New markers of pancreatic cancer identified through differential gene expression analyses: claudin 18 and annexin A8. Am J Surg Pathol. 2008;32:188-196. [PMID: 18223320 DOI: 10.1097/pas.0b013e31815701f3]

The E3 ubiquitin ligase TRIP12 is required for pancreatic acinar cell plasticity and pancreatic carcinogenesis

The E3 ubiquitin ligase thyroid hormone receptor interacting protein 12 (TRIP12) has been implicated in pancreatic adenocarcinoma (PDAC) through its role in mediating the degradation of pancreas transcription factor 1a (PTF1a). PTF1a is a transcription factor essential for the acinar differentiation state that is notably diminished during the early steps of pancreatic carcinogenesis. Despite these findings, the direct involvement of TRIP12 in the onset of pancreatic cancer has yet to be established. In this study, we demonstrated that TRIP12 protein was significantly upregulated in human pancreatic preneoplastic lesions. Furthermore, we observed that TRIP12 overexpression varied within PDAC samples and PDAC-derived cell lines. We further demonstrated that TRIP12 was required for PDAC-derived cell growth and for the expression of E2F-targeted genes. Acinar-to-ductal cell metaplasia (ADM) is a reversible process that reflects the high plasticity of acinar cells. ADM becomes irreversible in the presence of oncogenic Kras mutations and leads to the formation of preneoplastic lesions. Using two genetically modified mouse models, we showed that a loss of TRIP12 prevented acini from developing ADM in response to pancreatic injury. With two additional mouse models, we further discovered that a depletion of TRIP12 prevented the formation of KrasG12D-induced preneoplastic lesions and impaired metastasis formation in the presence of mutated KrasG12D and Trp53R172H genes. In summary our study identified an overexpression of TRIP12 from the early stages of pancreatic carcinogenesis and proposed this E3 ubiquitin ligase as a novel regulator of acinar plasticity with an important dual role in initiation and metastatic steps of PDAC. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

The preclinical discovery and development of zolbetuximab for the treatment of gastric cancer

INTRODUCTION

Gastric cancer remains a formidable challenge in oncology with high mortality rates and few advancements in treatment. Claudin-18.2 (CLDN18.2) is a tight junction protein primarily expressed in the stomach and is frequently overexpressed in certain subsets of gastric cancers. Targeting CLDN18.2 with monoclonal antibodies, such as zolbetuximab (IMAB362), has shown promising efficacy results in combination with chemotherapy.

AREAS COVERED

The molecular cell biology of CLDN18.2 is discussed along with studies demonstrating the utility of CLDN18.2 expression as a biomarker and therapeutic target. Important clinical studies are reviewed, including Phase III trials, SPOTLIGHT and GLOW, which demonstrate the efficacy of zolbetuximab in combination with chemotherapy in patients with CLDN18.2-positive advanced gastric cancer.

EXPERT OPINION

CLDN18.2 is involved in gastric differentiation through maintenance of epithelial barrier function and coordination of signaling pathways, and its expression in gastric cancers reflects a 'gastric differentiation' program. Targeting Claudin-18.2 represents the first gastric cancer specific 'targeted' treatment. Further studies are needed to determine its role within current gastric cancer treatment sequencing, including HER2-targeted therapies and immunotherapies. Management strategies will also be needed to better mitigate zolbetuximab-related treatment side effects, including gastrointestinal (GI) toxicities.

Extent and clinical significance of the therapy-relevant tight junction protein Claudin 18.2 in pancreatic ductal adenocarcinoma - real-world evidence

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is associated with poor prognosis, wherefore targeted therapies have experienced increasing interest. Zolbetuximab is a novel targeted therapy under investigation in patients with PDAC and targets Claudin 18.2 (CLDN18.2), which is a component of tight junctions and is of significance in various solid tumors. As its role in PDAC is not definitively elucidated, this study aims to clarify the significance of CLDN18.2 expression in PDAC in a real-world setting.

METHODS

All patients (n = 309) were recruited at one of the PANCALYZE study centers and received pancreatic resection with curative intention. Paraffin samples were analyzed using an antibody against CLDN18.2, which is known to be comparable to the antibody used by the SPOTLIGHT and GLOW studies.

RESULTS

94 PDACs are positive for CLDN18.2 (30.4 %). Positive CLDN 18.2 expression was associated with significantly better cancer differentiation (p < 0.001). Patients with positive CLDN18.2 expression showed significantly better overall survival when compared to patients with negative expression (median OS: 30 versus 18 months, p = 0.003). Additionally, in multivariable analyses, CLDN18.2 expression was identified as an independent factor for better survival in patients with PDAC (HR = 0.686, 95 %CI = 0.492-0.956, p = 0.026).

CONCLUSION

Significant improvement in survival could be demonstrated by adding Zolbetuximab to known chemotherapy regimes in patients with gastro-esophageal junction adenocarcinoma with at least 75 % CLDN18.2 positive cancer cells. Our findings demonstrate, that 30.4 % of the included patients with PDAC would potentially be eligible for therapy with Zolbetuximab in a real-world patient cohort. Results of trials targeting Claudin 18.2 are pending in patients with PDAC.

Claudin 18.2 as a novel therapeutic target

Claudin 18.2, a tight-junction molecule predominantly found in the nonmalignant gastric epithelium, becomes accessible on the tumour cell surface during malignant transformation, thereby providing an appealing target for cancer therapy. Data from two phase III trials testing the anti-claudin 18.2 antibody zolbetuximab have established claudin 18.2-positive advanced-stage gastric cancers as an independent therapeutic subset that derives benefit from the addition of this agent to chemotherapy. This development has substantially increased the percentage of patients eligible for targeted therapy. Furthermore, newer treatments, such as high-affinity monoclonal antibodies, bispecific antibodies, chimeric antigen receptor T cells and antibody-drug conjugates capable of bystander killing effects, have shown considerable promise in patients with claudin 18.2-expressing gastric cancers. This new development has resulted from drug developers moving beyond traditional targets, such as driver gene alterations or growth factors. In this Review, we highlight the biological rationale and explore the clinical activity of therapies that target claudin 18.2 in patients with advanced-stage gastric cancer and explore the potential for expansion of claudin 18.2-targeted therapies to patients with other claudin 18.2-positive solid tumours.

Dark horse target Claudin18.2 opens new battlefield for pancreatic cancer

Pancreatic cancer is one of the deadliest malignant tumors, which is a serious threat to human health and life, and it is expected that pancreatic cancer may be the second leading cause of cancer death in developed countries by 2030. Claudin18.2 is a tight junction protein expressed in normal gastric mucosal tissues, which is involved in the formation of tight junctions between cells and affects the permeability of paracellular cells. Claudin18.2 is highly expressed in pancreatic cancer and is associated with the initiation, progression, metastasis and prognosis of cancer, so it is considered a potential therapeutic target. Up to now, a number of clinical trials for Claudin18.2 are underway, including solid tumors such as pancreatic cancers and gastric cancers, and the results of these trials have not yet been officially announced. This manuscript briefly describes the Claudia protein, the dual roles of Cluadin18 in cancers, and summarizes the ongoing clinical trials targeting Claudin18.2 with a view to integrating the research progress of Claudin18.2 targeted therapy. In addition, this manuscript introduces the clinical research progress of Claudin18.2 positive pancreatic cancer, including monoclonal antibodies, bispecific antibodies, antibody-drug conjugates, CAR-T cell therapy, and hope to provide feasible ideas for the clinical treatment of Claudin18.2 positive pancreatic cancer.

A bispecific antibody targeting HER2 and CLDN18.2 eliminates gastric cancer cells expressing dual antigens by enhancing the immune effector function

Gastric cancer (GC) is widely regarded as one of the toughest cancers to treat. Trastuzumab, which targets the human epidermal growth factor receptor 2 (HER2) for GC treatment, has demonstrated clinical success. However, these patients have a high likelihood of developing resistance. Additionally, Claudin18.2 (CLDN18.2) is a promising emerging target for GC treatment. Therefore, therapies that simultaneously target both HER2 and CLDN18.2 targets are of great significance. Here, we constructed a bispecific antibody targeting both HER2 and CLDN18.2 (HC-2G4S; BsAb), which displayed satisfactory purity, thermostability and enhancing antibody-dependent cell-mediated cytotoxicity (ADCC) activity. In a tumor spheroids model of GC, BsAb demonstrated greater therapeutic efficacy than monoclonal antibodies (mAb) or combination treatment strategies. We propose that the enhanced anti-tumor potency of BsAbs in vivo is due to the monovalent binding of single-chain antibodies to more targets due to weaker affinity, resulting in a more potent immune effect function. Therefore, HC-2G4S could be a productive agent for treating GC that is HER2-positive, CLDN18.2-positive, or both, with the potential to overcome trastuzumab resistance and provide significant clinical benefits and expanded indications.

