Remote modulation of WWOX by an intronic variant associated with survival of Chinese gastric cancer patients.

The protein WWOX was reported to be involved in cancer progression via interaction with mTOR and DNA repair pathway. We previously reported noteworthy association of some single nucleotide polymorphisms (SNPs) in mTOR and DNA repair pathways with gastric cancer (GCa) patients' survival. We hypothesized that genetic variants in WWOX gene could predict the survival of GCa patients. By extracting WWOX genetic variants from our ongoing genome-wide association study including 796 GCa patients from an Eastern Chinese population, we identified 51 out of 1913 SNPs to be significantly associated with survival of GCa patients, which passed the false positive probability tests. In particular, the intronic variant rs9922483, a G>T change, was associated with 21% increased death risk for GCa patients (HR = 1.21, 95% CI = 1.04-1.42, P = .015). This locus was predicted to be involved in potential enhancer by bioinformatics analysis. Genotype-phenotype correlation analysis revealed decreased expression of WWOX by rs9922483 G>T change. Mechanistically, rs9922483 locus may exhibits long-range interaction with WWOX promoter, and the G>T change inhibited the transcriptional activity driven by WWOX promoter in luciferase reporter system. Especially, the G>T change had an allele-specific negative effect on NR3C1 binding, and NR3C1 promoted the expression of WWOX in GCa cells. Further functional analysis indicated an increase in proliferation, migration and invasion of GCa cells by knockdown of WWOX. In conclusion, WWOX genetic variants may modulate survival of Chinese GCa patients by exerting remote regulatory effect on WWOX expression. Our results highlight the cis-regulatory effect of genetic variants on genes and survival modulation for GCa patients.