Heparin down‐regulates the phorbol ester‐induced protein kinase C gene expression in human endothelial cells: enzyme‐mediated autoregulation of protein kinase C‐α and ‐δ genes¹

Abstract

Overexpression of protein kinase C-K K and protein kinase C-N N has been shown to modulate a number of biological effects, including the cell growth and differentiation. We hypothesized that heparin, a potent antimitogenic drug, could affect the cell proliferation by inhibiting the expression of specific protein kinase C genes. Heparin, markedly but not completely, inhibited the serum-stimulated protein kinase C-K K and -N N mRNA expression. Protein kinase C inhibition or downregulation significantly decreased the serum-induced protein kinase C isoenzyme gene expression. Heparin failed to inhibit the residual effect of serum that was resistant to the abovementioned treatments. Phorbol 12-myristate 13-acetate elicited an increase of protein kinase C isoenzyme gene expression that was completely prevented by protein kinase C inhibition or downregulation. Heparin dose-dependently counteracted and ultimately abolished the increase in the protein kinase C isoenzyme gene expression elicited by phorbol 12-myristate 13-acetate. These results suggest that the inhibition of an autoregulatory role wielded by protein kinase C on the protein kinase C-K K and -N N gene expression might represent a possible mechanism by which glycosaminoglycans modulate the cell growth.z 1999 Federation of European Biochemical Societies.

Membrane Structure Modulation, Protein Kinase Cα Activation, and Anticancer Activity of Minerval

“…In this context, PKC down-regulation induced by phorbol esters is caused by proteolytic degradation of the strikingly activated enzyme (Junoy et al, 2002). In turn, moderate PKC activation would result in elevated protein levels (Pintus et al, 1999), which are not masked by proteolysis.…”

Inhibition of the MEK/ERK signaling pathway by the novel antimetastatic agent NAMI‐A down regulates c‐mycgene expression and endothelial cell proliferation

“…Serum‐starved or growing ECV304 cells cultured in T25 culture flasks (Falcon, Oxnard, CA, USA), were treated as described in figure legends. At the indicated time points, total RNA was extracted, reverse transcribed and amplified according to a previously described procedure [19]. Total RNA (1 µg) from ECV304 cells was reverse‐transcribed for 45 min at 37 °C.…”

“…Using 30 PCR cycles, the products of glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and c‐ myc amplification were all within the linear phase of the reaction. Indeed, similar conditions have been previously reported for semiquantitative analysis of gene expression [19]. The position of PCR fragments was evaluated by comparison with a DNA molecular mass marker (Gibco BRL).…”

Serum protein kinase Cα as a diagnostic biomarker of cancers

“…This difference may be caused by the inhibition of PKCα activation by heparin. Several studies reported that heparin suppresses the activity of PKCα when it is added into not only cells but also cell extracts [14][15][16]. 2.…”