scholarly journals Maximal epidermal growth-factor-induced cytosolic phospholipase A2 activation in vivo requires phosphorylation followed by an increased intracellular calcium concentration

1996 ◽  
Vol 313 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Casper G. SCHALKWIJK ◽  
Marcel A. G. van der HEIJDEN ◽  
Gertrude BUNT ◽  
Roel MAAS ◽  
Leon G. J. TERTOOLEN ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Map Kinase ◽  
Cell Lines ◽  
Cytosolic Phospholipase ◽  
Cpla2 Activation ◽  
Epidermal Growth

The 85 kDa cytosolic phospholipase A2 (cPLA2) preferentially catalyses the hydrolysis of arachidonic acid from the sn-2 position of phospholipids. cPLA2 can be activated by extracellular stimuli such as thrombin, platelet-derived growth factor and epidermal growth factor (EGF). A full activation of cPLA2 requires an increase of intracellular Ca2+ concentration and phosphorylation on Ser-505 by mitogen-activated protein (MAP) kinase. Because EGF can provoke an increase in intracellular [Ca2+] ([Ca2+]i) and activation of MAP kinase, we investigated the role of these pathways in EGF-induced activation of cPLA2. Characterization of two cell lines expressing different numbers of EGF receptors (HERc13 and HER14) revealed that both were activating MAP kinase in response to EGF, but only HER14 responded with an increase in [Ca2+]i. In this study we used both cell lines as a tool to clarify the role of each pathway in cPLA2 activation. We show that EGF stimulates cPLA2 activity in both cell lines in vitro as measured in cytosolic fractions, but only in HER14 in vivo as measured by 3H release from cells prelabelled with [3H]arachidonic acid. This latter activation can be restored in HERc13 cells by the addition of the ionophore A23187. Interestingly, this effect is only observed when EGF stimulation precedes A23187 addition. The phosphorylation of MAP kinase, however, was identical under identical conditions. We conclude that a maximal cPLA2 activation by EGF requires both, and in this order: MAP kinase activation followed by a rise in [Ca2+]i concentration.

scholarly journals LINC00037 Inhibits Proliferation of Renal Cell Carcinoma Cells in an Epidermal Growth Factor Receptor-Dependent Way

2018 ◽  
Vol 45 (2) ◽  
pp. 523-536 ◽  
Author(s):  
Xiaohui Gong ◽  
Xianjin Du ◽  
Yong Xu ◽  
Wenze Zheng
Keyword(s):  
Cell Cycle ◽  
Renal Cell Carcinoma ◽  
Cell Proliferation ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Epidermal Growth

Background/Aims: LINC00037 has previously been reported to be up-regulated in clear cell renal cell carcinoma (ccRCC), however, the underlying mechanism remained unknown. In this study, we designed to investigate the functional role of LINC00037 in ccRCC Methods: LINC00037 knockdown and re-expressing 786-O and A498 cells were established. CCK8 assay and EdU assay were performed to evaluate the proliferation rates of ccRCC cells. Flow cytometry assay was performed to detect the cell apoptosis and cell cycle. Subcutaneous injection xenotransplantation mouse model was used to observe the role of LINC00037 in tumor growth in vivo. Mass spectrometry (MS) was performed to find the interacting partner of LINC00037 and RNA immunoprecipitation (RIP) was carried out to validate their interaction. Results: We found that knockdown of LINC00037 resulted in inhibited cell proliferation with activated apoptosis and cell cycle arrest in vitro. Over-expression of LINC00037 in LINC00037 knockdown cells restored and enhanced cell proliferation. In vivo mouse model indicated reduced tumor progression by LINC00037 depletion and promoted tumor progression by LINC00037 overexpression. LINC00037 could bind to epidermal growth factor receptor (EGFR) and increase the protein level of EGFR. Conclusion: LINC00037 could inhibit proliferation of ccRCC in an epidermal growth factor receptor-dependent way.

scholarly journals 14-3-3 Facilitates Ras-Dependent Raf-1 Activation In Vitro and In Vivo

