Effects of Ca2+ and Mg2+ on ATP-dependent 45Ca2+ influx in A-431 human epidermoidal carcinoma cells

1991 ◽  
Vol 69 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Kenji Sugita ◽  
Kazuo Hosoi ◽  
Yoshimi Shioda ◽  
Takao Ueha
Keyword(s):  
Calcium Ions ◽  
Calcium Influx ◽  
Inositol Trisphosphate ◽  
Cytosolic Calcium ◽  
Carcinoma Cells ◽  
Dependent Manner ◽  
Parallel Effect ◽  
Intracellular Calcium Ion ◽  
Preincubation Medium ◽  
In Cells

Upon stimulation with 10−6–10−3 M ATP, A-431 human epidermoidal carcinoma cells incorporated radioactive calcium from their medium in a temperature-dependent manner. The rate of incorporation of 45Ca2+ was rapid for the initial 5 min, but decreased immediately thereafter. The preincubation of cells for 2 h in medium depleted of both Ca2+ and Mg2+ abolished the ATP-dependent 45Ca2+ incorporation, irrespective of whether or not the subsequent incubation medium contained Mg2+ ions. ATP-dependent 45Ca2+ incorporation could be restored by a second preincubation (1 h) in medium containing 1 mM Mg2+, but no Ca2+. The Mg2+ ions in the second preincubation medium could be replaced by Ca2+, Co2+, or Cu2+ for restoration of such activity. Elevation of inositol trisphosphate (InsP3) was observed in cells depleted of either Ca2+ or Mg2+, but not in cells depleted of both ions. A parallel effect was observed in changes in [Ca2+]i. Since the concentration of cytosolic calcium ions does not change by incubation of cells in medium depleted of and (or) restored with calcium ions, we conclude that either calcium or magnesium ions associated with some cellular component(s) are responsible for production of InsP3, which then supposedly mobilizes Ca2+ and provokes 45Ca2+ influx.Key words: intracellular calcium ion, inositol trisphosphate, calcium influx.

Calcium ions and tyrosine phosphorylation interact coordinately with actin to regulate cytoprotective responses to stretching

1997 ◽  
Vol 110 (1) ◽  
pp. 11-21 ◽  
Author(s):  
M. Glogauer ◽  
P. Arora ◽  
G. Yao ◽  
I. Sokholov ◽  
J. Ferrier ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Calcium Ions ◽  
Calcium Influx ◽  
Magnetic Bead ◽  
Mechanical Stimuli ◽  
Filamentous Actin ◽  
Cortical Actin ◽  
Force Application ◽  
Membrane Rigidity ◽  
In Cells

The actin-dependent sensory and response elements of stromal cells that are involved in mechanical signal transduction are poorly understood. To study mechanotransduction we have described previously a collagen-magnetic bead model in which application of well-defined forces to integrins induces an immediate (< 1 second) calcium influx. In this report we used the model to determine the role of calcium ions and tyrosine-phosphorylation in the regulation of force-mediated actin assembly and the resulting change in membrane rigidity. Collagen-beads were bound to cells through the focal adhesion-associated proteins talin, vinculin, alpha 2-integrin and beta-actin, indicating that force application was mediated through cytoskeletal elements. When force (2 N/m2) was applied to collagen beads, confocal microscopy showed a marked vertical extension of the cell which was counteracted by an actin-mediated retraction. Immunoblotting showed that force application induced F-actin accumulation at the bead-membrane complex but vinculin, talin and alpha 2-integrin remained unchanged. Atomic force microscopy showed that membrane rigidity increased 6-fold in the vicinity of beads which had been exposed to force. Force also induced tyrosine phosphorylation of several cytoplasmic proteins including paxillin. The force-induced actin accumulation was blocked in cells loaded with BAPTA/AM or in cells preincubated with genistein, an inhibitor of tyrosine phosphorylation. Repeated force application progressively inhibited the amplitude of force-induced calcium ion flux. As force-induced actin reorganization was dependent on calcium and tyrosine phosphorylation, and as progressive increases of filamentous actin in the submembrane cortex were correlated with increased membrane rigidity and dampened calcium influx, we suggest that cortical actin regulates stretch-activated cation permeable channel activity and provides a desensitization mechanism for cells exposed to repeated long-term mechanical stimuli. The actin response may be cytoprotective since it counteracts the initial force-mediated membrane extension and potentially strengthens cytoskeletal integrity at force-transfer points.

