Identification of liver-intestine cadherin in hepatocellular carcinoma--a potential disease marker

Cadherin-17 (CDH17) expression in human cancer: A tissue microarray study on 18,131 tumors

Cadherin-17 (CDH17) is a membranous cell adhesion protein predominantly expressed in intestinal epithelial cells. CDH17 is therefore considered a possible diagnostic and therapeutic target. This study was to comprehensively determine the expression of CDH17 in cancer and to further assess the diagnostic utility of CDH17 immunohistochemistry (IHC). A tissue microarray containing 14,948 interpretable samples from 150 different tumor types and subtypes as well as 76 different normal tissue types was analyzed by IHC. In normal tissues, a membranous CDH17 staining was predominantly seen in the epithelium of the intestine and pancreatic excretory ducts. In tumors, 53 of 150 analyzed categories showed CDH17 positivity including 26 categories with at least one strongly positive case. CDH17 positivity was most common in epithelial and neuroendocrine colorectal neoplasms (50.0%-100%), other gastrointestinal adenocarcinomas (42.7%-61.6%), mucinous ovarian cancer (61.1%), pancreatic acinar cell carcinoma (28.6%), cervical adenocarcinoma (52.6%), bilio-pancreatic adenocarcinomas (40.5-69.8%), and other neuroendocrine neoplasms (5.6%-100%). OnIy 9.9% of 182 pulmonary adenocarcinomas were CDH17 positive. In colorectal adenocarcinomas, reduced CDH17 staining was linked to high pT (p = 0.0147), nodal metastasis (p = 0.0041), V1 (p = 0.0025), L1 (p = 0.0054), location in the right colon (p = 0.0033), and microsatellite instability (p < 0.0001). The CDH17 expression level was unrelated to tumor phenotype in gastric and pancreatic cancer. In summary, our comprehensive overview on CDH17 expression in human tumors identified various tumor entities that might often benefit from anti-CDH17 therapies and suggest utility of CDH17 IHC for the distinction of metastatic gastrointestinal or bilio-pancreatic adenocarcinomas (often positive) from primary pulmonary adenocarcinomas (mostly negative).

Aberrant expression of SATB2, CDX2, CDH17 and CK20 in hepatocellular carcinoma: a pathological, clinical and outcome study

AIMS

Data regarding expression of intestinal markers in hepatocellular carcinoma (HCC) are limited. We determined the clinicopathological associations of cytokeratin (CK)19, a progenitor liver epithelial cell marker as well as biliary epithelial marker, and intestinal immunohistochemical markers expression in HCC and assessed their prognostic value.

METHODS AND RESULTS

Tissue sections and/or tissue microarrays (TMAs) from 202 known HCCs were immunostained using CK19, CK20, CDH17, CDX2 and SATB2 antibodies. Haematoxylin and eosin (H&E)-stained slides were reviewed for tumour grading. Clinical and oncological outcomes were retrieved. Associations of staining with clinicopathological features and survival outcomes were evaluated. CK19, CK20, CDH17, CDX2 and SATB2 were positive in 12.8, 5.4, 10.3, 8.6 and 59.9%, respectively. All but SATB2 were strongly associated with higher tumour grade and AFP levels > 400 ng/ml (P < 0.05). CK19-positive HCC were more likely to express CDX2 (P = 0.001), CDH17 (P < 0.001) and/or CK20 (P = 0.012). CK20, CDX2 and CDH17 co-expression was seen in five cases (2.5%). CK19 and SATB2 positivity, tumour size ≥ 5 cm, background cirrhosis, AFP > 400 ng/ml and having no treatment were associated with decreased overall survival by log-rank test and univariable proportional hazards regression. However, in a multivariable model, CK19 and SATB2 positivity were not independent predictors of decreased survival while their association with known poor prognosticators in HCC was evident.

CONCLUSIONS

HCC can express markers of intestinal differentiation. This phenotypical aberrancy correlates with variable clinicopathological parameters, some of which are independent predictors of poor survival.

Crystal structure of the nonclassical cadherin-17 N-terminus and implications for its adhesive binding mechanism

The cadherin superfamily of calcium-dependent cell-adhesion proteins has over 100 members in the human genome. All members of the superfamily feature at least a pair of extracellular cadherin (EC) repeats with calcium-binding sites in the EC linker region. The EC repeats across family members form distinct complexes that mediate cellular adhesion. For instance, classical cadherins (five EC repeats) strand-swap their N-termini and exchange tryptophan residues in EC1, while the clustered protocadherins (six EC repeats) use an extended antiparallel `forearm handshake' involving repeats EC1-EC4. The 7D-cadherins, cadherin-16 (CDH16) and cadherin-17 (CDH17), are the most similar to classical cadherins and have seven EC repeats, two of which are likely to have arisen from gene duplication of EC1-2 from a classical ancestor. However, CDH16 and CDH17 lack the EC1 tryptophan residue used by classical cadherins to mediate adhesion. The structure of human CDH17 EC1-2 presented here reveals features that are not seen in classical cadherins and that are incompatible with the EC1 strand-swap mechanism for adhesion. Analyses of crystal contacts, predicted glycosylation and disease-related mutations are presented along with sequence alignments suggesting that the novel features in the CDH17 EC1-2 structure are well conserved. These results hint at distinct adhesive properties for 7D-cadherins.

Beyond N-Cadherin, Relevance of Cadherins 5, 6 and 17 in Cancer Progression and Metastasis

Cell-cell adhesion molecules (cadherins) and cell-extracellular matrix adhesion proteins (integrins) play a critical role in the regulation of cancer invasion and metastasis. Although significant progress has been made in the characterization of multiple members of the cadherin superfamily, most of the published work continues to focus in the switch E-/N-cadherin and its role in the epithelial-mesenchymal transition. Here, we will discuss the structural and functional properties of a subset of cadherins (cadherin 17, cadherin 5 and cadherin 6) that have an RGD motif in the extracellular domains. This RGD motif is critical for the interaction with α2β1 integrin and posterior integrin pathway activation in cancer metastatic cells. However, other signaling pathways seem to be affected by RGD cadherin interactions, as will be discussed. The range of solid tumors with overexpression or "de novo" expression of one or more of these three cadherins is very wide (gastrointestinal, gynaecological and melanoma, among others), underscoring the relevance of these cadherins in cancer metastasis. Finally, we will discuss different evidences that support the therapeutic use of these cadherins by blocking their capacity to work as integrin ligands in order to develop new cures for metastatic patients.

Disruption of oncogenic liver-intestine cadherin (CDH17) drives apoptotic pancreatic cancer death

Liver-intestine cadherin (CDH17) has been known to function as a tumor stimulator and diagnostic marker for almost two decades. However, its function in highly malignant pancreatic cancer (PC) has yet to be elucidated. Using different strategies including siRNA, shRNA, and CRISPR technology, we successfully induced knockdown and knockout of CDH17 in Panc02-H7 cells and established the corresponding stable cell lines. With these cells, we demonstrated that loss of CDH17 function not only suppressed Panc02-H7 cell growth in vitro but also significantly slowed orthotopic tumor growth in vivo, resulting in the significant life extension. In vitro studies demonstrated that impairing CDH17 inhibited cell proliferation, colony formation, and motility by mechanistically modulating pro- and anti-apoptosis events in PC cells, as CDH17 suppression obviously increased expression of Bad, cytochrome C, cleaved caspase 3, and cleaved PARP, and reduced expression of Bcl-2, Survivin, and pAkt. In vivo studies showed CDH17 knockout resulted in apoptotic PC tumor death through activating caspase-3 activity. Taken together, CDH17 functions as an oncogenic molecule critical to PC growth by regulating tumor apoptosis signaling pathways and CDH17 could be targeted to develop an anti-PC therapeutic approach.

