Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0031511 (pheochromocytoma)
 14,622 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), an Ig-like transmembrane protein, functions in cell adhesion, angiogenesis and epithelial cell morphogenesis, and has been identified as a tumor suppressor. For all of these functions, CEACAM1 requires signaling capabilities. However, the mechanisms of CEACAM1-mediated signaling are only poorly understood. Here we characterized for the first time CEACAM1 expression and signaling in the neuroendocrine rat pheochromocytoma PC12 cell line. Stimulation of CEACAM1 by ligation on the cell surface with antibodies induced formation of large CEACAM1 clusters and a rapid and transient CEACAM1 tyrosine dephosphorylation. Functionally, this dephosphorylation correlated with a reduced association between CEACAM1 and the tyrosine phosphatase SHP2. Clustering also stimulated binding of CEACAM1 to the actin cytoskeleton, measured by a partial translocation of CEACAM1 into the insoluble fraction after detergent extraction. Both tyrosine dephosphorylation and interaction with the cytoskeleton were sensitive to neuronal differentiation of PC12 cells. The first detected downstream activation of the mitogen-activated protein kinases ERK1 and ERK2, but not of JNK or p38, describes a novel target of CEACAM1-mediated signaling and contributes to the understanding of how CEACAM1 regulates cellular function.
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PMID:Clustering-induced signaling of CEACAM1 in PC12 cells. 1210 45

The rat pheochromocytoma PC12 cells differentiate into neuronal-like cells in response to treatment with neurotrophins. The cells have been extensively used for investigating neuronal differentiation and axonal growth. Here we report the isolation of a variant PC12 cell line, named PC12-N1, which spontaneously differentiates and extends neuritic processes. The PC12-N1 cells expressed many neuronal specific proteins, including the synaptosomal associated protein of 25 kDa (SNAP-25), synaptotagmin, and synaptobrevin (also known as VAMP). The cells also expressed neurofilament protein of 68 kDa, a marker for differentiated neurons. In addition to the spontaneous neurite outgrowth, the PC12-N1 cells showed a marked increase in neurite outgrowth upon treatment with nerve growth factor (NGF), basic fibroblast growth factor (bFGF), and cyclic AMP (cAMP). The activation of mitogen-activated protein (MAP) kinases was examined by immunoblot analysis using phospho-specific antibodies. No overactivation was observed with ERK1/2 or p38. However, the c-Jun N-terminal kinase JNK/SAPK was activated approximately 10-fold over the parental PC12 cells. These results suggest that activation of JNK/SAPK may be involved in the spontaneous neurite extension in the PC12-N1 cells. Moreover, the PC12-N1 cells may be used as a model for investigating molecular signaling mechanisms underlying neuronal differentiation and axonal outgrowth.
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PMID:Variant PC12 cell line that spontaneously differentiates and extends neuritic processes. 1211 21

Activating mutations of the receptor tyrosine kinase, ret, are associated with multiple endocrine neoplasia type 2A (MEN 2A). However, the mechanisms leading to tumor development are unclear. Glial-derived neurotrophic factor (GDNF) activates wild-type ret via interaction with a second receptor, GFR a-l. We have utilized GDNF to stimulate normal and neoplastic chromaffin cells in order to ask whether ret activation is mitogenic. Cells from three normal adult adrenal medullas, one sporadic pheochromocytoma, and three MEN-2A pheochromocytomas were labeled with bromodeoxyuridine (BrdU) for 12 d in the presence or absence of GDNF or nerve growth factor (NGF), which is known to stimulate neurite outgrowth, but not proliferation in human chromaffin and pheochromocytoma cell cultures. Responses to GDNF and NGF were comparable, except for two MEN-2A pheochromocytomas that responded minimally to GDNF and robustly to NGF. These tumors responded to GDNF biochemically, as measured by phosphorylation of mitogen-activated protein kineses, despite their weak morphological responses. Our findings suggest that activation of ret may not be sufficient to produce chromaffin cell hyperplasia or neoplasia directly by stimulating cell proliferation. However the possibility that altered cell-cell or cell-substrate interactions might cause responses to become differ entiative rather than proliferative in vitro has not been ruled out. We also demonstrate, for the first time, that at least some human pheochromocytomas with an MEN-2A ret mutation respond to a normal ret ligand. This responsiveness could be mediated by a remaining normal ret allele or by other mechanisms.
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PMID:The ret-Activating Ligand GDNF Is Differentiative and Not Mitogenic for Normal and Neoplastic Human Chromaffin Cells In Vitro. 1211 80

