Department of Internal Medicine, Section of Gastroenterology, Rush University Medical Center, Chicago, Illinois, USA.
Alcohol Clin Exp Res. 2010 Jan;34(1):19-31. doi: 10.1111/j.1530-0277.2009.01061.x. Epub 2009 Oct 23.
Alcohol consumption is associated with the risk of progressive cancers including colon and breast cancer. The mechanisms for the alcohol-induced aggressive behavior of these epithelial cancer cells have not been fully identified. Epithelial-mesenchymal transition (EMT) is a developmental program recently shown to play a role in cancer progression and metastases. We hypothesized that alcohol might promote cancer progression by inducing EMT in cancer cells and tested this hypothesis by assessing alcohol-stimulated changes in phenotypic markers of EMT as well as the EMT transcription factor Snail and its related cell signaling.
Colon and breast cancer cell lines and a normal intestinal epithelial cell line were tested as well as colonic mucosal biopsy samples from alcoholic subjects. Cells were treated with alcohol and assessed for EMT-related changes using immunofluorescent microscopy, western blotting, reporter assays, RT-PCR, and knockdown of Snail with siRNA.
We show alcohol upregulated the signature EMT phenotypic marker vimentin as well as matrix metalloprotease (MMP)-2, MMP-7, and MMP-9 and cell migration in colon and breast cancer cells-all characteristics of EMT. Alcohol also stimulated nuclear localization of Snail phosphorylated at Ser246, transcription from a Snail reporter plasmid, and Snail mRNA expression by RT-PCR. Snail siRNA knockdown prevented alcohol-stimulated vimentin expression. In vivo, Snail expression was significantly elevated in colonic mucosal biopsies from alcoholics. Also, we found alcohol stimulated activation of epidermal growth factor receptor (EGFR) signaling and an EGFR inhibitor blocked alcohol-induced cell migration and Snail mRNA expression.
Collectively, our data support a novel mechanism for alcohol promoting cancer progression through stimulating the EMT program in cancer cells via an EGFR-Snail mediated pathway. This study reveals new pathways for alcohol-mediated promotion of cancer that could be targeted for therapy or prevention of alcohol-related cancers.
饮酒与结肠癌和乳腺癌等进展期癌症的风险相关。但导致这些上皮癌细胞中酒精诱导的侵袭性行为的机制尚未完全确定。上皮-间充质转化（EMT）是最近被证明在上皮性肿瘤进展和转移中起作用的一种发育程序。我们假设酒精可能通过诱导 EMT 来促进癌症进展，并通过评估 EMT 表型标志物、EMT 转录因子 Snail 及其相关细胞信号在酒精刺激下的变化，来验证这一假说。
我们检测了结肠和乳腺癌细胞系以及正常肠上皮细胞系，还检测了来自酒精性个体的结肠黏膜活检样本。用酒精处理细胞，并通过免疫荧光显微镜、Western blot、报告基因分析、RT-PCR 以及 Snail 的 siRNA 敲低来评估 EMT 相关变化。
我们发现酒精上调了 EMT 标志性表型标志物波形蛋白以及基质金属蛋白酶（MMP）-2、MMP-7 和 MMP-9，还刺激了结肠和乳腺癌细胞的迁移，这些都是 EMT 的特征。酒精还刺激了 Ser246 磷酸化的 Snail 的核定位、Snail 报告质粒的转录以及通过 RT-PCR 检测到的 Snail mRNA 表达。Snail 的 siRNA 敲低可防止酒精刺激的波形蛋白表达。在体内，酒精性个体的结肠黏膜活检样本中 Snail 的表达显著升高。此外，我们发现酒精刺激了表皮生长因子受体（EGFR）信号的激活，而 EGFR 抑制剂则阻断了酒精诱导的细胞迁移和 Snail mRNA 表达。
总之，我们的数据支持了一种新的机制，即酒精通过 EGFR-Snail 介导的途径刺激 EMT 程序促进癌细胞的癌症进展。本研究揭示了酒精介导的促进癌症的新途径，这些途径可能成为酒精相关性癌症治疗或预防的靶点。