Generation of functional hepatocyte 3D discoids in an acoustofluidic bioreactor

Ultrasonic standing wave systems have previously been used for the generation of 3D constructs for a range of cell types. In the present study, we cultured cells from the human hepatoma Huh7 cell line in a Bulk Acoustic Wave field and studied their viability, their functions, and their response to the anti-cancer drug, 5 Fluorouracil (5FU). We found that cells grown in the acoustofluidic bioreactor (AFB) expressed no reduction in viability up to 6 h of exposure compared to those cultured in a conventional 2D system. In addition, constructs created in the AFB and subsequently cultured outside of it had improved functionality including higher albumin and urea production than 2D or pellet cultures. The viability of Huh7 cells grown in the ultrasound field to 5FU anti-cancer drug was comparable to that of cells cultured in the 2D system, showing rapid diffusion into the aggregate core. We have shown that AFB formed 3D cell constructs have improved functionality over the conventional 2D monolayer and could be a promising model for anti-cancer drug testing.

Silencing of cadherin-17 enhances apoptosis and inhibits autophagy in colorectal cancer cells

Cadherin-17 (CDH17), a structurally unique member of the non-classical cadherin family, is associated with poor survival, cell proliferation, and metastasis in colorectal cancer. However, the role of CDH17 in the apoptosis and autophagy of colorectal cancer cells remains unclear. Here, we aimed to investigate the effect of CDH17 knockdown on autophagy and apoptosis in colorectal cancer cells. We inhibited CDH17 expression in KM12SM and KM12C colorectal cancer cells by RNA interference and found that silencing of CDH17 significantly inhibited cell viability and increased apoptosis in KM12SM and KM12C cells. In addition, silencing of CDH17 significantly increased the expression of cleaved caspase-3 and Bax and decreased the expression of Bcl-2. Concurrently, silencing of CDH17 significantly inhibited the conversion of LC3-I to LC3-II and decreased the formation of LC3⁺ autophagic vacuoles and the accumulation of acidic vesicular organelles, indicating that autophagy was significantly inhibited in KM12SM and KM12C cells. Additionally, treatment with the autophagy-specific activator rapamycin attenuated apoptosis in CDH17-knockdown cells and as indicated by decreased caspase-3 activity, decreased expression of cleaved caspase-3 and Bax, and increased expression of Bcl-2. In conclusion, CDH17 silencing induced apoptosis and inhibited autophagy in KM12SM and KM12C cells, and this autophagy protected the cells from apoptotic cell death.

Determination of Cadherin-17 in Tumor Tissues of Different Metastatic Grade Using a Single Incubation-Step Amperometric Immunosensor

This paper reports the development of an amperometric immunosensing platform for the determination of cadherin-17 (CDH-17), an atypical adhesion protein involved in the progression, metastatic potential, and survival of high prevalence gastric, hepatocellular, and colorectal tumors. The methodology developed relies on the efficient capture and enzymatic labeling of the target protein on the magnetic microparticles (MBs) surface using commercial antibodies and amperometric transduction at screen-printed carbon electrodes (SCPEs) through the HRP/H₂O₂/HQ system. The developed immunosensing platform allows the selective determination of the target protein at low ng mL^-1 level (LOD of 1.43 ng mL^-1) in 45 min and using a single incubation step. The electrochemical immunosensor was successfully used for the accurate determination of the target protein in a small amount (0.5 μg) of raw lysates of colon cancer cells with different metastatic potential as well as in extracts from paraffin embedded cancer colon tissues of different metastatic grade.

RGD cadherins and α2β1 integrin in cancer metastasis: A dangerous liaison

We propose a new cadherin family classification comprising epithelial cadherins (cadherin 17 [CDH17], cadherin 16, VE-cadherin, cadherin 6 and cadherin 20) containing RGD motifs within their sequences. Expression of some RGD cadherins is associated with aggressive forms of cancer during the late stages of metastasis, and CDH17 and VE-cadherin have emerged as critical actors in cancer metastasis. After binding to α2β1 integrin, these cadherins promote integrin β1 activation, and thereby cell adhesion, invasion and proliferation, in liver and lung metastasis. Activation of α2β1 integrin provokes an affinity increase for type IV collagen, a major component of the basement membrane and a critical partner for cell anchoring in liver and other metastatic organs. Activation of α2β1 integrin by RGD motifs breaks an old paradigm of integrin classification and supports an important role of this integrin in cancer metastasis. Recently, synthetic peptides containing the RGD motif of CDH17 elicited highly specific and selective antibodies that block the ability of CDH17 RGD to activate α2β1 integrin. These monoclonal antibodies inhibit metastatic colonization in orthotopic mouse models of liver and lung metastasis for colorectal cancer and melanoma, respectively. Hopefully, blocking the cadherin RGD ligand capacity will give us control over the integrin activity in solid tumors metastasis, paving the way for development of new agents of cancer treatment.

Coupling CDH17 and CLDN18 markers for comprehensive membrane-targeted detection of human gastric cancer

Patients with gastric cancer typically face gastrectomies even when few or no nodal metastases are reported. Current procedures poorly predict lymphatic metastases; thus, evaluation of target molecules expressed on cancer cell membranes is necessary for in vivo detection. However, marker development is limited by the intratumoral heterogeneity of gastric cancer cells. In this study, multiple gene expression arrays of 42 systemic normal tissue samples and 56 gastric cancer samples were used to investigate two adhesion molecules, cadherin 17 (CDH17) and claudin 18 (CLDN18), which are intestinal and gastric markers, respectively. Expression of CDH17 and CLDN18 was partially redundant, but overlapped in 50 of 56 cases (89.3%). Tissue microarrays constructed using primary lesions and nodal metastases of 106 advanced gastric cancers revealed CDH17 and CLDN18 expression in 98 positive cases of 106 (92%). Hierarchical clustering classified gastric cancers into three subgroups, CDH17(++)/CLDN18(+/-), CDH17(++)/CLDN18(++) or CDH17(+)/CLDN18(+), and CDH17(-)/CLDN18(++/+/-). Whole tissue sections displayed strong, homogeneous staining for CDH17 and CLDN18. Together, these results indicate that CDH17 and CLDN18 are useful target molecules; moreover, their coupling can aid in the comprehensive detection and localization of gastric cancer metastases in vivo to overcome challenges associated with intratumoral heterogeneity.

Serine peptidase inhibitor Kazal type 1 (SPINK1) as novel downstream effector of the cadherin-17/β-catenin axis in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common type of liver cancer worldwide. Previously, we reported that cadherin-17 (CDH17) and its related CDH17/β-catenin axis may be responsible for inducing HCC in a subset of patients exhibiting CDH17 over-expression. Here we aimed at obtaining a better understanding of the CDH17-related HCC biology and to obtain further indications for the design of targeted therapies in CDH17 over-expressing HCC patients.

RESULTS

We found that SPINK1 acts as a downstream effector of the CDH17/β-catenin axis in HCC. In addition, we found that SPINK1 expression exhibited a positive correlation with CDH17 expression in human HCCs and was over-expressed in up to 70% of the tumors. We identified SPINK1 as a downstream effector of the CDH17/β-catenin axis using a spectrum of in vitro assays, including gene expression modulation and inhibitor assays, bioinformatics analyses and luciferase reporter assays. These in vitro results were validated in primary human HCCs, including the observation that alteration in β-catenin expression (a core component of the CDH17/β-catenin axis) in tumors affects SPINK1 serum levels in HCC patients. Similar to CDH17, SPINK1 expression in HCC cells was found to be associated with specific tumor-related properties via activating the c-Raf/MEK/ERK pathway.

