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

Here we show that in vitro supplementation of L1210 murine lymphoblastic leukaemia cells with n-3 polyunsaturated fatty acids results in considerable changes in the fatty acid composition of membrane phospholipids. Incubations for 48 h with 30 microM eicosapentaenoic acid (20:5, n-3; EPA) or docosahexaenoic acid (22:6, n-3; DHA) results primarily in substitution of long chain n-6 fatty acids with long-chain n-3 fatty acids. This results in a decrease in the n-6/n-3 ratio from 6.9 in unsupplemented cultures to 1.2 or 1.6 for EPA and DHA supplemented cultures, respectively. Coincident with these changes in membrane fatty acid composition, we observed a 5-fold increase in the rate of adenosine (5 microM) uptake via a nitrobenzylthioinosine (NBMPR)-sensitive nucleoside transporter in EPA- and DHA-supplemented L1210 cells, relative to unsupplemented cells. This seemed to result from a decrease in the Km for adenosine from 12.5 microM in unsupplemented cultures to 5.1 microM in DHA-treated cultures. Guanosine (50 microM) transport was similarly affected by DHA with a 3.5-fold increase in the initial rate of uptake. In contrast, pyrimidine transport, as measured by uptake of thymidine and cytidine, was not similarly affected, suggesting that substrate recognition had been altered by fatty acid supplementation. Studies using [(3)H]NBMPR showed that there was no effect of EPA or DHA on either the number of NBMPR-binding sites or the affinity of these sites for NBMPR. This observation suggests that the increases in adenosine and guanosine transport were not due to increases in the number of transported sites but rather that EPA and DHA directly or indirectly modulate transporter function.
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PMID:Omega-3 polyunsaturated fatty acids increase purine but not pyrimidine transport in L1210 leukaemia cells. 867 Jan 26

92-kDa type IV collagenase/gelatinase (matrix metalloproteinase-9; MMP-9; gelatinase B) expression and secretion has been shown to correlate with the invasive and metastatic potential of various malignant cells. MMP activity is tightly controlled by specific tissue inhibitors of metalloproteinases (TIMPs). We found the leukemic cell line HL-60 constitutively to release a 94-kDa gelatinase which we identified as MMP-9 shortened by nine amino acids at its N-terminal end. An additional gelatinolytic activity was present in small amounts and identified as a 63-kDa fragment of MMP-9 generated by autocatalytical processing. Both enzymes were identical regarding their N-terminus, indicating C-terminal truncation for the former. Incubation of cells with phorbol ester resulted in elevated amounts of both enzymes in conditioned media and in the secretion of TIMP-1. Both gelatinases were shown to be activated by trypsin and organomercurials and to possess similar activities towards various substrates. However, the 63-kDa enzyme differed from the 94-kDa enzyme in a significantly reduced inhibition by recombinant TIMP-1 and TIMP-2. Thus, the 63-kDa fragment of MMP-9 once activated may escape the regulatory influence of its specific inhibitors and may thereby promote matrix degradation during invasion of leukemic cells.
Leukemia 1996 Sep
PMID:HL-60 leukemia cells produce an autocatalytically truncated form of matrix metalloproteinase-9 with impaired sensitivity to inhibition by tissue inhibitors of metalloproteinases. 875 73