Therapeutic Monoclonal Antibodies against Cancer: Present and Future

A series of monoclonal antibodies with therapeutic potential against cancer have been generated and developed. Ninety-one are currently used in the clinics, either alone or in combination with chemotherapeutic agents or other antibodies, including immune checkpoint antibodies. These advances helped to coin the term personalized medicine or precision medicine. However, it seems evident that in addition to the current work on the analysis of mechanisms to overcome drug resistance, the use of different classes of antibodies (IgA, IgE, or IgM) instead of IgG, the engineering of the Ig molecules to increase their half-life, the acquisition of additional effector functions, or the advantages associated with the use of agonistic antibodies, to allow a broad prospective usage of precision medicine successfully, a strategy change is required. Here, we discuss our view on how these strategic changes should be implemented and consider their pros and cons using therapeutic antibodies against cancer as a model. The same strategy can be applied to therapeutic antibodies against other diseases, such as infectious or autoimmune diseases.

An Update on the Role of Immunohistochemistry in the Evaluation of Pancreatic/Liver/Gastrointestinal Luminal Tract Disorders

CONTEXT.—

Immunohistochemistry serves as an ancillary diagnostic tool for a wide variety of neoplastic and nonneoplastic disorders, including infections, workup of inflammatory conditions, and subtyping neoplasms of the pancreas/liver/gastrointestinal luminal tract. In addition, immunohistochemistry is also used to detect a variety of prognostic and predictive molecular biomarkers for carcinomas of the pancreas, liver, and gastrointestinal luminal tract.

OBJECTIVE.—

To highlight an update on the role of immunohistochemistry in the evaluation of pancreatic/liver/gastrointestinal luminal tract disorders.

DATA SOURCES.—

Literature review and authors' research data and personal practice experience were used.

CONCLUSIONS.—

Immunohistochemistry is a valuable tool, assisting in the diagnosis of problematic tumors and benign lesions of the pancreas, liver, and gastrointestinal luminal tract, and also in the prediction of prognosis and therapeutic response for carcinomas of the pancreas, liver, and gastrointestinal luminal tract.

Expression patterns of claudins in cancer

Claudins are four-transmembrane proteins, which were found in tight junctions. They maintain cell barriers and regulate cell differentiation and proliferation. They are involved in maintaining cellular polarity and normal functions. Different claudins show different expression patterns. The expression level and localization of claudins are altered in various cancers. They promote or inhibit proliferation, invasion, and migration of cancer cells through multiple signaling pathways. Therefore, claudins may serve as diagnostic markers, novel therapeutic targets, and prognostic risk factors. The important roles of claudins in cancer aroused our great interest. In the present review, we provide a summary of insights into expression patterns of claudins in cancer, which is more comprehensive and provides new ideas for further research.

Preclinical characterization of an mRNA-encoded anti-Claudin 18.2 antibody

IMAB362/Zolbetuximab, a first-in-class IgG1 antibody directed against the cancer-associated gastric-lineage marker CLDN18.2, has recently been reported to have met its primary endpoint in two phase 3 trials as a first-line treatment in combination with standard of care chemotherapy in CLDN18.2-positive Her2 negative advanced gastric cancer. Here we characterize the preclinical pharmacology of BNT141, a nucleoside-modified RNA therapeutic encoding the sequence of IMAB362/Zolbetuximab, formulated in lipid nanoparticles (LNP) for liver uptake. We show that the mRNA-encoded antibody displays a stable pharmacokinetic profile in preclinical animal models, mediates CLDN18.2-restricted cytotoxicity comparable to IMAB362 recombinant protein and inhibits human tumor xenograft growth in immunocompromised mice. BNT141 administration did not perpetrate mortality, clinical signs of toxicity, or gastric pathology in animal studies. A phase 1/2 clinical trial with BNT141 mRNA-LNP has been initiated in advanced CLDN18.2-expressing solid cancers (NCT04683939).

Clinicopathological Features and Prognosis of Resected Pancreatic Ductal Adenocarcinoma Patients with Claudin-18 Overexpression

Claudin-18.2 (CLDN18.2) is specifically expressed in pancreatic precancerous lesions and pancreatic ductal adenocarcinoma (PDAC). We assessed the clinical characteristics of patients with CLDN18.2-overexpressing pancreatic cancer to identify patients who might benefit from CLDN18-targeted treatment. A total of 130 patients with surgically resected PDAC were investigated for the immunohistochemical expression of claudin-18 (CLDN18). The CLDN18 staining intensities (0-3+) and relative proportion of positive tumor cells were analyzed by two independent raters. Tumors positive for CLDN18 expression were defined as ≥80% of tumor cells with 2+ or 3+ staining intensity in a CLDN18 immunohistochemical assay. Positive CLDN18 expression was present in 41/130 (31.5%) surgically resected PDACs and the relative proportion of positive tumor cells and the staining intensity were directly correlated (p < 0.001). Positive CLDN18 expression was significantly associated with well-differentiated tumors (p < 0.001) and less regional node involvement (p = 0.045). The positive CLDN18-expressing group showed no statistical difference in median overall survival (17.4 months vs. 20.6 months, p = 0.770) compared to the negative CLDN18-expressing group. Distant nodal metastasis was more frequent in the positive CLDN18-expressing group (p = 0.011). CLDN18 is frequently expressed in PDAC, and high CLDN18-expressing PDACs showed some different clinicopathologic characteristics. High CLDN18 expression was not associated with prognosis in patients with surgically resected PDAC.

Integrated bioinformatics analysis of differentially expressed genes in the temporomandibular joint internal derangement

OBJECTIVES

This study aimed to identify significant mechanisms and potential treatments for temporomandibular joint internal derangement (TMJD) through integrated bioinformatics analysis.

MATERIALS AND METHODS

Gene expression data sets (GSE66864) from the Gene Expression Omnibus (GEO) database were downloaded. Differentially expressed genes (DEGs) were identified both in the treatment groups and in controls by R packages. Network analysis of protein-protein interaction (PPI) and Human Protein Atlas was used to explore DEGs' potential function. DGIdb database was utilized to gain potential drug targets.

RESULTS

In conclusion, 126 DEGs were selected for TMJD through bioinformatics analysis. Both GO and Kyoto Encyclopedia of Genes and Genomes analyses combined showed the pathways involved in TMJD. A PPI network was constructed to select the top 10 hub genes, of which five hub genes were chosen for further investigation. Moreover, the microenvironment of immune cells related to hub genes was evaluated by R packages. Macrophages play an important role in inflammation and oral-related tumors. The Human Protein Atlas analysis indicated that the five hub genes are highly related to head and neck cancer. Finally, eight potential drugs were selected for two genes using the DGIdb database.

CONCLUSION

Our integrated bioinformatics analysis identified DEGs in TMJD and provided potential ideas for further research and treatment approaches. However, experimental validation of the hub genes and potential drug targets is still needed. The key mechanisms of the identified genes and their potential roles as biomarkers or drug targets in TMJD require further investigation.

Claudin and pancreatic cancer

Due to the lack of timely and accurate screening modalities and treatments, most pancreatic cancer (PCa) patients undergo fatal PCa progression within a short period since diagnosis. The claudin(CLDN) family is expressed specifically as tight junction structure in a variety of tumors, including PCa, and affects tumor progression by changing the cell junctions. Thus far, many of the 27 members of the claudin family, including claudin-18.2 and claudin-4, have significantly aberrantly expression in pancreatic tumors. In addition, some studies have confirmed the role of some claudin proteins in the diagnosis and treatment of pancreatic tumors. By targeting different targets of claudin protein and combining chemotherapy, further enhance tumor cell necrosis and inhibit tumor invasion and metastasis. Claudins can either promote or inhibit the development of pancreatic cancer, which indicates that the diagnosis and treatment of different kinds of claudins require to consider different biological characteristics. This literature summarizes the functional characteristics and clinical applications of various claudin proteins in Pca cells, with a focus on claudin-18.2 and claudin-4.

