Additive genotoxic effects in cord blood cells upon indirect exposure to chemotherapeutic compounds crossing an in vitro placental barrier

Prenatal exposure to toxins can adversely affect long-term health outcomes of the offspring. Though chemotherapeutics are now standard of care for treating cancer patients during pregnancy, certain compounds are known to cross the placenta and harm placental tissue. The consequences for the fetus are largely unexplored. Here we examined the responses of newborn cord blood mononuclear cells in tissue culture to two chemotherapeutic drugs, cyclophosphamide and epirubicin, when either directly exposed to these drugs, or indirectly after crossing a placenta trophoblast bilayer barrier. Cord blood mononuclear cells exposed to the conditioned media obtained from cyclophosphamide-exposed trophoblast barriers showed a significant 2.4-fold increase of nuclear ROS levels compared to direct exposure to cyclophosphamide. Indirect exposure to epirubicine-exposed trophoblast barriers not only enhanced nuclear ROS levels but also significantly increased the fraction of cord blood cells with double strand breaks, relative to directly exposed cells. Neither apoptosis nor proliferation markers were affected in cord mononuclear blood cells upon direct or indirect exposure to cyclophosphamide or epirubicin. Our data suggests that trophoblast cells exposed to cyclophosphamide or epirubicine may induce an indirect 'bystander' effect and can aggravate genotoxicity in the fetal compartment.