 relapsed patients obviously elevated even while the expression of AE fusion gene at low level.

CONCLUSIONSAE9a and AE co-expressed in most of AML patients with t(8;21) translocation. The expression level of AE9a was lower than that of AE, and there is a positive correlation between the expression level of these two isoforms. The sensitivity of AE9a gene to the standard chemotherapy is less than that of the AE fusion gene. Monitoring the AE9a to AE ratio during the CR can predict the early relapse of the disease compared to monitoring the AE alone.

Adolescent ; Adult ; Child ; Chromosomes, Human, Pair 21 ; Chromosomes, Human, Pair 8 ; Core Binding Factor Alpha 2 Subunit ; genetics ; Female ; Gene Expression ; Humans ; Leukemia, Myeloid, Acute ; genetics ; pathology ; Male ; Middle Aged ; Oncogene Proteins, Fusion ; genetics ; Protein Isoforms ; genetics ; RUNX1 Translocation Partner 1 Protein ; Translocation, Genetic ; Young Adult

Acute Disease ; Blast Crisis ; genetics ; Genes, Retinoblastoma ; Genes, Wilms Tumor ; Humans ; Leukemia ; genetics ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; pathology ; Polymerase Chain Reaction ; U937 Cells