Figure 4.

DDB1 increases the resistance of pancreatic xenograft tumors to GEM. (A) Stably transfected DDB1 shRNA or scrambled-shRNA PDAC cells were injected into nude mice, which were later divided into scramble, shDDB1, scramble+GEM and shDDB1+GEM groups and treated as described in the Methods. (B) The tumor sizes were measured by electronic Vernier calipers. Tumor growth curves were created based on the tumor volume. (C) The heatmap showed differentially expressed genes in shDDB1-transfected (D1) cells and scrambled-transfected (Sc) cells. (D) The expression of DDB1, dCK and Ki-67 was detected in tumor tissue slices from the xenografts using IHC (scale bar, 40 μm). (E) mRNA expression level of dCK in DDB1-silenced or scrambled PDAC cell lines. (F) Effect of DDB1 abrogation on the expression of dCK according to a Western blotting assay. Detailed information of Western blotting figures can be found at Supplement material Figure S1 and Table S3. (G) The correlation between DDB1 and dCK was determined by IHC scores. (H) The possible mechanism of DDB1-mediated GEM resistance and tumor progression due to dCK downregulation and changes in EMT-related genes in patients with PDAC. * p < 0.05, *** p < 0.001.