The development and progression of gastric cancer involves a number of genetic and epigenetic alterations of tumor suppressor and tumor-related genes. The majority of differentiated carcinomas arise from intestinal me...The development and progression of gastric cancer involves a number of genetic and epigenetic alterations of tumor suppressor and tumor-related genes. The majority of differentiated carcinomas arise from intestinal metaplastic mucosa and exhibit structurally altered tumor suppressor genes, typified by p53, which is inactivated via the classic two-hit mechanism, i.e. loss of heterozygosity （LOH） and mutation of the remaining allele. LOH at certain chromosomal loci accumulates during tumor progression. Approximately 20% of differentiated carcinomas show evidence of mutator pathway tumorigenesis due to hMLH1 inactivation via hypermethylation of promoter CpG islands, and exhibit high-frequency microsatellite instability. In contrast, undifferentiated carcinomas rarely exhibit structurally altered tumor suppressor genes. For instance, while methylation of E-cadherin is often observed in undifferentiated carcinomas, mutation of this gene is generally associated with the progression from differentiated to undifferentiated carcinomas. Hypermethylation of tumor suppressor and tumor-related genes, including APC, CHFR, DAP- kinase, DCC, E-cadherin, GSTP1, hMLH1, p16, PTEN, RASSF1A, RUNX3, and TSLC1, can be detected in both differentiated and undifferentiated carcinomas at varying frequencies. However, the significance of the hypermethylation varies according to the analyzed genomic region, and hypermethylation of these genes can also be present in non-neoplastic gastric epithelia. Promoter demethylation of specific genes, such as MAGE and synudein y, can occur during the progressive stages of both histological types, and is associated with patient prognosis. Thus, while the molecular pathways of gastric carcinogenesis are dependent on histological background, specific genetic alterations can still be used for risk assessment, diagnosis, and prognosis.展开更多
Epithelial-mesenchymal transition (EMT) is a highly conserved process that has been well characterised in embryogenesis. Studies have shown that the aberrant activation of EMT in adult epithelia can promote tumour met...Epithelial-mesenchymal transition (EMT) is a highly conserved process that has been well characterised in embryogenesis. Studies have shown that the aberrant activation of EMT in adult epithelia can promote tumour metastasis by repressing cell adhesion molecules,including epithelial (E)-cadherin. Reduced intracellular adhesion may allow tumour cells to disseminate and spread throughout the body. A number of transcription proteins of the Snail superfamily have been implicated in EMT. These proteins have been shown to be over-expressed in advanced gastrointestinal (GI) tumours including oesophageal adenocarcinomas,colorectal carcinomas,gastric and pancreatic cancers,with a concomitant reduction in the expression of E-cadherin. Regulators of EMT may provide novel clinical targets to detect GI cancers early,so that cancers previously associated with a poor prognosis such as pancreatic cancer can be diagnosed before they become inoperable. Furthermore,pharmacological therapies designed to inhibit these proteins will aim to prevent local and distant tumour invasion.展开更多
AIM: To study the effect of inhibited E-cadherin expression on invasion of cancer cells.METHODS: We designed the nucleotide sequence of siRNA corresponding to 5' non-coding and coding sequence of E-cadherin. 21-nu...AIM: To study the effect of inhibited E-cadherin expression on invasion of cancer cells.METHODS: We designed the nucleotide sequence of siRNA corresponding to 5' non-coding and coding sequence of E-cadherin. 21-nucleotide dssiRNA was synthesized by in vitro transcription with Ambion Silencer TM siRNA Construction Kit. siRNA was transfected into gastric cancer MKN45 using TransMessenger transfection Kit. RT-PCR and immunofluorescent assay were used to investigate the inhibition of the expression of mutated Ecadherin. Invasive ability of cancer cells was determined by Transwell assay.RESULTS: The synthesis of E-cadherin mRNA rather than protein expression was suppressed dramatically 7 d after interference. Decreased protein expression was observed on d 10 after interference. On d 11, invasion ability was enhanced significantly.CONCLUSION: siRNA targeted at non-coding and coding sequence of E-cadherin showed significant inhibition on mRNA and protein expression. Inhibited E-cadherin expression results in increased invasion ability of cancer cells.展开更多
