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Query: UMLS:C0043167 (
pertussis
)
19,595
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The effects of salmon calcitonin (sCT) and human calcitonin (hCT) and of rat (r) and human (h) calcitonin gene-related peptide (CGRP) on intracellular cAMP accumulation were tested in human breast cancer cells (MCF7). In addition to the well known stimulatory effect, each showed a significant inhibitory effect on cAMP accumulation at low doses. cAMP concentrations in response to sCT, hCT, and rCGRP decreased to 47 +/- 2, 45 +/- 4, and 56 +/- 2% (mean +/- 1 SE) of baseline. The potency ratios for the inhibitory action of sCT, hCT, and rCGRP (1:0.25:0.005, respectively) were similar to the potency ratios for stimulatory action (1:0.3:0.005). The inhibition of cAMP accumulation developed at 300-fold lower peptide concentrations than the stimulation. Preincubation with
pertussis
toxin or with manganese completely abolished the inhibitory effect of the peptides, suggesting that this is mediated by an inhibitory adenylate cyclase regulatory protein. sCT, hCT, and CGRP each showed unique patterns with regard to time course of inhibition of cAMP accumulation. We conclude that 1) CT can activate an inhibitory adenylate cyclase regulatory protein and a stimulatory adenylate cyclase regulatory protein, and 2) CT effect on an inhibitory adenylate cyclase regulatory protein in
MCF
7 cells is evident at far lower hormone concentrations than its effect on a stimulatory adenylate cyclase regulatory protein.
...
PMID:Dual effects of calcitonin and calcitonin gene-related peptide on intracellular cyclic 3',5'-monophosphate in a human breast cancer cell line. 283 Oct 23
The effect of estradiol treatment of the human mammary carcinoma cell
MCF
-7 on the adenylyl cyclase system was examined. Treatment with 10 nM estradiol for 72 h increased the basal level of cAMP, and isoproterenol-, PGE2- or calcitonin-stimulated cAMP production. Estradiol also increased the response to cholera toxin but did not alter the response to forskolin. No significant change in growth rate was observed during the 72 h of estradiol treatment. In
MCF
-7 cell membranes the responsiveness to isoproterenol, PGE2, or cholera toxin was also enhanced by estradiol treatment. The cholera toxin-catalyzed ADP-ribosylation of Gs alpha in
MCF
-7 cell membranes was significantly increased by 72 h of treatment with estradiol. Consistent with this observation, the level of Gs alpha immunoreactivity was increased in the estradiol-treated cell membranes. On the other hand,
pertussis
toxin did not change the responsiveness to isoproterenol, PGE2 or calcitonin in either control or estradiol-treated cells. In addition, ADP-ribosylation with
pertussis
toxin also did not reveal any change in Gi. These results clearly indicate that Gs expression is under the control of estradiol, and that this effect may contribute to the increased sensitivity of hormone-stimulated adenylyl cyclase activities in
MCF
-7 cells.
...
PMID:Estradiol up-regulates the stimulatory GTP-binding protein expression in the MCF-7 human mammary carcinoma cell line. 838 27
The pineal hormone, melatonin, inhibits proliferation of estrogen receptor (ER)-positive
MCF
-7 human breast cancer cells, modulates both ER mRNA and protein expression, and appears to be serum dependent, indicating interaction between melatonin and serum components. To examine the effects of melatonin on ER activity, ER transactivation assays were performed by transiently transfecting
MCF
-7 cells with an ERE-luciferase reporter construct.
MCF
-7 cells pre-treated with melatonin for as little as 5 min followed by either epidermal growth factor (EGF) or insulin resulted in the estrogen-independent transactivation of the ER. None of the compounds when used alone transactivated the ER. The ability of melatonin and EGF to transactivate the ER was abolished by the addition of the antiestrogen, ICI 164384, suggesting that melatonin and EGF co-operate to transactivate the ER. The modulation of ER transactivation was associated with changes in mitogen activated protein kinase activity and ER phosphorylation. This ER transactivation was blocked by
pertussis
toxin, a Galpha i-protein-coupled receptor inhibitor, suggesting cross talk between the G-protein-coupled melatonin receptor pathway and the EGF/insulin tyrosine kinase receptor pathways in modulating ER transactivation. Exactly how the ability of melatonin in combination with EGF to transactivate the ER relates to melatonin's observed growth suppressive effects is not clear. It is possible that, although melatonin and EGF transactivate the ER, this transactivation does not result in the full transcription of estrogen-responsive genes, but rather, makes the ER refractory to activation by estradiol, thus, blocking the mitogenic actions of estradiol.
...