Adrenomedullin, originally discovered in human pheochromocytoma, has been shown to have potent vasodilatory activity. However, like other vasoactive peptide hormones, its physiological roles have been found to extend far beyond the regulation of vascular tonus, and to include such functions as the regulation of cell proliferation and differentiation. There is a growing body of evidence that adrenomedullin exerts a wide range of effects on cell growth and apoptotic death, and that these effects are dependent on cell type and experimental conditions. Signaling pathways independent of cyclic AMP, such as protein tyrosine kinase(s) and mitogen-activated protein kinases, may play key roles in the regulation of mitogenesis and apoptosis by adrenomedullin.
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PMID:Regulation of cell growth and apoptosis by adrenomedullin. 1263 Aug 6

Secretin evokes catecholamine secretion from PC12 pheochromocytoma cells. We tested whether secretin activates transcription of the major vesicular core protein chromogranin A (CgA). Secretin stimulated both endogenous CgA gene transcription (approximately 4-6-fold) as well as transfected CgA promoter activity (approximately 8-10-fold; EC50, approximately 7 nm) in PC12 cells. Studies on CgA promoter 5'-deletion mutant/luciferase reporter constructs, point mutations of the CgA cAMP response element (CRE), and their transfer to a heterologous promoter implicated CRE in cis as both necessary and sufficient for secretin-stimulated CgA gene transcription. Secretin-induced CgA gene transcription was inhibited/abolished by cytosolic Ca2+ chelation, chemical blockade of phospholipase C, protein kinase A (PKA), or mitogen-activated protein (MAP) kinase extracellular signal regulated kinase (ERK) 1/2 and the expression of dominant negative mutants of ERK1/2, CRE binding protein (CREB) kinase RSK2, or CREB. Secretin also augmented (approximately 4-fold) phosphorylation of ERK1/2. Trans-activation (approximately 21-fold) of GAL4-CREB fusion protein by secretin indicates involvement of CREB in secretin signaling to gene transcription. Electrophoretic mobility shift assays also identified CREB as the mediator of secretin-induced CgA gene transcription, and pCREB supershifts indicated Ser-133 as the active CREB moiety in vitro. This conclusion was reinforced in vivo by results of chromatin pCREB immunoprecipitation assays. We conclude that secretin signals to CgA gene transcription through the CRE domain in cis and through cAMP, Ca2+, PKA, MAP kinase, and the transcription factor CREB in trans. Thus, multiple signal transduction pathways seem to subserve the function of stimulus-transcription coupling after this peptidergic stimulus to chromaffin cells.
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PMID:Secretin activation of chromogranin A gene transcription. Identification of the signaling pathways in cis and in trans. 1264 81

