Disease relevance of calcein

• On exposure to Sendai virus and mild hypo-osmotic stress, vesicles of the appropriate composition released a significant portion of their internal contents, as indicated by an increase in calcein fluorescence [1].
• ADCC against LA-N-1 human neuroblastoma cells was evaluated with 4-hour calcein acetoxymethyl ester (calcein-AM) microcytotoxicity assay, electron microscopy, and multi-parameter flow cytometry [2].
• Calcein-labeled B16 melanoma (B16M) cells were injected intraportally, and in vivo video microscopy was used to study the distribution and damage of cancer cells arrested in the liver microvasculature over a period of 4 hours [3].
• As calcein permeated, growth of blebs on the plasma membrane accelerated [4].
• In an in vitro model system with HepG2 cells, the effects of ESRD serum on the labile iron pool (LIP) were assayed using the fluorescence calcein assay [5].

High impact information on calcein

• This phenomenon was ascribed to MPT induction because (a) bongkrekic acid prevented it and (b) mitochondria became permeable for calcein ( approximately 620 daltons) concurrently with depolarization [6].
• Consistent with these data, addition of IL-7 to neonatal calvarial organ cultures blocked new bone formation, and injection of IL-7 into mice in vivo inhibited bone formation as measured by calcein incorporation into long bones [7].
• Daily injections of synthetic parathyroid hormone for 30 days increased calcein-surface labeling in wild-type but caused no further increase in the already high calcein staining of Col1a1(r/r) bones [8].
• Calcein-labeled T cells were used to assay HIF adhesion and Transwell HIMEC transmigration [9].
• Cell to cell diffusion of calcein was poor among Cx43-deficient osteoblasts, whose differentiated phenotypic profile and mineralization potential were greatly impaired, compared with wild-type cells [10].

Chemical compound and disease context of calcein

• Vesicles were constituted with glycophorin, the Sendai virus receptor of human erythrocytes, and loaded with calcein, a polar derivative of fluorescein, at self-quenching concentrations [1].
• Cultured human osteosarcoma cells (143B TK-) stained with JC-1, MitoTracker dyes, or calcein plus Co2+ were imaged by confocal microscopy to visualize changes of mitochondrial membrane potential (DeltaPsim), morphology, and permeability transition, respectively, during treatment with a protonophore, carbonyl cyanide m-chlorophenylhydrazone (CCCP) [11].
• Sendai virus induced liposome leakage has been studied by using liposomes containing a self-quenching fluorescent dye, calcein [12].
• Human colon adenocarcinoma (Caco-2) and human blood-brain barrier endothelial cells were transfected or transduced to express Pgp, and the uptake of rhodamine123, calcein AM, or daunorubicin was measured by flow cytometry in the presence of the drugs [13].
• The results of the uptake of calcein and cytotoxicity of doxorubicin in human cervical cancer HeLa-IU(1) cells and human colon cancer Caco-2 cells demonstrated that folate-tethered liposomes were efficient in selective delivery to cancer cells overexpressing folate receptors [14].

Biological context of calcein

• We have monitored kinetics of fusion between cell pairs consisting of a single influenza hemaglutinin (HA)-expressing cell and a single erythrocyte (RBC) that had been labeled with both a fluorescent lipid (Dil) in the membrane and a fluorescent solute (calcein) in the aqueous space [15].
• Serum deprivation potentiated apoptosis caused by K+ withdrawal, reducing cell viability by approximately one half of control values after 12 hr as measured by calcein fluorescence [16].
• Using the calcein AM method, at day 2, 10 nmol/l rapamycin caused a reduction in cell viability to 73 +/- 5% of control (P < 0.001) [17].
• Since pore opening must be accompanied by depolarization, we conclude that short PTP openings are detected only by trapped calcein and may have little impact on cell viability, while changes of TMRM distribution require longer PTP openings, which cause release of cytochrome c and may result in cell death [18].
• As these enzymes release their iron ions under oxidative-stress conditions, the intracellular labile iron pool, monitored with calcein, was higher in cells with reduced Hsp60 levels [19].

