Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is now well documented that apoptosis represents the prevalent mode of cell death in hybridoma cultures. Apoptotic or programmed cell death occurs spontaneously in late exponential phase of batch cultures. Until lately, no specific triggering factors had been identified. Recently, we observed that glutamine, cystine or glucose deprivation induced apoptosis in both hybridoma and myeloma cell lines whereas accumulation of toxic metabolites induced necrotic cell death in these cells. Other triggering factors such as oxygen deprivation might also be responsible for induction of apoptosis. In the present study, induction of cell death by exposure to anoxia was examined in batch culture of the SP2/0-derived hybridoma D5 clone. The mode of cell death was studied by morphological examination of acridine orange-ethidium bromide stained cells in a 1.5 L bioreactor culture grown under anoxic conditions for 75 hours. Under such conditions, viable cell density levelled off rapidly and remained constant for 25 hours. After 45 hours of anoxia, cell viability had decreased to 30% and the dead cell population was found to be 90% apoptotic. In terms of cellular metabolism, anoxia resulted in an increase in the utilization rates of glucose and arginine, and in a decrease in the utilization rate of glutamine. The lactate production rate and the yield of lactate on glucose increased significantly while the MAb production rate decreased. These results demonstrate that glycolysis becomes the main source of energy under anoxic conditions. Cells incubated for 10 hours or less under anoxic conditions were able to recuperate almost immediately and displayed normal growth rates when reincubated in oxic conditions whereas cells incubated for 22 hours or more displayed reduced growth rates. Nonetheless, even after 22 h or 29 h of anoxia, cells reincubated in oxic conditions showed no further progression into apoptosis. Therefore, upon removal of the triggering signal, induction of apoptosis ceased.
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PMID:Induction of apoptosis in oxygen-deprived cultures of hybridoma cells. 776 24

Human peripheral blood eosinophils adhered specifically to microtitre plates coated with plasma fibronectin (Fn) in a dose- and time-dependent fashion. Adhesion was optimal at 60 min at a concentration of 100 micrograms/ml. Adherence to Fn was up-regulated by platelet-activating factor (PAF; optimum concentration of 10(-6) M) and was significantly inhibited by a polyclonal anti-Fn antibody (P < 0.05). The following evidence suggested that eosinophil adhesion to Fn was mediated by alpha 4 beta 1: (1) eosinophil adherence to Fn was not inhibited by an Arg-Gly-Asp-Ser (RGDS) synthetic peptide; (2) there was a dose-dependent adherence of eosinophils to microtitre plates coated with the 40,000 MW proteolytic fragment of Fn that contains the CS-1 alpha 4 beta 1 binding region, whereas adherence to the 120,000 MW chymotryptic fragment of Fn, which contains the RGD-dependent binding site, was weak and only observed at high concentrations (> 250 micrograms/ml); (3) significant inhibition of eosinophil adherence to Fn was achieved by monoclonal antibodies (mAb) against the alpha chain of VLA-4 but not by a mAb against CD45 or a mouse myeloma antibody as negative controls. After adhesion to Fn, eosinophils were investigated for their capacity to release leukotriene C4 in response to stimulation with a suboptimal concentration of calcium ionophore (2 x 10(-6) M). Significant enhancement of release was detected with Fn-coated plates but not with the control bovine serum albumin (BSA) (P < 0.01). Furthermore, this enhancement was significantly inhibited by the alpha 4 beta 1 mAb HP2/1 (P < 0.05) but not by an anti-CD45 mAb. From these studies we conclude that (1) alpha 4 beta 1 (VLA-4) integrin is a major receptor for Fn on human eosinophils and (2) adhesion to Fn may prime eosinophils for mediator release during allergic inflammation.
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PMID:Adhesion to fibronectin primes eosinophils via alpha 4 beta 1 (VLA-4). 792 93

Bence Jones proteins purified from urine of patients with multiple myeloma were found to be capable of hydrolyzing carbobenzoxy-L-valyl-glycyl-L-arginine p-nitroanilide (Chromozym TRY) and benzoyl-L-arginine p-nitroanilide (BApNA), synthetic chromogenic substrates for trypsin. The amidolytic activity obeyed classic Michaelis-Menten kinetics, exhibiting optimal activity around pH 8.4 and apparent Km of 140-730 microM and 18-27 microM for Chromozym TRY and BApNA, respectively. No activity was detected with intact IgG or Fab fragment, whereas the activity comparable to those of Bence Jones proteins was found with light chain derived from inactive IgG. Several lines of circumstantial evidence indicate that the observed activity was not due to contaminating enzyme.
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PMID:Amidase activity of human Bence Jones proteins. 794 92

