Vacuolar-type H(+)-ATPases are functionally expressed in plasma membranes of human tumor cells

1993 ◽  
Vol 265 (4) ◽  
pp. C1015-C1029 ◽  
Author(s):  
R. Martinez-Zaguilan ◽  
R. M. Lynch ◽  
G. M. Martinez ◽  
R. J. Gillies
Keyword(s):  
Plasma Membrane ◽  
Tumor Cells ◽  
Cell Lines ◽  
Mammalian Cells ◽  
Plasma Membranes ◽  
Human Tumor ◽  
Atp Depletion ◽  
Second Phase ◽  
Bafilomycin A1 ◽  
P Type

Mammalian cells generally regulate their intracellular pH (pHi) via collaboration between Na(+)-H+ exchanger and HCO3- transport. In addition, a number of normal mammalian cells have been identified that express H(+)-adenosinetriphosphatases (ATPases) in their plasma membranes. Because tumor cells often maintain a high pHi, we hypothesized that they might functionally express H(+)-ATPases in their plasma membranes. In the first phase of the present study, we screened 19 normal and tumorigenic human cell lines for the presence of plasmalemmal H(+)-ATPase activity using bafilomycin A1 to inhibit V-type H(+)-ATPase and Sch-28080 to inhibit P-type H(+)-K(+)-ATPase. Bafilomycin A1 decreased pHi in the six tumor cell lines with the highest resting pHi in the absence of HCO3-. Sch-28080 did not affect pHi in any of the human cells. Simultaneous measurement of pH in the cytoplasm and in the endosomes/lysosomes localized the activity of bafilomycin to the plasma membrane in three cell lines. In the second phase of this study, these three cell lines were shown to recover from NH4(+)-induced acid loads in the absence of Na+. This recovery was inhibited by N-ethylmaleimide, bafilomycin A1, and ATP depletion and was not significantly affected by vanadate, Sch-28080, or hexamethyl amiloride. These results indicate that a vacuolar type H(+)-ATPase is expressed in the plasma membrane of some tumor cells.

Interaction of Human Tumor Cells with Human Platelets and the Coagulation System

1983 ◽  
Vol 50 (03) ◽  
pp. 726-730 ◽  
Author(s):  
Hamid Al-Mondhiry ◽  
Virginia McGarvey ◽  
Kim Leitzel
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Cell Lines ◽  
Human Tumor ◽  
Human Platelets ◽  
Factor Vii ◽  
Coagulation System ◽  
Breast Adenocarcinoma ◽  
Activate Factor ◽  
Tumor Cell Lines

SummaryThis paper reports studies on the interaction between human platelets, the plasma coagulation system, and two human tumor cell lines grown in tissue culture: Melanoma and breast adenocarcinoma. The interaction was monitored through the use of 125I- labelled fibrinogen, which measures both thrombin activity generated by cell-plasma interaction and fibrin/fibrinogen binding to platelets and tumor cells. Each tumor cell line activates both the platelets and the coagulation system simultaneously resulting in the generation of thrombin or thrombin-like activity. The melanoma cells activate the coagulation system through “the extrinsic pathway” with a tissue factor-like effect on factor VII, but the breast tumor seems to activate factor X directly. Both tumor cell lines activate platelets to “make available” a platelet- derived procoagulant material necessary for the conversion of prothrombin to thrombin. The tumor-derived procoagulant activity and the platelet aggregating potential of cells do not seem to be inter-related, and they are not specific to malignant cells.

