The Bcr-Abl oncogene is produced by the reciprocal translocation between c-Abl gene on chromosome 9 and the Bcr gene on chromosome 22 in human genome. The encoded Bcr-Abl fusion protein is responsible for the pathogenesis of certain human leukemias. Abelson murine leukemia virus (A-MuLV) is a retrovirus that could lead to transformation of B lymphocyte in mice, and v-Abl is the oncogene of A-MuLV. Abl oncoproteins (such as Bcr-Abl and v-Abl) play critical roles in tumorigenesis of certain cell types. Several signal transduction pathways, including JAK/STAT/Pim, PI3K/AKT/mTOR and RAS/RAF/MEK signaling pathway, are involved in Abl-mediated tumorigenesis. In addition, Abl-mediated tumorigenesis is associated with mutation or abnormal modification of key signal molecules as well as dysregulation of some critical long noncoding RNAs (lncRNAs). Here, we review the molecular mechanisms by which Abl oncogenes activate three major signaling pathways, and provide a scientific basis for therapy of Abl oncoprotein-induced tumors.
Abelson murine leukemia virus ; Animals ; Cell Transformation, Neoplastic ; Fusion Proteins, bcr-abl ; Genes, abl ; Humans ; Phosphatidylinositol 3-Kinases

OBJECTIVETo establish a fluorogenic probe quantitative RT-PCR (FQ-RT-PCR) method for detection of bcr/abl mRNA fusion gene expression level in leukemia cells, and provide a useful tool for leukaemia diagnosis and minimal residual disease inspectation.

METHODThe conventional RT-PCR was used to amplify bcr/abl gene from cultured K562 cells, the quantitative standard template was constructed with A-T clone method. The fluo-rogenic quantitative RT-PCR method by using Applied Biosystems 7700 Sequence Detector for detecting the expression of bcr/abl fusion gene was successfully. The sensitivity, stability and repetitiveness of this method was determined. The peripheral blood samples from 14 CML patients, one of whom before and one month after bone marrow transplantation (BMT) and 4 cases of ALL in the early stages were detected.

RESULTSThe sensitivity of FQ-RT-PCR for detecting bcr/abl fusion gene was about 10(-5) micro g RNA from K562 cell and 10 copies recombined plasmid. The repetition CT value (cycle threshold) and the coefficient variation (CV) among tubes and batches were 2.0% and 3.7%, respectively. The median bcr/abl fusion gene expression level of 14 CML patients was 5.15 x 10(4) copies/ micro g RNA. The products analyzed by electrophoresis showed that 11 cases were b2a2 and 3 cases b3a2. 1.2 x 10(5) copies/ micro g RNA in one CML patient before BMT was changed to 2.3 x 10(3) copies/ micro g RNA one month after BMT. B2a2 was observed in one of the four (25.0%) patients with ALL, and its level of expression was 8.2 x 10(5) copies/ micro g RNA.

CONCLUSIONThe established FQ-RT-PCR method is sensitive, specific, reliable, accurate and good at repetitiveness. The results expressed in copies were easy for evaluation and comparation. Two different bcr/abl fusion gene form - b2a2, b3a2 can be detected by the method. It can be widely applied to diagnosis and detection of minimal residual disease for CML and some ALL patients.

Fusion Proteins, bcr-abl ; genetics ; Genes, abl ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; RNA, Messenger ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVE: To explore the expression level of ETV6-ABL fusion gene in different cell populations in patients with myeloproliferative neoplasm (MPN) and therapeutic effect of tyrosine kinase inhibitor (TKI). METHODS: A 42-year-old man who presented with fever, marked leukocytosis and chronic myelogenous leukemia (CML) like MPN was reported. ETV6-ABL fusion gene was detected by real-time PCR and confirmed by direct sequencing. ETV6-ABL mRNA expression in each cell population sorted from peripheral blood by flow cytometry was detected by real-time PCR. RESULTS: ETV6-ABL fusion gene was found out in bone marrow cells and confirmed as type A by direct sequencing. ETV6-ABL fusion gene transcript level in polymorphonuclear cells was nearly 3.6-fold relative to that in total cells, which was significantly higher than that in T cell, B cell and monocyte subsets. The complete blood count (CBC) returned to normal level after treatment with imatinib (400 mg) daily for three months. After TKI treatment for 6 months, the ratio of ETV6-ABL/ABL decreased from 174.1% to 1.9%. CONCLUSION ETV6-ABL fusion gene positive MPN may have a CML clinical presentation and is sensitive to TKI. ETV6-ABL fusion gene is specifically expressed in polymorphonuclear cells.
Adult ; Fusion Proteins, bcr-abl/genetics* ; Genes, abl ; Hematopoietic Stem Cell Transplantation ; Humans ; Imatinib Mesylate ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics* ; Male ; Myeloproliferative Disorders/genetics*

