OBJECTIVE: To investigate the effect of silencing DNA methyltransferase 1(DNMT1) to the methylation of the promoter of the tumor suppressor gene wnt-1 (WIF-1) in human chronic myeloid leukemia (CML) cells. METHODS: DNMT1 siRNAi plasmid was constructed and DNMT1 siRNAi was transfected into CML K562 cells. RT-PCR and Western blot were used to detect the expression of DNMT1 gene and related protein, and methylation PCR was used to detect WIF-1 gene promoter methylation level. The trypan blue exclusion and MTT assay were used to detect the cell proliferation, flow cytometry were used to detect the cell apoptosis rate, colony formation assay was used to detect cell colony formation ability. Expression of Wnt/β- catenin and its downstream signaling pathway proteins were detected by Western blot after DNMT1 gene was silenced. RESULTS: The expression level of DNMT1 mRNA and its related protein in the experimental group were significantly lower than those in the control group and negative control group (P<0.05). After 72 hours of successful transfection, the WIF-1 gene in the control group and negative control group were completely methylated, while in the experimental group, the methylation level significantly decreased. The results of MSP showed that the PCR product amplified by the unmethylated WIF-1 primer in the experimental group increased significantly,while by the methylated WIF-1 primer decreased significantly. After 48 h of transfection, the OD value, viable cell number and colony formation of the cells in experimental group were significantly lower than those in the negative control group and the control group (P<0.05). The apoptosis rate of the cells in experimental group was significantly higher than those in the negative control group and control group (P<0.05). The expression levels of β- actin, myc, cyclin D1 and TCF-1 in K562 cells in the experimental group were significantly lower than those in the negative control group and control group (P<0.05). CONCLUSION Silencing DNMT1 gene can inhibit the proliferation and promote the apoptosis of K562 cells. The mechanism may be related to reverse the hypermethylation level of the WIF-1 gene promoter, thereby inhibit the activity of the Wnt/β- catenin signaling pathway.
Adaptor Proteins, Signal Transducing/metabolism* ; DNA Methylation ; Humans ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics* ; Repressor Proteins/metabolism*

OBJECTIVETo explore the effects of As(2)O(3) on BCR-ABL protein level and signal transduction in chronic myeloid leukemia (CML) cells.

METHODSImmunoprecipitation, protein tyrosine kinase (PTK) activity assay, real-time Taqman quantitative PCR and Western blot were used.

RESULTSAs(2)O(3) downregulated BCR-ABL protein and STAT1 protein of CML mononuclear cells in the concentrations of 1.0 approximately 2.0 micro mol/L and 0.5 approximately 2.0 micro mol/L after 48 h exposure, respectively. However, p27 protein level was not affected. The PTK activity of BCR-ABL protein was also mildly decreased in CML monouclear cells at 60 h. The bcr-abl mRNA level remained unchanged.

CONCLUSIONAs(2)O(3) downregulats BCR-ABL protein, STAT1 protein, BCR-ABL signal transduction and PTK activity in CML cells.

Fusion Proteins, bcr-abl ; genetics ; Humans ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; Phosphorylation ; drug effects ; Protein-Tyrosine Kinases ; metabolism ; Signal Transduction

OBJECTIVETo detect bcr/abl fusion gene at DNA level in K562 cell line and mononuclear cells from patients with chronic myelogenous leukemia (CML).

METHODSBased on previous research, a set of DNA-PCR primers was redesigned. DNA from K562 cells and mononuclear cells of CML patients was extracted respectively. After DNA-PCR for bcr/abl fusion gene the amplified fragments were then sequenced.

RESULTAt DNA level the bcr/abl fusion gene in K562 cells and mononuclear cells of 2 CML patients was amplified. Furthermore, the DNA breakpoint of fusion gene in the above samples through sequencing of amplified fragments was localized.

CONCLUSIONDNA-PCR offers a new detection technology for bcr/abl fusion without the expression of fusion gene.

Fusion Proteins, bcr-abl ; genetics ; Humans ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; Leukocytes, Mononuclear ; metabolism ; Polymerase Chain Reaction ; methods

OBJECTIVETo investigate the relationship between cyclin D2 and P210(BCR/ABL) tyrosine kinase in chronic myelogenous leukemia (CML).

METHODSRT-PCR, Western blot and flow cytometry were performed to detect the expression of cyclin D2 in K562 cells and in K562-ib-eGFP cells which express intracellular single-chain antibody (sFv, intrabody) against ABL tyrosine kinase domain.

RESULTSCyclin D2 expression in K562-ib-eGFP cells was 18.90% which was lower than that of control K562 cells (48.10%), and the number of S-phase cells in K562-ib-eGFP was 40.40% which was much lower than that in K562 cells (64.34%).

CONCLUSIONCyclin D2 is a potential down-stream signal molecule of the p210(BCR/ABL) tyrosine kinase in CML. The altered expression of cyclin D2 may contribute to the over proliferation of CML cells.

Blotting, Western ; Cyclin D2 ; Cyclins ; analysis ; genetics ; Flow Cytometry ; Genes, abl ; Humans ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVE: To investigate the expression and significance of regulatory T cells (Tregs), FoxP3 and transforming growth factor-β (TGF-β) in different phase of chronic myeloid leukemia (CML). METHODS: Peripheral blood of 73 CML patients in Department of Hematology, Heze Municipal Hospital from March 2018 to March 2021 were collected. According to patient's period in CML, they were divided into ND CML group (newly diagnosed), CP CML group (chronic period), and BP CML group (blast phase). The percentage of Tregs, expression level of FoxP3 mRNA and TGF-β were detected by flow cytometry, RT-qPCR, and ELISA, respecitively. The roles of above indices in clinical pathogenesis of patients with CML were analyzed. RESULTS: The proportion of Treg in the ND CML group was slightly higher than the CP CML group, but the difference was not statistically significant (P =0.695), while the BP CML group was significantly higher than the other two groups (P =0.008, P <0.001). The expression levels of FoxP3 mRNA in ND CML group, CP CML group and BP CML group were 11.61±2.21, 6.46±1.35 and 8.54±2.13, respectively. Significant difference in FoxP3 mRNA levels was observed among patients in different phases of CML (F =55.199, P <0.001). The expression levels of FoxP3 mRNA both in ND CML group and BP CML group were significantly higher than that in CP CML group (P <0.001), and the ND CML group was the highest (P <0.001). However, the expression levels of TGF-β in different phases of CML showed no statistical differences (H =0.634, P =0.728). CONCLUSION The abnormal distribution of Treg subset in different phases of CML and the significant increase of the expression level of FoxP3 mRNA in the new onset and blast phase of CML suggest that Tregs may promote the occurrence and progression of CML through immune regulation.
Humans ; Blast Crisis/metabolism* ; Forkhead Transcription Factors/metabolism* ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics* ; RNA, Messenger/metabolism* ; T-Lymphocytes, Regulatory/metabolism* ; Transforming Growth Factor beta/metabolism*

This study was aimed to investigate the expression of RHBDD1 gene in patients with chronic myeloid leukemia (CML) and explore its clinical significance. The relative expression levels of RHBDD1 in bone marrow mononuclear cells of healthy controls and CML patients were detected by using real time PCR. The results showed that the expression level of RHBDD1 in CML patients was significantly higher than that in healthy controls. The expression level of RHBDD1 in CML patients with negative BCR/ABL p210 was remarkably higher than that in patients with positive BCR/ABL p210. In patients ≥ 50 years old RHBDD1 expression was lower than the patients < 50 years old. There were no significant relation of RHBDD1 expression with sex of patients. It is concluded that RHBDD1 gene may be involved in the pathogenesis and progression of CML, particularly reflects in the pathogenesis of the patients with negative BCR/ABL p210.
Bone Marrow Cells ; metabolism ; pathology ; Case-Control Studies ; Female ; Gene Expression ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; metabolism ; pathology ; Male ; Middle Aged ; Serine Endopeptidases ; genetics ; metabolism

OBJECTIVETo construct a vector containing protein transduction domain (PTD) and bcr/abl fusion gene of chronic myelogenous leukemia and express PTD-bcr/abl fusion protein in E. Coli.

METHODSDNA fragment encoding PTD was synthesized and fused to PCR-amplified bcr/abl gene fragment, then inserted into plasmid pET-16b to get the expression vector pEPb containing PTD-bcr/abl fusion gene, which was transfected and expressed in E. Coli LB21. PTD-bcr/abl fusion protein was purified by affinity chromatography.

RESULTS523 bp bcr/abl fusion gene was effectively amplified. The PTD-bcr/abl gene sequencing showed the same sequence as scheduled. The fusion peptide was successfully expressed in E. Coli and purified.

CONCLUSIONThe results may provide a new PTD-bcr/abl fusion peptide for the immunotherapy of CML.

Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; Fusion Proteins, bcr-abl ; genetics ; metabolism ; Gene Expression ; Gene Products, tat ; genetics ; metabolism ; Genetic Vectors ; genetics ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; Recombinant Fusion Proteins ; genetics ; metabolism

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder characterized by a chromosome translocation that generates the Bcr-Abl oncogene encoding a constitutive kinase activity. Despite remarkable success in controlling CML at chronic phase by Bcr-Abl tyrosine kinase inhibitors (TKIs), a significant proportion of CML patients treated with TKIs develop drug resistance due to the inability of TKIs to kill leukemia stem cells (LSCs) that are responsible for initiation, drug resistance, and relapse of CML. Therefore, there is an urgent need for more potent and safer therapies against leukemia stem cells for curing CML. A number of LSC-associated targets and corresponding signaling pathways, including CaMKII-γ, a critical molecular switch for co-activating multiple LSC-associated signaling pathways, have been identified over the past decades and various small inhibitors targeting LSC are also under development. Increasing evidence shows that leukemia stem cells are the root of CML and targeting LSC may offer a curable treatment option for CML patients. This review summarizes the molecular biology of LSC and its-associated targets, and the potential clinical application in chronic myeloid leukemia.
Animals ; Chemokines ; metabolism ; Epigenesis, Genetic ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; metabolism ; pathology ; Neoplastic Stem Cells ; metabolism ; pathology ; Transcription Factors ; metabolism ; Tumor Microenvironment

Wt1 is a dual-function gene involved in hematopoiesis, leukemogenesis and prognosis for leukemia. This gene is highly expressed in acute myeloid leukemia (AML) and the progression of chronic myelogenous leukemia (CML). It was reported elsewhere that high level of wt1 expression indicated worse prognosis for leukemia. Wt1 gene functions are different due to its subcellular localization. This study was aimed to investigate the expression and localization of wt1 mRNA and WT1 protein, and explore the effects of wt1 inhibitor, curcumin, on K562 cell proliferation, cell cycle and its possible mechanisms. MTT method was used to detect cell proliferation; flow cytometry was used to analyze the alteration of cell cycle, and the immunofluorescence and Western blot technology were performed to observe the subcellular localization of WT1 protein. The transcripts of wt1 and bcr/abl p210 was analyzed by real-time PCR. The results showed that wt1 mRNA and its protein were both highly expressed in K562 cells. The curcumin and imatinib (Glevec) both inhibit the cell proliferation resulting in the G(2)/M and G(0)/G(1) phase arrest respectively. Meanwhile, the transcripts of wt1 and bcr/ablp210 genes decreased greatly after being treated with the two inhibitors above. It is concluded that the alteration of wt1 gene affects the biological characteristics of Ph(+) K562 cells, such as cell proliferation, cell cycle and so on. Gene wt1 is expected to be further studied as a new therapy target in Ph(+) leukemias.
Cell Cycle ; Cell Proliferation ; Curcumin ; pharmacology ; Humans ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; metabolism ; pathology ; RNA, Messenger ; genetics ; WT1 Proteins ; genetics

This study was aimed to investigate the chimerism and fusion gene expression in patients with CML after allo-HSCT, to analyse engraftment and minimal residual disease by using STR-PCR combined with RT-PCR qualitative and quantitative assays, and to evaluate their clinical value for predicting disease relapse. 4 relapsed patients with CML after allo-HSCT were dynamically investigated. Qualitative analysis of donor chimerism was performed by multiplex PCR amplification of STR markers and capillary electrophoresis with fluorescence detection, qualitative detection of bcr/abl transcripts was performed by RT-PCR. The results showed that the 100% donor chimerism appeared in 4 patients on day 28 after transplantation and bcr/abl expression was negative, but the 4 patients were in status of unstable mixed chimerism (DC: 0% - 80.4%) at the different time points during the following up with bcr/abl gene positive. 2 patients of them were continuously mixed chimerism after relapse of CML, the other 2 changed from MC to CC by intervention of clinical treatment. Decreasing values of donor chimerism were detected prior to the occurrence of graft rejection and CML relapse, and bcr/abl gene expression was positive. It is concluded that the results of STR-PCR in the range of its sensitivity fully correspond with bcr/abl tests in patients. The combination of STR-PCR with RT-PCR will provide a highly sensitive and valuable tool for evaluating engraftment, graft rejection, and relapse and predicting GVHD. Furthermore, it can provide a basis for early intervention of clinical treatment, and can identify these high risk patients with molecular or cytogenetic relapse after allo-HSCT.
Fusion Proteins, bcr-abl ; genetics ; metabolism ; Hematopoietic Stem Cell Transplantation ; adverse effects ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; therapy ; Neoplasm Recurrence, Local ; genetics ; Neoplasm, Residual ; diagnosis ; genetics ; RNA, Messenger ; genetics ; metabolism ; Transplantation Chimera ; Transplantation, Homologous