scholarly journals Inhibition of a nutrient-dependent pinocytosis in dictyostelium discoideum by the amino acid analogue hadacidin

1981 ◽  
Vol 91 (1) ◽  
pp. 227-231 ◽  
Author(s):  
EF Rossomando ◽  
EG Jahngen ◽  
B Varnum ◽  
DR Soll
Keyword(s):  
Dictyostelium Discoideum ◽  
Growth Medium ◽  
Cellular Proliferation ◽  
Growth Arrest ◽  
Fluorescein Isothiocyanate ◽  
Dependent Manner ◽  
Percent Reduction ◽  
Concentration Dependent Manner ◽  
Acid Analogue ◽  
In Cells

In the present study we examine the effects of the drug hadacidin (N-formyl-N- hydroxyglycine) on pinocytosis in the eukaryotic microorganism dictyostelium discoideum. At concentrations of up to approximately 8 mg/ml, hadacidin inhibited the rate of pinocytosis of fluorescein isothiocyanate (FITC) dextran in cells in growth medium in a concentration-dependent manner but had no effect on cells in starvation medium. Because hadacidin also inhibits cellular proliferation at this concentration, the relationship between growth rate and pinocytosis was studied further using another drug, cerulenin, to produce growth-arrest. These experiments showed no changes in the rate pinocytosis even after complete cessation of cellular proliferation. Other studies showed that the transfer of cells from growth to starvation medium reduced the rate of pinocytosis by approximately 50 percent. A reduction of similar magnitude occurred if cells were transferred from growth to starvation medium containing hadacidin. Also, no additional reduction in pinocytosis occurred when cells that had been treated with hadacidin were transferred to starvation medium containing hadacidin. These cells were able to take up [(14)C]hadacidin in the starvation medium. In contrast to the results with hadacidin-treated cells, cells in a cerulenin-induced state of growth-arrest when transferred to starvation medium exhibited the same 50 percent reduction in pinocytosis observed in cells not previously exposed to either drug. Cells treated with azide, in either growth or starvation medium, exhibited an immediate inhibition of all pinocytotic activity. After the transfer of log-phase cells to starvation medium supplemented with glucose, the reduction in rate was only approximately 10-15 percent. In contrast, a 50 percent reduction was observed after supplementation of starvation medium with sucrose, KCl, or concanavalin A. Maintaining the cells in growth medium containing hadacidin for as long as 16 h had no effect on the rate at which cells aggregated. These results are consistent with the conclusion that D. discoideum exhibits two types of pinocytotic activity: one that is nutrient dependent and the other independent of nutrients. This latter activity persists in starvation medium and is unaffected by hadacidin, whereas the nutrient-dependent activity is present in growth medium and is inhibited by hadacidin.

scholarly journals Sphingosine Kinase as a Regulator of Calcium Entry through Autocrine Sphingosine 1-Phosphate Signaling in Thyroid FRTL-5 Cells

Endocrinology ◽  
2009 ◽  
Vol 150 (11) ◽  
pp. 5125-5134 ◽  
Author(s):  
Dan Gratschev ◽  
Christoffer Löf ◽  
Jari Heikkilä ◽  
Anders Björkbom ◽  
Pramod Sukumaran ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Sphingosine Kinase ◽  
Calcium Entry ◽  
Dominant Negative ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Entry Pathway ◽  
Sphingosine 1 Phosphate ◽  
S1p Receptor ◽  
In Cells

