Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chromosomal translocation within B and T cell malignancies has proven a rich source for proto-oncogenes. The obligate DNA breaks within immunoglobulin (Ig) and T cell receptor (TCR) loci are frequently the sites of recurrent translocations. Burkitt's lymphoma established the paradigm by introducing the myc oncogene from chromosome segment 8q24 into the Ig heavy chain gene locus at 14q32. Molecular cloning of an aberrant Ig rearrangement in follicular lymphoma revealed Bcl-2. Bcl-2 constitutes the first member of a new category of oncogenes: regulators of programmed cell death. Bcl-2 blocks apoptosis and maintains long-term immune responsiveness including B-cell memory. The PRAD1 gene of parathyroid adenomas appears to be the elusive Bcl-1 gene of t(11;14)(q13;q32) bearing lymphomas. It proves to be a novel G1 cyclin. Acute lymphoblastic leukemias (ALL) pre-B phenotype produce a E2A/PBX fusion protein that possesses the leucine zipper of E2A with the homeodomain of PBX. Two molecular forms of the BCR/ABL fusion protein are produced by the Philadelphia chromosome. A deregulated p210 tyrosine kinase is found in chronic myelogenous leukemia, while a p190 form predominates in Ph+ ALL. In contrast, T-cell ALLs introduce a potpourri of genes into their T cell receptor loci. However, a common theme is emerging. These oncogenes (Ttg1, Ttg2, SCL, LylI, H0X11) all belong to classic families of transcription factors, possessing LIM domains, helix-loop-helix motifs, or homeodomains. Provocatively, these transcription factors are normally intended for lineages other than T cells. These genes have widened the horizons of both oncogenesis and normal development.
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PMID:Chromosomal translocations in lymphoid malignancies reveal novel proto-oncogenes. 159 Oct 3

hLH-2, a transcription factor that contains double cysteine rich regions (LIM motifs) and a homeobox (Hox) DNA-binding domain shows aberrant high expression in all cases of chronic myelogenous leukemia (CML). This gene has been mapped to the chromosome 9q33-34.1, the same region as the reciprocal translocation that creates the breakpoint cluster region (BCR)-ABL chimera of the Philadelphia chromosome (Ph'). To investigate the possible involvement between the BCR-ABL fusion gene and hLH-2 in the pathogenesis of CML, an hLH-2-negative CML cell line, JK-1 that carries double Ph' chromosomes, was examined. Like other CML cells, high BCR-ABL fusion mRNA levels are expressed, but no transcript of hLH-2 was detected in JK-1 cells as determined by reverse transcriptase-polymerase chain reaction (RT-PCR). Compared with the CML cell line, K-562, an additional rearrangement of the BCR gene was observed in JK-1 as determined by Southern blot hybridization; however, the hLH-2 gene was normal. These findings raise interesting questions about the possible roles of either the abnormal BCR gene or other genetic events such as the complex chromosomal abnormalities that result in hLH-2 being turned off in JK-1 cells.
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PMID:A structurally abnormal breakpoint cluster region gene in a transcription factor, hLH-2-negative human leukemia cell line. 760 May 33

The LH2 gene encodes a putative transcription factor containing two N-terminal LIM and one C-terminal HOX domains. The LH2 locus was mapped to 9q33-34.1, centromeric to the ABL gene. In a recent report, it was suggested that high levels of LH2 expression are consistently observed in chronic myeloid leukemia (CML) patients, whereas no transcription is detected in normal individuals. This led to the hypothesis that aberrant expression of LH2 may represent an additional mechanism for malignant cell proliferation in CML. We have studied the expression of LH2 in leucocytes from patients with CML or with other chronic myeloproliferative disorders (CMD), and from normal individuals, using an optimised reverse-transcription and polymerase chain reaction (PCR) technique. Twenty-seven out of 29 cDNA samples from normal individuals (93%), 49 out of 51 samples from CML patients (96%) and 20 out of 20 from Philadelphia chromosome-negative CMD showed evidence of LH2 expression. Similarly, LH2 transcription was also detected in leucocytes from CML patients in complete cytogenetic remission after treatment with interferon-alpha. Furthermore, all 36 EBV-induced lymphoblastoid cell lines established from six chronic phase CML patients showed unequivocal LH2 expression, regardless of the BCR-ABL status of the line (9 BCR-ABL positive, 27 BCR-ABL negative). We conclude that LH2 expression is not confined to CML cells, and that the t(9;22)(q34;qll) does not promote 'de novo' transcriptional activation of this gene.
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PMID:Expression of the LH2 gene in chronic myeloid leukaemia cells. 868 90

