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At least 865 records · Page 48Linked to original sources
PubMed2005

Allosteric potentiators of metabotropic glutamate receptor subtype 5 have differential effects on different signaling pathways in cortical astrocytes.

The metabotropic glutamate receptor subtype 5 (mGluR5) activates calcium mobilization and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in cortical astrocytes. These are independent signaling systems, and they can be differentially regulated. We recently discovered two novel selective allosteric potentiators of mGluR5, 3,3'-difluorobenzaldazine (DFB) and N-{4-chloro-2-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl) methyl]phenyl}-2-hydroxybenzamide (CPPHA). In studies of mGluR5 activation of calcium transients in recombinant systems, both DFB and CPPHA are without effect on baseline calcium levels, but they induce parallel leftward shifts in the concentration-response curve to agonists. However, it is conceivable that these compounds will have differential effects on different signaling pathways in native systems. Here, we examined the effects of CPPHA and DFB on mGluR5-induced calcium transients and ERK1/2 phosphorylation in cultured rat cortical astrocytes. Both potentiators induced parallel leftward shifts of the concentration-response curves of DHPG- and glutamate-induced calcium transients in astrocytes. These effects are identical to their effects on mGluR5 expressed in human embryonic kidney 293 or Chinese hamster ovary cells. DFB induced a similar shift of concentration-response curve of DHPG-induced ERK1/2 phosphorylation. Interestingly, CPPHA induced an increase in basal mGluR5-mediated ERK1/2 phosphorylation and potentiated the effect of low concentrations of agonists. In contrast, CPPHA significantly decreased ERK1/2 phosphorylation induced by high concentrations of agonists. Thus, CPPHA has qualitatively different effects on mGluR5-mediated calcium responses and ERK1/2 phosphorylation. Together, these data provide evidence that different allosteric potentiators can differentially modulate coupling of a single receptor to different signaling pathways.

Allosteric Regulation↗
PubMed2000

Chat, a Cas/HEF1-associated adaptor protein that integrates multiple signaling pathways.

Cas (Crk-associated substrate) and HEF1 (human enhancer of filamentation) are related adaptor proteins that function in integrin-mediated cell adhesion and antigen receptor signaling pathways. We report here a molecular cloning of Chat (Cas/HEF1-associated signal transducer) that associates with Cas and HEF1. Chat is a 78-kDa signaling molecule with an N-terminal SH2 domain and is expressed in a wide range of tissues. In hematopoietic cells, a 115-kDa isoform of Chat (Chat-H) was specifically expressed. Chat is associated with Cas in brain, and Chat-H is associated with HEF1 in splenocytes. Deletion analyses revealed that Chat and Cas are associated with each other by their C-terminal domains. Treatment of PC12 cells with epidermal growth factor or nerve growth factor increased the phosphorylation level of Chat. This increase was suppressed by an inhibitor of mitogen-activated protein (MAP) kinase kinase, PD98059, suggesting the phosphorylation of Chat by MAP kinase. In Chat-overexpressed COS7 cells, the activity of c-Jun N-terminal kinase was up-regulated. After the epidermal growth factor stimulation, Chat and Cas were colocalized with actin filaments at ruffling membranes. These findings suggest that Chat transduces signals of tyrosine kinases and MAP kinase to Cas signaling pathway.

Actins↗
PubMed2005

Extramammary Paget's disease: analysis of growth signal pathway from the human epidermal growth factor receptor 2 protein.