A truncated intracellular HER2/neu receptor produced by alternative RNA processing affects growth of human carcinoma cells

1993 ◽  
Vol 13 (4) ◽  
pp. 2247-2257
Author(s):  
G K Scott ◽  
R Robles ◽  
J W Park ◽  
P A Montgomery ◽  
J Daniel ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Cells ◽  
Cell Lines ◽  
Rna Processing ◽  
Human Tumor ◽  
Full Length ◽  
Splice Donor Site ◽  
Breast Cancer Cell Lines ◽  
Her2 Receptor ◽  
Human Carcinoma

Cloned sequences encoding a truncated form of the HER2 receptor were obtained from cDNA libraries derived from two HER2-overexpressing human breast cancer cell lines, BT-474 and SK-BR-3. The 5' 2.1 kb of the encoded transcript is identical to that of full-length 4.6-kb HER2 transcript and would be expected to produce a secreted form of HER2 receptor containing only the extracellular ligand binding domain (ECD). The 3' end of the truncated transcript diverges 61 nucleotides before the receptor's transmembrane region, reads through a consensus splice donor site containing an in-frame stop codon, and contains a poly(A) addition site, suggesting that the truncated transcript arises by alternative RNA processing. S1 nuclease protection assays show a 40-fold variation in the abundance of the truncated 2.3-kb transcript relative to full-length 4.6-kb transcript in a panel of eight HER2-expressing tumor cell lines of gastric, ovarian, and breast cancer origin. Expression of this truncated transcript in COS-1 cells produces both secreted and intracellular forms of HER2 ECD; however, immunofluorescent labeling of HER2 ECD protein in MKN7 tumor cells that natively overexpress the 2.3-kb transcript suggests that transcriptionally generated HER2 ECD is concentrated within the perinuclear cytoplasm. Metabolic labeling and endoglycosidase studies suggest that this HER2 ECD (100 kDa) undergoes differential trafficking between the endoplasmic reticulum and Golgi compartments compared with full-length (185-kDa) HER2 receptor. Transfection studies indicate that excess production of HER2 ECD in human tumor cells overexpressing full-length HER2 receptor can result in resistance to the growth-inhibiting effects of anti-HER2 monoclonal antibodies such as muMAb4D5. These findings demonstrate alternative processing of the HER2 transcript and implicate a potentially important growth regulatory role for intracellularly sequestered HER2 ECD in HER2-amplified human tumors.

Transbilayer movement of fluorescent and spin-labeled phospholipids in the plasma membrane of human fibroblasts: a quantitative approach

1996 ◽  
Vol 109 (3) ◽  
pp. 687-698 ◽  
Author(s):  
T. Pomorski ◽  
P. Muller ◽  
B. Zimmermann ◽  
K. Burger ◽  
P.F. Devaux ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Initial Velocity ◽  
Plasma Membranes ◽  
Atp Hydrolysis ◽  
Human Fibroblasts ◽  
Atp Depletion ◽  
Aminophospholipid Translocase ◽  
Order Of Magnitude ◽  
Complicating Factors ◽  
First Time

All phospholipids in the plasma membrane of eukaryotic cells are subject to a slow passive transbilayer movement. In addition, aminophospholipids are recognized by the so-called aminophospholipid translocase, and are rapidly moved from the exoplasmic to the cytoplasmic leaflet of the plasma membrane at the expense of ATP hydrolysis. Though these principal pathways of transbilayer movement of phospholipids probably apply to all eukaryotic plasma membranes, studies of the actual kinetics of phospholipid redistribution have been largely confined to non-nucleated cells (erythrocytes). Experiments on nucleated cells are complicated by endocytosis and metabolism of the lipid probes inserted into the plasma membrane. Taking these complicating factors into account, we performed a detailed kinetic study of the transbilayer movement of short-chain fluorescent (N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl); NBD) and, for the first time, spin-labeled analogues of phosphatidylcholine (PC), -ethanolamine (PE), -serine (PS), and sphingomyelin (SM) in the plasma membrane of cultured human gingival fibroblasts. At 20 degrees C, the passive transbilayer diffusion of NBD analogues was very slow, and the choline-containing NBD analogues were internalized predominantly by endocytosis. Spin-labeled analogues of PC and SM showed higher passive transbilayer diffusion rates, and probably entered the cell by both passive transbilayer movement and endocytosis. In contrast, the rapid uptake of NBD- and spin-labeled aminophospholipid analogues could be mainly ascribed to the action of the aminophospholipid translocase, since it was inhibited by ATP depletion and N-ethylmaleimide pretreatment. The initial velocity of NBD-aminophospholipid translocation was eight to ten times slower than that of the corresponding spin-labeled lipid, and the half-times of redistribution of NBD-PS and spin-labeled PS were 7.2 and 3.6 minutes, respectively. Our data indicate that in human fibroblasts the initial velocity of aminophospholipid translocation is at least one order of magnitude higher than that in human erythrocytes, which should be sufficient to maintain the phospholipid asymmetry in the plasma membrane.