CONCLUSIONS

Our current data substantiate our knowledge on the role of CDH17 in the biology of HCC and suggest that components of the CDH17/β-catenin axis may serve as therapeutic targets in CDH17 over-expressing HCC patients.

Knockdown of LI-cadherin alters expression of matrix metalloproteinase-2 and -9 and galectin-3

Liver-intestine cadherin (LI-cadherin), a novel member of the cadherin family, has been associated with the ability of a tumor to acquire an aggressive phenotype in several types of cancer. However, the exact function of LI-cadherin in the process of tumor invasion and metastasis remains predominantly unknown. To explore the effect of LI-cadherin on the regulation of matrix metalloproteinase-2 (MMP-2), MMP-9 and galectin-3 in LoVo human colorectal cancer cells, a RNA interference technique was applied to suppress the expression of LI‑cadherin. Subsequently, the mRNA levels and activities of MMP-2 and -9 were analyzed by semi-quantitative reverse transcription-polymerase chain reaction and gelatin zymography, respectively. Additionally, the protein expression level of galectin-3 was determined by western blot analysis. The results of the present study demonstrated that short hairpin RNA (shRNA)-silencing of LI-cadherin significantly increased the mRNA levels and activities of MMP‑2 and ‑9, and significantly reduced the protein levels of galectin‑3 in LoVo cells compared with control shRNA (P<0.05). These data indicate that knockdown of LI‑cadherin facilitates the invasion of cancer cells by degrading extracellular matrix components via activation of MMP‑2 and ‑9, and increases cancer cell adhesion and migration via altered expression of galectin‑3. This suggests that LI‑cadherin serves an important role in the invasion and metastasis of colorectal cancer, and may be used as a potential therapeutic target.

Proteogenomic Study beyond Chromosome 9: New Insight into Expressed Variant Proteome and Transcriptome in Human Lung Adenocarcinoma Tissues

This is a report of a human proteome project (HPP) related to chromosome 9 (Chr 9). To reveal missing proteins and undiscovered features in proteogenomes, both LC-MS/MS analysis and next-generation RNA sequencing (RNA-seq)-based identification and characterization were conducted on five pairs of lung adenocarcinoma tumors and adjacent nontumor tissues. Before our previous Chromosome-Centric Human Proteome Project (C-HPP) special issue, there were 170 remaining missing proteins on Chr 9 (neXtProt 2013.09.26 rel.); 133 remain at present (neXtProt 2015.04.28 rel.). In the proteomics study, we found two missing protein candidates that require follow-up work and one unrevealed protein across all chromosomes. RNA-seq analysis detected RNA expression for four nonsynonymous (NS) single nucleotide polymorphisms (SNPs) (in CDH17, HIST1H1T, SAPCD2, and ZNF695) and three synonymous SNPs (in CDH17, CST1, and HNF1A) in all five tumor tissues but not in any of the adjacent normal tissues. By constructing a cancer patient sample-specific protein database based on individual RNA-seq data and by searching the proteomics data from the same sample, we identified four missense mutations in four genes (LTF, HDLBP, TF, and HBD). Two of these mutations were found in tumor samples but not in paired normal tissues. In summary, our proteogenomic study of human primary lung tumor tissues detected additional and revealed novel missense mutations and synonymous SNP signatures, some of which are specific to lung cancers. Data from mass spectrometry have been deposited in the ProteomeXchange with the identifier PXD002523.

Cadherin 17 is a sensitive and specific marker for metanephric adenoma

Metanephric adenoma (MA) is a rare benign renal neoplasm that shares morphologic and immunophenotypic overlap with epithelial-predominant Wilms tumor (e-WT) and with the solid variant of papillary renal cell carcinoma (s-PRCC). Cadherin 17 (CDH17) is expressed primarily in the normal intestine and digestive tract tumors and has not been detected in tumors from other sites including the kidney. We investigated the diagnostic utility of CDH17 in differentiating between MA, e-WT, and s-PRCC. Immunohistochemical analysis for CDH17, CD57, AMACR, WT-1, and CDX2 was performed on 17 e-WTs, 15 s-PRCCs, and 21 MAs and assessed on the basis of a combined score of extent and intensity. Normal adult kidney parenchyma was negative for CDH17 staining. CDH17 was expressed in the late stages of fetal kidney development at the junction of the glomerular space and proximal nephron. The majority of MAs (81%) demonstrated membranous CDH17 immunoreactivity in all components (acinar, tubular, and papillary), whereas all cases of e-WTs and s-PRCCs were negative (P<0.0001). WT-1 was negative in s-PRCC and was positive in all cases of e-WT and MA. All MAs were strongly positive for CD57; however, this marker was also moderate to strongly positive in 6 (35%) e-WTs and 2 (13%) s-PRCCs. AMACR was strongly positive in all s-PRCCs, but moderate reactivity was seen in 3 (17%) e-WTs and 2 MAs (10%). CDH17 is a sensitive (81%) and highly specific (100%) marker for MA and should be considered in the immunohistochemistry panel for distinguishing MA from its mimics.

Cadherin-17 interacts with α2β1 integrin to regulate cell proliferation and adhesion in colorectal cancer cells causing liver metastasis

Liver metastasis is the major cause of death associated to colorectal cancer. Cadherin-17 (CDH17) is a non-classical, seven domain, cadherin lacking the conserved cytoplasmic domain of classical cadherins. CDH17 was overexpressed in highly metastatic human KM12SM and present in many other colorectal cancer cells. Using tissue microarrays, we observed a significant association between high expression of CDH17 with liver metastasis and poor survival of the patients. On the basis of these findings, we decided to study cellular functions and signaling mechanisms mediated by CDH17 in cancer cells. In this report, loss-of-function experiments demonstrated that CDH17 caused a significant increase in KM12SM cell adhesion and proliferation. Coimmunoprecipitation experiments demonstrated an interaction between CDH17 and α2β1 integrin with a direct effect on β1 integrin activation and talin recruitment. The formation of this complex, together with other proteins, was confirmed by mass spectrometry analysis. CDH17 modulated integrin activation and signaling to induce specific focal adhesion kinase and Ras activation, which led to the activation of extracellular signal-regulated kinase and Jun N-terminal kinase and the increase in cyclin D1 and proliferation. In vivo experiments showed that CDH17 silencing in KM12 cells suppressed tumor growth and liver metastasis after subcutaneous or intrasplenic inoculation in nude mice. Collectively, our data reveal a new function for CDH17, which is to regulate α2β1 integrin signaling in cell adhesion and proliferation in colon cancer cells for liver metastasis.

Targeting cadherin-17 inactivates Ras/Raf/MEK/ERK signaling and inhibits cell proliferation in gastric cancer

Cadherin-17 (CDH17), one member of 7D-cadherin superfamily, was overexpressed in gastric cancer (GC) and was associated with poor survival, tumor recurrence, metastasis, and advanced tumor stage. So far the cellular function and signaling mechanism of CDH17 in GC remains unclear. In this study, we showed that over 66% of GC cell lines (20/30) were CDH17 positive. Tissue microarray (TMA) assay showed that 73.6% Chinese GC tissues (159/216) were CDH17 positive, while 37% respective adjacent normal tissues were CDH17 positive. Knockdown of CDH17 inhibited cell proliferation, migration, adhesion and colony formation, and also induced a cell cycle arrest and apoptosis in AGS human GC cells. On the other side, overexpression of CDH17 facilitated MGC-803 GC tumor growth in nude mice. Antibody array and Western blotting assay demonstrated that knockdown of CDH17 in AGS cells down-regulated integrin β series proteins, further inactivated the Ras/Raf/MEK/ERK pathway and led to p53 and p21 accumulation, which resulted in proliferation inhibition, cell-cycle arrest and apoptosis induction. Collectively, our data firstly demonstrate the capacity of CDH17 to regulate the activity of Ras/Raf/MEK/ERK pathway for cell proliferation in GC, and suggest that CDH17 can serve as an attractive therapeutic target for future research.

