Fig. 2

Treatment schedule affects induction of senescence by RT plus P. Human MCF7, MDA-MB-231 and mouse TS/A cells were cultured in control conditions or exposed to radiation therapy (RT), palbociclib (P) or their combination, followed by the assessment of cellular senescence upon colorimetric senescence-associated β-galactosidase (β-gal) assessment. Representative images taken 3 days from treatment initiation (a) and quantitative data (mean ± SEM plus individual data points) obtained 3 or 7 days after treatment initiation for MCF7 (b), MDA-MB-231 (c), and TS/A cells (d) are reported. Results are from 2–3 independent experiments each encompassing 3 technical replicates and 4 images per condition. Differences were evaluated for statistical significance by linear mixed-effects regression followed by simultaneous tests of general linear hypotheses; p values are reported. Percentage of β-gal⁺ cells is indicated in the upper left corner of each representative image. Scale bar: 50 µm