The c-Abl nonreceptor tyrosine kinase is activated in the cellular responses to genotoxic, oxidative and other forms of stress. Using tagged forms of c-Abl, the present studies demonstrate that c-Abl forms homodimers in cells. The results show that the c-Abl N-terminal regions interact with the corresponding C-terminal regions of both partners in the dimmer. Specifically, the c-Abl SH3 domain binds to a proline-rich motif at amino acids 958-982 in the c-Abl C-terminal region. Deletion of the proline-rich motif disrupts dimmer formation. These findings provide the first evidence that c-Abl forms homodimers and indicate that homodimerization can contribute to the regulation of c-Abl activity.
Humans ; Protein Multimerization ; Proto-Oncogene Proteins c-abl ; genetics ; metabolism ; src Homology Domains

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

Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is a subtype of B-lineage ALL (B-ALL) that displays a gene expression profile (GEP) similar to Philadelphia chromosome-positive ALL (PhALL). It has a diverse range of genetic alterations that activate cytokine receptor genes and kinase signaling pathways, frequently accompanied by abnormal transcription factors related to lymphatic development. Children with Ph-like ALL account for 15% of children with high-risk B-ALL. It has adverse clinical features and a poor prognosis. Tyrosine kinase inhibitors combined with chemotherapy can significantly improve the prognosis of children with PhALL, suggesting that targeted therapy based on the molecular cytogenetic abnormalities of Ph-like ALL has good research prospects. This paper expounds the genetic alterations, pathogenesis, clinical features, diagnostic measures, and potential therapeutic approaches of Ph-like childhood ALL based on recent research progress in Ph-like ALL.
Humans ; Janus Kinase 2 ; genetics ; PAX5 Transcription Factor ; genetics ; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma ; diagnosis ; drug therapy ; genetics ; Proto-Oncogene Proteins c-abl ; genetics

This study was aimed to investigate the effect of SU11248 on proliferation and apoptosis of leukemia cell line K562 in vitro and its mechanism. The inhibitory effect of 3.2 µg/ml SU11248 on K562 proliferation was tested by MTT assay. The ability of SU11248 to induce apoptosis of K562 cells was examined by TUNEL and DNA ladder. The expression of C-MYC, hTERT and BCR-ABL mRNA in K562 cells was detected by RT-PCR. The protein expression of Akt and p-Akt in K562 cells was detected by Western blot. The results showed that the proliferation of K562 cells was obviously inhibited by 3.2 µg/ml SU11248 in a time-dependent manner. SU11248 could induce K562 cells apoptosis in dose-and time-dependent manner. The mRNA expression of C-MYC, hTERT and BCR-ABL was reduced significantly by SU11248 in a time-dependent manner (P < 0.05). Western blot detection showed that the expression of p-Akt protein in K562 cells decreased in dose-and time-dependent manner after SU11248 treatment, but the expression of Akt was not significantly changed. It is concluded that SU11248 can inhibit the growth of K562 cells efficiently through inducing apoptosis, its mechanism may be closely relate with the expression down-regulation of C-MYC, hTERT, BCR-ABL and the inhibition of Akt phosphorylation.
Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Fusion Proteins, bcr-abl ; metabolism ; Humans ; Indoles ; pharmacology ; K562 Cells ; Proto-Oncogene Proteins c-akt ; metabolism ; Proto-Oncogene Proteins c-myc ; metabolism ; Pyrroles ; pharmacology ; RNA, Messenger ; genetics ; Telomerase ; metabolism

OBJECTIVETo compare the signal patterns of dual color extra-signal BCR/ABL probe (ES-FISH) and dual color dual fusion BCR/ABL probe (D-FISH) in the fluorescence in situ hybridization (FISH) detection of Ph-positive leukemia, and to explore their diagnostic value.

METHODSES-FISH probe and D-FISH probe were used, respectively, to detect the BCR/ABL fusion gene in 74 cases with typical t(9;22)(q34;q11) and 37 cases with variant t(9;22)(q34;q11) translocation or complex karyotypic abnormalities containing Ph translocation.

RESULTSThe BCR/ABL fusion gene in all cases with typical t(9;22)(q34;q11) could be detected by both FISH probes. D-FISH had a signal pattern of 1O1G2F, while ES-FISH showed a signal pattern of 2O1G1F. ES-FISH enables the minor breakpoint cluster region to be identified in 9 cases (12.2% ) of Ph-positive leukemia, whereas D-FISH could not differentiate the minor breakpoint cluster region from major breakpoint cluster region. D-FISH could distinguish simple ABL gene deletion from simultaneous deletion of the ABL and BCR genes in 8 cases (10.8%) of Ph-positive leukemia patients, but ES-FISH could not. For variant Ph translocation or complex karyotypic abnormalities containing Ph translocation, each FISH probe showed four or six types of signal pattern, most of which were atypical. The exact interpretation was dependent on conventional karyotypic analysis and FISH on metaphases.