Calcium entry is one of the main regulators of intracellular signaling. Here, we have described the importance of sphingosine, sphingosine kinase 1 (SK1), and sphingosine 1-phosphate (S1P) in regulating calcium entry in thyroid FRTL-5 cells. In cells incubated with the phosphatase inhibitor calyculin A, which evokes calcium entry without mobilizing sequestered intracellular calcium, sphingosine inhibited calcium entry in a concentration-dependent manner. Furthermore, inhibiting SK1 or the ATP-binding cassette ABCC1 multidrug transporter attenuated calcium entry. The addition of exogenous S1P restored calcium entry. Neither sphingosine nor inhibition of SK1 attenuated thapsigargin-evoked calcium entry. Blocking S1P receptor 2 or phospholipase C attenuated calcium entry, whereas blocking S1P receptor 3 did not. Overexpression of wild-type SK1, but not SK2, enhanced calyculin-evoked calcium entry compared with mock-transfected cells, whereas calcium entry was decreased in cells transfected with the dominant-negative G82D SK1 mutant. Exogenous S1P restored calcium entry in G82D cells. Our results suggest that the calcium entry pathway is blocked by sphingosine and that activation of SK1 and the production of S1P, through an autocrine mechanism, facilitate calcium entry through activation of S1P receptor 2. This is a novel mechanism by which the sphingosine-S1P rheostat regulates cellular calcium homeostasis.

scholarly journals The effect of endotoxin on functional parameters of mammary CID-9 cells

Reproduction ◽  
2004 ◽  
Vol 127 (3) ◽  
pp. 397-406 ◽  
Author(s):  
B Safieh-Garabedian ◽  
G M Mouneimne ◽  
W El-Jouni ◽  
M Khattar ◽  
R Talhouk
Keyword(s):  
Active Form ◽  
Nuclear Factor Κb ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Gelatinase Activity ◽  
Functional Parameters ◽  
Nuclear Extracts ◽  
Cell Growth And Viability ◽  
Factor Α ◽  
In Cells

The effect of endotoxin on mammary CID-9 cells, which differentiate in culture and express β-casein, was investigated. Cells in culture supplemented with lactogenic hormones and dripped with EMS-Matrix (EMS-drip), were treated daily with endotoxin (0.5–500 μg/ml). Endotoxin at concentrations of less or equal to 10 μg/ml did not affect cell growth and viability up to 5 days post endotoxin treatment. Endotoxin (0.01–10 μg/ml) was added to the culture medium, upon confluence, and functional parameters were examined within 48 h post endotoxin treatment. Nuclear factor-κB (NF-κB) (p52) increased in nuclear extracts from endotoxin-stimulated cells within 1 h of treatment, while β-casein mRNA and protein expression decreased in a concentration-dependent manner at 24 and 48 h post treatment. Zymography showed that the 72 and 92 kDa gelatinase activity increased in cells at 24 and 48 h post endotoxin treatment at 10 and 50 μg/ml. At the latter concentration, the active form of 72 kDa gelatinase was induced at 48 h. Interleukin-6 and tumor necrosis factor-α levels increased at 1–3 h post endotoxin treatment and peaked at 6 h in cells on plastic and EHS-drip. Nerve growth factor (NGF) levels increased in control and endotoxin-treated cells in a time-dependent manner, and endotoxin increased NGF levels in culture at 6 and 9 h post endotoxin treatment. This study shows that endotoxin activated NF-κB, suppressed β-casein expression and upregulated gelatinases, cytokines and NGF. This model could be used to investigate the role of mammary cells in initiating and propagating inflammation and to test candidate molecules for potential anti-inflammatory properties.

Dual-specific Src and Abl kinase inhibitors, PP1 and CGP76030, inhibit growth and survival of cells expressing imatinib mesylate–resistant Bcr-Abl kinases

Blood ◽  
2003 ◽  
Vol 101 (2) ◽  
pp. 664-672 ◽  
Author(s):  
Markus Warmuth ◽  
Nicola Simon ◽  
Olga Mitina ◽  
Ruth Mathes ◽  
Doriano Fabbro ◽  
...  
Keyword(s):  
Imatinib Mesylate ◽  
Kinase Inhibitors ◽  
Clonal Evolution ◽  
Src Kinase ◽  
Dependent Manner ◽  
Binding Modes ◽  
Concentration Dependent Manner ◽  
Growth And Survival ◽  
Abl Kinase ◽  
In Cells

