Supplementary Figures and Tables Supplementary Table S1. Baseline Patient Demographic and Clinical Characteristics Supplementary Table S2. Observed and Expected Hardy Weinberg (HW) Frequency of SLCO Genotypes Supplementary Table S3. Distribution of Men with Undetectable Tissue ABI Levels Supplementary Table S4. Characteristics of SLCO Genotypes and Potential Prostate Cancer Associations Supplementary Table S5. Association of SLCO Genotype with Tissue Abiraterone, Estimated Tumor Volume and Minimal Residual Disease (MRD) Supplementary Figure S1. Representative chromatograms showing retention time for abiraterone standard and tissue samples. Supplementary Figure S2. Serum steroid levels in samples with undetectable vs detectable prostate abiraterone levels. Supplementary Figure S3. Association of SLCO single nucleotide polymorphisms with serum or tissue steroid levels. Supplementary Figure S4. Absolute abiraterone levels measured in LNCaP cells overexpressing SLCO2B1 or SLCO1B3.
Funding
DOD
NIH
Pacific Northwest
Dana-Farber Cancer Institute
Prostate Cancer Foundation
U.S. Department of Veterans Affairs
ARTICLE ABSTRACT
Purpose: Germline variation in solute carrier organic anion (SLCO) genes influences cellular steroid uptake and is associated with prostate cancer outcomes. We hypothesized that, due to its steroidal structure, the CYP17A inhibitor abiraterone may undergo transport by SLCO-encoded transporters and that SLCO gene variation may influence intracellular abiraterone levels and outcomes.Experimental Design: Steroid and abiraterone levels were measured in serum and tissue from 58 men with localized prostate cancer in a clinical trial of LHRH agonist plus abiraterone acetate plus prednisone for 24 weeks prior to prostatectomy. Germline DNA was genotyped for 13 SNPs in six SLCO genes.Results: Abiraterone levels spanned a broad range (serum median 28 ng/mL, 108 nmol/L; tissue median 77 ng/mL, 271 nmol/L) and were correlated (r = 0.355, P = 0.001). Levels correlated positively with steroids upstream of CYP17A (pregnenolone, progesterone), and inversely with steroids downstream of CYP17A (DHEA, AED, testosterone). Serum PSA and tumor volumes were higher in men with undetectable versus detectable tissue abiraterone at prostatectomy (median 0.10 vs. 0.03 ng/dL, P = 0.02; 1.28 vs. 0.44 cc, P = 0.09, respectively). SNPs in SLCO2B1 associated with significant differences in tissue abiraterone (rs1789693, P = 0.0008; rs12422149, P = 0.03) and higher rates of minimal residual disease (tumor volume < 0.5 cc; rs1789693, 67% vs. 27%, P = 0.009; rs1077858, 46% vs. 0%, P = 0.03). LNCaP cells expressing SLCO2B1 showed two- to fourfold higher abiraterone levels compared with vector controls (P < 0.05).Conclusions: Intraprostatic abiraterone levels and genetic variation in SLCO genes are associated with pathologic responses in high-risk localized prostate cancer. Variation in SLCO genes may serve as predictors of response to abiraterone treatment. Clin Cancer Res; 23(16); 4592–601. ©2017 AACR.