Expression of placental growth factor and vascular endothelial growth factor in ovarian teratomas of transgenic mice hypersecreting human chorionic gonadotropin

BETINA GONZALEZ; MATTI POUTANEN; ILPO HUHTANIEMI; RICARDO S. CALANDRA; SUSANA B. RULLI

Buenos Aires, Argentina

Jornada; VII Jornadas Multidisciplinarias de la Sociedad Argentina de Biología (SAB); 2005

Sociedad Argentina de Biología (SAB)

Human chorionic gonadotropin (hCG) is a glycoprotein honnone nonnally synthesized by the human placenta. It is structurally related to the luteinizing honnone, and acts through the same receptor. We have demonstrated that hCG overexpression induces the development of ovarian teratomas in transgenic mice (TG). These tumors are composed of disorganized tissues derived from embryonic and extraembryonic cells. Angiogenic factors are known to promote the fonnation of blood vessels, necessary to feed and maintain tumor growth. The placental growth factor (PIGF) is a member of the vascular endothelial growth factor (VEGF) family that has been shown to play an important role in promoting angiogenesis. Besides inducing its own signaling in endothelial cells, PIGF exerts its angiogenic action by synergising with VEGF. The objective of the present study was to analyze gene expression and immunolocalization ofVEGF and PIGF, by RT-PCR and immunohistochemistry in wild-type (wt) ovaries and TG ovarian tumors.The relative gene expressions of VEGF and PIGF were significantly increased in TG tumors compared with wt (p<0.05). Immunohistochemical analyses demonstrated that these factors were localized in the remnant ovarian tissue, and in the trophoblast giant cells present in the teratomas, which are typically found in the mouse placenta. In conclusion, the present results suggest that the trophoblast giant cells of the teratomas would contribute in promoting the angiogenic process in these tumors, through the expression of PIGF and VEGF.