Epithelial Cell Transforming Sequence 2 Expression Research Articles

ECT2 promotes malignant phenotypes through the activation of the AKT/mTOR pathway and cisplatin resistance in cervical cancer.

Epithelial cell transforming sequence 2 (ECT2) is expressed at high levels in various malignancies and contributes to malignant phenotypes in cancers. However, ECT2 is still not fully understood regarding its function and carcinogenic mechanism in cervical cancer. This research indicated that ECT2 expression was elevated in cervical cancer based on bioinformatics analysis and clinical specimens. Experiments in vitro and in vivo confirmed that ECT2 knockdown could suppress the proliferation and metastasis of cervical carcinoma cells. In addition, we found that silencing ECT2 could enhance the sensitivity to cisplatin and promote cell apoptosis. Mechanistically, we observed that ECT2 knockdown could inhibit the AKT/mTOR pathway and activate apoptosis, while ECT2 overexpression induced the opposite effect. The relationship between ECT2 and AKT was further confirmed by immunoprecipitation and rescue experiments. We found that the ECT2 and AKT could interact to form a complex, and knockdown AKT could offset all of the effects induced by ECT2. Our study emphasized the key point of ECT2 in the reversal of cisplatin resistance, and ECT2 could become a potential therapeutic target in cervical cancer.

Upregulation of ECT2 Predicts Adverse Clinical Outcomes and Increases 5-Fluorouracil Resistance in Gastric Cancer Patients.

Background The abnormal expression and prognosis prediction of epithelial cell transforming sequence 2 (ECT2) in gastric cancer (GC) has been reported. However, the effect of ECT2 on 5-fluorouracil (5-Fu) resistance in GC is unclear. This research aims to solve the abovementioned problems. Methods Gene expression was detected by RT-qPCR and Western blot analysis. Cell viability was evaluated by the colony formation assay, MTT assay, and flow cytometric analysis. Transwell and wound healing assays were used to detect cell metastasis. Results Upregulation of ECT2 was found in stomach adenocarcinoma (STAD) and GC tissues. In addition, high ECT2 expression can predict adverse clinical outcomes in GC patients. More importantly, ECT2 knockdown weakened the resistance of 5-FU in GC cells. ECT2 silencing reduced the cell migratory and invasive abilities of GC cells treated with 5-FU. We also found that downregulation of ECT2 increased 5-FU sensitivity in GC cells by downregulating P-gp, MRP1, and Bcl-2. Conclusion Upregulation of ECT2 can predict adverse clinical outcomes and increase 5-FU resistance in GC patients.

MiR-30a-5p Regulates Viability, Migration, and Invasion of Lung Adenocarcinoma Cells via Targeting ECT2.

Objective The abnormal expression of epithelial cell transforming sequence 2 (ECT2) is often considered the driving factor for the growth and invasion of tumors. This study was performed to investigate the regulatory effect of miR-30a-5p and ECT2 on lung adenocarcinoma (LUAD), which provides a basis for the effective clinical treatment of LUAD. Methods The mature miRNAs, expression data of mRNAs, and clinical data of LUAD were downloaded from The Cancer Genome Atlas (TCGA). The expression levels of ECT2 mRNA and miR-30a-5p in cancer cell lines were detected by qRT-PCR. Western blot was performed to test the expression of ECT2 protein. The targeting relationship between miR-30a-5p and ECT2 was verified by dual-luciferase assay. The CCK-8 method and Transwell assay were conducted to test the viability, migratory, and invasive abilities of cells. Results ECT2 expression was upregulated in LUAD and was significantly correlated with the LUAD clinical stage and pathologic T stage, and the expression of its upstream regulatory gene miR-30a-5p was downregulated. miR-30a-5p targeted ECT2 in LUAD. Downregulation of ECT2 could inhibit the viability, migration, and invasion of LUAD cells, which could be reversed by simultaneously suppressing the expression of miR-30a-5p. Conclusion Our results suggested that miR-30a-5p repressed the malignant progression of LUAD via downregulating ECT2. miR-30a-5p and ECT2 may be effective targets for LUAD patients.

