CCK-B receptors produce similar signals but have opposite growth effects in CHO and Swiss 3T3 cells

1997 ◽  
Vol 273 (5) ◽  
pp. C1449-C1457 ◽  
Author(s):  
Katharina Detjen ◽  
David Yule ◽  
Min-Jen Tseng ◽  
John A. Williams ◽  
Craig D. Logsdon
Keyword(s):  
B Cells ◽  
Dna Synthesis ◽  
Cell Types ◽  
Receptor Activation ◽  
Receptor Expression ◽  
Growth Responses ◽  
3T3 Cells ◽  
Growth Effects ◽  
Receptor Coupling ◽  
Swiss 3T3

Rat cholecystokinin-B (CCK-B) receptors were transfected into Chinese hamster ovary (CHO)-K1 (CHO-CCK-B) and Swiss 3T3 (Swiss 3T3-CCK-B) cells, and the effects of receptor activation on cell proliferation and intracellular signaling were investigated. CCK octapeptide (CCK-8) treatment had no effect on cell growth in quiescent CHO-CCK-B cells but inhibited DNA synthesis, proliferation, and colony formation when the cells were grown in fetal bovine serum (FBS). In contrast, CCK-8 stimulated DNA synthesis in quiescent Swiss 3T3-CCK-B cells and had no effect when the cells were grown in FBS. These differences in growth responses were not due to differences in the level of receptor expression, as similar numbers of receptors were present in both cell types. To determine whether the different growth effects were due to differences in receptor coupling to common second messenger pathways, we investigated the effects of CCK-8 on several known intracellular signals. In both cell types, CCK-8 stimulated increases in intracellular Ca2+concentration and polyphosphoinositide hydrolysis with similar potencies and efficacies. CCK-8 also stimulated arachidonate release from both cell types, although the potency was higher in the CHO cells. Adenosine 3′,5′-cyclic monophosphate generation was observed at high agonist concentrations in both cell types and was much greater in cells with higher receptor density. In summary, receptor activation had opposite effects on growth parameters in CHO and Swiss 3T3 cells, but only minor differences were observed in the characteristics of CCK-B receptor coupling to specific second messengers in the two cell types. Thus cellular context is a principal determinant of the biological effects of CCK-B receptor activation, and differences in biological responses may occur independently of major differences in receptor coupling.

Signalling Pathways Involved in the Mitogenic Effects of cAMP

1997 ◽  
Vol 92 (5) ◽  
pp. 445-451 ◽  
Author(s):  
D. J. Withers
Keyword(s):  
Dna Synthesis ◽  
Mapk Pathway ◽  
Critical Role ◽  
Cell Types ◽  
Mapk Cascade ◽  
Mitogen Activated Protein Kinase ◽  
Signalling Pathways ◽  
3T3 Cells ◽  
Mitogen Activated Protein ◽  
Swiss 3T3

1. Elevation of intracellular cyclic AMP (cAMP) is a potent mitogenic signal for a number of cell types, including Swiss 3T3 cells, thyroid epithelial cells and the somatotroph cells of the anterior pituitary. 2. Activation of the mitogen-activated protein kinase (MAPK) cascade has been shown to underlie the mitogenic effects of many growth factors. However, the precise relationship between the mitogenic effects of cAMP and the MAPK cascade is not fully defined. 3. In Swiss 3T3 cells, elevation of cAMP did not stimulate kinases at all three levels of the MAPK cascade. Additionally, blockade of the MAPK pathway failed to inhibit cAMP-stimulated DNA synthesis. 4. Mitogenic combinations of cAMP strongly stimulated the phosphorylation and activation of the serine/threonine kinase p70 S6 kinase, p70S6K, an effect that was inhibited by rapamycin. This agent markedly inhibited cAMP-stimulated DNA synthesis, suggesting a critical role for p70S6K in cAMP mitogenic signalling. 5. Thus, multiple parallel but distinct signalling pathways may be involved in the action of mitogens. This redundancy has important implications for the pathogenesis and treatment of conditions characterized by inappropriate activation of growth factor signalling pathways.

scholarly journals Sorting out of normal and virus-transformed cells in cellular aggregates.

