Acquisition of GEM resistance in four other PDAC cell lines. Aspc1, Capan2, Panc1, and Panc2 human PDAC cell lines were continuously treated by GEM (0.1 nM) for 50 passages. (A) GEM sensitivity in four PDAC cell lines. Note, Panc1 and Panc2 cells acquired GEM resistance. (B,C) TFAM protein levels (B) and MYCC mRNA expression (C) were compared between parental cells and GEM-treated cells. Error bars represent standard error from three independent evaluations. * p < 0.05. PDAC—pancreatic ductal adenocarcinoma; GEM—gemcitabine; Aspc1-P—parental Aspc1; Aspc1-G—GEM-treated Aspc1; Capan2-P—parental Capan2; Capan2-G—GEM-treated Capan2; Panc1-P—parental Panc1; Panc1-G—GEM-treated Panc1; Panc2-P—parental Panc2; Panc2-G—GEM-treated Panc2; TFAM—mitochondrial transcription factor A.