Frequent occurrence of abnormal E-cadherin/beta-catenin protein expression in advanced gallbladder cancers and its association with decreased apoptosis

Genetic mutational analysis of β-catenin gene affecting GSK-3β phosphorylation plays a role in gallbladder carcinogenesis: Results from a case control study

This manuscript has reported different mutations of β-catenin gene in gallbladder cancer patients which affect GSK-3β phosphorylation site.

PURPOSE

Gallbladder carcinoma (GBC) is a relatively rare and fatal cancer with poor prognosis. The molecular mechanism of gallbladder carcinogenesis is still not clear. Wnt signaling pathway is a highly conserved pathway that regulates proliferation, differentiation, migration, genetic stability, apoptosis, and stem cell renewal. β-catenin plays major role in Wnt signaling and aberrations in β-catenin has found to be involved in several cancers pathogenesis. This study was carried out to document the mutations of β-catenin gene in gallbladder cancer and to evaluate its possible role in gallbladder carcinogenesis.

METHODS

PCR-SSCP (Single Stranded Conformation Polymorphism) for ctnnb1 was performed in 50 patients each of gallbladder cancer, cholelithiasis and 50 healthy controls. Samples that showed variation in banding pattern were sequenced.

RESULTS

Variation in banding pattern was observed in 9 (18%) samples of GBC, 4 (8%) of cholelithiasis and 2 (4%) of control. Sequencing analysis showed 9 novel mutations of ctnnb1 in exon 3 in 18% of gallbladder cancer (χ2 = 5.778; p < 0.05). Six point mutations, 1 deletion and 1 insertion mutation were found in 9 cases of gallbladder cancer. All point mutations were mis-sense mutation that affected highly conserved serine or threonine region that is important for GSK-3β phosphorylation.

CONCLUSION

Findings of the study suggests that high frequency of non synonymous mutations of β-catenin gene (ctnnb1) occurs in patients with gallbladder cancer. As these mutations mainly effect GSK 3β phosphorylation, it may be concluded that this might be an important step in gallbladder carcinogenesis. These β-catenin mutations lead to Wnt pathway activation and appear to have a role in progression from inflammation to cancer in gallbladder.

Molecular pathogenesis of gallbladder cancer: An update

Gallbladder carcinoma (GBC) is the most aggressive gastrointestinal malignancy throughout the world, with wide geographical variance. It is the subtype of biliary tract malignancy that has the poorest prognosis and lower survival among all biliary tract malignancies. Various factors are associated with GBC pathogenesis such as environmental, microbial, metabolic and molecular. Chronic inflammation of gallbladder due to presence of gallstone or microbial infection (eg. Salmonella or H. pylori) results in sustained production of inflammatory mediators in the tissue microenvironment, which can cause genomic changes linked to carcinogenesis. Genetic alterations are one of the major factors, associated with aggressiveness and prognosis. Researches have been done to explore suitable biomarker for early diagnosis and identify altered molecular pathways to develop appropriate biomarkers for early diagnosis, therapy and predicting prognosis. Different agents for targeted therapy against actionable mutations of molecules like EGFR, VEGF, mTOR, HER2, PDL-1, PD-1, MET, PI3K, N-cadherin, VEGFR, MEK1 and MEK2 are being tried. Despite these advancements, there is dismal improvement in the survival of GBC patients. Genetic aberrations other than actionable mutations and epigenetic modification including aberrant expressions of micro-RNAs, are also being studied both as diagnostic biomarker and therapeutic targets. Complex pathogenesis of GBC still needs to be unfolded. In this review we focus on the molecular pathogenesis of GBC elucidated till date along with future directions that can be explored to achieve better management of GBC patients.

Epithelial-to-mesenchymal transition in gallbladder cancer: from clinical evidence to cellular regulatory networks

Gallbladder cancer (GBC), with late diagnosis, rapid disease progression and early metastasis, is a highly aggressive malignant tumor found worldwide. Patients with GBC have poor survival, low curative resection rates and early recurrence. For such a lethal tumor, uncovering the mechanisms and exploring new strategies to prevent tumor progression and metastasis are critically important. Epithelial-to-mesenchymal transition (EMT) has a prominent role in the early steps of tumor progression and metastasis by initiating polarized epithelial cell transition into motile mesenchymal cells. Accumulating evidence suggests that EMT can be modulated by the cooperation of multiple mechanisms affecting common targets. Signaling pathways, transcriptional and post-transcriptional regulation and epigenetic alterations are involved in the stepwise EMT regulatory network in GBC. Loss of epithelial markers, acquisition of mesenchymal markers and dysregulation of EMT-inducing transcription factors (EMT-TFs) have been observed and are associated with the clinicopathology and prognosis of GBC patients. Therefore, EMT may be a detectable and predictable event for predicting GBC progression and metastasis in the clinic. In this review, we will provide an overview of EMT from the clinical evidence to cellular regulatory networks that have been studied thus far in clinical and basic GBC studies.