Anti-cadherin-17 antibody modulates beta-catenin signaling and tumorigenicity of hepatocellular carcinoma

Cadherin-17 (CDH17) is an oncofetal molecule associated with poor prognostic outcomes of hepatocellular carcinoma (HCC), for which the treatment options are very limited. The present study investigates the therapeutic potential of a monoclonal antibody (Lic5) that targets the CDH17 antigen in HCC. In vitro experiments showed Lic5 could markedly reduce CDH17 expression in a dose-dependent manner, suppress β-catenin signaling, and induce cleavages of apoptotic enzymes caspase-8 and -9 in HCC cells. Treatment of animals in subcutaneous HCC xenograft model similarly demonstrated significant tumor growth inhibition (TGI) using Lic5 antibody alone (5 mg/kg, i.p., t.i.w.; ca.60–65% TGI vs. vehicle at day 28), or in combination with conventional chemotherapy regimen (cisplatin 1 mg/kg; ca. 85–90% TGI). Strikingly, lung metastasis was markedly suppressed by Lic5 treatments. Immunohistochemical and western blot analyses of xenograft explants revealed inactivation of the Wnt pathway and suppression of Wnt signaling components in HCC tissues. Collectively, anti-CDH17 antibody promises as an effective biologic agent for treating malignant HCC.

Liver-intestine-cadherin is a sensitive marker of intestinal differentiation during Barrett's carcinogenesis

BACKGROUND

Histopathologic differentiation between the stages of Barrett's carcinogenesis is often challenging. Liver-intestine (LI)-cadherin, an intestine-specific marker, is involved in intestinal metaplasia development in gastric and colon cancers and could be of value in diagnosis and differentiation.

AIMS

To examine the expression of LI-cadherin in the sequence of Barrett's carcinogenesis and to evaluate its association with clinicopathological data.

METHODS

LI-cadherin expression was immunohistologically investigated, by use of anti-CDH17 antibody, in gastric mucosa (GM) biopsies taken from the cardia (n = 9), in Barrett's esophagus (BE) without intraepithelial neoplasia (without IEN) (n = 9) and BE with low-grade IEN (n = 11), and in esophageal adenocarcinoma (ADC) (n = 13).

RESULTS

The immunoreactivity score was highest in adenocarcinoma (mean IRS = 4.0), and dropped gradually from BE with IEN and BE without IEN (mean IRS = 2.0) to cardia mucosa (IRS = 0). Similarly, the intensity of staining and the percentage of positive cells increased during the sequential stages of BE carcinogenesis. Comparative analysis showed that LI-cadherin expression was significantly different between cardiac epithelium and ADC. Also, percentage of positive cells in GM was significantly different from that in BE with IEN. LI-cadherin IRS was lower for tumors with poor differentiation than for moderately differentiated tumors, but the difference was not statistically significant.

CONCLUSIONS

LI-cadherin is a sensitive marker of intestinal metaplasia and can be helpful for early histologic diagnosis of Barrett's esophagus; it is, however, not significantly different between BE with and without IEN, and cannot be used to distinguish between these.

Tissue-specific cadherin CDH17 is a useful marker of gastrointestinal adenocarcinomas with higher sensitivity than CDX2

Cadherin 17 (CDH17) is a cell adhesion molecule expressed in intestinal epithelium and transcriptionally regulated by CDX2. We compared the usefulness of CDH17 as an immunohistochemical intestinal marker to that of CDX2 in gastrointestinal and extragastrointestinal carcinomas and nonneoplastic tissues. Nonneoplastic intestinal and pancreatic duct epithelia were CDH17-positive. Most esophageal (79%), gastric (86%), and colonic (99%) adenocarcinomas were CDH17-positive/CDX2-positive, whereas 1% of colonic, 18% of esophageal, and 10% of gastric adenocarcinomas were CDH17-negative/CDX2-negative. Rare colonic, esophageal, and gastric adenocarcinomas were CDH17-positive/CDX2-negative (1%, 3%, and 4%, respectively), and none were CDH17-negative/CDX2-positive. Diffuse CDH17 was also observed in all metastatic colon carcinomas, 20% of which were only focally CDX2-positive. Of intestinal low-grade neuroendocrine tumors, 74% coexpressed CDX2 and CDH17. CDH17 was also positive in 12% of pancreatic and 24% of bronchial neuroendocrine tumors, all of which were CDX2-negative. Pancreatic adenocarcinomas and cholangiocarcinomas were more frequently CDH17-positive than CDX2-positive (50% vs 27%, 53% vs 27%). One (2%) hepatocellular carcinoma was CDH17-positive/CDX2-negative. Nine percent of non-small cell lung cancers and 7% of endometrial carcinomas were CDH17-positive, whereas 3% of lung, 5% of endometrial, 3% of ovarian, and 2% of breast carcinomas were CDX2-positive. Thus, CDH17 is slightly more sensitive than CDX2 when detecting gastrointestinal adenocarcinomas.

Blockade of proliferation and migration of gastric cancer via targeting CDH17 with an artificial microRNA

Liver-intestine cadherin (CDH17) is a novel member of the cadherin superfamily implicated in gastric cancer progression. To determine the role of CDH17 in the process of gastric cancer invasive growth, in the present study, RNA interference mediated by recombinant lentivirus vectors expressing artificial CDH17 miRNA was applied to induce a long-lasting down-regulation of CDH17 gene expression in BGC823 cells. The expression levels of CDH17, tumor cell motility, migration potential, and pro-liferation were measured by flow cytometry, real-time RT-PCR, Western blot analysis, immunofluorescence staining, wound healing assay, and MTT assay, respectively. Results show that four recombinant plasmid expression vectors encoding pre-miRNA against CDH17, pcDNA-CDH17-miR-SR1, -SR2, -SR3, and -SR4 were constructed correctly and down-regulated the CDH17 mRNA levels by 5.5, 57, 91, and 98%, respectively, in BGC823 cells which had an overexpression of CDH17. We packaged the recombinant lentiviral vector for CDH17 RNA interference with pcDNA-CDH17-miR-SR4 which had the highest interfering efficiency and succeeded in construction of the stable transfectants. Of note, more than 90% knockdown of CDH17 expression in BGC823 cells was obtained by miRNA technique. The CDH17-miRNA-transfected cells showed significant decrease in cell proliferation, cell motility, and migration in comparison with the control cells. Thus, we proposed that CDH17 may be an oncogene up-regulating invasive features of gastric cancer cells and could be a hopeful target for the control of gastric cancer progression.

Dickkopfs and Wnt/β-catenin signalling in liver cancer

Liver cancer is the fifth and seventh most common cause of cancer in men and women, respectively. Wnt/β-catenin signalling has emerged as a critical player in both the development of normal liver as well as an oncogenic driver in hepatocellular carcinoma (HCC). Based on the current understanding, this article summarizes the possible mechanisms for the aberrant activation of this pathway with specific focus on HCC. Furthermore, we will discuss the role of dickkopfs (DKKs) in regulating Wnt/β-catenin signalling, which is poorly understood and understudied. DKKs are a family of secreted proteins that comprise at least four members, namely DKK1-DKK4, which act as inhibitors of Wnt/β-catenin signalling. Nevertheless, not all members antagonize Wnt/β-catenin signalling. Their functional significance in hepatocarcinogenesis remains to be further characterized for which these studies should provide new insights into the regulatory role of DKKs in Wnt/β-catenin signalling in hepatic carcinogenesis. Because of the important oncogenic roles, there are an increasing number of therapeutic molecules targeting β-catenin and the Wnt/β-catenin pathway for potential therapy of HCC.

