BACKGROUND: Imatinib mesylate (IM) resistance is an emerging problem for chronic myeloid leukemia (CML). Previous studies found that connexin 43 (Cx43) deficiency in the hematopoietic microenvironment (HM) protects minimal residual disease (MRD), but the mechanism remains unknown. METHODS: Immunohistochemistry assays were employed to compare the expression of Cx43 and hypoxia-inducible factor 1α (HIF-1α) in bone marrow (BM) biopsies of CML patients and healthy donors. A coculture system of K562 cells and several Cx43-modified bone marrow stromal cells (BMSCs) was established under IM treatment. Proliferation, cell cycle, apoptosis, and other indicators of K562 cells in different groups were detected to investigate the function and possible mechanism of Cx43. We assessed the Ca 2+ -related pathway by Western blotting. Tumor-bearing models were also established to validate the causal role of Cx43 in reversing IM resistance. RESULTS: Low levels of Cx43 in BMs were observed in CML patients, and Cx43 expression was negatively correlated with HIF-1α. We also observed that K562 cells cocultured with BMSCs transfected with adenovirus-short hairpin RNA of Cx43 (BMSCs-shCx43) had a lower apoptosis rate and that their cell cycle was blocked in G0/G1 phase, while the result was the opposite in the Cx43-overexpression setting. Cx43 mediates gap junction intercellular communication (GJIC) through direct contact, and Ca 2+ is the key factor mediating the downstream apoptotic pathway. In animal experiments, mice bearing K562, and BMSCs-Cx43 had the smallest tumor volume and spleen, which was consistent with the in vitro experiments. CONCLUSIONS Cx43 deficiency exists in CML patients, promoting the generation of MRD and inducing drug resistance. Enhancing Cx43 expression and GJIC function in the HM may be a novel strategy to reverse drug resistance and promote IM efficacy.
Animals ; Humans ; Mice ; Apoptosis ; Bone Marrow Cells ; Cell Communication ; Connexin 43/genetics* ; Gap Junctions/metabolism* ; Imatinib Mesylate/therapeutic use* ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology* ; Mesenchymal Stem Cells/metabolism* ; Tumor Microenvironment ; Calcium/metabolism*

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*

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*

INTRODUCTIONThe prognosis of patients with chronic myeloid leukaemia (CML) has improved since the introduction of imatinib. However, patients who do not achieve complete cytogenetic response (CCyR) and major molecular response (MMR) have poorer prognosis. Recent clinical trials have demonstrated that early and deeper cytogenetic and molecular responses predict a better long-term outcome. This study aimed to analyse the relationship between early molecular response and clinical outcome in a real-life setting.

METHODSThis retrospective study included all patients with CML, in chronic or accelerated phase, who were treated with imatinib at University of Malaya Medical Centre, Malaysia.

RESULTSA total of 70 patients were analysed. The median follow-up duration was 74 months, and the cumulative percentages of patients with CCyR and MMR were 80.0% and 65.7%, respectively. Overall survival (OS) and event-free survival (EFS) at ten years were 94.3% and 92.9%, respectively. Patients who achieved CCyR and MMR had significantly better OS and EFS than those who did not. At six months, patients who had a BCR-ABL level ≤ 10% had significantly better OS and EFS than those who had a BCR-ABL level > 10%. The target milestone of CCyR at 12 months and MMR at 18 months showed no survival advantage in our patients.

CONCLUSIONOur data showed that imatinib is still useful as first-line therapy. However, vigilant monitoring of patients who have a BCR-ABL level > 10% at six months of treatment should be implemented so that prompt action can be taken to provide the best outcome for these patients.

Academic Medical Centers ; Adult ; Antineoplastic Agents ; therapeutic use ; Cytogenetics ; Disease-Free Survival ; Female ; Follow-Up Studies ; Fusion Proteins, bcr-abl ; metabolism ; Humans ; Imatinib Mesylate ; therapeutic use ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; diagnosis ; drug therapy ; genetics ; Malaysia ; Male ; Middle Aged ; Predictive Value of Tests ; Prognosis ; Retrospective Studies ; Treatment Outcome ; Universities

No abstract available.
Aged ; Cytidine Deaminase/*genetics/metabolism ; Dasatinib/therapeutic use ; Disease Progression ; Drug Resistance, Neoplasm ; Fusion Proteins, bcr-abl/genetics/metabolism ; Humans ; Imatinib Mesylate/*therapeutic use ; In Situ Hybridization, Fluorescence ; Karyotype ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/*drug therapy ; Male ; Microfilament Proteins/*genetics/metabolism ; Oncogene Proteins/*genetics/metabolism ; Protein Kinase Inhibitors/*therapeutic use

No abstract available.
Bone Marrow/pathology ; Chromosomes, Human, Pair 12 ; Chromosomes, Human, Pair 9 ; Core Binding Factor Alpha 2 Subunit/*genetics ; DNA/metabolism ; Gene Rearrangement ; Humans ; In Situ Hybridization, Fluorescence ; Karyotyping ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis/*genetics ; Male ; Middle Aged ; Oncogene Proteins, Fusion/*genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Translocation, Genetic