New Horizons for Precision Medicine in Biliary Tract Cancers

Biliary tract cancers (BTC), including cholangiocarcinoma and gallbladder cancer, are poor-prognosis and low-incidence cancers, although the incidence of intrahepatic cholangiocarcinoma is rising. A minority of patients present with resectable disease but relapse rates are high; benefit from adjuvant capecitabine chemotherapy has been demonstrated. Cisplatin/gemcitabine combination chemotherapy has emerged as the reference first-line treatment regimen; there is no standard second-line therapy. Selected patients may be suitable for liver-directed therapy (e.g., radioembolization or external beam radiation), pending confirmation of benefit in randomized studies. Initial trials targeting the epithelial growth factor receptor and angiogenesis pathways have failed to deliver new treatments. Emerging data from next-generation sequencing analyses have identified actionable mutations (e.g., FGFR fusion rearrangements and IDH1 and IDH2 mutations), with several targeted drugs entering clinical development with encouraging results. The role of systemic therapies, including targeted therapies and immunotherapy for BTC, is rapidly evolving and is the subject of this review.Significance: The authors address genetic drivers and molecular biology from a translational perspective, in an intent to offer a clear view of the recent past, present, and future of BTC. The review describes a state-of-the-art update of the current status and future directions of research and therapy in advanced BTC. Cancer Discov; 7(9); 943-62. ©2017 AACR.

New Horizons for Precision Medicine in Biliary Tract Cancers

Biliary tract cancers (BTC), including cholangiocarcinoma and gallbladder cancer, are poor-prognosis and low-incidence cancers, although the incidence of intrahepatic cholangiocarcinoma is rising. A minority of patients present with resectable disease but relapse rates are high; benefit from adjuvant capecitabine chemotherapy has been demonstrated. Cisplatin/gemcitabine combination chemotherapy has emerged as the reference first-line treatment regimen; there is no standard second-line therapy. Selected patients may be suitable for liver-directed therapy (e.g., radioembolization or external beam radiation), pending confirmation of benefit in randomized studies. Initial trials targeting the epithelial growth factor receptor and angiogenesis pathways have failed to deliver new treatments. Emerging data from next-generation sequencing analyses have identified actionable mutations (e.g., FGFR fusion rearrangements and IDH1 and IDH2 mutations), with several targeted drugs entering clinical development with encouraging results. The role of systemic therapies, including targeted therapies and immunotherapy for BTC, is rapidly evolving and is the subject of this review.Significance: The authors address genetic drivers and molecular biology from a translational perspective, in an intent to offer a clear view of the recent past, present, and future of BTC. The review describes a state-of-the-art update of the current status and future directions of research and therapy in advanced BTC. Cancer Discov; 7(9); 943-62. ©2017 AACR.

Effects of HMGA2 siRNA and doxorubicin dual delivery by chitosan nanoparticles on cytotoxicity and gene expression of HT-29 colorectal cancer cell line

Objective

Over-expressions of HMGA2, vimentin and MMP-9 and downregulation of E-cadherin occur on colorectal cancer cells followed by a reduction in let-7 as a regulatory factor. In this study, we first used carboxymethyl dextran (CMD)–chitosan nanoparticles (ChNPs) platform to encapsulate HMGA2 siRNA and doxorubicin (DOX), and then, we evaluated the efficacy of the simultaneous delivery of siRNA/drug on viability and gene expression of HT-29 cell lines.

Methods

ChNPs characteristics were determined by a dynamic light scattering and zeta sizer. Morphology of loaded ChNPs was assessed by scanning electron microscopy, and Fourier transform infrared spectroscopy was used to confirm the conjugation of ChNP/siRNA/DOX/CMD. Cell viability and relative mRNA expression were evaluated by MTT assay and real-time PCR, respectively.