The leukemogenic tyrosine kinase Bcr-Abl contains a highly conserved inhibitor-binding pocket (IBP), which serves as a binding site for imatinib mesylate. Mutations at the IBP may lead to resistance of the Abl kinase against imatinib mesylate. To examine the mechanisms of imatinib mesylate binding and resistance in more detail, we created several point mutations at amino acid positions 315 and 380 of Abl, blocking the access to the IBP and rendering Bcr-Abl imatinib mesylate–resistant. Moreover, introduction of a mutation destabilizing the inactive conformation of Abl (Asp276Ser/Glu279Ser) also led to imatinib mesylate resistance, suggesting that the inhibitor required inactivation of the kinase prior to binding. These Bcr-Abl mutants were then used to evaluate the binding mode and specificity of 2 compounds, PP1 and CGP76030, originally characterized as Src kinase inhibitors. Both compounds inhibited Bcr-Abl in a concentration-dependent manner by overlapping binding modes. However, in contrast to imatinib mesylate, PP1 and CGP76030 blocked cell growth and survival in cells expressing various inhibitor-resistant Abl mutants. Studies on the potential signaling mechanisms demonstrated that in cells expressing inhibitor-resistant Bcr-Abl mutants, PP1 and CGP76030 inhibited the activity of Src family tyrosine kinases and Akt but not signal transducer and activator of transcription–5 (STAT5) and JUN kinase (Jnk). The results suggest that the use of Src kinase inhibitors is a potential strategy to prevent or overcome clonal evolution of imatinib mesylate resistance in Bcr-Abl+ leukemia.

scholarly journals Stimulation of plasmin activity by oleic acid

1992 ◽  
Vol 282 (3) ◽  
pp. 863-866 ◽  
Author(s):  
A A R Higazi ◽  
Z Finci-Yeheskel ◽  
A A R Samara ◽  
R Aziza ◽  
M Mayer
Keyword(s):  
Oleic Acid ◽  
Binding Sites ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Plasmin Activity ◽  
Concentration Dependent Manner ◽  
Acid Analogue ◽  
Kinetic Pattern ◽  
Fold Stimulation ◽  
Stimulation Of

The amidolytic activity of plasmin with the chromogenic substrate H-D-valyl-L-leucyl-L-lysine p-nitroanilide (S-2251) is stimulated by oleic acid in a dose-dependent and saturable fashion. The activity of plasmin on S-2251 in the presence of oleic acid followed a sigmoidal kinetic pattern, with an almost 4-fold stimulation of activity at 60 microM-oleic acid. Half-maximal stimulation occurred at an oleic acid level of 19.5 microM. The amino acid analogue 6-aminohexanoic acid (AHA), which is known to bind to lysine-binding sites in plasmin, suppressed the stimulatory effect of oleic acid in a concentration-dependent manner; at 0.3 mM-AHA, about 70% of the oleic acid-dependent enhancement of plasmin activity was abolished. The l/v versus 1/[S] plot for plasmin changed in the presence of oleic acid from a linear to a non-linear curve, suggesting positive co-operativity. 14C-labelled oleic acid bound to plasmin, and the bound ligand was displaced by an excess of unlabelled oleic acid. Oleic acid also produced a marked (40-fold) stimulation of the plasminogen-dependent cleavage of S-2251 by urokinase. A half-maximal effect on plasminogen activation was obtained at 40 microM-oleic acid. The present findings suggest that the ability of oleic acid to stimulate plasmin activity and to enhance the conversion of plasminogen to plasmin depends on the interaction of oleic acid with specific lysine-binding sites in plasmin.

scholarly journals Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ruslana Vasylkovska ◽  
Natalia Petriv ◽  
Halyna Semchyshyn
Keyword(s):  
Hydrogen Peroxide ◽  
Growth Medium ◽  
Carbon Sources ◽  
Carbon Substrate ◽  
Dependent Manner ◽  
Yeast Growth ◽  
Concentration Dependent Manner ◽  
Reproductive Ability ◽  
The Relationship ◽  
Hormetic Response

Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response inS. cerevisiaeand carbon sources in yeast growth medium. In general, our data indicate that (i) hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii) the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii) metabolic and growth rates as well as catalase activity play an important role in H2O2-induced hormetic response in yeast.

scholarly journals Comparative Intracellular (THP-1 Macrophage) and Extracellular Activities of β-Lactams, Azithromycin, Gentamicin, and Fluoroquinolones against Listeria monocytogenes at Clinically Relevant Concentrations

2002 ◽  
Vol 46 (7) ◽  
pp. 2095-2103 ◽  
Author(s):  
Stéphane Carryn ◽  
Françoise Van Bambeke ◽  
Marie-Paule Mingeot-Leclercq ◽  
Paul M. Tulkens
Keyword(s):  
Listeria Monocytogenes ◽  
Conventional Therapy ◽  
The Other ◽  
Intracellular Bacteria ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cellular Accumulation ◽  
Intracellular Activities ◽  
The Difference ◽  
In Cells

ABSTRACT The activities of ampicillin, meropenem, azithromycin, gentamicin, ciprofloxacin, and moxifloxacin against intracellular hemolysin-positive Listeria monocytogenes were measured in human THP-1 macrophages and were compared with the extracellular activities observed in broth. All extracellular concentrations were adjusted to explore ranges that are clinically achievable in human serum upon conventional therapy. In broth, ampicillin, meropenem, and azithromycin were only bacteriostatic, whereas gentamicin, ciprofloxacin, and moxifloxacin were strongly bactericidal in a concentration-dependent manner. In cells, ampicillin, meropenem, azithromycin, and ciprofloxacin were slightly bactericidal (0.3- to 0.8-log CFU reductions), moxifloxacin was strongly bactericidal (2.1-log CFU reduction), and gentamicin was virtually inactive. The difference in the efficacies of moxifloxacin and ciprofloxacin in cells did not result from a difference in levels of accumulation in cells (6.96 ± 1.05 versus 7.75 ± 1.03) and was only partially explainable by the difference in the MICs (0.58 ± 0.04 versus 1.40 ± 0.17 mg/liter). Further analysis showed that intracellular moxifloxacin expressed only approximately 1/7 of the activity demonstrated against extracellular bacteria and ciprofloxacin expressed only 1/15 of the activity demonstrated against extracellular bacteria. Gentamicin did not increase the intracellular activities of the other antibiotics tested. The data suggest (i) that moxifloxacin could be of potential interest for eradication of the intracellular forms of L. monocytogenes, (ii) that the cellular accumulation of an antibiotic is not the only determinant of its intracellular activity (for fluoroquinolones, it is actually a self-defeating process as far as activity is concerned), and (iii) that pharmacodynamics (activity-to-concentration relationships) need to be considered for the establishment of efficacy against intracellular bacteria, just as they are for the establishment of efficacy against extracellular infections.

scholarly journals Regulatory effects of gallium on transferrin-independent iron uptake by human leukemic HL60 cells

Blood ◽  
1992 ◽  
Vol 80 (2) ◽  
pp. 505-511 ◽  
Author(s):  
CR Chitambar ◽  
D Sax
Keyword(s):  
Cell Membrane ◽  
Cellular Uptake ◽  
Iron Uptake ◽  
Cellular Proliferation ◽  
Gallium Nitrate ◽  
Uptake System ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Hl60 Cells ◽  
Stimulation Of