Pathobiological functions and clinical implications of annexin dysregulation in human cancers

Annexins are an extensive superfamily of structurally related calcium- and phospholipid-binding proteins, largely conserved and widely distributed among species. Twelve human annexins have been identified, referred to as Annexin A1-13 (A12 remains as of yet unassigned), whose genes are spread throughout the genome on eight different chromosomes. According to their distinct tissue distribution and subcellular localization, annexins have been functionally implicated in a variety of biological processes relevant to both physiological and pathological conditions. Dysregulation of annexin expression patterns and functions has been revealed as a common feature in multiple cancers, thereby emerging as potential biomarkers and molecular targets for clinical application. Nevertheless, translation of this knowledge to the clinic requires in-depth functional and mechanistic characterization of dysregulated annexins for each individual cancer type, since each protein exhibits varying expression levels and phenotypic specificity depending on the tumor types. This review specifically and thoroughly examines the current knowledge on annexin dysfunctions in carcinogenesis. Hence, available data on expression levels, mechanism of action and pathophysiological effects of Annexin A1-13 among different cancers will be dissected, also further discussing future perspectives for potential applications as biomarkers for early diagnosis, prognosis and molecular-targeted therapies. Special attention is devoted to head and neck cancers (HNC), a complex and heterogeneous group of aggressive malignancies, often lately diagnosed, with high mortality, and scarce therapeutic options.

Development of a Humanized VHH Based Recombinant Antibody Targeting Claudin 18.2 Positive Cancers

Claudin 18.2 (CLDN18.2), a tight junction (TJ) family protein controlling molecule exchange between cells, is frequently over-expressed in gastric cancer, pancreatic adenocarcinomas and in a fraction of non–small cell lung cancer cases. The tumor properties indicate that CLDN18.2 could be an attractive drug target for gastric and pancreatic cancers. In this study, we present effective strategies for developing anti-CLDN18.2 therapeutic candidates, based on variable domain of heavy chain of heavy chain antibodies (VHHs). CLDN18.2-specific VHHs were isolated by panning a phage display library from an alpaca immunized with a stable cell line highly expressing CLDN18.2. Humanized VHHs fused with human IgG1 Fc, as potential therapeutic candidates, exhibited desirable binding specificity and affinity to CLDN18.2. In vitro experiments showed that hu7v3-Fc was capable of eliciting both antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) on CLDN18.2 positive tumor cells. In the mouse xenograft model, the anti-tumor efficacy of hu7v3-Fc was significantly more potent than Zolbetuximab, the benchmark anti-CLDN18.2 monoclonal antibody. Moreover, in vivo biodistribution using zirconium-89 (⁸⁹Zr) labeled antibodies demonstrated that hu7v3-Fc (⁸⁹Zr-hu7v3-Fc) exhibited a better tumor penetration and a faster tumor uptake than Zolbetuximab (⁸⁹Zr-Zolbetuximab), which might be attributed to its smaller size and higher affinity. Taken together, anti-CDLN18.2 hu7v3-Fc is a promising therapeutic agent for human CLDN18.2 positive cancers. Furthermore, hu7v3 has emerged as a potential module for novel CLDN18.2 related therapeutics.

Claudin18.2 is a novel molecular biomarker for tumor-targeted immunotherapy

The claudin18.2 (CLDN18.2) protein, an isoform of claudin18, a member of the tight junction protein family, is a highly selective biomarker with limited expression in normal tissues and often abnormal expression during the occurrence and development of various primary malignant tumors, such as gastric cancer/gastroesophageal junction (GC/GEJ) cancer, breast cancer, colon cancer, liver cancer, head and neck cancer, bronchial cancer and non-small-cell lung cancer. CLDN18.2 participates in the proliferation, differentiation and migration of tumor cells. Recent studies have identified CLDN18.2 expression as a potential specific marker for the diagnosis and treatment of these tumors. With its specific expression pattern, CLDN18.2 has become a unique molecule for targeted therapy in different cancers, especially in GC; for example, agents such as zolbetuximab (claudiximab, IMAB362), a monoclonal antibody (mAb) against CLDN18.2, have been developed. In this review, we outline recent advances in the development of immunotherapy strategies targeting CLDN18.2, including monoclonal antibodies (mAbs), bispecific antibodies (BsAbs), chimeric antigen receptor T (CAR-T) cells redirected to target CLDN18.2, and antibody–drug conjugates (ADCs).

Claudin-18.2 as a therapeutic target in cancers: cumulative findings from basic research and clinical trials

Claudins are major components of tight junctions that maintain cell polarity and intercellular adhesion. The dynamics of claudins in cancer cells have attracted attention as a therapeutic target. During carcinogenesis, claudin expression is generally downregulated; however, overexpression of claudin-18.2 has been observed in several types of cancers. Upregulated and mislocalized claudin-18.2 expression in cancer cells has been suggested as a therapeutic target. Research on claudin-18.2 has revealed its involvement in carcinogenesis. Clinical trials using zolbetuximab, a monoclonal antibody targeting claudin-18.2, for patients with advanced cancer yielded positive results with few high-grade adverse events; thus, it is expected to be a novel and effective therapeutic. Here, we review current insights into the role that claudin-18.2 plays in basic cancer research and clinical applications. A better understanding of these roles will facilitate the development of new treatment strategies for cancer patients with poor prognoses.

Claudin-18 expression in small bowel adenocarcinoma: a clinico-pathologic study

Non-ampullary small bowel adenocarcinoma is a rare neoplasm with an ominous prognosis, whose incidence is higher in some chronic immuno-inflammatory conditions, such as coeliac and Crohn's disease. Recently, claudin 18.2, a transmembrane protein normally expressed in gastric mucosa, has been recognized as a novel pan-cancer therapeutic target, and several clinical trials with claudin-18-directed drugs have shown promising results on various gastrointestinal malignancies. This is the first study focusing on claudin-18 expression in small bowel adenocarcinomas. The immunohistochemical expression of claudin-18 (clone 43-14A) was assessed in 81 small bowel adenocarcinomas of diverse aetiologies and correlated with several clinico-pathologic features and patient survival. We found that 28% of adenocarcinomas were immunoreactive for claudin-18, with cutoff values of ≥1% at any intensity, while 6% of cancers showed immunoexpression of ≥75% with 2+/3+ score. Moreover, claudin-18 (≥1%) was positively associated with cytokeratin 7 (CK7) and MUC5AC expression, showing CK7+/MUC5AC+ carcinomas the highest rate of positive cases, whereas a negative correlation was found between claudin-18 and CDX2 expression. In addition, some cancer-adjacent dysplastic growths and foci of gastric-type metaplasia in Crohn's disease-associated cases showed claudin-18 immunoreactivity. Survival analysis showed a non-significant trend towards a worse cancer-specific survival for claudin-18-positive cases. A fraction of small bowel adenocarcinomas, mainly sporadic or Crohn's disease-associated, and often exhibiting a non-intestinal immunoprofile, expressed claudin-18, suggesting that claudin-18-directed targeted therapy is worth investigating in such cancers.

An Ultrastable Virus-Like Particle with a Carbon Dot Core and Expanded Sequence Plasticity

Ordered bio-inorganic hybridization has evolved for the generation of high-performance materials in living organisms and inspires novel strategies to design artificial hybrid materials. Virus-like particles (VLPs) are attracting extensive interest as self-assembling systems and platforms in the fields of biotechnology and nanotechnology. However, as soft nanomaterials, their structural stability remains a general and fundamental problem in various applications. Here, an ultrastable VLP assembled from the major capsid protein (VP1) of simian virus 40 is reported, which contains a carbon dot (C-dot) core. Co-assembly of VP1 with C-dots led to homogeneous T = 1 VLPs with a fourfold increase in VLP yields. The resultant hybrid VLPs showed markedly enhanced structural stability and sequence plasticity. C-dots and a polyhistidine tag fused to the inner-protruding N-terminus of VP1 contributed synergistically to these enhancements, where extensive and strong noncovalent interactions on the C-dot/VP1 interfaces are responsible according to cryo-EM 3D reconstruction, molecular simulation, and affinity measurements. C-dot-enhanced ultrastable VLPs can serve as a new platform, enabling the fabrication of new architectures for bioimaging, theranostics, nanovaccines, etc. The hybridization strategy is simple and can easily be extended to other VLPs and protein nanoparticle systems.

miR-185-3p targets Annexin-A8 to inhibit proliferation in cervical cancer cells

Numerous studies have found that microRNAs (miRNAs) are involved in regulating various tumor-related biological functions. The downregulation of miR185-3p have been identified in various types of cancer but the effect and its underlying molecular mechanism in cervical cancer have not been elucidated. Therefore, it is important to investigate the role of miRNAs associated with cervical cancer and its corresponding molecular mechanism to develop new therapeutic targets. The cell counting kit (CCK-8) assay was performed to measure the cell viability. The quantitative real-time PCR (qRT-PCR) and western blot analyses were carried out to identify mRNA and protein expression levels, respectively. Besides, a luciferase activity assay was conducted to confirm the target miRNA gene predictions. In this study, it is found that miR185-3p expression was potentially downregulated in cervical cancer tissues when compared with normal tissues. The CCK-8 results indicated that miR185-3p overexpression suppressed the cancer cell proliferation and the downregulation of miR185-3p enhanced the cancer cell growth. Further, enhanced miR185-3p expression led to a reduction in Annexin-A8 (Anx-A8) expression but miR185-3p inhibition promoted ANX-A8 levels in cervical cancer cells. The luciferase reporter assay indicated that ANX-A8 was a direct target of miR185-3p in cervical cancer cells.

