Fig. 3.

Characterizing senescent cells. a, Representative images of CDKN1A (p21) and CDKN2A (p16) in A375 cells. Senescence was induced using doxorubicin (40 nM) for 4 days. The outline of the nucleus is indicated by the white line. Scale bar is 10 µm. b, Scatterplot of the p21 nuclear intensity vs. the p16 nuclear intensity of individual cells either mock-treated (dividing) or doxorubicin-treated (senescent) A375 cells. Red dots indicate cells that were treated with doxorubicin. Units of fluorescence intensity are arbitrary. c, Representative images of TP53 (p53) in A375 cells treated as described in a. d, Box and whisker plots of p21, p16, and p53 nuclear intensities in A375 cells treated as described in a. **** p-value < 0.0001. e, Bar graph of the percent of A375 cells positive for SA-β-gal. **** p-value < 0.0001. f, Scatterplot of the DNA content vs. the p21 nuclear intensity of individual A375 cells treated as in a. Color scale indicates the p16 nuclear intensity. Units of fluorescence intensity are arbitrary. The G2 phase cells are gated in blue. Percent positive for p21 and p16 is indicated for both dividing and senescent cells. See also Fig. S3.