1976 ◽  
Vol 68 (2) ◽  
pp. 276-286 ◽  
Author(s):  
H Gershman ◽  
J Drumm ◽  
L Culp
Keyword(s):  
B Cells ◽  
Cultured Cells ◽  
Cell Types ◽  
Transformed Cells ◽  
3T3 Cells ◽  
Con A ◽  
Adhesive Properties ◽  
Established Cell ◽  
Swiss 3T3 ◽  
Cellular Aggregates

The sorting-out behavior (self-segregation of two cell types from mixtures of the two) of five different established cell lines was studied. Eight of the ten possible binary combinations of these lines, cultured as cellular aggregates, were examined. Mouse BALB/c 3T3 cells sorted out internally to the corresponding malignant SV40 virus-transformed 3T3 cells. The transformed 3T3 line (SVT-2) did not sort out from a revertant line selected from SVT-2 cells by resistance to concanavalin A (con A). The revertant cells sorted out externally to the parent BALB/c 3T3 cells, although segregation was generally incomplete. BALB/c 3T3 cells did not sort out from another contact-inhibited line of 3T3 cells derived from Swiss albino mice (Swiss 3T3). Both BALB/c 3T3 and Swiss 3T3 cells sorted out from cells of the contact-inhibited hamster line, NIL B. Instead of a two-layered sphere, however, a three-layered structure was observed with most of the NIL B cells external to the 3T3 cells, and a few NIL B cells comprising the center of the sphere. On the other hand, NIL B cells did not consistently sort out from either the SVT-2 or con A cells. In general, sorting out between pairs of these five lines are slower and less complete than is generally observed between the more extensively studied chick embryonic tissue cells, suggesting that the cultured cells may be more closely related in their adhesive properties. The internal segregation of BALB/c 3T3 cells relative to SVT-2 cells is consistent with the hypothesis that transformed cells are less adhesive than their nontransformed counterparts.

scholarly journals Pregnancy-enhanced Ca2+ responses to ATP in uterine artery endothelial cells is due to greater capacitative Ca2+ entry rather than altered receptor coupling

2006 ◽  
Vol 190 (2) ◽  
pp. 373-384 ◽  
Author(s):  
Shannon M Gifford ◽  
Fu-Xian Yi ◽  
Ian M Bird
Keyword(s):  
Endothelial Cells ◽  
Uterine Artery ◽  
Purinergic Receptor ◽  
Cell Types ◽  
P2y Receptors ◽  
Receptor Expression ◽  
Receptor Subtype ◽  
Initial Transient ◽  
Receptor Coupling ◽  
Specific Variation

Uterine artery endothelial cells (UAEC) derived from pregnant (P-UAEC) and nonpregnant (NP-UAEC) ewes retain pregnancy-specific differences in cell signaling as well as vasodilator production through passage 4. In particular, when P- and NP-UAEC are stimulated with ATP over a 2.5 min recording period, they exhibit similar initial transient peaks in the intracellular free Ca2+ concentration ([Ca2+]i), but the P-UAEC show a heightened sustained phase. In order to establish whether thiswas due to an altered subclass of purinergic receptor (P2), both the dose dependencyof [Ca2+]i responses to ADP and UTP and the profile of purinergic receptor expression are determined in NP- and P-UAEC. Our findings indicate that while several isoforms of P2X and P2Y receptors are present, it is P2Y2 that is responsible for the ATP-induced initial transient peak in both cell types. We also characterized several key components of the ATP-induced Ca2+ signaling cascade, including the inositol 1,4,5-trisphosphate receptor and G-proteins, but could not confirm any pregnancy-specific variation in the protein expression that correlated with pregnancy-specific differences in prolonged Ca2+ signaling. We thus investigated whether such a difference may be inherent to the cell itself rather than specific to the purinergic receptor-signaling pathway. Using thapsigargin (Tg), we were able to demonstrate that the initial Tg-sensitive intracellular pool of Ca2+is nearly identical with the capacity in both cell types, but the P-UAEC is nonetheless capable of greater capacitative Ca2+ entry (CCE) than NP-UAEC. Furthermore, CCE induced by Tg could be dramatically inhibited by 2-aminoethoxydiphenyl borate, suggesting a role for store-operated channels in the ATP-induced [Ca2+]i response. We conclude that changes at the level of capacitative entry mechanisms rather than switching of receptor subtype or coupling to phospholipase C underlies pregnancy adaptation of UAEC at the level of Ca2+signaling.

