Gene Summary

Gene:AGR2; anterior gradient 2, protein disulphide isomerase family member
Aliases: AG2, AG-2, HPC8, GOB-4, HAG-2, XAG-2, PDIA17, HEL-S-116
Summary:This gene encodes a member of the disulfide isomerase (PDI) family of endoplasmic reticulum (ER) proteins that catalyze protein folding and thiol-disulfide interchange reactions. The encoded protein has an N-terminal ER-signal sequence, a catalytically active thioredoxin domain, and a C-terminal ER-retention sequence. This protein plays a role in cell migration, cellular transformation and metastasis and is as a p53 inhibitor. As an ER-localized molecular chaperone, it plays a role in the folding, trafficking, and assembly of cysteine-rich transmembrane receptors and the cysteine-rich intestinal gylcoprotein mucin. This gene has been implicated in inflammatory bowel disease and cancer progression. [provided by RefSeq, Mar 2017]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:anterior gradient protein 2 homolog
Source:NCBIAccessed: 15 March, 2017


What does this gene/protein do?
Show (6)

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 15 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Gene Expression Profiling
  • Pancreatic Cancer
  • Multivariate Analysis
  • Lymphatic Metastasis
  • Messenger RNA
  • Lung Cancer
  • Immunohistochemistry
  • Estrogen Receptors
  • Neoplasm Proteins
  • Carrier Proteins
  • Ovarian Cancer
  • Cancer Gene Expression Regulation
  • Neoplasm Metastasis
  • Cell Proliferation
  • Biomarkers, Tumor
  • Proteins
  • Breast Cancer
  • Gene Expression
  • Staging
  • Xenopus Proteins
  • Oligonucleotide Array Sequence Analysis
  • Sequence Alignment
  • Western Blotting
  • Estrogen Receptor alpha
  • Antineoplastic Agents
  • Uroplakin II
  • Prostate Cancer
  • siRNA
  • Drug Resistance
  • RNA Interference
  • Proportional Hazards Models
  • Colorectal Cancer
  • Disease Progression
  • Sequence Analysis, Protein
  • Adenocarcinoma
  • Amino Acid Sequence
  • Cell Movement
  • Molecular Sequence Data
  • Transfection
  • Chromosome 7
Tag cloud generated 15 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: AGR2 (cancer-related)

Uthaisar K, Vaeteewoottacharn K, Seubwai W, et al.
Establishment and characterization of a novel human cholangiocarcinoma cell line with high metastatic activity.
Oncol Rep. 2016; 36(3):1435-46 [PubMed] Related Publications
Cholangiocarcinoma (CCA) is a highly metastatic tumor, and the lung is a common site of metastasis. A greater understanding of the biology of metastases is needed to improve treatment outcomes. Herein, a highly metastatic human CCA subline, KKU-213L5 from an original cell line, KKU-213 that has marginally metastatic ability, was established and characterized. KKU-213L5 was selected in vivo through the fifth serial passage of pulmonary metastasized tissues via tail-vein injection in NOD/scid/Jak3 mice. The metastatic abilities of the KKU-213L5 cells were compared with the parental line in vitro and in vivo. The expression profile of this metastatic cell line was determined using real-time PCR. KKU-213L5 cells were found to possess higher metastatic phenotypes, i.e., growth rates, stem cell surface markers (CD133), migration and invasion characteristics when compared with the parental cells. Compared to the KKU-213 cells, KKU-213L5 cells formed larger tumors in subcutaneous xenografted mice and had a >10-fold increase in lung metastases in the tail-vein injected metastatic mouse model. Mice injected intravenously with KKU-213L5 cells had a significantly shorter survival. Analysis of the expressed genes related to progression of cancer revealed significant upregulation of anterior gradient protein-2 (AGR2) and suppression of KiSS-1 in the KKU-213L5 cells. The association of these two genes with metastasis was affirmed in CCA patient tissues since increased AGR2 expression and decreased KiSS-1 expression were found in higher stage patient tumors. In conclusion, a highly metastatic human CCA cell line was established and characterized. It is plausible that the differential expression between the parental KKU-213 and highly metastatic KKU-213L5 cells may be beneficial to classify novel genes associated with metastasis. The KKU-213L5 cell line should serve as a valued device for discovering the molecular mechanisms of CCA metastasis and enabling the search for an effective therapy for the unmet clinical need in CCA.

