Adhesion of epithelial cells to fibronectin or collagen I induces alterations in gene expression via a protein kinase C-dependent mechanism.
Adhesion of human salivary gland (HSG) epithelial cells to fibronectin- or collagen I gel-coated substrates, mediated by beta1 integrins, has been shown to upregulate the expression of more than 30 genes within 3-6 h. Adhesion of HSG cells to fibronectin or collagen I for 6 h also enhanced total protein kinase C (PKC) activity by 1.8-2.3-fold. HSG cells expressed PKC-alpha, gamma, delta, epsilon, mu, and zeta. Adhesion of HSG cells to fibronectin or collagen I specifically activated PKC-gamma and PKC-delta. Cytoplasmic PKC-gamma and PKC-delta became membrane-associated, and immunoprecipitated PKC-gamma and PKC-delta kinase activities were enhanced 2.5-4.0-fold in HSG cells adherent to fibronectin or collagen I. In addition, adhesion of fibronectin-coated beads to HSG monolayers co-aggregated beta1 integrin and PKC-gamma and PKC-delta but not other PKC isoforms. Thus, integrin-dependent adhesion of HSG cells to fibronectin or collagen I activated PKC-gamma and PKC-delta. The role of this PKC upregulation on adhesion-responsive gene expression was then tested. HSG cells were treated with the specific PKC inhibitor bisindolylmaleimide I, cultured on non-precoated, fibronectin- or collagen I-coated substrates, and analyzed for changes in adhesion-responsive gene expression. Bisindolylmaleimide I strongly inhibited the expression of seven adhesion-responsive genes including calnexin, decorin, S-adenosylmethionine decarboxylase, steroid sulfatase, and 3 mitochondrial genes. However, the expression of two adhesion-responsive genes was not affected by bisindolylmaleimide I. Treatment with bisindolylmaleimide I did not affect cell spreading and did not significantly affect the actin cytoskeleton. These data suggest that adhesion of HSG cells to fibronectin or collagen I induces PKC activity and that this induction contributes to the upregulation of a variety of adhesion-responsive genes.
Lam
K
K
Northeastern Ontario Regional Cancer Centre, Sudbury, Ontario, Canada.
Zhang
L
L
Yamada
K M
KM
Lafrenie
R M
RM
D002448:Cell Adhesion; D002478:Cells, Cultured; D003094:Collagen / Q000494:pharmacology*; D003599:Cytoskeleton / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000378:metabolism* / Q000502:physiology* / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism; D005353:Fibronectins / Q000494:pharmacology*; D022001:Focal Adhesions / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D019012:Integrin beta1 / Q000502:physiology; D008301:Maleimides / Q000494:pharmacology; D020033:Protein Isoforms / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D015533:Transcriptional Activation; D015854:Up-Regulation
D004791:Enzyme Inhibitors; D005353:Fibronectins; D007211:Indoles; D019012:Integrin beta1; D008301:Maleimides; D020033:Protein Isoforms; D012333:RNA, Messenger; D003094:Collagen; D011493:Protein Kinase C; C070515:bisindolylmaleimide I