No abstract available.
Aged, 80 and over ; Base Sequence ; Bone Marrow/pathology ; DNA/chemistry/metabolism ; Female ; Fusion Proteins, bcr-abl/*genetics ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis/*genetics ; Multiplex Polymerase Chain Reaction ; Protein Isoforms/genetics ; Sequence Analysis, DNA

OBJECTIVETo explore the mRNA expression level of Notch1 and ASB2 in bone marrow mononuclear cells of patients with P210(+) chronic myeloid leukemia and the correlation between Notch signaling pathway and ubiquitination in chronic myeloid leukemia, so as to provide the valuable information for investigating the pathogenesis of chronic myeloid leukemia and clinical treatment.

METHODSBone marrow was collected from 32 patients with newly diagnosed chronic myeloid leukemia and 34 non-hematopathic and healthy individuals (control group), respectively. The mRNA expression levels of Notch1 and ASB2 were detected by real-time quantitative PCR.

RESULTSThe expression of Notch1 mRNA in CML patients were significantly different from that of healthy individuals group (t=36.3, P<0.01), which was 337.8 times of the healthy individuals. Moreover, the expression level of ASB2 mRNA in CML group was significantly higher than that in healthy individuals (t=19.4, P<0.01). The mRNA expression of Notch1 and ASB2 gene was positive correlation (r=0.504, P<0.01).

CONCLUSIONThe aberrant expression of Notch1 and Asb2 exists in patients with P210 positive CML, which may be involved in incidence and development of CML.

Bone Marrow ; metabolism ; Case-Control Studies ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Receptor, Notch1 ; genetics ; metabolism ; Signal Transduction ; Suppressor of Cytokine Signaling Proteins ; genetics ; metabolism

OBJECTIVETo investigate the methylation status of miR-378 promoter in chronic myeloid leukemia (CML) and to analyze its clinical significance.

METHODSThe unmethylation level of miR-378 gene promoter in bone marrow mononuclear cells of 25 healthy donors and 53 patients with CML was detected by using real-time quantitative methylation-specific PCR (RQ-MSP).

RESULTSThe hypomethylation of miR-378 gene promoter was found in 17/53 (32.1%) patients, but only in 1/25 (4.0%) of controls. The difference between the two groups was very statistically significant (P < 0.01). The frequency of miR-378 unmethylation in CML patients at chronic phase (CP), accelerated phase (AP) and blastic phase (BP) was 35.0% (14/40), 40.0% (2/5), and 12.5% (1/8), respectively. However, there were no significant differences in the unmethylation level of miR-378 among CML patients at different sexes, stages and karyotypes. No significant differences could be observed in age, white blood cell counts, platelet count, hemoglobin level and BCR/ABL1 transcript level (P > 0.05). CONCLUDSION: The miR-378 hypomethylation is a common molecular event in CML, especially at chronic or accelerated phases.

Bone Marrow Cells ; metabolism ; Case-Control Studies ; DNA Methylation ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; MicroRNAs ; metabolism ; Promoter Regions, Genetic

Cryptotanshinone (CPT), a lipid soluble active compound in Salvia miltiorrhiza, has a significant inhibitory effect on multiple malignant tumors, e. g. chronic myeloid leukemia (CML) cells and can effectively enhance imatinib's chemotherapeutic effect. However, its functional molecular mechanism remained unclear. In this experiment, the authors conducted a systematic study on the effect of CPT on the imatinib sensitivity and P-glycoprotein (P-gp) expression in CML cells by using CML cells K562 and imatinib persister K562-R. The MTT assays were performed to determine CPT's impact on the inhibitory effect of imatinib. Annexin V-FITC/PI staining analysis was used to detect the changes in the cell apoptosis rate. The active changes in apoptosis regulatory proteins Caspase-3, Caspase-9 and PARP were determined by Western blot. After the cells were pretreated with the gradient concentration of CPT, the expression of P-gp was analyzed by Western blot and flow cytometry. The changes in intracellular concentrations of imatinib were determined by HPLC analysis. The results indicated that the pretreatment with CPT significantly increased the proliferation inhibiting and apoptosis inducing effects of imatinib on K562 and K562-R cells as well as the degradation product expression of pro-apoptotic proteins Caspase-3, Caspase-9 and PARP, with a significant difference with the control group (P < 0.01). However, CPT showed no impact on the P-gp expression in CML cells and the intracellular concentrations of imatinib. In summary, the findings suggested that CPT enhanced the sensitivity of CML cells to imatinib. Its mechanism is not dependent on the inhibition in P-gp expression and the increase in intracellular drug concentration.
ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; metabolism ; Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Caspase 3 ; genetics ; metabolism ; Caspase 9 ; genetics ; metabolism ; Drug Resistance, Neoplasm ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Humans ; Imatinib Mesylate ; pharmacology ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; drug therapy ; genetics ; metabolism ; physiopathology ; Phenanthrenes ; pharmacology