HNF1α and CDX2 transcriptional factors bind to cadherin-17 (CDH17) gene promoter and modulate its expression in hepatocellular carcinoma

Cadherin-17 (CDH17) belongs to the cell adhesion cadherin family with a prominent role in tumorigenesis. It is highly expressed in human hepatocellular carcinoma (HCC) and is proposed to be a biomarker and therapeutic molecule for liver malignancy. The present study aims to identify the transcription factors which interact and regulate CDH17 promoter activity that might contribute to the up-regulation of CDH17 gene in human HCC. A 1-kb upstream sequence of CDH17 gene was cloned and the promoter activity was studied by luciferase reporter assay. By bioinformatics analysis, deletion and mutation assays, and chromatin immunoprecipitation studies, we identified hepatic nuclear factor 1α (HNF1α) and caudal-related homeobox 2 (CDX2) binding sites at the proximal promoter region which modulate the CDH17 promoter activities in two HCC cell lines (Hep3B and MHCC97L). A consistent down-regulation of CDH17 and the two transcriptional activators (HNF1α and CDX2) expression was found in the liver of mouse during development, as well as in human liver cancer cells with less metastatic potential. Suppression of HNF1α and CDX2 expression by small interfering RNA (siRNA) significantly down-regulated expressions of CDH17 and its downstream target cyclin D1 and the viability of HCC cells in vitro. In summary, we identified the minimal promoter region of CDH17 that is regulated by HNF1α and CDX2 transcriptional factors. The present findings enhance our understanding on the regulatory mechanisms of CDH17 oncogene in HCC, and may shed new insights into targeting CDH17 expression as potential therapeutic intervention for cancer treatment.

AXL receptor kinase is a mediator of YAP-dependent oncogenic functions in hepatocellular carcinoma

Yes-associated protein (YAP) is a downstream effector of the Hippo signaling pathway, which controls organ expansion and tissue development. We have recently defined the tumorigenic potential and clinical significance of the YAP1 oncogene in human hepatocellular carcinoma (HCC). The present study aims to define the tumorigenic properties of YAP in HCC and elucidate the related downstream signaling mechanism. In a gain-of-function study, we demonstrated that ectopic increased expression of YAP in the immortalized non-tumorigenic hepatocyte cell line MIHA confers tumorigenic and metastatic potentials, as evidenced by (1) enhanced aptitudes in cell viability, anchorage-independent growth, migration and invasion; (2) tumor formation in a xenograft mouse model; and (3) induction of HCC biomarker α-fetoprotein and activation of mitogen-activated protein kinase. Furthermore, we have identified AXL, a receptor tyrosine kinase, as a key downstream target that drives YAP-dependent oncogenic functions. RNAi-mediated knockdown of AXL expression decreased the ability of YAP-expressing MIHA cells and of the primary HCC cell line to proliferate and invade. These results indicate that AXL is a mediator of YAP-dependent oncogenic activities and implicates it as a potential therapeutic target for HCC.

Comparison of six immunohistochemical markers for the histologic diagnosis of neoplasia in Barrett's esophagus

In esophageal neoplasms, the histopathologic differentiation between Barrett's esophagus with or without intraepithelial neoplasia and adenocarcinoma is often challenging. Immunohistochemistry might help to differentiate between these lesions. The expression of CDX2, LI-cadherin, mucin 2 (MUC2), blood group 8 (BG8, Lewis(y)), claudin-2, and villin was investigated in normal gastroesophageal (n = 23) and in Barrett's (n = 17) mucosa, in low-grade (n = 12) and high-grade (n = 9) intraepithelial neoplasia (IEN) as well as in esophageal adenocarcinoma (n = 16), using immunohistochemistry. For CDX2 and LI-cadherin, the immunoreactivity score was highest in IEN while for MUC2, BG8, and villin, it dropped gradually from Barrett's via IEN to adenocarcinoma, and expression of Claudin-2 was only weak and focal in all lesions. The expression of MUC2 and LI-cadherin differed significantly between all examined lesions except between low-grade and high-grade IEN. MUC2 and LI-cadherin are useful immunohistochemical markers for the differentiation between normal glandular mucosa, Barrett's mucosa, IEN, and invasive carcinoma of the esophagus; however, none of the examined markers was helpful for the differentiation between low-grade and high-grade IEN.

Lentiviral-mediated miRNA against liver-intestine cadherin suppresses tumor growth and invasiveness of human gastric cancer

Liver-intestine cadherin (CDH17) represents a novel type of cadherin within the cadherin superfamily, and is distinguished from other cadherins by its distinct structural and functional features. Our previous studies had identified that increased CDH17 was significantly associated with tumor differentiation and lymph node metastasis in gastric cancer. In this study, we tested the hypothesis that CDH17 was associated with proliferation and invasiveness in gastric cancer using recombinant lentivirus-mediated miRNA targeting to CDH17 both in vitro and in vivo. We also detected the activity of matrix metalloproteinase (MMP)-2 and MMP-9 with gelatin zymography to explore the mechanisms underlying the inhibition of the CDH17 gene. Our results showed that a well-differentiated gastric cancer cell line had higher CDH17 expression. Down-regulation of CDH17 inhibited proliferation, adherence, and invasion of the poorly differentiated BGC823 gastric cancer cells in vitro, and induced cell cycle arrest. The activities of MMP-2 and MMP-9 were lower in the CDH17-miRNA-transfected cells compared to the control cells. Using an in vivo tumor growth assay, we confirmed that CDH17 silencing could obviously slow the growth of gastric cancer derived from BGC823 cells. Taken together, we have demonstrated that CDH17 maybe a positive regulator for proliferative, adhesive, and invasive behaviors of gastric cancer.

Impairment of pre-mRNA splicing in liver disease: Mechanisms and consequences

Pre-mRNA splicing is an essential step in the process of gene expression in eukaryotes and consists of the removal of introns and the linking of exons to generate mature mRNAs. This is a highly regulated mechanism that allows the alternative usage of exons, the retention of intronic sequences and the generation of exonic sequences of variable length. Most human genes undergo splicing events, and disruptions of this process have been associated with a variety of diseases, including cancer. Hepatocellular carcinoma (HCC) is a molecularly heterogeneous type of tumor that usually develops in a cirrhotic liver. Alterations in pre-mRNA splicing of some genes have been observed in liver cancer, and although still scarce, the available data suggest that splicing defects may have a role in hepatocarcinogenesis. Here we briefly review the general mechanisms that regulate pre-mRNA splicing, and discuss some examples that illustrate how this process is impaired in liver tumorigenesis, and may contribute to HCC development. We believe that a more thorough examination of pre-mRNA splicing is still needed to accurately draw the molecular portrait of liver cancer. This will surely contribute to a better understanding of the disease and to the development of new effective therapies.

