Effects of FRNK overexpression on Gem-induced chemoresistance in Panc-1 cells. A, The cell viability of parental Panc-1 cells and empty vector-transfected (Vector) and pcDNA3.1-FRNK plasmid-transfected (Pool 1) cells was determined by cell proliferation assays after treatment with or without 10 μM Gem for 24, 48 and 72 h. Results were expressed as the percentages of viable cells compared with parental cells without Gem treatment (left). The cell viability was statistically compared at 72 h after Gem treatment. Bars represent the mean of three independent experiments ± SE. *, P < 0.05, vs. parental cells without Gem treatment; #, P < 0.05, vs. parental or vector cells with Gem treatment (right). B, Parental Panc-1 cells and vector and pool 1 cells were treated with or without 10 _M Gem for 24 h. Cells were then trypsinized and seeded in equal numbers into 24-well plates for clonogenic assay. After14 to 18 days, the mean number of the colonies was counted (left). The inhibition rate was defined by comparison of the colony number of each group with that of parental cells without Gem treatment. Bars represent the mean of three independent experiments ± SE. *, P < 0.05, vs. parental cells without Gem treatment; #, P < 0.05, vs. parental or vector cells with Gem treatment (right).