Role of E-cadherin gene in gall bladder cancer and its precursor lesions

Gallbladder cancer: Progress in the Indian subcontinent

Gallbladder cancer (GBC) is one of the commonest biliary malignancies seen in India, Argentina, and Japan. The disease has dismal outcome as it is detected quite late due to nonspecific symptoms and signs. Early detection is the only way to improve the outcome. There have been several advances in basic as well as clinical research in the hepatobiliary and pancreatic diseases in the West and other developed countries but not enough has been done in GBC. Therefore, it is important and the responsibility of the countries with high burden of GBC to find solutions to the many unanswered questions like etiopathogenesis, early diagnosis, treatment, and prognostication. As India being one of the largest hubs for GBC in the world, it is important to know how the country has progressed on GBC. In this review, we will discuss the outcome of the publications from India highlighting the work and the developments taken place in past several decades both in basic and clinical research.

Gallbladder cancer

Gallbladder cancer (GBC) is the most common cancer of the biliary tract, characterized by a very poor prognosis when diagnosed at advanced stages owing to its aggressive behaviour and limited therapeutic options. Early detection at a curable stage remains challenging because patients rarely exhibit symptoms; indeed, most GBCs are discovered incidentally following cholecystectomy for symptomatic gallbladder stones. Long-standing chronic inflammation is an important driver of GBC, regardless of the lithiasic or non-lithiasic origin. Advances in omics technologies have provided a deeper understanding of GBC pathogenesis, uncovering mechanisms associated with inflammation-driven tumour initiation and progression. Surgical resection is the only treatment with curative intent for GBC but very few cases are suitable for resection and most adjuvant therapy has a very low response rate. Several unmet clinical needs require to be addressed to improve GBC management, including discovery and validation of reliable biomarkers for screening, therapy selection and prognosis. Standardization of preneoplastic and neoplastic lesion nomenclature, as well as surgical specimen processing and sampling, now provides reproducible and comparable research data that provide a basis for identifying and implementing early detection strategies and improving drug discovery. Advances in the understanding of next-generation sequencing, multidisciplinary care for GBC, neoadjuvant and adjuvant strategies, and novel systemic therapies including chemotherapy and immunotherapies are gradually changing the treatment paradigm and prognosis of this recalcitrant cancer.

Are We Benign? What Can Wnt Signaling Pathway and Epithelial to Mesenchymal Transition Tell Us about Intracranial Meningioma Progression

Epithelial to mesenchymal transition (EMT), which is characterized by the reduced expression of E-cadherin and increased expression of N-cadherin, plays an important role in the tumor invasion and metastasis. Classical Wnt signaling pathway has a tight link with EMT and it has been shown that nuclear translocation of β-catenin can induce EMT. This research has showed that genes that are involved in cadherin switch, CDH1 and CDH2, play a role in meningioma progression. Increased N-cadherin expression in relation to E-cadherin was recorded. In meningioma, transcription factors SNAIL, SLUG, and TWIST1 demonstrated strong expression in relation to E- and N-cadherin. The expression of SNAIL and SLUG was significantly associated with higher grades (p = 0.001), indicating their role in meningioma progression. Higher grades also recorded an increased expression of total β-catenin followed by an increased expression of its active form (p = 0.000). This research brings the results of genetic and protein analyzes of important molecules that are involved in Wnt and EMT signaling pathways and reveals their role in intracranial meningioma. The results of this study offer guidelines and new markers of progression for future research and reveal new molecular targets of therapeutic interventions.

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.

