p21 and p27
mediated cytostatic effects upon activation of SSTR2/SSTR3. Cotransfected cells were treated with SST (1, 50 nM and 1 μM), L-779976 (10 and 100 nM) and L-796778 (25 and 50 nM) for 24 h with or without serum starvation and processed for p21 (top panel) and p27Kip1 (bottom panel) expression using Western blot analysis. Induction of p21 and p27Kip1 in response to SST and receptor-selective agonists suggests a cytostatic role for both receptors. The high basal levels of p21 observed in serum-deprived cells were maintained upon treatment with SST and specific agonists. Conversely, SST decreased p27Kip1 expression in cotransfected cells by ~50% in FBS-deficient conditions. β-Tubulin was used as a loading control. Results are expressed as mean ± S.D of three independent experiments.