Stroma Involvement in Pancreatic Ductal Adenocarcinoma: An Overview Focusing on Extracellular Matrix Proteins

Pancreatic cancer is the seventh leading cause of cancer-related deaths worldwide and is predicted to become second in 2030 in industrialized countries if no therapeutic progress is made. Among the different types of pancreatic cancers, Pancreatic Ductal Adenocarcinoma (PDAC) is by far the most represented one with an occurrence of more than 90%. This specific cancer is a devastating malignancy with an extremely poor prognosis, as shown by the 5-years survival rate of 2–9%, ranking firmly last amongst all cancer sites in terms of prognostic outcomes for patients. Pancreatic tumors progress with few specific symptoms and are thus at an advanced stage at diagnosis in most patients. This malignancy is characterized by an extremely dense stroma deposition around lesions, accompanied by tissue hypovascularization and a profound immune suppression. Altogether, these combined features make access to cancer cells almost impossible for conventional chemotherapeutics and new immunotherapeutic agents, thus contributing to the fatal outcomes of the disease. Initially ignored, the Tumor MicroEnvironment (TME) is now the subject of intensive research related to PDAC treatment and could contain new therapeutic targets. In this review, we will summarize the current state of knowledge in the field by focusing on TME composition to understand how this specific compartment could influence tumor progression and resistance to therapies. Attention will be paid to Tenascin-C, a matrix glycoprotein commonly upregulated during cancer that participates to PDAC progression and thus contributes to poor prognosis.

Role of tight junctions in the epithelial-to-mesenchymal transition of cancer cells

The epithelial-mesenchymal transition (EMT) is an essential step in cancer progression. Epithelial cells possess several types of cell-cell junctions, and tight junctions are known to play important roles in maintaining the epithelial program. EMT is characterized by a loss of epithelial markers, including E-cadherin and tight junction proteins. Somewhat surprisingly, the evidence is accumulating that upregulated expression of tight junction proteins plays an important role in the EMT of cancer cells. Tight junctions have distinct tissue-specific and cancer-specific regulatory mechanisms, enabling them to play different roles in EMT. Tight junctions and related signaling pathways are attractive targets for cancer treatments; signal transduction inhibitors and monoclonal antibodies for tight junction proteins may be used to suppress EMT, invasion, and metastasis. Here we review the role of bicellular and tricellular tight junction proteins during EMT. Further investigation of regulatory mechanisms of tight junctions during EMT in cancer cells will inform the development of biomarkers for predicting prognosis as well as novel therapies.

Emerging Cancer Epigenetic Mechanisms Regulated by All-Trans Retinoic Acid

All-trans retinoic acid (RA), which is the dietary bioactive derivative obtained from animal (retinol) and plant sources (beta-carotene), is a physiological lipid signal of both embryonic and postembryonic development. During pregnancy, either RA deficiency or an excessive RA intake is teratogenic. Too low or too high RA affects not only prenatal, but also postnatal, developmental processes such as myelopoiesis and mammary gland morphogenesis. In this review, we mostly focus on emerging RA-regulated epigenetic mechanisms involving RA receptor alpha (RARA) and Annexin A8 (ANXA8), which is a member of the Annexin family, as well as ANXA8 regulatory microRNAs (miRNAs). The first cancer showing ANXA8 upregulation was reported in acute promyelocytic leukemia (APL), which induces the differentiation arrest of promyelocytes due to defective RA signaling caused by RARA fusion genes as the PML-RARA gene. Over the years, ANXA8 has also been found to be upregulated in other cancers, even in the absence of RARA fusion genes. Mechanistic studies on human mammary cells and mammary glands of mice showed that ANXA8 upregulation is caused by genetic mutations affecting RARA functions. Although not all of the underlying mechanisms of ANXA8 upregulation have been elucidated, the interdependence of RA-RARA and ANXA8 seems to play a relevant role in some normal and tumorigenic settings.

Prognostic Value of ANXA8 in Gastric Carcinoma

Gastric carcinoma (GC) remains one of the most common and deadly cancers worldwide. In China, the incidence and mortality rates related to GC were quite high. Annexin A8 (ANXA8) is a member of the annexins family of calcium-dependent membrane phospholipid binding proteins. According to recent research, the up-regulation of ANXA8 is closely associated with various types of tumors. However, the specific role of ANXA8 in GC remains unclear. In our study, we explored the prognostic value of ANXA8 in GC. Here, with the data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets (GSE19826 and GSE13861) analyzed, we further performed quantitative real-time polymerase chain reaction (qRT-PCR) using 58 pairs of fresh-frozen tissues. We also subjected 152 pairs of formalin-fixed, paraffin-embedded GC tumor tissues from patients, and the adjacent normal gastric tissues (ANGTs) to immunohistochemical (IHC) analysis. Hence, we found an elevated expression of ANXA8 in tumor tissues with bioinformatics analyses, qRT-PCR, western blot and IHC. Over-expression of ANXA8 was strongly correlated with TNM stages and differentiation grades. Kaplan-Meier and cox proportional-hazard analyses showed that the increased expression of ANXA8 was strongly associated with overall survival (OS) and disease-free survival (DFS) in GC patients. Moreover, we found that ANXA8 is an independent prognostic factor of GC patients' OS and DFS. In brief, those results suggest that ANXA8 can act as an oncogene of GC development and can serve as a potential prognostic biomarker for GC treatment.

Comparison of Claudin 18.2 expression in primary tumors and lymph node metastases in Japanese patients with gastric adenocarcinoma

BACKGROUND

The monoclonal antibody zolbetuximab (formerly IMAB362), which is being developed as a potential treatment for gastric cancer (GC), targets Claudin 18.2 (CLDN18.2), a GC biomarker. This study aimed to determine the prevalence of CLDN18.2 in primary tumors and lymph node (LN) metastases of Japanese patients with GC.

METHODS

CLDN18.2 expression was investigated in tissue samples from patients with gastric adenocarcinoma archived at Kurume University Medical Center, Japan, between 2000 and 2012. Expression of CLDN18.2 in tumor samples was evaluated by immunohistochemistry using the same detection antibody (43-14A) and assay used in the FAST clinical trial (NCT01630083), a phase 2 randomized trial that compared the safety and antitumor activity of the zolbetuximab-chemotherapy combination with chemotherapy alone. Samples showing any specific staining with ≥1+ intensity were defined as CLDN18.2-positive.

RESULTS

Of 263 samples analyzed (134 primary gastric tumors and corresponding LN metastases; 128 primary tumors only; one LN metastases only), CLDN18.2 was detected in 87% (n = 228/262) of all primary tumors and 80% (n = 108/135) of LN metastases. Moderate-to-strong CLDN18.2 expression (≥2+ membrane staining intensity in ≥40% of tumor cells [FAST eligibility criterion]) was observed in 52% (n = 135/262) of primary tumors and 45% (n = 61/135) of (LN) metastases. CLDN18.2 expression was significantly higher in GCs of the diffuse histological subtype per Lauren classification and in high grade (G3) tumors.

CONCLUSIONS

The high prevalence of CLDN18.2 among Japanese patients with GC supports the therapeutic assessment of zolbetuximab in this population.