Matsuda Y, Miura K, Yamane J, et al.
SERPINI1 regulates epithelial-mesenchymal transition in an orthotopic implantation model of colorectal cancer.
Cancer Sci. 2016; 107(5):619-28 [PubMed] Free Access to Full Article Related Publications
An increasingly accepted concept is that the progression of colorectal cancer is accompanied by epithelial-mesenchymal transition (EMT). In our study, in order to characterize the properties of EMT in 16 colorectal cancer cell lines, the cells were first orthotopically implanted into nude mice, and the tumors in vivo, as well as cells cultured in vitro, were immunostained for EMT markers. The immunostaining revealed that seven of the cells had an epithelial phenotype with a high expression of E-cadherin, whereas other cells showed opposite patterns, such as a high expression of vimentin (CX-1, COLO205, CloneA, HCT116, and SW48). Among the cells expressing vimentin, some expressed vimentin in the orthotopic tumors but not in the cultured cells (SW480, SW620, and COLO320). We evaluated these findings in combination with microarray analyses, and selected five genes: CHST11, SERPINI1, AGR2, FBP1, and FOXA1. Next, we downregulated the expression of SERPINI1 with siRNA in the cells, the results of which showed reverse-EMT changes at the protein level and in the cellular morphology. Along with immunohistochemical analyses, we confirmed the effect of the intracellular and secreted SERPINI1 protein of SW620 cells, which supported the importance of SERPINI1 in EMT. The development of therapeutic strategies targeting EMT is ongoing, including methods targeting the transforming growth factor-β signaling pathway as well as the Wnt pathway. SERPINI1 is an important regulator of EMT. Our findings help to elucidate the signaling pathways of EMT, hopefully clarifying therapeutic pathways as well.

Willis S, Villalobos VM, Gevaert O, et al.
Single Gene Prognostic Biomarkers in Ovarian Cancer: A Meta-Analysis.
PLoS One. 2016; 11(2):e0149183 [PubMed] Free Access to Full Article Related Publications
PURPOSE: To discover novel prognostic biomarkers in ovarian serous carcinomas.
METHODS: A meta-analysis of all single genes probes in the TCGA and HAS ovarian cohorts was performed to identify possible biomarkers using Cox regression as a continuous variable for overall survival. Genes were ranked by p-value using Stouffer's method and selected for statistical significance with a false discovery rate (FDR) <.05 using the Benjamini-Hochberg method.
RESULTS: Twelve genes with high mRNA expression were prognostic of poor outcome with an FDR <.05 (AXL, APC, RAB11FIP5, C19orf2, CYBRD1, PINK1, LRRN3, AQP1, DES, XRCC4, BCHE, and ASAP3). Twenty genes with low mRNA expression were prognostic of poor outcome with an FDR <.05 (LRIG1, SLC33A1, NUCB2, POLD3, ESR2, GOLPH3, XBP1, PAXIP1, CYB561, POLA2, CDH1, GMNN, SLC37A4, FAM174B, AGR2, SDR39U1, MAGT1, GJB1, SDF2L1, and C9orf82).
CONCLUSION: A meta-analysis of all single genes identified thirty-two candidate biomarkers for their possible role in ovarian serous carcinoma. These genes can provide insight into the drivers or regulators of ovarian cancer and should be evaluated in future studies. Genes with high expression indicating poor outcome are possible therapeutic targets with known antagonists or inhibitors. Additionally, the genes could be combined into a prognostic multi-gene signature and tested in future ovarian cohorts.

