FIGURE 2.

IMP3 promotes chemoresistance by regulating BCRP. A, the immunoblot shows the restoration of IMP3 expression in IMP3-depleted cells (shIMP3-2) using a lentiviral expression construct that is resistant to shIMP3-2 (mut-IMP3). The chemoresistance of these cells was compared with either control cells (cells expressing shRNA targeting GFP) or IMP3-depleted cells infected with wild-type IMP3 expression construct, which can be targeted by shIMP3-2. shCtrl, short hairpin control. B, BCRP expression (protein and mRNA) was assessed by immunoblotting and real-time PCR in IMP3-depleted SUM-1315 and MDA-468 cells. C, IMP3-associated RNAs were isolated from the cytoplasmic extracts of SUM-1315 cells by immunoprecipitation using an IMP3 antibody (25 μg). Nonimmune mouse IgG was used as negative control. Expression of IGF2, ESR2, and BCRP was analyzed by real-time PCR. Error bars in all panels indicate S.D. *, p ≤ 0.05.