Curcumin enhances the effect of gefitinib against gefitinib-resistant relative proteins and by inducing apoptosis activity CL1-5 xenograft tumors.

(A) Western blotting analysis the gefitinib-resistant relative proteins EGFR, AKT, c-MET, cyclin D1, and PCNA showed the expression inhibition in curcumin alone or in combination group of xenograft tumor tissues. Western blotting results are represented with β-actin used as the internal control. Samples were pooled together from three animals in each group were analyzed and representative data are shown. (B) Western blotting analysis showing that combination of curcumin and gefitinib inhibits the expression of pro-caspase-8, pro-caspase-9 and pro-PARP and enhances the level of the cleavage (c)-PARP in xenograft tumor tissues. Western blotting results are represented with β-actin used as the internal control. Samples were pooled together from three animals in each group were analyzed and representative data are shown. (C) H&E staining, immunohistochemical staining of proliferation marker PCNA and apoptosis detection of TUNEL analysis in xenograft tumor sections from each group indicating that curcumin inhibited the tumor cell proliferation and enhanced the apoptotic cell death of gefitinib under a light microscope (×400 magnification).