Gallium, a pharmacologically important metal, resembles iron with respect to transferrin (Tf) binding and Tf receptor-mediated cellular uptake. In the present study, we examined the effect of gallium on Tf- independent iron uptake by HL60 cells. In contrast to the inhibitory effect of Tf-gallium on Tf-iron uptake, gallium nitrate, in a time-, temperature-, and concentration-dependent manner, stimulated Tf- independent uptake of iron-nitrilotriacetic acid (Fe-NTA). Preexposure of cells to gallium followed by removal of gallium also resulted in sustained stimulation of iron uptake. The anti-Tf receptor monoclonal antibody 42/6 blocked Tf-iron uptake, but had no effect on gallium- induced stimulation of Tf-independent iron uptake. Gallium increased the number of cell membrane iron-binding sites, without a change in their affinity for iron. Ferric chloride stimulated Tf-independent gallium uptake. Although gallium nitrate inhibited cell growth in Tf- free medium, cellular proliferation was restored by Fe-NTA. Gallium and iron appear to share the same Tf-independent cellular uptake system in HL60 cells. Exposure of cells to gallium results in the activation of cell membrane non-Tf iron carriers that may play a role in overcoming the Tf-independent growth-inhibitory effects of gallium.

scholarly journals Erythrocytes of Little Ground Squirrels Undergo Reversible Oxidative Stress During Arousal From Hibernation

2021 ◽  
Vol 12 ◽  
Author(s):  
Nisred K. Klichkhanov ◽  
Elena R. Nikitina ◽  
Zainab M. Shihamirova ◽  
Maria D. Astaeva ◽  
Shamil I. Chalabov ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Body Temperature ◽  
Membrane Lipids ◽  
Ground Squirrels ◽  
The Body ◽  
Oxidative Modification ◽  
Dependent Manner ◽  
Maximum Increase ◽  
Concentration Dependent Manner ◽  
In Cells

The hibernation of small mammals is characterized by long torpor bouts alternating with short periods of arousal. During arousal, due to a significant increase in oxygen consumption, tissue perfusion, and the launch of thermogenesis in cells, a large amount of reactive oxygen species (ROS) and nitrogen (RNS) can be formed, which can trigger oxidative stress in cells. To estimate this possibility, we studied the intensity of free-radical processes in the red blood cells (RBCs) of little ground squirrels (LGS; Spermophilus pygmaeus) in the dynamics of arousal from hibernation. We found that in the torpid state, the degree of generation of ROS and RNS (8.3%, p>0.09; 20.7%, p<0.001, respectively), the degree of oxidative modification of membrane lipids and RBC proteins is at a low level (47%, p<0.001; 82.7%, p<0.001, respectively) compared to the summer control. At the same time, the activity of superoxide dismutase (SOD) and catalase (CAT) in RBC is significantly reduced (32.8%, p<0.001; 22.2%, p<0.001, respectively), but not the level of glutathione (GSH). In the torpid state, SOD is activated by exogenous GSH in concentration-dependent manner, which indicates reversible enzyme inhibition. During the arousal of ground squirrels, when the body temperature reaches 25°C, RBCs are exposed oxidative stress. This is confirmed by the maximum increase in the level of uric acid (25.4%, p<0.001) in plasma, a marker of oxidative modification of lipids [thiobarbituric acid reactive substances (TBARS); 82%, p < 0.001] and proteins (carbonyl groups; 499%, p < 0.001) in RBC membranes, as well as the decrease in the level of GSH (19.7%, p < 0.001) in erythrocytes relative to the torpid state and activity of SOD and CAT in erythrocytes to values at the Tb 20°C. After full recovery of body temperature, the level of GSH increases, the ratio of SOD/CAT is restored, which significantly reduces the degree of oxidative damage of lipids and proteins of RBC membranes. Thus, the oxidative stress detected at Tb 25°C was transient and physiologically regulated.