CONCLUSIONES-FISH and D-FISH probes displayed different signal patterns in Ph-positive leukemia due to their differences in size and covered regions. ES-FISH and D-FISH probes may be selected as better probe for Ph-positive acute lymphocytic leukemia and Ph-positive chronic myeloid leukemia, respectively. When imatinib was used for treatment, there was no preference between ES-FISH and D-FISH probe, because major breakpoint cluster region, minor breakpoint cluster region and partial sequence deletion of derivative chromosome 9, would not affect the prognosis of Ph-positive leukemia. However, considering that ES-FISH probe has a better cost-performance than D-FISH probe does, it is recommended as first choice.

Case-Control Studies ; Chromosomes, Human, Pair 9 ; genetics ; Humans ; In Situ Hybridization, Fluorescence ; methods ; Karyotyping ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; diagnosis ; genetics ; Proto-Oncogene Proteins c-bcr ; genetics

The study was purposed to analyze the relationship between the content of T-cell receptor excision DNA circles (TREC) and bcr-abl mRNA levels in CML patients and to evaluate the prognostic significance of recent thymic output function detection in patients with chronic myelogenous leukemia (CML). Quantitative detection of TREC and bcr-abl fusion gene transcripts in peripheral blood from 15 CML patients were preformed by real-time PCR. The change of bcr-abl levels in 6 patients was followed-up for two years. The results showed that there was no significant correlation between TREC and bcr-abl mRNA levels in peripheral blood from CML patients for the first attack. Patients who had higher TREC at diagnosis had a larger reduction of bcr-abl after 2 years of follow-up. While out of 2 patients who underwent haemopoietic stem cell transplantation (HSCT), one patient with higher level of TREC before transplantation was confirmed to express undetectable level of TREC by three consecutive detections after transplantation, other one patient was identified to express low level of bcr-abl. It is concluded that high thymic output function in CML patients can be beneficial for killing the residual CML cells.
Adolescent ; Adult ; Aged ; Female ; Fusion Proteins, bcr-abl ; biosynthesis ; genetics ; Gene Rearrangement ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; immunology ; Male ; Middle Aged ; Proto-Oncogene Proteins c-abl ; biosynthesis ; genetics ; Proto-Oncogene Proteins c-bcr ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Receptors, Antigen, T-Cell ; analysis ; immunology ; T-Lymphocytes ; chemistry ; immunology ; Thymus Gland ; immunology

OBJECTIVETo study the effects of anti-ABL tyrosine kinase intrabody on the growth of human chronic myelogenous leukemia (CML) cells in nude mice.

METHODSA recombinant retroviral vector MSCV-ibE-IRES-eGFP was constructed to express intracellular single-chain antibody (intrabody) against ABL tyrosine kinase domain in CML cells. K562 cells were transduced with the retrovirus, eGFP+ cells were then selected by fluorescence-activated cell sorting (FACS). The intrabody mRNA expression was determined by reverse transcription (RT)-polymerase chain reaction (PCR). BCR/ABL and c-ABL protein tyrosine kinase (PTK) activity in the cells was examined. Transduced cells and control group K562 cells were transplanted into nude mice respectively and the tumor sizes were dynamically observed.

RESULTSK562-ibE cell was obtained. Expression of the BCR/ABL and c-ABL protein tyrosine kinase activity of harvested K562-ibE cells were markedly inhibited. At 14, 21 and 28 days after cell injection, the tumor volumes of experimental mice were obviously smaller than that of control mice, about one half of the control groups (P < 0.05).

CONCLUSIONThe growth of K562-ibE cells was significantly inhibited in vivo. It is possible that inhibition of the BCR/ABL protein tyrosine kinase activity by the intrabody blocked BCR/ABL signal transduction pathway, promoted apoptosis and reduced tumorigenicity of K562 cells in vivo.

