Research Paper Volume 9, Issue 12 pp 2695—2716

Figure 4. Senescence features induced by ribociclib and palbociclib. (a) Cumulative bar chart showing the proportion of SW-13 and NCI-H295R treated cells in G1, S and G2/M cell cycle phases. (b) β-galactosidase activity is used as marker of senescence. The number of cells with β-galactosidase activity after treatment with ribociclib or palbociclib was counted and related to the number of cells with β−galactosidase activity after treatment with the vehicle only (DMSO or ethanol, respectively). Mean ratio and standard deviation were estimated from three independent experiments. (c) Flow cytometry analyses showing granularity of SW-13 and NCI-H295R cells treated with either palbociclib or ribociclib. Granularity is estimated by measuring the Side Scatter values (on the X-axis). (d) Flow cytometry analyses showing cell size of SW-13 and NCI-H295R treated with either palbociclib or ribociclib. Cell size is estimated by measuring the Side Scatter values (on the X-axis). (e) Colonies formed by SW-13 and NCI-H295R cells after coloring with crystal violet during the clonogenic assay. (f) The number of cell colonies formed after treatment with ribociclib or palbociclib was counted and related to the number of colonies formed after treatment with the vehicle only (DMSO or ethanol, respectively). The mean and standard deviation of percentage of colonies (compared to mock treatment) were estimated with three independent experiments. (g) Images in phase contrast showing the change of cell morphology of SW-13 and NCI-H295R cells upon treatment with either palbociclib or ribociclib. (h) Table summarizing the main aspects of senescence in both cell lines when treated with either palbociclib or ribociclib. For (b) and (f), *P<0.05, **P<0.01, ***P<0.001.