Overexpression and activation of the RON receptor tyrosine kinase in a panel of human colorectal carcinoma cell lines.
RON is a receptor tyrosine kinase belonging to the MET proto-oncogene family. The purposes of this study are to determine the expression and activation of RON in a panel of human colon carcinoma cell lines. Western blotting showed that RON is barely detectable in normal and SV-40-transformed colon epithelial cells, but highly expressed and constitutively activated in several colon carcinoma cell lines including Colo201, HT-29, HCT116, and SW837. Moreover, a novel RON variant with a molecular mass of 160 kDa (RONDelta160) was identified from HT-29 cells. The cDNA encoding RONDelta160 has an in-frame deletion of 109 amino acids in the extracellular domain of the RON beta chain, which is caused by splicing out of two exons in the RON mRNA. No mutations were found in the kinase domain of the RON gene in five carcinoma cell lines screened. By expressing RON in colon epithelial cells, we found that RON activation increases cell motile-invasive activities and protects cells against apoptotic death. These data suggest that RON expression and activation are deregulated in colon carcinoma cell lines. By abnormal activation of RON, this receptor and its variant may regulate motile-invasive phenotypes of certain colon carcinoma cells in vivo.
Chen
Y Q
YQ
Department of Medicine, University of Colorado School of Medicine and Denver Health Medical Center, Denver, Colorado 80204, USA.
Zhou
Y Q
YQ
Angeloni
D
D
Kurtz
A L
AL
Qiang
X Z
XZ
Wang
M H
MH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003106:Colon; D003110:Colonic Neoplasms / Q000201:enzymology*; D015179:Colorectal Neoplasms / Q000201:enzymology*; D004285:Dogs; D004789:Enzyme Activation; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology; D008969:Molecular Sequence Data; D000090063:Proto-Oncogene Mas; D020794:Receptor Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014407:Tumor Cells, Cultured
C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; C080835:RON protein; D020794:Receptor Protein-Tyrosine Kinases