Gallbladder cancer epidemiology, pathogenesis and molecular genetics: Recent update

Gallbladder cancer is a malignancy of biliary tract which is infrequent in developed countries but common in some specific geographical regions of developing countries. Late diagnosis and deprived prognosis are major problems for treatment of gallbladder carcinoma. The dramatic associations of this orphan cancer with various genetic and environmental factors are responsible for its poorly defined pathogenesis. An understanding to the relationship between epidemiology, molecular genetics and pathogenesis of gallbladder cancer can add new insights to its undetermined pathophysiology. Present review article provides a recent update regarding epidemiology, pathogenesis, and molecular genetics of gallbladder cancer. We systematically reviewed published literature on gallbladder cancer from online search engine PubMed (http://www.ncbi.nlm.nih.gov/pubmed). Various keywords used for retrieval of articles were Gallbladder, cancer Epidemiology, molecular genetics and bullion operators like AND, OR, NOT. Cross references were manually searched from various online search engines (http://www.ncbi.nlm.nih.gov/pubmed,https://scholar.google.co.in/, http://www.medline.com/home.jsp). Most of the articles published from 1982 to 2015 in peer reviewed journals have been included in this review.

Inverse correlation between CD8+ inflammatory cells and E-cadherin expression in gallbladder cancer: Tissue microarray and imaging analysis

AIM

To investigated the association between the tumor cells’ expression of E-cadherin and the numbers of several types of inflammatory cells infiltrating into the invasive portion of gallbladder cancer (GBC).

METHODS

We analyzed 50 GBC cases for which a sufficient amount of tumor tissues for tissue microarray (TMA) had been saved. Three tissue cores (3.0 mm) of invasive lesion from each case were used for the TMA. The 4-μm cut sections on slides were immunostained using primary antibodies including E-cadherin for cancer cells, leukocyte common antigen for leukocyte, myeloperoxidase for neutrophils, CD3 for T cells, CD4 for helper T cells, CD8 for killer T cells, CD20 for B cells and CD68 for macrophages. The immunostained slides were digitally analyzed by imaging analysis software.

RESULTS

A significant inverse correlation between the number of infiltrating CD8⁺ cells at invasive areas and the expression of E-cadherin by cancer cells was observed (P = 0.0001), although the degree of this correlation was relatively weak (R = 0.32). The number of CD8⁺ cells and the cancer cells’ E-cadherin expression were also significantly correlated with tumor differentiation (well-differentiated vs poorly differentiated) (P = 0.0467 and P = 0.0294, respectively). Inverse correlation of T-stage and the number of CD8⁺ cell infiltration was observed with statistical significance in comparison of T2 and T3 cases (P = 0.0324).

CONCLUSION

Our findings indicate an inverse correlation of CD8⁺ T cell infiltration and cancer cells’ E-cadherin expression at invasive areas of GBC. Further analyses are essential to test these findings.

Sequential occurrence of preneoplastic lesions and accumulation of loss of heterozygosity in patients with gallbladder stones suggest causal association with gallbladder cancer

BACKGROUND

Causal association of gallbladder stones with gallbladder cancer (GBC) is not yet well established.

OBJECTIVE

To study the frequency of occurrence of preneoplastic histological lesions and loss of heterozygosity (LOH) of tumor suppressor genes in patients with gallstones.

METHODS

All consecutive patients with gallstones undergoing cholecystectomy from 2007-2011 were included prospectively. Histological examination of the gallbladder specimens was done for preneoplastic lesions. LOH at 8 loci, that is 3p12, 3p14.2, 5q21, 9p21, 9q, 13q, 17p13, and 18q for tumor suppressor genes (DUTT1, FHIT, APC, p16, FCMD, RB1, p53, and DCC genes) that are associated with GBC was tested from microdissected preneoplastic lesions using microsatellite markers. These LOH were also tested in 30 GBC specimens.

RESULTS

Of the 350 gallbladder specimens from gallstone patients, hyperplasia was found in 32%, metaplasia in 47.8%, dysplasia in 15.7%, and carcinoma in situ in 0.6%. Hyperplasia, metaplasia, and dysplasia alone were found in 11.7%, 24.6%, and 1.4% of patients, respectively. A combination of hyperplasia and dysplasia, metaplasia and dysplasia, and hyperplasia, metaplasia, and dysplasia was found in 3.4%, 6.3%, and 4.3% of patients, respectively. LOH was present in 2.1% to 47.8% of all the preneoplastic lesions at different loci. Fractional allelic loss was significantly higher in those with dysplasia compared with other preneoplastic lesions (0.31 vs 0.22; P = 0.042). No preneoplastic lesion or LOH was found in normal gallbladders.