Key finding

The prepared ChNPs had high efficiency for siRNA and drug encapsulation (78% and 75%) and were stable against serum and heparin. ChNP/siRNA/DOX/CMD was more effective to induce tumour cell death and also could significantly reduce the expressions of HMGA2, vimentin as well as MMP-9 and increase E-cadherin expression.

Conclusion

In conclusion, our results revealed that dual delivery of a key gene siRNA and appropriate anticancer drug have great impact on the treatment of colorectal cancer.

Macrophage migration inhibitory factor - a therapeutic target in gallbladder cancer

Background

Poor prognosis in gallbladder cancer is due to late presentation of the disease, lack of reliable biomarkers for early diagnosis and limited targeted therapies. Early diagnostic markers and novel therapeutic targets can significantly improve clinical management of gallbladder cancer.

Methods

Proteomic analysis of four gallbladder cancer cell lines based on the invasive property (non-invasive to highly invasive) was carried out using the isobaric tags for relative and absolute quantitation labeling-based quantitative proteomic approach. The expression of macrophage migration inhibitory factor was analysed in gallbladder adenocarcinoma tissues using immunohistochemistry. In vitro cellular assays were carried out in a panel of gallbladder cancer cell lines using MIF inhibitors, ISO-1 and 4-IPP or its specific siRNA.

Results

The quantitative proteomic experiment led to the identification of 3,653 proteins, among which 654 were found to be overexpressed and 387 were downregulated in the invasive cell lines (OCUG-1, NOZ and GB-d1) compared to the non-invasive cell line, TGBC24TKB. Among these, macrophage migration inhibitory factor (MIF) was observed to be highly overexpressed in two of the invasive cell lines. MIF is a pleiotropic proinflammatory cytokine that plays a causative role in multiple diseases, including cancer. MIF has been reported to play a central role in tumor cell proliferation and invasion in several cancers. Immunohistochemical labeling of tumor tissue microarrays for MIF expression revealed that it was overexpressed in 21 of 29 gallbladder adenocarcinoma cases. Silencing/inhibition of MIF using siRNA and/or MIF antagonists resulted in a significant decrease in cell viability, colony forming ability and invasive property of the gallbladder cancer cells.

Conclusions

Our findings support the role of MIF in tumor aggressiveness and suggest its potential application as a therapeutic target for gallbladder cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1855-z) contains supplementary material, which is available to authorized users.

Prognostic molecular markers in resected extrahepatic biliary tract cancers; a systematic review and meta-analysis of immunohistochemically detected biomarkers

Better prognostic information for resected extrahepatic cholangiocarcinoma could guide treatment strategies and potentially improve outcome. This study performed a systematic review and meta-analysis to identify prognostic biomarkers for further investigation.

METHODS

Relevant literature was identified using Medline, EMBASE and Web of Science. Primary end point was overall survival assessed on univariate analysis. Log hazard ratio and variance were calculated and pooled using a random effects inverse variance approach. Hazard ratio and 95% confidence intervals were calculated.

RESULTS

Thirty-seven studies, including 2371 patients, met the inclusion criteria. Subsequently nine biomarkers predictive of OS were identified (HR, 95% CI): VEGF (2.32, 1.57-3.44), COX-2 (1.94, 1.01-3.71), GLUT-1 (2.09, 1.52-2.89), Cyclin D1 (1.96, 1.02-3.76), p16 (0.68, 0.47-0.98), p27 (0.48, 0.3-0.78), E-Cadherin (0.47, 0.35-0.63), Fascin (2.19, 1.35-3.55), and Ki-67 (1.69, 1.02-2.79).

CONCLUSION

Meta-analysis has identified a number of prognostic biomarkers for resected extrahepatic cholangiocarcinoma. These markers warrant further investigation as potential therapeutic targets and validation in a prospective setting.

