Figure 5: CCS1477 decreases AR and AR-V7 signaling and inhibits growth in a 22Rv1 mouse xenograft model.

(a) Once 22Rv1 xenograft tumor volume reached 150mm³ then treatment commenced with either vehicle (measurements for n=9) or CCS1477 (measurements for n=4 per group), administered by oral gavage, at 10 or 20 mg/kg once daily (QD) or at 30 mg/kg every other day (QOD) for 28 days (vehicles collected at 26 days due to reaching a legal maximum). Mean tumor volume with standard error of mean is shown. p-values (*p=<0.05, **p=<0.01, ***p=<0.001) were calculated for vehicle compared to CCS1477 at 10mg/kg QD, 20 mg/kg QD, and 30 mg/kg QOD at 26 days using unpaired student t-test. (b) The effect of each condition on C-MYC, KLK3 and TMPRSS2 mRNA expression was determined for 7 days (left) and 28 days (26 days for vehicle) (right). Mean mRNA expression (normalized to an average of GAPDH/RPLP0 and vehicle treatment; defined as 1.0) with standard error of mean from individual tumors in each group (3 per group in 7 days, 5 per group from 28 days) are shown. p-values (*p=<0.05, **p=<0.01, ***p=<0.001) were calculated for each treatment condition compared to vehicle using unpaired student t-test. (c) The effect of each condition on AR-FL, AR-V7, C-MYC, and beta-actin protein expression was determined for 7 days (left) and 28 days (26 days for vehicle) (right). (d) Blood plasma KLK3 protein levels (ng/ml) were determined every 7 days by ELISA. Mean KLK3 protein levels with standard deviation from mice in each treatment group are shown. (e) Gene set enrichment analysis of RNA-sequencing for 26 days vehicle group and 28 days 20mg/kg CCS1477 QD group comparing the androgen response (left), AR signature (center) and AR-V7 signature (right) with normalized enrichment score (NES) and false discovery rate (FDR) are shown.