Effect of Ect2 Expression on the Growth of Triple-Negative Breast Cancer Cells with Paclitaxel Intervention.

ObjectTo identify the expression levels of ECT2 (epithelial cell transforming sequence 2) in triple-negative breast cancer (TNBC) before and after administration of paclitaxel (PTX) and explore the interaction between ECT2 and PTX in breast cancer treatment.MethodsLentiviral (LV) packaging ECT2 overexpression and interference plasmids were constructed for in vitro assays. The effects of ECT2 expression on the TNBC cell line (HCC1806), particularly its roles in the proliferation, invasion, migration and apoptosis and cell cycle, were evaluated using the CCK-8 and other methods before and after PTX treatment. In nude mouse xenograft settings were performed to detect cell apoptosis and Ki-67 expression levels by TUNEL and immunohistochemical staining, respectively.ResultsIn the vitro assays, before and after the PTX treatment, comparison of the LV-ECT2 and sh-ECT2 groups and the remaining three groups (control, LV-NC, sh-NC) showed statistically significant differences in terms of cell proliferation, invasion and migration and apoptosis and changes in the cell cycle. In the vivo assays, the control, LV-ECT2 and sh-ECT2 groups markedly outweighed the corresponding PTX-treated groups. The LV-ECT2, PTX, sh-ECT2 and sh-ECT2-PTX were all significantly different from the control group in terms of body weight and tumour size changes. Cell apoptosis occurred in the PTX, sh-ECT2 and sh-ECT2-PTX groups. About the Ki-67 proliferation index, the PTX, LV-ECT2-PTX, sh-ECT2 and sh-ECT2-PTX groups were significantly different from the control group.ConclusionECT2, which is a major driving factor in the growth of breast cancer cells, plays an important role in regulating TNBC growth. PTX therapy had significantly improved efficacy after silencing ECT2. This finding indicates that the inhibition of ECT2 expression may facilitate the treatment of breast cancer as a new regimen and provide a theoretical basis for the development of new targeted drugs as a replacement for PTX in breast cancer treatment.

The Oncogene ECT2 Contributes to a Hyperplastic, Proliferative Lung Epithelial Cell Phenotype in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) and lung cancer are progressive lung diseases with a poor prognosis. IPF is a risk factor for the development of lung cancer, and the incidence of lung cancer is increased in patients with IPF. The disease pathogenesis of IPF and lung cancer involves common genetic alterations, dysregulated pathways, and the emergence of hyperplastic and metaplastic epithelial cells. Here, we aimed to identify novel, common mediators that might contribute to epithelial cell reprogramming in IPF. Gene set enrichment analysis of publicly available non-small cell lung cancer and IPF datasets revealed a common pattern of misregulated genes linked to cell proliferation and transformation. The oncogene ECT2 (epithelial cell transforming sequence 2), a guanine nucleotide exchange factor for Rho GTPases, was highly enriched in both IPF and non-small cell lung cancer compared with nondiseased controls. Increased expression of ECT2 was verified by qPCR and Western blotting in bleomycin-induced lung fibrosis and human IPF tissue. Immunohistochemistry demonstrated strong expression of ECT2 staining in hyperplastic alveolar epithelial type II (ATII) cells in IPF, as well as its colocalization with proliferating cell nuclear antigen, a well-known proliferation marker. Increased ECT2 expression coincided with enhanced proliferation of primary mouse ATII cells as analyzed by flow cytometry. ECT2 knockdown in ATII cells resulted in decreased proliferation and collagen I expression in vitro. These data suggest that the oncogene ECT2 contributes to epithelial cell reprogramming in IPF, and further emphasize the hyperplastic, proliferative ATII cell as a potential target in patients with IPF and lung cancer.

Epithelial cell transforming sequence 2 expression is associated with the progression of laryngeal squamous cell carcinoma.

