Antimetabolites, Antineoplastic/pharmacology; Carcinoma, Pancreatic Ductal/metabolism; Deoxycytidine/analogs & derivatives; Eukaryotic Initiation Factor-4E/metabolism; Intracellular Signaling Peptides and Proteins/metabolism; Pancreatic Neoplasms/metabolism; Protein Serine-Threonine Kinases/metabolism; Adult; Aged; Aged, 80 and over; Apoptosis; Carcinoma, Pancreatic Ductal/drug therapy; Carcinoma, Pancreatic Ductal/mortality; Cell Line, Tumor; Cell Survival/drug effects; Deoxycytidine/pharmacology; Drug Resistance, Neoplasm; Drug Synergism; Enzyme Inhibitors/pharmacology; Humans; Intracellular Signaling Peptides and Proteins/antagonists & inhibitors; Intracellular Signaling Peptides and Proteins/genetics; Isoenzymes/antagonists & inhibitors; Isoenzymes/genetics; Isoenzymes/metabolism; Kaplan-Meier Estimate; Middle Aged; Nuclear Proteins/metabolism; Pancreatic Neoplasms/drug therapy; Pancreatic Neoplasms/mortality; Phosphorylation; Protein Processing, Post-Translational; Protein Serine-Threonine Kinases/antagonists & inhibitors; Protein Serine-Threonine Kinases/genetics; RNA Splicing; RNA-Binding Proteins/metabolism; Serine-Arginine Splicing Factors; Signal Transduction; Gemcitabine