Tight Junctions in Cell Proliferation

Tight junction (TJ) proteins form a continuous intercellular network creating a barrier with selective regulation of water, ion, and solutes across endothelial, epithelial, and glial tissues. TJ proteins include the claudin family that confers barrier properties, members of the MARVEL family that contribute to barrier regulation, and JAM molecules, which regulate junction organization and diapedesis. In addition, the membrane-associated proteins such as MAGUK family members, i.e., zonula occludens, form the scaffold linking the transmembrane proteins to both cell signaling molecules and the cytoskeleton. Most studies of TJ have focused on the contribution to cell-cell adhesion and tissue barrier properties. However, recent studies reveal that, similar to adherens junction proteins, TJ proteins contribute to the control of cell proliferation. In this review, we will summarize and discuss the specific role of TJ proteins in the control of epithelial and endothelial cell proliferation. In some cases, the TJ proteins act as a reservoir of critical cell cycle modulators, by binding and regulating their nuclear access, while in other cases, junctional proteins are located at cellular organelles, regulating transcription and proliferation. Collectively, these studies reveal that TJ proteins contribute to the control of cell proliferation and differentiation required for forming and maintaining a tissue barrier.

Pancreatic duct-like cell line derived from pig embryonic stem cells: expression of uroplakin genes in pig pancreatic tissue

The isolation of a cell line, PICM-31D, with phenotypic characteristics like pancreatic duct cells is described. The PICM-31D cell line was derived from the previously described pig embryonic stem cell-derived exocrine pancreatic cell line, PICM-31. The PICM-31D cell line was morphologically distinct from the parental cells in growing as a monolayer rather than self-assembling into multicellular acinar-like structures. The PICM-31D cells were propagated for over a year at split ratios of 1:3 to 1:10 at each passage without change in phenotype or growth rate. Electron microscopy showed the cells to be a polarized epithelium of cuboidal cells joined by tight junction-like adhesions at their apical/lateral aspect. The cells contained numerous mucus-like secretory vesicles under their apical cell membrane. Proteomic analysis of the PICM-31D's cellular proteins detected MUC1 and MUC4, consistent with mucus vesicle morphology. Gene expression analysis showed the cells expressed pancreatic ductal cell-related transcription factors such as GATA4, GATA6, HES1, HNF1A, HNF1B, ONECUT1 (HNF6), PDX1, and SOX9, but little or no pancreas progenitor cell markers such as PTF1A, NKX6-1, SOX2, or NGN3. Pancreas ductal cell-associated genes including CA2, CFTR, MUC1, MUC5B, MUC13, SHH, TFF1, KRT8, and KRT19 were expressed by the PICM-31D cells, but the exocrine pancreas marker genes, CPA1 and PLA2G1B, were not expressed by the cells. However, the exocrine marker, AMY2A, was still expressed by the cells. Surprisingly, uroplakin proteins were prominent in the PICM-31D cell proteome, particularly UPK1A. Annexin A1 and A2 proteins were also relatively abundant in the cells. The expression of the uroplakin and annexin genes was detected in the cells, although only UPK1B, UPK3B, ANXA2, and ANXA4 were detected in fetal pig pancreatic duct tissue. In conclusion, the PICM-31D cell line models the mucus-secreting ductal cells of the fetal pig pancreas.

Characterization of zolbetuximab in pancreatic cancer models

In healthy tissue, the tight junction protein Claudin 18.2 (CLDN18.2) is present only in the gastric mucosa. Upon malignant transformation of gastric epithelial tissue, perturbations in cell polarity lead to cell surface exposure of CLDN18.2 epitopes. Moreover, CLDN18.2 is aberrantly expressed in malignancies of several other organs, such as pancreatic cancer (PC). A monoclonal antibody, zolbetuximab (formerly known as IMAB362), has been generated against CLDN18.2. In a phase 2 clinical trial (FAST: NCT01630083), zolbetuximab in conjunction with chemotherapy prolonged overall and progression-free survival over chemotherapy alone and improved quality of life. In this study, the mechanism of action and antitumor activity of zolbetuximab were investigated using nonclinical PC models. Zolbetuximab bound specifically and with strong affinity to human PC cells that expressed CLDN18.2 on the cell surface. In ex vivo systems using immune effector cells and serum from healthy donors, zolbetuximab induced antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), resulting in the lysis of cultured human PC cells. The amplitude of ADCC and CDC directly correlated with cell surface CLDN18.2 levels. The chemotherapeutic agent gemcitabine upregulated CLDN18.2 expression in cultured human PC cells and enhanced zolbetuximab-induced ADCC. In mouse xenograft tumors derived from human PC cell lines, including gemcitabine-refractory ones, zolbetuximab slowed tumor growth, benefited survival, and attenuated metastases development. The results presented here validate CLDN18.2 as a targetable biomarker in PC and support extension of the clinical development of zolbetuximab to patients with CLDN18.2-expressing PC.

Quantitative proteomic analysis of pancreatic cyst fluid proteins associated with malignancy in intraductal papillary mucinous neoplasms

Background

The application of advanced imaging technologies for identifying pancreatic cysts has become widespread. However, accurately differentiating between low-grade dysplasia (LGD), high-grade dysplasia (HGD), and invasive intraductal papillary mucinous neoplasms (IPMNs) remains a diagnostic challenge with current biomarkers, necessitating the development of novel biomarkers that can distinguish IPMN malignancy.

Methods

Cyst fluid samples were collected from nine IPMN patients (3 LGD, 3 HGD, and 3 invasive IPMN) during their pancreatectomies. An integrated proteomics approach that combines filter-aided sample preparation, stage tip-based high-pH fractionation, and high-resolution MS was applied to acquire in-depth proteomic data of pancreatic cyst fluid and discover marker candidates for IPMN malignancy. Biological processes of differentially expressed proteins that are related to pancreatic cysts and aggressive malignancy were analyzed using bioinformatics tools such as gene ontology analysis and Ingenuity pathway analysis. In order to confirm the validity of the marker candidates, 19 cyst fluid samples were analyzed by western blot.

Results

A dataset of 2992 proteins was constructed from pancreatic cyst fluid samples. A subsequent analysis found 2963 identified proteins in individual samples, 2837 of which were quantifiable. Differentially expressed proteins between histological grades of IPMN were associated with pancreatic diseases and malignancy according to ingenuity pathway analysis. Eighteen biomarker candidates that were differentially expressed across IPMN histological grades were discovered—7 DEPs that were upregulated and 11 that were downregulated in more malignant grades. HOOK1 and PTPN6 were validated by western blot in an independent cohort, the results of which were consistent with our proteomic data.

Conclusions

This study demonstrates that novel biomarker candidates for IPMN malignancy can be discovered through proteomic analysis of pancreatic cyst fluid.

Electronic supplementary material

The online version of this article (10.1186/s12014-018-9193-1) contains supplementary material, which is available to authorized users.

Transcriptomic and histopathological analysis of cholangiolocellular differentiation trait in intrahepatic cholangiocarcinoma

BACKGROUND & AIMS

Intrahepatic cholangiocarcinoma (iCCA) is a heterogeneous entity with diverse aetiologies, morphologies and clinical outcomes. Recently, histopathological distinction of cholangiolocellular differentiation (CD) of iCCA has been suggested. However, its genome-wide molecular features and clinical significance remain unclear.

METHODS

Based on CD status, we stratified iCCAs into iCCA with CD (n=20) and iCCA without CD (n=102), and performed an integrative analysis using transcriptomic and clinicopathological profiles.

RESULTS

iCCA with CD revealed less aggressive histopathological features compared to iCCA without CD, and iCCA with CD showed favourable clinical outcomes of overall survival and time to recurrence than iCCA without CD (P<.05 for all). Transcriptomic profiling revealed that iCCA with CD resembled an inflammation-related subtype, while iCCA without CD resembled a proliferation subtype. In addition, we identified a CD signature that can predict prognostic outcomes of iCCA (CD_UP, n=486 and CD_DOWN, n=308). iCCAs were subgrouped into G1 (positivity for CRP and CDH2, 7%), G3 (positivity for S100P and TFF1, 32%) and G2 (the others, 61%). Prognostic outcomes for overall survival (P=.001) and time to recurrence (P=.017) were the most favourable in G1-iCCAs, intermediate in G2-iCCAs and the worst in G3-iCCAs. Similar result was confirmed in the iCCA set from GSE26566 (n=68).

CONCLUSIONS

CD signature was identified to predict the prognosis of iCCA. The combined evaluation of histology of CD and protein expression status of CRP, CDH2, TFF1 and S100P might help subtyping and predicting clinical outcomes of iCCA.

