Inhibition of phosphatidylinositol 3-kinase signaling negates the growth advantage imparted by a mutant epidermal growth factor receptor on human glioblastoma cells

2003 ◽  
Vol 105 (3) ◽  
pp. 331-339 ◽  
Author(s):  
Manuela Klingler-Hoffmann ◽  
Patricia Bukczynska ◽  
Tony Tiganis
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Kinase Signaling ◽  
Phosphatidylinositol 3 Kinase ◽  
Glioblastoma Cells ◽  
Human Glioblastoma ◽  
Epidermal Growth ◽  
Human Glioblastoma Cells

The role of the epidermal growth factor receptor in human gliomas: I. The control of cell growth

1995 ◽  
Vol 82 (5) ◽  
pp. 841-846 ◽  
Author(s):  
Hoi Sang U ◽  
Olivia D. Espiritu ◽  
Patricia Y. Kelley ◽  
Melville R. Klauber ◽  
James D. Hatton
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Retinoic Acid ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Soft Agar ◽  
Glioblastoma Cells ◽  
Human Glioblastoma ◽  
Anchorage Independent Growth ◽  
Epidermal Growth

✓ The epidermal growth factor receptor (EGFR) gene is amplified in over 40% of primary human glioblastomas and overexpressed in the majority. The authors' investigations demonstrate that the function of the EGFR in glioblastomas is distinct from that in other human cancers because it does not appear to mediate the primary growth-promoting effect of EGF. Findings show that the level of EGFR expression does not directly predict the growth response to EGF, with growth stimulated in some cells but inhibited in others when cells were cultured in plastic dishes. On the other hand, when human glioblastoma cells were placed in soft agar cultures, the cell line expressing the highest levels of the EGFR demonstrated considerable colony formation in response to EGF treatment. In addition, cell lines with the highest EGFR levels were also more resistant to the growth-suppressive effects of retinoic acid when maintained in soft agar. These observations suggest that even though the overexpression of the EGFR did not confer a distinct growth advantage to glioma cells cultured on flat culture dishes, the ability of these cells to maintain anchorage-independent growth in soft agar especially in response to EGF and retinoic acid is facilitated. Because anchorage-independent growth is the best in vitro correlate to tumorigenicity, amplification and overexpression of the EGFR in human glioblastoma cells may be in part responsible for the tumorigenic potential of these cells.

Epidermal growth factor receptor transactivation is required for proteinase-activated receptor-2-induced COX-2 expression in intestinal epithelial cells

2012 ◽  
Vol 303 (1) ◽  
pp. G111-G119 ◽  
Author(s):  
Christina L. Hirota ◽  
France Moreau ◽  
Vadim Iablokov ◽  
Michael Dicay ◽  
Bernard Renaux ◽  
...  
Keyword(s):  
Colon Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Intestinal Epithelial Cells ◽  
Growth Factor Receptor ◽  
Intestinal Epithelial ◽  
Kinase Signaling ◽  
Epidermal Growth ◽  
Cox 2

Proteinase-activated receptor (PAR)2, a G protein-coupled receptor activated by serine proteinases, has been implicated in both intestinal inflammation and epithelial proliferation. Cyclooxygenase (COX)-2 is overexpressed in the gut during inflammation as well as in colon cancer. We hypothesized that PAR2 drives COX-2 expression in intestinal epithelial cells. Treatment of Caco-2 colon cancer cells with the PAR2-activating peptide 2-furoyl-LIGRLO-NH2 (2fLI), but not by its reverse-sequence PAR2-inactive peptide, for 3 h led to an increase in intracellular COX-2 protein expression accompanied by a COX-2-dependent increase in prostaglandin E2 production. 2fLI treatment for 30 min significantly increased metalloproteinase activity in the culture supernatant. Increased epidermal growth factor receptor (EGFR) phosphorylation was observed in cell lysates following 40 min of treatment with 2fLI. The broad-spectrum metalloproteinase inhibitor marimastat inhibited both COX-2 expression and EGFR phosphorylation. The EGFR tyrosine kinase inhibitor PD153035 also abolished 2fLI-induced COX-2 expression. Although PAR2 activation increased ERK MAPK phosphorylation, neither ERK pathway inhibitors nor a p38 MAPK inhibitor affected 2fLI-induced COX-2 expression. However, inhibition of either Src tyrosine kinase signaling by PP2, Rho kinase signaling by Y27632, or phosphatidylinositol 3 (PI3) kinase signaling by LY294002 prevented 2fLI-induced COX-2 expression. Trypsin increased COX-2 expression through PAR2 in Caco-2 cells and in an EGFR-dependent manner in the noncancerous intestinal epithelial cell-6 cell line. In conclusion, PAR2 activation drives COX-2 expression in Caco-2 cells via metalloproteinase-dependent EGFR transactivation and activation of Src, Rho, and PI3 kinase signaling. Our findings provide a mechanism whereby PAR2 can participate in the progression from chronic inflammation to cancer in the intestine.

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