Neurotrophins such as nerve growth factor (NGF) are considered putative neuroprotective compounds in the central nervous system. To investigate the cellular and molecular neuroprotective mechanisms of NGF under ischemia, we used a unique oxygen and glucose deprivation (OGD) device. In this system we used pheochromocytoma PC12 cells to elucidate NGF neuroprotective effect. PC12 cells were exposed to OGD, followed by addition of glucose and oxygen (OGD reperfusion). Neuronal cell death induced in this model was measured by the release of lactate dehydrogenase (LDH), activation of caspase-3 and mitogen-activated protein kinases (MAPKs), measured with specific anti-phospho-antibodies. Pretreatment of the cultures with 50 ng/mL NGF, 18 h prior to OGD insult, conferred 30% neuroprotection. However, treatment of the cultures with NGF concomitantly with the OGD insult did not result in neuroprotection. Time-course experiments showed marked activation of extracellular signal-regulated protein kinase, c-Jun N-terminal kinase (JNK), and p38 MAPK isoforms during the OGD phase but not during OGD reperfusion. Pretreatment of the cultures with 50 ng/mL NGF, 18 h prior to OGD insult, resulted in 50% attenuation of OGD-induced activation of JNK1, and 20% and 50% attenuation of OGD-induced activation of p38alpha and beta, respectively. These findings support the notion that NGF confers neuroprotection from OGD insult, a phenomenon coincidentally related to differential inhibition of MAPK stress kinase isoforms, and provide the PC12 model as an in vitro OGD system to investigate molecular mechanisms of neurotoxicity and neuroprotection.
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PMID:Nerve growth factor pretreatment attenuates oxygen and glucose deprivation-induced c-Jun amino-terminal kinase 1 and stress-activated kinases p38alpha and p38beta activation and confers neuroprotection in the pheochromocytoma PC12 Model. 1499 18

Tetrahydropapaveroline (THP), a dopamine-derived tetrahydroisoquinoline catechol, has been suspected to be dopaminergic neurotoxin that elicits parkinsonism and neurobehavioral abnormalities associated with chronic alcoholism. THP has been detected in the brains of parkinsonian patients, and its urinary as well as brain level increases after l-3,4-dihydroxyphenylalanine treatment. Autoxidation or enzymatic oxidation of THP and subsequent generation of reactive oxygen species (ROS) may contribute to the degeneration of dopaminergic neurons induced by this tetrahydroisoquinoline alkaloid. In the present study, THP was found to elicit cytotoxicity in cultured rat pheochromocytoma (PC12) cells, which was completely blocked by reduced glutathione and N-acetyl-L-cysteine. THP-treated PC12 cells exhibited increased intracellular accumulation of ROS and underwent apoptosis as determined by poly(ADP-ribose)polymerase cleavage, an increased ratio of Bax to BclxL, terminal transferase-mediated dUTP nick end labeling, and nuclear fragmentation or condensation. THP treatment caused activation of the redox-sensitive transcription factor nuclear factor kappaB (NF-kappaB). Pretreatment of PC12 cells with NF-kappaB inhibitors, such as l-1-tosylamido-2-phenylethyl chloromethyl ketone and parthenolide, aggravated THP-induced cell death. THP treatment resulted in differential activation of mitogen-activated protein kinases as well as Akt/protein kinase B, thereby transmitting cell survival or death signals. In conclusion, THP induces apoptosis in PC12 cells by generating ROS. THP-mediated oxidative stress was accompanied by differential activation of intracellular signaling kinases and NF-kappaB.
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PMID:Potential roles of NF-kappaB and ERK1/2 in cytoprotection against oxidative cell death induced by tetrahydropapaveroline. 1508 72

Although several multiprotein complexes containing MAPKs (mitogen-activated protein kinases) have been identified using overexpression of kinases and scaffold proteins, the components of the complexes and their physical properties at endogenous expression levels have not been defined. We characterized a large protein complex containing a nerve-growth-factor-activated ERK (extracellular-signal-regulated kinase) and MEK (MAPK/ERK kinase) in rat pheochromocytoma (PC12) cells. This protein complex fractionated into a high-speed pellet and was resistant to non-ionic detergent treatments that solubilized membranes. Disruption of protein-protein interactions by treatment with high salt was required to facilitate immunoprecipitation of active ERK1 and co-precipitation of MEK1. Microtubule fragments were also present in the detergent-resistant high-speed pellet, and some kinases were bound to them, especially ERK1b (an alternatively spliced isoform of ERK1), which showed a strong preference for binding microtubules. The large protein complex containing ERK1 and MEK1 was resolved by velocity sedimentation from fragments of microtubules; however, it did not contain other scaffolding components known to bind ERK and MEK. B-Raf was also present in a distinct detergent-resistant, microtubule-independent protein complex slightly larger than that containing ERK and MEK. We conclude that there are two independent nerve growth factor-regulated 'signalling particles' with an estimated size of 60-75 S, one containing ERK1 and MEK1 and the other containing B-Raf. These signalling particles may have a role in the temporal and spatial regulation of kinase activity inside cells.
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PMID:Distinct signalling particles containing ERK/MEK and B-Raf in PC12 cells. 1550 Apr 39

