Fig. 6. Coordinated targeting of COX2 with BRAF/MEK/EGFR improves efficacy in BRAFV600E CRC cell lines and PDXs.
a, Shift in vemurafenib sensitivity measured by cell viability assay (left) and calculation of CI (right) upon treatment of BRAFV600E CRC or melanoma cell lines with vemurafenib together with a COX2 inhibitor (celecoxib (CEL) or valdecoxib (VAL)) for 3 d. CI is averaged from experimentally measured CIs at 1×GI50, 2×GI50 and 0.5×GI50 concentrations of each drug (n ≥ 2 independent experiments). b, Treatment of BRAFV600E CRC or melanoma cell lines with up to four inhibitors, including trametinib, gefitinib and celecoxib at GI10. Cell growth inhibition across treatment permutations, normalized to vemurafenib monotherapy (left), was used to calculate CI relative to all other treatment arms and subjected to unsupervised hierarchical clustering comparing cell lines and treatment arms (right) (n = 24 independent experiments). c, Mouse weight as a surrogate for toxicity following treatment of BRAFV600E CRC PDXs (23 mice per treatment arm) with vehicle control, dabrafenib, trametinib, celecoxib and/or panitumumab (PAN). Data are displayed as the average weight in grams ± s.d. d, Tumor growth inhibition in BRAFV600E CRC PDX models following treatment with dabrafenib + trametinib ± celecoxib ± panitumumab or vehicle (control). Waterfall plots show the relative change in tumor volume: each bar represents one tumor, and the height of the bar compares the final volume at day 21 (D21) to the starting volume at day 1 (D1). Volume changes are capped at twofold the starting volume (that is, 200%). Tumors that regressed by day 21 are shown in red (compared to the volume at day 1) and purple (compared to the volume at mid-treatment, that is, day 10). Average final tumor volumes per treatment group are indicated underneath the graphs (black font). P values are indicated from two-sided Student’s t tests when P < 0.05. All raw and relative tumor volumes are available as Source Data. e, Semisupervised hierarchical clustering of the percentages of regressing tumors per treatment arm, comparing day 21 versus day 1 and day 21 versus day 10, from the data shown in d (that is, same number (n) of mice per treatment group and per PDX as in d). f, GLMs to test the association of change in tumor volume between treatment arms and vehicle over time. A GLM was applied to each PDX model, and all PDXs were combined. Left, effect size measured as the GLM standard coefficient; semi-unsupervised hierarchical clustering further compares the efficacy of the treatment arms. Right, ranking by GLM P values corrected for FDR. g, Comparison of effect size and FDR-corrected P values for treatment arms with and without the addition of celecoxib. Analyses in f,g used the same number (n) of mice per group as in d.