Paget's disease is a skin cancer characterized by characteristic (Paget) cells scattered in the epidermis. Although its prognosis is generally favorable with surgical resection, the clinical outcome turns unfavorable in cases with recurrence and metastasis. Therefore, establishment of effective therapeutic regimens is required for advanced Paget's disease. The human epidermal growth factor receptor 2 (HER2) protein, a transmembrane growth factor receptor, is frequently overexpressed in malignancies, causing activation of the phosphatidylinositol 3 kinase (PI3K) and extracellular signal-regulated kinase (ERK) signal pathways. Recently, HER2-targeting molecular therapy using trastuzumab (Herceptin; Genentech, Inc, South San Francisco, Calif) was revealed to be effective in advanced breast cancers overexpressing HER2 protein. Here, we analyzed the correlation between activation of the HER2 signal pathways and clinicopathologic parameters of 36 extramammary Paget's disease samples from 34 Japanese patients, using immunohistochemical analyses for HER2, phosphorylated HER2, phosphorylated AKT, and phosphorylated ERK proteins. We found overexpression of the HER2 protein in 19.4% (7) of the lesions, 3 of which showed HER2 amplification by chromogenic in situ hybridization. Phosphorylated HER2 protein was detected in 12 lesions (33.3%), including 2 of the 7 HER2-overexpressing lesions. Phosphorylated AKT was detected in approximately 75.0% (27/36) and phosphorylated ERK in 38.9% (14/36). Both HER2 and AKT were simultaneously phosphorylated in 9 cases (25.0%) and HER2 and ERK in 9 cases (25.0%), but all 3 molecules were phosphorylated in only 1 sample. Phosphorylated ERK correlated with the maximum diameter of the tumors (P < .025), but other immunohistochemical parameters failed to show any correlation with clinicopathologic features. These results suggest the contribution of the HER2 signaling pathway to the pathogenesis and progression of some cases of extramammary Paget's disease, for which clinical use of molecular target therapy against the HER2 pathway is warranted.

Aged↗
PubMed2002

Sequential activation of signaling pathways during innate immune responses in Drosophila.

Innate immunity is essential for metazoans to fight microbial infections. Genome-wide expression profiling was used to analyze the outcome of impairing specific signaling pathways after microbial challenge. We found that these transcriptional patterns can be dissected into distinct groups. We demonstrate that, in addition to signaling through the Toll and Imd pathways, signaling through the JNK and JAK/STAT pathways controls distinct subsets of targets induced by microbial agents. Each pathway shows a specific temporal pattern of activation and targets different functional groups, suggesting that innate immune responses are modular and recruit distinct physiological programs. In particular, our results may imply a close link between the control of tissue repair and antimicrobial processes.

Animals↗
PubMed1996

Inhibition of cytokines and JAK-STAT activation by distinct signaling pathways.

An important component of cytokine regulation of cell growth and differentiation is rapid transcriptional activation of genes by the JAK-STAT (signal transducer and activator of transcription) signaling pathway. Ligation of cytokine receptors results in tyrosine phosphorylation and activation of receptor-associated Jak protein tyrosine kinases and cytoplasmic STAT transcription factors, which then translocate to the nucleus. We describe the interruption of cytokine triggered JAK-STAT signals by cAMP, the calcium ionophore ionomycin, and granulocyte/macrophage colony-stimulating factor. Jak1 kinase activity, interleukin 6-induced gene activation, Stat3 tyrosine phosphorylation, and DNA-binding were inhibited, as was activation of Jak1 and Stat1 by interferon gamma. The kinetics and requirement for new RNA and protein synthesis for inhibition of interleukin 6 by ionomycin and GM-CSF differed, but both agents increased the association of Jak1 with protein tyrosine phosphatase ID (SH2-containing phosphatase 2). Our results demonstrate that crosstalk with distinct signaling pathways can inhibit JAK-STAT signal transduction, and suggest approaches for modulating cytokine activity during immune responses and inflammatory processes.

Blotting, Northern↗
PubMed2001

Signaling pathways activated by the growth hormone receptor.

In recent years, significant progress has been made in elucidating the signaling pathways activated by the growth hormone (GH) receptor. An initiating event is probably the activation of JAK2 (Janus kinase 2), a GH receptor-associated tyrosine kinase. Identification of the proteins recruited to the GH receptor-JAK2 complex and dissection of the signaling pathways that are subsequently activated will ultimately provide a basis for understanding GH action at the molecular level.

Animals↗
PubMed1998

Growth factor receptor tyrosine kinases acutely regulate neuronal sodium channels through the src signaling pathway.

Growth factor receptor tyrosine kinase (RTK)-activated signaling pathways are well established regulators of neuronal growth and development, but whether these signals provide mechanisms for acute modulation of neuronal activity is just beginning to be addressed. We show in pheochromocytoma (PC12) cells that acute application of ligands for both endogenous RTKs [trkA, basic FGF (bFGF) receptor, and epidermal growth factor (EGF) receptor] and ectopically expressed platelet-derived growth factor (PDGF) receptors rapidly inhibits whole-cell sodium channel currents, coincident with a hyperpolarizing shift in the voltage dependence of inactivation. Sodium channel inhibition by trkA and PDGF receptors is mutually occlusive, suggestive of a common signal transduction mechanism. Furthermore, specific inhibitors for trkA and PDGF RTK activities abrogate sodium channel inhibition in response to NGF and PDGF, respectively, showing that the intrinsic RTK activity of these receptors is necessary for sodium channel inhibition. Use of PDGF receptor mutants deficient for specific signaling activities demonstrated that this inhibition is dependent on RTK interaction with Src but not with other RTK-associated signaling molecules. Inhibition was also compromised in cells expressing dominant-negative Ras. These results suggest a possible mechanism for acute physiological actions of RTKs, and they indicate regulatory functions for Ras and Src that may complement the roles of these signaling proteins in long-term neuronal regulation.

Animals↗
PubMed2001

Cytoplasmic signaling pathways that regulate cardiac hypertrophy.

This review discusses the rapidly progressing field of cardiomyocyte signal transduction and the regulation of the hypertrophic response. When stimulated by a wide array of neurohumoral factors or when faced with an increase in ventricular-wall tension, individual cardiomyocytes undergo hypertrophic growth as an adaptive response. However, sustained cardiac hypertrophy is a leading predictor of future heart failure. A growing number of intracellular signaling pathways have been characterized as important transducers of the hypertrophic response, including specific G protein isoforms, low-molecular-weight GTPases (Ras, RhoA, and Rac), mitogen-activated protein kinase cascades, protein kinase C, calcineurin, gp130-signal transducer and activator of transcription, insulin-like growth factor I receptor pathway, fibroblast growth factor and transforming growth factor beta receptor pathways, and many others. Each of these signaling pathways has been implicated as a hypertrophic transducer, which collectively suggests an emerging paradigm whereby multiple pathways operate in concert to orchestrate a hypertrophic response

Animals↗
PubMed2003

Stem cell-derived endothelial cells/progenitors migrate and pattern in the embryo using the VEGF signaling pathway.

Endothelial precursor cells respond to molecular cues to migrate and assemble into embryonic blood vessels, but the signaling pathways involved in vascular patterning are not well understood. We recently showed that avian vascular patterning cues are recognized by mammalian angioblasts derived from somitic mesoderm through analysis of mouse-avian chimeras. To determine whether stem cell-derived endothelial cells/progenitors also recognize global patterning signals, murine ES cell-derived embryoid bodies (EBs) were grafted into avian hosts. ES cell-derived murine endothelial cells/progenitors migrated extensively and colonized the appropriate host vascular beds. They also formed mosaic vessels with avian endothelial cells. Unlike somite derived-endothelial cells, ES cell-derived endothelial cells/progenitors migrated across the host embryonic midline to the contralateral side. To determine the role of VEGF signaling in embryonic vascular patterning, EBs mutant for a VEGF receptor (flk-1(-/-)) or a signal (VEGF-A(-/-)) were grafted into quail hosts. Flk-1(-/-) EB grafts produced only rare endothelial cells that did not migrate or assemble into vessels. In contrast, VEGF-A(-/-) EB grafts produced endothelial cells that resembled wild-type and colonized host vascular beds, suggesting that host-derived signals can partially rescue mutant graft vascular patterning. VEGF-A(-/-) graft endothelial cells/progenitors crossed the host midline with much lower frequency than wild-type EB grafts, indicating that graft-derived VEGF compromised the midline barrier when present. Thus, ES cell-derived endothelial cells/progenitors respond appropriately to global vascular patterning cues, and they require the VEGF signaling pathway to pattern properly. Moreover, EB-avian chimeras provide an efficient way to screen mutations for vascular patterning defects.

Animals↗
PubMed2006

Apoptosis signaling pathway in a subtotal nephrectomy rat model.

To investigate the role and mechanisms of apoptosis and apoptosis signaling pathway in 5/6 nephrectomy rat model (SN(x)), the mRNA and protein levels of caspase-3, -8, -9 and apoptosis were detected by in situ end labeling (TUNEL), immunohistochemistry, RT-PCR, Western-blotting 1, 2, 4, 8, 12, 16, 26 and 40 weeks after 5/6 nephrectomy rat model was made respectively. The rats in the model group developed glomerular sclerosis and renal interstitial fibrosis. The number of the apoptototic cells in glomeruli, renal tubule and renal interstitium was remarkably higher in the model group than that in the control group (P < 0.05, P < 0.01). Changes of mRNA and protein level of caspase-3, -8, -9 had the same tendency and was up-regulated wavily in the rat model compared with the control group (P < 0.05). Peaks in model appeared on the 4th and the 40th week respectively. The growth amplitude of caspase-9 was remarkably higher than that of caspase-8. It is concluded that the development of 5/6 nephrectomy rat model was correlated with the apoptosis of glomeruli, renal tubule and renal interstitium. Both of death receptor and mitochondria signaling pathways are involved in the process and the latter might play a primary role.