Prevention of Copper-Induced Calcium Influx and Cell Death by Prion-Derived Peptide in Suspension-Cultured Tobacco Cells

2009 ◽  
Vol 64 (5-6) ◽  
pp. 411-417 ◽  
Author(s):  
Tomoko Kagenishi ◽  
Ken Yokawa ◽  
Masaki Kuse ◽  
Minoru Isobe ◽  
François Bouteau ◽  
...  
Keyword(s):  
Cell Death ◽  
Calcium Influx ◽  
Plant Cells ◽  
Cytosolic Calcium ◽  
Calcium Signal ◽  
Channel Blockers ◽  
Dependent Manner ◽  
Copper Binding ◽  
Channel Opening ◽  
Nicotiana Tabacum L

Impact of copper on the oxidative and calcium signal transductions leading to cell death in plant cells and the effects of the copper-binding peptide derived from the human prion protein (PrP) as a novel plant-protecting agent were assessed using a cell suspension culture of transgenic tobacco (Nicotiana tabacum L., cell line BY-2) expressing the aequorin gene. Copper induces a series of biological and chemical reactions in plant cells including the oxidative burst reflecting the production of reactive oxygen species (ROS), such as hydroxyl radicals, and stimulation of calcium channel opening, allowing a transient increase in cytosolic calcium concentrations. The former was proven by the action of specifiC ROS scavengers blocking the calcium responses and the latter was proven by an increase in aequorin luminescence and its inhibition by specifi c channel blockers. Following these early events completed within 10 min, the development of copper-induced cell death was observed during additional 1 h in a dose-dependent manner. Addition of a synthetic peptide (KTNMKHMA) corresponding to the neurotoxic sequence in human PrP, prior to the addition of copper, effectively blocked both calcium influx and cell death induced by copper. Lastly, a possible mechanism of peptide action and future applications of this peptide in the protection of plant roots from metal toxicity or in favour of phytoremediation processes are discussed

scholarly journals Role of nonselective cation channels in spontaneous and protein kinase A-stimulated calcium signaling in pituitary cells

2011 ◽  
Vol 301 (2) ◽  
pp. E370-E379 ◽  
Author(s):  
Melanija Tomić ◽  
Marek Kucka ◽  
Karla Kretschmannova ◽  
Shuo Li ◽  
Maria Nesterova ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Electrical Activity ◽  
Calcium Signaling ◽  
Calcium Influx ◽  
Cation Channels ◽  
Pituitary Cells ◽  
Dependent Manner ◽  
Nonselective Cation Channels ◽  
In Cells

Several receptors linked to the adenylyl cyclase signaling pathway stimulate electrical activity and calcium influx in endocrine pituitary cells, and a role for an unidentified sodium-conducting channel in this process has been proposed. Here we show that forskolin dose-dependently increases cAMP production and facilitates calcium influx in about 30% of rat and mouse pituitary cells at its maximal concentration. The stimulatory effect of forskolin on calcium influx was lost in cells with inhibited PKA (cAMP-dependent protein kinase) and in cells that were haploinsufficient for the main PKA regulatory subunit but was preserved in cells that were also haploinsufficient for the main PKA catalytic subunit. Spontaneous and forskolin-stimulated calcium influx was present in cells with inhibited voltage-gated sodium and hyperpolarization-activated cation channels but not in cells bathed in medium, in which sodium was replaced with organic cations. Consistent with the role of sodium-conducting nonselective cation channels in PKA-stimulated Ca2+ influx, cAMP induced a slowly developing current with a reversal potential of about 0 mV. Two TRP (transient receptor potential) channel blockers, SKF96365 and 2-APB, as well as flufenamic acid, an inhibitor of nonselective cation channels, also inhibited spontaneous and forskolin-stimulated electrical activity and calcium influx. Quantitative RT-PCR analysis indicated the expression of mRNA transcripts for TRPC1 >> TRPC6 > TRPC4 > TRPC5 > TRPC3 in rat pituitary cells. These experiments suggest that in pituitary cells constitutively active cation channels are stimulated further by PKA and contribute to calcium signaling indirectly by controlling the pacemaking depolarization in a sodium-dependent manner and directly by conducting calcium.

scholarly journals Adenosine Triphosphate-Evoked Cytosolic Calcium Oscillations in Human Granulosa-Luteal Cells: Role of Protein Kinase C1

2001 ◽  
Vol 86 (2) ◽  
pp. 773-777 ◽  
Author(s):  
Chen-Jei Tai ◽  
Sung Keun Kang ◽  
Peter C. K. Leung
Keyword(s):  
Protein Kinase ◽  
Calcium Influx ◽  
Purinergic Receptor ◽  
Cytosolic Calcium ◽  
Inhibitory Effect ◽  
Calcium Oscillations ◽  
Dependent Manner ◽  
Luteal Cells

ATP has been shown to modulate progesterone production in human granulosa-luteal cells (hGLCs) in vitro. After binding to a G protein-coupled P2 purinergic receptor, ATP stimulates phospholipase C. The resultant production of diacylglycerol and inositol triphosphate activates protein kinase C (PKC) and intracellular calcium [Ca2+]i mobilization, respectively. In the present study, we examined the potential cross-talk between the PKC and Ca2+ pathway in ATP signal transduction. Specifically, the effect of PKC on regulating ATP-evoked[ Ca2+]i oscillations were examined in hGLCs. Using microspectrofluorimetry, [Ca2+]i oscillations were detected in Fura-2 loaded hGLCs in primary culture. The amplitudes of the ATP-triggered [Ca2+]i oscillations were reduced in a dose-dependent manner by pretreating the cells with various concentrations (1 nm to 10μ m) of the PKC activator, phorbol-12-myristate-13-acetate (PMA). A 10 μm concentration of PMA completely suppressed 10 μm ATP-induced oscillations. The inhibitory effect occurred even when PMA was given during the plateau phase of ATP evoked [Ca2+]i oscillations, suggesting that extracellular calcium influx was inhibited. The role of PKC was further substantiated by the observation that, in the presence of a PKC inhibitor, bisindolylmaleimide I, ATP-induced[ Ca2+]i oscillations were not completely suppressed by PMA. Furthermore, homologous desensitization of ATP-induced calcium oscillations was partially reversed by bisindolylmaleimide I, suggesting that activated PKC may be involved in the mechanism of desensitization. These results demonstrate that PKC negatively regulates the ATP-evoked [Ca2+]i mobilization from both intracellular stores and extracellular influx in hGLCs and further support a modulatory role of ATP and P2 purinoceptor in ovarian steroidogenesis.

scholarly journals Role of leukemia inhibitor factor (LIF) in decidualisation of murine uterine stromal cells in vitro

2004 ◽  
Vol 181 (3) ◽  
pp. 477-492 ◽  
Author(s):  
AA Fouladi Nashta ◽  
CV Andreu ◽  
N Nijjar ◽  
JK Heath ◽  
SJ Kimber
Keyword(s):  
In Vitro Culture ◽  
Stromal Cells ◽  
Control Level ◽  
Calf Serum ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Alp Activity ◽  
Dose Dependent ◽  
In Cells

