No abstract

The scaffolding protein WWC (WW and C2-domain containing) family is known to regulate cell proliferation and organ size via the Hippo signalling pathway. However, the expression level of WWC3 in human tumours and the mechanisms underlying its role in cellular signal transduction have not yet been reported. Herein, we explored the potential roles of WWC3 in lung cancer cells and the corresponding molecular mechanisms. We found low WWC3 expression in both lung cancer cell lines and lung cancer specimens, which was associated with low differentiation, advanced pTNM stage, positive lymph node metastasis, and poor prognosis in patients with lung cancer. Moreover, the overexpression of WWC3 inhibited the proliferation and invasiveness of lung cancer cells. These effects were mediated by the inhibition and stimulation of the Wnt and Hippo pathways, respectively, in vitro and in vivo. Specifically, WWC3 interacts with Dishevelled (Dvl) proteins, prevents casein kinase 1 from phosphorylating Dvls, and inhibits -catenin nuclear translocation to inhibit the Wnt pathway. Deleting the WW and C-terminal PDZ-binding domains of WWC3 abrogated these effects. Moreover, the interaction of WWC3 with Dvls reduced the interaction between WWC3 and large tumour suppressor 1 (LATS1), as well as decreasing LATS1 phosphorylation to increase the nuclear importation of yes-associated protein (YAP) and attenuate the Hippo pathway. Deleting the WW domain of WWC3 abrogated this effect. These findings demonstrate the molecular interplay between WWC3, Dvls, and LATS1, and reveal a link between the Wnt and Hippo pathways, which provides a potential target for clinical intervention in lung cancer.

Transmembrane protein 88 (TMEM88) is a transmembrane protein that plays a crucial role in regulating human stem cell differentiation and embryonic development. However, its expression and clinicopathologic significance in human neoplasms is unclear. In this study, the expression and subcellular localizations of TMEM88 were assessed in 214 cases of non-small cell lung cancer (NSCLC). Notably, TMEM88 was highly expressed in the cytosol of $60% NSCLC specimens examined. Higher expression of cytosolic TMEM88 in NSCLC correlated significantly with poor differentiation, high TNM stage, lymph node metastasis, and inferior survival. In NSCLC cells displaying membrane-localized TMEM88, we observed an inhibition of canonical Wnt signaling due to interactions of TMEM88 with the Wnt pathway factor Dishevelled (DVLS). In contrast, NSCLC cells with cytosol-localized TMEM88 lacked effects on Wnt signaling. Cytosolic interactions of TMEM88 and DVLS increased the expression of phosphorylated, active forms of p38, GSK3b (Thr390), and Snail, thereby reducing the expression of the tight junction-associated proteins ZO-1 and occludin, effects associated with enhanced invasive and metastatic cell characters. Importantly, attenuating the expression of cytosolic TMEM88 reduced metastatic prowess in xenograft models. Overall, our findings show how mislocalization of TMEM88 to the cytosol in NSCLC cells ablates its Wnt pathway regulatory properties, thereby promoting invasion and metastasis by activating the p38-GSK3b-Snail signaling pathway. Cancer Res; 75(21); 4527-37. Ó2015 AACR.

Large tumor suppressor (LATS) is a Ser/Thr kinase originally isolated from Drosophila. Recent studies demonstrate that LATS is an important member of the Hippo pathway which can regulate organ size and cell proliferation. However, little is known about the expression and clinical significance of LATS in lung cancer. In this study, we aimed to assess the clinical significance and biological functions of LATS1 in non-small-cell lung cancer (NSCLC). We investigated the expression of LATS1 in 136 cases of NSCLC tissue and 30 cases of normal lung tissue by immunohistochemical staining. The results confirmed that LATS1 expression was higher in normal lung tissues, but significantly lower in NSCLC tissues. Moreover, the expression of LATS1 in NSCLC was significantly correlated with p-TNM stage (p = 0.038) and lymph node metastasis (p = 0.014). Importantly, the loss of LATS1 expression was associated with short overall survival. Further study in NSCLC cell lines in which LATS1 was either overexpressed or depleted confirmed that LATS1 markedly inhibited cell proliferation and invasion and could regulate the nuclear location of yes-associated protein (YAP). These results indicate that LATS1 may play an important role in NSCLC, and may serve as a novel therapeutic target of NSCLC.