PMID:Estrogen receptor transactivation in MCF-7 breast cancer cells by melatonin and growth factors. 972 86
Thrombospondin-1 (TSP1) is a matricellular protein that displays both pro- and anti-adhesive activities. Binding to sulfated glycoconjugates mediates most high affinity binding of soluble TSP1 to MDA-MB-435 cells, but attachment and spreading of these cells on immobilized TSP1 is primarily beta1 integrin-dependent. The integrin alpha3beta1 is the major mediator of breast carcinoma cell adhesion and chemotaxis to TSP1. This integrin is partially active in MDA-MB-435 cells but is mostly inactive in MDA-MB-231 and
MCF
-7 cells, which require beta1 integrin activation to induce spreading on TSP1. Integrin-mediated cell spreading on TSP1 is accompanied by extension of filopodia containing beta1 integrins. TSP1 binding activity of the alpha3beta1 integrin is not stimulated by CD47-binding peptides from TSP1 or by protein kinase C activation, which activate alphavbeta3 integrin function in the same cells. In MDA-MB-231 but not MDA-MB-435 cells, this integrin is activated by
pertussis
toxin, whereas serum, insulin, insulin-like growth factor-1, and ligation of CD98 increase activity of this integrin in both cell lines. Serum stimulation is accompanied by increased surface expression of CD98, whereas insulin-like growth factor-1 does not increase CD98 expression. Thus, the pro-adhesive activity of TSP1 for breast carcinoma cells is controlled by several signals that regulate activity of the alpha3beta1 integrin.
...
PMID:Pro-adhesive and chemotactic activities of thrombospondin-1 for breast carcinoma cells are mediated by alpha3beta1 integrin and regulated by insulin-like growth factor-1 and CD98. 1019 34
Phosphatidic acid (PA), lysophosphatidic acid (LPA), and sphingosine 1-phosphate (SPP) are naturally occurring phospholipids which induce a variety of effects as extracellular messengers. In this study, we compared the effects of these phospholipid signaling molecules on the migration of invasive and noninvasive breast cancer cell lines, an index of the metastatic potential of these cells. As previously demonstrated, invasive MDA-MB-231 breast cancer cells exhibited increased constitutive (nonstimulated) migration in comparison to poorly invasive
MCF
-7 cells. Phosphatidic acid employed at nanomolar concentrations markedly potentiated migration of the invasive cells but had no effect on migration of either the noninvasive
MCF
-7 cells or nonneoplastic human epithelial cells. Lysophosphatidic acid and sphingosine 1-phosphate inhibited both the directed (chemotactic) and random (chemokinetic) migration of MDA-MB-231 cells. Experiments were undertaken to characterize the signaling pathway involved in constitutive and PA-stimulated migration of MDA-MB-231 cells. The tyrosine kinase inhibitors staurosporine and genistein inhibited constitutive and PA-induced migration in a dose-dependent manner, consistent with a role for tyrosine phosphorylation in the migratory response. In addition, the phosphatidylinositol (PI) 3' kinase inhibitors wortmannin and LY294002 strongly inhibited both the constitutive and PA-stimulated migration of the invasive breast cancer cells, indicating that PI-3' kinase plays an important role in the metastatic migration of breast cancer cells. Finally, PA-induced migration of MDA-MB-231 was markedly attenuated by pretreatment of cells with Clostridium difficile Toxin B,
pertussis
toxin and suramin, implying a role for a Gi receptor-dependent process involving activation of the small GTP-binding protein Rho. Since an enhanced ability to migrate heightens the metastatic potential of cells within solid tumors, our results suggest that the metastatic capabilities of breast cancer cells may be enhanced by a receptor-driven cellular process initiated by phosphatidic acid or related lipid phosphate messengers.
...
PMID:Enhancement of the migration of metastatic human breast cancer cells by phosphatidic acid. 1067 29
We characterized anticancer effects of opioid analgesics that are clinically used for cancer patients for pain relief. Treatment with 100 microM buprenorphine, a representative analgesic, induced cell death of human carcinomas, such as A549 (squamous epithelial cell of lung cancer),
MCF
-7 (breast cancer) and N417 (small cell of lung cancer), but not in KATO III (gastric cancer) cells as evaluated by alamar blue assay. Among 18 clinically utilized and related analgesics, buprenorphine and loperamide showed potent inhibition of cell viability. However, these anti-cancer effects were not affected by opioid receptor antagonists nor by
pertussis
toxin. Buprenorphine-induced cell death occurred as early as 1 h after the addition, and its T1/2 of cell viability inhibition was 3 h. The cell death manifested the characteristics of apoptosis, such as DNA-laddering and nuclear fragmentation, which were sensitive to a caspase inhibitor, Z-Asp-CH2-DCB. The nuclear fragmentation was independent of cell cycle phase specificity. The activity of caspase-3-like protease which is known to be closely related to apoptotic DNA laddering was markedly enhanced by buprenorphine. However, the inhibition of cell viability by buprenorphine was not affected by the caspase inhibitor. These findings suggest that some opioid analgesics induce typical apoptotic features sensitive to the caspase inhibitor, while also inhibition of cell viability insensitive to the inhibitor.
...