Epithelial cell transforming sequence 2 (ECT2) is a guanine nucleotide exchange factor and its expression is associated with the development of malignant tumor types. However, to the best of our knowledge, there is no information on the role of ECT2 in the development and progression of laryngeal squamous cell carcinoma (LSCC). The present study aimed at investigating the expression pattern and potential role of ECT2 in the development and progression of LSCC. The expression of ECT2 in 81 pairs of LSCC and adjacent non-tumor tissues was characterized by immunohistochemistry and reverse transcription-quantitative polymerase chain reaction. ECT2 expression was upregulated in LSCC tissues and associated significantly with poor differentiation, higher stages, lymph node metastasis and poor survival in the sample population. The relative expression levels of ECT2 mRNA transcripts were correlated with the intensity of anti-ECT2 staining in 25 ECT2+LSCC specimens selected randomly. These results indicated that ECT2 expression was crucial for the progression of LSCC and may serve as a biomarker for the diagnosis and prognosis of LSCC.

Cytoplasmic expression of epithelial cell transforming sequence 2 in lung adenocarcinoma and its implications for malignant progression

Epithelial cell transforming sequence 2 (ECT2), a guanine nucleotide exchange factor, is predominantly localized in the nucleus of non-transformed cells and functions to regulate cytokinesis. ECT2 is also localized in the cytoplasm of cancer cells. Aberrant cytoplasmic expression of ECT2 is thought to drive tumor growth and invasion. In this study, we investigated the cytoplasmic expression of ECT2 and its prognostic and biological significance in lung adenocarcinoma. Western blotting of cellular fractions from the nucleus and cytoplasm was performed to determine the subcellular localization of ECT2 in lung adenocarcinoma cell lines. The cytoplasmic expression of ECT2 in 167 lung adenocarcinomas was evaluated by immunohistochemistry and its clinical significance was examined using Kaplan–Meier curves and Cox regression analysis. Scraping cytology specimens of 13 fresh lung adenocarcinomas were used to assess the subcellular localization of ECT2 and its phosphorylation at Thr790 (P-ECT2(T790)). We found that ECT2 was localized in both the nucleus and cytoplasm of lung adenocarcinoma cell lines and tumor tissues. Cytoplasmic expression of ECT2 was detected by immunohistochemistry in 83 (50%) of the lung adenocarcinomas, and was found to increase during cancer progression. It was expressed in 30 (29%) small adenocarcinomas ( ≤ 2 cm in diameter) and 53 (82%) advanced adenocarcinomas ( > 2 cm in diameter). Cytoplasmic positivity for ECT2 was associated with a poor outcome in terms of both disease-free and overall survival (both P < 0.001), and was an independent prognostic factor for overall survival (P = 0.025). Immunocytochemical staining for P-ECT2(T790) demonstrated cytoplasmic and membrane positivity in Calu-3 cells and scraping cytology specimens. Positive P-ECT2(T790) staining was correlated with cytoplasmic ECT2 expression in 6 of 13 scraped cytology specimens tested. In conclusion, our findings indicate that cytoplasmic ECT2 expression could promote the malignant progression of lung adenocarcinoma and may represent a potent therapeutic target for patients with lung adenocarcinoma.

Progression and prognostic value of ECT2 in non-small-cell lung cancer and its correlation with PCNA.

PurposeEpithelial cell transforming sequence 2 (ECT2) is a guanine nucleotide exchange factor, which is involved in cell division regulation and cell cycle modulation. Recent evidence indicates that ECT2 is overexpressed in many human cancers. However, the exact prognostic value of ECT2 in lung cancer has not been elucidated.Patients and methodsIn the current study, we performed correlation and prognosis analyses using public databases and conducted immunohistochemical staining in tissue microarrays, using samples from 204 lung cancer patients with survival data.ResultsWe found that the expression of ECT2 was markedly increased in lung cancer tissues compared with normal tissues. Moreover, we demonstrated that the expression of ECT2 was related to tumor cell differentiation degree, TNM stage, lymph node metastasis, and prognosis in non-small-cell lung cancer (NSCLC). A correlation analysis indicated that ECT2 levels were significantly correlated with proliferating cell nuclear antigen (PCNA) levels in NSCLC. Furthermore, Kaplan–Meier analyses revealed that high ECT2 expression was associated with unfavorable overall survival (OS) and progression-free survival (PFS) in NSCLC patients.ConclusionTaken together, these results indicate that the overexpression of ECT2 contributes to tumor invasion and progression, suggesting that ECT2 is a potential prognostic marker for NSCLC patients.

Role of Epithelial Cell Transforming Sequence 2 (ECT2) in Predicting Prognosis of Osteosarcoma.

BackgroundOsteosarcoma is a major bone malignancy in children and young adults, and it is highly heterogeneous. The clinical outcome of osteosarcoma is individual-dependent due to different genetic and pathological profiles. Although chemotherapy in combination with surgery has significantly improved the survival of localized disease, the prognostic improvement for metastatic patients is less marked. ECT2 (epithelial cell transforming sequence 2) is a transforming protein that can interact with Rho-like proteins of the Ras family and has been proven as an ontogenetic protein in cancer cell lines. We studied the clinical significance of ECT2 in osteosarcoma and explored its underlying oncogenic mechanisms.Material/MethodsThe protein expression pattern of ECT2 in osteosarcoma was investigated by immunohistochemical staining, and its association with clinicopathological characteristics was initially explored. The significance of ECT2 in predicting patient prognosis was verified by univariate and multivariate analyzes. Cellular experiments were conducted to explore underlying mechanisms of ECT2 in regulating osteosarcoma progression.ResultsHigh ECT2 expression was correlated with tumor metastasis and poor overall survival of osteosarcoma patients. ECT2 promotes cell invasion by modulating EMT process.ConclusionsECT2 is an independent prognostic factor for osteosarcoma and it can upregulate the metastatic capacity of osteosarcoma cells.

Oncogenic role of epithelial cell transforming sequence 2 in lung adenocarcinoma cells.

Lung adenocarcinoma, which is the most common non-small cell lung cancer, is the leading cause of death from cancer worldwide. Epithelial cell transforming sequence 2 (ECT2) is frequently upregulated and acts as an oncogene in various human cancers. In addition, ECT2 was reported to be upregulated in early stage lung adenocarcinoma. However, the detailed role of ECT2 in mediating the malignant phenotypes of lung adenocarcinoma cells has not previously been elucidated. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were used to examine ECT2 mRNA and protein expression levels, respectively. MTT, wound healing and Transwell assays were conducted to determine cell proliferation, migration and invasion abilities, respectively. In the present study, ECT2 was significantly upregulated in lung adenocarcinoma cell lines (H650, EKVX, HCC4006, HCC827, HCC2935, Hop62 and A549), as compared with a normal lung epithelial cell line (BEAS-2B). Moreover, knockdown of ECT2, induced by transfection with ECT2 siRNA, significantly inhibited the proliferation of lung adenocarcinoma A549 cells, whereas overexpression of ECT2 enhanced A549 cell proliferation. Furthermore, knockdown of ECT2 expression suppressed the migration and invasion of A549 cells, whereas overexpression of ECT2 enhanced the migration and invasion abilities of A549 cells. Notably, inhibition of ECT2 also suppressed the expression levels of N-cadherin and vimentin, whereas it enhanced the expression level of E-cadherin, indicating that ECT2 is associated with the epithelial-mesenchymal transition in A549 cells. On the contrary, overexpression of ECT2 enhanced the expression levels of N-cadherin and vimentin, whereas it reduced the expression level of E-cadherin in A549 cells. In conclusion, the results of the present study suggest that ECT2 has an oncogenic role in lung adenocarcinoma cells. Therefore, ECT2 may be a potential novel target for the treatment of lung adenocarcinoma.

Clinical significance of ECT2 expression in tissue and serum of gastric cancer patients.

