Figure 6.

Expression of RRM1, STIM1, and TRIM21 was associated with the level of acquired gemcitabine (GEM) resistance. A, Venn diagram showed the top 20 consistently upregulated mRNAs in both GEM‐resistant cell lines. B, Six intersected genes selected from among the top 20 consistently upregulated mRNAs. C and D, Total RNA and cytoplasmic proteins were extracted from BxPC‐3, BxPC‐3‐GR, CFPAC‐1, and CFPAC‐1‐GR. mRNA and protein expression levels of RRM1, STIM1, and TRIM21 were determined by quantitative reverse‐transcription polymerase chain reaction and western blot analysis. Glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) was used as a control. E and F, RRM1, STIM1, and TRIM21 protein expression levels were measured by western blot analysis in both parental cell lines and their derived GEM subclones. GAPDH was used as a control. G, RRM1, STIM1, and TRIM21 protein expression levels among normal pancreatic and pancreatic cancer (PC) cell lines were evaluated by western blot analysis. GAPDH was used as a control. H, Histogram shows IC₅₀ values for GEM in AsPC‐1, BxPC‐3, CFPAC‐1, MIA PaCa‐2, and PANC‐1 cell lines. **P < .01, ***P < .001; comparisons indicated by lines