Genomic and proteomic biomarkers for diagnosis and prognosis of hepatocellular carcinoma

Hepatocellular carcinoma is one of the most deadly liver malignancies found worldwide, with hepatitis virus infection being the prominent risk factor for this lesion. Patients with hepatocellular carcinoma are usually first diagnosed when in the advanced stage; thus, long-term clinical outcomes are poor and patients have limited treatment options. Currently, surveillance of hepatocellular carcinoma relies upon serological testing of alpha-fetoprotein levels and hepatic ultrasonography, which have low sensitivity and specificity, and are sometimes operator-dependent, respectively. Therefore, discovery of new biomarkers for early and accurate detection of hepatocellular carcinoma would be of great clinical value. Genomic and proteomic approaches are two major laboratory platforms for the identification of candidate hepatocellular carcinoma biomarkers based on profiling and validating with tumor and nontumor clinical samples. Frequently, these diagnostic markers have been found in association with genetic aberrations, protein-level alterations, post-translational modifications and immune functions. With the discovery of these biomarkers, earlier detection of hepatocellular carcinoma in high-risk subjects (e.g., cirrhosis and hepatitis carriers) becomes possible, which will enable clinicians to offer patients better clinical management and more effective treatment modalities.

Role of cadherin-17 in oncogenesis and potential therapeutic implications in hepatocellular carcinoma

Cadherin is an important cell adhesion molecule that plays paramount roles in organ development and the maintenance of tissue integrity. Dysregulation of cadherin expression is often associated with disease pathology including tissue dysplasia, tumor formation, and metastasis. Cadherin-17 (CDH17), belonging to a subclass of 7D-cadherin superfamily, is present in fetal liver and gastrointestinal tract during embryogenesis, but the gene becomes silenced in healthy adult liver and stomach tissues. It functions as a peptide transporter and a cell adhesion molecule to maintain tissue integrity in epithelia. However, recent findings from our group and others have reported aberrant expression of CDH17 in major gastrointestinal malignancies including hepatocellular carcinoma (HCC), stomach and colorectal cancers, and its clinical association with tumor metastasis and advanced tumor stages. Furthermore, alternative splice isoforms and genetic polymorphisms of CDH17 gene have been identified in HCC and linked to an increased risk of HCC. CDH17 is an attractive target for HCC therapy. Targeting CDH17 in HCC can inhibit tumor growth and inactivate Wnt signaling pathway in concomitance with activation of tumor suppressor genes. Further investigation on CDH17-mediated oncogenic signaling and cognate molecular mechanisms would shed light on new targeting therapy on HCC and potentially other gastrointestinal malignancies.

CDX2 and LI-cadherin expression in esophageal mucosa: use of both markers can facilitate the histologic diagnosis of Barrett's esophagus and carcinoma

BACKGROUND

Barrett's mucosa is a risk factor for esophageal adenocarcinoma and should be detected at an early stage. CDX2 and liver-intestine (LI)-cadherin are intestine-specific markers. Aberrant CDX2 expression has been demonstrated in Barrett's metaplasia, esophagitis, and intestinal metaplasia of the stomach.

METHODS

The relationship between CDX2 and LI-cadherin expression was investigated in normal gastroesophageal (n = 24) and in Barrett's (n = 20) mucosa, in low-grade (n = 15) and high-grade (n = 13) intraepithelial neoplasia (IEN) as well as in esophageal adenocarcinoma (n = 16), using immunohistochemistry.

RESULTS

Nuclear positivity for CDX2 coupled with membranous expression of LI-cadherin was observed in about 70% of the epithelial cells of Barrett's mucosa. The intensity of staining and the percentage of positive cells increased within the sequential steps of low-grade to high-grade IEN, whereas the normal cylindric epithelium lacked the expression of both. In adenocarcinoma, the expression of LI-cadherin and CDX2 was significantly weaker or absent.

CONCLUSIONS

CDX2 and LI-cadherin are sensitive markers of intestinal metaplasia with or without dysplasia in the upper gastrointestinal tract. Both can be helpful for the early histologic diagnosis of Barrett's esophagus and its subsequent lesions; however, they do not significantly discern between different grades of dysplasia.

Circulating Lamin B1 (LMNB1) biomarker detects early stages of liver cancer in patients

Hepatocellular carcinoma (HCC) is a major liver malignancy possessing a high mortality rate and is particularly prevalent in China and Asia. While surgery is the most effective treatment for liver tumor, about 80% of HCC patients are inoperable at presentation and die early due to late diagnosis. For early cancer detection, we employed a proteomic expression profiling approach to identify biomarkers for early stages of HCC and subsequently assessed the clinical feasibility of a novel marker in plasma. Frozen liver tissues from a retrospective cohort of 75 liver patients (39 HCCs, 20 cirrhosis, and 16 nondiseased subjects) were subjected to proteome-wide expression profiling by 2-DE. MALDI-TOF/TOF was used to identify differentially expressed proteins, which were further confirmed by immunoblotting, qPCR, and immunohistochemistry. Conventional RT-PCR was employed to further analyze the abundance of selected biomarker at mRNA level in a separate cohort of 63 plasma samples (35 HCCs, 16 liver cirrhosis, 12 healthy individuals). We successfully identified lamin B1 (LMNB1) that was significantly upregulated in HCC tumors and present in patients' plasma. LMNB1 functions in nuclear envelope lamina and possesses a transcriptional coregulatory activity having an important role in DNA replication, cellular aging, and stress responses. Clinically, the expression level of lamin B1 correlated positively with tumor stages, tumor sizes, and number of nodules. Our findings further showed elevation of circulating LMNB1 marker in plasma could detect early stages of HCC patients, with 76% sensitivity and 82% specificity. In conclusion, lamin B1 is a clinically useful biomarker for early stages of HCC in tumor tissues and plasma, and warrants further clinical investigation.

Yes-associated protein is an independent prognostic marker in hepatocellular carcinoma

BACKGROUND

Yes-associated protein (YAP), a downstream target of the Hippo signaling pathway, was recently linked to hepatocarcinogenesis in a mouse hepatocellular carcinoma (HCC) model. The objective of the current study was to investigate the clinical significance of YAP in HCC and its prognostic values in predicting survival and tumor recurrence.

METHODS

The authors collected 177 pairs of tumor and adjacent nontumor tissue from HCC patients with definitive clinicopathologic and follow-up data. YAP expression was determined by immunohistochemistry, Western blot analysis, and quantitative polymerase chain reaction. Association of YAP with each clinicopathologic feature was analyzed by Pearson chi-square test, and HCC-specific disease-free survival and overall survival by Kaplan-Meier curves and log-rank test. Multivariate Cox regression analyses of YAP in HCC were also performed.

RESULTS

YAP was expressed in the majority of HCC cases (approximately 62%) and mainly accumulated in the tumor nucleus. Overexpression of YAP in HCC was significantly associated with poorer tumor differentiation (Edmonson grade; P = .021) and high serum alpha-fetoprotein (AFP) level (P < .001). Kaplan-Meier and Cox regression data indicated that YAP was an independent predictor for HCC-specific disease-free survival (hazards ratio [HR], 1.653; 95% confidence interval [95% CI], 1.081-2.528 [P = .02]) and overall survival (HR, 2.148; 95% CI, 1.255-3.677 [P = .005]).

CONCLUSIONS

YAP is an independent prognostic marker for overall survival and disease-free survival times of HCC patients and clinicopathologically associated with tumor differentiation and serum AFP level. It is a potential therapeutic target for this aggressive malignancy.

Targeting cadherin-17 inactivates Wnt signaling and inhibits tumor growth in liver carcinoma

Hepatocellular carcinoma (HCC) is a lethal malignancy for which there are no effective therapies. To develop rational therapeutic approaches for treating this disease, we are performing proof-of-principle studies targeting molecules crucial for the development of HCC. Here, we show that cadherin-17 (CDH17) adhesion molecule is up-regulated in human liver cancers and can transform premalignant liver progenitor cells to produce liver carcinomas in mice. RNA interference-mediated knockdown of CDH17 inhibited proliferation of both primary and highly metastatic HCC cell lines in vitro and in vivo. The antitumor mechanisms underlying CDH17 inhibition involve inactivation of Wnt signaling, because growth inhibition and cell death were accompanied by relocalization of beta-catenin to the cytoplasm and a concomitant reduction in cyclin D1 and an increase in retinoblastoma.

