Impact of CCN3 (NOV) glycosylation on migration/invasion properties and cell growth of the choriocarcinoma cell line Jeg3.

BACKGROUND Recently we have shown that the matricellular CCN3 protein expressed in invasive extravillous trophoblast cells (EVTs) is decreased in early-onset pre-eclampsia and is regulated by oxygen tension. Pathogenesis of pre-eclampsia relies on a shallow invasion of EVTs into the spiral arteries, which leads to hypoxia accompanied by uteroplacental insufficiency. Here we investigated the function of glycosylated and non-glycosylated CCN3 protein on cell growth as well as migration and invasion properties of the malignant trophoblast cell line Jeg3 which is a widely used model for the invasive trophoblast. METHODS AND RESULTS Stable transfection of Jeg3 choriocarcinoma cells with full length CCN3 resulted in high expression of secreted glycosylated and cellular non-glycosylated CCN3. These cells revealed significantly reduced growth in cell numbers combined with a significantly increased migratory and invasive capacity. Matrix metalloprotease (MMP)-2 and MMP-9 activities were enhanced dependent on CCN3 expression, which could be confirmed by CCN3 knockdown studies. Using recombinant glycosylated and non-glycosylated CCN3, we revealed that CCN3 decreased growth in Jeg3 cell numbers independent of its glycosylation status, whereas only non-glycosylated CCN3 was able to enhance migration and invasion properties. CONCLUSIONS The present results suggest that CCN3 protein regulates the decrease in Jeg3 cell numbers independent of its glycosylation status, whereas migratory and invasive properties are influenced only by non-glycosylated CCN3. An impaired balance in the expression of glycosylated and non-glycosylated CCN3 could contribute to the shallow invasion of EVTs observed in pre-eclampsia.