Decreased expression and prognostic role of EHD2 in human breast carcinoma: correlation with E-cadherin

Decreased expression of epithelial cadherin (E-cadherin) has been noted to associate with aggressiveness and metastasis of breast cancer. The aim of this study was to examine the effect of C-Terminal EH domain-containing protein 2 (EHD2) expression on E-cadherin and related mechanism in the metastasis of breast cancer. Immunohistochemical analysis was performed in 96 human breast carcinoma samples and the data were correlated with clinicopathologic characteristics. Furthermore, Western blot analysis was performed for EHD2 and E-cadherin in breast carcinoma samples and cell lines to evaluate their protein levels and molecular interaction. We found that the expression of EHD2 was positively related with E-cadherin expression (P < 0.01), moreover, EHD2 expression was significantly correlated with histologic grade (P < 0.01). Meanwhile, E-cadherin expression obtained similar results. Kaplan-Meier survival analysis showed that decreased expression of EHD2 and E-cadherin exhibited a significant correlation with poor prognosis in human breast cancer (P < 0.01). While in vitro, we employed siRNA technique to knock down EHD2 expressions and observed their effects on breast cancer cells growth. EHD2 depletion by siRNA promoted PCNA expression, and it was concurrent with the decreased expression of epithelial marker E-cadherin and the increased expression of N-cadherin by Western blot analysis. Consistent with these observations, the suppression of EHD2 in breast cancer cells remarkably promoted cellular proliferation and migration. On the basis of these results, we suggested that EHD2 can inhibit the metastasis of human breast cancer by regulating the EMT key markers E-cadherin and N-cadherin.

Clinical significance of expression of p53 and β-catenin in gallbladder carcinoma

AIM: To examine the expression of p53 and β-catenin in gallbladder carcinoma and to analyze their significance.

METHODS: The expression of p53 and β-catenin in 58 gallbladder carcinoma specimens, 10 adenomatous polyp specimens and 20 chronic cholecystitis specimens was detected by immunohistochemistry.

RESULTS: The positive expression rates of p53 and β-catenin in gallbladder carcinoma (62.07%, 68.97%) were significantly higher than those in adenomatous polyps (33.33%, 40.00%) and chronic cholecystitis (10.00%, 5.00%) (P < 0.05). There was no significant correlation between the expression of p53 and that of β-catenin in gallbladder carcinoma (P > 0.05). The positive expression rates of p53 and β-catenin were lower in well differentiated than in moderately and lowly differentiated gallbladder carcinoma tissues, but lower in early stage (Nevin Ⅰ-Ⅲ) than in advanced stage (Nevin Ⅳ-Ⅴ) and in cases without lymph node metastasis or invasion of the surrounding tissues than in those with (P < 0.05).

CONCLUSION: The overexpression of p53 and β-catenin may be closely related to the initiation and biological behavior of gallbladder carcinoma.

p53 and beta-catenin expression in gallbladder tissues and correlation with tumor progression in gallbladder cancer

BACKGROUND/AIM

The inactivation of the tumor suppressor gene and activation of the proto-oncogene are key steps in the development of human cancer. p53 and beta-catenin are examples of such genes, respectively. In the present study, our aim was to determine the role of these genes in the carcinogenesis of the gallbladder by immunohistochemistry.

PATIENTS AND METHODS

Sections from paraffin-embedded blocks of surgically resected specimens of gallbladder cancer (GBC) (80 cases), chronic cholecystitis (60 cases), and control gallbladders (10 cases) were stained with the monoclonal antibody p53, and polyclonal antibody beta-catenin. Results were scored semiquantitatively and statistical analysis performed. p53 expression was scored as percentage of the nuclei stained. Beta-catenin expression was scored as type of expression-membranous, cytoplasmic, and nuclear staining. Beta-catenin expression was correlated with tumor invasiveness, differentiation, and stage.

RESULTS

Over-expression of p53 was seen in 56.25% of GBC cases and was not seen in chronic cholecystitis or in control gallbladders. p53 expression in gallbladder cancer was significantly higher than in inflammatory or control gallbladders (P < 0.0001). p53 expression increased with increasing tumor grade (P = 0.039). Beta-catenin nuclear expression was seen in 75% cases of gallbladder cancer and in no case of chronic cholecystitis and control gallbladder. Beta-catenin nuclear expression increased with tumor depth invasiveness, and grade (P = 0.028 and P = 0.0152, respectively).

CONCLUSION

p53 and beta-catenin nuclear expression is significantly higher in GBC. p53 expression correlates with increasing tumor grade while beta-catenin nuclear expression correlates with tumor grade and depth of invasion, thus suggesting a role for these genes in tumor progression of GBC.

