Angiotensin II does not stimulate proliferation of rat thyroid PC Cl3 cell line.
In PC Cl3 cells, a rat thyroid cell line, angiotensin (Ang II) activates the atypical protein kinase C-zeta (PKC-zeta) and the extracellular signal-regulated kinase (ERK) pathways. We here studied the Ang II effects on PC Cl3 cell proliferation. It was found that Ang II: (1) induced the phosphorylation of protein kinase B (PKB), (2) induced the growth-related early gene c-fos expression, (3) enhanced the cyclin E and p27(kip) expression, (4) had no effects on Cdk2, and (5) did not affect the transition from G0/G1 to S phase. Inhibition of phosphoinositide-3kinase by LY294002 further increased the effect of Ang II on p27(kip) induction, whilst PKCs inhibition by GF109203X decreased such effect. The role of PKC-zeta was recognized by the use of a synthetic myristoylated peptide with sequences based on the endogenous PKC-zeta pseudosubstrate and by PKC-zeta downregulation using the small interfering RNA (siRNA). Insulin had a replicating effect on PC Cl3 cells, induced the phosphorylation of PKB, decreased p27(kip) expression and had no effect on the PKC-zeta cytosol-to-membrane translocation. PC Cl3 cell proliferation was induced more potently by simultaneous stimulation with insulin and Ang II than by stimulation with insulin alone, and the effect on p27(kip) expression was similar to that obtained with insulin only. These observations demonstrate that in PC Cl3 cells Ang II causes a block in G1 phase, although both ERK and PKB pathways are activated, and this effect may be due to the upregulation of p27(kip) and PKC-zeta operativity.
Romano
Simona
S
Department of Biological and Environmental Sciences and Technologies, Ecotekne, Via Prov.le per Monteroni, 73100 Lecce, Italy.
Muscella
Antonella
A
Storelli
Carlo
C
Marsigliante
Santo
S
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D034622:RNA Interference; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects*; D013961:Thyroid Gland / Q000166:cytology* / Q000187:drug effects; D000099221:Protein Kinase C zeta
D000804:Angiotensin II; D002867:Chromones; D050760:Cyclin-Dependent Kinase Inhibitor p27; D048049:Extracellular Signal-Regulated MAP Kinases; D005419:Flavonoids; D007211:Indoles; D007328:Insulin; D008301:Maleimides; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D051057:Proto-Oncogene Proteins c-akt; D016760:Proto-Oncogene Proteins c-fos; D000099221:Protein Kinase C zeta; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C070515:bisindolylmaleimide I; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one