Slug, a member of the Snail family of transcription factors, has a crucial role in the regulation of epithelial-mesenchymal transition (EMT) by suppressing several epithelial markers and adhesion molecules, including E-cadherin. A recent study demonstrated that no relationship exists between Slug and E-cadherin in pancreatic cancer. Another study showed that in malignant mesothelioma effusions Slug was associated with matrix metalloproteinase (MMP) expression, but that there was no association with E-cadherin. F-ascin is an actin-bundling protein involved in filopodia assembly and cancer invasion and metastasis of multiple epithelial cancer types. In this study, we investigated Slug, E-cadherin, and MMP-9 expression using immunohistochemistry in 60 patients with pancreatic cancer and their correlation with carcinoma invasion and metastasis. Additionally, we observed the effects of Slug on invasion and metastasis in the pancreatic cancer cell line PANC-1. Alterations in Slug, MMP-9, and E-cadherin were determined by RT-PCR, western blot, and immunohistochemistry. Alterations in MMP-9 and F-actin cytoskeleton were determined by immunofluorescence staining, flow cytometry (FCM), or gelatin zymography. Slug, E-cadherin, and MMP-9 expression in pancreatic cancer was significantly associated with lymph node metastases and we found a significant correlation between Slug and MMP-9 expression; however, no significant correlation was observed between Slug and E-cadherin expression. Slug transfection significantly increased invasion and metastasis in PANC-1 cells and orthotopic tumor of mouse in vivo, and significantly upregulated and activated MMP-9; however, there was no effect on E-cadherin expression. Slug promoted the formation of lamelliopodia or filopodia in PANC-1 cells. The intracellular F-actin and MMP-9 was increased and relocated to the front of the extending pseudopodia from the perinuclear pool in Slug-transfected PANC-1 cells. These results suggest that Slug promotes migration and invasion of PANC-1 cells, which may correlate with the reorganization of MMP-9 and remodeling of the F-actin cytoskeleton, but not with E-cadherin expression.

Colorectal cancer (CRC) is the third most frequently diagnosed cancer and the third leading cause of cancer death in the Western world. Chemotherapy has been shown to improve outcomes in patients with CRC; however, only selected patients would benefit from this treatment. We aimed to identify predictors of response to chemotherapy in CRC using circulating microRNAs (miRNAs). We studied differential miRNA expression by miRNA array from serum of 253 patients who had chemotherapy treatment. We screened the differentially expressed serum miRNAs with TaqMan low-density arrays using pooled CRC patient serum samples. Differential expression was validated using hydrolysis probe-based stem-loop quantitative reverse transcription PCR in individual samples. We performed additional unsupervised cluster to analyse the differential expression of serum miRNA between the chemosensitive and chemoresistant patients. A distinct miRNA expression signature in response to chemotherapy was identified. The TaqMan low-density array results demonstrated that 17 serum miRNAs could predict chemosensitivity and chemoresistance. The quantitative reverse transcription PCR analysis further identified a profile of five serum miRNAs (miR-20a, miR-130, miR-145, miR-216 and miR-372) as a biomarker for predicting the chemosensitivity of CRC. The areas under the receiver operating characteristic curve of this five-serum miRNA signature were 0.841 and 0.918 for the two sets of serum samples, respectively. We identified a group of miRNA predictors in response to chemosensitivity for CRC patients. This could lead to a significant improvement in chemotherapy regimen selection strategy and personalized CRC management.

ERK1/2 activity may protect pancreatic cancer cells from chemotherapy-induced apoptosis. The combined use of an ERK1/2 inhibitor (such as U0126) together with gemcitabine may result in synergistic therapeutic effects at tolerable gemcitabine doses.

ObjectivesThis study explored the expression and function of Slug in human extrahepatic hilar cholangiocarcinoma (EHC) to identify its role in tumor progression.MethodsThe expression of Snail and Slug mRNA in 52 human tissue samples of EHC was investigated. The mRNA of Snail and Slug were quantified using reverse transcriptase-PCR, and correlations with E-cadherin expression and clinicopathological factors were investigated. We then investigated transfection of Slug cDNA in endogenous E-cadherin-positive human EHC FRH0201 cells, selectively induced the loss of E-cadherin protein expression, and then small interfering RNA (siRNA) for inhibition of Slug expression in endogenous Slug-positive human EHC QBC939 cells, selectively induced the loss of Slug protein expression. A Boyden chamber transwell assay was used for invasion.ResultsSlug mRNA was overexpressed in 18 cases (34.6%) of EHC compared with adjacent noncancerous tissue. E-Cadherin protein expression determined in the same 52 cases by immunohistochemistry was significantly down-regulated in those cases with Slug mRNA overexpression (P = 0.0001). The tumor and nontumor ratio of Slug mRNA was correlated with nodal metastasis(p = 0.0102), distant metastasis (p = 0.0001)and Survival time(p = 0.0443). However, Snail mRNA correlated with neither E-cadherin expression nor tumor invasiveness. By inhibiting Slug expression by RNA interference, we found that reduced Slug levels upregulated E-cadherin and decreased invasion in QBC939 cell. When the QBC939 cells was infected with Slug cDNA,, significant E-cadherin was downregulated and increased invasion in QBC939 cell.ConclusionsThe results suggested that Slug expression plays an important role in both the regulation of E-cadherin expression and in the acquisition of invasive potential in human EHC. Slug is possibly a potential target for an antitumor therapy blocking the functions of invasion and metastasis in human EHCs.

Slug is a transcription factor and E-cadherin repressor, which has recently been demonstrated to be important for cancer cells to down-regulate epithelial markers and up-regulate mesenchymal markers in order to become motile and invasive. In the present study, we assessed the relevance of Slug for invasion and growth potential of esophageal adenocarcinoma (EA) cells in vitro and in vivo. Slug expression was detected in nine human esophageal cancer cell lines. OE33 cell line was infected with Slug siRNA to knockdown of Slug; TE7 cell line was infected with full Slug cDNA to increase Slug expression. Then, Bcl-2 and E-cadherin expression and Caspase-3 activity were analyzed. MTT assay was applied to detect growth curve. The flow cytometric and Hoechst33258 staining was performed to detect apoptosis. The cells invasion in vitro was detected with a Boyden chamber. A pseudometastatic model of OE33 and TE7 in immunodeficient mice was used to assess the effects of knockdown of Slug and Slug overexpression on metastasis development. A subcutaneously nude mice xenograft model of OE33 and TE7 was used to assess the effects of knockdown of Slug and Slug overexpression on tumor growth. Immunohistochemical staining was used to analyze the expression of Slug, bcl-2 and E-cadherin, and TUNEL was used to detected apoptosis in vivo. Western blotting and RT-PCR showed that Slug expression was detectable in 7 of 9 human esophageal cancer cell lines. Bcl-2 was down-regulated and E-cadherin was up-regulated significantly in Slug siRNA-infected OE33 cell line (P<0.01). Bcl-2 was upregulated and E-cadherin was downregulated significantly in Slug cDNA-infected TE7 cells (P<0.05). OE33 cells with Slug knockdown were shown to possess markedly decreased invasiveness (P<0.05) and markedly increased apoptosis (P<0.05). Slug cDNA-infected TE7 cells were shown only to possess markedly increased invasiveness (P<0.05). There was significant relationship between Slug knockdown or Slug overexpression and cells proliferation (respectively, P<0.05). Animals injected with Slug-silenced OE33 cells had fewer seeded tumor (P<0.01), more apoptosis cells (P<0.05) and significantly xenograft tumor growth regression (P<0.05). But in Slug cDNA-infected TE7 cells, more seeded tumor number and significantly xenograft tumor growth were found in xenograft tumor (respectively, P<0.05). It was showed in the subcutaneously nude mice xenograft model tumor tissue, bcl-2 expression was reduced followed by the decrease of Slug expression in Slug-silenced tumor, and bcl-2 expression was increased followed by the increase of Slug expression. In pseudometastatic model, E-cadherin overexpression was found in Slug siRNA tumor tissue, but less E-cadherin expression was found in Slug cDNA tissue. Slug is an important modulator of apoptosis, growth and invasion in EA in vitro and in vivo. Slug inhibition may represent a novel strategy for treatment of EA.

