Our previous studies have shown that epithelial-mesenchymal transition (EMT) may be involved in the vasculogenic mimicry (VM) formation in hepatocellular carcinoma. Here, we hypothesize that zinc finger E-box binding homeobox 1 (ZEB1) promotes VM formation in colorectal carcinoma (CRC) by inducing EMT. We identified VM in 39 (19.2%) out of 203 CRC patients. The presence of VM was associated with aggressive biological behavior and was an unfavorable prognostic indicator. By immunohistochemical analysis, we found that the VM-positive CRC samples showed increased ZEB1 expression compared with the VM-negative samples and the ZEB1 expression occurred concomitantly with features of EMT. In vitro, knockdown of ZEB1 in poorly differentiated HCT116 CRC cells destroyed the vessel-like structures in the 3-D culture, a property associated with VM formation. Knockdown of ZEB1 resulted in restoration of epithelial phenotypes and significantly inhibited the ability to migrate and invade. In addition, ZEB1 underexpression decreased the expression of vascular endothelial (VE)-cadherin and Flk-1, which are characteristics of endothelial cells. Taken together, our results suggest that ZEB1 can promote VM formation by inducing EMT in CRC and might represent an important target in CRC. (Cancer Sci 2012; 103: 813-820)

This study aimed to determine the expression pattern of dickkopf-1 (Dkk1), a potent inhibitor of Wnt signaling, in colon cancer and to assess the function and mechanism of Dkk1 in tumor progression in vitro and in vivo. We detected the protein expression of Dkk1 and some epithelial-mesenchymal transition (EMT)-associated markers (E-cadherin, vimentin and β-catenin) in 217 tissue samples of human colon cancer, upregulated Dkk1 expression in HCT116 colon cancer cells, and established a nude mouse xenograft model. Dkk1 protein overexpression was inversely related to tumor grade and the presence of metastasis and recurrence of colon cancer. Notably, the expression of Dkk1 was concomitant with reduced immunohistochemical features of EMT (e.g. increased expression of epithelial marker E-cadherin, decreased expression of mesenchymal marker vimentin, and cytoplasmic distribution of β-catenin). Furthermore, Dkk1 overexpression resulted in restoration of the epithelial phenotype, decreased expression of EMT transcription factors Snail and Twist, and decreased expression of markers suggestive of intestinal stem cells (e.g. cluster of differentiation 133 [CD133] and leucine-rich-repeat-containing G-protein-coupled receptor 5 [Lgr5]). Functional analysis showed overexpression of Dkk1 reduced proliferation, migration, and invasion of colon cancer cells. Moreover, upregulation of Dkk1 led to decreased tumor-initiating ability and suppressed colon tumor growth in nude mice. Our findings indicate that Dkk1 can suppress the progression of colon cancer, possibly through EMT inhibition, and could therefore serve as a target for tumor therapy.

Purpose There is growing evidence implicating that neutrophil gelatinase–associated lipocalin (NGAL) plays a role in the development and progression of cancers. However, the effect of NGAL in colorectal carcinoma (CRC) has not been clearly elucidated. In this study, we investigated the role of NGAL in the tumorigenesis and progression of CRC and evaluated the clinical value of NGAL expression. Experimental Design We examined NGAL expression in 526 colorectal tissue samples, including 53 sets of matched specimens (histologically normal mucosa, adenomas, and carcinomas) using immunohistochemical analysis. In CRCs, correlations between NGAL expression and clinicopathologic parameters were analyzed, and survival analysis was conducted. The role of NGAL was further tested using mouse xenograft models. Results NGAL expression was elevated during the colorectal adenoma–carcinoma sequence both among the 526 cases (rs = 0.66, P < 0.001) and in the 53 sets of matched specimens (rs = 0.60, P < 0.001). In CRCs, NGAL expression was associated with cancer stage (P = 0.041) and tumor recurrence in stage II patients (P = 0.037). Survival analysis revealed that NGAL expression was an independent prognostic factor for overall survival (HR = 1.84, P = 0.004) and for disease-free survival of stage II patients (HR = 5.88, P = 0.021). In mouse models, the xenografts in cecum and spleen were heavier and more numerous in the group injected with NGAL-overexpressing CRC cells (P < 0.05). Conclusions NGAL overexpression may promote the tumorigenesis and progression of CRC. Detecting NGAL expression in tumor tissues may be useful for evaluating prognosis of patients with CRC.

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