Decidualisation of uterine stromal cells is a prerequisite for implantation of the embryo in mice. Here we have used an in vitro culture system in which stromal cells decidualise as indicated by a number of markers, including an increase in alkaline phosphatase (ALP) activity. The latter was used as a quantitative marker of decidualisation in the presence of low (2%) fetal calf serum. Prostaglandin E(2) (PGE(2)), which is known to induce decidualisation, increased ALP activity, and this effect was blocked in a dose-dependent manner by indomethacin. Leukemia inhibitory factor (LIF) was then examined, but it had no effect on PGE(2) secretion. However, LIF suppressed ALP activity in a dose-dependent manner in the presence of 2% serum, while an inhibitor of LIF that competes for binding to its receptor reversed the effect of LIF and increased ALP activity above the control level. In serum-free cultures, stromal cells differentiated rapidly, and no differences were observed between LIF-treated and untreated cultures. Stromal cells produce LIF during in vitro culture, and this peaked at 48 h. Freshly collected stromal cells from both day-2 and -4 pregnant mice expressed mRNA for the LIF receptor, and the transcript level was higher in cells isolated on day 4. However, no differences were observed in the relative levels of transcripts in cells from day 2 and day 4 after culture, nor were there differences between the LIF-treated cultures and controls. Therefore, in this study, we have shown that LIF suppresses decidualisation of murine uterine stromal cells in the presence of serum, this is not due to the regulation of PGE(2) secretion by stromal cells.

scholarly journals RASSF1A inhibits PDGFB-driven malignant phenotypes of nasopharyngeal carcinoma cells in a YAP1-dependent manner

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Ying-Ying Liang ◽  
Xu-Bin Deng ◽  
Xian-Tao Lin ◽  
Li-Li Jiang ◽  
Xiao-Ting Huang ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Underlying Mechanism ◽  
Carcinoma Cells ◽  
Dependent Manner ◽  
Transcriptional Coactivator ◽  
Actin Remodeling ◽  
Aggressive Tumor ◽  
Subunit B

Abstract Nasopharyngeal carcinoma (NPC) is a highly aggressive tumor characterized by distant metastasis. Deletion or down-regulation of the tumor suppressor protein ras-association domain family protein1 isoform A (RASSF1A) has been confirmed to be a key event in NPC progression; however, little is known about the effects or underlying mechanism of RASSF1A on the malignant phenotype. In the present study, we observed that RASSF1A expression inhibited the malignant phenotypes of NPC cells. Stable silencing of RASSF1A in NPC cell lines induced self-renewal properties and tumorigenicity in vivo/in vitro and the acquisition of an invasive phenotype in vitro. Mechanistically, RASSF1A inactivated Yes-associated Protein 1 (YAP1), a transcriptional coactivator, through actin remodeling, which further contributed to Platelet Derived Growth Factor Subunit B (PDGFB) transcription inhibition. Treatment with ectopic PDGFB partially increased the malignancy of NPC cells with transient knockdown of YAP1. Collectively, these findings suggest that RASSF1A inhibits malignant phenotypes by repressing PDGFB expression in a YAP1-dependent manner. PDGFB may serve as a potential interest of therapeutic regulators in patients with metastatic NPC.

scholarly journals Orientia tsutsugamushi Inhibits Apoptosis of Macrophages by Retarding Intracellular Calcium Release

2002 ◽  
Vol 70 (8) ◽  
pp. 4692-4696 ◽  
Author(s):  
Mee-Kyung Kim ◽  
Seung-Yong Seong ◽  
Ju-Young Seoh ◽  
Tae-Hee Han ◽  
Hyeon-Je Song ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Calcium Concentration ◽  
Calcium Release ◽  
Cytosolic Calcium ◽  
Orientia Tsutsugamushi ◽  
Cytosolic Calcium Concentration ◽  
Infected Cells ◽  
Intracellular Calcium Release ◽  
Calcium Redistribution ◽  
In Cells

ABSTRACT Orientia tsutsugamushi shows both pro- and antiapoptotic activities in infected vertebrate cells. Apoptosis of THP-1 cells induced by beauvericin was inhibited by O. tsutsugamushi infection. Beauvericin-induced calcium redistribution was significantly reduced and retarded in cells infected with O. tsutsugamushi. Antiapoptotic activities of O. tsutsugamushi in infected cells are most probably due to inhibition of the increase in the cytosolic calcium concentration.