Animals↗
PubMed2004

Two distinct signaling pathways participate in auxin-induced swelling of pea epidermal protoplasts.

Protoplast swelling was used to investigate auxin signaling in the growth-limiting stem epidermis. The protoplasts of epidermal cells were isolated from elongating internodes of pea (Pisum sativum). These protoplasts swelled in response to auxin, providing the clearest evidence that the epidermis can directly perceive auxin. The swelling response to the natural auxin IAA showed a biphasic dose response curve but that to the synthetic auxin 1-naphthalene acetic acid (NAA) showed a simple bell-shaped dose response curve. The responses to IAA and NAA were further analyzed using antibodies raised against ABP1 (auxin-binding protein 1), and their dependency on extracellular ions was investigated. Two signaling pathways were resolved for IAA, an ABP1-dependent pathway and an ABP1-independent pathway that is much more sensitive to IAA than the former. The response by the ABP1 pathway was eliminated by anti-ABP1 antibodies, had a higher sensitivity to NAA, and did not depend on extracellular Ca(2+). In contrast, the response by the non-ABP1 pathway was not affected by anti-ABP1 antibodies, had no sensitivity to NAA, and depended on extracellular Ca(2+). The swelling by either pathway required extracellular K(+) and Cl(-). The auxin-induced growth of pea internode segments showed similar response patterns, including the occurrence of two peaks in the dose response curve for IAA and the difference in Ca(2+) requirements. It is suggested that two signaling pathways participate in auxin-induced internode growth and that the non-ABP1 pathway is more likely to be involved in the control of growth by constitutive concentrations of endogenous auxin.

Calcium↗
PubMed2004

Significance of the Rac signaling pathway in HCC cell motility: implications for a new therapeutic target.

Recurrence and metastasis are commonly associated with poor prognosis of hepatocellular carcinoma (HCC). Therefore, a better understanding of molecular mechanisms involved in HCC metastasis may lead to more effective treatment for HCC patients. Rac plays important roles in cytoskeletal reorganization leading to cell motility in renal and breast carcinomas. However, the role of Rac is controversial in tumors and has not been studied in HCC. The aim of this study was to investigate the importance of the Rac signaling pathway in HCC cell motility and the anti-metastatic potential of FTY720. Recently a pair of HCC cell lines from a primary tumor (H2P) and its matched metastasis (H2M) was established. These two cell lines provide a useful tool for the study of HCC metastasis. The results show that the Rac signaling pathway is activated in the metastatic HCC cell line (H2M) compared with the primary HCC cell line (H2P). FTY720 specifically suppressed H2M cell motility by down-regulation of the Rac-GTP level through inhibition of phosphoinositide 3-kinase activity. To conclude, this study is the first to demonstrate an essential role of Rac signaling pathway activation in HCC metastasis and suppression of cell motility by FTY720 through blocking of the Rac pathway.

Carcinoma, Hepatocellular↗
PubMed2002

Rac is activated by erythropoietin or interleukin-3 and is involved in activation of the Erk signaling pathway.

Previous studies have shown that hematopoietic cytokines, including erythropoietin (Epo) and interleukin (IL)-3, activate the Ras GTPase and the downstream Raf/Erk/Elk-1 signaling pathway. Here we report that Epo or IL-3 rapidly and transiently activates Rac, a Rho family GTPase, in hematopoietic cell lines, 32D/EpoR-Wt and UT-7. The cytokine-induced activation of Rac was augmented in a 32D/EpoR-Wt clone that inducibly overexpresses the adaptor protein CrkL or the Ras guanine nucleotide exchange factor C3G, which forms a complex with CrkL. Furthermore, the Rac activation was enhanced or inhibited in cells inducibly expressing an activated Ras mutant, H-Ras61L, or a dominant negative Ras mutant, H-Ras17N, respectively. In addition, the cytokine-induced Rac activation was inhibited by a phosphatidyl-inositol 3'-kinase (PI3K) inhibitor, LY294002, which also inhibited the Erk activation. A dominant negative Rac mutant, Rac17N, also inhibited the cytokine-induced activation of Erk as well as Elk-1. On the other hand, activation of Akt downstream of PI3K was found to play an inhibitory role in cytokine activation of Erk/Elk-1. Together, these results indicate that Rac is activated by Epo or IL-3 at downstream of the Ras/PI3K pathway in parallel with Akt and plays a role in activation of the Erk/Elk-1 signaling pathway in hematopoietic cells.

