The Function of Oncogene B-Cell Lymphoma 6 in the Regulation of the Migration and Invasion of Trophoblastic Cells

Human placentation is a highly invasive process. Deficiency in the invasiveness of trophoblasts is associated with a spectrum of gestational diseases, such as preeclampsia (PE). The oncogene B-cell lymphoma 6 (BCL6) is involved in the migration and invasion of various malignant cells. Intriguingly, its expression is deregulated in preeclamptic placentas. We have reported that BCL6 is required for the proliferation, survival, fusion, and syncytialization of trophoblasts. In the present work, we show that the inhibition of BCL6, either by its gene silencing or by using specific small molecule inhibitors, impairs the migration and invasion of trophoblastic cells, by reducing cell adhesion and compromising the dynamics of the actin cytoskeleton. Moreover, the suppression of BCL6 weakens the signals of the phosphorylated focal adhesion kinase, Akt/protein kinase B, and extracellular regulated kinase 1/2, accompanied by more stationary, but less migratory, cells. Interestingly, transcriptomic analyses reveal that a small interfering RNA-induced reduction of BCL6 decreases the levels of numerous genes, such as p21 activated kinase 1, myosin light chain kinase, and gamma actin related to cell adhesion, actin dynamics, and cell migration. These data suggest BCL6 as a crucial player in the migration and invasion of trophoblasts in the early stages of placental development through the regulation of various genes associated with the migratory machinery.