We quantified tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in serum and plasma in normal control subjects and patients with a low or high platelet count, using one-step sandwich enzyme immunoassays. The serum levels of TIMP-1 and TIMP-2 were 101.1 +/- 13.3 ng/ml, and 82.7 +/- 26.3 ng/ml, respectively, in normal subjects. In patients with an elevated platelet count, such as in essential thrombocytosis, polycythaemia vera, and myelofibrosis, serum levels of TIMP-1 and TIMP-2 were 351.6 +/- 200.9 ng/ml and 148.9 +/- 84.0 ng/ml, respectively. Serum levels of TIMP-1 and TIMP-2 in patients with a low platelet count, such as in aplastic anaemia and idiopathic thrombocytopenic purpura, were 57.2 +/- 25.8 ng/ml and 19.7 +/- 7.68 ng/ml, respectively. The serum level of TIMP-1 was significantly correlated with the platelet count in all subjects. The correlation between the serum level of TIMP-2 and the platelet count was not as strong. The level of TIMP-1 in platelet-depleted plasma was not correlated with the platelet count. Immunohistochemical staining using monoclonal antibodies against TIMP-1 and TIMP-2 showed that megakaryocytes and platelets were positive for both TIMP-1 and TIMP-2, confirming that they are rich sources of TIMPs. TIMP-1 and TIMP-2 stimulated the proliferation of bone marrow fibroblasts, although their effect was less potent than that of TGF-beta and PDGF. Erythroleukaemia and megakaryoblastic cell lines showed the highest secretion of TIMP-1 among the leukaemia cell lines examined. There was no lineage specificity for TIMP-2 secretion. These results suggest that TIMPs released from megakaryocytes or from local platelet coagulation may be important in the development of bone marrow fibrosis.
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PMID:The production of tissue inhibitors of metalloproteinases (TIMPs) in megakaryopoiesis: possible role of platelet- and megakaryocyte-derived TIMPs in bone marrow fibrosis. 935 22

Polyunsaturated fatty acids (PUFA) may reduce cell multiplication in cultures of normal, as well as transformed, white blood cells. We assessed the sensitivity of 14 different leukemia cell lines to PUFA by measuring cell number after 3 days of incubation. Ten of the examined cell lines were sensitive to 30, 60 and/or 120 microM of arachidonic, eicosapentaenoic and docosahexaenoic acid, whereas four cell lines were resistant. The sensitivity to PUFA was not associated with any particular cell lineage, clinical origin or specific mRNA pattern of bcl-2 and c-myc. Effects on cell viability were assessed by studying cell membrane integrity, DNA fragmentation and cell morphology. The sensitive cell lines Raji and Ramos died by necrosis and apoptosis, respectively, during incubation with eicosapentaenoic acid, whereas the viability of the resistant U-698 cell line was unaffected. The effects of EPA on Raji cells, was counteracted by vitamin E, indicating that lipid peroxidation was involved. However, apoptosis induced by eicosapentaenoic acid in Ramos cells, was unaffected by vitamin E, as well as eicosanoid synthesis inhibitors. In conclusion, our results indicate that a majority of leukemia cell lines are sensitive to PUFA. This sensitivity may be caused by induction of apoptosis or necrosis by very long-chain polyunsaturated fatty acids.
Leukemia 1998 Jun
PMID:Multiplication and death-type of leukemia cell lines exposed to very long-chain polyunsaturated fatty acids. 963 21

Bleomycin is an antitumor agent which is a mixture of glycopeptides containing at least 55-75% bleomycin A2 and 25-32% bleomycin B2 fractional composition. Two bleomycin formulations, bleomycin sulfate, USP (Blenoxane, Bristol-Myers Squibb Oncology, Princeton, N.J.) and bleomycin HCI (Tianjin Hebei Pharmaceutical, Tianjin, China) were compared analytically and biologically. Reverse-phase high-performance liquid chromatography (HPLC) analyses using the USP methodology showed that Blenoxane contained primarily (69%) bleomycin A2 and 29.3% bleomycin B2. In contrast, Tianjin-supplied bleomycin HCI contained 97% bleomycin A5 fraction. In vitro tumor cell growth inhibition assays showed equivalent activity in human OVCAR-3 ovarian cancer cells and slightly greater potency in murine L-1210 leukemia cells for the Tianjin formulation. In C57/B1 mice bearing B-16 melanoma tumors, Tianjin-supplied bleomycin produced slightly greater tumor growth inhibition at the expense of greater drug-induced lethality at higher dose levels. These studies show there are significant differences in two international bleomycin formulations. These compositional differences lead to altered biologic effects.
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PMID:Analytical and biological inequivalence of two commercial formulations of the antitumor agent bleomycin. 965 15

