UCSF

Microtubule targeting agents (MTAs) are anticancer therapies commonly prescribed for breast cancer and other solid tumors. Sensory peripheral neuropathy (PN) is the major dose-limiting toxicity for MTAs and can limit clinical efficacy. The current pharmacogenomic study aimed to identify genetic variations that explain patient susceptibility and drive mechanisms underlying development of MTA-induced PN. A meta-analysis of genomewide association studies (GWAS) from two clinical cohorts treated with MTAs (Cancer and Leukemia Group B (CALGB) 40502 and CALGB 40101) was conducted using a Cox regression model with cumulative dose to first instance of grade 2 or higher PN. Summary statistics from a GWAS of European subjects (n = 469) in CALGB 40502 that estimated cause-specific risk of PN were meta-analyzed with those from a previously published GWAS of European ancestry (n = 855) from CALGB 40101 that estimated the risk of PN. Novel single nucleotide polymorphisms in an enhancer region downstream of sphingosine-1-phosphate receptor 1 (S1PR1 encoding S1PR₁ ; e.g., rs74497159, β_{CALGB 40101} per allele log hazard ratio (95% confidence interval (CI)) = 0.591 (0.254-0.928), β_{CALGB 40502} per allele log hazard ratio (95% CI) = 0.693 (0.334-1.053); P_META  = 3.62 × 10^-7 ) were the most highly ranked associations based on P values with risk of developing grade 2 and higher PN. In silico functional analysis identified multiple regulatory elements and potential enhancer activity for S1PR1 within this genomic region. Inhibition of S1PR₁ function in induced pluripotent stem cell-derived human sensory neurons shows partial protection against paclitaxel-induced neurite damage. These pharmacogenetic findings further support ongoing clinical evaluations to target S1PR₁ as a therapeutic strategy for prevention and/or treatment of MTA-induced neuropathy.