Evidence for a correlation between trophoblast invasiveness and STAT3 activity.
OBJECTIVE
Extravillous trophoblast cells are capable of invading decidual tissue during early pregnancy. This property is reminiscent of cancer cells. The invasiveness of trophoblasts, however, extends only to a well-regulated limit. Signal transduction processes underlying this phenomenon are as yet poorly characterized. Many factors involved in trophoblast invasiveness are known to trigger intracellular signaling cascades in other cell types that ultimately lead to the activation of signal transducers and activators of transcription (STATs). STAT3 activity was recently found related to the malignant phenotype of different tumor cells and potentially contributes to their invasive properties.


METHODS
We investigated the status of STAT3 activity in ex vivo trophoblast cells from first trimester and term placentae employing an electrophoretic mobility shift assay (EMSA) and compared it with that of a highly malignant choriocarcinoma cell line.


RESULTS
Specific DNA binding activity of two STAT3 variants (STAT3alpha and beta) was observed in immature trophoblasts and appeared to be lost in term placentae. The malignant phenotype of choriocarcinoma cells coincides with a high degree of STAT3 activity.


CONCLUSIONS
These results suggest a connection between STAT3 activity and trophoblast invasiveness.
Corvinus
Florian M
FM
Institute of Biochemistry, Friedrich-Schiller-University, Jena, Germany.
Fitzgerald
Justine S
JS
Friedrich
Karlheinz
K
Markert
Udo R
UR
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D045744:Cell Line, Tumor; D002822:Choriocarcinoma / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D009361:Neoplasm Invasiveness; D011247:Pregnancy; D050796:STAT3 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism*; D014327:Trophoblasts / Q000166:cytology / Q000502:physiology*; D014594:Uterine Neoplasms / Q000378:metabolism
D004268:DNA-Binding Proteins; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D015534:Trans-Activators; D004247:DNA