Characterization of two Mg2+transporters in sealed plasma membrane vesicles from rat liver

1998 ◽  
Vol 275 (4) ◽  
pp. C995-C1008 ◽  
Author(s):  
Christie Cefaratti ◽  
Andrea Romani ◽  
Antonio Scarpa
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Intracellular Signaling ◽  
Mammalian Cells ◽  
Plasma Membranes ◽  
Membrane Vesicles ◽  
Channel Blockers ◽  
Transport Mechanisms ◽  
Plasma Membrane Vesicles ◽  
New Information

The plasma membrane of mammalian cells possesses rapid Mg2+ transport mechanisms. The identity of Mg2+ transporters is unknown, and so are their properties. In this study, Mg2+ transporters were characterized using a biochemically and morphologically standardized preparation of sealed rat liver plasma membranes (LPM) whose intravesicular content could be set and controlled. The system has the advantages that it is not regulated by intracellular signaling machinery and that the intravesicular ion milieu can be designed. The results indicate that 1) LPM retain trapped intravesicular total Mg2+with negligible leak; 2) the addition of Na+ or Ca2+ induces a concentration- and temperature-dependent efflux corresponding to 30–50% of the intravesicular Mg2+; 3) the rate of flux is very rapid (137.6 and 86.8 nmol total Mg2+ ⋅ μm−2 ⋅ min−1after Na+ and Ca2+ addition, respectively); 4) coaddition of maximal concentrations of Na+ and Ca2+ induces an additive Mg2+ efflux; 5) both Na+- and Ca2+-stimulated Mg2+ effluxes are inhibited by amiloride, imipramine, or quinidine but not by vanadate or Ca2+ channel blockers; 6) extracellular Na+ or Ca2+ can stimulate Mg2+ efflux in the absence of Mg2+ gradients; and 7) Mg2+ uptake occurs in LPM loaded with Na+ but not with Ca2+, thus indicating that Na+/Mg2+but not Ca2+/Mg2+exchange is reversible. These data are consistent with the operation of two distinct Mg2+ transport mechanisms and provide new information on rates of Mg2+ transport, specificity of the cotransported ions, and reversibility of the transport.

Interaction Of Platelets And Tumor Cells: Differentiation Between Nine Human Tumor Cell Lines Based On Aggregation And Effects Of Apyrase, Hirudin And Phospholipase D

1981 ◽  
Author(s):  
G A Jamieson ◽  
Eva Bastida ◽  
Antonio Ordinas
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Cell Lines ◽  
Phospholipase D ◽  
Lung Carcinoma ◽  
Platelet Rich Plasma ◽  
Human Tumor ◽  
Clotting System ◽  
Cell Lung Carcinoma ◽  
Aggregation Pattern

Aggregation mechanisms have been examined in a homologous system using heparinized human platelet-rich plasma with cell lines derived from human tumors. The A549 (epithelial lung carcinoma) and Hut23 (adenocarcinoma) did not aggregate platelets at 107 cells/ml. Other cell lines could not be classified by aggregation pattern alone since all gave biphasic or quasibiphasic patterns. HT 29 (adenocarcinoma) , SKBR3 (adenocarcinoma), HT 144 (melanoma) and Hut 20 (large cell lung carcinoma) were inhibited by apyrase and phospholipase D but not by hirudin: aggregation induced by this group is probably primarily dependent on ADP. Aggregation by SKNMC (mesothelioma) and Hut 28 (mesothelioma) was inhibited by hirudin and phospholipase D but not by apyrase. Aggregation by this second group probably involves activation of the clotting system in the early stages but can be differentiated from a similar mechanism with U87MG since thq latter is not inhibited by phospholipase D. Phospholipase C had no effect on any cell line and phospholipase A2 inhibited all cell lines, as did its hydrolytic product, lysolecthin. Platelet aggregating material (PAM) could not be isolated by urea extraction of any of these human tumor cells. These results suggest that various inhibitors are necessary to allow classification of mechanisms of tumor cell-induced platelet aggregation.