IL2RG, identified as overexpressed by RNA-seq profiling of pancreatic intraepithelial neoplasia, mediates pancreatic cancer growth

Pancreatic ductal adenocarcinoma evolves from precursor lesions, the most common of which is pancreatic intraepithelial neoplasia (PanIN). We performed RNA-sequencing analysis of laser capture microdissected PanINs and normal pancreatic duct cells to identify differentially expressed genes between PanINs and normal pancreatic duct, and between low-grade and high-grade PanINs. One of the most highly overexpressed transcripts identified in PanIN is interleukin-2 receptor subunit gamma (IL2RG) encoding the common gamma chain, IL2Rγ. CRISPR-mediated knockout of IL2RG in orthotopically implanted pancreatic cancer cells resulted in attenuated tumor growth in mice and reduced JAK3 expression in orthotopic tumors. These results indicate that IL2Rγ/JAK3 signaling contributes to pancreatic cancer cell growth in vivo.

Annexin A8 is a novel molecular marker for detecting lymph node metastasis in oral squamous cell carcinoma

Cervical lymph node metastasis is an important prognostic factor in oral squamous cell carcinoma (OSCC), but its accurate assessment after sentinel node biopsy or neck dissection is often limited to the histopathological examination of only one or two sections. Previous our study showed the usefulness of the reverse transcription loop-mediated isothermal amplification (RT-LAMP) targeting keratin 19 (KRT19) mRNA for the genetic detection of lymph node metastasis, but the sensitivity was insufficient. Here, we have attempted to identify novel molecular markers for OSCC cells in lymph nodes. We performed microarray analysis to identify genes overexpressed in 7 metastatic lymph nodes from OSCC patients, compared to 1 normal lymph node and 5 salivary glands from non-cancer patients. We then used real-time quantitative RT-PCR (qRT-PCR) and RT-LAMP to compare the expression of these genes in newly resected metastatic and normal lymph nodes. Of 4 genes identified by microarray analysis, annexin A8 (ANXA8) and desmoglein 3 mRNA were detected by qRT-PCR in metastatic lymph nodes but not in normal lymph nodes. Furthermore, ANXA8 mRNA expression was detected in all KRT19-negative metastatic lymph nodes. Both KRT19 and ANXA8 mRNA may be useful markers for detecting lymph node metastases in OSCC patients.

Pancreatic Ductal Adenocarcinoma and Its Variants

Pancreatic cancer represents the seventh leading cause of cancer death in the world, responsible for more than 300,000 deaths per year. The most common tumor type among pancreatic cancers is pancreatic ductal adenocarcinoma, an infiltrating neoplasm with glandular differentiation that is derived from pancreatic ductal tree. Here we present and discuss the most important macroscopic, microscopic, and immunohistochemical characteristics of this tumor, highlighting its key diagnostic features. Furthermore, we present the classic features of the most common variants of pancreatic ductal adenocarcinoma. Last, we summarize the prognostic landscape of this highly malignant tumor and its variants.

Nuclear localization of tricellulin promotes the oncogenic property of pancreatic cancer

Accumulating evidence has shown that dysregulation of tight junctions (TJs) is involved in tumor development and progression. In this study, we investigated the expression and subcellular distribution of tricellulin, which constitutes tricellular TJs, using human pancreatic adenocarcinomas. In well-differentiated pancreatic adenocarcinoma tissues, tricellulin immunostaining was prominent in the cytoplasm and the plasma membrane. In contrast, in poorly differentiated tissues, its immunostaining was predominantly observed in the nuclei and was almost absent in the plasma membrane. The distinct immunostaining of tricellulin successfully distinguished poorly differentiated adenocarcinoma from moderately and well-differentiated adenocarcinomas with high levels of sensitivity and specificity. Nuclear tricellulin expression significantly correlated with lymph node metastasis, lymphatic invasion and poor survival. In pancreatic cancer cell lines, tricellulin localization shifted from the membrane to nucleus with decreasing differentiation status. Nuclear localization of tricellulin promoted cell proliferation and invasiveness possibly in association with MAPK and PKC pathways in pancreatic cancers. Our results provide new insights into the function of tricellulin, and its nuclear localization may become a new prognostic factor for pancreatic cancers.

Roles of the first-generation claudin binder, Clostridium perfringens enterotoxin, in the diagnosis and claudin-targeted treatment of epithelium-derived cancers

Given that most malignant tumors are derived from epithelium, developing a strategy for treatment of epithelium-derived cancers (i.e., carcinomas) is a pivotal issue in cancer therapy. Carcinomas, including ovarian, breast, prostate, and pancreatic cancers, are known to overexpress various claudins (CLDNs); in particular, CLDN-3 and -4 are frequently overexpressed in malignant case. The generation of CLDN binders is a key for expanding CLDN-targeted cancer therapy but has been delayed due to the small size of CLDN extracellular domains (approximately 50 amino acids for the first domain and 15 amino acids for the second) and their high homology among species. Interestingly, however, the receptors for Clostridium perfringens enterotoxin (CPE), a foodborne toxin in humans, happen to be identical to CLDN-3 and -4. Thus, the first CLDN binder, CPE, has provided us CLDN-targeted cancer therapy from a concept into a potential reality. In this review, we describe roles of CPE technology in cancer therapy and discuss future directions in the CLDN-targeting concept-to-therapy process.

Addiction of pancreatic cancer cells to zinc-finger transcription factor ZIC2

Activity of GLI transcription factors of Hedgehog signaling is key for various cancer cell properties, especially in pancreatic ductal adenocarcinoma (PDAC). Zinc-finger transcriptional regulators ZIC1 to ZIC5 of ZIC gene family were demonstrated to associate with GLI to increase the nuclear accumulation and transcriptional activity of GLI. Notwithstanding this supportive role for GLI-dependent transcription, it was not fully understood whether ZIC plays an independent role in cancer cell biology. Here, we found that ZIC2 is indispensable in the regulation of PDAC cell apoptosis. We found that human PDAC cell lines uniquely express ZIC2. ZIC2 knockdown induced PDAC cell apoptosis; conversely, ZIC2 over-expression enhanced the cellular proliferation. Through a comprehensive screening, we identified fibroblast growth factor receptor 3 (FGFR3) and ANNEXIN A8 (ANXA8) as genes up-regulated by ZIC2 in PDAC cells. The forced expression of these two genes cooperatively rescued the apoptosis of ZIC2-knockdown cells. Immunohistochemical analyses further supported the correlation of ZIC2 expression and these genes in human pancreata harboring PDAC. Intriguingly, the ZIC2-mediated up-regulation of FGFR3 and ANXA8 was indicated to be GLI -independent. This evidence highlights the indispensable role of ZIC2 in regulating cellular proliferation and apoptosis during PDAC development and suggests a potential therapeutic target for PDAC.

Diagnostic value of IMP3 and mesothelin in differentiating pancreatic ductal adenocarcinoma from chronic pancreatitis

BACKGROUND

The discrimination between pancreatic ductal adenocarcinoma (PDA) and chronic pancreatitis may be confusing at both clinical and radiologic levels. So, the search for biomarkers able to distinguish both clinical conditions is of great interest.

AIM

This study was undertaken to assess the value of insulin-like growth factor II mRNA binding protein 3 (IMP3) and mesothelin to differentiate PDA from non-neoplastic/reactive pancreatic duct epithelium.

METHODS

Immunohistochemical staining for IMP3 and mesothelin was performed on 40 formalin-fixed, paraffin-embedded tissue sections of PDA, 20 biopsies of chronic pancreatitis and 10 normal pancreatic tissue obtained from tumor-free surgical margins. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy were calculated.

RESULTS

IMP3 immunoreactivity was observed in 34 of 40 (85%) cases of PDA. The staining reaction was moderate to strong in 30 (75%) cases and diffuse in 26 (65%) cases. Eighteen of 20 (90%) biopsies of chronic pancreatitis were negative for IMP3, while the other two cases (10%) showed weak and focal IMP3 immunoreactivity. On the other hand, mesothelin demonstrated positive immunoreactivity in 30 of 40 (75%) cases of PDA. The staining reaction was moderate to strong in 24 (60%) cases and diffuse in 22 (55%) cases. Sixteen of 20 (80%) biopsies of chronic pancreatitis were negative for mesothelin, while weak and focal mesothelin staining was detected in the other 4 cases. All normal pancreatic tissues were negative for IMP3 and mesothelin expression. IMP3 showed higher sensitivity (85%) and specificity (90%) than mesothelin (75% and 80%, respectively).

