Figure 6. Senescence-dependent and -independent downregulation of p18^INK4c.

A. HDFs (Hs68) treated with the CDK4/6 inhibitor PD0332991 were harvested at the indicated intervals and levels of INK4c, B-MYB and CDC6 RNA were assessed by qRT-PCR and normalized to the untreated control. B. HDFs (TIG3) treated with and without PD0332991 for 14d were stained for SA-β-galactosidase activity and with DAPI to visualize SAHFs. C. Lysates from the cells described in panel B were immunoblotted for p18^INK4c, p16^INK4a, menin, and E2F1 with MEK as a loading control. D. HDFs (BF and Leiden) were infected with a retrovirus encoding H-RAS^G12V or empty vector and the relative levels of INK4c and INK4a RNA were assessed by qRT-PCR and normalized to the vector only control. E. Lysates from the cells described in panel D were immunoblotted for p18^INK4c and p16^INK4a. F. Lysates from Leiden cells infected with a retrovirus encoding H-RAS^G12V or empty vector were immunoblotted for menin, E2F1, p18^INK4c and RAS.