scholarly journals Characterization of the plasma-membrane calcium pump from Trypanosoma cruzi

1995 ◽  
Vol 306 (1) ◽  
pp. 299-303 ◽  
Author(s):  
G Benaim ◽  
S N J Moreno ◽  
G Hutchinson ◽  
V Cervino ◽  
T Hermoso ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Trypanosoma Cruzi ◽  
Mammalian Cells ◽  
Membrane Vesicles ◽  
High Sensitivity ◽  
Bovine Brain ◽  
Calcium Pump ◽  
Plasma Membrane Vesicles ◽  
P Type

Despite previous reports [McLaughlin (1985) Mol. Biochem. Parasitol. 15, 189-201; Ghosh, Ray, Sarkar and Bhaduri (1990) J. Biol. Chem. 265, 11345-11351; Mazumder, Mukherjee, Ghosh, Ray and Bhaduri (1992) J. Biol. Chem. 267, 18440-18446] suggesting that the plasma-membrane Ca(2+)-ATPases of different trypanosomatids differ from the Ca2+ pumps present in mammalian cells, Trypanosoma cruzi plasma-membrane Ca(2+)-ATPase shares several characteristics with the Ca2+ pumps present in other systems. This enzyme could be partially purified from epimastigote plasma-membrane vesicles using calmodulin-agarose affinity chromatography. The activity of the partially purified enzyme was stimulated by T. cruzi or bovine brain calmodulin. In addition, the enzyme cross-reacted with antiserum and monoclonal antibody 5F10 raised against human red-blood-cell Ca(2+)-ATPase, has a molecular mass of 140 kDa and forms Ca(2+)-dependent hydroxylamine-sensitive phosphorylated intermediates. These results, together with its high sensitivity to vanadate, indicate that this enzyme belongs to the P-type class of ionic pumps.

scholarly journals Sphingolipid Domains in the Plasma Membranes of Fibroblasts Are Not Enriched with Cholesterol

2013 ◽  
Vol 288 (23) ◽  
pp. 16855-16861 ◽  
Author(s):  
Jessica F. Frisz ◽  
Haley A. Klitzing ◽  
Kaiyan Lou ◽  
Ian D. Hutcheon ◽  
Peter K. Weber ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Plasma Membrane ◽  
High Resolution ◽  
Mammalian Cells ◽  
Plasma Membranes ◽  
Secondary Ion Mass Spectrometry ◽  
Cholesterol Depletion ◽  
Fibroblast Cells ◽  
Secondary Ion ◽  
Rule Out

The plasma membranes of mammalian cells are widely expected to contain domains that are enriched with cholesterol and sphingolipids. In this work, we have used high-resolution secondary ion mass spectrometry to directly map the distributions of isotope-labeled cholesterol and sphingolipids in the plasma membranes of intact fibroblast cells. Although acute cholesterol depletion reduced sphingolipid domain abundance, cholesterol was evenly distributed throughout the plasma membrane and was not enriched within the sphingolipid domains. Thus, we rule out favorable cholesterol-sphingolipid interactions as dictating plasma membrane organization in fibroblast cells. Because the sphingolipid domains are disrupted by drugs that depolymerize the cells actin cytoskeleton, cholesterol must instead affect the sphingolipid organization via an indirect mechanism that involves the cytoskeleton.