Hu R, Huffman KE, Chu M, et al.
Quantitative Secretomic Analysis Identifies Extracellular Protein Factors That Modulate the Metastatic Phenotype of Non-Small Cell Lung Cancer.
J Proteome Res. 2016; 15(2):477-86 [PubMed] Free Access to Full Article Related Publications
Lung cancer is the leading cause of cancer-related deaths for men and women in the United States, with non-small cell lung cancer (NSCLC) representing 85% of all diagnoses. Late stage detection, metastatic disease and lack of actionable biomarkers contribute to the high mortality rate. Proteins in the extracellular space are known to be critically involved in regulating every stage of the pathogenesis of lung cancer. To investigate the mechanism by which secreted proteins contribute to the pathogenesis of NSCLC, we performed quantitative secretomic analysis of two isogenic NSCLC cell lines (NCI-H1993 and NCI-H2073) and an immortalized human bronchial epithelial cell line (HBEC3-KT) as control. H1993 was derived from a chemo-naïve metastatic tumor, while H2073 was derived from the primary tumor after etoposide/cisplatin therapy. From the conditioned media of these three cell lines, we identified and quantified 2713 proteins, including a series of proteins involved in regulating inflammatory response, programmed cell death and cell motion. Gene Ontology (GO) analysis indicates that a number of proteins overexpressed in H1993 media are involved in biological processes related to cancer metastasis, including cell motion, cell-cell adhesion and cell migration. RNA interference (RNAi)-mediated knock down of a number of these proteins, including SULT2B1, CEACAM5, SPRR3, AGR2, S100P, and S100A14, leads to dramatically reduced migration of these cells. In addition, meta-analysis of survival data indicates NSCLC patients whose tumors express higher levels of several of these secreted proteins, including SULT2B1, CEACAM5, SPRR3, S100P, and S100A14, have a worse prognosis. Collectively, our results provide a potential molecular link between deregulated secretome and NSCLC cell migration/metastasis. In addition, the identification of these aberrantly secreted proteins might facilitate the development of biomarkers for early detection of this devastating disease.

Xu C, Liu Y, Xiao L, et al.
The involvement of anterior gradient 2 in the stromal cell-derived factor 1-induced epithelial-mesenchymal transition of glioblastoma.
Tumour Biol. 2016; 37(5):6091-7 [PubMed] Related Publications
In recent years, it has been widely identified that the stromal cell-derived factor 1 (SDF-1) and anterior gradient 2 (AGR2) were implicated in the development of epithelial-mesenchymal transition (EMT) in a variety of cancers. However, the involvement of SDF-1-AGR2 pathway in the EMT of glioblastoma has not been investigated. In the present study, the in vitro assays were used to investigate the role of AGR2 in cell cycle, migration, and invasion. We found that the expressions of AGR2 and chemokine (C-X-C motif) receptor 4 (CXCR4) were obviously upregulated in glioblastoma cells T98G, A172, U87, and U251 than those in normal human astrocytes (NHA) (all p < 0.01), among which both U87 and U251 cells presented the highest expression (p > 0.05). Western blot revealed that SDF-1 induced the expression of p-AKT, AGR2, and EMT markers (N-cadherin, matrix metalloproteinase-2 (MMP2), and Slug) in a dose-dependent manner in U87 and U251 cells. However, the depletion of AGR2 reversed SDF-1-induced upregulation of EMT markers rather than p-AKT. Furthermore, functional analysis identified that knockdown of AGR2 induced cell cycle arrest in G0/G1 phase and suppressed the migration and invasion of U87 and U251 cells. Taken together, SDF-1-CXCR4 pathway induced the expression of AGR2 to control the progression of EMT likely via AKT pathway in the development of glioblastoma. Our findings lay a promising foundation for the SDF-1-AGR2 axis-targeting therapy in patients with glioblastoma.

