EFEMP1 binds the EGF receptor and activates MAPK and Akt pathways in pancreatic carcinoma cells.
The EGF-related protein EFEMP1 (EGF-containing fibulin-like extracellular matrix protein 1) has been shown to promote tumor growth in human adenocarcinoma. To understand the mechanism of this action, the signal transduction activated upon treatment with this protein has been investigated. We show that EFEMP1 binds EGF receptor (EGFR) in a competitive manner relative to epidermal growth factor (EGF), implicating that EFEMP1 and EGF share the same or adjacent binding sites on the EGFR. Treatment of pancreatic carcinoma cells with purified EFEMP1 activates autophosphorylation of EGFR at the positions Tyr-992 and Tyr-1068, but not at the position Tyr-1048. This signal is further transduced to phosphorylation of Akt at position Thr-308 and p44/p42 MAPK (mitogen-activated protein kinase) at positions Thr-202 and Tyr-204. These downstream phosphorylation events can be inhibited by treatment with the EGFR kinase inhibitor PD 153035. The observed signal transduction upon treatment with EFEMP1 can contribute to the enhancement of tumor growth shown in pancreatic carcinoma cells overexpressing EFEMP1.
Camaj
Peter
P
Department of Surgery, Munich University Medical Center, Campus Grosshadern, Marchioninistr. 15, D-81377 Munich, Germany.
Seeliger
Hendrik
H
Ischenko
Ivan
I
Krebs
Stefan
S
Blum
Helmut
H
De Toni
Enrico N
EN
Faktorova
Dagmar
D
Jauch
Karl-Walter
KW
Bruns
Christiane J
CJ
D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D010766:Phosphorylation; D010802:Phylogeny; D011485:Protein Binding; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology; D016415:Sequence Alignment
C119630:EFEMP1 protein, human; D016326:Extracellular Matrix Proteins; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; C512478:EGFR protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; C088860:4-((3-bromophenyl)amino)-6,7-dimethoxyquinazoline