title: Silencing of RON receptor signaling promotes apoptosis and gemcitabine sensitivity in pancreatic cancers.
abstract: The RON receptor tyrosine kinase is overexpressed in premalignant pancreatic intraepithelial neoplasia (PanIN) and in the majority of pancreatic cancers. In pancreatic cells, RON is an important K-Ras effector and RON ligand can enhance migration/invasion and apoptotic resistance. However, the pathobiological significance of RON overexpression in pancreatic cancers has yet to be fully established. In this study, we demonstrate that RON signaling mediates a unique transcriptional program that is conserved between cultured cells derived from murine PanIN or human pancreatic cancer cells grown as subcutaneous tumor xenografts. In both systems, RON signaling regulates expression of genes implicated in cancer-cell survival, including Bcl-2 and the transcription factors signal transducer and activator of transcription 3 (STAT 3) and c-Jun. shRNA-mediated silencing of RON in pancreatic cancer xenografts inhibited their growth, primarily by increasing susceptibility to apoptosis and by sensitizing them to gemcitabine treatment. Escape from RON silencing was associated with re-expression of RON and/or expression of phosphorylated forms of the related c-Met or epidermal growth factor receptors. These findings indicate that RON signaling mediates cell survival and in vivo resistance to gemcitabine in pancreatic cancer, and they reveal mechanisms through which pancreatic cancer cells may circumvent RON-directed therapies.
authors.affiliation: Department of Surgery, Division of Surgical Oncology, University of Cincinnati, Ohio, USA.
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Logan-Collins
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Thomas
authors.forename: Peter
authors.initials: P
authors.lastname: Yu
authors.forename: Dawn
authors.initials: D
authors.lastname: Jaquish
authors.forename: Evangeline
authors.initials: E
authors.lastname: Mose
authors.forename: Randall
authors.initials: R
authors.lastname: French
authors.forename: William
authors.initials: W
authors.lastname: Stuart
authors.forename: Rebecca
authors.initials: R
authors.lastname: McClaine
authors.forename: Bruce
authors.initials: B
authors.lastname: Aronow
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hoffman
authors.forename: Susan E
authors.initials: SE
authors.lastname: Waltz
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Lowy
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D016000:Cluster Analysis; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D020869:Gene Expression Profiling; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D008819:Mice, Nude; D020411:Oligonucleotide Array Sequence Analysis; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D034622:RNA Interference; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays; D000093542:Gemcitabine
chemical_list: D000964:Antimetabolites, Antineoplastic; D003841:Deoxycytidine; C080835:RON protein; D020794:Receptor Protein-Tyrosine Kinases; D000093542:Gemcitabine