Kidney epithelial cells express c-sis protooncogene and secrete PDGF-like protein.
Nontransformed monkey kidney cells (BSC-1 line), used as a model for renal epithelium, were assayed for release of platelet-derived growth factor (PDGF)-like proteins. BSC-1 cells continuously released a mitogenic activity for fibroblasts and a chemoattractant activity for smooth muscle cells, each of which was inhibited 80-90% by an antibody to human PDGF. A cDNA probe for the PDGF B-chain gene (c-sis), but not for the A-chain gene, hybridized to mRNA obtained from growing and quiescent cells. c-sis gene expression and PDGF-like protein secretion were studied in the presence of known growth-regulatory molecules. A secreted BSC-1 cell protein identical to transforming growth factor beta 2 inhibited DNA synthesis in growing cultures and induced marked accumulation of c-sis mRNA without a corresponding increase in the release of PDGF-like activity. Adenosine diphosphate stimulated DNA synthesis in quiescent cultures and enhanced both c-sis expression and release of PDGF-like activity. However, growing and quiescent cells did not express the PDGF receptor gene or exhibit a mitogenic response to authentic PDGF. Thus the PDGF-like protein released by these kidney epithelial cells could contribute to growth control by a paracrine mechanism.
Kartha
S
S
Department of Medicine, University of Chicago, Illinois 60637.
Bradham
D M
DM
Grotendorst
G R
GR
Toback
F G
FG
D000818:Animals; D002460:Cell Line; D002633:Chemotaxis / Q000187:drug effects; D002522:Chlorocebus aethiops; D004261:DNA Replication; D004848:Epithelium / Q000378:metabolism; D005796:Genes; D007668:Kidney; D009130:Muscle, Smooth / Q000187:drug effects; D010982:Platelet-Derived Growth Factor / Q000235:genetics* / Q000494:pharmacology; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger