Functional implication of TRAIL −716 C/T promoter polymorphism on its in vitro and in vivo expression and the susceptibility to sporadic breast tumor
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Recently, TRAIL function has been elucidated beyond its known classical role of mediating cellular homeostasis and immune surveillance against transformed cells. Here, we show how CC genotype of −716 TRAIL promoter SNP rendered risk for sporadic breast cancer as compared to the CT and TT genotypes (P recessive model = 0.018, OR = 1.4, 95% CI = 1.1–1.9; P allele model = 0.010, OR = 1.3, 95% CI = 1.1–1.7). The in silico prediction of the introduction of core Sp1/Sp3-binding motif suggested the functional significance of the SNP variation. This functional implication was validated by luciferase assay in HeLa (P = 0.026), MCF-7 (P = 0.022), HepG2 (P = 0.024), and HT1080 (P = 0.030) cells and also by real-time expression studies on tumor tissues (P = 0.01), revealing the transcriptionally repressed status of −716 T when compared to −716 C allele. The SNP–SNP interactions reflected an enhanced protective effect of CT and TT genotypes with the protective genetic backgrounds of TP53-BRCA2 (P = 0.002, OR = 0.2, 95% CI = 0.1–0.6), IFNG (P = 0.0000002, OR = 0.3, 95% CI = 0.2–0.4), and common variant Casp8 (P = 0.0003, OR = 0.5, 95% CI = 0.3–0.7). Interestingly, a comparison with clinical parameters showed overrepresented CT and TT genotypes in progressing (P = 0.041) and ER/PR negative tumors (P = 0.024/0.006). This was explained by increased apoptotic index, calculated as a ratio of selected pro-apoptotic and anti-apoptotic gene expression profiles, in CC genotyped tumors, favoring either intrinsic (P = 0.008,0.018) or extrinsic (P = 0.025,0.217) pathway depending upon the ER/PR status. Our study reveals for the first time that a promoter SNP of TRAIL functionally modulates the gene and consequently its role in breast cancer pathogenesis, cautioning to consider the −716 TRAIL SNP status in patients undergoing TRAIL therapy.
KeywordsTRAIL Polymorphism Apoptosis
The authors would like to thank the patient and control subjects for their participation. RP is grateful to the Council of Scientific and Industrial Research, New Delhi, India, for the pre-doctoral fellowship. RB was supported by a research grant from the University Grants Commission to the National Centre of Applied Human Genetics and the University with Potential of Excellence projects.
- 10.Giovarelli M, Musiani P, Garotta G, Ebner R, Di Carlo E, Kim Y, Cappello P, Rigamonti L, Bernabei P, Novelli F, Modesti A, Coletti A, Ferrie AK, Lollini PL, Ruben S, Salcedo T, Forni G (1999) A “stealth effect”: adenocarcinoma cells engineered to express TRAIL elude tumor-specific and allogeneic T cell reactions. J Immunol 163(9):4886–4893PubMedGoogle Scholar
- 21.Herzer K, Grosse-Wilde A, Krammer PH, Galle PR, Kanzler S (2008) Transforming growth factor-beta-mediated tumor necrosis factor-related apoptosis-inducing ligand expression and apoptosis in hepatoma cells requires functional cooperation between Smad proteins and activator protein-1. Mol Cancer Res 6(7):1169–1177PubMedCrossRefGoogle Scholar
- 27.Weber A, Wandinger KP, Mueller W, Aktas O, Wengert O, Grundstrom E, Ehrlich S, Windemuth C, Kuhlmann T, Wienker T, Bruck W, Zipp F (2004) Identification and functional characterization of a highly polymorphic region in the human TRAIL promoter in multiple sclerosis. J Neuroimmunol 149(1–2):195–201PubMedCrossRefGoogle Scholar
- 30.Unoki M, Furuta S, Onouchi Y, Watanabe O, Doi S, Fujiwara H, Miyatake A, Fujita K, Tamari M, Nakamura Y (2000) Association studies of 33 single nucleotide polymorphisms (SNPs) in 29 candidate genes for bronchial asthma: positive association a T924C polymorphism in the thromboxane A2 receptor gene. Hum Genet 106(4):440–446PubMedCrossRefGoogle Scholar
- 31.Gochhait S, Bukhari SI, Bairwa N, Vadhera S, Darvishi K, Raish M, Gupta P, Husain SA, Bamezai RN (2007) Implication of BRCA2–26 > A 5′ untranslated region polymorphism in susceptibility to sporadic breast cancer and its modulation by p53 codon 72 Arg > Pro polymorphism. Breast Cancer Res 9(5):R71PubMedCrossRefGoogle Scholar
- 34.Vandesompele J, De Preter K, Pattyn F, Poppe B, Van Roy N, De Paepe A, Speleman F (2002) Accurate normalization of real-time quantitative RT-PCR data by geometric averaging of multiple internal control genes. Genome Biol 3 (7):RESEARCH0034Google Scholar