Department of Surgery, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
J Surg Res. 2011 Sep;170(1):56-63. doi: 10.1016/j.jss.2011.02.012. Epub 2011 Mar 23.
Epithelial-to-mesenchymal transition (EMT) is a series of molecular changes allowing epithelial cancer cells to acquire properties of mesenchymal cells: increased motility, invasion, and protection from apoptosis. Transcriptional regulators such as Slug mediate EMT, working in part to repress E-cadherin transcription. We report a novel, noninvasive in vivo rectal cancer model to explore the role of Slug in colorectal cancer (CRC) tumor development.
For the generation of DLD-1 cells overexpressing Slug (Slug DLD-1), a Slug or empty (Empty DLD-1) pCMV-3Tag-1 (kanamycin-resistant) vector was used for transfection. Cells were evaluated for Slug and E-cadherin expression, and cell migration and invasion. For the in vivo study, colon cancer cells (parental DLD-1, Slug DLD-1, empty DLD-1, and HCT-116) were submucosally injected into the posterior rectum of nude mice using endoscopic guidance. After 28 d, tumors were harvested and tissue was analyzed.
Slug expression in our panel of colon cancer cell lines was inversely correlated with E-cadherin expression and enhanced migration/invasion. Slug DLD-1 cells demonstrated a 21-fold increased Slug and 19-fold decreased E-cadherin expression compared with empty DLD-1. Similarly, the Slug DLD-1 cells had significantly enhanced cellular migration and invasion. In the orthotopic rectal cancer model, Slug DLD-1 cells formed rectal tumors in 9/10 (90%) of the mice (mean volume = 458 mm(3)) compared with only 1/10 (10%) with empty DLD-1 cells.
Slug mediates EMT with enhanced in vivo rectal tumor formation. Our noninvasive in vivo model enables researchers to explore the molecular consequences of altered genes in a clinically relevant rectal cancer in an effort to develop novel therapeutic approaches for patients with rectal cancer.
上皮-间质转化（EMT）是一系列分子变化，使上皮癌细胞获得间充质细胞的特性：增加运动性、侵袭性和抗凋亡能力。转录调节因子如 Slug 介导 EMT，部分通过抑制 E-钙黏蛋白转录起作用。我们报告了一种新的、非侵入性的直肠癌细胞体内模型，以探索 Slug 在结直肠癌（CRC）肿瘤发展中的作用。
为了生成过表达 Slug 的 DLD-1 细胞（Slug DLD-1），使用 Slug 或空（Empty DLD-1）pCMV-3Tag-1（卡那霉素抗性）载体进行转染。评估细胞中 Slug 和 E-钙黏蛋白的表达以及细胞迁移和侵袭。对于体内研究，使用内镜引导将结肠癌细胞（亲本 DLD-1、Slug DLD-1、Empty DLD-1 和 HCT-116）黏膜下注射到裸鼠的直肠后。28 天后，收获肿瘤并分析组织。
我们的结肠癌细胞系中 Slug 的表达与 E-钙黏蛋白的表达呈负相关，并增强了迁移/侵袭。Slug DLD-1 细胞与空 DLD-1 相比，Slug 表达增加了 21 倍，E-钙黏蛋白表达减少了 19 倍。同样，Slug DLD-1 细胞的细胞迁移和侵袭能力显著增强。在原位直肠癌细胞模型中，Slug DLD-1 细胞在 10 只（90%）小鼠中形成直肠肿瘤（平均体积=458mm3），而空 DLD-1 细胞只有 1 只（10%）。
Slug 通过增强体内直肠肿瘤的形成来介导 EMT。我们的非侵入性体内模型使研究人员能够在临床上相关的直肠癌细胞中探索改变基因的分子后果，以努力为直肠癌症患者开发新的治疗方法。
