Involvement of annexin A8 in the properties of pancreatic cancer

Promoter Hypomethylation Upregulates ANXA2 Expression in Pancreatic Cancer and is Associated with Poor Prognosis

Pancreatic cancer (PC) is one of the world's most aggressive and deadly cancers, owing to non-specific early clinical symptoms, late-stage diagnosis, and poor survival. Therefore, it is critical to identify specific biomarkers for its early diagnosis. Annexin A2 (ANXA2) is a calcium-dependent phospholipid-binding protein that has been reported to be upregulated in several cancer types, making it an emerging biomarker and potential cancer therapeutic target. However, the mechanism underlying the regulation of ANXA2 overexpression is still unclear. It is well established that genetic and epigenetic alterations may lead to widespread dysregulation of gene expression. Hence, in this study, we focused on exploring the regulatory mechanism of ANXA2 by investigating the transcriptional profile, methylation pattern, somatic mutation, and prognostic value of ANXA2 in PC using several bioinformatics databases. Our results revealed that the expression levels of ANXA2 were remarkably increased in PC tissues comparing to normal tissues. Furthermore, the high expression of ANXA2 was significantly related to the poor prognosis of PC patients. More importantly, we demonstrated for the first time that the ANXA2 promoter is hypomethylated in PC tissues compared to normal tissues which may result in ANXA2 overexpression in PC. However, more experimental research is required to corroborate our findings.

Analysis of a large cohort of pancreatic cancer transcriptomic profiles to reveal the strongest prognostic factors

Pancreatic adenocarcinoma remains a leading cause of cancer-related deaths. In order to develop appropriate therapeutic and prognostic tools, a comprehensive mapping of the tumor's molecular abnormalities is essential. Here, our aim was to integrate available transcriptomic data to uncover genes whose elevated expression is simultaneously linked to cancer pathogenesis and inferior survival. A comprehensive search was performed in GEO to identify clinical studies with transcriptome-level gene expression data of pancreatic carcinoma with overall survival data and normal pancreatic tissues. After quantile normalization, the entire database was used to identify genes with altered expression. Cox proportional hazard regression was employed to uncover genes most strongly correlated with survival with a Bonferroni corrected p < 0.01. Perturbed biological processes and molecular pathways were identified to enable the understanding of underlying processes. A total of 16 available datasets were combined. The aggregated database comprised data of 1640 samples for 20,443 genes. When comparing with normal pancreatic tissues, a total of 2612 upregulated and 1977 downregulated genes were uncovered in pancreatic carcinoma. Among these, we found 24 genes with higher expression which significantly correlated with overall survival length also. The most significant genes were ANXA8, FAM83A, KRT6A, MET, MUC16, NT5E, and SLC2A1. These genes remained significant after a multivariate analysis also including grade and stage. Here, we assembled a large-scale database of pancreatic carcinoma samples and used this cohort to identify carcinoma-specific genes linked to altered survival outcomes. As our analysis focused on genes with higher expression, these could serve as future therapy targets.

Evaluation of Annexins Family as Potential Biomarker for Predicting Progression and Prognosis in Clear Renal Cell Carcinoma

Background. Annexins family (ANXAs), as a Ca2+-dependent phospholipid-binding protein superfamily, participates in a wide variety of biological activities and has been reported to be dysregulated in numerous types of human cancers. Evidence from cell lines and human tissues indicates that ANAXs are involved in kidney clear renal cell carcinoma (KIRC) tumorigenesis. However, their prognostic value and expression pattern associated with KIRC remain to be elucidated. Methods. We visited public databases, including ONCOMINE, Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan–Meier plotter, cBioPortal, and GeneMANIA, to conduct comprehensive bioinformatics analysis and tried to detect basic relationships between each Annexins family member and KIRC. Results. We found that the expression level of ANXA1/2/4/5/6/7/8/13 in clear renal cell carcinoma tissue was higher than that in the kidney tissue, while the expression level of ANXA3/9/11 in the former was lower than that in the latter. The expression level of ANXA7/8/13 is related to the stage of the tumour. Survival analysis using the Kaplan–Meier plotter database showed that a high transcription level of ANXA2/5/8/10 is related to a low overall survival rate (OS) in predicting KIRC patients. In contrast, high ANXA3/4/7/9/11/13 levels are associated with a high OS in these patients. Conclusions. Our study implies that ANXA4/8/13 are potential targets of precision therapy for patients with KIRC and that ANXA2/5/8/10 are new biomarkers for the prognosis of KIRC.