1998 ◽  
Vol 18 (7) ◽  
pp. 3947-3955 ◽  
Author(s):  
Sandrine Roy ◽  
Robert A. McPherson ◽  
Ann Apolloni ◽  
Jun Yan ◽  
Annette Lane ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Specific Activity ◽  
Membrane Recruitment ◽  
Oncogenic Ras ◽  
Epidermal Growth

ABSTRACT 14-3-3 proteins complex with many signaling molecules, including the Raf-1 kinase. However, the role of 14-3-3 in regulating Raf-1 activity is unclear. We show here that 14-3-3 is bound to Raf-1 in the cytosol but is totally displaced when Raf-1 is recruited to the plasma membrane by oncogenic mutant Ras, in vitro and in vivo. 14-3-3 is also displaced when Raf-1 is targeted to the plasma membrane. When serum-starved cells are stimulated with epidermal growth factor, some recruitment of 14-3-3 to the plasma membrane is evident, but 14-3-3 recruitment correlates with Raf-1 dissociation and inactivation, not with Raf-1 recruitment. In vivo, overexpression of 14-3-3 potentiates the specific activity of membrane-recruited Raf-1 without stably associating with the plasma membrane. In vitro, Raf-1 must be complexed with 14-3-3 for efficient recruitment and activation by oncogenic Ras. Recombinant 14-3-3 facilitates Raf-1 activation by membranes containing oncogenic Ras but reduces the amount of Raf-1 that associates with the membranes. These data demonstrate that the interaction of 14-3-3 with Raf-1 is permissive for recruitment and activation by Ras, that 14-3-3 is displaced upon membrane recruitment, and that 14-3-3 may recycle Raf-1 to the cytosol. A model that rationalizes many of the apparently discrepant observations on the role of 14-3-3 in Raf-1 activation is proposed.

Analysis of the role of p38 MAP kinase in epidermal growth factor-induced JB6 Cl41 cell transformation by cDNA array

Gene ◽  
2012 ◽  
Vol 497 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Zhiwei He ◽  
Ping Cui ◽  
Caiguo Ye ◽  
Wei-Ya Ma ◽  
Ann. Bode ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Map Kinase ◽  
Cell Transformation ◽  
Cdna Array ◽  
P38 Map Kinase ◽  
Epidermal Growth

scholarly journals Altered endocytosis of epidermal growth factor receptor in androgen receptor positive prostate cancer cell lines

2007 ◽  
Vol 38 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Lorella Bonaccorsi ◽  
Daniele Nosi ◽  
Monica Muratori ◽  
Lucia Formigli ◽  
Gianni Forti ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Androgen Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Lines ◽  
Growth Factor Receptor ◽  
Epidermal Growth

Although androgens and the androgen receptor (AR) are involved in tumorigenesis of prostate cancer (PC) in initial phases, less clear is the role played in advanced androgen-independent (AI) stages of the disease. Several recent reports indicated that re-expression of AR in PC-derived cell lines determines a less aggressive phenotype of the cells. We have previously demonstrated that re-expression of AR decreases the invasion ability of PC3 cells in vitro by affecting signalling and internalization processes of epidermal growth factor receptor (EGFR). Here, we show that reduced EGFR internalization is also a characteristic of AR positive PC cell lines LNCaP and 22Rv1. Reduced internalization in PC3-AR cells is associated to a defective interaction between the EGFR and two adaptor proteins which mediate the endocytotic process, Grb2 and c-Cbl. As a consequence of such reduced interaction, ubiquitination of the receptor, which is mainly mediated by c-Cbl, is also altered. In addition, we show that internalized EGFR co-localizes with early endosome antigen-1, a marker of clathrin-mediated endocytosis, in PC3-Neo cells but not in AR positive cell lines. Conversely, EGFR maintains co-localization with caveolin-1 after EGF stimulation in PC3-AR cells. These data suggest that expression of AR affects clathrin-mediated endocytosis pathway of EGFR, which, according to recent findings, plays an essential role in the completeness of signalling of the receptor. Taken together, these data emphasize the role of AR in the regulation of EGFR endocytotic trafficking and active signalling in PC cells. In view of the role of EGFR signalling in invasion of carcinoma cells, our data may explain the lower invasive phenotype observed in AR-positive cell lines.

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