CONCLUSIONS

Our results showed that IMP3 immunostaining has a higher sensitivity and specificity than mesothelin for the diagnosis of PDA. IMP3 and mesothelin may be useful markers in distinguishing neoplastic from reactive lesions of the pancreas in instances where this is impossible by morphology alone in surgical pathology practice.

Expression pattern and prognostic significance of claudin 1, 4 and 7 in pancreatic cancer

BACKGROUND

Tight junctions (TJs) organise paracellular permeability and they have an important role in epithelial and endothelial cell polarity and permanence of barrier function. It has been demonstrated that the Claudin family constitutes an important component of them. In this study, we assessed expression patterns of of Claudin1, 4 and 7 and whether they have any relation with prognosis in patients with pancreatic cancer.

MATERIALS AND METHODS

Expression patterns of Claudin 1,4 and 7 were examined by immunohistochemistry in 25 patients with a histopathological diagnosis of pancreatic cancer using a semiquantitative scoring of the extent and intensity of staining. After grouping the staining scores as low (final score 0-2) and high (final score 3-9) the relation between expression of Claudin 1,4 and 7 and survival was evaluated.

RESULTS

There was no significant relation between expression of Claudin 1,4 and 7 and gender and stage. No statistically significant relation was found between Claudin 1 and 4 expression and survival whereas a statistically significant relation was found between decrease in Claudin 7 expression and decrease in survival.

CONCLUSIONS

Claudins have important functions other than their popular function known as adhesion. Supporting this hypothesis, we found a statistically significant relationship between increased Claudin 7 expression and increased survival time, and this suggests that Claudin 7 may exert different tumorigenic effects in pancreatic cancer other than its well- known adhesion effect.

Claudin-4 binder C-CPE 194 enhances effects of anticancer agents on pancreatic cancer cell lines via a MAPK pathway

The C‐terminal fragment of Clostridium perfringens enterotoxin (C‐CPE) modulates the tight junction protein claudin and disrupts the tight junctional barrier. It also can enhance the effectiveness of anticancer agents. However, the detailed mechanisms of the effects of C‐CPE remain unclear in both normal and cancerous cells. The C‐CPE mutant called C‐CPE 194 binds only to claudin‐4, but the C‐CPE 194 mutant called C‐CPE m19 binds not only to claudin‐4 but also to claudin‐1. In the present study, to investigate the mechanisms of the effects of C‐CPE on claudin expression, the tight junctional functions and the cytotoxicity of anticancer agents, human pancreatic cancer cells, and normal human pancreatic duct epithelial cells (HPDEs) were treated with C‐CPE 194 and C‐CPE m19. In well‐differentiated cells of the pancreatic cancer cell line HPAC, C‐CPE 194 and C‐CPE m19 disrupted both the barrier and fence functions without changes in expression of claudin‐1 and ‐4, together with an increase of MAPK phosphorylation. C‐CPE 194, but not C‐CPE m19, enhanced the cytotoxicity of the anticancer agents gemcitabine and S‐1. In poorly differentiated pancreatic cancer cell line PANC‐1, C‐CPE 194, but not C‐CPE m19, decreased claudin‐4 expression and enhanced MAPK activity and the cytotoxicity of the anticancer agents. In normal HPDEs, C‐CPE 194 and C‐CPE m19 decreased claudin‐4 expression and enhanced the MAPK activity, whereas they did not affect the cytotoxicity of the anticancer agents. Our findings suggest that the claudin‐4 binder C‐CPE 194 enhances effects of anticancer agents on pancreatic cancer cell lines via a MAPK pathway.

Down regulated expression of Claudin-1 and Claudin-5 and up regulation of β-catenin: association with human glioma progression

Glioblastoma multiforme is the most common form of intracranial malignancy in humans, and is characterized by aggressive tumor growth, tissue invasion and neurodegenerative properties. The present study investigated the expression status of tight junction associated Claudin 1 (CLDN1), Claudin 5 (CLDN5) and Adheren junction associated β-catenin genes in the light of their critical role in the progression of both low- and high-grade human gliomas. Using quantitative PCR and Western blot methods the mRNA and protein status of CLDN1, CLDN5 and β-catenin genes were studied in a total of 25 human gliomas of World Health Organization (WHO) grades I-IV, non-cancerous control brain tissues and their corresponding model cell lines (C6, U373, U118, T98 and U87MG). Quantitative analysis of the transcript and protein expression data showed that CLDN1 and CLDN5 were significantly down regulated (p=<0.001) in tumors of all four grades and model cell lines. This decrease in expression pattern was in accordance with the increasing grade of the tumor. A 4-fold stronger reduction of CLDN1 when compared to CLDN5 was evident in high-grade tumors. Interestingly, β-catenin was up regulated in all tumor types we studied (p=<0.005). Our findings, suggest that down regulated CLDN1 and CLDN5 genes have potential relevance in relation to the progression of glioblastoma multiforme. Hence, their therapeutic targeting may provide both insight and leads to control the cellular proliferation and subsequent invasiveness among affected individuals.

Determination of the protein expression profiles of breast cancer cell lines by quantitative proteomics using iTRAQ labelling and tandem mass spectrometry

Breast cancer is the principal cancer in women worldwide. Although there are serum tumor markers such as CEA and HER2, they are detected in advanced stages of the disease and used as progression and recurrence markers. Therefore, there is a necessity for the identification of new markers that might lead to an early detection and also provide evidence of an effective treatment. The aim of this work was to determine the differential protein expression profiles of four breast cancer cell lines in comparison to a normal control cell line by iTRAQ labelling and tandem mass spectrometry, in order to identify putative biomarkers of the disease. We identified 1,020 iTRAQ-labelled polypeptides with at least one peptide identified with more than 95% in confidence. Overexpressed polypeptides in all cancer cell lines were 78, whilst the subexpressed were 128. We categorised them with PANTHER program into biological processes, being the metabolic pathways the most affected. We detected six groups of proteins with the STRING program involved in DNA topology, glycolysis, translation initiation, splicing, pentose pathway, and proteasome degradation. The main subexpressed protein network included mitochondrial proteins involved in oxidative phosphorylation. We propose BAG6, DDX39, ANXA8 and COX4 as putative biomarkers in breast cancer.

BIOLOGICAL SIGNIFICANCE

We report a set of differentially expressed proteins in the MCF7 and T47D (Luminal A), MDA-MB-231 (Claudin low) and SK-BR-3 (HER2(+)) breast cancer cell lines that have not been previously reported in breast cancer disease. From these proteins, we propose BAG6, DDX39, ANXA8 and COX4 as putative biomarkers in breast cancer. On the other hand, we propose sets of unique polypeptides in each breast cancer cell line that can be useful in the classification of different subtypes of breast cancer.

Annexin A8 identifies a subpopulation of transiently quiescent c-kit positive luminal progenitor cells of the ductal mammary epithelium

We have previously shown that Annexin A8 (ANXA8) is strongly associated with the basal-like subgroup of breast cancers, including BRCA1-associated breast cancers, and poor prognosis; while in the mouse mammary gland AnxA8 mRNA is expressed in low-proliferative isolated pubertal mouse mammary ductal epithelium and after enforced involution, but not in isolated highly proliferative terminal end buds (TEB) or during pregnancy. To better understand ANXA8's association with this breast cancer subgroup we established ANXA8's cellular distribution in the mammary gland and ANXA8's effect on cell proliferation. We show that ANXA8 expression in the mouse mammary gland was strong during pre-puberty before the expansion of the rudimentary ductal network and was limited to a distinct subpopulation of ductal luminal epithelial cells but was not detected in TEB or in alveoli during pregnancy. Similarly, during late involution its expression was found in the surviving ductal epithelium, but not in the apoptotic alveoli. Double-immunofluorescence (IF) showed that ANXA8 positive (+ve) cells were ER-alpha negative (-ve) and mostly quiescent, as defined by lack of Ki67 expression during puberty and mid-pregnancy, but not terminally differentiated with ∼15% of ANXA8 +ve cells re-entering the cell cycle at the start of pregnancy (day 4.5). RT-PCR on RNA from FACS-sorted cells and double-IF showed that ANXA8+ve cells were a subpopulation of c-kit +ve luminal progenitor cells, which have recently been identified as the cells of origin of basal-like breast cancers. Over expression of ANXA8 in the mammary epithelial cell line Kim-2 led to a G0/G1 arrest and suppressed Ki67 expression, indicating cell cycle exit. Our data therefore identify ANXA8 as a potential mediator of quiescence in the normal mouse mammary ductal epithelium, while its expression in basal-like breast cancers may be linked to ANXA8's association with their specific cells of origin.