AIM： TO examine the immunoreactivity of E-cadherin and four subtypes of catenin family in human hepatocellular carcinomas （HCCs） and to investigate the correlation between expression of E-cadherin/ catenin complex ...AIM： TO examine the immunoreactivity of E-cadherin and four subtypes of catenin family in human hepatocellular carcinomas （HCCs） and to investigate the correlation between expression of E-cadherin/ catenin complex and clinicopathologic parameters of HCC patients. METHODS： An immunohistochemical study for E-cadherin and catenins was performed on 97 formalin-fixed, paraffin-embedded specimens of HCC. RESULTS： Reduced expression of E-cadherin, ^-, 13-, y-catenin and p120 was observed in 69%, 76%, 63%, 71% and 73%, respectively. Both expressions of E-cadherin and catenin components were significantly correlated with tumor grade （P = 0.000）. It showed significant difference between expression of catenin members and tumor stage （P = 0.003, P = 0.017, P = 0.007 and P = 0.000, respectively）. The reduced expression of E-cadherin in HCCs was significantly correlated with intrahepatic metastasis （IM） and capsular invasion （P = 0.008, P = 0.03, respectively）. A close correlation was also observed between the expression of catenins and the tumor size （P = 0.002, P = 0.034, P = 0.016 and P = 0.000, respectively）. In addition, the expression of each catenin was found correlated with IM （P = 0.012, P = 0.049, P =0.026 and P = 0.014, respectively）. No statistically significant difference was observed between the expression level of E-cadherin/catenin complex and lymph node permission, vascular invasion and satellite nodules. Interestingly, only expression of p120 showed correlation with AFP value （P = 0.035）. The expression of E-cadherin was consistent with α-, β-, γ-catenin and p120 expression （P = 0.000）. Finally, the abnormal expression of E-cadherin/catenin complex was significantly associated with patients＇ survival （P = 0.0253, P = 0.0052, P = 0.003, P = 0.0105 and P = 0.0016, respectively）. Nevertheless, no component of E-cadherin/catenin complex was the independent prognostic factor of HCC patients. CONCLUSION： Down-regulated expressions of E-cadherin, catenins and p120展开更多
Cadherin is an adhesion molecule and a superfamily of calcium-mediated membrane glycoproteins. E-cadherin is the prototype of the class E-cadherin that links to catenins to form the cytoskeleton. Recent evidence has s...Cadherin is an adhesion molecule and a superfamily of calcium-mediated membrane glycoproteins. E-cadherin is the prototype of the class E-cadherin that links to catenins to form the cytoskeleton. Recent evidence has shown that E-cadherin not only acts as an adhesive, but also plays important roles in growth development and carcinogenesis. It has been recently viewed as an invasion as well as a growth suppressor gene. This review summarizes the recent discoveries on E-cadherin and its role in gastric cancer. In particular, our work on E-cadherin in gastric cancer, including its relation with Helicobacter pylori and clinical applications, are described in detail.展开更多
Objective： To investigate the expressions of caveolin-1, E-cadherin and β-catenin in gastric carcinoma, precancerous gastric and chronic non-atrophic gastritis tissues, and evaluate the correlation of these expressi...Objective： To investigate the expressions of caveolin-1, E-cadherin and β-catenin in gastric carcinoma, precancerous gastric and chronic non-atrophic gastritis tissues, and evaluate the correlation of these expressions with the development of gastric cancer. Methods： The expressions of caveolin-1, E-cadherin and β-catenin were detected by biotin-streptavidinperoxidase （SP） immunohistochemistry on 58 gastric cancer tissues, 40 precancerous gastric tissues and 42 chronic non-atrophic gastritis tissues. The correlation between the expressions of caveolin-1, E-cadherin and β-catenin, and the clinicopathologic parameters of gastric cancer was analyzed retrospectively. Results： The positive rates of caveolin-1 and E-cadherin expressions in gastric carcinoma were significantly lower than precancerous gastric and chronic non-atrophic gastritis tissues （P〈0.01）. An abnormal