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Ras‐activators in trophoblastic cell lines
Author(s) -
Enkelmann A,
Poehlmann TG,
Roediger J,
Sedlmayr P,
Rubio I,
Markert UR
Publication year - 2006
Publication title -
american journal of reproductive immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.071
H-Index - 97
eISSN - 1600-0897
pISSN - 1046-7408
DOI - 10.1111/j.1600-0897.2006.00383_42.x
Subject(s) - mapk/erk pathway , epidermal growth factor , leukemia inhibitory factor , choriocarcinoma , microbiology and biotechnology , cell culture , biology , signal transduction , cytokine , chemistry , immunology , interleukin 6 , genetics
Background: Numerous cytokines influence functions and behaviour of trophoblast cells. The use of different signalling pathways is decisive for different functions, such as migration, proliferation and invasion. Epithelial growth factor (EGF), leukemia inhibitory factor (LIF) and interleukin‐6 (IL‐6) are major inducers. MAP Kinase (MAPK) pathways, which are related to invasiveness in many malignant cells, are expected to be involved. Material and Methods: The trophoblastic cell line AC1‐M59 and the choriocarcinoma cell line Jeg‐3 were stimulated with EGF, LIF or IL‐6. After 2–30 min, cells were lyzed and activated (GTP‐bound) ras was pulled down by using small modular GTPase‐binding domains derived from c‐Raf and sepharose micro‐beads. The ras‐containing pellet was analyzed by electrophoresis followed by Western blotting and detected with various anti‐ras antibodies. The remaining lysate was analyzed for phospho‐erk1/2. Results: In AC1‐M59 cells, EGF induced a strong and immediate ras and erk1/2 activation as visible at all analyzed time points. Effects of LIF were much lower and started 15 min after stimulation. IL‐6 did not induce detectable effects. Jeg‐3 cells displayed a high spontaneous ras activation which was not further increased after stimulation. Discussion: In trophoblastic cells, EGF activates signalling molecules of the MAPK pathways as similarly described for other cells. LIF is known to use the Jak/STAT pathway, which may be responsible for a slower ras activation than induced by EGF. The high spontaneous ras activation in Jeg‐3 cells may be related to their malign characteristics. Conclusion: EGF is a powerful activator of ras in trophoblastic cell lines, which may be a key signalling molecule for invasion of trophoblast cells.