Induction of p21WAF1 expression and growth arrest in RH30 cells treated with TPA and U0126. (A) RH30 cells treated with 10 -7 M TPA (T) or 10 μM U0126 (U) for the times indicated. Whole cell lysates were analysed by immunoblotting with a specific antibody for p21WAF1, phosphorylated ERK1/2 and α-tubulin expression. (B) Growth graph of RH30 and RD cells after 4 days of TPA (T) or U0126 (U) treatments. (C) Immunoblot of total lysates using specific antibody capable of recognising the sarcomeric myosin heavy chain (MHC). Similar results were obtained in two experiments.