NR4A2 and Patent ductus arteriosus: PDA is a prime example of a tumor that develops chemoresistance and to investigate the possible relationship between chemotherapeutic drugs and NURR1 expression pancreatic cancer cells were treated with gemcitabine and analysis by immunoblot and immunofluorescence showed that gemcitabine induced expression of NURR1 in both MiaPaCa2 and Panc1 cells (Fig. 1D and E).