Extended Data Fig. 7: Modulation of AR activity is associated with differential response to BRAF/MEK inhibition.

A) Percent change in tumour volume in BP injected C57BL/6 female mice treated with vehicle in the presence or absence of BRAF/MEKi with endocrine modulation with either estradiol or estradiol and oophorectomy (n = 10/group; mice aged 14 weeks). No significant effects exist within either cohort as calculated by ANOVA. B) Percent change in tumour volume for female C57BL/6 mice implanted subcutaneously with YUMMER 1.7 cells treated with BRAF/MEKi or BRAF/MEKi + testosterone (n = 10/group; aged 13 weeks, p = 0.0003 between BRAF/MEKi and BRAF/MEKi + testosterone). C) Percent change in tumour volume in YUMMER1.7 injected into C57BL/6 male mice treated with vehicle in the presence or absence of BRAF/MEKi with endocrine modulation with enzalutamide (n = 10/group; mice aged 14 weeks, p = 0.031). D) Heatmap of differentially expressed androgen responsive genes between high versus low testosterone groups q < 0.05. Groups by androgen staining levels, sex, and treatment. E) Percent change in BP tumour volume in male C57BL/6 mice treated with vehicle in the presence or absence of BRAF/MEKi with physical castration or BRAF/MEKi with castration and exogenous testosterone (n = 10/group; aged 14 weeks, p = 0.01 for BRAF/MEKi + castration versus BRAF/MEKi, p = 0.04 for BRAF/MEKi versus BRAF/MEKi + castration + testosterone, and p = 0.0004 for BRAF/MEKi + castration vs BRAF/MEKi + castration + testosterone). F) Quantification of the percent of AR⁺ nuclei by immunofluorescence in BP tumours from male mice treated with vehicle (n = 7), BRAF/MEKi (n = 5), or BRAF/MEKi + enzalutamide (n = 7) (p = 0.003 between BRAF/MEKi and BRAF/MEKi + enzalutamide). p-values were calculated using two-sided Student’s t-test. G) Quantification of the percent of AR⁺ nuclei by immunofluorescence in BP tumours from female mice treated with vehicle (n = 7), BRAF/MEKi (n = 7), BRAF/MEKi + testosterone (n = 5) (p = 0.006 between vehicle and BRAF/MEKi and p = 0.003 between BRAF/MEKi and BRAF/MEKi + testosterone in female mice). p-values were calculated using two-sided Student’s t-test. Tumour growth curves in panels A-C and E represent mean + SEM. Histograms in panels F and G represent mean + SEM. All tumour growth curves were compared by ANOVA with multiple comparisons.