Copy number amplification and SP1-activated lncRNA MELTF-AS1 regulates tumorigenesis by driving phase separation of YBX1 to activate ANXA8 in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) are reported to play key roles in tumorigenesis. However, the mechanisms underlying lncRNA-mediated regulation of RNA-binding protein phase separation in tumorigenesis have not been completely elucidated. In this study, an oncogenic lncRNA MELTF-AS1 was identified using systematic data analysis, screening, and verification. MELTF-AS1 was markedly upregulated in non-small cell lung cancer (NSCLC). High MELTF-AS1 levels were associated with advanced tumor-node-metastasis stage (TNM), high tumor size, and decreased survival time. Functionally, MELTF-AS1 regulated cell proliferation and metastasis in vitro and in vivo. RNA sequencing analysis revealed that MELTF-AS1 knockdown specifically modulated genes associated with cell proliferation, apoptosis, and migration. Mechanistically, at the genome level, copy number amplification promoted MELTF-AS1 expression. At the transcriptional level, the transcription factor SP1 directly activated MELTF-AS1 transcription by binding to its promoter. Furthermore, MELTF-AS1 could directly bind and drive the phase separation of YBX1, which was an RNA-binding protein and involved in tumorigenesis, thus activating ANXA8 transcription and promoting tumorigenesis of NSCLC. Aberrant activation of ANXA8 and promotion of tumorigenesis have been found in a variety of tumors. These novel findings demonstrated the critical role of MELTF-AS1-driven phase separation-mediated transcriptional regulation and provided a potential novel diagnostic and therapeutic target for NSCLC.

Renal Ischemia Induces Epigenetic Changes in Apoptotic, Proteolytic, and Mitochondrial Genes in Swine Scattered Tubular-like Cells

BACKGROUND

Scattered tubular-like cells (STCs) are dedifferentiated renal tubular cells endowed with progenitor-like characteristics to repair injured parenchymal cells. STCs may be damaged and rendered ineffective by renal artery stenosis (RAS), but the underlying processes remain unclear. We hypothesized that RAS alters the epigenetic landscape on DNA and the ensuing gene transcriptional profile of swine STCs.

METHODS

CD24+/CD133+ STCs were isolated from pig kidneys after 10 weeks of RAS or sham (n = 3 each) and their whole 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) profiles were examined by 5mC and 5hmC immunoprecipitation sequencing (MeDIP-/hMeDIP-seq, respectively). A subsequent integrated (MeDIP/hMeDIP-seq/mRNA-seq) analysis was performed by comparing all online available gene sets using Gene Set Enrichment Analysis. Apoptosis, proteolysis, and mitochondrial structure and function were subsequently evaluated in vitro.

RESULTS

Differential expression (DE) analysis revealed 239 genes with higher and 236 with lower 5mC levels and 275 genes with higher and 315 with lower 5hmC levels in RAS-STCs compared to Normal-STCs (fold change ≥1.4 or ≤0.7, p ≤ 0.05). Integrated MeDIP-/hMeDIP-seq/mRNA-seq analysis identified several overlapping (DE-5mC/mRNA and DE-5hmC/mRNA levels) genes primarily implicated in apoptosis, proteolysis, and mitochondrial functions. Furthermore, RAS-STCs exhibited decreased apoptosis, mitochondrial matrix density, and ATP production, and increased intracellular amino acid concentration and ubiquitin expression.

CONCLUSIONS

Renal ischemia induces epigenetic changes in apoptosis-, proteolysis-, and mitochondria-related genes, which correlate with alterations in the transcriptomic profile and corresponding function of swine STCs. These observations may contribute to developing novel targeted interventions to preserve the reparative potency of STCs in renal disease.

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.

Microdissected pancreatic cancer proteomes reveal tumor heterogeneity and therapeutic targets

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a relative paucity of cancer cells that are surrounded by an abundance of nontumor cells and extracellular matrix, known as stroma. The interaction between stroma and cancer cells contributes to poor outcome, but how proteins from these individual compartments drive aggressive tumor behavior is not known. Here, we report the proteomic analysis of laser-capture microdissected (LCM) PDAC samples. We isolated stroma, tumor, and bulk samples from a cohort with long- and short-term survivors. Compartment-specific proteins were measured by mass spectrometry, yielding what we believe to be the largest PDAC proteome landscape to date. These analyses revealed that, in bulk analysis, tumor-derived proteins were typically masked and that LCM was required to reveal biology and prognostic markers. We validated tumor CALB2 and stromal COL11A1 expression as compartment-specific prognostic markers. We identified and functionally addressed the contributions of the tumor cell receptor EPHA2 to tumor cell viability and motility, underscoring the value of compartment-specific protein analysis in PDAC.

Annexin A8 regulates Wnt signaling to maintain the phenotypic plasticity of retinal pigment epithelial cells

Wnt signalling mediates complex cell-cellinteractions during development and proliferation. Annexin A8 (AnxA8), a calcium-dependent phospholipid-binding protein, and canonical Wnt signalling mechanisms have both been implicated in retinal pigment epithelial (RPE) cell differentiation. The aim here was to examine the possibility of cross-talk between AnxA8 and Wnt signalling, as both are down-regulated upon fenretinide (FR)-mediated RPE transdifferentiation. AnxA8 suppression in RPE cells via siRNA or administration of FR induced neuronal-like cell transdifferentiation and reduced expression of Wnt-related genes, as measured by real-time PCR and western blotting. AnxA8 gene expression, on the other hand, remained unaltered upon manipulating Wnt signalling, suggesting Wnt-related genes to be downstream effectors of AnxA8. Co-immunoprecipitation revealed an interaction between AnxA8 and β-catenin, which was reduced in the presence of activated TGF-β1. TGF-β1 signalling also reversed the AnxA8 loss-induced cell morphology changes, and induced β-catenin translocation and GSK-3β phosphorylation in the absence of AnxA8. Ectopic over-expression of AnxA8 led to an increase in active β-catenin and GSK-3β phosphorylation. These data demonstrate an important role for AnxA8 as a regulator of Wnt signalling and a determinant of RPE phenotype, with implications for regenerative medicine approaches that utilise stem cell-derived RPE cells to treat conditions such as age-related macular degeneration.

Annexin A8 can serve as potential prognostic biomarker and therapeutic target for ovarian cancer: based on the comprehensive analysis of Annexins

BACKGROUND

Annexins are involved in vesicle trafficking, cell proliferation and apoptosis, but their functional mechanisms in ovarian cancer remain unclear. In this study, we analyzed Annexins in ovarian cancer using different databases and selected Annexin A8 (ANXA8), which showed the greatest prognostic value, for subsequent validation in immunohistochemical (IHC) assays.

METHODS

The mRNA expression levels, genetic variations, prognostic values and gene-gene interaction network of Annexins in ovarian cancer were analyzed using the Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), cBioPortal, Kaplan-Meier plotter and GeneMANIA database. ANXA8 was selected for analyzing the biological functions and pathways of its co-expressed genes, and its correlation with immune system responses via the Database for Annotation, Visualization, and Integrated Discovery (DAVID) and the TISIDB database, respectively. We validated the expression of ANXA8 in ovarian cancer via IHC assays and analyzed its correlation with clinicopathological parameters and prognosis.

RESULTS

ANXA2/3/8/11 mRNA expression levels were significantly upregulated in ovarian cancer, and ANXA5/6/7 mRNA expression levels were significantly downregulated. Prognostic analysis suggested that significant correlations occurred between ANXA2/4/8/9 mRNA upregulation and poor overall survival, and between ANXA8/9/11 mRNA upregulation and poor progression-free survival in patients with ovarian serous tumors. Taken together, results suggested that ANXA8 was most closely associated with ovarian cancer tumorigenesis and progression. Further analyses indicated that ANXA8 may be involved in cell migration, cell adhesion, and vasculature development, as well as in the regulation of PI3K-Akt, focal adhesion, and proteoglycans. Additionally, ANXA8 expression was significantly correlated with lymphocytes and immunomodulators. The IHC results showed that ANXA8 expression was higher in the malignant tumor group than in the borderline and benign tumor groups and normal ovary group, and high ANXA8 expression was an independent risk factor for survival and prognosis of ovarian cancer patients (P = 0.013).

CONCLUSIONS

Members of the Annexin family display varying degrees of abnormal expressions in ovarian cancer. ANXA8 was significantly highly expressed in ovarian cancer, and high ANXA8 expression was significantly correlated with poor prognosis. Therefore, ANXA8 is a high candidate as a novel biomarker and therapeutic target for ovarian cancer.

Distinct signatures of lung cancer types: aberrant mucin O-glycosylation and compromised immune response

BACKGROUND

Genomic initiatives such as The Cancer Genome Atlas (TCGA) contain data from -omics profiling of thousands of tumor samples, which may be used to decipher cancer signaling, and related alterations. Managing and analyzing data from large-scale projects, such as TCGA, is a demanding task. It is difficult to dissect the high complexity hidden in genomic data and to account for inter-tumor heterogeneity adequately.

METHODS

In this study, we used a robust statistical framework along with the integration of diverse bioinformatic tools to analyze next-generation sequencing data from more than 1000 patients from two different lung cancer subtypes, i.e., the lung adenocarcinoma (LUAD) and the squamous cell carcinoma (LUSC).

RESULTS

We used the gene expression data to identify co-expression modules and differentially expressed genes to discriminate between LUAD and LUSC. We identified a group of genes which could act as specific oncogenes or tumor suppressor genes in one of the two lung cancer types, along with two dual role genes. Our results have been validated against other transcriptomics data of lung cancer patients.

CONCLUSIONS

Our integrative approach allowed us to identify two key features: a substantial up-regulation of genes involved in O-glycosylation of mucins in LUAD, and a compromised immune response in LUSC. The immune-profile associated with LUSC might be linked to the activation of three oncogenic pathways, which promote the evasion of the antitumor immune response. Collectively, our results provide new future directions for the design of target therapies in lung cancer.

Annexins in Adipose Tissue: Novel Players in Obesity

Obesity and the associated comorbidities are a growing health threat worldwide. Adipose tissue dysfunction, impaired adipokine activity, and inflammation are central to metabolic diseases related to obesity. In particular, the excess storage of lipids in adipose tissues disturbs cellular homeostasis. Amongst others, organelle function and cell signaling, often related to the altered composition of specialized membrane microdomains (lipid rafts), are affected. Within this context, the conserved family of annexins are well known to associate with membranes in a calcium (Ca²⁺)- and phospholipid-dependent manner in order to regulate membrane-related events, such as trafficking in endo- and exocytosis and membrane microdomain organization. These multiple activities of annexins are facilitated through their diverse interactions with a plethora of lipids and proteins, often in different cellular locations and with consequences for the activity of receptors, transporters, metabolic enzymes, and signaling complexes. While increasing evidence points at the function of annexins in lipid homeostasis and cell metabolism in various cells and organs, their role in adipose tissue, obesity and related metabolic diseases is still not well understood. Annexin A1 (AnxA1) is a potent pro-resolving mediator affecting the regulation of body weight and metabolic health. Relevant for glucose metabolism and fatty acid uptake in adipose tissue, several studies suggest AnxA2 to contribute to coordinate glucose transporter type 4 (GLUT4) translocation and to associate with the fatty acid transporter CD36. On the other hand, AnxA6 has been linked to the control of adipocyte lipolysis and adiponectin release. In addition, several other annexins are expressed in fat tissues, yet their roles in adipocytes are less well examined. The current review article summarizes studies on the expression of annexins in adipocytes and in obesity. Research efforts investigating the potential role of annexins in fat tissue relevant to health and metabolic disease are discussed.

Distinct prognostic values of Annexin family members expression in acute myeloid leukemia

BACKGROUND

Annexin family consist of 12 members, many of them are frequently dysregulated in human cancers. However, the diagnosis and prognosis of Annexin family expression in acute myeloid leukemia (AML) remain elusive. The aim of the present study was to assess the prognostic value of Annexin expressions in adult and pediatric AML.

METHODS

GenomicScape tool was used to assess the prognostic value of the expressions of Annexin family members in a cohort of 162 adult AML patients. Quantitative reverse transcript real-time PCR (QRT-PCR) was performed to detect the ANXA2 expression level in the bone marrow-derived mononuclear cells (BMMCs) obtained from 101 pediatric AML patients and 30 controls.

RESULTS

The results demonstrated that high mRNA expressions of ANXA2, ANXA6, and ANXA7 were significantly associated with worse prognosis, while ANXA5 was correlated with better prognosis in adult AML. QRT-PCR analysis showed that ANXA2 expression was dramatically downregulated in BMMCs of pediatric AML patients compared to controls (p < 0.0001). ROC analysis demonstrated that ANXA2 could efficiently differentiate pediatric AML patients from controls (AUC 0.872, p < 0.0001). Likewise, ANXA2 was significantly lower in AML patients with poor-risk karyotype (p = 0.048). Also, the level of ANXA2 trended to decrease in AML patients who had not achieving complete remission. Moreover, patients with lower expression of ANXA2 had higher death rate (p = 0.042) and shorter overall survival (HR 0.55, p = 0.042). Thus, these findings suggest that ANXA2 exerts poor prognostic effect on adult AML but favorable prognostic effect on pediatric AML.

CONCLUSIONS

Collectively, Annexin family members exert distinct prognostic roles in AML, and ANXA2 can be used as a biological marker for diagnosis and prognosis of pediatric AML.

Detection of annexin A8 antibodies in serum of patients with antiphospholipid syndrome

Introduction

Antibodies specific for annexin A8 (AnxA8) have not been investigated in patients suffering from antiphospholipid syndrome (APS) yet. The aim of this study was to compare the presence of AnxA8 antibodies in serum of APS patients with that of age-matched healthy controls and to investigate whether AnxA8 antibodies are potential biomarkers for APS.

Materials and methods

We enrolled 22 APS patients and 22 healthy controls in this case-control study. We used sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblot to investigate the presence of AnxA8 antibodies, and we applied enzyme-linked immunosorbent assay to investigate the presence of cardiolipin (CL) and beta-2-glycoprotein I (ß2GPI) antibodies.

Results

The serum of 9/22 APS patients showed AnxA8 IgG isotype antibody reactivity compared to serum of 2/22 healthy controls (P = 0.034). When we also included weak immunoblot signals, 12/22 APS patients exhibited AnxA8 IgG isotype antibody reactivity compared to 3/22 healthy controls (P = 0.005). We also investigated the presence of AnxA8 IgM isotype antibodies in the serum of APS patients but found no statistically significant difference between the APS patient group and healthy control group (P = 0.500). We further investigated the presence of ß2GPI and CL IgG and IgM isotype antibodies. AnxA8 IgG isotype antibodies were present in APS patients in a similar frequency as the APS “criteria” antibody against CL (P = 0.764).

Conclusion

We demonstrated that AnxA8 IgG isotype antibodies are potential biomarkers for the diagnosis of APS.

Regulation of retinal pigment epithelial cell phenotype by Annexin A8

The retinoic acid derivative fenretinide (FR) is capable of transdifferentiating cultured retinal pigment epithelial (RPE) cells towards a neuronal-like phenotype, but the underlying mechanisms are not understood. To identify genes involved in this process we performed a microarray analysis of RPE cells pre- and post-FR treatment, and observed a marked down-regulation of AnnexinA8 (AnxA8) in transdifferentiated cells. To determine whether AnxA8 plays a role in maintaining RPE cell phenotype we directly manipulated AnxA8 expression in cultured and primary RPE cells using siRNA-mediated gene suppression, and over-expression of AnxA8-GFP in conjunction with exposure to FR. Treatment of RPE cells with AnxA8 siRNA recapitulated exposure to FR, with cell cycle arrest, neuronal transdifferentiation, and concomitant up-regulation of the neuronal markers calretinin and calbindin, as assessed by real-time PCR and immunofluorescence. In contrast, AnxA8 transient over-expression in ARPE-19 cells prevented FR-induced differentiation. Ectopic expression of AnxA8 in AnxA8-depleted cells led to decreased neuronal marker staining, and normal cell growth as judged by phosphohistone H3 staining, cell counting and cleaved caspase-3 levels. These data show that down-regulation of AnxA8 is both necessary and sufficient for neuronal transdifferentiation of RPE cells and reveal an essential role for AnxA8 as a key regulator of RPE phenotype.

Integrated molecular analysis reveals complex interactions between genomic and epigenomic alterations in esophageal adenocarcinomas

The incidence of esophageal adenocarcinoma (EAC) is rapidly rising in the United States and Western countries. In this study, we carried out an integrative molecular analysis to identify interactions between genomic and epigenomic alterations in regulating gene expression networks in EAC. We detected significant alterations in DNA copy numbers (CN), gene expression levels, and DNA methylation profiles. The integrative analysis demonstrated that altered expression of 1,755 genes was associated with changes in CN or methylation. We found that expression alterations in 84 genes were associated with changes in both CN and methylation. These data suggest a strong interaction between genetic and epigenetic events to modulate gene expression in EAC. Of note, bioinformatics analysis detected a prominent K-RAS signature and predicted activation of several important transcription factor networks, including β-catenin, MYB, TWIST1, SOX7, GATA3 and GATA6. Notably, we detected hypomethylation and overexpression of several pro-inflammatory genes such as COX2, IL8 and IL23R, suggesting an important role of epigenetic regulation of these genes in the inflammatory cascade associated with EAC. In summary, this integrative analysis demonstrates a complex interaction between genetic and epigenetic mechanisms providing several novel insights for our understanding of molecular events in EAC.

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.

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 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.

Characterization of the altered gene expression profile in early porcine embryos generated from parthenogenesis and somatic cell chromatin transfer

The in vitro production of early porcine embryos is of particular scientific and economic interest. In general, embryos produced from in vitro Assisted Reproductive Technologies (ART) manipulations, such as somatic cell chromatin transfer (CT) and parthenogenetic activation (PA), are less developmentally competent than in vivo–derived embryos. The mechanisms underlying the deficiencies of embryos generated from PA and CT have not been completely understood. To characterize the altered genes and gene networks in embryos generated from CT and PA, comparative transcriptomic analyses of in vivo (IVV) expanded blastocysts (XB), IVV hatched blastocyst (HB), PA XB, PA HB, and CT HB were performed using a custom microarray platform enriched for genes expressed during early embryonic development. Differential expressions of 1492 and 103 genes were identified in PA and CT HB, respectively, in comparison with IVV HB. The “eIF2 signalling”, “mitochondrial dysfunction”, “regulation of eIF4 and p70S6K signalling”, “protein ubiquitination”, and “mTOR signalling” pathways were down-regulated in PA HB. Dysregulation of notch signalling–associated genes were observed in both PA and CT HB. TP53 was predicted to be activated in both PA and CT HB, as 136 and 23 regulation targets of TP53 showed significant differential expression in PA and CT HB, respectively, in comparison with IVV HB. In addition, dysregulations of several critical pluripotency, trophoblast development, and implantation-associated genes (NANOG, GATA2, KRT8, LGMN, and DPP4) were observed in PA HB during the blastocyst hatching process. The critical genes that were observed to be dysregulated in CT and PA embryos could be indicative of underlying developmental deficiencies of embryos produced from these technologies.