Genetic variant in CASP3 affects promoter activity and risk of esophageal squamous cell carcinoma

Caspase-3 (CASP3) is the main executioner of apoptosis, mediating both extrinsic and intrinsic cell death signaling pathways, and is involved in tumor behaviors. In this study, we investigated the association of two regulatory variants in CASP3 and the risk of esophageal squamous cell carcinoma (ESCC) in 1026 cases and 1270 healthy controls. Odds ratios (OR) and 95% confidence intervals (CI) were computed by logistic regression. The function of the CASP3 829 A>C polymorphism was examined by luciferase reporter assay and real-time PCR. A significant increased risk of ESCC was found for the CASP3 829 AC and CC genotypes with OR (95% CI), 1.53 (1.26-1.89) and 1.42 (1.11-1.82), respectively. When stratified by age and gender, the risk of ESCC was more significant in younger (≤57 years) and male individuals. No significantly changed risk of ESCC was related to 20541 C>T variant. Luciferase reporter assay showed 829 A>C variant dramatically reduced the transcriptional activity of luciferase reporter gene by over 95% in both KYSE30 and KYSE450 esophageal cancer cells. Remarkably, the transcriptional activity of the 829C-containing construct was much lower than the activity of the pGL3-basic construct, with over 85% reduction in both cell lines. Real-time PCR analyses showed that 829 AA genotype carriers had significantly higher RNA levels (0.015 ± 0.00216, n = 24) than the 829 AC genotype carriers (0.00969 ± 0.00136, n = 36), and 829 CC genotype carriers (0.00663 ± 0.00097, n = 20). These findings suggest that CASP3 829 A>C polymorphism may highly affect the function of caspase-3 and play an important role in the development of ESCC in Chinese populations.