The Tensin gene family encodes proteins thought to modulate integrin function. C-terminal Tensin-like (CTEN) is a member of the Tensin gene family which lacks the N-terminus actin-binding domain. Cten is reported to have both oncogenic and tumour-suppressor functions. We investigated the role that Cten may play in colorectal cancer (CRC). By quantitative RT-PCR CTEN is up-regulated (i.e. > two-fold increase) in 62% of cell lines and 69% of tumours compared with normal mucosa, consistent with CTEN being a possible oncogene. Stable transfection of HCT116 and SW480 (CRC cell lines with low endogenous Cten expression) with a Cten expression vector gave identical results in both cell lines. Forced Cten expression did not cause change in cell numbers, although it did confer resistance to staurosporine-induced apoptosis (p < 0.005). Cten also induced epithelial-mesenchymal transition (EMT) in tumour cells accompanied by a significant increase in both cell migration (transwell migration and cell wounding assays, p < 0.001 and p < 0.05, respectively) and cell invasion (invasion through Matrigel, p < 0.001). Given the observed EMT, we investigated the levels of E-cadherin. Cten induction was associated with a reduction in E-cadherin protein expression but not levels of E-cadherin mRNA. These data suggest that CTEN is an oncogene in CRC which stimulates EMT, cell migration and invasion and may therefore have a role in tumour invasion/spread. Furthermore, Cten induction is associated with post-transcriptional repression of E-cadherin.

CTEN/TNS4 is an oncogene in colorectal cancer (CRC), which can induce cell motility although its mechanistic basis of activity and the clinical implications of Cten expression are unknown. As Cten is in complex with integrins at focal adhesions, we hypothesised that it may interact with integrin-linked kinase (ILK). Through forced expression and knockdown of Cten in HCT116 and SW620 (respectively, showing low and high Cten expression), we showed that Cten could regulate ILK. However, inhibition of ILK after forced expression of Cten abrogated the motility-inducing effects of Cten, thereby demonstrating that the Cten-ILK interaction was functionally relevant. Combined knockdown of Cten and ILK had no additive effects on cell motility compared with knockdown of each individually. In order to investigate the clinical implications of Cten expression, a series of 462 CRCs were evaluated by immunohistochemistry. High expression of Cten was associated with advanced Dukes' stage (Po0.001), poor prognosis (Po0.001) and distant metastasis (P ¼ 0.008). The role of Cten in metastasis was tested by (a) intrasplenic injection of CRC cells stably transfected with a Cten expression vector into nude mice and (b) testing a series of primary human CRCs and their metastases by immunohistochemistry. Compared with controls, mice injected with cells expressing Cten developed larger tumours in the spleen (Po0.05) and liver (Po0.05). In the human cases, compared with primary tumours, the metastatic deposits had a significantly higher frequency of nuclear localisation of Cten (P ¼ 0.002). We conclude that Cten expression is of prognostic significance in CRC, and we delineate a Cten-ILK pathway controlling cell motility and possibly promoting metastasis. Oncogene (2011Oncogene ( ) 30, 2997 doi:10.1038/onc.2011 published online 21 February 2011 Keywords: Cten; integrin-linked kinase; metastasis Introduction C-terminal tensin-like (Cten, TNS4) is a member of the Tensin gene family. This gene family comprises four members (TNS1, TNS2, TNS3 and TNS4/Cten) and their products are localised to the cytoplasmic tails of integrins at focal adhesions. Tensins have an important role in various biological processes such as cell adhesion, migration, proliferation, differentiation, apoptosis and invasion (Lo et al., 1994;Chen et al., 2000;Lo, 2004). Human TNS1, TNS2 and TNS3 are highly homologous at their N-and C-termini, but TNS4/ COOH-terminus tensin-like molecule (Cten) is a smaller protein, which shows C-terminus homology but does not contain the N-terminus actin-binding domain that is present in the other tensin proteins (Lo and Lo, 2002). Tensin family proteins interact with several structural and signalling molecules such as vinculin, paxillin, Src, focal adhesion kinase, phosphatidylinositol-3-kinase and Crk-associated substrate p130 CAS , actin as well as integrins. As Cten is a recently described gene, data about its downstream targets are sparse, although recent studies suggest that Cten signalling occurs through the Stat3 pathway (Barbie...

CTEN/TNS4 is an oncogene in colorectal cancer (CRC) which enhances cell motility although the mechanism of Cten regulation is unknown. We found an association between high Cten expression and KRAS/BRAF mutation in a series of CRC cell lines (p = 0.03) and hypothesised that Kras may regulate Cten. To test this, Kras was knocked-down (using small interfering (si)RNA) in CRC cell lines SW620 and DLD1 (high Cten expressors and mutant for KRAS). In each cell line, Kras knockdown was mirrored by down-regulation of Cten Since Kras signals through Braf, we tested the effect of Kras knockdown in CRC cell line Colo205 (which shows high Cten expression and is mutant for BRAF but wild type for KRAS). Cten levels were unaffected by Kras knockdown whilst Braf knockdown resulted in reduced Cten expression suggesting that Kras signals via Braf to regulate Cten. Quantification of Cten mRNA and protein analysis following proteasome inhibition suggested that regulation was of Cten transcription. Kras knockdown inhibited cell motility. To test whether this could be mediated through Cten, SW620 cells were co-transfected with Kras specific siRNAs and a Cten expression vector. Restoring Cten expression was able to restore cell motility despite Kras knockdown (transwell migration and wounding assay, p<0.001 for both). Since KRAS is mutated in many cancers, we investigated whether this relationship could be demonstrated in other tumour models. The experiments were repeated in the pancreatic cancer cell lines Colo357 & PSN-1(both high Cten expressors and mutant for KRAS). In both cell lines, Kras was shown to regulate Cten and forced expression of Cten was able to rescue loss of cell motility following Kras knockdown in PSN-1 (transwell migration assay, p<0.001). We conclude that, in the colon and pancreas, Cten is a downstream target of Kras and may be a mechanism through which Kras regulates of cell motility.

Objectives: This study aimed to characterize the histopathological pattern of thyroid lesions among Saudi patients and to highlight the age and gender variations of these lesions as base line data. Materials and Methods: We retrospectively analyzed the data from thyroid specimens received at the Department of Pathology, King Fahad Hospital, Madinah, Saudi Arabia from January 2006 to December 2013. Results: The 292 thyroidectomy specimens received during the study period came from 230 (78.8%) females and 62 (21.2%) males giving a female: male ratio of 3.7:1. Age of the patients ranged from 14 to 95 years with a mean age 39.7 years. Two hundred and eleven (72.3%) cases were found to be non-neoplastic and 81 (27.7%) cases were neoplastic. The non-neoplastic group included: colloid goiter, including both diffuse and nodular goiter (170 cases; 58.2%), nodular hyperplasia (28 cases; 9.6%), Hashimoto/chronic lymphocytic thyroiditis (12 cases; 4.1%), and Grave's disease (1 case; 0.3%). In neoplastic lesions, there were 7 benign tumors and 74 malignant tumors. Among the benign tumors, 5 were follicular adenomas and 2 were Hurthle cell adenomas. Papillary carcinoma was the commonest malignant tumor accounting for 87.8% of all thyroid malignancies, followed by lymphoma, follicular carcinoma and medullary carcinoma. The size of papillary carcinoma was more than 2 cm in 40 cases (76.9%). Conclusions: Non-neoplastic thyroid lesions were more common than neoplastic ones. Colloid goiter was the most common lesion. Follicular adenoma was the commonest benign tumor and papillary carcinoma was the commonest malignant lesion. There appears to be a slightly increased trend of papillary carcinoma diagnosis, most being diagnosed at an advanced stage.

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These are the first data showing an oncogenic role for CTEN in pancreatic cancer through promotion of colony formation and cell motility. The latter may be mediated by signaling through focal adhesion kinase and inhibiting E-cadherin.

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