rate of β-catenin expression in gastric carcinoma was higher than precancerous gastric and chronic non-atrophic gastritis tissues （P〈0.01）. Moreover, low expressions of caveolin-1, E-cadherin and β-catenin correlated with tumor size, depth of invasion, lymph node metastasis and TNM stage （P〈0.05）. The positive rates of caveolin-1 and E-cadherin expressions decreased （P〈0.01）, while an abnormal rate of β-catenin expression increased inversely, with the degree of atypical hyperplasia （P〈0.01）. Caveolin-1 expression correlated positively with E-cadherin （r=0.41, P〈0.05）. Caveolin-1 （r=-0.36, P〈0.05） and E-cadherin （r=-0.45, P〈0.05） expressions negatively correlated with abnormal β-catenin expression. Conclusion： These results suggested that dysregulated expressions of caveolin-1, E-cadherin and β-catenin correlated with the development of gastric cancer and its biological behavior.展开更多
Background Peroxisome proliferator activated receptor γ （PPARγ） is a ligand-activated transcription factor. Activation of PPARγ has recently been demonstrated to inhibit various tumor cells growth, progression an...Background Peroxisome proliferator activated receptor γ （PPARγ） is a ligand-activated transcription factor. Activation of PPARγ has recently been demonstrated to inhibit various tumor cells growth, progression and metastasis. E-cadherin-mediated cell adhesion system is now considered to be an “invasion suppressor system” in cancer tissues. Matrix metalloproteinases-2 （MMP-2） is a prerequisite for metastasizing tumor cells. However their correlation is still unknown in gastric carcinoma. The aim of this study was to assess the expression of PPAR7, E-cadherin, MMP-2 and their correlation in gastric carcinoma and metastases. Methods Gastric carcinoma tissues and their corresponding lymph nodes with metastases and the adjacent non-tumor tissues were obtained from 54 patients with gastric cancer who underwent gastrectomy. Expression of PPARγ, E-cadherin and MMP-2 was assessed by immunohistochemical staining. Results The nuclear expression level of PPARγ in neoplastic cells was significantly lower than that in the normal controls （P〈0.001）, with the expression of PPARγ being weaker in primary tumors compared with that in metastases. In all neoplastic cells, E-cadherin was expressed with abnormal patterns （cytoplasm pattern, cytoplasm and membrane pattern or absent）, compared with normal cells where E-cadherin was expressed with a normal pattern （membrane pattern）. Compared with the normal tissues, the expression level of E-cadherin decreased in primary tumors and further decreased in metastases （P〈0.001）. Membrane staining of MMP-2 was detected in the foveolar epithelia of normal gastric mucosa, whereas predominant cytoplasm staining of MMP-2 was found in malignant tissues. The expression of MMP-2 was stronger in metastatic tissues than in primary tumors. In neoplastic foci the expression of PPARγ was negatively correlated with MMP-2 expression （P〈0.05）. However, there was no correlation between E-cadherin and PPARγ or MM P-2 expression. Conclusions Down-regulation of PPAR�展开更多
LRP16 was previously identified as an estrogen-induced gene in breast cancer cells. The responsiveness of LRP16 to estrogen and its functional effects in endometrial cancer （EC） cells are still unclear. Here, we sho...LRP16 was previously identified as an estrogen-induced gene in breast cancer cells. The responsiveness of LRP16 to estrogen and its functional effects in endometrial cancer （EC） cells are still unclear. Here, we show that the mRNA level and promoter activity of the LRP16 gene were significantly increased by 17β-estradiol （E2） in estrogen receptor ot （ERα）-positive Ishikawa human EC cells. Although the growth rate of Ishikawa cells was not obviously affected by ectopic expression of LRP 16, the results of a Transwell assay showed an approximate one-third increase of the invasive capacity ofLRP 16-overexpressing cells. As a result of molecular screening, we observed that the expression of E-cadherin, an essential adhesion molecule associated with tumor metastasis, was repressed by LRP16. Further promoter analyses demonstrated that LRP 16 inhibited E-cadherin transactivation in a dose-dependent manner. However, the inhibition was abolished by estrogen deprivation, indicating that the downregulation of E-cadherin transcription by LRP16 requires ERα mediation. Chromatin immunoprecipitation analyses revealed that the binding of ERα to the E-cadherin promoter was antagonized by LRP 16, suggesting that LRP 16 could interfere with ERα-mediated transcription. These results suggest that the upregulation of LRP 16 by estrogen could be involved in invasive growth by downregulating E-cadherin in human ECs.展开更多
