Figure 1.

Cell morphology observed via light microscopy in HNSCC lines after incubation with palbociclib. 24 hours following plating, cells were incubated in 1μM palbociclib or left untreated (controls). Images were taken on day of drug addition (Day 0), as well as Day 3, and Day 5 of drug incubation. Representative images, at the same magnification throughout, at each time point are shown for both palbociclib treated and untreated control groups. Data presented for HPV- HNSCC lines (A) demonstrate flattening and enlargement, as well as decreased numbers, all characteristic features of senescence morphology, while HPV+ HNSCC lines appear similar to controls (B).