Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel DNA-binding activity, hereafter referred to as MECA, is induced upon transformation of rat embryo fibroblasts by the collaborative action of the oncogenes myc and ras. MECA is targeted to the enhancer "core" element of the Moloney Murine Leukemia Virus LTR. Its binding site can direct transcription from a heterologous promoter and EJras, but not c-myc, potentiates the transcriptional activity. A two point mutation within the enhancer "core" abolishes both DNA-binding by MECA and transcriptional activity. MECA may mediate some of the transforming effects of ras, and thus belongs in the family of transformation-specific DNA-binding activities with members such as AP-1, PEA3 and NF-kB.
 ...
PMID:An enhancer "core" DNA-binding and transcriptional activity is induced upon transformation of rat embryo fibroblasts. 158 May 45

The human factor-dependent leukemia cell line UCSD/AML1 contains the t(3;3) (q21;q26) characteristic of the syndrome of acute leukemia with high platelets. The human homologue of the murine leukemia oncogene evi-1 was recently localized to chromosome 3q24-3q28 and transcription of evi-1 is a frequent event in mouse-retrovirus-induced leukemias (17). To determine whether translocations near human 3q24 might induce similar genetic changes, we examined and compared evi-1 and c-myc expression and regulation in UCSD/AML1 cells. Steady-state evi-1 transcripts were detected in UCSD/AML1 and murine leukemia M1 cells, but were not present in HL60 or Namalwa human leukemia cells. Transcription assays showed the evi-1 gene was actively transcribed in UCSD/AML1, but not HL60 nuclei. Evi-1 transcript sizes and half-life were similar in UCSD/AML1 and human HEC-1B carcinoma cells which express evi-1 transcripts, but do not have abnormalities involving chromosome 3. An alternative splice site detected by polymerase chain reaction was present in transcripts from both cell lines. Regulation of evi-1 RNA in UCSD/AML1 cells was similar to that of actin transcripts in response to cycloheximide or phorbol-ester-induced macrophage differentiation. After withdrawal of granulocyte/macrophage colony-stimulating factor (GM-CSF), evi-1, actin, and histone H3 transcripts declined in concert with exit from the cell cycle. Minor differences in rates of recovery were noted for these three genes after GM-CSF restimulation. In contrast, c-myc was expressed at high levels in UCSD/AML1 cells and showed evidence for specific regulation in response to cycloheximide, phorbol ester, and GM-CSF withdrawal and restimulation. These studies suggest the 3q translocation in UCSD/AML1 cells is associated with evi-1 transcription and expression of a potential transforming gene. In contrast to c-myc, evi-1 expression is minimally altered by biologically active chemicals or growth factor stimulation.
Leukemia 1992 May
PMID:Expression and regulation of the evi-1 gene in the human factor-dependent leukemia cell line, UCSD/AML1. 159 10

A 59-year-old man was admitted because of generalized lymphadenopathy with fever and vomiting. His peripheral blood showed leukocytosis with a WBC of 93,500/microliters, and the bone marrow picture revealed a predominance of blast cells. The blasts were negative for peroxidase, alpha-naphthyl butyrate esterase and PAS, and had the phenotype of CD 7, 13 and 33 positive. A diagnosis of AML M0 was made, based on the criteria of the NCI-sponsored workshop in 1988. His initial status had been compromised by acute renal failure which necessitated hemodialysis. He responded partially to chemotherapy consisting of daunorubicin, cytarabine and prednisolone. However leukemia recurred and the patient suffered from various episodes of infection and died six months after admission. The Southern blotting showed the germ line configuration for TCR-beta chain and immunoglobulin heavy chain genes. No messenger RNA was detected for myeloperoxidase, c-myc and c-jun, while c-fms, c-fos and c-myb were expressed on Northern blotting. It is intriguing to detect c-fms and c-fos expression in these poorly differentiated leukemic cells.
 ...
PMID:[A case report of AML M0:CD7, 33 (+) AML M0 case initially presented with cervical lymphadenopathy]. 160 10

Oncostatin M (OM) is a cytokine that shares a structural and functional relationship with interleukin 6, leukemia-inhibitory factor, and granulocyte colony-stimulating factor. In this report, we tested for correlations between immediate-early gene expression and some of the cellular responses elicited by OM. We determined that OM stimulated a rapid and transient elevation of EGR-1, c-jun, and c-myc mRNA in human fibroblasts prior to their proliferation. OM also stimulated a transient induction of these genes in M1 leukemic cells that differentiated into nonreplicating, macrophage-like cells. The expression of c-myc, however, decreased significantly as the cells stopped dividing. Interestingly, OM had no detectable effect on the expression of EGR-1, c-jun, and c-myc during the cell cycle arrest of human A375 melanoma cells. Our results indicate that an early nuclear event associated with OM action is the regulation of immediate-early gene expression. We suggest that the transcription factors encoded by the EGR-1, c-jun, and c-myc genes are utilized in both cell proliferation and differentiation but are not part of the mechanism by which OM inhibits A375 cell growth.
 ...
PMID:Regulation of EGR-1, c-jun, and c-myc gene expression by oncostatin M. 163 13

