Overproduction of protein kinase C causes disordered growth control in rat fibroblasts.
We have generated a series of rat fibroblast cell lines that stably overexpress a full-length cDNA encoding the beta 1 form of protein kinase C (PKC). These cell lines contain a 20- to 53-fold increase in PKC activity and exhibit dramatically enhanced morphologic changes following exposure to the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA). They grow to a high saturation density in monolayer cultures and, when maintained at postconfluence, develop small, dense foci. In contrast to control cells, which display complete anchorage dependence, PKC-overproducing cells form small colonies in soft agar in the absence of TPA and large colonies in the presence of TPA. Thus, the mere overproduction of a single form of PKC is sufficient to confer multiple growth abnormalities in rat fibroblasts. These results provide direct evidence that PKC plays a critical role in growth control and that it mediates several of the cellular effects of the phorbol ester tumor promoters. They also suggest that the activation of PKC may be of central importance in the process of multistage carcinogenesis.
Housey
G M
GM
Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
Johnson
M D
MD
Hsiao
W L
WL
O'Brian
C A
CA
Murphy
J P
JP
Kirschmeier
P
P
Weinstein
I B
IB
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004247:DNA; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011493:Protein Kinase C / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D051381:Rats; D011955:Receptors, Drug; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D011955:Receptors, Drug; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D004247:DNA; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate