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)

The study was aimed to investigate the expression of VEGF mRNA and VEGF protein in HL-60 cells treated with diallyl disulfide (DADS), and to explore the antileukemic mechanism of DADS in respect of VEGF production. Semi-quantitative RT-PCR and ELISA were used to detect the expression of VEGF mRNA and secretion of VEGF protein in HL-60 cell lines treated by DADS respectively. The results showed that the expression of VEGF mRNA and secretion of VEGF protein were found in HL-60 cells. The expression of VEGF mRNA and secretion of VEGF protein in HL-60 cells could be down regulated by treatment with 0.625, 1.25, and 2.5 microg/mL DADS for 48 and 72 hours and the effects had a dose dependent relationship (r > 0.9, P < 0.01). The differences between DADS treated HL-60 cell groups and the control group were statistically significant (P < 0.01), there were also statistically significant differences among three DADS-treated HL-60 cell groups (P < 0.05). It is concluded that DADS effectively inhibits the proliferation of human leukemia cell line HL-60 cells; DADS exerts its antileukemic effects by reduction of the expression of VEGF mRNA and VEGF protein secretion.
 ...
PMID:[Effect of diallyl disulfide on expression and secretion of VEGF in HL-60 leukemic cells]. 1663 82

Deletions at chromosome 12p12-13 are observed in 26-47% of childhood pre-B acute lymphoblastic leukaemia (ALL) cases, suggesting the presence of a tumour suppressor gene (TSG). Accumulating genetic and functional evidence points to ETV6 as being the most probable TSG targeted by the deletions. ETV6 is a ubiquitously expressed transcription factor of the ETS family with very few known targets. To understand its function and to elucidate the impact of its absence in leukaemia, we conducted a study to identify targeted genes. Following the induction of ETV6 expression, global expression was evaluated at different time points. We identified 87 modulated genes, of which 10 (AKR1C1, AKR1C3, IL18, LUM, PHLDA1, PTGER4, PTGS2, SPHK1, TP53 and VEGF) were validated by real-time quantitative reverse transcription-polymerase chain reaction. To assess the significance of the validated candidate genes in leukaemia, their expression patterns were determined, as well as that of ETV6, in pre-B ALL patients. The expression of IL18, LUM, PTGER4, SPHK1 and TP53 was significantly correlated with that of ETV6, further suggesting that ETV6 could regulate the expression of these genes in leukaemia. This work constitutes another step towards the understanding of the functions of ETV6 and the impact of its inactivation in childhood leukaemia.
 ...
PMID:Identification of transcripts modulated by ETV6 expression. 1706 81

In acute myeloid leukemia (AML), autocrine or paracrine activation of receptor tyrosine kinases such as c-kit and FLT3 contributes to proliferation and apoptosis resistance of leukemic blasts. This provided the rationale for a multicenter clinical trial in patients with refractory AML with SU5416, a small molecule kinase inhibitor which blocks phosphorylation of c-kit, FLT3, VEGFR-1, VEGFR-2 (KDR) and VEGFR-3. The levels of VEGF mRNA expression were investigated in peripheral blood leukemic blasts taken from AML patients before and during treatment with SU5416. Rapid down regulation of VEGF was observed in AML blasts from 72% (13 of 18) of patients analysed. Patients initially expressing high VEGF-levels had a stronger downregulation and a higher clinical response rate (mean 865-fold, n = 10, P = 0,01) than patients initially expressing low VEGF-levels (mean four-fold, n = 8). These results suggest that abnormal high VEGF expression is downregulated by SU5416 treatment, and furthermore that decreases in VEGF mRNA levels may provide an early marker of therapeutic response with anti-angiogenic therapy. Additionally, protein expression of STAT5 and AKT was assessed by western blotting in these patient samples, as well as in the leukemia cell line, M-07e, treated in vitro with SU5416 as a model system. In the AML patient samples, parallel downregulation of both STAT5 and AKT was observed in several cases (STAT5 in four of 15; AKT in three of six examined patients). These effects were confirmed with the cell line M-07e after incubation with SU5416 in vitro using concentrations that are achievable in patients. In summary, our data show suppression of the expression of VEGF and key signal transduction intermediates in AML blasts during treatment with SU5416.
 ...
PMID:Downregulation of VEGF-A, STAT5 and AKT in acute myeloid leukemia blasts of patients treated with SU5416. 1716 5

HTLV-1 (human T-cell leukaemia virus type 1) is the causative agent for ATL (adult T-cell leukaemia). HTLV-1 Tax can activate the PI3K (phosphoinositide 3-kinase)/Akt signalling pathway, which is responsible for survival of HTLV-1-infected T-cells. HIFs (hypoxia-inducible factors) are transcriptional regulators that play a central role in the response to hypoxia. Overexpression of HIF-1alpha in many cancers is associated with a poor response to treatment and increased patient mortality. Our objectives in the present study were to investigate whether HIF-1 was activated in HTLV-1-infected T-cells and to elucidate the molecular mechanisms of HIF-1 activation by focusing on the PI3K/Akt signalling pathway. We detected a potent pathway that activated HIF-1 in the HTLV-1-infected T-cells under a normal oxygen concentration. Enhanced HIF-1alpha protein expression and HIF-1 DNA-binding activity were exhibited in HTLV-1-infected T-cell lines. Knockdown of HIF-1alpha by siRNA (small interfering RNA) suppressed the growth and VEGF (vascular endothelial growth factor) expression of the HTLV-1-infected T-cell line. HIF-1 protein accumulation and transcriptional activity were enhanced by Tax, which was inhibited by dominant-negative Akt. Importantly, mutant forms of Tax that are defective in activation of the PI3K/Akt pathway failed to induce HIF-1 transcriptional activity. The PI3K inhibitor LY294002 suppressed HIF-1alpha protein expression, HIF-1 DNA-binding and HIF-1 transcriptional activity in HTLV-1-infected T-cell lines. In primary ATL cells, HIF-1alpha protein levels were strongly correlated with levels of phosphorylated Akt. The results of the present study suggest that PI3K/Akt activation induced by Tax leads to activation of HIF-1. As HIF-1 plays a major role in tumour progression, it may represent a molecular target for the development of novel ATL therapeutics.
 ...
PMID:Activation of hypoxia-inducible factor 1 in human T-cell leukaemia virus type 1-infected cell lines and primary adult T-cell leukaemia cells. 2134 57

Different signaling routes seem to be simultaneously triggered in leukemia, with distinct and overlapping activities. To analyze if altered signals are coordinated and to evaluate their effect on this disease, we have investigated in acute myeloid leukemia samples (AML) the expression and activation status of procoagulant/proangiogenic tissue factor receptor (TF), angiogenic protein VEGF, its cell surface receptor, KDR, and two intracellular proteins involved in their regulation: extracellular regulated kinase (ERK1/2) and nuclear factor kappa-B (NFkappaB). Significantly higher mRNA and protein levels of VEGF, KDR, and TF were found in the AML samples versus controls. Enhanced ERK phosphorylation and NFkappaB activation in most AML samples were also found. In vitro MEK/ERK and NFkappaB-binding activity blockade suppressed the constitutive expression of TF, VEGF, and KDR. Anti-TF antibody treatment significantly suppressed VEGF and KDR expression as well as ERK activation, suggesting that TF expressed by AML cells may be both a regulatory target and a mediator of tumor-associated angiogenesis. Patients showing parallel activation of the studied proteins trended to exhibit higher incidence of fatal outcome. Our results show a coordinated deregulation of cellular receptors, proangiogenic factors, and intracellular pathways in leukemia cells, which may help to design mechanism-based combinations of single transduction-related therapies.
 ...
PMID:Coordinated deregulation of cellular receptors, proangiogenic factors and intracellular pathways in acute myeloid leukaemia. 1757 83

In order to investigate the effects of Na(2)SeO(3) on expression of VEGF in K562/ADR cells, K562 and K562/ADR cells were treated with Na(2)SeO(3) at dose of 5 and 10 micromol/L. The expressions of VEGF in K562 and K562/ADR cells were detected by ELISA before and at the different time point after treatment. The mutiplie of reversion of resistance was detected by MTT method. The results showed that Na(2)SeO(3) at dose of 10 micromol/L could increase the sensitivity of K562/ADR cell to adriamycin, the multiple of reversion was 3.48. The expression levels of VEGF in K562 and K562/ADR cells increased with prolongation of time cultured, and the VEGF expression levels in K562/ADR cells at the different time points were higher than that in K562 cells (P < 0.05); 5 and 10 micromol/L Na(2)SeO(3) did not suppress expression of VEGF in K562 cells at 72 hours (P > 0.05), and the VEGF level in K562 cells at 96 hours decreased without statistical significance; 5 and 10 micromol/L Na(2)SeO(3) acting for 48 hours did not show suppressive effect on expression of VEGF in K562/ADR cells (P > 0.05), 5 micromol/L Na(2)SeO(3) could decrease the expression of VEGF in K562/ADR cell after treatment for 96 hours, while 10 micromol/L Na(2)SeO(3) could significantly decrease the expression of VEGF in K562/ADR cells treated for 72 hours and 96 hours (P < 0.01). It is concluded that VEGF would be involved in the multidrug resistance of leukemia. Na(2)SeO(3) decreasing expression of VEGF in leukemic cells may be one of the mechanisms reversing multidrug resistance.
 ...
PMID:[Effects of Na(2)SeO(3) on expression of VEGF in K562/ADR cells]. 1760 48