Long non-coding RNA H19 (H19) is highly expressed in cancers and is considered to highly correlate with the extent of malignant degree. The present study was performed to determine the expression levels of H19 in anaplastic thyroid carcinoma (ATC) tissues and the role of H19 in ATC 8505C cells in vitro and in vivo. Expression of H19 was detected in 19 ATC and 19 normal thyroid tissues by real-time quantitative polymerase chain reaction. Utilizing the siRNA or short hairpin RNA (shRNA) directed against human H19 (H19 siRNA or shRNA H19) depleted H19 in ATC 8505C cells and characterized the outcomes. The results showed that H19 was overexpressed in ATC tissues. Targeting H19 inhibited proliferation, migration, and invasion and induced apoptosis in 8505C cells in vitro and inhibited tumorigenesis and metastasis in vivo. Therefore, the H19 might be an effective target for ATC molecular therapy.

Transforming growth factor (TGF)-β1 plays a crucial role in the epithelial-to-mesenchymal transition (EMT) in many cancer types and in thyroid cancers. Epigallocatechin-3-gallate (EGCG), the most important ingredient in the green tea, has been reported to possess antioxidant and anticancer activities. However, the cellular and molecular mechanisms explaining its action have not been completely understood. In this study, we found that EGCG significantly suppresses EMT, invasion and migration in anaplastic thyroid carcinoma (ATC) 8505C cells in vitro by regulating the TGF-β/Smad signaling pathways. EGCG significantly inhibited TGF-β1-induced expression of EMT markers (E-cadherin reduction and vimentin induction) in 8505C cells in vitro. Treatment with EGCG completely blocked the phosphorylation of Smad2/3, translocation of Smad4. Taken together, these results suggest that EGCG suppresses EMT and invasion and migration by blocking TGFβ/Smad signaling pathways.

Effect of miR-21 and miR-138 on the proliferation of colon cancer cells and their association with prognosis were investigated. Expression levels of miR-21 and miR-138 in colorectal cancer and normal adjacent tissues were compared. Differential expression of miR-21 and miR-138 in colon cancer tissues with different clinicopathological features were analyzed. miR-21 and miR-138 expression vectors were established and transfected into cells of colon cancer cell line SW480. Methyl thiazolyl tetrazolium (MTT) assay was used to detect the proliferation of SW480 cells. Kaplan-Meier method and log-rank test were used to study the relationship between miR-21 and miR-138 expression and prognosis. Cox proportional hazards model was used to analyze the factors related to prognosis of colon cancer. Expression level of miR-21 in colon cancer tissues was significantly higher than that in adjacent tissues, and expression level of miR-138 was lower in cancer tissues than in adjacent tissues (P<0.001). Expression of miR-21 and miR-138 was associated with the degree of differentiation, lymph node metastasis, distant metastasis, and TNM stage (P<0.05). miR-21 promotes proliferation of colon cancer cell line SW480, and miR-138 inhibits cell proliferation. Survival analysis showed that the survival time of patients with high expression of miR-21 was significantly shorter than that of patients with low expression of miR-21, while survival time of patients with high expression of miR-138 was significantly longer than that of patients with low expression of miR-138 (log-rank, P<0.05). miR-21 is highly expressed in colon cancer tissues and is positively associated with the degree of malignancy of patients but negatively associated with survival. miR-138 expression is low in colon cancer tissues and is negatively associated with the degree of malignancy of patients but positively associated with survival. miR-21 and miR-138 may be involved in the regulation of colon cancer cell proliferation.