A myeloma cell line (KHM-4) from a patient with multiple myeloma and idiopathic hyperammonemia, and another myeloma cell line (RPMI8226) were seen to have activity to form ammonia from arginine. High activity of ornithine transcarbamylase (OTC), a hepatic urea cycle enzyme, was detected in these cell lines. OTC of these cells was much more heat-stable than the liver enzyme, and did not cross-react with an antibody against the liver enzyme. As the OTC activity was also detected in the culture medium of the myeloma cells and because the activity was markedly decreased by the antimycoplasma drug MC-210, the OTC activity was assumed to be associated with mycoplasma infection. Polymerase chain reaction, using degenerate oligonucleotide mixtures corresponding to the two highly conserved sequences of OTC, amplified a DNA sequence that apparently encodes a portion (about 67% in length) of mycoplasma OTC. The predicted amino acid sequence of the mycoplasma enzyme was 33-47% identical with those of the enzymes of bacteria, yeast and mammals.
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PMID:A novel ornithine transcarbamylase present in mycoplasma-infected myeloma cells. 819 71

We have developed a procedure to purify the recombinant fusion toxin IL6-PE4E from Escherichia coli which results in a high yield of fully active monomeric protein of high purity and very low endotoxin content. The chimeric toxin is composed of human interleukin 6 (IL6) fused to a derivative of Pseudomonas exotoxin (PE) containing mutations in the binding domain which prevent binding to the PE receptor. In a typical preparation, 20 g of E. coli cells expressing the plasmid encoding IL6-PE4E were treated with lysozyme and washed repeatedly with detergent (Triton X-100), to obtain 500 mg of inclusion bodies. The recombinant protein was denatured and reduced in guanidine hydrochloride solution containing dithioerythritol and refolded in a redox buffer containing oxidized glutathione and L-arginine. After purification of the dialyzed protein by anion-exchange, polymyxin B, and sizing chromatography, we obtained 100 mg (20% of recombinant protein) of purified monomer with 0.6-2.5 endotoxin units/mg of protein. Amino terminal sequencing confirmed the first 20 amino acids. IL6-PE4E purified in this manner was fully cytotoxic toward human multiple myeloma, hepatoma, epidermoid carcinoma, and prostate carcinoma cell lines. After intravenous injection into mice, we found the dose-limiting toxicity to be to the liver, by measurement of serum transaminases and histologic evaluation of the liver. The LD50 was 450 micrograms/kg. We conclude that IL6-PE4E can be purified efficiently for preclinical testing.
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PMID:Purification and characterization of IL6-PE4E, a recombinant fusion of interleukin 6 with Pseudomonas exotoxin. 830 30

Peptichemio (PTC) is a mixture of six synthetic oligopeptides, each of which contains the alkylating residue m-[di(2-chloroethyl)amino]-L-phenylalanine (L-mSL). The fate of PTC was investigated in eight patients with multiple myeloma after intravenous infusion of the drug. The quantitative analysis of the plasma samples was performed by liquid chromatography with fluorometric detection. L-mSL was rapidly released from the peptides and reached its maximal plasma concentration at the end of the infusion. Its median elimination half-life was 1.73 (range, 0.72-2.41) h. It was possible to follow the concentration of only one of the peptides, L-mSL-L-Arg(NO2)-L-Nval.OEt, during and shortly after the infusion of PTC. The stability of L-mSL and the peptides was studied in buffer solution (pH 7.3), plasma, and blood. The stability of some of the peptides was drastically decreased in blood, the degradation half-lives being only about 1 min. We conclude that L-mSL plays an important role in the mechanism of action of PTC.
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PMID:Pharmacokinetics of peptichemio in myeloma patients: release of m-L-sarcolysin in vivo and in vitro. 842 88

