2017

CTTN

cortactin;CTTN;cortactin

1110020L01Rik|amplaxin|ems1 sequence (mammary tumor and squamous cell carcinoma-associated (p80/85 src substrate)|oncogene EMS1|src substrate cortactin

11q13

protein-coding

Cortactin is a ubiquitous actin-binding protein that was originally identified as a substrate for the protein kinase Src. It is accumulated in peripheral, actin-enriched structures of cells, including lamellipodia and membrane ruffles, suggesting that cortactin facilitates actin network formation. In addition, recent data suggests that it regulates various aspects of cell dynamics, including integrin signaling, vesicular transport, axon guidance, and cell migration. A large body of evidence indicates that cortactin is also implicated in the pathogenesis of human neoplasia. It is over-expressed in a number of epithelial carcinomas, including breast cancer and head and neck cancer. Over-expression of cortactin in human tumors has been proposed to result in increased cell migration and metastatic potential. This review aims to focus on cortactin-mediated signaling pathways, with emphasis on its contribution to tumor progression and metastasis formation.

Angiogenesis and cancer invasiveness greatly contribute to cancer malignancy.Arf6 and its effector, AMAP1, are frequently overexpressed in breast cancer, and constitute a central pathway to induce the invasion and metastasis. In this pathway, Arf6 is activated by EGFR via GEP100. Arf6 is highly expressed also in human umbilical vein endothelial cells (HUVECs) and is implicated in angiogenesis. Here, we found that HUVECs also highly express AMAP1, and that vascular endothelial growth factor receptor-2 (VEGFR2) recruits GEP100 to activate Arf6. AMAP1 functions by binding to cortactin in cancer invasion and metastasis. We demonstrate that the same GEP100-Arf6-AMAP1-cortactin pathway is essential for angiogenesis activities, including cell migration and tubular formation, as well as for the enhancement of cell permeability and VE-cadherin endocytosis of VEGF-stimulated HUVECs. Components of this pathway are highly expressed in pathologic angiogenesis, and blocking of this pathway effectively inhibits VEGF- or tumor-induced angiogenesis and choroidal neovascularization. The GEP100-Arf6-AMAP1-cortactin pathway, activated by receptor tyrosine kinases, appears to be common in angiogenesis and cancer invasion and metastasis, and provides their new therapeutic targets.

Gain of chromosome 11q13 is a common event in esophageal squamous cell carcinoma (ESCC). The cortactin gene (CTTN, also EMS1), located at 11q13, plays a pivotal role in coupling membrane dynamics to cortical actin assembly. This gene has been implicated in the motility of several types of cells. In the present study, we found that the amplification and overexpression of the CTTN gene was associated with lymph node metastasis in ESCC. Functional analysis by small interfering RNA-mediated silencing of CTTN revealed that in addition to the effect on cell migration, CTTN influenced cell invasiveness by anoikis resistance. In vivo assay showed that inhibition of CTTN expression also decreased tumor growth and lung metastasis of ESCC cells. At the molecular level, we showed for the first time that the protective role of CTTN in anoikis resistance was correlated with the activation of the phosphatidylinositol 3-kinase/Akt pathway. Overall, the data suggest that CTTN is an oncogene in the 11q13 amplicon and exerts functions on tumor metastasis in ESCC.

Cortactin, fascin, and survivin have been documented in several human cancers and play important roles in tumor progression. We collected 57 surgical specimens, including esophageal squamous cell carcinomas (SqCC; 7 well-differentiated, 15 moderately differentiated, and 24 poorly differentiated), 3 dysplasias, and 8 normal esophageal tissues. Tissue microarrays were constructed and the immunostaining scores for cortactin, fascin, and survivin were assessed. In 46 SqCC specimens, we examined the relationship between the expression of three biomarkers and tumor differentiation or clinical parameters. Higher immunostaining scores for cortactin, fascin, and survivin correlated positively with tumor differentiation of esophageal SqCC. Univariate survival analysis showed significantly worse prognosis in patients with high scores of cortactin (>or=290), fascin (>or=245), and survivin (score >or= 175), poor differentiation, T4 stage, positive for lymph node metastasis, and positive for distant metastasis. In multivariate survival analysis, high scores of survivin (>or=175) and poor differentiation were independent risk factors for worse prognosis. Our results demonstrated that higher expression of survivin may be related to tumor progression and it is an independent risk factor for poor survival time of esophageal SqCC. Survivin may be a good biomarker to be applied in clinic to predict the prognosis of esophageal SqCC.

AIM: Esophageal squamous cell carcinoma (ESCC) is one of the most common fatal malignances of the digestive tract. Its prognosis is poor mainly due to the lack of reliable markers for early detection and prognostic prediction. Here we aim to identify the molecules involved in ESCC carcinogenesis and those as potential markers for prognosis and as new molecular therapeutic targets. METHODS: We performed genome-wide gene expression profile analyses of 10 primary ESCCs and their adjacent normal tissues by cDNA microarrays representing 47,000 transcripts and variants. Candidate genes were then validated by semi quantitative reverse transcription-PCR (RT-PCR), tissue microarrays (TMAs) and immunohistochemistry (IHC) staining. RESULTS: Using an arbitrary cutoff line of signal log ratio of >/=1.5 or expression of cortactin (CTTN) was observed in 126/198 (63.6%) of ESCC cases and was significantly associated with lymph node metastasis (P = 0.000), pathologic stage (P = 0.000) and poor survival (P<0.001) of ESCC patients. Furthermore, a significant correlation between CTTN overexpression and shorter disease-specific survival rate was found in different subgroups of ESCC patient stratified by the pathologic stage (P<0.05). CONCLUSION: Our data provide valuable information for establishing molecules as candidates for prognostic and/or as therapeutic targets.

