Figure 1. Mutant KRAS is associated with PARPi, anti-PD-L1, and doublet combination therapy resistance in vivo.

(A and B) KRASWT(LPA1-T22)and KRASQ61H mutation (LPA1-T127) tumors were transplanted into the mammary fat pads of FVB mice. Eight days later, mice were randomized into treatment cohorts: vehicle (0.5% hydroxypropylmethylcellulose and 0.2% Tween 80), BMN673 (0.333 mg/kg per day), anti-PD-L1 antibody (200 μg/mouse every three days) or the combination of BMN673 and anti-PD-L1 (n=8 for each group). Tumor measurements were performed every 3 days by calipers, and average tumor volume ± SEM for each cohort is displayed. P values were determined by One-way analysis of variance test.
(C) PCA analysis was performed on each protein from RPPA data. Ellipses indicate 95% confidence interval of group membership. Axis percentages indicate variance contribution.
(D) Volcano plot shows differentially expressed proteins from RPPA data of LPA1-T22 and LPA1-T127. Proteins above the horizontal line and to the left and right of the vertical line exhibited over- (red circle) and under expression (green circle), respectively. Black circles represent non-differentially expressed proteins.
(E) Heatmap of RPPA data represents differentially expressed proteins (Log2 (Fold Change) ≥ 1, p<0.001). Different passages showed in X axis. Statistically significant changes (z- scores) indicated in boxes.
(F) Box plot of differentially expressed pMAPK, pMEK1 from RPPA data, Student’s t test.
(G) Murine MC38 colorectal cancer cells (5×105) were subcutaneously injected into the right flank of C57BL-6J mice (6–8 weeks old). When tumors were palpable, mice were randomized into treatment cohorts accordingly (n=8).
(H) Murine CT26 colorectal cancer cells (2×105) were subcutaneously injected into the right flank of Balb/C mice (6–8 weeks old). When tumors were palpable, mice were randomized into treatment cohorts accordingly (n=5).
In A-B, G and H data represent mean ± SEM.*p<0.05, **p<0.01, ***p<0.001, Non-parametric pairwise comparisons (Mann-Whitney).