Chemical inducers of the differentiation are known to cause an early transient decrease in c-myc and c-myb mRNA levels in Friend erythroleukemia cells preceding the down-regulation of c-myc and c-myb expression in the course of irreversible terminal differentiation. We therefore investigated the early effect of the potent differentiation-inducing anthracycline antitumor antibiotic, aclacinomycin A, on the c-myc and c-myb mRNA levels in the Friend cell line, F4-6, using Northern blot analysis. Aclacinomycin A induced a rapid decrease in the levels of c-myc and c-myb transcripts within 0.5-1 h and 2-3 h, respectively. The time course of decline in c-myc and c-myb expression was similar to that observed with dimethylsulfoxide or after transcription blockage brought about by a high concentration of actinomycin D. By 12 to 18 h after aclacinomycin A exposure, the c-myc and c-myb mRNA levels had returned to about pretreatment levels. When the cells were treated with adriamycin, an anthracycline that reduces cell proliferation in F4-6 cells without increasing differentiation, an early decrease in c-myc and c-myb expression was not observed. These results suggest that the transient decrease in c-myc and c-myb mRNA levels in F4-6 cells may be an early differentiation-related biochemical effect of aclacinomycin A.
Leukemia 1992 Aug
PMID:Induction of differentiation in Friend-erythroleukemia cells by aclacinomycin A: early transient decrease in c-myc and c-myb mRNA levels. 164 Jul 36

Human T cell leukemia virus type 1 is the causative agent of adult T cell leukemia. The virus encodes a 40-kDa protein, tax, that is important for the immortalization of T cells. Expression of tax activates several cellular transcription factors, including NF kappa B. We have previously identified two functional NF kappa B binding sites within the murine c-myc gene: upstream regulatory element (URE) and internal regulatory element (IRE). Using transient cotransfection analysis of Jurkat or HeLa cells, we report that tax can transactivate chimeric TK-CAT constructs containing multiple copies of wild-type URE or IRE, but not constructs with mutated versions of these elements. Furthermore, tax induced transcriptional activity of murine and human c-myc promoter-CAT hybrid genes in Jurkat and HeLa cells. A mutated tax expression vector, which fails to activate NF kappa B, was unable to induce either murine or human c-myc-CAT or URE/IRE-TK-CAT constructs. Mutant c-myc gene-CAT constructs, in which the URE and IRE were mutated either singly or in combination by site directed mutagenesis, displayed significantly reduced CAT activation upon cotransfection with a tax expression vector. These results suggest that tax can transactivate the c-myc gene through NF kappa B. The tax-induced stimulation of this oncogene may play a role in T cell immortalization.
 ...
PMID:Transactivation of the c-myc promoter by human T cell leukemia virus type 1 tax is mediated by NF kappa B. 164 14

Amphotropic murine retrovirus 4070A was demonstrated to be highly leukemogenic when inoculated intravenously into adult DBA/2 mice that were undergoing an intense chronic inflammatory response, but was nonleukemogenic in the absence of inflammation. The virus-induced promoonocytic leukemias, designated AMPH-ML, are similar morphologically and in cell surface marker expression to monocytic leukemias, called MML and MF-ML, previously shown to be induced by Moloney murine leukemia virus and MF-3 virus (a recombinant between Friend murine leukemia virus and Moloney murine leukemia virus) and resemble certain mature acute monocytic leukemias in humans (AML subtype M5). Approximately two-thirds of the AMPH-MLs (subgroup I) were demonstrated to have alterations in the 5' end of the c-myb locus, an event which occurs in 100% of MML and MF-ML. Data indicate that proviral insertions in AMPH-ML subgroup I resulted in aberrant c-myb mRNA expression and truncation of its translation product at the amino terminus. Approximately one-third of the AMPH-MLs (subgroup II) had not undergone any DNA rearrangements at the c-myb locus. In addition, their transcripts and protein products were of normal size. These latter leukemias also had not undergone DNA rearrangements in c-myc, although retroviruses expressing myc have previously been shown to induce monocyte-macrophage tumors in mice undergoing a chronic inflammation. That subgroup II leukemias had at least one clonal viral insertion suggests that there may be other sites in the cellular genome that can be activated by insertional mutagenesis in these murine acute monocytic leukemias.
 ...
PMID:Acute myeloid leukemia induction by amphotropic murine retrovirus (4070A): clonal integrations involve c-myb in some but not all leukemias. 164 85

Granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates both the proliferation and functional properties of normal and leukemic myeloid cells via cell surface receptors. The postreceptor mechanisms for these two actions, and the extent to which they represent overlapping biochemical pathways, have not been fully clarified. We have examined the actions of GM-CSF on the expression of c-myc, an early response oncogene associated with the proliferative stimulus of growth factors. GM-CSF reduced the population doubling time of HL-60 leukemia cells from 32 hours to 25 hours, and, at concentrations that were correlated with mitogenicity, induced a rapid twofold increase in the level of c-myc mRNA. Nuclear runoff studies indicated that GM-CSF approximately doubled the transcription rate of c-myc by reversing the transcription attenuation that occurs at the exon 1-intron 1 junction. GM-CSF had no effect on the half-life of c-myc messenger RNA. The biochemical basis for the modulation of c-myc expression by GM-CSF was explored. GM-CSF treatment caused intracellular alkalinization of the cells as measured using the fluorescent probe 2', 7-bis (2-carboxyethyl)-5(and-6) carboxyfluorescein (BCECF). The sodium channel blocker amiloride prevented the GM-CSF-induced change in pH, but did not affect the stimulation of c-myc transcription by GM-CSF. Agents that increase cellular cyclic adenosine monophosphate (cAMP) levels (prostaglandin E2 and cholera toxin) blocked the actions of GM-CSF on c-myc; however, these agents also reduced the basal level of c-myc expression. GM-CSF caused a rapid (5 minutes) and transient decline in cellular cyclic guanosine monophosphate (cGMP) levels, and a slower (30 minutes) and transient decrease in cellular cAMP levels. These observations are consistent with the hypothesis that the declines in cAMP and cGMP are associated with a stimulation of HL-60 proliferation, while previously reported manipulations that elevate cyclic nucleotides are related to an inhibition of HL-60 proliferation and the potentiation of differentiation.
 ...
PMID:Regulation of c-myc expression by granulocyte-macrophage colony-stimulating factor in human leukemia cells. 164 47

We previously described a preleukemic state induced by Moloney murine leukemia virus (Mo-MuLV) characterized by hematopoietic hyperplasia in the spleen. Further experiments suggested that splenic hyperplasia results from inhibitory effects in the bone marrow, leading to compensatory extramedullary hematopoiesis. An enhancer variant of Mo-MuLV, Mo + PyF101 Mo-MuLV, fails to induce preleukemic hyperplasia and has greatly reduced leukemogenicity, indicating the importance of this state to efficient leukemogenesis. An alternative method for induction of preleukemic hyperplasia was sought. Treatment of mice with 89Sr causes specific ablation of bone marrow hematopoiesis and compensatory extramedullary hematopoiesis in spleen and nodes. NIH Swiss mice were inoculated neonatally with Mo + PyF101 Mo-MuLV and treated with 89Sr at 6 weeks of age. Approximately 85% developed lymphoid leukemia with a time course resembling that caused by wild-type Mo-MuLV. In contrast, very few animals treated with Mo + PyF101 Mo-MuLV or 89Sr alone developed disease. In approximately one-third of cases, the Mo + PyF101 Mo-MuLV proviruses were found at common sites for wild-type Mo-MuLV-induced tumors (c-myc, pvt-1, and pim-1), indicating that this virus is capable of performing insertional activation in T-lymphoid cells. These results support the proposal that splenic hyperplasia results from inhibitory effects in the bone marrow. They also indicate that Mo + PyF101 Mo-MuLV is blocked in early and not late events in leukemogenesis.
 ...
PMID:Bone marrow depletion by 89Sr complements a preleukemic defect in a long terminal repeat variant of Moloney murine leukemia virus. 164 40

A new Epstein-Barr virus nuclear antigen (EBNA)-positive B-cell line, designated BALL-2, was spontaneously established from the peripheral blood of a 14-year-old boy with an EBNA-negative B-cell acute lymphoblastic leukemia (B-ALL), L2 in the French-American-British classification. The BALL-2 cell line grew in suspension with or without forming clumps of cells. The cultured cells exhibited lymphoid morphology with indented or lobulated nuclei, prominent nucleoli, and relatively abundant cytoplasm. Immunologic and cytogenetic studies showed that the BALL-2 cell line expressed the B-cell phenotype, CpIg+, SmIg+, CD19+, CD20+, CD38-, Ia+, and had chromosome translocation, t(8;14) (q24;q32). The same phenotypic and chromosome markers were present in original leukemia cells. These results indicated that the cell line was derived from the patient's leukemia cells. Unexpectedly, however, BALL-2 cells were positive for EBNA and EB virus DNA. Gene analysis of the BALL-2 cell line showed biallelic rearrangements in the JH locus. One of the JH rearrangement comigrated with a rearranged c-myc gene, indicating the translocation had occurred between JH and c-myc loci. The t(8;14) abnormality is a known chromosome marker of Burkitt lymphoma and L3 type ALL. Our studies revealed that this translocation and myc gene rearrangement can also be found in L2 type B-ALL.
 ...
PMID:Establishment of a new Epstein-Barr virus nuclear antigen-positive B-cell line, BALL-2, with t(8;14) (q24;q32) chromosome abnormality from B-cell acute lymphoblastic leukemia, L2. 165 Jan 33


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>