The blast phase in chronic myelogenous leukemia (CML) is associated with mutation of several genes. It is well known that p53 gene mutation plays a key role in the myeloid or lymphoid blast phase of CML. But for the case of the N-ras gene, the association between N-ras mutations and the blast phase of CML is not yet known. We report here on a case of detecting N-ras point mutation without p53 mutation in a 64 year-old man who suffered from the lymphoblastic blast phase of CML.
Blast Crisis ; Genes, p53 ; Genes, ras ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; Point Mutation ; Stress, Psychological

OBJECTIVEThe aim of this review was to assess RNA interference (RNAi) and its possibility as a potential and powerful tool to develop highly specific double-stranded RNA (dsRNA) or small interfering RNA (siRNA) based gene-silencing therapeutics.

DATA SOURCESThe data used in this review were obtained from the current RNAi-related research reports.

STUDY SELECTIONdsRNA-mediated RNAi has recently emerged as a powerful reverse genetic tool to silence gene expression in multiple organisms. The discovery that synthetic duplexes of 21 nucleotides siRNAs trigger gene-specific silencing in mammalian cells has further expanded the utility of RNAi in to the mammalian system.

DATA EXTRACTIONThe currently published papers reporting the discovery and mechanism of RNAi phenomena and application of RNAi on gene function in mammalian cells were included.

DATA SYNTHESISSince the recent development of RNAi technology in the mammalian system, investigators have used RNAi to elucidate gene function, and to develop gene-based therapeutics by delivery exogenous siRNA or siRNA expressing vector. The general and sequence-specific inhibitory effects of RNAi that will be selective, long-term, and systemic to modulate gene targets mentioned in similar reports have caused much concern about its effectiveness in mammals and its eventual use as a therapeutic mordality.

CONCLUSIONSIt is certain that the ability of RNAi in mammals to silence specific genes, either when transfected directly as siRNAs or when generated from DNA vectors, will undoubtedly accelerate the study of gene function and might also be used as a potentially useful method to develop highly gene-specific therapeutic methods. It is also expected that RNAi might one day be used to treat human diseases.

Animals ; Antigens, Neoplasm ; Gene Silencing ; Genes, abl ; Genetic Therapy ; Humans ; Neoplasm Proteins ; genetics ; RNA Interference

In order to evaluate relapse predication ability of STR-PCR combining with qualitative RT-PCR for the bar/abl transcripts to the patient with chronic myeloid leukemia (CML) fulfilled allogeneic stem cell transplantation (allo-HSCT), 24 patients with CML after allo-HSCT were dynamically investigated for MRD, quantitative 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 detected by nested RT-PCR. The results showed that persistent full donor chimerism (DC >/= 95%) was associated with an absence of MRD. All patients with stable MC (90% abl negative had a probability of long-term survival with molecular remission, however the result of bcr/abl positivity was not always associated with leukemia relapse, only the patient with decreasing values of donor chimerism as well as bcr/abl positive proved to be in a higher risk of relapse or graft failure. Decrease of donor chimerism in correlation with MRD positive was detected in 5 patients. Three out of five patients had been proved to have a molecular relapse, one out of five patients had developed to cytogenetic relapse and another patient experienced graft failure. 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 MRD detection in CML and can identify these high risk patients with molecular or cytogenetic relapse after allo-HSCT.
Genes, abl ; Hematopoietic Stem Cell Transplantation ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; diagnosis ; therapy ; Neoplasm, Residual ; Polymerase Chain Reaction ; methods ; Transplantation, Homologous

OBJECTIVETo investigate the effect of dihydroartemisinin (DHA) on the BCR/ABL fusion gene in leukemia K562 cell.