CONCLUSIONS

Patients with gallstones had a high frequency of preneoplastic lesions and accumulation of LOH at various tumor suppressor genes, suggesting a possible causal association of gallstones with GBC.

Forkhead box L1 is frequently downregulated in gallbladder cancer and inhibits cell growth through apoptosis induction by mitochondrial dysfunction

Background

Forkhead box L1 (FOXL1), considered as a novel candidate tumor suppressor, suppresses proliferation and invasion in certain cancers. However, the regulation and function of FOXL1 in gallbladder cancer (GBC) remains unclear.

Methods

FOXL1 expression at mRNA and protein levels in GBC tissues and cell lines were examined by RT-PCR, immunohistochemistry and western blot assay. FOXL1 expression in GBC cell lines was up-regulated by transfection with pcDNA-FOXL1. The effects of FOXL1 overexpression on cell proliferation, apoptosis, migration and invasion were evaluated in vitro or in vivo. In addition, the status of mediators involved in migration, invasion and apoptosis was examined using western blot after transfection with pcDNA-FOXL1.

Results

FOXL1 was frequently downregulated in GBC tissues and cell lines. Its higher expression is associated with better prognosis, while its lower expression is correlated with advanced TNM stage and poor differentiation. FOXL1 overexpression in NOZ cells significantly suppresses cell proliferation, migration and invasion in vitro and tumorigenicity in nude mice. FOXL1 overexpression disrupted mitochondrial transmembrane potential and triggered mitochondria-mediated apoptosis in NOZ cells. In addition, FOXL1 overexpression suppressed ZEB1 expression and induced E-cadherin expression in NOZ cells.

Conclusion

Our findings suggested that dysregulated FOXL1 is involved in tumorigenesis and progression of GBC and may serve as a predictor of clinical outcome or even a therapeutic target for patients with GBC.

Xanthogranulomatous cholecystitis: a clinicopathological study of its association with gallbladder carcinoma

OBJECTIVES

To determine the distribution of macrophages (MΦ) in both xanthogranulomatous cholecystitis (XGC) and gallbladder carcinoma (GBC) and to analyze the association between XGC and GBC.

METHODS

From January 2009 to June 2011, 110 patients with gallbladder diseases, including 35 with GBC, 45 with XGC and 30 with chronic cholecystitis (CC), were enrolled. Immunohistochemistry stain and real-time polymerase chain reaction using oncogenes (BCL-2, c-Myc) and anti-oncogene genes (p53, p21) were performed, serum expressions of tumor marker (CA19-9, CA724 and CA242) were also conducted. MΦ were used to determine their potential role in the carcinogenesis of GBC.

RESULTS

BCL-2 and c-Myc expressions gradually increased among CC, XGC and GBC (P = 0.032 and P = 0.020, respectively); while p53 and p21 were similar in the three groups (P = 0.167 and P = 0.122, respectively). Serum BCL-2 and c-Myc were significantly correlated with their tissue levels; in terms of serum tumor markers, which gradually increased among CC, XGC and GBC, however, CA242 and CA724 were both negative in XGC but positive in GBC. Furthermore, gradually increasing MΦ counts were observed among CC, XGC and GBC groups; c-Myc and CA724 were independent predictors for the differentiation of XGC and GBC.

CONCLUSIONS

XGC is an uncommon inflammatory condition distinct from CC and may be associated with the precancerous nature of GBC for its upregulated oncogenes and MΦ biology. c-Myc and CA724 were independent predictors for the differentiation of XGC and 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.