Adaptor Proteins, Signal Transducing↗
PubMed1999

HGF triggers activation of the COX-2 gene in rat gastric epithelial cells: action mediated through the ERK2 signaling pathway.

Although it is established that growth factors and prostaglandins function in the maintenance of gastric mucosal integrity and in the healing of gastric mucosal injury and ulceration, the regulatory relationship between growth factors and prostaglandins in the gastric mucosa is not well characterized. Therefore, we investigated whether hepatocyte growth factor (HGF) affects expression of COX-2 (the inducible form of the prostaglandin synthesizing enzyme, cyclooxygenase) in gastric epithelial cells and whether this action is mediated through the MAP (ERK) kinase signaling pathway. In RGM1 cells (an epithelial cell line derived from normal rat gastric mucosa), HGF caused an increase in COX-2 mRNA and protein by 236% and 175%, respectively (both P<0.05). This induction of COX-2 expression was abolished by pretreatment with the MAPK kinase (MEK) inhibitor PD98059. HGF also triggered a 13-fold increase in c-Met/HGF receptor phosphorylation (P<0.005) and increased ERK2 activity by 684% (P<0.01). Pretreatment with PD98059 abolished the HGF-induced increase in ERK2 activity, but not c-Met/HGF receptor phosphorylation. The specific inhibitor of p38 MAP kinase, SB203580, had no effect on HGF-induced COX-2 expression. Thus, HGF triggers activation of the COX-2 gene in gastric epithelial cells through phosphorylation of c-Met/HGF receptor and activation of the ERK2 signaling pathway.-Jones, M. K., Sasaki, E., Halter, F., Pai, R., Nakamura, T., Arakawa, T., Kuroki, T., Tarnawski, A. S. HGF triggers activation of the COX-2 gene in rat gastric epithelial cells: action mediated through the ERK2 signaling pathway.

Animals↗
PubMed2002

Coxsackievirus B3 replication is reduced by inhibition of the extracellular signal-regulated kinase (ERK) signaling pathway.

Coxsackievirus B3 (CVB3) is the most common human pathogen for viral myocarditis. We have previously shown that the signaling protein p21(ras) GTPase-activating protein (RasGAP) is cleaved and that mitogen-activated protein kinases (MAPKs) ERK1/2 are activated in the late phase of CVB3 infection. However, the role of intracellular signaling pathways in CVB3-mediated myocarditis and the relative advantages of such pathways to host or virus remain largely unclear. In this study we extended our prior studies by examining the interaction between CVB3 replication and intracellular signaling pathways in HeLa cells. We observed that CVB3 infection induced a biphasic activation of ERK1/2, early transient activation versus late sustained activation, which were regulated by different mechanisms. Infection by UV-irradiated, inactivated virus capable of receptor binding and endocytosis triggered early ERK1/2 activation, but was insufficient to trigger late ERK1/2 activation. By using a general caspase inhibitor (zVAD.fmk) we further demonstrated that late ERK1/2 activation was not a result of CVB3-mediated caspase cleavage. Treatment of cells with U0126, a selective inhibitor of MAPK kinase (MEK), significantly inhibited CVB3 progeny release and decreased virus protein production. Furthermore, inhibition of ERK1/2 activation circumvented CVB3-induced apoptosis and viral protease-mediated RasGAP cleavage. Taken together, these data suggest that ERK1/2 activation is important for CVB3 replication and contributes to virus-mediated changes in host cells. Our findings demonstrate coxsackievirus takeover of a particular host signaling mechanism and uncover a prospective approach to stymie virus spread and preserve myocardial integrity.

Amino Acid Chloromethyl Ketones↗
PubMed2000

[The modulating effect of panax pseudoginseng wall saponins on the DAG-PKC signal pathway and TNF secretion of macrophages].