The ECT2 (epithelial cell transforming sequence 2) oncogene acted as a guanine nucleotide exchange factor for RhoGTPases, and regulates cytokinesis; thus, it may play a role in the pathogenesis of gastric cancer. In this study, we investigated the expression ECT2 gene in tissues and serum of gastric cancer patients to explore its clinical significance. ECT2 mRNA expression levels in tissues and serum were examined by RT-PCR, and ECT2 protein expression in tissue was evaluated by Western blot, and was further validated by immunohistochemistry and enzyme-linked immunosorbent assay at serum level. ECT2 level was significantly increased in the GC tissues and serum compared to normal control. ECT2 expression was positively correlated with the histologic differentiation, stages of TNM, and lymph node metastasis in GC (P<0.05). Our results suggest that ECT2 plays an important role during GC progression and it may become a new diagnostic marker and therapeutic molecular target for management of GC.

Elevated expression of ECT2 predicts unfavorable prognosis in patients with colorectal cancer.

Epithelial cell transforming sequence 2 (ECT2) is a well-studied guanine nucleotide exchange factor for the Rho family GTPase, which has been demonstrated as an oncogene in many types of human cancers. However, little is known about the prognostic value of ECT2 in colorectal cancer (CRC). In current study, we investigated the expression pattern and underlying clinical significance of ECT2 in CRC. ECT2 expression was detected in 345 CRC specimens by immunohistochemistry, and its correlation with clinicopathologic parameters and prognosis of CRC patients were analyzed. Data from Oncomine database and real-time PCR demonstrated that ECT2 expression was elevated in CRC compared with normal tissues. Among the clinical parameters analyzed, high expression level of ECT2 significantly associated with tumor size (P=0.020), serum CEA levels (P = 0.000) and TNM stage (P=0.027). Kaplan-Meier survival analysis showed that patients with high ECT2 expression had a remarkably shorter overall survival. Cox regression analysis revealed that ECT2 expression level was a significant and independent prognostic factor for overall survival rate of CRC patients. These data suggested that ECT2 is an unfavorable biomarker of prognosis in CRC and that ECT2 may be a potential therapeutic candidate for CRC treatment.

Small interfering RNA-induced inhibition of epithelial cell transforming sequence2 suppresses the proliferation, migration and invasion of osteosarcoma cells.

Osteosarcoma (OS) is the most common malignant tumor in bones. Although the five-year survival rate has improved to ∼60% for patients without metastasis, the prognosis remains poor for patients with metastatic OS. Epithelial cell transforming sequence 2 (ECT2) has been shown to act as an oncogene in human malignancies. More recently, ETC2 was shown to be involved in the development and progression of OS; however, the detailed role of ECT2 in the regulation of cellular biological processes in OS cells remains largely unknown. Therefore, it was investigated in the present study. It was found that the expression of ECT2 was notably increased in OS tissues when compared with that in matched normal adjacent tissues. Furthermore, it was established that the downregulation of ECT2 induced by transfection with ECT2-specific small interfering RNA effectively inhibited OS cell proliferation and induced cell apoptosis. Further investigation revealed that the inhibition of ECT2 expression suppressed OS cell migration and invasion, indicating that the overexpression of ECT2 promotes OS cell migration and invasion, while. In addition, western blotting results indicated that matrix metalloproteinases 2 and 9 may be involved in the ECT2-mediated OS cell invasion. In conclusion, the current study suggested that ECT2 acted as an oncogene in OS, and it may become a promising therapeutic target for the prevention and treatment of OS.