Microinjection of smg/rap1/Krev-1 p21 into Swiss 3T3 cells induces DNA synthesis and morphological changes

1992 ◽  
Vol 12 (8) ◽  
pp. 3407-3414
Author(s):  
Y Yoshida ◽  
M Kawata ◽  
Y Miura ◽  
T Musha ◽  
T Sasaki ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Laser Scanning ◽  
Morphological Changes ◽  
Stress Fibers ◽  
Confocal Laser ◽  
3T3 Cells ◽  
Membrane Ruffling ◽  
Ras P21 ◽  
Swiss 3T3 ◽  
Gamma S

Microinjection of either Ki-rasVal-12 p21 or the GDP-bound form of Ki-ras p21 plus smg GDP dissociation stimulator (GDS), a stimulatory GDP/GTP exchange protein for Ki-ras p21, smg/rap1/Krev-1 p21, and rho p21, into quiescent Swiss 3T3 cells induced DNA synthesis irrespective of the presence or absence of insulin. The guanosine 5'-(3-O-thio)triphosphate (GTP gamma S)-bound form of smg p21B or the GDP-bound form of smg p21B plus smg GDS also induced DNA synthesis but only in the presence of insulin. Either the GDP-bound form of Ki-ras p21 or the same form of smg p21B alone was inactive, but smg GDS alone was slightly active only in the presence of insulin. The morphology of the cells was analyzed by scanning electron, phase-contrast, and confocal laser scanning microscopies. Ki-rasVal-12 p21 induced membrane ruffling irrespective of the presence or absence of insulin. The GTP gamma S-bound form of smg p21B showed the same effect only in the presence of insulin. Either the GDP-bound form of Ki-ras p21, the same form of smg p21B, or smg GDS alone was inactive. Upon microinjection of Ki-rasVal-12 p21, stress fibers markedly decreased and the cells became round and piled up. In contrast, upon microinjection of the GTP gamma S-bound form of smg p21B, stress fibers did not markedly decrease and the cells neither became round nor piled up. These results indicate that both ras p21 and smg p21 are mitogenic in Swiss 3T3 cells but that their actions are slightly different.

scholarly journals Th2 Cytokine Modulates Herpesvirus Reactivation in a Cell Type Specific Manner

2021 ◽  
Author(s):  
Guoxun Wang ◽  
Christina Zarek ◽  
Tyron Chang ◽  
Lili Tao ◽  
Alexandria Lowe ◽  
...  
Keyword(s):  
B Cells ◽  
Cell Types ◽  
The Body ◽  
Receptor Expression ◽  
Conditional Knockout ◽  
Interleukin 4 ◽  
Virus Reactivation ◽  
Cell Type ◽  
Murine Gammaherpesvirus ◽  
Cell Type Specific