DNA methylation plays an important role in gene regulation. A human LIM-HOX gene, namely hLH-2, was highly expressed in chronic myelogenous leukemia (CML) and located on chromosome 9q33-34.1, in the same region as the reciprocal translocation that creates the Bcr-Abl chimera of Philadelphia chromosome (H.-K. Wu et al., 1996, Oncogene 12, 1205-1212). To elucidate the mechanism of hLH-2 transcriptional activation, we studied the methylation status of hLH-2 in normal bone marrow and CML cells. When blots containing genomic DNA digested with Hpa II or Msp I were hybridized with full-length cDNA probe, it was discovered that hLH-2 was methylated in normal bone marrow cells in which hLH-2 was not expressed; in contrast, both alleles of the hLH-2 locus in CML cells were heavily hypomethylated. Furthermore, using a sensitive RT-PCR technique, we examined the expression of LH-2 in mouse x human hybrids and a wide array of mouse cell lines containing Abl or Bcr-Abl, and we failed to identify a consistent expression pattern in the cell lines tested. These results suggest that the transcriptional activation of hLH-2 in CML is likely due to a cis-acting effect, but not a trans-acting effect, of the Bcr-Abl fusion protein. Because hypomethylated genes generally are transcribed more efficiently than hypermethylated genes, the high level of hLH-2 mRNA in CML cells probably is a consequence of the low level of methylation of the gene in the leukemic cells.
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PMID:Transcriptional activation of human LIM-HOX gene, hLH-2, in chronic myelogenous leukemia is due to a cis-acting effect of Bcr-Abl. 916 38

DNA methylation plays an important role in gene regulation. A human LIM-HOX gene, namely hLH-2, was highly expressed in chronic myelogenous leukemia (CML) and located on chromosome 9q33-34.1, in the same region as the reciprocal translocation that creates the Bcr-Abl chimera of Philadelphia chromosome [Wu et al. (1996) Oncogene 12, 1205]. To elucidate the mechanism of hLH-2 transcriptional activation, we studied the methylation status of hLH-2 in normal bone marrow and CML cells. When blots containing genomic DNA digested with Hpa II or Msp I were hybridized with full-length cDNA probe, it was discovered that hLH-2 was methylated in normal bone marrow cells in which hLH-2 was not expressed; in contrast, both alleles of hLH-2 locus in CML cells were heavily hypomethylated. Furthermore, using the sensitive RT-PCR technique, we examined the expression of LH-2 in mouse x human hybrids and a wide array of mouse cell lines containing Abl or Bcr-Abl and failed to identify a consistent expression pattern in the cell lines tested. These results suggest that the transcriptional activation of hLH-2 in CML is likely due to a cis-acting effect, but not a trans-acting effect of the Bcr-Abl fusion protein. Because hypomethylated genes generally are transcribed more efficiently than hypermethylated genes, the high level of hLH-2 mRNA in CML cells probably is a consequence of the low level of methylation of the gene in the leukemic cells.
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PMID:Transcriptional activation of human LIM-HOX gene hLH-2 in chronic myelogenous leukemia is due to a cis-acting effect of Bcr-Abl. 917 86

We have identified a putative transcription factor, designated hLim-1, from human fetal brain using degenerate polymerase chain reaction (PCR) and cDNA library screening. The deduced open reading frame, derived from sequencing a 3.0-kb hLim-1 cDNA, encodes a protein of 384 amino acids with two cysteine-rich LIM domains and one homeobox (HOX) DNA-binding domain. The nucleotide sequence of hLim-1 cDNA is 87% identical to mouse Lim-1 and the predicted amino acid sequence is greater than 97% conserved. Expression patterns of hLim-1 were evaluated by Northern analysis and reverse transcription (RT)-PCR coupled with Southern blotting. HLim-1 expression was observed in human brain, thymus, and tonsillar tissue. Expression of hLim-1 was also observed in 58% of acute myelogenous leukemia (AML) cell lines and in four of five primary samples from patients with chronic myeloid leukemia (CML) in myeloid blast transformation. The gene encoding hLim-1 was mapped using fluorescence in situ hybridization (FISH) to human chromosome 11p12-13. The expression pattern and structural characteristics of the hLim-1 gene suggest that it encodes a transcriptional regulatory protein involved in the control of differentiation and development of neural and lymphoid cells. Its expression in CML in blast crisis suggests that it may be involved with progression in this disease; a prospective study is required to confirm this.
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PMID:Cloning, expression, and chromosomal localization to 11p12-13 of a human LIM/HOMEOBOX gene, hLim-1. 921 61

Chromosomal aberrations observed in addition to the Philadelphia chromosome in chronic myelogenous leukemia (CML) are likely to be involved in disease progression to the blast crisis. We describe here a t(1;14)(q25;q32) as an additional chromosomal aberration in a patient with CML in biphenotypic blast crisis. By use of long-distance inverse polymerase chain reaction (PCR), we cloned the chromosomal breakpoint and revealed that the immunoglobulin heavy chain gene is fused near its Emu enhancer region to the 5' region of the LHX4 LIM-homeobox gene, whose expression is restricted to the central nervous system. By use of quantitative real-time reverse-transcription PCR, we found that the LHX4 mRNA is expressed at high levels in the patient's leukemic cells and in an acute lymphoblastic leukemia (ALL) cell line. The aberrant expression of the LHX4 gene by the t(1;14)(q25;q32) has very recently been reported in a case of ALL, thus, representing a rare, but recurrent genetic abnormality of possible importance in leukemogenesis.
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PMID:Aberrant expression of the LHX4 LIM-homeobox gene caused by t(1;14)(q25;q32) in chronic myelogenous leukemia in biphenotypic blast crisis. 1450 3

Chronic myelogenous leukemia (CML) is a hematological malignancy that is characteristic by as expansion of myeloid cells and their premature release into the circulation. The molecular cause of CML is the fusion oncoprotein Bcr-Abl whose constitutive tyrosine-kinase (TK) activity maintains enhanced signaling through multiple signal transduction pathways and confers proliferative and survival advantage to CML cells. These effects can be largely suppressed by TK inhibitor Imatinib mesylate, currently the leading drug in CML treatment. However, Bcr-Abl contains also additional functional domains, in particular a DBL homology (DH) domain with guanine-exchange function (GEF) which can activate small GTPases of Rho family and a Src-homology3 (SH3) domain which recruits other proteins with GEF activity. Bcr-Abl affects among others the RhoA/ROCK/LIM/cofilin pathway that regulates the actin cytoskeleton assembly and thereby the cellular adhesion and migration. This review deals in detail with the known points of interference between Bcr-Abl and Rho kinase pathways and with the effects of Imatinib mesylate on Rho signaling and cell adhesion to the extracellular matrix (ECM) components. The potential protein targets related to Bcr-Abl non-kinase activity are discussed.
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PMID:Rho-signaling pathways in chronic myelogenous leukemia. 1907 36

Cancer-stem-cell theory states that most, if not all, cancers arise from a stem/uncommitted cell. This theory revolutionised our view to reflect that cancer consists of a hierarchy of cells that mimic normal cell development. Elegant studies of twins who both developed acute lymphoblastic leukaemia in childhood revealed that at least two genomic insults are required for cancer to develop. These 'hits' do not appear to confer a growth advantage to cancer cells, nor do cancer cells appear to be better equipped to survive than normal cells. Cancer cells created by investigators by introducing specific genomic insults generally belong to one cell lineage. For example, transgenic mice in which the LIM-only 2 (LMO2,associated with human acute T-lymphoblastic leukaemia) and BCR-ABLp210 (associated with human chronic myeloid leukaemia) oncogenes were active solely within the haematopoietic stem-cell compartment developed T-lymphocyte and neutrophil lineage-restricted leukaemia, respectively. This recapitulated the human form of these diseases. This 'hardwiring' of lineage affiliation, either throughout leukaemic stem cell development or at a particular stage, is different to the behaviour of normal haematopoietic stem cells. While normal cells directly commit to a developmental pathway, they also remain versatile and can develop into a terminally differentiated cell that is not part of the initial lineage. Many cancer stem cells do not have this versatility, and this is an essential difference between normal and cancer stem cells. In this report, we review findings that support this notion.
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PMID:Are Leukaemic Stem Cells Restricted to a Single Cell Lineage? 3186 91