Department of Experimental Therapeutics and the Center for RNA Interference and Non-coding RNAs, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA.
Cancer Res. 2010 Apr 1;70(7):2789-98. doi: 10.1158/0008-5472.CAN-09-3541. Epub 2010 Mar 23.
Single-nucleotide polymorphisms (SNP) associated with polygenetic disorders, such as breast cancer (BC), can create, destroy, or modify microRNA (miRNA) binding sites; however, the extent to which SNPs interfere with miRNA gene regulation and affect cancer susceptibility remains largely unknown. We hypothesize that disruption of miRNA target binding by SNPs is a widespread mechanism relevant to cancer susceptibility. To test this, we analyzed SNPs known to be associated with BC risk, in silico and in vitro, for their ability to modify miRNA binding sites and miRNA gene regulation and referred to these as target SNPs. We identified rs1982073-TGFB1 and rs1799782-XRCC1 as target SNPs, whose alleles could modulate gene expression by differential interaction with miR-187 and miR-138, respectively. Genome-wide bioinformatics analysis predicted approximately 64% of transcribed SNPs as target SNPs that can modify (increase/decrease) the binding energy of putative miRNA::mRNA duplexes by >90%. To assess whether target SNPs are implicated in BC susceptibility, we conducted a case-control population study and observed that germline occurrence of rs799917-BRCA1 and rs334348-TGFR1 significantly varies among populations with different risks of developing BC. Luciferase activity of target SNPs, allelic variants, and protein levels in cancer cell lines with different genotypes showed differential regulation of target genes following overexpression of the two interacting miRNAs (miR-638 and miR-628-5p). Therefore, we propose that transcribed target SNPs alter miRNA gene regulation and, consequently, protein expression, contributing to the likelihood of cancer susceptibility, by a novel mechanism of subtle gene regulation.
单核苷酸多态性（SNP）与多基因疾病相关，如乳腺癌（BC），可以创建、破坏或修饰 microRNA（miRNA）结合位点；然而，SNP 干扰 miRNA 基因调控并影响癌症易感性的程度在很大程度上仍然未知。我们假设 SNP 对 miRNA 靶标结合的破坏是一种与癌症易感性相关的广泛机制。为了验证这一点，我们在计算机和体外分析了与 BC 风险相关的已知 SNP，以评估它们改变 miRNA 结合位点和 miRNA 基因调控的能力，并将这些 SNP 称为靶 SNP。我们确定了 rs1982073-TGFB1 和 rs1799782-XRCC1 作为靶 SNP，其等位基因可以通过与 miR-187 和 miR-138 的不同相互作用来调节基因表达。全基因组生物信息学分析预测大约 64%的转录 SNP 为靶 SNP，它们可以通过 >90%的结合能改变（增加/减少）潜在 miRNA::mRNA 双链体的结合能。为了评估靶 SNP 是否与 BC 易感性有关，我们进行了一项病例对照人群研究，观察到 rs799917-BRCA1 和 rs334348-TGFR1 的种系发生在具有不同 BC 发病风险的人群中存在显著差异。具有不同基因型的癌症细胞系中的靶 SNP、等位基因变异和蛋白质水平的荧光素酶活性显示，在两种相互作用的 miRNA（miR-638 和 miR-628-5p）过表达后，靶基因的表达受到差异调控。因此，我们提出转录靶 SNP 通过一种新的微妙基因调控机制改变 miRNA 基因调控，进而改变蛋白质表达，从而增加癌症易感性的可能性。