A subclone of the EoL-3 human eosinophilic leukemia cell line (EoL-3.12) was selected for its high inducibility of CD23 (low affinity IgE receptor/Fc epsilon RII) by IL-4. Maximum membrane CD23 expression was detected after 16 h of incubation with IL-4, then gradually returned to basal level after 48 h. Membrane expression of CD23 on EoL-3.12 cells was found to parallel their homotypic aggregation. Extending the time of incubation with IL-4 to 48 h or more resulted in a de-aggregation of cells of cells with a shedding of membrane CD23 and an increase of its soluble form, sCD23. The IL-4-induced aggregation of EoL-3.12 cells was inhibited with anti-CD23 antibody or human myeloma IgE protein, indicating that it was mediated through the engagement of CD23. EoL3.12 incubated with IL-4 displayed morphological changes associated with differentiation, such as an increased number of lobulated nuclei with prominent nucleoli, increased ratio of cytoplasm and distinct cytoplasmic processes. EoL-3.12 cells incubated with IL-4 also displayed an enhanced adherence to human umbilical vein endothelial cells (HUVEC), which was reverted when the IL-4 incubation time extended. Furthermore, the transendothelial migration of EoL-3.12 cells toward a chemokinetic gradient of soluble CD23 (sCD23; 29 kDa fragment) closely paralleled the density of membrane CD23 expressed on EoL-3.12 cells. Additionally, the engagement of CD23 led to the activation of the L-arginine-dependent pathway of nitric oxide (NO) production, as detected by the increase in intracytoplasmic cGMP concentration. The capacity of EoL-3.12 cells to form homotypic as well as heterotypic adhesion appears therefore to be regulated, at least in part, by the level of CD23 expression.
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PMID:Involvement of CD23/Fc epsilon RII in the homotypic and heterotypic cytoadhesion of the human eosinophilic cell line Eol-3. 858 71

Bence Jones proteins were capable of hydrolyzing a peptide bond between arginine-8 and the C-terminal glycinamide of vasopressin. This peptidolytic activity obeyed typical Michaelis-Menten kinetics and exhibited optimal activity at pH 8.2 and Km of 0.6-1.9 mM. The catalytic efficiency, kcat/Km, was calculated to be 0.8 to 5.8 min(-1)M(-1). The Bence Jones proteins displayed turnover, an essential feature of enzymes. These results suggest that slow proteolysis, especially in the renal tubules which are 'saturated' with Bence Jones proteins, may have a pathophysiological significance for various nephropathies often associated with multiple myeloma with Bence Jones proteinuria.
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PMID:Catalytic cleavage of vasopressin by human Bence Jones proteins at the arginylglycinamide bond. 906 57

Both alpha-linolenic (ALA) and eicosapentaenoic acids (EPA) were toxic to SP 2/0 mouse myeloma cells in vitro. On the other hand, linoleic acid (LA), gamma-linolenic acid (GLA), di-homo-gamma linolenic acid (DGLA), arachidonic acid (AA), docosahexaenoic acid (DHA) and oleic acid (OA) were much less effective in their growth suppressive actions. Both nordihydroguaiaretic acid (NDGA) and Indomethacin (IM) could block the action of the fatty acids indicating a role for prostaglandins (PGs) and leukotrienes (LTs) in the growth suppressive action of ALA and EPA. Superoxide dismutase (SOD) completely blocked, while vitamin E and reduced glutathione (GSH) could prevent to a limited extent the anti-proliferative effects of ALA and EPA. Catalase, mannitol, chlorpromazine (CPZ) and trifluoperazine (TFP) did not block the cytotoxic actions of ALA and EPA. N(G)-mono-methyl L-arginine (N(G)MMA), an analogue of L-arginine, which inhibits nitric oxide synthase, was ineffective in preventing the cytotoxicity induced by ALA and EPA. Fatty acid analysis of the various lipid fractions of SP 2/0 cells treated with ALA and EPA showed significant incorporation of these fatty acids in the cell membrane lipid pools. These results suggest that ALA and EPA induced suppression of SP 2/0 cell proliferation is cyclo-oxygenase (CO), lipoxygenase (LO) and superoxide dependent. Lipid peroxidation has only a limited role in this process. Both calmodulin dependent process and L-arginine derived nitric oxide do not seem to have a role in the cytotoxic action of ALA and EPA in these cells.
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PMID:Cytotoxic action of alpha-linolenic and eicosapentaenoic acids on myeloma cells in vitro. 915 Mar 74

Of 18 monoclonal Bence Jones proteins purified from urine of patients with multiple myeloma, 4 were found to have a DNA-nicking activity. In contrast, all Bence Jones proteins tested showed detectable amidase activity against carbobenzoxy-L-valyl-glycyl-L-arginine p-nitroanilide. No correlation between the two activities was found. Four patients excreting Bence Jones protein with the DNA-nicking activity showed somewhat severe symptoms, suggesting that this activity may be related to the progressive deterioration of clinical status.
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PMID:DNA-hydrolyzing activity of Bence Jones proteins. 950 Sep 93


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