Nuclear factor kappa-B (NF-κB) activation is a common phenomenon in cancers, which results in the aberrant expression of NF-κB target genes and leads to malignant transformation, metastatic dissemination, abnormal cell proliferation or resistance to cell death. Survivin is a unique member of the IAP family, a well-known cancer-specific molecule and a molecular marker of poor clinical outcome in several cancer types, including bladder cancer. YM-155, a potent survivin suppressor, has been shown to have anti-tumor activity in preclinical cell lines, xenograft models and phase I/II studies. In the present study, we investigated the function of the NF-κB/survivin pathway in bladder cancer. We found that NF-κB can promote cell cycle progression and reduce apoptosis by upregulating survivin expression, thereby increasing cellular proliferation. We further confirmed the tumorigenic function of the NF-κB/survivin pathway in vivo using a xenograft tumor model of stable NF-κB-overexpressing 5637 cells. Moreover, we found that YM-155 significantly induced apoptosis and decreased cellular proliferation as well as tumor growth in mice. Our results demonstrate the carcinogenic function of the NF-κB/survivin pathway in bladder cancer and the role of YM-155 as a promising agent for the strategic treatment of bladder cancer.

BackgroundDisorders of cell adhesion are critical steps in cancer progression in which varieties of markers including cadherins are involved in.Btbd7 was found to inhibit E-cadherin expression in MDCK cells and play important roles during branching morphogenesis of embryonic salivary glands and lungs. However its function in malignant tumors is largely unknown. The aim of this study is to investigate the clinicopathological significance and possible function of Btbd7 in non-small cell lung cancer.MethodsImmunohistochemistry and Western blotting were used to investigate Btbd7 expression in non-small cell lung cancer and lung tissues. The clinicopathological association and the overall survival was analyzed. In vitro experiments were performed using siRNA to investigate the function of Btbd7 in lung cancer cells.ResultsBtbd7 expression was elevated in non-small cell lung cancer tissues compared to normal lung tissues. Increased Btbd7 expression was significantly associated with lymph node metastasis, reduced E-cadherin expression and patients’ poor clinical outcome. Downregulation of Btbd7 expression in lung cancer cells by siRNA significantly inhibits cancer cell invasion and effectively restores E-cadherin expression in cancer cell membrane.ConclusionsBtbd7 contributes to reduced expression of E-cadherin and may be a promising cancer marker in non-small cell lung cancer.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2407-14-704) contains supplementary material, which is available to authorized users.

Our previous studies indicate that abnormal expression of several Wnt signaling molecules including Axin, Dvl and β-catenin are involved in proliferation, invasion and metastasis of lung cancer. Zbed3 was found to inhibit function of Axin-GSK3β complex and thus lead to accumulation of β-catenin in NIH3T3 and HEK293T cells. However its function in malignant tumors is largely unknown. Here we investigate the clinico-pathological significance of Zbed3 expression and its function in non-small cell lung cancer. We use immunohistochemistry and Western blotting to examine Zbed3 expression in non-small cell lung cancer and lung tissues. Transfection of siRNA and plasmid was used to study the function of Zbed3 in lung cancer cells in vitro. We found Zbed3 expression was elevated in cancer tissues compared to normal lung tissues. Increased Zbed3 expression is significantly associated with lymph node metastasis, advanced TNM stages, higher Ki67 status and patients' poor clinical outcome. Higher Zbed3 expression was also found in lung cancer cell lines compared to bronchial epithelial cell line HBE. Downregulation of Zbed3 by siRNA significantly inhibits cancer cell proliferation and invasion in vitro. Downregulation of Zbed3 also significantly inhibits expression of β-catenin, downstream molecules of Wnt signaling and P120ctn-1 in lung cancer cells. These results suggest that Zbed3 may contribute to lung cancer cell invasion through regulating β-catenin and p120ctn-1 and may be a promissing cancer marker in non-small cell lung cancer.

The objective of the current study was to investigate the expression pattern and clinicopathological significance of differentiated embryo-chondrocyte-expressed gene 1 (DEC1) in patients with non-small-cell lung cancer (NSCLC). In 118 archived NSCLC tissues, the positive rate of DEC1 was reduced in human lung cancer samples (36/118, 30.5 %) compared with adjacent normal lung tissues (106/118, 89.8 %), as measured by immunohistochemical staining. Loss of DEC1 was correlated with poor differentiation (p=0.005) and high p-TNM stage (p=0.002). Consistently, downregulation of DEC1 by siRNA knockdown promoted the growth and colony formation in the A549 lung cancer cell line, and overexpression of DEC1 inhibited the growth and colony formation in the BE1 lung cancer cell line. In addition, a significant negative correlation was found between DEC1 and cyclin D1 (p=0.014) in 118 cases of NSCLC. Knockdown of DEC1 resulted in the upregulation of cyclin D1, and overexpression of DEC1 led to the downregulation of cyclin D1. Together with the observation that DEC1 bound directly to the promoter region of cyclin D1 in A549 cells, these results indicate that loss of DEC1 may promote tumor progression in NSCLC through upregulation of cyclin D1, and DEC1 might serve as a novel therapeutic target of NSCLC.