ECT2 regulates the Rho/ERK signalling axis to promote early recurrence in human hepatocellular carcinoma

Early recurrence is the major obstacle for improving the outcome of patients with hepatocellular carcinoma (HCC). Therefore, identifying key molecules contributing to early HCC recurrence can enable the development of novel therapeutic strategies for the clinical management of HCC. Epithelial cell transforming sequence 2 (ECT2) has been implicated in human cancers, but its function in HCC is largely unknown. ECT2 expression was studied by microarrays, immunoblotting and immunohistochemistry in human HCC samples. siRNA- and lentiviral vector-mediated knockdown were employed to decipher the molecular functions of ECT2. The upregulation of ECT2 is significantly associated with early recurrent HCC disease and poor survival. Knockdown of ECT2 markedly suppressed Rho GTPases activities, enhanced apoptosis, attenuated oncogenicity and reduced the metastatic ability of HCC cells. Moreover, knockdown of ECT2 or Rho also suppressed ERK activation, while the silencing of Rho or ERK led to a marked reduction in cell migration. Stable knockdown of ECT2 in vivo resulted in significant retardation of tumour growth and the suppression of ERK activation. High expression of ECT2 correlates with high ERK phosphorylation and poor survival of HCC patients. Furthermore, ECT2 enhances the expression and stability of RACGAP1, accelerating ECT2-mediated Rho activation to promote metastasis. ECT2 is closely associated with the activation of the Rho/ERK signalling axis to promote early HCC recurrence. In addition, ECT2 can crosstalk with RACGAP1 to catalyse the GTP exchange involved in Rho signalling to further regulate tumour initiation and metastasis.

Abstract 2835: Discovery of novel inhibitors for ECT2 as a novel therapeutic strategy for lung cancer

Abstract The Epithelial Cell Transforming sequence 2 (ECT2) proto-oncogene is a Guanine Exchange Factor (GEF) for RhoA, Rac1 and Cdc42 and is essential to the regulation of cytokinesis. ECT2 contains the Dbl homology and pleckstrin homology (PH) domains, which are the hallmarks of GEFs. ECT2 is over-expressed in primary non-small cell lung cancer (NSCLC) tumors, and injection of ECT2 transfectants into nude mice efficiently induces tumor formation. High level of ECT2 expression is associated with poor prognosis for patients with NSCLC. Knock down of ECT2 expression by small interfering RNAs effectively suppresses lung cancer cell growth, suggesting a specific role of ECT2 in lung cancer development. Taken together, ECT2 may represent an attractive molecular target for inhibiting lung tumor growth. Our studies are based on the hypothesis that ECT2 plays an important role in lung cancer progression and is a novel target for the development of drugs to treat lung cancer. We have built a model for ECT2 PH domain using protein homology modeling. Docking of new compounds selected from commercial drug-like libraries has led to the identification of novel inhibitors of ECT2 PH domain. We have identified several compounds that bind ECT2 PH domain in the low micromolar range (KD&amp;lt;1μM) as measured using surface plasmon resonance spectroscopy and that inhibit the proliferation of a panel of 23 lung cancer cell lines (EC50&amp;lt;50μM). Importantly, inhibition occurred only in mutant-KRAS cells. Two compounds were shown to inhibit actin polymerization using a phalloidin-rhodamine stain as well as in vitro tumor formation using a colony forming assay and migration using a wound healing assay. These two compounds are being evaluated for their anti-tumor activity against several human lung cancer xenografts in SCID mice. The objectives of our studies are 1) to conduct molecular mechanistic studies of the precise role of ECT2 in the development of lung cancer in vivo animal model of lung cancer; 2) to test the most active compounds in cells in culture to provide a mechanistic rationale for their biological activity and 3) to test the anti-tumor properties of the lead compounds in a in vivo model of lung cancer. The overall goals of our work are to validate ECT2 as a therapeutic target for lung cancer and to develop a novel therapeutic strategy and agents for the improved treatment and the eventual cure of lung cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2835. doi:1538-7445.AM2012-2835