Rit is one of the original members of a novel Ras GTPase subfamily that uses distinct effector pathways to transform NIH 3T3 cells and induce pheochromocytoma cell (PC6) differentiation. In this study, we find that stimulation of PC6 cells by growth factors, including nerve growth factor (NGF), results in rapid and prolonged Rit activation. Ectopic expression of active Rit promotes PC6 neurite outgrowth that is morphologically distinct from that promoted by oncogenic Ras (evidenced by increased neurite branching) and stimulates activation of both the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinase signaling pathways. Furthermore, Rit-induced differentiation is dependent upon both MAP kinase cascades, since MEK inhibition blocked Rit-induced neurite outgrowth, while p38 blockade inhibited neurite elongation and branching but not neurite initiation. Surprisingly, while Rit was unable to stimulate ERK activity in NIH 3T3 cells, it potently activated ERK in PC6 cells. This cell type specificity is explained by the finding that Rit was unable to activate C-Raf, while it bound and stimulated the neuronal Raf isoform, B-Raf. Importantly, selective down-regulation of Rit gene expression in PC6 cells significantly altered NGF-dependent MAP kinase cascade responses, inhibiting both p38 and ERK kinase activation. Moreover, the ability of NGF to promote neuronal differentiation was attenuated by Rit knockdown. Thus, Rit is implicated in a novel pathway of neuronal development and regeneration by coupling specific trophic factor signals to sustained activation of the B-Raf/ERK and p38 MAP kinase cascades.
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PMID:Rit contributes to nerve growth factor-induced neuronal differentiation via activation of B-Raf-extracellular signal-regulated kinase and p38 mitogen-activated protein kinase cascades. 1563 82

We have previously shown that prolactin-releasing peptide (PrRP) stimulates catecholamine release from PC12 cells (rat pheochromocytoma cell line). However, it is not known whether PrRP also affects catecholamine biosynthesis. Thus, we examined the effect of PrRP on catecholamine biosynthesis in PC12 cells. PrRP31 (>10 nM) and PrRP20 (>100 nM) significantly increased the activity and expression level of tyrosine hydroxylase (TH), a rate-limiting enzyme, in catecholamine biosynthesis. However, the PrRP20-stimulated TH activity was markedly weaker than that of PrRP31. PrRP31 (>1 nM) and PrRP20 (>10 nM) significantly induced an increase in the level of PKC activity. Both Ro 32-0432 (a protein kinase C inhibitor) and H89 (a protein kinase A inhibitor) effectively suppressed the PrRP31 (100 nM)-induced TH mRNA level. Next, we examined the effect of PrRP on mitogen-activated protein kinases (MAPKs). PrRP31 (1 microM) significantly induced an increase in the activity of extracellular signal-related kinases (ERKs) and the stress-activated protein kinase/c-jun N terminal kinase (SAPK/JNK). In contrast to ERKs and JNK, PrRP31 did not affect P38 MAPK activity. Consistent with these findings, pretreatment of cells with the MEK-1-inhibitor, PD-98059 (50 microM), significantly inhibited the PrRP31 (100 nM)-induced increase in TH mRNA. These results indicate that PrRP stimulates catecholamine synthesis through both the PKC and PKA pathways in PC12 cells.
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PMID:Stimulation of catecholamine biosynthesis via the PKC pathway by prolactin-releasing peptide in PC12 rat pheochromocytoma cells. 1600 52


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