Carcinoma, Pancreatic Ductal/secondary; Gene Expression Regulation, Neoplastic/physiology; Liver Neoplasms/secondary; Osteonectin/genetics; Osteopontin/genetics; Pancreatic Neoplasms/pathology; Animals; Blotting, Western; Carcinoma, Pancreatic Ductal/genetics; Carcinoma, Pancreatic Ductal/metabolism; Cell Proliferation; Coculture Techniques; Disease Progression; Down-Regulation; Hepatocytes/metabolism; Hepatocytes/pathology; Humans; Liver Neoplasms/genetics; Liver Neoplasms/metabolism; Liver Neoplasms/prevention & control; Male; Oligonucleotides, Antisense/pharmacology; Pancreatic Neoplasms/genetics; Pancreatic Neoplasms/metabolism; RNA, Messenger/genetics; Rats; Rats, Nude; Recombinant Proteins; Reverse Transcriptase Polymerase Chain Reaction; Tumor Cells, Cultured