Anemone altaica Induces Apoptosis in Human Osteosarcoma Cells

2015 ◽  
Vol 43 (05) ◽  
pp. 1031-1042 ◽  
Author(s):  
I-Chang Chang ◽  
Tsay-I Chiang ◽  
Chun Lo ◽  
Yi-Hua Lai ◽  
Chia-Herng Yue ◽  
...  
Keyword(s):  
Cellular Proliferation ◽  
Therapeutic Drug ◽  
Related Factor ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Related Factors ◽  
Apoptotic Pathway ◽  
Concentration Dependent Manner ◽  
Human Osteosarcoma Cells ◽  
U2os Cells

In the past decade, no significant improvement has been made in chemotherapy for osteosarcoma (OS). To develop improved agents against OS, we screened 70 species of medicinal plants and treated two human OS cell lines with different agent concentrations. We then examined cell viability using the MTT assay. Results showed that a candidate plant, particularly the rhizomes of Anemone altaica Fisch. ex C. A. Mey aqueous extract (AAE), suppressed the viability of HOS and U2OS cells in a concentration-dependent manner. Flow cytometry analysis revealed that AAE significantly increased the amount of cell shrinkage (Sub-G1 fragments) in HOS and U2OS cells. Moreover, AAE increased cytosolic cytochrome c and Bax, but decreased Bcl-2. The amount of cleaved caspase-3 and poly-(ADP-ribose) polymerase-1 (PARP-1) were significantly increased. AAE suppressed the growth of HOS and U2OS through the intrinsic apoptotic pathway. Data suggest that AAE is cytotoxic to HOS and U2OS cells and has no significant influence on human osteoblast hFOB cells. The high mRNA levels of apoptosis-related factors (PPP1R15A, SQSTM1, HSPA1B, and DDIT4) and cellular proliferation markers (SKA2 and BUB1B) were significantly altered by the AAE treatment of HOS and U2OS cells. Results show that the anticancer activity of AAE could up-regulate the expression of a cluster of genes, especially those in the apoptosis-related factor family and caspase family. Thus, AAE has great potential as a useful therapeutic drug for human OS.

scholarly journals Saffron and Its Major Ingredients’ Effect on Colon Cancer Cells with Mismatch Repair Deficiency and Microsatellite Instability

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3855
Author(s):  
Amr Amin ◽  
Aaminah Farrukh ◽  
Chandraprabha Murali ◽  
Akbar Soleimani ◽  
Françoise Praz ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Mismatch Repair ◽  
Cell Lines ◽  
Cellular Proliferation ◽  
Cell Types ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Colon Cells ◽  
Therapeutic Implications ◽  
Crude Extracts

Background: Colorectal cancer (CRC) is one of the most common cancers worldwide. One of its subtypes is associated with defective mismatch repair (dMMR) genes. Saffron has many potentially protective roles against colon malignancy. However, these roles in the context of dMMR tumors have not been explored. In this study, we aimed to investigate the effects of saffron and its constituents in CRC cell lines with dMMR. Methods: Saffron crude extracts and specific compounds (safranal and crocin) were used in the human colorectal cancer cell lines HCT116, HCT116+3 (inserted MLH1), HCT116+5 (inserted MSH3), and HCT116+3+5 (inserted MLH1 and MSH3). CDC25b, p-H2AX, TPDP1, and GAPDH were analyzed by Western blot. Proliferation and cytotoxicity were analyzed by MTT. The scratch wound assay was also performed. Results: Saffron crude extracts restricted (up to 70%) the proliferation in colon cells with deficient MMR (HCT116) compared to proficient MMR. The wound healing assay indicates that deficient MMR cells are doing better (up to 90%) than proficient MMR cells when treated with saffron. CDC25b and TDP1 downregulated (up to 20-fold) in proficient MMR cells compared to deficient MMR cells, while p.H2AX was significantly upregulated in both cell types, particularly at >10 mg/mL saffron in a concentration-dependent manner. The reduction in cellular proliferation was accompanied with upregulation of caspase 3 and 7. The major active saffron compounds, safranal and crocin reproduced most of the saffron crude extracts’ effects. Conclusions: Saffron’s anti-proliferative effect is significant in cells with deficient MMR. This novel effect may have therapeutic implications and benefits for MSI CRC patients who are generally not recommended for the 5-fluorouracil-based treatment.

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