METHODSK562 cells were cultured in vitro. The rate of proliferation inhibition of cells treated with various concentrations of DHA were determined by using [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) method. Expression of BCR/ABL fusion gene was analyzed by reverse transcription(RT-PCR) before and after DHA treatment. Apoptosis of K562 cells was detected by flow cytometry.

RESULTSThe growth of K562 cells was inhibited when the concentrations of DHA were 10-160 umol/L. With the added dose of DHA, the growth inhibition was remarkable, with the rate of inhibition risen from 52.76% to 94.65%. The expression of BCR/ABL fusion gene, as detected by RT-PCR after incubating the K562 cells with 20 umol/L DHA, measured as ΔCt = 4.45 ± 0.25 after 12 h and ΔCt = 5.23 ± 0.21 after 24 h, which was significantly lower compared with that of the control ( ΔCt = 4.23 ± 0.21, P < 0.05).

CONCLUSIONDHA can inhibit the proliferation of leukemia K562 cells and facilitate the induction of apoptosis by downregulating the expression of BCR/ABL fusion gene.

Artemisinins ; pharmacology ; Fusion Proteins, bcr-abl ; biosynthesis ; genetics ; Gene Expression ; drug effects ; Genes, abl ; drug effects ; Humans ; K562 Cells ; Leukemia ; genetics ; Tumor Cells, Cultured

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

To investigate the relationship between the single nucleotide polymorphism (SNPs) of the bcr and abl gene and chronic myelogeous leukemia (CML), the 9 sequence-tagged sites (STS) in bcr and abl gene were screened by DNA pooling and denaturing high performance liquid chromatography (dHPLC), and the results were varified by sequencing. The results showed that the polymorphism sites were detected in 4 out of the 9 STS fragments and there were 3 bases different from the reference sequence found in 3 fragments. In conclusion, the novel SNP in U07000 fragment shows significantly different frequencies between CML and controled people.
Chromatography, High Pressure Liquid ; methods ; Fusion Proteins, bcr-abl ; genetics ; Genes, abl ; genetics ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; Polymorphism, Single Nucleotide ; Proto-Oncogene Proteins c-bcr ; genetics ; Sequence Analysis, DNA ; Sequence Tagged Sites

This study was aimed to detect the changes of bcr/able gene level in ph+ CML patients at different stages after allo-HSCT by real-time quantitative PCR and to evaluate the significance of this detection. The serial detection of bcr/abl fusion gene levels in 21 cases of CML treated with allo-HSCT was performed by RQ-PCR. The results showed that the bcr/able fusion gene could not be detected in 7 out 21 CML cases with positive fusion gene after allo-HSCT, while the bcr/abl fusion gene of different levels could be detected in 14 cases within 1-6 months. Dynamic detection indicated that the bcr/abl fusion gene levels in 9 cases were lower with relative value 0.0074%-0.088% and then could not be detected within 3-7 months after allo-HSCT. The bcr/abl fusion gene levels in 5 cases diagnosed as molecular relapse were between 0.077%-75%. The bcr/abl fusion gene levels in 1 out of 5 cases were 0.95%, 1.5%, and 0.16% in month 1, 2 and 3, respectively, and turned to negative in the month 4 without any treatment after allo-HSCT. 2 cases received the donor peripheral blood stem cell infusion, and then their bcr/abl mRNA levels could not be detected in bone marrow. Another 2 cases developed to the hematologic relapse, 1 out of 2 cases reached CR again after infusion of donor peripheral blood stem cells and chemotherapy, the other one died. It is concluded that serial quantifications of bcr/abl mRNA levels by RQ-PCR are reliable and can be used to detect the MRD, to monitor the outcome and to predict the relapse.
Adolescent ; Adult ; Female ; Fusion Proteins, bcr-abl ; genetics ; Genes, abl ; Hematopoietic Stem Cell Transplantation ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; surgery ; Male ; Middle Aged ; Reverse Transcriptase Polymerase Chain Reaction ; Young Adult