OBJECTIVE: To explore the roles of panax pseudoginseng wall saponins on the DAG-PKC signal pathway and TNF secretion of macrophages. METHODS: The changes of the activities of postburn inositol lipid signal system factors such as PLC, DAG, cytomembrane PKC, cytoplasma PKC, and intracellular calcium concentration and the secretory amount of macrophage TNF were observed. RESULTS: Panax pseudoginseng wall saponins could reduce the increased PLC activity from 57.58 +/- 8.19 to 27.00 +/- 2.31 and the intracellular calcium concentration from 393.18 +/- 392.62 to 90.56 +/- 7.21. With the role of panax pseudoginseng wall saponins, DAG activity reduced from 488.10 +/- 40.20 to 288.30 +/- 30.00, cytomembrane PKC activity decreased from 3081.50 +/- 698.50 to 1699.50 +/- 218.50, and cytoplasmic PKC activity from 2 188.60 +/- 258.30 to 848.40 +/- 138.30. The secretory TNF amount of macrophage decreased by 55%. CONCLUSION: Panax pseudoginseng wall saponins might play an very important role in the modulating of the DAG-PKC signal pathway and decreased TNF secretion of macrophage.

Animals↗
PubMed2000

Convergence of dorsal, dpp, and egfr signaling pathways subdivides the drosophila neuroectoderm into three dorsal-ventral columns.

An important question in neurobiology is how different cell fates are established along the dorsoventral (DV) axis of the central nervous system (CNS). Here we investigate the origins of DV patterning within the Drosophila CNS. The earliest sign of neural DV patterning is the expression of three homeobox genes in the neuroectoderm-ventral nervous system defective (vnd), intermediate neuroblasts defective (ind), and muscle segment homeobox (msh)-which are expressed in ventral, intermediate, and dorsal columns of neuroectoderm, respectively. Previous studies have shown that the Dorsal, Decapentaplegic (Dpp), and EGF receptor (Egfr) signaling pathways regulate embryonic DV patterning, as well as aspects of CNS patterning. Here we describe the earliest expression of each DV column gene (vnd, ind, and msh), the regulatory relationships between all three DV column genes, and the role of the Dorsal, Dpp, and Egfr signaling pathways in defining vnd, ind, and msh expression domains. We confirm that the vnd domain is established by Dorsal and maintained by Egfr, but unlike a previous report we show that vnd is not regulated by Dpp signaling. We show that ind expression requires both Dorsal and Egfr signaling for activation and positioning of its dorsal border, and that abnormally high Dpp can repress ind expression. Finally, we show that the msh domain is defined by repression: it occurs only where Dpp, Vnd, and Ind activity is low. We conclude that the initial diversification of cell fates along the DV axis of the CNS is coordinately established by Dorsal, Dpp, and Egfr signaling pathways. Understanding the mechanisms involved in patterning vnd, ind, and msh expression is important, because DV columnar homeobox gene expression in the neuroectoderm is an early, essential, and evolutionarily conserved step in generating neuronal diversity along the DV axis of the CNS.

Animals↗
PubMed1997

Regulation of lipid signaling pathways for cell survival and apoptosis by bcl-2 in prostate carcinoma cells.

Compelling evidence indicates that activation of the JNK/SAPK signaling pathway is obligatory for apoptosis induction by multiple cell stresses that activate the sphingomyelin cycle. Moreover, ectopic expression of bcl-2 can impair apoptosis signaling by most of the cell stresses that activate the ceramide/JNK pathway. Here we show that enforced expression of bcl-2 protects prostate carcinoma cells against the induction of apoptosis by exogenous C2-ceramide. Moreover, enforced bcl-2 expression blocked the capacity of C2-ceramide to activate JNK1, indicating bcl-2 functions at the level of JNK1 or upstream of JNK1 in the ceramide/JNK pathway. The contribution of bcl2 to the regulation of the arachidonate pathway for prostate carcinoma cell survival was also investigated using highly selective inhibitors of arachidonate metabolism. Our results indicate bcl-2 can protect cells against diminished availability of arachidonic acid, 12-HETE, and 15-HETE. Finally, arachidonic acid substantially suppresses the induction of apoptosis by C2-ceramide, providing evidence for the opposing influences of these lipid signaling pathways in the mediation of prostate carcinoma cell survival. These results provide evidence for opposing influences of the ceramide and arachidonate signaling pathways in the mediation of cell death and cell survival, respectively, in prostate carcinoma cells and suggest a dual role for bcl-2 in this context.

Animals↗