Jézéquel P, Sharif Z, Lasla H, et al.
Gene-expression signature functional annotation of breast cancer tumours in function of age.
BMC Med Genomics. 2015; 8:80 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Breast cancer biological characteristics change as age advances. Today, there is a lack of knowledge regarding age-specific molecular alterations that characterize breast tumours, notably in elderly patients. The vast majority of studies that aimed at exploring breast cancer in function of age are based on clinico-pathological data. Gene-expression signatures (GES), which in some ways capture biological information in a non-reductionist manner, represent powerful tools able to explore tumour heterogeneity.
METHODS: Twenty-five GES were used for functional annotation of breast tumours in function of age: five for molecular subtyping, seven for immune response, three for metabolism, seven for critical pathways in cancer and three for prognosis. Affymetrix® genomics datasets were exclusively used to avoid cross-platform normalization issues. Available corresponding clinico-pathological data were also retrieved and analysed.
RESULTS: Fifteen publicly available datasets were pooled for a total of 2378 breast cancer patients (whole cohort), out of whom 1413 were of Caucasian origin. Three age groups were defined: ≤ 40 years (AG1), > 40 to < 70 years (AG2) and ≥ 70 years (AG3). We confirmed that age influenced the incidence of molecular subtypes. We found a significant growing incidence of luminal B and a decreasing kinetics for basal-like in function of age. We showed that AG3 luminal B tumours were less aggressive than AG1 luminal B tumours based on different GES (iron metabolism, mitochondrial oxidative phosphorylation and reactive stroma), recurrence score prognostic GES and histological grade (SBR). Contrary to tumours of young patients, tumours of elderly patients concentrated favourable GES scores: high oestrogen receptor and mitochondrial oxidative phosphorylation, low proliferation, basal-like, glycolysis, chromosomal instability and iron metabolism, and low GES prognostic scores (van't Veer 70-GES, genomic grade index and recurrence score).
CONCLUSIONS: Functional annotation of breast tumours by means of 25 GES demonstrated a decreasing aggressiveness of breast tumours in function of age. This strategy, which can be strengthened by increasing the number of representative GES to gain more insight into biological systems involved in this disease, provides a framework to develop rational therapeutic strategies in function of age.

Alavi M, Mah V, Maresh EL, et al.
High expression of AGR2 in lung cancer is predictive of poor survival.
BMC Cancer. 2015; 15:655 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Anterior gradient 2 (AGR2) is a protein disulfide isomerase-like protein widely expressed in many normal tissues as well as cancers. In our study, non-neoplastic bronchial epithelial cells as well as non-small cell lung cancer (NSCLC) cells express AGR2 protein.
METHODS: AGR2 expression was analyzed on lung tissue microarrays. Tumor staining was correlated with clinical outcomes.
RESULTS: On a lung cancer tissue microarray using immunohistochemistry, expression levels in cancer showed generally decreasing intensities in order from adenocarcinomas with mucinous components, other adenocarcinomas, squamous carcinomas, to large cell carcinomas. The study cohort was comprised of 400 cases. As a group, there was a slight trend of lower expression with increasing tumor grade. AGR2 expression level was a significant predictor of overall survival in younger patients only. Patients under 65 with lower levels showed a significantly better survival for both men and women. Patients over 65, in contrast, showed no such trend.
CONCLUSIONS: Nearly all NSCLC tumors show AGR2 expression. Lung cancer expression of AGR2 has prognostic value for younger patients.

Zhang M, Ye G, Li J, Wang Y
Recent advance in molecular angiogenesis in glioblastoma: the challenge and hope for anti-angiogenic therapy.
Brain Tumor Pathol. 2015; 32(4):229-36 [PubMed] Related Publications
Glioblastoma (GBM) is the most highly malignant brain tumor in the human central nerve system. In this paper, we review new and significant molecular findings on angiogenesis and possible resistance mechanisms. Expression of a number of genes and regulators has been shown to be upregulated in GBM microvessel cells, such as interleukin-8, signal transducer and activator of transcription 3, Tax-interacting protein-1, hypoxia induced factor-1 and anterior gradient protein 2. The regulator factors that may strongly promote angiogenesis by promoting endothelial cell metastasis, changing the microenvironment, enhancing the ability of resistance to anti-angiogenic therapy, and that inhibit angiogenesis are reviewed. Based on the current knowledge, several potential targets and strategies are proposed for better therapeutic outcomes, such as its mRNA interference of DII4-Notch signaling pathway and depletion of b1 integrin expression. We also discuss possible mechanisms underlying the resistance to anti-angiogenesis and future directions and challenges in developing new targeted therapy for GBM.

