Figure 8.

Rendomab-B4 inhibits PLC but not ERK response due to ETB receptor activation in UACC. (A) [³H]inositol-labeled UACC-257 cells were treated or not for 2 h with 150 nM of control isotype antibody or Rendomab-B4 before stimulation for 30 min in the presence or the absence of 50 nM ET-1 or ET-3. Total [³H]InsPs amount was determined as described in materials and methods. Results are expressed as percent of InsPs production induced by ET-1 in the absence of antibody and are means ± SEM of 6 independent experiments, each performed in duplicate. (B) Cells were treated for 2 h with or without 150 nM of control isotype antibody or rendomab-B4 before the addition of 10 nM ET-1 or ET-3. After a 10 min incubation, cells were lysed and total proteins were analyzed by 10% SDS/PAGE followed by immunoblotting with anti-active phosphorylated ERK1/2 (pERK) antibody and anti-total ERK2 (ERK). pERK and ERK signals were quantified (C), and the levels of phosphorylated ERK1/2 were normalized with respect to total ERK2 amount in the corresponding sample. Results were expressed as percent of ET-1 stimulation without antibody treatment (100%). Values are the means ± SEM of 3 independent experiments performed in duplicate.