Truncated RON tyrosine kinase drives tumor cell progression and abrogates cell-cell adhesion through E-cadherin transcriptional repression.
RON is a tyrosine kinase receptor that triggers scattering of normal cells and invasive growth of cancer cells on ligand binding. We identified a short RON mRNA, which is expressed in human lung, ovary, tissues of the gastrointestinal tract, and also in several human cancers, including ovarian carcinomas and cell lines from pancreatic carcinomas and leukemias. This transcript encodes a truncated protein (short-form RON; sf-RON), lacking most of the RON receptor extracellular domain but retaining the whole transmembrane and intracellular domains. Sf-RON shows strong intrinsic tyrosine kinase activity and is constitutively phosphorylated. Epithelial cells transduced with sf-RON display an aggressive phenotype; they shift to a nonepithelial morphology, are unable to form aggregates, grow faster in monolayer cultures, show anchorage-independent growth, and become motile. We show that in these cells, E-cadherin expression is lost through a dominant transcriptional repression pathway likely mediated by the transcriptional factor SLUG. Altogether, these data show that expression of a naturally occurring, constitutively active truncated RON kinase results in loss of epithelial phenotype and aggressive behavior and, thus, it might contribute to tumor progression.
Laboratory of Cancer Genetics, Institute for Cancer Research and Treatment, University of Torino Medical School, 10060 Candiolo, Turin, Italy.
Chiara
C
Bardella
Barbara
B
Costa
Piera
P
Maggiora
Salvatore
S
Patane'
Martina
M
Olivero
Guglielmina N
GN
Ranzani
Michele
M
De Bortoli
Paolo M
PM
Comoglio
Maria Flavia
MF
Di Renzo
D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion; D002455:Cell Division; D002465:Cell Movement; D024202:Electrophoretic Mobility Shift Assay; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D000071250:Snail Family Transcription Factors; D013489:Suppression, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D015820:Cadherins; C000604407:SNAI1 protein, human; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D017228:Hepatocyte Growth Factor; D008156:Luciferases; C080835:RON protein; D020794:Receptor Protein-Tyrosine Kinases