PMID:Opioid analgesic-induced apoptosis and caspase-independent cell death in human lung carcinoma A549 cells. 1093 99
Estrogen rapidly activates the mitogen-activated protein kinases, Erk-1 and Erk-2, via an as yet unknown mechanism. Here, evidence is provided that estrogen-induced Erk-1/-2 activation occurs independently of known estrogen receptors, but requires the expression of the G protein-coupled receptor homolog, GPR30. We show that 17beta-estradiol activates Erk-1/-2 not only in
MCF
-7 cells, which express both estrogen receptor alpha (ER alpha) and ER beta, but also in SKBR3 breast cancer cells, which fail to express either receptor. Immunoblot analysis using GPR30 peptide antibodies showed that this estrogen response was associated with the presence of GPR30 protein in these cells. MDA-MB-231 breast cancer cells (ER alpha-, ER beta+) are GPR30 deficient and insensitive to Erk-1/-2 activation by 17beta-estradiol. Transfection of MDA-MB-231 cells with a GPR30 complementary DNA resulted in overexpression of GPR30 protein and conversion to an estrogen-responsive phenotype. In addition, GPR30-dependent Erk-1/-2 activation was triggered by ER antagonists, including ICI 182,780, yet not by 17alpha-estradiol or progesterone. Consistent with acting through a G protein-coupled receptor, estradiol signaling to Erk-1/-2 occurred via a Gbetagamma-dependent,
pertussis
toxin-sensitive pathway that required Src-related tyrosine kinase activity and tyrosine phosphorylation of tyrosine 317 of the Shc adapter protein. Reinforcing this idea, estradiol signaling to Erk-1/-2 was dependent upon trans-activation of the epidermal growth factor (EGF) receptor via release of heparan-bound EGF (HB-EGF). Estradiol signaling to Erk-1/-2 could be blocked by: 1) inhibiting EGF-receptor tyrosine kinase activity, 2) neutralizing HB-EGF with antibodies, or 3) down-modulating HB-EGF from the cell surface with the diphtheria toxin mutant, CRM-197. Our data imply that ER-negative breast tumors that continue to express GPR30 may use estrogen to drive growth factor-dependent cellular responses.
...
PMID:Estrogen-induced activation of Erk-1 and Erk-2 requires the G protein-coupled receptor homolog, GPR30, and occurs via trans-activation of the epidermal growth factor receptor through release of HB-EGF. 1104 79
The beta1 integrin-stimulating antibody TS2/16 induces cAMP-dependent migration of
MCF
-10A breast cells on the extracellular matrix protein laminin-5. TS2/16 stimulates a rise in intracellular cAMP within 20 min after plating.
Pertussis
toxin, which inhibits both antibody-induced migration and cAMP accumulation, targets the Galphai3 subunit of heterotrimeric G proteins in these cells, suggesting that Galphai3 may link integrin activation and migration via a cAMP signaling pathway.
...
PMID:Antibody-induced activation of beta1 integrin receptors stimulates cAMP-dependent migration of breast cells on laminin-5. 1117 Aug 44
Melatonin is a pineal hormone involved in neuroendocrine processes in mammals. It has been shown that melatonin inhibits the enzymatic activities of adenylyl cyclases and the transcriptional activities of CREB. In this report, we demonstrate that 2-iodomelatonin (2IMT) treatment on COS-7 cells transfected with melatonin receptors (mt1 and MT2) induces c-Jun N-terminal kinase (JNK) activation, which is
pertussis
toxin (PTX)-sensitive, Ras/Rac-dependent and may involve Src-family protein tyrosine kinases. Moreover, PTX-insensitive Gs, Gz and G16 are capable of linking activated melatonin receptors to the stimulation of JNK. Agonist stimulation on PTX-pretreated COS-7 cells overexpressing mt1 receptor, Galpha(s) and adenylyl cyclase VI led to increased cAMP accumulation. Stimulation of endogenous mt1 receptors in
MCF
-7 cells was associated with the activation of both JNK and extracellular signal-regulated kinase (ERK). This report demonstrates the stimulatory effect of melatonin receptors on JNK, and provides experimental evidence for a functional coupling between the G(i)-coupled melatonin receptor and Gs, in terms of adenylyl cyclase activation.
...
PMID:Melatonin mt1 and MT2 receptors stimulate c-Jun N-terminal kinase via pertussis toxin-sensitive and -insensitive G proteins. 1181 53
Insulin-like growth factor binding protein-3, IGFBP-3, specifically binds to IGFs with high affinity, but it is also capable of modulating the IGF-I signalling pathway or inducing apoptosis independently of its binding to IGFs. The molecular mechanisms underlying the action of IGFBP-3 have not been elucidated. In this study, we have demonstrated that binding of IGFBP-3 to a cell surface receptor in
MCF
-7 breast carcinoma cells induces a rapid and transient increase in intracellular free calcium. This increase was mediated via a
pertussis
toxin-sensitive pathway, indicating that the IGFBP-3 receptor may be specifically coupled to a Gi protein. The effect of IGFBP-3 on calcium concentrations was dose-dependent and also occurred when IGFBP-3 was complexed with either IGF-I or heparin, suggesting that the receptor binding site is probably located in the least conserved central domain of IGFBP-3. Neither IGFBP-1, nor IGFBP-5 (structurally the closest to IGFBP-3) altered intracellular calcium concentrations. These results provide evidence that a specific intracellular signal is triggered by IGFBP-3 binding to a cell surface receptor.
...
PMID:Insulin-like growth factor binding protein-3 increases intracellular calcium concentrations in MCF-7 breast carcinoma cells. 1222 Jun 77
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