title: In vitro modeling of human pancreatic duct epithelial cell transformation defines gene expression changes induced by K-ras oncogenic activation in pancreatic carcinogenesis.
abstract: Genetic analysis of pancreatic ductal adenocarcinomas and their putative precursor lesions, pancreatic intraepithelial neoplasias (PanIN), has shown a multistep molecular paradigm for duct cell carcinogenesis. Mutational activation or inactivation of the K-ras, p16(INK4A), Smad4, and p53 genes occur at progressive and high frequencies in these lesions. Oncogenic activation of the K-ras gene occurs in >90% of pancreatic ductal carcinoma and is found early in the PanIN-carcinoma sequence, but its functional roles remain poorly understood. We show here that the expression of K-ras(G12V) oncogene in a near diploid HPV16-E6E7 gene immortalized human pancreatic duct epithelial cell line originally derived from normal pancreas induced the formation of carcinoma in 50% of severe combined immunodeficient mice implanted with these cells. A tumor cell line established from one of these tumors formed ductal cancer when implanted orthotopically. These cells also showed increased activation of the mitogen-activated protein kinase, AKT, and nuclear factor-kappaB pathways. Microarray expression profiling studies identified 584 genes whose expression seemed specifically up-regulated by the K-ras oncogene expression. Forty-two of these genes have been reported previously as differentially overexpressed in pancreatic cancer cell lines or primary tumors. Real-time PCR confirmed the overexpression of a large number of these genes. Immunohistochemistry done on tissue microarrays constructed from PanIN and pancreatic cancer samples showed laminin beta3 overexpression starting in high-grade PanINs and occurring in >90% of pancreatic ductal carcinoma. The in vitro modeling of human pancreatic duct epithelial cell transformation may provide mechanistic insights on gene expression changes that occur during multistage pancreatic duct cell carcinogenesis.
authors.affiliation: Ontario Cancer Institute/Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Jiaying
authors.initials: J
authors.lastname: Qian
authors.forename: Jiangong
authors.initials: J
authors.lastname: Niu
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Chiao
authors.forename: Ming-Sound
authors.initials: MS
authors.lastname: Tsao
mesh_terms: D021441:Carcinoma, Pancreatic Ductal / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000821:virology; D048708:Cell Growth Processes / Q000502:physiology; D002472:Cell Transformation, Viral / Q000235:genetics*; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology / Q000821:virology; D015972:Gene Expression Regulation, Neoplastic; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D007797:Laminin / Q000096:biosynthesis / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D009856:Oncogene Proteins, Viral / Q000502:physiology; D010183:Pancreatic Ducts / Q000166:cytology / Q000378:metabolism / Q000502:physiology* / Q000821:virology; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000821:virology; D027383:Papillomaviridae / Q000502:physiology; D050725:Papillomavirus E7 Proteins; D012097:Repressor Proteins / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D053773:Transforming Growth Factor beta1; D018631:ras Proteins / Q000096:biosynthesis / Q000235:genetics
chemical_list: C068651:E6 protein, Human papillomavirus type 16; D007797:Laminin; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012097:Repressor Proteins; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C059731:oncogene protein E7, Human papillomavirus type 16; D018631:ras Proteins