Anatomical context of calcein

• Thirteen cell lines with different levels of Pgp and MRP expression were used to assess the ability of calcein acetoxymethyl ester (calcein-AM) uptake and calcein efflux to measure Pgp and MRP functions, respectively [20].
• After 2-3 h, the anionic fluorophore calcein abruptly began to enter the cytosol, and nuclei labeled with cationic propidium after another 2-5 min [4].
• Reversible depolarization of the mitochondrial membrane potential () and decrease in fluorescence of a mitochondria-entrapped dye, calcein, are observed coincidentally [21].
• The fluorescence of hepatocytes loaded with the fluorescent metal indicators, phen green SK (PG SK), phen green FL (PG FL), calcein, or fluorescein desferrioxamine (FL-DFO), was quenched when iron was added to the cells in a membrane-permeable form [22].
• We report here, that unlike other antimicrobial proteins, Hsts do not display lytic activities to lipid membranes, measured by release and dequenching of the fluorescent dye calcein [23].

Associations of calcein with other chemical compounds

• There was a good correlation between MRP expression and the modulatory effect of probenecid (a specific modulator of MRP) on the calcein efflux (r = .91, P = .0003) and between Pgp expression and the modulatory effect of CsA on calcein-AM uptake (r = .96, P < .0001) [20].
• Radiation-induced ROS/RNS, depolarization, and calcein fluorescence decrease are inhibited by the mitochondrial permeability transition inhibitor, cyclosporin A, but not the structural analogue, cyclosporin H [21].
• Glycine slowed, but did not prevent calcein entry, whereas permeation of propidium and high molecular weight dextrans was blocked completely by glycine [4].
• At a concentration of 125 nM, Bax caused the release of the intermembranous proteins cytochrome c and adenylate kinase and the release from the matrix of sequestered calcein, effects prevented by the inhibitor of the PTP cyclosporin A (CSA) [24].
• Treatment with arachidonic acid or induces PTP opening in situ with similar kinetics, as assessed by the calcein loading-Co(2+) quenching technique (Petronilli, V., Miotto, G., Canton, M., Colonna, R., Bernardi, P., and Di Lisa, F. (1999) Biophys. J. 76, 725-734) [18].

Gene context of calcein

• In contrast, these inhibitors failed to alter the calcein fluorescence in CEM-7A cells, which markedly lost MRP1 expression [25].
• To obtain more insight in the handling of drugs by both proteins, we performed a detailed kinetic analysis of the efflux of calcein-acetoxymethyl ester (CAL-AM), a common neutral substrate for both proteins and compared it with the kinetics of efflux of calcein (CAL) which is only effluxed by MRP [26].
• The differential pharmacological sensitivity of apical (MRP2) and basolateral calcein efflux provides tools for dissecting MRP isoform functional roles [27].
• They also inhibited transport in membrane vesicles prepared from tumour cells expressing MRP1 or MRP4 and blocked calcein efflux from MRP1-overexpressing cells and BCECF efflux from MRP4-overexpressing cells [28].
• High extracellular calcium did not influence the P-gp mediated extrusion of calcein/AM as P-gp substrate [29].

Analytical, diagnostic and therapeutic context of calcein

• Using fluorescence-recovery after photobleaching, we observed that DsRed1 and calcein were highly mobile within the matrix of individual mitochondria, and that mitochondria within a cell were not lumenally continuous [30].
• When 2 x 10(4) vital dye-labeled CRC cells were added to murine SEC monolayers, more than 30% of clone A cells lost calcein AM fluorescence compared to fewer than 5% of CX-1 cells after 24 h of coculture with SECs [31].
• This modification significantly decreases the pH-dependent release of a charged water-soluble fluorophore, calcein, from liposomes suspended in buffer or cell culture medium [32].
• Interaction of artificial lipid bilayers (liposomes) with the purified transit peptide (SS-tp) of the precursor form of the small subunit for ribulose-2,5-bisphosphate carboxylase/oxygenase (prSSU) has been studied using a vesicle-disruption assay (calcein dye release) and electron microscopy [33].
• Repeated daily subcutaneous injections of AC-100 onto the calvariae in mice increased bone thickness and stimulated new bone formation as determined by the calcein double-labeling technique [34].

References