Noguchi S, Eitoku M, Moriya S, et al.
Regulation of Gene Expression by Sodium Valproate in Epithelial-to-Mesenchymal Transition.
Lung. 2015; 193(5):691-700 [PubMed] Related Publications
PURPOSE: Epithelial-to-mesenchymal transition (EMT) is an important mechanism in cancer metastasis and pulmonary fibrosis. Previous studies demonstrated effect of histone H3 and H4 acetylation in cancer and pulmonary fibrosis, so we hypothesized that histone modification might play a crucial role in gene regulation during EMT. In this study, we investigated the mechanism behind EMT by analyzing comprehensive gene expression and the effect of sodium valproate (VPA), a class I histone deacetylase inhibitory drug, on histone modification.
METHODS: EMT was induced in human alveolar epithelial cells (A549) using 5 ng/mL of transforming growth factor (TGF)-β1. Various concentrations of VPA were then administered, and Western blotting was used to analyze histone acetylation or methylation. Comprehensive gene expression analysis was carried out by RNA sequencing, and chromatin immunoprecipitation was performed with an anti-acetyl histone H3 lysine 27 antibody.
RESULTS: TGF-β1 stimulation led to a decrease in histone acetylation, especially that of histone H3K27, and H3K27ac localization was decreased at particular gene loci. This decrease was recovered by VPA treatment, which also up-regulated the mRNA expression of genes down-regulated by TGF-β1, and correlated with the localization of H3K27ac. However, genes up-regulated by TGF-β1 stimulation were not suppressed by VPA, with the exception of COL1A1.
CONCLUSIONS: Histone acetylation was down-regulated by TGF-β1 stimulation in A549 cells. VPA partially inhibited EMT and the decrease of histone acetylation, which plays an important role in the progression of EMT.

Li Z, Wu Z, Chen H, et al.
Induction of anterior gradient 2 (AGR2) plays a key role in insulin-like growth factor-1 (IGF-1)-induced breast cancer cell proliferation and migration.
Med Oncol. 2015; 32(6):577 [PubMed] Free Access to Full Article Related Publications
Anterior gradient 2 (AGR2) is a promising anti-tumor target associated with estrogen receptor expression and metastatic progression of breast cancer. Insulin-like growth factor-1 (IGF-1) is another potent factor that stimulates breast cancer progression and mediates anti-estrogen drug resistance. However, the precise mechanism and connections between these two factors in breast cancer drug resistance have not been fully elucidated. Here, for the first time, we decipher that IGF-1 remarkably induces AGR2 in the MCF7 cell line, through an estrogen response element (ERE) between -802 and -808 bp and a leucine zipper transcription factor-binding site located between -972 and -982 bp on the AGR2 promoter. We also found that the ERK1/2 and AKT pathways mediate estrogen receptor-α at the upstream of ERE and that the JNK pathway activates the leucine zipper site through the c-Jun/c-Fos complex. Additionally, our data suggest that knockdown of AGR2 reduces IGF-1-induced cell proliferation, migration and cell cycle progression. Therefore, we report that AGR2 is a key modulator involved in IGF-1-induced breast cancer development. We propose that the identification of the mechanism linking the IGF-1/insulin signal and AGR2 promoter activation is important, because it provides insights into the development of anti-breast cancer drugs.

