Figure 3. MEK inhibition causes loss of D-cyclin expression, RB hypophosphorylation and G1 arrest in BRAF mutant cancer cells.
a, Immunoblot showing the kinetics of change in p-ERK, D-cyclin expression and RB in SKMEL28 cells treated with 1 µM CI-1040. b, CI-1040 induced a G1 growth arrest in BRAF mutant tumour cells but not in RAS/BRAF-WT breast cancer cells (BT-474 shown). c, d, CI-1040 induces apoptosis in some but not all cancer cell lines with the BRAF(V600E) mutation as measured by FACS analysis (c) and PARP cleavage (d).