文摘The development and progression of gastric cancer involves a number of genetic and epigenetic alterations of tumor suppressor and tumor-related genes. The majority of differentiated carcinomas arise from intestinal metaplastic mucosa and exhibit structurally altered tumor suppressor genes, typified by p53, which is inactivated via the classic two-hit mechanism, i.e. loss of heterozygosity （LOH） and mutation of the remaining allele. LOH at certain chromosomal loci accumulates during tumor progression. Approximately 20% of differentiated carcinomas show evidence of mutator pathway tumorigenesis due to hMLH1 inactivation via hypermethylation of promoter CpG islands, and exhibit high-frequency microsatellite instability. In contrast, undifferentiated carcinomas rarely exhibit structurally altered tumor suppressor genes. For instance, while methylation of E-cadherin is often observed in undifferentiated carcinomas, mutation of this gene is generally associated with the progression from differentiated to undifferentiated carcinomas. Hypermethylation of tumor suppressor and tumor-related genes, including APC, CHFR, DAP- kinase, DCC, E-cadherin, GSTP1, hMLH1, p16, PTEN, RASSF1A, RUNX3, and TSLC1, can be detected in both differentiated and undifferentiated carcinomas at varying frequencies. However, the significance of the hypermethylation varies according to the analyzed genomic region, and hypermethylation of these genes can also be present in non-neoplastic gastric epithelia. Promoter demethylation of specific genes, such as MAGE and synudein y, can occur during the progressive stages of both histological types, and is associated with patient prognosis. Thus, while the molecular pathways of gastric carcinogenesis are dependent on histological background, specific genetic alterations can still be used for risk assessment, diagnosis, and prognosis.
文摘Epithelial-mesenchymal transition (EMT) is a highly conserved process that has been well characterised in embryogenesis. Studies have shown that the aberrant activation of EMT in adult epithelia can promote tumour metastasis by repressing cell adhesion molecules,including epithelial (E)-cadherin. Reduced intracellular adhesion may allow tumour cells to disseminate and spread throughout the body. A number of transcription proteins of the Snail superfamily have been implicated in EMT. These proteins have been shown to be over-expressed in advanced gastrointestinal (GI) tumours including oesophageal adenocarcinomas,colorectal carcinomas,gastric and pancreatic cancers,with a concomitant reduction in the expression of E-cadherin. Regulators of EMT may provide novel clinical targets to detect GI cancers early,so that cancers previously associated with a poor prognosis such as pancreatic cancer can be diagnosed before they become inoperable. Furthermore,pharmacological therapies designed to inhibit these proteins will aim to prevent local and distant tumour invasion.
基金Supported by the national "973" (national key program on basic research) foundation of China, No. G1998051203
文摘AIM: To study the effect of inhibited E-cadherin expression on invasion of cancer cells.METHODS: We designed the nucleotide sequence of siRNA corresponding to 5' non-coding and coding sequence of E-cadherin. 21-nucleotide dssiRNA was synthesized by in vitro transcription with Ambion Silencer TM siRNA Construction Kit. siRNA was transfected into gastric cancer MKN45 using TransMessenger transfection Kit. RT-PCR and immunofluorescent assay were used to investigate the inhibition of the expression of mutated Ecadherin. Invasive ability of cancer cells was determined by Transwell assay.RESULTS: The synthesis of E-cadherin mRNA rather than protein expression was suppressed dramatically 7 d after interference. Decreased protein expression was observed on d 10 after interference. On d 11, invasion ability was enhanced significantly.CONCLUSION: siRNA targeted at non-coding and coding sequence of E-cadherin showed significant inhibition on mRNA and protein expression. Inhibited E-cadherin expression results in increased invasion ability of cancer cells.