Molecular biology of gallbladder cancer: potential clinical implications

Gallbladder cancer (GBC) is a common malignancy of the biliary tract and involves the changes in multiple oncogenes and multiple genetic genes. Since over the past decade there has been an advance in the knowledge of the genetic basis of cancer, mainly as a result of the rapid progression of molecular technology; however, conventional therapeutic approaches have not had much impact on the course of this aggressive neoplasm. Knowledge of the molecular biology of GBC is rapidly growing. Genetic alterations in GBC include adenosine triphosphate-binding cassette transporter ABCG8, membrane-bound enzyme ADAM-17 of multi-functional gene family, and other genes including p53, COX2, XPC, and RASSF1A. The advances in molecular biology have potential implications for the detection of this disease, using Synuclein-gamma, Syndecan-1, glycoprotein 72 (TAG-72), tumor endothelial marker 8 protein (TEM8) and TNF-alpha. The use of these molecular diagnostic methods is of clinical importance for the gene replacement therapy, genetic prodrug activation therapy, and antisense immunology technology for the treatment of malignancy. The author reviewed recent publications on PubMed, and summarized molecular biology of GBC, with an emphasis on features of potential clinical implications for diagnosis and management.

DNA promoter methylation as a diagnostic and therapeutic biomarker in gallbladder cancer

Gallbladder cancer is an infrequent neoplasia with noticeable geographical variations in its incidence around the world. In Chile, it is the main cause of death owing to cancer in women over 40 years old, with mortality rates up to 16.5 per 100,000 cases. The prognosis is poor with few therapeutic options; in advanced cases there is only a 10% survival at 5 years.

Several studies mention the possible role of DNA methylation in gallbladder carcinogenesis. This epigenetic modification affects tumor suppressor genes involved in regulation pathways, cell cycle control, cell adhesion and extracellular matrix degradation, in a sequential and cumulative way. Determining DNA methylation patterns would allow them to be used as biomarkers for the early detection, diagnosis, prognosis and/or therapeutic selection in gallbladder cancer.

Significance of epithelial growth factor in the epithelial-mesenchymal transition of human gallbladder cancer cells

Five gallbladder cancer (GBC) cell lines were examined for morphological changes in collagen gel culture. GBh3 and HUCCT-1 cells formed tubules in response to treatment with epithelial growth factor (EGF) and hepatocyte growth factor (HGF), and showed high levels of expression of E-cadherin (ECD), and low levels of SNAIL, vimentin, transforming growth factor (TGF)-β, and nucleostemin (NS). In contrast, the GBd15 and FU-GBC-1 cell lines treated with EGF and HGF showed a scattering phenotype, and expressed low levels of ECD and high levels of SNAIL, vimentin, TGF-β, and NS. All cell lines expressed the EGF receptor, c-Met, EGF, and TGF-α, but not HGF. Transforming growth factor-β was upregulated by EGF. Knockdown of the EGF receptor abrogated both tubule formation and scattering, whereas KD of TGF-β abrogated only scattering. Knockdown of EGF induced nuclear translocation of β-catenin and Wnt-related NS induction in the scattering cell lines, but not in the tubule-forming cell lines, whereas KD of glycogen synthase kinase-3β in the tubule-forming cell lines resulted in the nuclear translocation of β-catenin and Wnt-related NS induction in response to EGF treatment. These results suggest that EGF enhances epithelial-mesenchymal transformation and acquisition of stemness in GBC cells with a scattering phenotype through the activity of β-catenin. Repression of ECD in scattering GBC cells induced the release of β-catenin from the cell adhesion complexes along the plasma membrane and its translocation to the nucleus to activate Wnt signaling, which upregulated NS.

Loss of E-cadherin promotes the growth, invasion and drug resistance of colorectal cancer cells and is associated with liver metastasis

The recent studies indicated that the epithelial cell adhesion molecule E-cadherin is a well-recognized molecule that is important in cell adhesion. To further investigate the molecular basis of this notion, we used small-interfering RNA to inhibit E-cadherin function and found that loss of E-cadherin promoted Colorectal cancer cell growth, invasion and drug resistance through induction of β-catenin nuclear translocation and epithelial-to-mesenchymal transition. Further analysis of E-cadherin expression with clinicopathologic parameters showed that E-cadherin expression decreased in Colorectal cancer patients who developed liver metastasis (P = 0.043). These findings indicate that E-cadherin loss in tumors contributes to progression and metastatic dissemination. Thus, E-cadherin can act as a central modulator of the cell biological phenotypes and a potential prognostic marker in Colorectal cancer.

