Figure 6. Ubenimex inhibits CD13 expression to modulate the EMP3/PI3K/AKT/NF-κB pathway in CDDP-resistant GC cells. (A, B) Co-IP assay using anti-Flag or anti-HA antibodies was performed in MKN-45/DDP (A) or Ubenimex-treated MKN-45/DDP cells (B). (C) Pull-down assay using anti-His, anti-Flag or anti-Myc antibodies was executed in HEK-293 cells that were transfected with the combination of p3×FLAG-CMV-14-EMP3, pET302 NT-His-CD13 and pCMV6-Myc-P85 plasmids. (D–F) MKN-45/DDP cells (D), BGC-823/DDP (E) and MGC-803/DDP (F) cells were treated with Ubenimex (0.2 or 0.4 mg/mL) for 24 h. Western blot assay was carried out to confirm the expression of the signaling molecules in the PI3K/AKT/NF-κB pathway. Data are represented as the representatives (upper panels), as well as the means±SD of relative intensities that were normalized to β-actin or corresponding total proteins (bottom panels) from three independent experiments *P<0.05, **P<0.01 and #P>0.05.