Utility of immunohistochemistry in the pancreatobiliary tract

CONTEXT

Immunohistochemistry has become a useful ancillary study in the identification and classification of pancreatic neoplasms. The diagnostic accuracy has been significantly improved because of the continuous discoveries of tumor-associated biomarkers and the development of effective immunohistochemical panels.

OBJECTIVES

To identify and classify pancreatic neoplasms by immunohistochemistry.

DATA SOURCES

Literature review and authors' research data and personal practice experience were used.

CONCLUSIONS

To better guide therapeutic decisions and predict the prognostic outcome, it is crucial to make an accurate diagnosis of a pancreatic neoplasm. Application of appropriate immunohistochemical panels enables pathologists to differentiate pancreaticobiliary adenocarcinomas from reactive conditions and to identify rare types of pancreatic neoplasms. Knowing the utilities and pitfalls of each tumor-associated biomarker is essential to avoiding a potential diagnostic error because an absolutely cancer-specific biomarker does not exist. This article reviews frequently used tumor-associated biomarkers, provides lists of effective immunohistochemical panels, and recommends a diagnostic algorithm as a standard approach to pancreatic neoplasms.

Annexin A8 Is a Prognostic Marker and Potential Therapeutic Target for Pancreatic Cancer

OBJECTIVES

We investigated whether annexin A8 (A-A8), a Ca-binding protein overexpressed in pancreatic cancer, plays a role in cell growth and migration and investigated its association with pancreatic cancer prognosis.

METHODS

Clinicopathological features and associations between increased A-A8 expression (determined by immunohistochemistry) and histologic grade were studied in a tissue microarray of 90 patients with resected stage I/II pancreatic cancer. We investigated A-A8's effect on cell migration, proliferation, and colony formation in 2 pancreatic cancer cells (BXPC-3 and Panc-1). Statistical analyses included Fisher exact test, t test, analysis of variance, and survival analysis.

RESULTS

Western blot showed increased A-A8 expression in human pancreatic cancer cells, with A-A8 knockdown in BXPC-3 and Panc-1 cells demonstrating decreased cell viability (P = 0.017 and P = 0.001), migration (2.5 vs 0.9 mm and 1.6 vs 1 mm at 96 hours; P = 0.048 and P = 0.004), and colony formation (approximately 75% and 40% from scramble; P ≤ 0.01), respectively. In our tissue microarray, A-A8 expression increased 5.9-fold (r = 0.31; P = 0.019) from low- to high-grade tumors, correlating with tumor grade (r = 0.23; P = 0.027). In addition, high A-A8 expression was associated with a decreased 5-year survival (P = 0.042).

CONCLUSIONS

Our study is the first showing that increased A-A8 expression is associated with poor prognosis in early-stage pancreatic cancer, thus supporting its further investigation as a future therapeutic target and prognostic marker.

Transcriptional profiling of peripheral blood in pancreatic adenocarcinoma patients identifies diagnostic biomarkers

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy associated with poor survival rates. Fast detection of PDAC appears to be the most relevant strategy to improve the long-term survival of patients.

AIMS

Our objective was to identify new markers in peripheral blood that differentiates between PDAC patients and healthy controls.

METHODS

Peripheral blood samples from PDAC patients (n = 18) and controls (n = 18) were analyzed by whole genome cDNA microarray hybridization. The most relevant genes were validated by quantitative real-time PCR (RT-qPCR) in the same set of samples. Finally, our gene prediction set was tested in a blinded set of new peripheral blood samples (n = 30).

RESULTS

Microarray studies identified 87 genes differentially expressed in peripheral blood samples from PDAC patients. Four of these genes were selected for analysis by RT-qPCR, which confirmed the previously observed changes. In our blinded validation study, the combination of CLEC4D and IRAK3 predicted the diagnosis of PDAC with 93 % accuracy, with a sensitivity of 86 % and specificity of 100 %.

CONCLUSIONS

Peripheral blood gene expression profiling is an useful tool for the diagnosis of PDAC. We present a validated four-gene predictor set (ANKRD22, CLEC4D, VNN1, and IRAK3) that may be useful in PDAC diagnosis.

Role of tight junctions in signal transduction: an update

Tight junctions (TJs), which are the most apically located of the intercellular junctional complexes, have a barrier function and a fence function. Recent studies show that they also participate in signal transduction mechanisms. TJs are modulated by intracellular signaling pathways including protein kinase C, mitogen-activated protein kinase, and NF-ϰB, to affect the epithelial barrier function in response to diverse stimuli. TJs are also regulated by various cytokines, growth factors, and hormones via signaling pathways. To investigate the regulation of TJ molecules via signaling pathways in human epithelial cells under normal and pathological conditions, we established a novel model of human telomerase reverse transcriptase-transfected human epithelial cells. In this review, we describe the recent progress in our understanding of the role of TJs for signal transduction under normal conditions in upper airway epithelium, pancreatic duct epithelial cells, hepatocytes, and endometrial epithelial cells, and in pathological conditions including cancer and infection.

Targeting tight junctions during epithelial to mesenchymal transition in human pancreatic cancer

Pancreatic cancer continues to be a leading cause of cancer-related death worldwide and there is an urgent need to develop novel diagnostic and therapeutic strategies to reduce the mortality of patients with this disease. In pancreatic cancer, some tight junction proteins, including claudins, are abnormally regulated and therefore are promising molecular targets for diagnosis, prognosis and therapy. Claudin-4 and -18 are overexpressed in human pancreatic cancer and its precursor lesions. Claudin-4 is a high affinity receptor of Clostridium perfringens enterotoxin (CPE). The cytotoxic effects of CPE and monoclonal antibodies against claudin-4 are useful as novel therapeutic tools for pancreatic cancer. Claudin-18 could be a putative marker and therapeutic target with prognostic implications for patients with pancreatic cancer. Claudin-1, -7, tricellulin and marvelD3 are involved in epithelial to mesenchymal transition (EMT) of pancreatic cancer cells and thus might be useful as biomarkers during disease. Protein kinase C is closely related to EMT of pancreatic cancer and regulates tight junctions of normal human pancreatic duct epithelial cells and the cancer cells. This review focuses on the regulation of tight junctions via protein kinase C during EMT in human pancreatic cancer for the purpose of developing new diagnostic and therapeutic modalities for pancreatic cancer.

Aberrantly activated claudin 6 and 18.2 as potential therapy targets in non-small-cell lung cancer

Claudins (CLDNs) are central components of tight junctions that regulate epithelial-cell barrier function and polarity. Altered CLDN expression patterns have been demonstrated in numerous cancer types and lineage-specific CLDNs have been proposed as therapy targets. The objective of this study was to assess which fraction of patients with non-small-cell lung cancer (NSCLC) express CLDN6 and CLDN18 isoform 2 (CLDN18.2). Protein expression of CLDN6 and CLDN18.2 was examined by immunohistochemistry on a tissue microarray (n = 355) and transcript levels were supportively determined based on gene expression microarray data from fresh-frozen NSCLC tissues (n = 196). Both were analyzed with regard to frequency, distribution and association with clinical parameters. Immunohistochemical analysis of tissue sections revealed distinct membranous positivity of CLDN6 (6.5%) and CLDN18.2 (3.7%) proteins in virtually non-overlapping subgroups of adenocarcinomas and large-cell carcinomas. Pneumocytes and bronchial epithelial cells were consistently negative. Corresponding to the protein expression, in subsets of non-squamous lung carcinoma high mRNA levels of CLDN6 (7-16%) and total CLDN18 (5-12%) were observed. Protein expression correlated well with total mRNA expression of the corresponding gene (rho = 0.4-0.8). CLDN18.2 positive tumors were enriched among slowly proliferating, thyroid transcription factor 1 (TTF-1)-negative adenocarcinomas, suggesting that isoform-specific CLDN expression may delineate a specific subtype. Noteworthy, high CLDN6 protein expression was associated with worse prognosis in lung adenocarcinoma in the univariate [hazard ratio (HR): 1.8; p = 0.03] and multivariate COX regression model (HR: 1.9; p = 0.02). These findings encourage further clinical exploration of targeting ectopically activated CLDN expression as a valuable treatment concept in NSCLC.