Figure 6. Disruption of the Cyclin D-Cdk4,6-Rb Interaction Slows Tumor Growth.

(A) Schematic of mouse experiment. PiggyBac integration constructs containing doxycycline-inducible mouse Rb1 fused to fluorescent Clover and 3FLAG affinity tag sequences were transfected into Kras^+/G12D; Trp53^−/− mouse pancreatic ductal adenocarcinoma cells (CKP-2167). Approximately 1 million CKP-2167 cells expressing variants of doxycycline-inducible mouse Rb were allografted by subcutaneous implantation. After 5 days of engraftment and growth, mice were given water supplemented with doxycycline (2 mg/mL) for 2 weeks.

(B) Fold change in tumor volume compared to day 0 were calculated from caliper measurements. Data are mean ± SEM. A table of p values for all fold-change comparisons can be found in Figure S7B. n = 12 for empty, Rb^WT, Rb^{Helix mut.}, and Rb^ΔCdk.

(C) Median tumor weight and interquartile ranges 15 days after doxycycline induction of either empty vector, wild type Rb, or Rb^{Helix mut.} n.s., *p > 0.05, **p ≤ 0.05, and ***p ≤ 0.001. n = 4 for empty, n = 10 for Rb^WT, and n = 10 for Rb^{Helix mut.}