BACKGROUND & OBJECTIVE: EMS1 (chromosome eleven, band q13, mammary tumor and squamous cell carcinoma-associated gene 1) is correlated to the genesis, progression, invasion and metastasis of some malignancies. This study was to investigate the expression of EMS1 protein in gastric carcinoma, and to explore its correlation to the carcinogenesis of gastric carcinoma. METHODS: The expression of EMS1 protein in 20 specimens of normal gastric mucosa, 38 specimens of intraepithelial neoplasia, and 146 specimens of gastric carcinoma was detected by immunohistochemistry. RESULTS: EMS1 protein was expressed in cytoplasm. The positive rate of EMS1 protein was significantly higher in gastric carcinoma than in intraepithelial neoplasia and normal gastric mucosa (89.7% vs. 68.4% and 20.0%, P<0.001), and significantly higher in intraepithelial neoplasia than in normal gastric mucosa (P<0.001). The positive rate of EMS1 protein was significantly lower in the gastric carcinomas at early stages than in those at advanced stages (60.9% vs. 95.1%, P<0.001), and significantly higher in the gastric carcinomas with lymph node metastases than in those without lymph node metastases (96.8% vs. 77.0%, P<0.001). EMS1 protein expression had no correlations to sex, age, tumor differentiation and diameter. CONCLUSION: EMS1 protein expression is related to the carcinogenesis, lymph node metastasis and clinical stage of gastric carcinoma.

BACKGROUND/AIMS: The molecular basis of the metastasis of hepatocellular carcinoma (HCC) is not fully understood. The aim of this study was to elucidate the crucial genes involved in metastasis of HCC. METHODS: We compared expression profiles among highly metastatic HCC cell lines and non-metastatic HCC cell lines by using oligonucleotide array to identify genes associated with metastasis. We further investigated the effect of identified gene on cell motility and metastasis in vitro and in vivo. Finally, we examined immunohistochemistry in human tissue samples. RESULTS: We identified 39 genes whose expression levels were significantly correlated with metastatic ability (P<0.05). Of these genes, we further investigated cortactin, because this cortical actin-associated protein is a substrate of Src, whose activation has been shown to be involved in HCC cell migration and metastasis. Overexpression of cortactin in a non-metastatic HCC cell line increased cell motility, and resulted in metastasis in an orthotopic model. Furthermore, immunohistochemical expression of cortactin revealed its significant overexpression in HCC with intrahepatic metastasis compared with HCC without intrahepatic metastasis (P<0.005). CONCLUSIONS: Overexpression of cortactin may play a role in the metastasis of HCC by influencing cell motility, and cortactin could be a sensitive marker for HCC with intrahepatic metastasis.

BACKGROUND: Cortactin is an important regulator involved in invasion and migration of hepatocellular carcinoma (HCC). The aim of this study was to elucidate the forecasting role of cortactin in resectable HCCs. METHODS: We compared the invasiveness and motility among liver epithelial cell line and HCC cell lines by using Transwell assay and wound healing assay. We further investigated the CTTN mRNA expression by real-time PCR. Next, 91 HCC and 20 normal liver tissue samples were detected by IHC and real-time PCR. Finally, we analyzed the clinicopathologic features and survival time of the HCC cases. RESULTS: We identified that HepG2, LM3, and SK-Hep-1 had more invasiveness and motility (P <0.05). Compared with liver epithelial cell line, CTTN expression was higher in LM3, HepG2, and MHCC97-L (P <0.01) and lower in SK-Hep-1 (P <0.05). IHC examination showed cortactin expression was closely relative to TNM stage (AJCC/UICC), cancer embolus, and metastasis (P <0.01). Cortactin overexpression indicated a longer survival time of 52 +/- 8.62 months and low expression of a shorter survival time of 20 +/- 4.95 months (P <0.01). Cortactin examination has more predictive power in patients with Child-Pugh grade A and BCLC stage 0-B. CONCLUSIONS: Overexpression of cortactin is closely associated with poor human HCCs prognosis that caused by cancer embolus and metastasis. Cortactin and CTTN should be used for differentiating varieties of survival for patients after HCC resection.

Angiogenesis and cancer invasiveness greatly contribute to cancer malignancy.Arf6 and its effector, AMAP1, are frequently overexpressed in breast cancer, and constitute a central pathway to induce the invasion and metastasis. In this pathway, Arf6 is activated by EGFR via GEP100. Arf6 is highly expressed also in human umbilical vein endothelial cells (HUVECs) and is implicated in angiogenesis. Here, we found that HUVECs also highly express AMAP1, and that vascular endothelial growth factor receptor-2 (VEGFR2) recruits GEP100 to activate Arf6. AMAP1 functions by binding to cortactin in cancer invasion and metastasis. We demonstrate that the same GEP100-Arf6-AMAP1-cortactin pathway is essential for angiogenesis activities, including cell migration and tubular formation, as well as for the enhancement of cell permeability and VE-cadherin endocytosis of VEGF-stimulated HUVECs. Components of this pathway are highly expressed in pathologic angiogenesis, and blocking of this pathway effectively inhibits VEGF- or tumor-induced angiogenesis and choroidal neovascularization. The GEP100-Arf6-AMAP1-cortactin pathway, activated by receptor tyrosine kinases, appears to be common in angiogenesis and cancer invasion and metastasis, and provides their new therapeutic targets.