Gammaherpesviruses, such as Epstein-Barr virus (EBV), Kaposi’s sarcoma associated virus (KSHV), and murine γ-herpesvirus 68 (MHV68), establish latent infection in B cells, macrophages, and non-lymphoid cells, and can induce both lymphoid and non-lymphoid cancers. Research on these viruses has relied heavily on immortalized B cell and endothelial cell lines. Therefore, we know very little about the cell type specific regulation of virus infection. We have previously shown that treatment of MHV68-infected macrophages with the cytokine interleukin-4 (IL-4) or challenge of MHV68-infected mice with an IL-4-inducing parasite leads to virus reactivation. However, we do not know if all latent reservoirs of the virus, including B cells, reactivate the virus in response to IL-4. Here we used an in vivo approach to address the question of whether all latently infected cell types reactivate MHV68 in response to a particular stimulus. We found that IL-4 receptor expression on macrophages was required for IL-4 to induce virus reactivation, but that it was dispensable on B cells. We further demonstrated that the transcription factor, STAT6, which is downstream of the IL-4 receptor and binds virus gene 50 N4/N5 promoter in macrophages, did not bind to the virus gene 50 N4/N5 promoter in B cells. These data suggest that stimuli that promote herpesvirus reactivation may only affect latent virus in particular cell types, but not in others. Importance Herpesviruses establish life-long quiescent infections in specific cells in the body, and only reactivate to produce infectious virus when precise signals induce them to do so. The signals that induce herpesvirus reactivation are often studied only in one particular cell type infected with the virus. However, herpesviruses establish latency in multiple cell types in their hosts. Using murine gammaherpesvirus-68 (MHV68) and conditional knockout mice, we examined the cell type specificity of a particular reactivation signal, interleukin-4 (IL-4). We found that IL-4 only induced herpesvirus reactivation from macrophages, but not from B cells. This work indicates that regulation of virus latency and reactivation is cell type specific. This has important implications for therapies aimed at either promoting or inhibiting reactivation for the control or elimination of chronic viral infections.

Differential activation of focal adhesion kinase, Rho and Rac by the ninth and tenth FIII domains of fibronectin

1999 ◽  
Vol 112 (17) ◽  
pp. 2937-2946
Author(s):  
N.A. Hotchin ◽  
A.G. Kidd ◽  
H. Altroff ◽  
H.J. Mardon
Keyword(s):  
Growth Factor ◽  
Focal Adhesion Kinase ◽  
Signaling Pathways ◽  
Focal Adhesion ◽  
Cell Attachment ◽  
Cell Types ◽  
Integrin Receptors ◽  
3T3 Cells ◽  
Swiss 3T3 ◽  
Kinase Phosphorylation

Fibronectins are widely expressed extracellular matrix ligands that are essential for many biological processes. Fibronectin-induced signaling pathways are elicited in diverse cell types when specific integrin receptors bind to the ninth and tenth FIII domains, FIII9-10. Integrin-mediated signal transduction involves activation of signaling pathways of the growth factor-dependent Ras-related small GTP-binding proteins Rho and Rac, and phosphorylation of focal adhesion kinase. We have dissected the requirement of FIII9 and FIII10 for Rho and Rac activity and phosphorylation of focal adhesion kinase in BHK fibroblasts and Swiss 3T3 cells. We demonstrate that FIII10 supports cell attachment but does not induce phosphorylation of focal adhesion kinase. In Swiss 3T3 cells, growth factor-independent phosphorylation of focal adhesion kinase and downstream adhesion events are dependent upon the presence of FIII9 in the intact FIII9-10 pair, whereas FIII10-mediated focal adhesion kinase phosphorylation requires a synergistic signal from growth factors. Furthermore, FIII10 is able to elicit cellular responses mediated by Rho, but not Rac, whereas FIII9-10 can elicit both Rho- and Rac-mediated responses. We propose that activation of specific integrin subunits by the FIII10 and FIII9-10 ligands elicits distinct signaling events. This may represent a general molecular mechanism for activation of receptor-specific signaling pathways by a multi-domain ligand.

Interferon inhibition of DNA synthesis in Swiss 3T3 cells: Dissociation from protein kinase C activation

1987 ◽  
Vol 145 (3) ◽  
pp. 1026-1032 ◽  
Author(s):  
Huseyin Mehmet ◽  
Clive MG Morris ◽  
Joyce Taylor-Papadimitriou ◽  
Enrique Rozengurt
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Dna Synthesis ◽  
3T3 Cells ◽  
Kinase C ◽  
Swiss 3T3 ◽  
Inhibition Of Dna Synthesis ◽  
Protein Kinase C Activation
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