CONCLUSION

Our results identify CDH17 as a novel oncogene in HCC and suggest that CDH17 is a biomarker and attractive therapeutic target for this aggressive malignancy.

Liver-intestine cadherin predicts microvascular invasion and poor prognosis of hepatitis B virus-positive hepatocellular carcinoma

BACKGROUND

Liver-intestine cadherin (LI-cadherin; CDH-17) is a new member of the cadherin superfamily with distinct structural and functional features. The study was designed to investigate the role of LI-cadherin in tumor invasion and prognosis of human hepatitis B virus (HBV)-positive hepatocellular carcinoma (HCC).

METHODS

LI-cadherin expression in HBV-positive hepatocellular carcinoma cell lines with low- and high-invasive potentials was evaluated by Western-blot, immunofluorescence, and real-time polymerase chain reaction (PCR) analyses. The role of LI-cadherin in tumor invasion was also evaluated in vitro by a small-interfering ribonucleic acid (siRNA)-mediated approach. The prognostic significance of LI-cadherin was validated in a cohort of HBV-positive HCC patients by immunohistochemistry and Western-blot.

RESULTS

Significant high levels of LI-cadherin mRNA and protein were found in the high-invasive HCCLM3 as compared with those in low-invasive PLC/PRF/5 and Hep3B cell line. Cell migration, adhesion to extracellular matrix, and matrigel invasion were significantly reduced after LI-cadherin knockdown in HCCLM3 cells. Immunohistochemical analysis of 255 HBV-positive HCC cases showed that overexpression of LI-cadherin was well correlated with microvascular invasion, which was confirmed by Western-blot in 32 tumor tissues, and its overexpression was strongly associated with shorter overall survival as well as higher incidence of tumor recurrence.

CONCLUSIONS

LI-cadherin is predictive of microvascular invasion and poor prognosis of HBV-positive HCC, and would be a potential useful intervention target for HCC.

Yes-associated protein is an independent prognostic marker in hepatocellular carcinoma

BACKGROUND

Yes-associated protein (YAP), a downstream target of the Hippo signaling pathway, was recently linked to hepatocarcinogenesis in a mouse hepatocellular carcinoma (HCC) model. The objective of the current study was to investigate the clinical significance of YAP in HCC and its prognostic values in predicting survival and tumor recurrence.

METHODS

The authors collected 177 pairs of tumor and adjacent nontumor tissue from HCC patients with definitive clinicopathologic and follow-up data. YAP expression was determined by immunohistochemistry, Western blot analysis, and quantitative polymerase chain reaction. Association of YAP with each clinicopathologic feature was analyzed by Pearson chi-square test, and HCC-specific disease-free survival and overall survival by Kaplan-Meier curves and log-rank test. Multivariate Cox regression analyses of YAP in HCC were also performed.

RESULTS

YAP was expressed in the majority of HCC cases (approximately 62%) and mainly accumulated in the tumor nucleus. Overexpression of YAP in HCC was significantly associated with poorer tumor differentiation (Edmonson grade; P = .021) and high serum alpha-fetoprotein (AFP) level (P < .001). Kaplan-Meier and Cox regression data indicated that YAP was an independent predictor for HCC-specific disease-free survival (hazards ratio [HR], 1.653; 95% confidence interval [95% CI], 1.081-2.528 [P = .02]) and overall survival (HR, 2.148; 95% CI, 1.255-3.677 [P = .005]).

CONCLUSIONS

YAP is an independent prognostic marker for overall survival and disease-free survival times of HCC patients and clinicopathologically associated with tumor differentiation and serum AFP level. It is a potential therapeutic target for this aggressive malignancy.

A protein-based set of reference markers for liver tissues and hepatocellular carcinoma

Background

During the last decade, investigations have focused on revealing genes or proteins that are involved in HCC carcinogenesis using either genetic or proteomic techniques. However, these studies are overshadowed by a lack of good internal reference standards. The need to identify "housekeeping" markers, whose expression is stable in various experimental and clinical conditions, is therefore of the utmost clinical relevance in quantitative studies. This is the first study employed 2-DE analysis to screen for potential reference markers and aims to correlate the abundance of these proteins with their level of transcript expression.

Methods

A Chinese cohort of 224 liver tissues samples (105 cancerous, 103 non-tumourous cirrhotic, and 16 normal) was profiled using 2-DE analysis. Expression of the potential reference markers was confirmed by western blot, immunohistochemistry and real-time quantitative PCR. geNorm algorithm was employed for gene stability measure of the identified reference markers.

Results

The expression levels of three protein markers beta-actin (ACTB), heat shock protein 60 (HSP60), and protein disulphide isomerase (PDI) were found to be stable using p-values (p > 0.99) as a ranking tool in all 224 human liver tissues examined by 2-DE analysis. Of high importance, ACTB and HSP 60 were successfully validated at both protein and mRNA levels in human hepatic tissues by western blot, immunohistochemistry and real-time quantitative PCR. In addition, no significant correlation of these markers with any clinicopathological features of HCC and cirrhosis was found. Gene stability measure of these two markers with other conventionally applied housekeeping genes was assessed by the geNorm algorithm, which ranked ACTB and HSP60 as the most stable genes among this cohort of clinical samples.

Conclusion

Our findings identified 2 reference markers that exhibited stable expression across human liver tissues with different conditions thus should be regarded as reliable reference moieties for normalisation of gene and protein expression in clinical research employing human hepatic tissues.

Cell Adhesion Dynamics and Actin Cytoskeleton Reorganization in HepG2 Cell Aggregates

The temporal dependence of cytoskeletal remodelling on cell-cell contact in HepG2 cells has been established here. Cell-cell contact occurred in an ultrasound standing wave trap designed to form and levitate a 2-D cell aggregate, allowing intercellular adhesive interactions to proceed, free from the influences of solid substrata. Membrane spreading at the point of contact and change in cell circularity reached 50% of their final values within 2.2 min of contact. Junctional F-actin increased at the interface but lagged behind membrane spreading, reaching 50% of its final value in 4.4 min. Aggregates had good mechanical stability after 15 min in the trap. The implication of this temporal dependence on the sequential progress of adhesion processes is discussed. These results provide insight into how biomimetic cell aggregates with some liver cell functions might be assembled in a systematic, controlled manner in a 3-D ultrasound trap.

Li-cadherin is inversely correlated with galectin-3 expression in gastric cancer

The aims of this study were to examine the expressions of Li-cadherin and Galectin-3 in gastric cancer, and the correlation between Li-cadherin and Galectin-3 in gastric cancer was also analyzed. The present study investigated the expression level of Li-cadherin and Galectin-3 by immunohistochemistry and semiquantitative polymerase chain reaction (PCR), and correlated this with clinicopathologic parameters in 91 cases of gastric cancer. The correlation between expression levels of Li-cadherin and Galectin-3 was analyzed by Spearman correlation analysis. The expression level of Li-cadherin mRNA was correlated to differentiation and lymph node metastasis, and the expression level of Galectin-3 was related to TNM staging, differentiation and lymph node metastasis. On Spearman correlation analysis, a definitive negative correlation was found between the expression levels of Li-cadherin and Galectin-3 in gastric cancerous tissues. We postulate that interaction between Li-cadherin and Galectin-3 may play an important role in the development of gastric cancer.