Animals ; Antibodies ; genetics ; Apoptosis ; Cell Division ; Fusion Proteins, bcr-abl ; biosynthesis ; genetics ; immunology ; Genetic Vectors ; Humans ; K562 Cells ; Mice ; Mice, Nude ; Neoplasm Transplantation ; Protein-Tyrosine Kinases ; immunology ; metabolism ; Proto-Oncogene Proteins c-abl ; genetics ; immunology ; Retroviridae ; genetics

This study was aimed to explore the single nucleotide polymorphism (SNPs) of breakpoint cluster region of bcr gene in Chinese people and the relationship between SNPs and chronic myelogenous leukemia (CML). A 3.12 kb region spanning from exon 13 to exon 15 in the bcr region were screened by DNA pooling and denaturing high performance liquid chromatography (dHPLC), and the results were verified by sequencing. The results indicated that 6 novel SNP sites and 2 bases different from reference sequence were confirmed in the region studied, and the frequency of 6 novel SNP sites in studied population was obtained, one SNP of which was found in exon 13 and caused a nonsynonymous mutation. The gene frequencies of novel SNPs had no significant difference between CML and control people. It is concluded that sequence polymorphisms in the major breakpoint cluster region of bcr gene are found, most of which are SNPs, No relationship can be confirmed between SNPs and CML disease.
Base Sequence ; Chromosome Breakage ; Fusion Proteins, bcr-abl ; genetics ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; Molecular Sequence Data ; Polymorphism, Single Nucleotide ; Proto-Oncogene Proteins c-bcr ; genetics

The aim of this study was to evaluate the value of CD117/CD11b phenotypic analysis to diagnosis and prognosis of acute promyelocytic leukemia (APL). Three- or four-color flow cytometry with a series of 22 monoclonal antibodies and CD45/Side Scatter (SSC) gating strategy were used to identify immunophenotypic characteristics of APL as compared to CML in chronic phase (CML-CP). PML/RAR alpha fusion gene was detected by using reverse-transcription polymerase chain reaction (RT-PCR) technique. The results showed that MPO, CD13 and CD33 were almost expressed in all patients with APL and CML-CP whereas HLA-DR and CD34, the hematopoietic progenitor cell markers, were rarely expressed. The positive rate of CD15 in APL was significantly lower than those in CML-CP (P < 0.01). CD117 was positive in 78.3% of the APL cases and in none of the cases of CML-CP. On the other hand, CD11b was almost positive in all cases of CML-CP, but only 16.9% of the APL cases were found positive for this antigen. The CD117+ CD11b- phenotype was present in 72.3% of APL cases while none of cases with CML-CP with this phenotype. Almost all of the cases with CML-CP had the phenotype of CD117- CD11b+. CD117- CD11b+ phenotype was detected in all patients recovering from APL with CD117+ CD11b- phenotype at diagnosis and after treatment with all-trans-retinoic acid (ARTA) for 2 months. PML/RAR alpha fusion gene was positive in 80.6% (25/31) of the APL cases, of which, 64% of the cases belonged to the type L while only 36% of the cases were showed type S for this fusion gene. The positive rates of CD117 were 87.5%, 44.4% and 33.3% in type L group, S group and negative group respectively. It is concluded that analysis of both CD117 and CD11b phenotype may be helpful to the diagnosis, therapy and prognosis of APL in children and adults and to differentiation of APL from recovering benign myeloid proliferation.
Adolescent ; Adult ; CD11b Antigen ; analysis ; Child ; Female ; Humans ; Immunophenotyping ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; diagnosis ; genetics ; immunology ; Leukemia, Promyelocytic, Acute ; diagnosis ; genetics ; immunology ; Male ; Oncogene Proteins, Fusion ; genetics ; Prognosis ; Proto-Oncogene Proteins c-kit ; analysis

Chronic myelogenous leukemia (CML) is a myeloproliferative disorder from hematopoietic stem cell disorder characterized by the consecutive expression of bcr-abl gene, and the translation product of which has enhanced tyrosine kinase activity and can activate a series of downstream signal transduction proteins and results in the occurence of CML. Although the application of imatinib (IM) makes nearly all patients with CML in chronic phase achieve a complete hematologic remission, and 90%of those treated in the early chronic phase achieve a complete cytogenetic remission, but the development of resistance to IM in the course of treatment and even in the beginning of the treatment forced people to develop new agents and to combine the new agents with IM in order to achieve better therapeutic result. This article reviews the experimental advances of targeted therapeutics in CML recent years.
Antineoplastic Agents ; administration & dosage ; Benzamides ; Drug Delivery Systems ; Humans ; Imatinib Mesylate ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; drug therapy ; Piperazines ; administration & dosage ; Protein Kinase Inhibitors ; administration & dosage ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Proto-Oncogene Proteins c-abl ; biosynthesis ; genetics ; Proto-Oncogene Proteins c-bcr ; biosynthesis ; genetics ; Pyrimidines ; administration & dosage