miR-106b promotes cell invasion and metastasis via PTEN mediated EMT in ESCC.

MicroRNA (miR)-106b serves an essential function in a variety of human cancer types, particularly in the process of invasion and metastasis. However, the function and mechanism of miR-106b in the invasion and metastasis of esophageal squamous cell carcinoma (ESCC) has remained elusive. In the present study, it was demonstrated that miR-106b was upregulated in ESCC tissues and cell lines. Furthermore, miR-106b expression in ESCC tissues was positively associated with lymphatic metastasis. Inhibition of miR-106b in EC-1 and EC9706 cells decreased not only the invasion and metastasis ability but also the proliferation ability of EC-1 and EC9706 cells. In addition, miR-106b had the ability to induce epithelial-to-mesenchymal transition (EMT) in EC-1 and EC9706 cells. In terms of the underlying mechanism, it was revealed that miR-106b promoted the invasion, metastasis and proliferation ability of EC-1 and EC9706 cells by directly targeting phosphatase and tension homolog (PTEN). Furthermore, miR-106b induced EMT in EC-1 and EC9706 cells by suppressing the expression of PTEN. In summary, the present study revealed that miR-106b contributed to invasion and metastasis in ESCC by regulating PTEN mediated EMT. Downregulation of miR-106b may be a novel strategy for preventing tumor invasion and metastasis.

Stathmin is a marker of progression and poor prognosis in esophageal carcinoma.

Stathmin, also called oncoprotein 18, is a founding member of the family of microtubule-destabilizing proteins that play a critical role in the regulation of mitosis. At the same time stathmin has been recognized as one of responsible factors in cancer cells. The aim of this study was to assess stathmin status, its correlations with clinicopathological parameters and its role as a progosnostic marker in EC patients. The protein and mRNA levels of stathmin were examined by immunohistochemistry (IHC) and in situ hybridization in 100EC tissues and adjacent noncancerous tissues. mRNA and protein expression of stathmin in three EC cell lines(EC9706, ECa109, EC1 commonly used in research) were also analyzed using immunocytochemistry, western blot and in situ hybridization. The prognostic value of Stathmin expression within the tumor tissues were assessed by Cox regression and Kaplan-Meier analysis. We showed that stathmin expression was significantly higher in EC tissues than in adjacent noncancerous tissues. High stathmin immunostaining score in the EC was positively correlated with tumor differentiation, Tumor invasion, Lymph node metastases, and TNM stage. In addition, we demonstrated that three EC cell lines examined, were constitutively expressing a high level of stathmin. Of those, EC-1 showed the strongest mRNA and protein expression for the stathmin analyzed. Kaplan-Meier analysis showed that significantly longer 5-year survival rate was seen in EC patients with high Stathmin expression, compared to those with low expression of Stathmin expression. Furthermore, multivariate Cox proportional hazard analyses revealed that Stathmin was an independent factors affecting the overall survival probability. In conclusion, our data provide a basis for the concept that stathmin might be associated with EC development and progression.. High levels of Stathmin expression in the tumor tissues may be a good prognostic marker for patients with EC.

Overexpression of Tiam1 predicts poor prognosis in patients with esophageal squamous cell carcinoma.

Accumulating evidence has demonstrated that T-cell lymphoma invasion and metastasis 1 (Tiam1) plays an important role in the occurrence and development of several different tumors; however, to date, little research has been done to verify the potential role of Tiam1 as a prognostic marker for esophageal squamous cell carcinoma (ESCC). In the present study, we examined the expression of Tiam1 in ESCC tissues by immunohistochemistry, in situ hybridization, semi-quantitative RT-PCR and Western blotting methods and investigated the correlation between Tiam1 levels and prognosis of patients with ESCC. Tiam1 exhibited high expression in ESCC tissues, whereas the normal esophageal tissues showed negative or weak Tiam1 expression. Additionally, Tiam1 mRNA and protein expression levels were both significantly correlated with histology grade, clinical staging and lymph node metastasis (all P<0.05), but not related to age and gender (both P>0.05). Further, ESCC patients with strong Tiam1 mRNA (P=0.000) and protein (P=0.000) expression had a poorer prognosis than those with weak expression. These findings demonstrate that Tiam1 may be used as molecular marker for predicting the prognosis of patients with ESCC.