文摘AIM： TO examine the immunoreactivity of E-cadherin and four subtypes of catenin family in human hepatocellular carcinomas （HCCs） and to investigate the correlation between expression of E-cadherin/ catenin complex and clinicopathologic parameters of HCC patients. METHODS： An immunohistochemical study for E-cadherin and catenins was performed on 97 formalin-fixed, paraffin-embedded specimens of HCC. RESULTS： Reduced expression of E-cadherin, ^-, 13-, y-catenin and p120 was observed in 69%, 76%, 63%, 71% and 73%, respectively. Both expressions of E-cadherin and catenin components were significantly correlated with tumor grade （P = 0.000）. It showed significant difference between expression of catenin members and tumor stage （P = 0.003, P = 0.017, P = 0.007 and P = 0.000, respectively）. The reduced expression of E-cadherin in HCCs was significantly correlated with intrahepatic metastasis （IM） and capsular invasion （P = 0.008, P = 0.03, respectively）. A close correlation was also observed between the expression of catenins and the tumor size （P = 0.002, P = 0.034, P = 0.016 and P = 0.000, respectively）. In addition, the expression of each catenin was found correlated with IM （P = 0.012, P = 0.049, P =0.026 and P = 0.014, respectively）. No statistically significant difference was observed between the expression level of E-cadherin/catenin complex and lymph node permission, vascular invasion and satellite nodules. Interestingly, only expression of p120 showed correlation with AFP value （P = 0.035）. The expression of E-cadherin was consistent with α-, β-, γ-catenin and p120 expression （P = 0.000）. Finally, the abnormal expression of E-cadherin/catenin complex was significantly associated with patients＇ survival （P = 0.0253, P = 0.0052, P = 0.003, P = 0.0105 and P = 0.0016, respectively）. Nevertheless, no component of E-cadherin/catenin complex was the independent prognostic factor of HCC patients. CONCLUSION： Down-regulated expressions of E-cadherin, catenins and p120
文摘Cadherin is an adhesion molecule and a superfamily of calcium-mediated membrane glycoproteins. E-cadherin is the prototype of the class E-cadherin that links to catenins to form the cytoskeleton. Recent evidence has shown that E-cadherin not only acts as an adhesive, but also plays important roles in growth development and carcinogenesis. It has been recently viewed as an invasion as well as a growth suppressor gene. This review summarizes the recent discoveries on E-cadherin and its role in gastric cancer. In particular, our work on E-cadherin in gastric cancer, including its relation with Helicobacter pylori and clinical applications, are described in detail.
基金supported by Zhejiang Provincial Natural Science Foundation (No. Y206750)Zhejiang Foundation for Development of Science and Technology, China (No. 2008C33066)Wenzhou Foundation for Development of Science and Technology,China (No. H20060026)
文摘Objective： To investigate the expressions of caveolin-1, E-cadherin and β-catenin in gastric carcinoma, precancerous gastric and chronic non-atrophic gastritis tissues, and evaluate the correlation of these expressions with the development of gastric cancer. Methods： The expressions of caveolin-1, E-cadherin and β-catenin were detected by biotin-streptavidinperoxidase （SP） immunohistochemistry on 58 gastric cancer tissues, 40 precancerous gastric tissues and 42 chronic non-atrophic gastritis tissues. The correlation between the expressions of caveolin-1, E-cadherin and β-catenin, and the clinicopathologic parameters of gastric cancer was analyzed retrospectively. Results： The positive rates of caveolin-1 and E-cadherin expressions in gastric carcinoma were significantly lower than precancerous gastric and chronic non-atrophic gastritis tissues （P〈0.01）. An abnormal rate of β-catenin expression in gastric carcinoma was higher than precancerous gastric and chronic non-atrophic gastritis tissues （P〈0.01）. Moreover, low expressions of caveolin-1, E-cadherin and β-catenin correlated with tumor size, depth of invasion, lymph node metastasis and TNM stage （P〈0.05）. The positive rates of caveolin-1 and E-cadherin expressions decreased （P〈0.01）, while an abnormal rate of β-catenin expression increased inversely, with the degree of atypical hyperplasia （P〈0.01）. Caveolin-1 expression correlated positively with E-cadherin （r=0.41, P〈0.05）. Caveolin-1 （r=-0.36, P〈0.05） and E-cadherin （r=-0.45, P〈0.05） expressions negatively correlated with abnormal β-catenin expression. Conclusion： These results suggested that dysregulated expressions of caveolin-1, E-cadherin and β-catenin correlated with the development of gastric cancer and its biological behavior.
