Figure 5: In vivo function of P27.

(A) Mice bearing MCF7 xenografts were randomized for treatment with Vehicle (n=8) and palbociclib (n=6). Graph represents mean and SEM (2-way ANOVA). (B) Representative images of tumors that were excised from mice at the end of treatments. Column graph represents the relative tumor weight from the palbociclib treated group with mean and SEM (t test). (C) Tumors from the vehicle and palbociclib treated mice were stained for ki67. Representative images are shown (scale bar = 100 μm). (D) Representative images of multispectral staining on the tumor tissues from vehicle and palbociclib treated mice. P27 (cyan), pRB(S807/811) (pink) and pHH3 (S10) (green). Arrows indicate the pRB positive cells in the palbociclib treated tumor tissue and the corresponding P27 localization. Graphs represent the fraction of pRB and pHH3 positive cells from the vehicle (n=2) and palbociclib (n=2) treated mice. Mean and SD are shown (t-test). (E) The correlation between pRB positive cells and nuclear localization of P27 from the vehicle and palbociclib treated tumor at 3 different region of interest (ROI) were determined using Fisher exact test. (F) Graph represents the fraction of pRB positive cells that harbor nuclear localization of P27 from the vehicle and palbociclib treated groups. Mean and SD are shown (t-test). (G) Tumors excised from the mice bearing 3226 PDX, treated with vehicle and palbociclib in combination with trametinib (palbo/tram) were stained for ki67 and p27. Representative images are shown (scale bar = 100 μm). (H) Representative images of multispectral staining on the tumor tissues from vehicle and palbo/tram treated mice. pRB(S807/811) (pink) and pHH3 (S10) (green). Graphs represent the fraction of pRB and pHH3 positive cells from the vehicle and palbo/tram treated mice. Mean and SD are shown (t-test). (**p<0.01, ***p<0.001).