scholarly journals The effects of combined antifolates on inhibition of growth of murine leukemia cells cultured in vitro.

1997 ◽  
Vol 44 (4) ◽  
pp. 743-750
Author(s):  
M Balińska ◽  
I Szablewska ◽  
D Janiszewska ◽  
K Bartuzi ◽  
K Pawełczak
Keyword(s):  
De Novo ◽  
Inhibitory Effect ◽  
Leukemia Cells ◽  
Intact Cells ◽  
Inhibition Of Growth ◽  
Prior Application ◽  
Thymidylate Synthesis ◽  
Derivatives Of ◽  
Murine Leukemia

The synergistic effect of trimetrexate (TMTX) and sulphonamide derivatives of quinazoline on the cultured 5178Y murine leukemia cells was examined. On exposure to the slightly inhibitory concentrations of TMTX (0.1 nM) in combination with 2-desamino-2-methyl-10-propargyl-5,8-dideaza-pteroyl-sulphoglyc ine (DMPDDSF) (0.02 microM) a synergistic inhibitory effect of the antifolates on cell growth was observed. These two drugs in the same combination caused also synergistic inhibition of de novo synthesis of thymidylate in intact cells as measured by tritium release from [5-(3)H]deoxyuridylate. This was accompanied by a marked reduction in intracellular concentration of 5,10-methylenetetrahydro-pteroyl-polyglutamate (5,10CH2H4PteGlu(n)) (0.2 microM) and dihydropteroyl-polyglutamate (0.12 microM). In these conditions de novo biosynthesis of purine was decreased by 50%. These observations show that growth inhibition by combined antifolates is mediated by intracellular depletion of the substrate of thymidylate synthase -- 5,10CH2H4PteGlu(n). The results obtained strongly suggest that under certain conditions inhibition of thymidylate synthesis by DMPDDSF is intensified by prior application of TMTX -- an inhibitor of dihydrofolate reductase.

scholarly journals Synergistic effect of 5-fluorodeoxyuridine and quinazoline antifolates on murine leukemia self-cultured in vitro.

1997 ◽  
Vol 44 (4) ◽  
pp. 735-742
Author(s):  
M Balińska ◽  
I Szablewska ◽  
D Janiszewska ◽  
A Brzezińska ◽  
K Pawełczak
Keyword(s):  
Synergistic Effect ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Leukemia Cells ◽  
Parental Line ◽  
Prior Use ◽  
Thymidylate Synthesis ◽  
Combined Drugs ◽  
Murine Leukemia

The effect of thymidylate synthase inhibitors, fluorodeoxyuridine (FdUrd) and its two sulphonamide derivatives was examined in the culture of murine leukemia cells -- 5178Y (parental subline) and its fluorodeoxyuridine resistant subline 5178Y/F. A synergistic effect of the antimetabolites on cell survival was observed on exposure of the culture of either line to a slightly inhibitory concentration of FdUrd (1 nM) in combination with 2-desamino-2-methyl-10-propargyl-5,8-dideaza-pteroylsulphogluta mate or 2-desamino-2-methyl-10-propargyl-5,8-dideaza-pteroylsulphoglyci ne. This effect was accompanied by a marked reduction, in both cell lines of intracellular concentration of 5,10-methylenetetrahydro-pteroyl-polyglutamate, although its concentration in the resistant subline was 3 times as high as in the parental line. The inhibitory effect of combined drugs on the cellular pool of folates in 5178Y line depended also on the sequence of drug addition, whereas in the FdUrd resistant line this sequence was without any effect. The results obtained strongly suggest that under certain conditions inhibition of thymidylate synthesis by antifolates is intensified by a prior use of FdUrd.

Aryl Maleimides as Apoptosis Inducers on L5178-Y Murine Leukemia Cells (in silico, in vitro and ex vivo Study)

2016 ◽  
Vol 16 (12) ◽  
pp. 1615-1621 ◽  
Author(s):  
Erik Andrade-Jorge ◽  
Marycarmen Godínez-Victoria ◽  
Luvia Enid Sánchez-Torres ◽  
Luis Humberto Fabila-Castillo ◽  
José G. Trujillo-Ferrara
Keyword(s):  
In Silico ◽  
Ex Vivo ◽  
Leukemia Cells ◽  
Ex Vivo Study ◽  
Murine Leukemia

scholarly journals Cytosolic localization and in vitro assembly of human de novo thymidylate synthesis complex