A clinicopathological study on the expression of cadherin-17 and caudal-related homeobox transcription factor (CDX2) in human gastric carcinoma

AIMS

To analyse the clinicopathological characteristics of the expression of cadherin-17 (CDH17) and caudal-related homeobox transcription factor (CDX2) in human gastric carcinoma, and to evaluate the clinical significance of these two markers in the histological classification and prognosis of gastric carcinoma.

MATERIALS AND METHODS

CDH17, CDX2 protein expression in paraffin-embedded specimens gathered from 166 patients with gastric carcinoma were detected by immunohistochemistry. The association of CDH17, CDX2 protein expression with the clinicopathological characteristics, and with the prognosis of gastric carcinoma were subsequently assessed.

RESULTS

CDH17, nucleus and cytoplasm CDX2 expression were positively expressed in 101/166 (60.8%), 59/166 (35.5%) and 57/166 (34.3%) gastric carcinoma patients, respectively. The expression of both CDH17 and CDX2 is associated with the intestinal-type gastric carcinoma (P<0.01). Positive expression of CDH17 was significantly associated with the depth of gastric wall invasion (P=0.04), lymph node metastasis (P<0.01) and stages of gastric carcinoma (P=0.01). Positive expression of CDX2 in the nucleus was mainly found in male patients (P=0.02), in early stage (P=0.01) and medullary-type gastric carcinoma (P=0.02). There was a negative association between nuclear CDX2 expression and lymph node metastasis of gastric carcinoma (P<0.01). The combined expression of CDH17 and CDX2 was significantly lower in diffuse-type carcinoma than intestinal- or mixed-type carcinoma (P<0.01 and P=0.01, respectively). The patients with CDH17 expression associated with poor prognosis of gastric carcinoma (P<0.01), as opposed to patients with CDX2 expression (P<0.01). The survival rate of patients with CDH17+/CDX2- expression was the lowest (P<0.01), and conjoined expressions of CDH17+/CDX2- and CDH17+/CDX2+ were independent prognostic indicators of gastric carcinoma (both P<0.01).

CONCLUSION

The results suggest that the expression of CDH17 or CDX2 may be an important feature of gastric carcinoma. A combined detection of CDH17/CDX2 co-expression may benefit us in predicting the prognosis of gastric carcinoma.

Liver intestine-cadherin (CDH17) haplotype is associated with increased risk of hepatocellular carcinoma

PURPOSE

Hepatocellular carcinoma (HCC), the most common form of liver cancer, is a leading cause of cancer death worldwide. We previously showed that aberrant mRNA splicing of the liver intestine-cadherin gene CDH17 in liver tissues was triggered by the specific constellation of two CDH17 single nucleotide polymorphisms (651T and IVS6+35G). CDH17 aberrant splicing was highly associated with tumor dissemination and shorter survival of HCC patients. Consequently, it is highly relevant to assess whether the presence of these single nucleotide polymorphisms in the general population represents a risk to the development of HCC.

EXPERIMENTAL DESIGN

We conducted a case-control study including 164 HCC and 99 cirrhosis patients and 293 healthy controls. Genotyping was done by PCR and direct sequencing. Odds ratio (OR) and chi2 analysis were used to analyze genotypes and haplotypes.

RESULTS

Genotypes 651TT [OR, 2.62; 95% confidence interval (95% CI), 1.34-5.03] and IVS6+35 GG (OR, 1.95; 95% CI, 1.04-3.62) were highly associated with HCC disease. The 651T (C>T) and IVS6+35G (A>G) alleles were also overrepresented in HCC patients and, in particular, the T-G haplotype was the most prevalent in HCC patients when compared with healthy controls (OR, 1.57; 95% CI, 1.167-2.109; P=0.004), which was in agreement with the aberrant splicing observed in tumor tissues. There was no significant difference in genotype and allele frequencies between cirrhosis patients and controls.

CONCLUSION

The functional T-G haplotype of CDH17 (651 C>T and IVS6+35A>G) is a genetic susceptibility factor for the development of HCC in a Chinese population.

The prognostic significance of E-cadherin and liver intestine-cadherin expression in colorectal cancer

PURPOSE

The significance of liver intestine-cadherin as a potential marker has been growing in the field of oncology, because of its unique features compared with classic cadherins. We investigated the coexpression patterns of E-cadherin and liver intestine-cadherin in colorectal cancer, and determined whether differences in expression patterns were associated with clinicopathologic parameters and also which relationship between these two adhesion molecules existed in colorectal cancer.

METHODS

Expression pattern of E-cadherin and liver intestine-cadherin was investigated immunohistochemically in 207 colorectal cancers along with clinicopathologic parameters.

RESULTS

Reduced expression of liver intestine-cadherin was detected in 51 percent (n = 105) of tumors. Such expression was found to be associated with tumoral dedifferentiation (P = 0.015) and in a multivariate analysis was associated with a significant worse overall survival after adjustment for tumor stage, differentiation, and E-cadherin status (hazard ratio, 1.951; 95 percent confidence interval, 1.06-3.592; P = 0.032). Fifteen percent (n = 32) of tumors showed reduced expression of E-cadherin and had relationship with tumoral dedifferentiation (P < 0.001), lymph node metastasis (P = 0.004), and advanced stage (P = 0.029). Reduced expression of E-cadherin was associated with short overall survival (P = 0.028); however, in a multivariate analysis, it was not statistically significant.

CONCLUSIONS

Reduced expression of liver intestine-cadherin had a significant correlation with tumoral dedifferentiation and short overall survival in this series. In addition, early and frequent loss of liver intestine-cadherin expression might be a more sensitive indicator than E-cadherin to predict more aggressive tumoral behavior.

Association of mortalin (HSPA9) with liver cancer metastasis and prediction for early tumor recurrence

Hepatocellular carcinoma (HCC) is well known for poor prognosis and short survival because of high recurrence rate even after curative surgery. Today there is no available biomarker or biochemical test to indicate HCC recurrence, and this study aims to identify protein markers that can discriminate postoperative patients with early recurrence (ER), i.e. disease relapsed within the first year. In this study, 103 hepatitis B-related HCC patients were recruited, and 68 of them were used for ER-related biomarker discovery study. Proteomic expression patterns of matched tumor and adjacent non-tumor tissues from these patients plus 16 normal liver tissues were delineated by the two-dimensional gel electrophoresis differential profiling method. Significant protein spots were evaluated by hierarchical clustering analysis. SSP4612 that yielded the highest receiver operating characteristic (ROC) curve value for the ER subgroup of HCC was subsequently identified by tandem mass spectrometry, and the corresponding expression patterns were further confirmed by quantitative PCR, Western blot, and immunohistochemistry. Correlation analysis with clinicopathological data was also examined. Proteomic profiling analysis revealed overexpression of mortalin (gene HSPA9) in HCC when compared with the non-tumor and normal liver tissues (area under the curve (AUC) = 0.821). Furthermore, elevated mortalin level was also detected in the ER subgroup of HCC versus the recurrence-free state (where no cancer recurs for >1 year) (AUC = 0.833, sensitivity = 90.9%, specificity = 71.4%). Metastatic HCC cell lines also exhibited higher levels of mortalin and HSPA9 mRNA. Clinically, mortalin overexpression in HCC was closely associated with advanced tumor stages and venous infiltration, having implications for increased malignancy and aggressive behavior. Mortalin (HSPA9) is associated with HCC metastasis and thus suggested as a tumor marker for predicting early recurrence, which may have immediate clinical applications for cancer surveillance after curative surgery.