The relevance and role of vascular endothelial growth factor C, matrix metalloproteinase-2 and E-cadherin in epithelial ovarian cancer

We investigated the correlation of vascular endothelial growth factor C, matrix metalloproteinase-2, E-cadherin to explore mechanisms of vascular endothelial growth factor C in the metastasis of ovarian cancer and the relationship of prognosis. We applied immunohistochemistry to investigate the expression of vascular endothelial growth factor C, matrix metalloproteinase-2 and E-cadherin in ovarian tissues of 227 patients. We adopted Pearson chi-square test, Spearman correlation coefficient, univariate analysis, multivariate analysis, and Kaplan-Meier method. The positive rate of vascular endothelial growth factor C, matrix metalloproteinase-2 and E-cadherin in ovarian cancer was higher than that in borderline and benign tumor (P < 0.01). Vascular endothelial growth factor C was positively correlated with matrix metalloproteinase-2 (r = 0.665, P < 0.01) while negatively with E-cadherin(r = -0.185, P < 0.05). Univariate analysis showed clinical stage, pathologic grade, lymphatic metastasis, residual disease, chemotherapy, ascites, vascular endothelial growth factor C, and matrix metalloproteinase-2-influenced survival time (P < 0.05). In Cox multivariate analysis, all the aforementioned factors were found to be independent prognostic factors except pathologic grade. Vascular endothelial growth factor C was a new target to assess the prognosis of ovarian cancer. The expression of vascular endothelial growth factor C in ovarian cancer was related to matrix metalloproteinase-2 and E-cadherin.

Estrogen-dependent gallbladder carcinogenesis in LXRbeta-/- female mice

Gallbladder cancer is a highly aggressive disease with poor prognosis that is two to six times more frequent in women than men. The development of gallbladder cancer occurs over a long time (more than 15 y) and evolves from chronic inflammation to dysplasia/metaplasia, carcinoma in situ, and invasive carcinoma. In the present study we found that, in female mice in which the oxysterol receptor liver X receptor-beta (LXRbeta) has been inactivated, preneoplastic lesions of the gallbladder developed and evolved to cancer in old animals. LXRbeta is a nuclear receptor involved in the control of lipid homeostasis, glucose metabolism, inflammation, proliferation, and CNS development. LXRbeta(-/-) female gallbladders were severely inflamed, with regions of dysplasia and high cell density, hyperchromasia, metaplasia, and adenomas. No abnormalities were evident in male mice, nor in LXRalpha(-/-) or LXRalpha(-/-)beta(-/-) animals of either sex. Interestingly, the elimination of estrogens with ovariectomy prevented development of preneoplastic lesions in LXRbeta(-/-) mice. The etiopathological mechanism seems to involve TGF-beta signaling, as the precancerous lesions were characterized by strong nuclear reactivity of phospho-SMAD-2 and SMAD-4 and loss of E-cadherin expression. Upon ovariectomy, E-cadherin was reexpressed on the cell membranes and immunoreactivity of pSMAD-2 in the nuclei was reduced. These findings suggest that LXRbeta in a complex interplay with estrogens and TGF-beta could play a crucial role in the malignant transformation of the gallbladder epithelium.

Zonula occludens-1, occludin, and E-cadherin protein expression in biliary tract cancers

The incidence of cholangiocarcinomas originating from intrahepatic and extrahepatic bile ducts, as well as of gallbladder carcinoma is increasing worldwide. The malignant transformation of biliary epithelia involves profound alterations of proteins in the intercellular junctions, among others zonula occludens-1 (ZO-1), occludin, and E-cadherin. Each plays important role in the maintenance of epithelial cell polarity and regulation of cell growth and differentiation. Our aim was to investigate ZO-1, occludin, and E-cadherin immunohistochemical reactions in tissue microarray blocks containing 57 normal and 62 neoplastic biliary tract samples. We demonstrated that the tight junction components ZO-1, occludin, and E-cadherin are downregulated in carcinomas arising from various compartments of the biliary tract (normal intrahepatic and extrahepatic bile ducts, gallbladder) as compared with their normal sites of origin. These results were confirmed by discriminant analysis yielding clear separation of the three normal sample groups from carcinomas in the corresponding locations.

Molecular targets and biological modifiers in gastric cancer

The overall survival of gastric cancer patients remains poor despite efforts and advances in its prevention, diagnosis, and treatment. The development of new therapies is crucial for the effective control of this disease. An increasing number of genetic and epigenetic alterations have been associated with distinct histological types of gastric cancer. In this review, we will discuss the involvement of E-cadherin, EGFR, ERBB2, MMR genes, KRAS, and PIK3CA in the development and progression of gastric cancer and their role as biomarkers or as novel putative targets for therapy.