2020 ◽  
Author(s):  
Sharon Spizzichino ◽  
Dalila Boi ◽  
Giovanna Boumis ◽  
Roberta Lucchi ◽  
Francesca R. Liberati ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Protein Interactions ◽  
De Novo ◽  
Proximity Ligation Assay ◽  
Protein Protein Interactions ◽  
Aggregation State ◽  
Entire Complex ◽  
The Individual ◽  
Thymidylate Synthesis

ABSTRACTDe novo thymidylate synthesis is a crucial pathway for normal and cancer cells. Deoxythymidine monophosphate (dTMP) is synthesized by the combined action of three enzymes: thymidylate synthase (TYMS), serine hydroxymethyltransferase (SHMT) and dihydrofolate reductase (DHFR), targets of widely used chemotherapeutics such as antifolates and 5-fluorouracil. These proteins translocate to the nucleus after SUMOylation and are suggested to assemble in this compartment into the thymidylate synthesis complex (dTMP-SC). We report the intracellular dynamics of the complex in lung cancer cells by in situ proximity ligation assay, showing that it is also detected in the cytoplasm. We have successfully assembled the dTMP synthesis complex in vitro, employing tetrameric SHMT1 and a bifunctional chimeric enzyme comprising human TYMS and DHFR. We show that the SHMT1 tetrameric state is required for efficient complex assembly, indicating that this aggregation state is evolutionary selected in eukaryotes to optimize protein-protein interactions. Lastly, our results on the activity of the complete thymidylate cycle in vitro, provide a useful tool to develop drugs targeting the entire complex instead of the individual components.

scholarly journals Degradation of Myogenic Transcription Factor MyoD by the Ubiquitin Pathway In Vivo and In Vitro: Regulation by Specific DNA Binding

1998 ◽  
Vol 18 (10) ◽  
pp. 5670-5677 ◽  
Author(s):  
Ossama Abu Hatoum ◽  
Shlomit Gross-Mesilaty ◽  
Kristin Breitschopf ◽  
Aviad Hoffman ◽  
Hedva Gonen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
26S Proteasome ◽  
Intact Cells ◽  
Free System ◽  
Ubiquitin System

ABSTRACT MyoD is a tissue-specific transcriptional activator that acts as a master switch for skeletal muscle differentiation. Its activity is induced during the transition from proliferating, nondifferentiated myoblasts to resting, well-differentiated myotubes. Like many other transcriptional regulators, it is a short-lived protein; however, the targeting proteolytic pathway and the underlying regulatory mechanisms involved in the process have remained obscure. It has recently been shown that many short-lived regulatory proteins are degraded by the ubiquitin system. Degradation of a protein by the ubiquitin system proceeds via two distinct and successive steps, conjugation of multiple molecules of ubiquitin to the target protein and degradation of the tagged substrate by the 26S proteasome. Here we show that MyoD is degraded by the ubiquitin system both in vivo and in vitro. In intact cells, the degradation is inhibited by lactacystin, a specific inhibitor of the 26S proteasome. Inhibition is accompanied by accumulation of high-molecular-mass MyoD-ubiquitin conjugates. In a cell-free system, the proteolytic process requires both ATP and ubiquitin and, like the in vivo process, is preceded by formation of ubiquitin conjugates of the transcription factor. Interestingly, the process is inhibited by the specific DNA sequence to which MyoD binds: conjugation and degradation of a MyoD mutant protein which lacks the DNA-binding domain are not inhibited. The inhibitory effect of the DNA requires the formation of a complex between the DNA and the MyoD protein. Id1, which inhibits the binding of MyoD complexes to DNA, abrogates the effect of DNA on stabilization of the protein.

Design, synthesis and antibacterial evaluation of ocotillol derivatives with polycyclic nitrogen-containing groups

2021 ◽  
Author(s):  
Yucheng Cao ◽  
Kaiyi Wang ◽  
Jiali Wang ◽  
Haoran Cheng ◽  
Mengxin Ma ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Multidrug Resistant ◽  
Inhibitory Effect ◽  
Resistant Bacteria ◽  
Design Synthesis ◽  
In Vitro Antibacterial Activity ◽  
Strong Inhibitory Effect ◽  
Hospital Acquired ◽  
Derivatives Of

Aim: With the increasing abuse of antibacterial drugs, multidrug-resistant bacteria have become a burden on human health and the healthcare system. To find alternative compounds effective against hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA), novel derivatives of ocotillol were synthesized. Methods & Results: Ocotillol derivatives with polycyclic nitrogen-containing groups were synthesized and evaluated for in vitro antibacterial activity. Compounds 36–39 exhibited potent antibacterial activity against hospital-acquired MRSA, with MIC = 8–64 μg/ml. Additionally, a combination of compound 37 and the commercially available antibiotic kanamycin showed synergistic inhibitory effects, with a fractional inhibitory concentration index of ≤0.375. Conclusion: Compound 37 has a strong inhibitory effect, and this derivative has potential for use as a pharmacological tool to explore antibacterial mechanisms.

