Protein kinase C alpha modulates growth and differentiation in Caco-2 cells.
OBJECTIVE
Caco-2 cells have been used extensively to elucidate events involved in intestinal cell proliferation and differentiation. Because individual isoforms of protein kinase C (PKC) and p21waf1, a cyclin-dependent kinase inhibitor, may regulate these processes, their role(s) on the growth and differentiation of Caco-2 cells were assessed.


METHODS
Protein abundance and subcellular distribution of several PKC isoforms, as well as the expression of p21waf1, were examined in preconfluent and postconfluent cells.


RESULTS
In cells at confluence (approximately 7 days postplating) and during their postconfluent phase (up to 20 days postplating), both total protein expression of PKC-alpha and its particulate distribution increased compared with their 3-day postplated counterparts. These findings were in agreement with those obtained by immunocytochemistry of PKC-alpha. In contrast, neither the total expression nor the subcellular distribution of PKC-betaI, -betaII, -delta, or -zeta changed significantly during these time periods. In addition, the expression of p21waf1, which can be induced by PKC-alpha, increased in postconfluent cells.


CONCLUSIONS
PKC-alpha, but not other isoforms of PKC, may modulate the proliferation and differentiation of Caco-2 cells. This regulation appears to be mediated, at least in part, via a mechanism involving p21waf1.
Abraham
C
C
Department of Medicine, University of Chicago, Illinois 60637, USA.
Scaglione-Sewell
B
B
Skarosi
S F
SF
Qin
W
W
Bissonnette
M
M
Brasitus
T A
TA
D018938:Caco-2 Cells; D002454:Cell Differentiation; D002455:Cell Division; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000032:analysis; D006801:Humans; D007422:Intestines / Q000166:cytology*; D007527:Isoenzymes / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology*
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D007527:Isoenzymes; D011493:Protein Kinase C