Estrogen regulates Snail and Slug in the down-regulation of E-cadherin and induces metastatic potential of ovarian cancer cells through estrogen receptor alpha

Tumorigenesis is a multistep process involving dysregulated cell growth and metastasis. Considerable evidence implicates a mitogenic action of estrogen in early ovarian carcinogenesis. In contrast, its influence in the metastatic cascade of ovarian tumor cells remains obscure. In the present study, we showed that 17beta-estradiol (E2) increased the metastatic potential of human epithelial ovarian cancer cell lines. E2 treatment led to clear morphological changes characteristic of epithelial-mesenchymal transition (EMT) and an enhanced cell migratory propensity. These morphological and functional alterations were associated with changes in the abundance of EMT-related genes. Upon E2 stimulation, expression and promoter activity of the epithelial marker E-cadherin were strikingly suppressed, whereas EMT-associated transcription factors, Snail and Slug, were significantly up-regulated. This up-regulation was attributed to the increase in gene transcription activated by E2. Depletion of endogenous Snail or Slug using small interfering RNA (siRNA) attenuated E2-mediated decrease in E-cadherin. In addition, E2-induced cell migration was also neutralized by the siRNAs, suggesting that both transcription factors are indispensable for the prometastatic actions of E2. More importantly, by using selective estrogen receptor (ER) agonists, forced expression, and siRNA approaches, we identified that E2 triggered the metastatic behaviors exclusively through an ERalpha-dependent pathway. We also showed that ERbeta had an opposing action on ERalpha because the presence of ERbeta completely inhibited the EMT and down-regulation of E-cadherin induced by ERalpha. Collectively, this study provides a compelling argument that estrogen can potentiate tumor progression by EMT induction and highlights the crucial role of ERalpha in ovarian tumorigenesis.

beta(2)microglobulin mRNA expression levels are prognostic for lymph node metastasis in colorectal cancer patients

Colorectal cancer (CRC) is the fourth most common non-cutaneous malignancy in the United States and the second most frequent cause of cancer-related death. One of the most important determinants of CRC survival is lymph node metastasis. To determine whether molecular markers might be prognostic for lymph node metastases, we measured by quantitative real-time RT–PCR the expression levels of 15 cancer-associated genes in formalin-fixed paraffin-embedded primary tissues derived from stage I–IV CRC patients with (n=20) and without (n=18) nodal metastases. Using the mean of the 15 genes as an internal reference control, we observed that low expression of β₂microglobulin (B2M) was a strong prognostic indicator of lymph node metastases (area under the curve (AUC)=0.85; 95% confidence interval (CI)=0.69–0.94). We also observed that the expression ratio of B2M/Spint2 had the highest prognostic accuracy (AUC=0.87; 95% CI=0.71–0.96) of all potential two-gene combinations. Expression values of Spint2 correlated with the mean of the entire gene set at an R² value of 0.97, providing evidence that Spint2 serves not as an independent prognostic gene, but rather as a reliable reference control gene. These studies are the first to demonstrate a prognostic role of B2M at the mRNA level and suggest that low B2M expression levels might be useful for identifying patients with lymph node metastasis and/or poor survival.

Tumor suppressor gene insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) induces senescence-like growth arrest in colorectal cancer cells

Insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) is a potential tumor suppressor gene. This study attempted to explore a potential senescence-like role for IGFBP-rP1 in suppressing human colorectal cancer. Recombinant IGFBP-rP1 inhibited cell proliferation and induced G1 cell cycle arrest in RKO and CW2 cells. It induced a senescence-like phenotype by showing 2-fold higher beta-galactosidase activity in IGFBP-rP1-transfectants over that in control cells. Western blot confirmed down-regulation of phosphorylated retinoblastoma protein (pRB) and up-regulation of p53 in IGFBP-rP1-transfectants as compared with control cells. Thus, IGFBP-rP1 might be a key molecule in the cellular senescence pathway. Our results uncovered a novel molecular mechanism involving the altered expression of pRB and p53 for tumor suppressor gene IGFBP-rP1 in colorectal cancer. Restoration of IGFBP-rP1 function might have potential therapeutic significance in colorectal cancer.