Beta-1 adrenergic inhibition of kallikrein release from rat kidney cortical slices

1990 ◽  
Vol 258 (5) ◽  
pp. F1425-F1431
Author(s):  
J. P. Girolami ◽  
J. L. Bascands ◽  
P. Valet ◽  
C. Pecher ◽  
G. Cabos
Keyword(s):  
De Novo ◽  
Rat Kidney ◽  
Inhibitory Effect ◽  
Significant Inhibition ◽  
Sodium Diet ◽  
Kidney Slices ◽  
Low Sodium Diet ◽  
Rat Cortical Slices ◽  
Cortical Slices

Renal storage; release, and biosynthesis of kallikrein were studied using rat cortical slices. This model permitted the study of the direct effect of norepinephrine on the renal kallikrein system in the absence of changes in perfusion pressure. Kallikrein was measured by its kininogenase activity and its direct immunoreactive concentration. Under basal conditions, rat kidney cortical slices synthesize and release glandular kallikrein in vitro at a linear rate for up to 40 min. Kidney slices obtained from rats fed with a low-sodium diet (LS) released more kallikrein into the incubation medium than slices from rats under a normal-sodium diet (NS). Cycloheximide and incubation at 4 degrees C inhibited the release and the biosynthesis of kallikrein independently of the sodium diet. Addition of norepinephrine (NE, 10(-8)-10(-5) M) induced a similar dose-dependent inhibition of kallikrein secretion, which reached -27 +/- 8% in NS rats and -29 +/- 9% in LS rats with 10(-7) M NE. This inhibition of the secretion was associated with an increase in tissue kallikrein concentration in kidney slices from rats on both sodium diets. However, a significant inhibition of the calculated net de novo synthesis was only observed in LS rats. In both groups of animals the ratio of active to total kallikrein was unchanged. The inhibitory effect of kallikrein secretion by NE was never modified in the presence of the alpha-antagonist phentolamine (10(-6) M). In contrast the beta-antagonist propranolol (10(-6) M) prevented the inhibitory effect of 10(-7) M NE.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Solanum lyratumExtracts Induce Extrinsic and Intrinsic Pathways of Apoptosis in WEHI-3 Murine Leukemia Cells and Inhibit Allograft Tumor

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Jai-Sing Yang ◽  
Chia-Chun Wu ◽  
Chao-Lin Kuo ◽  
Yu-Hsuan Lan ◽  
Chin-Chung Yeh ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Molecular Mechanisms ◽  
Fas Ligand ◽  
Leukemia Cells ◽  
Cycle Arrest ◽  
Phase Arrest ◽  
Apoptotic Pathways ◽  
Murine Leukemia

We investigated the molecular mechanisms of cell cycle arrest and apoptotic death induced bySolanum lyratumextracts (SLE) or diosgenin in WEHI-3 murine leukemia cellsin vitroand antitumor activityin vivo. Diosgenin is one of the components of SLE. Our study showed that SLE and diosgenin decreased the viable WEHI-3 cells and inducedG0/G1phase arrest and apoptosis in concentration- or time-dependent manners. Both reagents increased the levels of ROS production and decreased the mitochondrial membrane potential (ΔΨm). SLE- and diosgenin-triggered apoptosis is mediated through modulating the extrinsic and intrinsic signaling pathways. Intriguingly, the p53 inhibitor (pifithrin-α), anti-Fas ligand (FasL) mAb, and specific inhibitors of caspase-8 (z-IETD-fmk), caspase-9 (z-LEHD-fmk), and caspase-3 (z-DEVD-fmk) blocked SLE- and diosgenin-reduced cell viability of WEHI-3 cells. Thein vivostudy demonstrated that SLE has marked antitumor efficacy against tumors in the WEHI-3 cell allograft model. In conclusion, SLE- and diosgenin-inducedG0/G1phase arrest and triggered extrinsic and intrinsic apoptotic pathways via p53 activation in WEHI-3 cells. SLE also exhibited antitumor activityin vivo. Our findings showed that SLE may be potentially efficacious in the treatment of leukemia in the future.

scholarly journals Phosphorylation of lymphocyte myosin catalyzed in vitro and in intact cells.

1982 ◽  
Vol 93 (2) ◽  
pp. 261-268 ◽  
Author(s):  
M Fechheimer ◽  
J J Cebra
Keyword(s):  
Heavy Chain ◽  
Light Chain ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Intact Cells ◽  
Surface Immunoglobulin ◽  
Cell Extracts ◽  
Lymphocyte Populations ◽  
Immunologic Reactions

Myosin has been isolated from guinea pig B-lymphocytic leukemia cells (L2C). The myosin has been enzymatically phosphorylated and dephosphorylated in vitro using both heterologous and lymphocyte-derived enzymes. Both the heavy chain and 20,000-dalton light chain of lymphocyte myosin are phosphorylated in vitro. Phosphorylation of myosin enhances actin-activated ATPase activity. Phosphorylation of myosin in murine lymphocytes was analyzed by use of a novel technique for rapid immunoprecipitation of myosin from cell extracts. Both the heavy chain and 20,000-dalton light chain of myosin are phosphorylated in intact cells. Addition of antibody reactive with cell-surface immunoglobulin to lymphocyte populations enriched for B cells stimulates locomotion of these cells and also increases the quantity of 32P isolated in association with the 20,000-dalton light chain of lymphocyte myosin, when 32Pi was present in the medium. In addition, an unidentified, phosphorylated polypeptides with a molecular mass of 22,000 daltons is co-isolated with myosin from cells by rapid immunoprecipitation. These results are consistent with the hypothesis that phosphorylation of myosin may contribute to regulation of movements performed by lymphocytes which are related to their participation in immunologic reactions.

scholarly journals Flavin-Dependent Thymidylate Synthase ThyX Activity: Implications for the Folate Cycle in Bacteria

2007 ◽  
Vol 189 (23) ◽  
pp. 8537-8545 ◽  
Author(s):  
Damien Leduc ◽  
Frédéric Escartin ◽  
H. Frederik Nijhout ◽  
Michael C. Reed ◽  
Ursula Liebl ◽  
...  
Keyword(s):  
Dihydrofolate Reductase ◽  
Thymidylate Synthase ◽  
Insertional Mutagenesis ◽  
Rhodobacter Capsulatus ◽  
De Novo ◽  
Reductase Activity ◽  
Direct Proof ◽  
Cellular Functions ◽  
Thymidylate Synthesis

ABSTRACT Although flavin-dependent ThyX proteins show thymidylate synthase activity in vitro and functionally complement thyA defects in heterologous systems, direct proof of their cellular functions is missing. Using insertional mutagenesis of Rhodobacter capsulatus thyX, we constructed the first defined thyX inactivation mutant. Phenotypic analyses of the obtained mutant strain confirmed that R. capsulatus ThyX is required for de novo thymidylate synthesis. Full complementation of the R. capsulatus thyX::spec strain to thymidine prototrophy required not only the canonical thymidylate synthase ThyA but also the dihydrofolate reductase FolA. Strikingly, we also found that addition of exogenous methylenetetrahydrofolate transiently inhibited the growth of the different Rhodobacter strains used in this work. To rationalize these experimental results, we used a mathematical model of bacterial folate metabolism. This model suggests that a very low dihydrofolate reductase activity is enough to rescue significant thymidylate synthesis in the presence of ThyX proteins and is in agreement with the notion that intracellular accumulation of folates results in growth inhibition. In addition, our observations suggest that the presence of flavin-dependent thymidylate synthase X provides growth benefits under conditions in which the level of reduced folate derivatives is compromised.

Methylation and expression of the Myo D1 determination gene

1990 ◽  
Vol 326 (1235) ◽  
pp. 277-284 ◽  
Keyword(s):  
De Novo ◽  
Cell Types ◽  
Model System ◽  
Parental Line ◽  
Molecular Control ◽  
Embryo Cells ◽  
End Stage ◽  
Derivatives Of

Mouse embryo cells induced to differentiate with the demethylating agent 5- azacytidine represent an excellent model system to investigate the molecular control of development. Clonal derivatives of 10T1/2 cells that have become determined to the myogenic or adipogenic lineages can be isolated from the multipotential parental line after drug treatment. These determined derivatives can be cultured indefinitely and will differentiate into end-stage phenotypes on appropriate stimulation. A gene called Myo D1, recently isolated from such a myoblast line, will confer myogenesis when expressed in 10T1/2 or other cell types (Davis et al. 1987). The cDNA for Myo D1 contains a large number of CpG sequences and the gene is relatively methylated in 10T1/2 cells and an adipocyte derivative, but is demethylated in myogenic derivatives. Myo D1 may therefore be subject to methylation control in vitro . On the other hand, preliminary observations suggest that Myo D1 is not methylated at CCGG sites in vivo so that a de novo methylation event may have occurred in vitro . These observations may have significance in the establishment of immortal cell lines and tumours.

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