A cytotoxic factor (CF) toward cultured murine leukemia L1210 cells was induced in mouse serum by intravenous injection of a dehydrogenation polymer of p-coumaric acid (DHP-pCA). When the serum from the treated mice was diluted with ethanol, CF was preserved in its supernatant (EtOH-sup). An EtOH-sup prepared from untreated control mice also showed cytotoxicity, although at much higher concentrations. The CF activity of EtOH-sups from both treated and untreated mice was completely eliminated by acid treatment at pH 2 at 90 degrees C for 30 min but kept intact by alkali treatment. In addition, the CF activity of both EtOH-sups was not affected by digestion with chymotrypsin. CF was recovered in a neutral MeOH-eluate from a DEAE-cellulofine column but not in HCI-MeOH eluate, in which lignified materials including DHP-pCA should have been recovered. These findings strongly suggest that CF is not a metabolite of DHP-pCA but an endogenous component of the normal serum which is augmented by DHP-pCA administration.
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PMID:Cytotoxic factor induced in murine serum after intravenous administration of a dehydrogenation polymer of p-coumaric acid (a synthetic lignin). 982 18

We compared the expression of matrix metalloproteinases (MMP-2 and MMP-9) and tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in bone marrow acute myelogenous leukaemia (AML) blasts and leukaemic cell lines (HEL, HL-60, K-562 and KG-1) with their expression in normal bone marrow cells. All AML samples and leukaemic cell lines tested expressed MMP-9 and/or MMP-2 mRNA and, accordingly, these gelatinases were secreted into media. Moreover, TIMP-1 and TIMP-2 mRNA and secreted proteins were demonstrated in all the AML samples. Although all the leukaemic cell lines expressed TIMP-1, the HL-60 cells also expressed TIMP-2. In contrast, normal steady-state bone marrow immature progenitor cells (CD34+ cells) did not express or secrete either MMP-2 or MMP-9, but more mature mononuclear cells from normal bone marrow expressed and secreted MMP-9. Also, normal bone marrow CD34+ cells and mononuclear cells expressed TIMP-1 and TIMP-2 mRNA, but these proteins were not detectable by reverse zymography. Furthermore, whereas bone marrow fibroblasts and endothelial cells secreted only latent MMP-2, the activated form of this enzyme was found in media conditioned by cells obtained from long-term cultures of normal and AML bone marrow adherent layers. Our finding of up-regulated production of gelatinases, TIMP-1 and TIMP-2 by leukaemic cells suggests that these proteins may be implicated in the invasive phenotype of AML.
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PMID:Expression of matrix metalloproteinases (MMP-2 and -9) and tissue inhibitors of metalloproteinases (TIMP-1 and -2) in acute myelogenous leukaemia blasts: comparison with normal bone marrow cells. 1023 11

We have reported previously that unsymmetrical disulfide inhibitors of the human thioredoxin/thioredoxin reductase redox system (hTrx/TR) possess antitumor activity. We have broadened the search for more potent inhibitors and evaluated a large range of mono- and bis-disulfide compounds, prepared using parallel syntheses. Reaction of isothioisourea-HCI salts (R') or bis-salts (R) with aromatic or aryl thiols (R") in wells of 96-well plates produced >450 derivatives with the structures R"SSR' and R"SSRSSR". The excellent yield and purity of the disulfides provided sufficient material for evaluations of enzyme inhibition and cytotoxicity. Selection criteria based on the IC50 values for hTrx/TR inhibition and for cytotoxicities of the disulfides identified agents for subsequent scale-up syntheses and in vivo evaluations of antitumor activity. These scale-up studies confirmed the original activities of agents synthesized in the plates and validated the parallel synthetic approach. Structure-activity information derived from the hTrx/TR IC50 data allow for a number of generalizations. The most potent inhibitors of the Trx system contained two heteroatoms ortho to the disulfide moiety in an aromatic functionality. The thioalkylating moieties had greatest activity with one branch point alpha to the disulfide. In the absence of branching, more potent inhibition was observed with the electron withdrawing functionalities. Bis-disulfides showed patterns of activity which depended on chain length, with optimum activity observed when the disulfide units were separated by 3.9 A, a similar distance to that separating the thioredoxin active site cysteine residues. From the agents selected for scale-up syntheses, three disulfide compounds were studied for their antitumor activity in vivo against human tumor xenografts in scid mice. One of the analogues discovered through the combinatorial syntheses/screening for Trx inhibition, 1-phenylethyl 2-imidazolyl disulfide, N1 (ProlX agent PX-C5), has demonstrated excellent in vivo activity against the MCF-7 human breast cancer and the HL-60 human leukemia, thus validating this approach for novel drug discovery.
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PMID:Parallel syntheses of disulfide inhibitors of the thioredoxin redox system as potential antitumor agents. 1076 97

The matrix metalloproteinases (MMPs) are important in tumour cell invasion and metastasis in many common cancers. However, relatively few studies have investigated the role of MMPs and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), in leukaemia cell invasion. This study examined two leukaemia cell lines, K562 and HL-60 and showed that the K562 cell line was four times more invasive than the HL-60 cell line. The expression of MMP-2, matrilysin (MMP-7), MMP-9. TIMP-1, TIMP-2 and TIMP-3 was analysed. Both cell lines produced similar amounts of MMP-2, MMP-9 and TIMP-2. The K562 cells expressed more TIMP-1 than the HL-60 cells and neither cell line expressed TIMP-3. Interestingly, only the K562 cells expressed matrilysin suggesting a potential role for matrilysin in leukaemia cell invasion. in vitro invasion assays performed in the presence of a matrilysin blocking antibody showed a 40% reduction in invasive ability. This data suggests that matrilysin plays an important role in leukaemia cell invasion.
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PMID:The role of matrilysin (MMP-7) in leukaemia cell invasion. 1146 72

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) regulate the turnover of the extracellular matrix and may modulate the biology of haematopoietic cells. We investigated whether MMPs and TIMPs are produced in long-term marrow cultures (LTMCs) established from normal donors and acute myelogenous leukaemia (AML) patients, and by fibroblast- (F), granulocyte macrophage- (GM) and megakaryocyte- (Meg) colony-forming unit (CFU) and erythroid burst-forming unit (BFU-E)-derived precursor cells. ProMMP-9 levels were highest (> 400 ng/ml) at week 1 of normal LTMC, whereas proMMP-2, TIMP-1, TIMP-2 and TIMP-3 levels peaked (up to 1000 ng/ml) after the establishment of the adherent layer. In LTMC from AML patients, these patterns of secretion were reversed. Moreover, we found that after a 24 h incubation in serum-free media, normal CFU-GM-, BFU-E- and CFU-Meg-derived cells secreted proMMP-9 and CFU-F-derived cells proMMP-2, in contrast to cells from LTMC adherent layer which secreted both active and latent forms of MMP-2 and MMP-9 under serum-free conditions. However, when these adherent cells were incubated in 12.5% fetal calf or horse serum or complete LTMC growth media, active forms of MMP-2 and MMP-9 were no longer detectable, and TIMP levels increased. Hence, we concluded that (i) MMPs/TIMPs are secreted by normal human bone marrow haematopoietic and stromal cells and may play an important role in intercellular cross-talk in haematopoiesis; and (ii) only latent forms of MMPs are present under LTMC conditions, indicating that the specific media used for weekly re-feeding of LTMC can block activation of MMP-2 and MMP-9, maintaining the integrity of the stromal layer and supporting haematopoiesis in vitro.
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PMID:Matrix metalloproteinase and tissue inhibitors of metalloproteinase secretion by haematopoietic and stromal precursors and their production in normal and leukaemic long-term marrow cultures. 1173 41


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