基金the grants from the National Natural Science Foundation of China (No. 30671904 and No. 30670949)the Doctor Subjects Foundation of the Ministry of Education of the People's Republic of China (No. 20060558010).
文摘Background Peroxisome proliferator activated receptor γ （PPARγ） is a ligand-activated transcription factor. Activation of PPARγ has recently been demonstrated to inhibit various tumor cells growth, progression and metastasis. E-cadherin-mediated cell adhesion system is now considered to be an “invasion suppressor system” in cancer tissues. Matrix metalloproteinases-2 （MMP-2） is a prerequisite for metastasizing tumor cells. However their correlation is still unknown in gastric carcinoma. The aim of this study was to assess the expression of PPAR7, E-cadherin, MMP-2 and their correlation in gastric carcinoma and metastases. Methods Gastric carcinoma tissues and their corresponding lymph nodes with metastases and the adjacent non-tumor tissues were obtained from 54 patients with gastric cancer who underwent gastrectomy. Expression of PPARγ, E-cadherin and MMP-2 was assessed by immunohistochemical staining. Results The nuclear expression level of PPARγ in neoplastic cells was significantly lower than that in the normal controls （P〈0.001）, with the expression of PPARγ being weaker in primary tumors compared with that in metastases. In all neoplastic cells, E-cadherin was expressed with abnormal patterns （cytoplasm pattern, cytoplasm and membrane pattern or absent）, compared with normal cells where E-cadherin was expressed with a normal pattern （membrane pattern）. Compared with the normal tissues, the expression level of E-cadherin decreased in primary tumors and further decreased in metastases （P〈0.001）. Membrane staining of MMP-2 was detected in the foveolar epithelia of normal gastric mucosa, whereas predominant cytoplasm staining of MMP-2 was found in malignant tissues. The expression of MMP-2 was stronger in metastatic tissues than in primary tumors. In neoplastic foci the expression of PPARγ was negatively correlated with MMP-2 expression （P〈0.05）. However, there was no correlation between E-cadherin and PPARγ or MM P-2 expression. Conclusions Down-regulation of PPAR�
基金We sincerely thank Dr Pudi Renuka and Dr Jianjun Zhou at the National Cancer Institute for their critical reading of our manuscript. We thank Dr Eric R Fearon at the University of Michigan in USA for the E-cadherin promoter reporters and Dr Nowata at Kyushu University of Japan for the ERα expression vector. This work was supported by the National Natural Science Foundation of China （30471813, 30572096 and 30670809）, the Beijing Natural Science Foundation of China （5052024 and 7052061） and the Chinese PLANational Science Fund for Distinguished Young Scholars grant （06J017）.
文摘LRP16 was previously identified as an estrogen-induced gene in breast cancer cells. The responsiveness of LRP16 to estrogen and its functional effects in endometrial cancer （EC） cells are still unclear. Here, we show that the mRNA level and promoter activity of the LRP16 gene were significantly increased by 17β-estradiol （E2） in estrogen receptor ot （ERα）-positive Ishikawa human EC cells. Although the growth rate of Ishikawa cells was not obviously affected by ectopic expression of LRP 16, the results of a Transwell assay showed an approximate one-third increase of the invasive capacity ofLRP 16-overexpressing cells. As a result of molecular screening, we observed that the expression of E-cadherin, an essential adhesion molecule associated with tumor metastasis, was repressed by LRP16. Further promoter analyses demonstrated that LRP 16 inhibited E-cadherin transactivation in a dose-dependent manner. However, the inhibition was abolished by estrogen deprivation, indicating that the downregulation of E-cadherin transcription by LRP16 requires ERα mediation. Chromatin immunoprecipitation analyses revealed that the binding of ERα to the E-cadherin promoter was antagonized by LRP 16, suggesting that LRP 16 could interfere with ERα-mediated transcription. These results suggest that the upregulation of LRP 16 by estrogen could be involved in invasive growth by downregulating E-cadherin in human ECs.