Protective effect of adenosine against a calcium paradox in the isolated frog heart

1992 ◽  
Vol 70 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Maria Touraki ◽  
Antigone Lazou
Keyword(s):  
Protective Effect ◽  
Calcium Influx ◽  
Calcium Paradox ◽  
Mechanical Activity ◽  
Frog Heart ◽  
Dependent Manner ◽  
Myocardial Cells ◽  
Tissue Calcium ◽  
Maximum Protection ◽  
Dose Dependent

The effect of adenosine on the calcium paradox in the isolated frog heart was studied. Addition of adenosine during calcium depletion protected the frog heart against a calcium paradox. This protective effect was indicated by reduced protein and creatine kinase release, maintenance of electrical activity, and recovery of mechanical activity during reperfusion. Tissue calcium determination results showed that adenosine protected frog myocardial cells by reducing the massive calcium influx during reperfusion possibly through an action on calcium channels. Adenosine exerted its action in a dose-dependent manner; a concentration of 10 μM adenosine provided maximum protection of myocardial cells against the calcium paradox damage. Higher concentrations of adenosine produced side effects on both electrical and mechanical activity. These results are discussed in terms of the possible mechanism involved in the protective effect of adenosine.Key words: calcium paradox, adenosine, frog heart.

Sevoflurane but not propofol provided dual effects of cell survival in human neuroblastoma SH-SY5Y cells

2021 ◽  
Vol 18 ◽  
Author(s):  
Xue Gao ◽  
Xiu Wang ◽  
Lei Zhang ◽  
Ge Liang ◽  
Rachel Mund ◽  
...  
Keyword(s):  
Cell Survival ◽  
Prolonged Exposure ◽  
Calcium Influx ◽  
Cell Damage ◽  
Cytosolic Calcium ◽  
Extracellular Calcium ◽  
Mitochondrial Calcium ◽  
General Anesthetics ◽  
Wild Type ◽  
Human Neuroblastoma

Background: We have hypothesized that the most commonly used intravenous (propofol) and inhalational (sevoflurane) general anesthetics affect cell survival concentration and duration dependently with different potency associated with their differential potency to affect intracellular calcium homeostasis. Methods: Human neuroblastoma SH-SY5Y cells stably transfected with either wild type or M146L mutant human presenilin 1 were cultured and exposed to equipotent of propofol or sevoflurane. Cell viability, cytosolic and mitochondrial calcium were measured. Results: Sevoflurane but not propofol, at clinically relevant concentrations and durations, promoted cell survival. Prolonged exposure (24 hours) of 1% sevoflurane resulted in significant cell damage in both types of cells. Both sevoflurane and propofol had significantly higher cell response rates to the elevation of cytosolic calcium or mitochondrial calcium in the presence of extracellular calcium. With the contribution of calcium influx, sevoflurane but not equipotent 1 MAC propofol, caused a significantly greater increase in peak and overall calcium in Alzheimer’s mutation cell than in wild type cells, but significantly more increase in overall mitochondrial calcium concentrations in wild type than mutation cells. In the absence of extracellular calcium influx, sevoflurane, but not propofol, caused more significant elevations of overall mitochondrial calcium concentration in mutation cells than control cells. Conclusion: Calcium influx contributed to the general anesthetics mediated elevation of cytosolic or mitochondrial calcium, which is especially true for propofol. Sevoflurane has a greater potency to either promote or inhibit cell survival than propofol, which may be associated with its ability to affect cytosolic or mitochondrial calcium.

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