Figure 5(A) MCF7 cells were incubated with serum-free CM collected from treated BJ fibroblasts (8 dpt) containing EdU for 45 hours and EdU+ cells quantified (n=9 samples from 3 independent experiments). Data information: Data are means ±SD. One-way ANOVA *p<0.05, **p<0.01, ***p<0.001, N.S.=not significant. CM, conditioned media. (B) MCF7 cells migrated through the pores of trans-well after 24 hours incubation with CM (8 dpt; scale bar, 1 mm; n=9 samples from 3 independent experiments) were stained with 0.2% crystal violet and quantified. Data information: Data are means ±SD. One-way ANOVA *p<0.05, **p<0.01, ***p<0.001, N.S.=not significant. CM, conditioned media. (C) Migration of A549 cells exposed to CM collected from treated BJ cells (8 dpt; n=4 independent samples, imaged together) was evaluated using a scratch assay. Imaging and analysis were done using a live imaging system. Data information: Data are means ±SD. Two-way ANOVA *p<0.05, **p<0.01, ***p<0.001, N.S.=not significant. CM, conditioned media. (D Treated BJ fibroblasts (2.5*105) were co-injected with A549 cancer cells (106) subcutaneously in Foxn1Nu mice, tumor growth was measured at the indicated times (n=6 mice/group) Data information: Data are means ±SD. Two-way ANOVA *p<0.05, **p<0.01, ***p<0.001, N.S.=not significant. PRO, proliferating cells. SEN, senescent cells. E) Treated BJ fibroblasts (2.5*105) were co-injected with A549 cancer cells (106) subcutaneously in Foxn1Nu mice excised tumors were weighed (E). Data information: Data are means ±SD. One-way ANOVA *p<0.05, **p<0.01, ***p<0.001, (F and G) p16-3MR mice were treated with vehicle (PBS, 7 consecutive days), doxorubicin (5 mg/kg, 3 consecutive days) or abemaciclib (50 mg/kg, 7 consecutive days). n=6 or 7 mice/group. At 14 dpt, MMTV-PyMT mouse breast cancer cells were implanted in the mammary fat pad of treated female mice. The tumors were excised and weighed 21 days post inoculation (left panel, images of the tumors; right panel, tumor weights) (F). The survival curves for different groups were plotted (G). Data information: Data are means ±SD. One-way ANOVA *p<0.05, **p<0.01, ***p<0.001, N.S.=not significant. (H and I) 2*105 cells of vehicle-treated (water for 8 times 24 hours) mouse dermal fibroblasts (MDF) were injected into the left flank of the p16-3MR mice. Doxorubicin-induced (250 nM for 24 hours) (H) or abemaciclib-induced (4 μM for 8 times 24 hours) (I) MDFs were injected into the right flank of the same animal. 7 dpt, the above-mentioned mice were injected with coelenterazine and bioluminescence from the p16-3MR mouse was visualized/quantified by the IVIS spectrum in vivo imaging system and quantified. Lower panel, scheme of experimental design (n=4 mice/group). Data information: Data are means ±SD. Paired student t-test *p<0.05, **p<0.01, ***p<0.001, N.S.=not significant. (J) Equal amount (2*105 cells) of doxorubicin-induced (250 nM for 24 hours, right flank) and abemaciclib-induced (4 μM for 8 times 24 hours, left flank) senescent MDF-3MR cells were subcutaneously injected into the same wild-type mice. At 1 dpt, 7 dpt and 15 dpt, the above-mentioned mice were injected with coelenterazine and bioluminescence from the injected MDF-3MR cells was visualized/quantified by the IVIS spectrum in vivo imaging system and quantified (n=4 mice/group). Upper panel, scheme of experimental design. Data information: Data are means ±SD. Two-way ANOVA *p<0.05, **p<0.01, ***p<0.001, N.S.=not significant.