High hydrostatic pressure to induce immunogenic cell death in human tumor cells.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 3076-3076
Author(s):  
Iva Truxova ◽  
Jitka Fucikova ◽  
Irena Moserova ◽  
Simona Partlova ◽  
Jirina Bartunkova ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Hydrostatic Pressure ◽  
Tumor Cells ◽  
Cell Lines ◽  
Primary Tumor ◽  
High Hydrostatic Pressure ◽  
Human Tumor ◽  
Immunogenic Cell Death ◽  
Human Tumor Cells

3076 Background: Recent studies have identified molecular events characteristic of immunogenic cell death. These include surface exposure of calreticulin, HSP70 and HSP90, release of intranuclear HMGB1 and secretion of ATP from dying cells. Several chemotherapeutic agents, including anthracyclins, oxaliplatin and bortezomib, and hypericin-based photodynamic therapy have been described to induce the immunogenic cell death in human tumor cells. We investigated the potential of high hydrostatic pressure (HHP) to induce immunogenic cell death in human tumor cells. Methods: Prostate and ovarian cancer cell lines and primary tumor cells were treated by HHP and we analyzed the kinetics of the expression of immunogenic cell death markers. HHP killed tumor cells expressing immunogenic cell death markers were tested for their ability to activate dendritic cells (DCs), to induce tumor specific T cells and regulatory T cells. Results: HHP induced rapid expression of HSP70, HSP90 and calreticulin on the cell surface of all tested cell lines and primary tumor cells. HHP also induced release of HMGB1 and ATP from treated cells. The kinetics of expression was similar to doxorubicin, HHP, however, induced 1.5-2 fold higher expression of HSP70, HSP90 and calreticulin. The interaction of DCs with HHP-treated tumor cells led to the faster rate of phagocytosis, significant upregulation of CD83, CD86 and HLA-DR and release of IL-6, IL-12p70 and TNFα. The ability of HHP-killed tumor cells to promote DCs maturation was cell contact dependent. DCs pulsed with tumor cells killed by HHP induced high numbers of tumor-specific CD4+ and CD8+IFN-g-producing T cells even in the absence of additional maturation stimulus. DCs pulsed with HHP treated tumor cells also induced the lowest number of regulatory T cells among the tested conditions. Cells treated by HHP can by cryopreserved in liquid nitrogen and retain their immunogenic properties upon thawing thus allowing for their convenient use in the manufacturing of cancer immunotherapy products. Conclusions: High hydrostatic pressure is a reliable and very potent inducer of immunogenic cell death in the wide range of human tumor cell lines and primary tumor cells.

scholarly journals A Nonclonogenic Cytotoxicity Assay Using Primary Cultures of Patient Tumor Cells for Anticancer Drug Screening

1998 ◽  
Vol 3 (3) ◽  
pp. 207-216 ◽  
Author(s):  
Sumeer Dhar ◽  
Joachim Gullbo ◽  
Kenneth Nilsson ◽  
Peter Nygren ◽  
Rolf Larsson
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Cell Lines ◽  
Anticancer Drug ◽  
Drug Screening ◽  
Primary Cultures ◽  
Human Tumor ◽  
Lymphocytic Leukemia ◽  
Cell Systems ◽  
Sensitivity Pattern

Primary cultures of cells from patients with chronic lymphocytic leukemia (CLL) and ovarian carcinoma (Ovca) were compared with the renal carcinoma ACHN and the lymphocytic CCRF-CEM human tumor cell lines in response to 63 toxic or nontoxic compounds. The experiments were conducted at 1, 10, and 100 μ/ml in 96-well microtiter plates for an assay time of 72 h. The plates were analyzed by the fully automated Dynatech Immuno Assay System (DIAS) using Alamar blue as a fluorometric/colorimetric indicator of metabolic activity. Drug response data were reported as the area under the tumor cell survival-concentration curve (AUC). Noncytotoxic compounds were classified as inactive by all cell systems. According to the AUC, CCRF-CEM and CLL cells were the most sensitive, followed by ACHN, and then Ovca. Many of the clinically active drugs were detected by all cell systems. However, the sensitivity pattern differed considerably between the cell types as judged from correlation analysis, and a higher proportion of clinically inactive drugs were scored as active by the cell lines compared with the primary cultures. Ovca showed the highest ratio of clinically solid tumor active/clinically inactive agents followed by CLL. The results indicate that primary cultures of human tumor cells may be a useful and valuable model for anticancer drug screening.

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