Epithelial Cell Transforming Sequence 2 in Human Oral Cancer

BackgroundEpithelial cell transforming sequence 2 (ECT2) is a guanine nucleotide exchange factor for Rho family GTPase, which has been implicated in the malignant phenotype of human cancers. Little is known about the effect of a high level of ECT2 in regulating oral cancer cell behavior. In this study, we investigated the involvement of ECT2 in oral squamous cell carcinoma (OSCC).Methodology/Principal FindingsWe analyzed ECT2 expression in OSCC-derived cell lines and primary OSCCs compared with matched normal tissue (n = 96) by quantitative reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry. We then evaluated the correlation between the ECT2 expression status in primary OSCCs and the clinicopathological features. ECT2 expression was significantly up-regulated in OSCCs in vitro and in vivo (p<0.05). Among the clinical variables analyzed, higher ECT2 expression also was associated with the TNM stage grading (p<0.05). When we performed functional analyses of ECT2 in OSCC-derived cells using the shRNA system, the cellular proliferation of the ECT2 knockdown cells decreased significantly compared with the control cells (p<0.05). Cell cycle analysis by flow cytometry showed arrest of cell cycle progression at the G1 phase in the ECT2 knockdown cells. We also found up-regulation of the Cip/Kip family of the cyclin-dependent kinase inhibitors, p21cip1 and p27kip1, and down-regulation of cyclin D1, cyclin E, and CDK4. These data suggested that the elevated Cip/Kip family induced inhibition of the cyclin D1-CDK complex activity leading to cell cycle arrest at the G1 phase.Conclusions/SignificanceOur results proposed for the first time that ECT2 is an indicator of cellular proliferation in OSCCs and that ECT2 might be a potential therapeutic target for the development of new treatments for OSCCs.

Involvement of Epithelial Cell Transforming Sequence-2 Oncoantigen in Lung and Esophageal Cancer Progression

This study aims to isolate potential molecular targets for diagnosis, treatment, and/or prevention of lung and esophageal carcinomas. We screened for genes that were frequently overexpressed in the tumors through gene expression profile analyses of 101 lung cancers and 19 esophageal squamous cell carcinomas (ESCC) by cDNA microarray consisting of 27,648 genes or expressed sequence tags. In this process, we identified epithelial cell transforming sequence 2 (ECT2) as a candidate. Tumor tissue microarray was applied to examine the expression of ECT2 protein in 242 archived non-small-cell lung cancers (NSCLC) and 240 ESCC specimens and to investigate its prognostic value. A role of ECT2 in lung and esophageal cancer cell growth and/or survival was examined by small interfering RNA experiments. Cellular invasive activity of ECT2 in mammalian cells was examined using Matrigel assays. Northern blot and immunohistochemical analyses detected expression of ECT2 only in testis among 23 normal tissues. Immunohistochemical staining showed that a high level of ECT2 expression was associated with poor prognosis for patients with NSCLC (P = 0.0004) as well as ESCC (P = 0.0088). Multivariate analysis indicated it to be an independent prognostic factor for NSCLC (P = 0.0005). Knockdown of ECT2 expression by small interfering RNAs effectively suppressed lung and esophageal cancer cell growth. In addition, induction of exogenous expression of ECT2 in mammalian cells promoted cellular invasive activity. ECT2 cancer-testis antigen is likely to be a prognostic biomarker in clinic and a potential therapeutic target for the development of anticancer drugs and cancer vaccines for lung and esophageal cancers.

Expression level of ECT2 proto-oncogene correlates with prognosis in glioma patients

The ECT2 (epithelial cell transforming sequence 2) proto-oncogene encodes a guanine nucleotide exchange factor for Rho GTPases, and regulates cytokinesis. ECT2 plays a critical role in Rho activation during cytokinesis, and thus may play a role in the pathogenesis of glioma. In this study, we investigated relationships between ECT2 expression, tumor histology, and prognosis in glioma patients. ECT2 mRNA expression was examined using quantitative real-time PCR, while its protein expression was examined by immunohistochemistry of 54 glioma tissue samples. Expressions of ECT2 mRNA and protein were markedly increased in high-grade gliomas compared to low-grade gliomas. Patients in whom expression of ECT2 mRNA and protein in tumor tissues was the lowest survived longer than patients who had higher expression. In vitro, ECT2 siRNA inhibited glioma cell proliferation and invasion. These data suggest that increased expression of ECT2 contribute to promotion of tumor invasiveness and progression, implying that evaluation of ECT2 expression is a prognostic marker for glioma patients.