Gambogic acid (GA), a xanthone derived from the resin of the Garcinia hanburyi, has been recently demonstrated to bind transferrin receptor and exhibit potential anticancer effects through a signaling mechanism that is not fully understood. Because of the critical role of NF-kappaB signaling pathway, we investigated the effects of GA on NF-kappaB-mediated cellular responses and NF-kappaB-regulated gene products in human leukemia cancer cells. Treatment of cells with GA enhanced apoptosis induced by tumor necrosis factor (TNF) and chemotherapeutic agents, inhibited the expression of gene products involved in antiapoptosis (IAP1 and IAP2, Bcl-2, Bcl-x(L), and TRAF1), proliferation (cyclin D1 and c-Myc), invasion (COX-2 and MMP-9), and angiogenesis (VEGF), all of which are known to be regulated by NF-kappaB. GA suppressed NF-kappaB activation induced by various inflammatory agents and carcinogens and this, accompanied by the inhibition of TAK1/TAB1-mediated IKK activation, inhibited IkappaBalpha phosphorylation and degradation, suppressed p65 phosphorylation and nuclear translocation, and finally abrogated NF-kappaB-dependent reporter gene expression. The NF-kappaB activation induced by TNFR1, TRADD, TRAF2, NIK, TAK1/TAB1, and IKKbeta was also inhibited. The effect of GA mediated through transferrin receptor as down-regulation of the receptor by RNA interference reversed its effects on NF-kappaB and apoptosis. Overall our results demonstrate that GA inhibits NF-kappaB signaling pathway and potentiates apoptosis through its interaction with the transferrin receptor.
 ...
PMID:Gambogic acid, a novel ligand for transferrin receptor, potentiates TNF-induced apoptosis through modulation of the nuclear factor-kappaB signaling pathway. 2364 Sep 97

This study was purposed to explore the tumorigenicity of a novel human monocytic leukemic cell line SHI-1 in nude mice and its mechinism. The tumorigenicity in mice was evaluated in sixteen nude mice subcutaneously injected with the SHI-1 cell line. The tumor specimen was studied by the conventional pathologic examination. The mononuclear cells (MNC) of the tumor was assayed by RHG banding, the transcription of MLL-AF6 fusion gene and the VEGF gene was detected by RT-PCR. Gelatin zymography method was used to study the expression of MMP-9 and MMP-2 in the supernatant of the SHI-1 cell line. Matrigel invasion assay was employed for the study of migration of the SHI-1 cell in vitro. The results showed that the tumor masses were found in all sixteen mude mice after subcutaneous injection of SHI-1 cells, the tumor mass was mainly composed of leukemia cells, the transcription of MLL-AF6 fusion gene and VEGF gene was proved by RT-PCR analysis, the expressions of MMP-2 and MMP-9 in the serum-free culture supernatant of the SHI-1 cell line were significantly higher than those in U937, K562, and NB4 cell lines. The SHI-1 cell line exhibited significantly higher in vitro invasiveness than other leukemia cell lines, the blocking antibody of MMP-2 could inhibit the migration of the SHI-1 cell line significantly. It is concluded that the SHI-1 cell line presents higher tumorigenicity in nude mice than other leukemia cell line and the mechanism is associated with p53 gene alteration, high transcription level of VEGF gene, high expression level of MMP, and significantly higher invasiveness.
 ...
PMID:[High tumorigenicity of human acute monocytic leukemic cell Line SHI-1 in nude mice and its mechanism]. 1770 82

Angiogenesis plays an important role in the progression of tumors. This relationship has been described in several hematologic malignancies. Vascular endothelial growth factor and basic fibroblast growth factor are predictors of poor prognosis in leukemia and non Hodgkin's lymphoma. Bone marrow microvessels were found increased in multiple myeloma, but also in lymphoma and in acute lymphoblastic leukemia. Microvessel density is correlated with decreased survival in myeloma patients and relapse or resistance to chemotherapy in lymphoma. New drugs with antiangiogenic activity such as bevacizumab (binding and inactivation of VEGF) or VEGF-tyrosine kinase inhibitors have shown promising results in phase 1 trials. It will therefore be a future challenge to integrate anti-angiogenesis agents in currently existing treatment protocols to improve the outcome of therapy.
 ...
PMID:[Angiogenesis and hematologic malignancy]. 1784 10

Malignant effusions are a frequent problem for cancer patients. Due to the high resistance of tumor cells within these effusions, no effective treatment has been defined yet. Most patients exhibit additional phenomena related to hyper-coagulability such as elevated levels for d-dimers and prothrombin fragments f1.2; half of them suffer from manifest thrombosis or complications. We followed the hypothesis that the activated coagulation system contributes to the resistance of tumor cells and analyzed the effusions from cancer patients. The majority of isolated tumor cells aberrantly expressed PAR-1 thrombin receptors. In vitro pre-incubation of PAR-1 expressing human leukemia cells with thrombin resulted in a dose-dependent resistance to idarubicin. Within the effusions, we did not only find high concentrations of VEGF and tissue factor, but also all coagulation factors of the tissue factor pathway. Very high levels of prothrombin fragments f1.2 indicate constant thrombin generation. Upon the basis of these findings, we developed a multistep model elucidating the pathophysiological generation of malignant effusions, which might serve as a basis for further examinations.
 ...
PMID:[Coagulation and formation of malignant effusions]. 1793 66


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