Brychtova V, Mohtar A, Vojtesek B, Hupp TR
Mechanisms of anterior gradient-2 regulation and function in cancer.
Semin Cancer Biol. 2015; 33:16-24 [PubMed] Related Publications
Proteins targeted to secretory pathway enter the endoplasmic reticulum where they undergo post-translational modification and subsequent quality control executed by exquisite catalysts of protein folding, protein disulphide isomerases (PDIs). These enzymes can often provide strict conformational protein folding solutions to highly cysteine-rich cargo as they facilitate disulphide rearrangement in the endoplasmic reticulum. Under conditions when PDI substrates are not isomerised properly, secreted proteins can accumulate in the endoplasmic reticulum leading to endoplasmic reticulum stress initiation with implications for human disease development. Anterior Gradient-2 (AGR2) is an endoplasmic reticulum-resident PDI superfamily member that has emerged as a dominant effector of basic biological properties in vertebrates including blastoderm formation and limb regeneration. AGR2 perturbation in mammals influences disease processes including cancer progression and drug resistance, asthma, and inflammatory bowel disease. This review will focus on the molecular characteristics, function, and regulation of AGR2, views on its emerging biological functions and misappropriation in disease, and prospects for therapeutic intervention into endoplasmic reticulum-resident protein folding pathways for improving the treatment of human disease.

Garczyk S, von Stillfried S, Antonopoulos W, et al.
AGR3 in breast cancer: prognostic impact and suitable serum-based biomarker for early cancer detection.
PLoS One. 2015; 10(4):e0122106 [PubMed] Free Access to Full Article Related Publications
Blood-based early detection of breast cancer has recently gained novel momentum, as liquid biopsy diagnostics is a fast emerging field. In this study, we aimed to identify secreted proteins which are up-regulated both in tumour tissue and serum samples of breast cancer patients compared to normal tissue and sera. Based on two independent tissue cohorts (n = 75 and n = 229) and one serum cohort (n = 80) of human breast cancer and healthy serum samples, we characterised AGR3 as a novel potential biomarker both for breast cancer prognosis and early breast cancer detection from blood. AGR3 expression in breast tumours is significantly associated with oestrogen receptor α (P<0.001) and lower tumour grade (P<0.01). Interestingly, AGR3 protein expression correlates with unfavourable outcome in low (G1) and intermediate (G2) grade breast tumours (multivariate hazard ratio: 2.186, 95% CI: 1.008-4.740, P<0.05) indicating an independent prognostic impact. In sera analysed by ELISA technique, AGR3 protein concentration was significantly (P<0.001) elevated in samples from breast cancer patients (n = 40, mainly low stage tumours) compared to healthy controls (n = 40). To develop a suitable biomarker panel for early breast cancer detection, we measured AGR2 protein in human serum samples in parallel. The combined AGR3/AGR2 biomarker panel achieved a sensitivity of 64.5% and a specificity of 89.5% as shown by receiver operating characteristic (ROC) curve statistics. Thus our data clearly show the potential usability of AGR3 and AGR2 as biomarkers for blood-based early detection of human breast cancer.

Ma SR, Wang WM, Huang CF, et al.
Anterior gradient protein 2 expression in high grade head and neck squamous cell carcinoma correlated with cancer stem cell and epithelial mesenchymal transition.
Oncotarget. 2015; 6(11):8807-21 [PubMed] Free Access to Full Article Related Publications
Anterior gradient protein 2 (AGR2) is a novel biomarker with potential oncogenic role. We sought to investigate the diagnostic and prognostic role of AGR2 on head and neck squamous cell carcinoma (HNSCC) with an emphasis on its correlation of cancer stemloid cells (CSC) and epithelial mesenchymal transition (EMT). We found that AGR2 protein levels were higher in HNSCC than in normal oral mucosa. High levels of AGR2 were associated with the T category, pathological grade and lymph node metastasis of HNSCC. Expression of AGR2 increased in recurring HNSCC after radiotherapy and in post cisplatin-based chemotherapeutic tissues. In HNSCC cell lines, knock-down of AGR2 induced apoptosis, reduced sphere formation, and down-regulated Survivin, Cyclin D1, Bcl2, Bcl2l1, Slug, Snail, Nanog and Oct4. In addition, over-expressed AGR2 in transgenic mice with spontaneous HNSCC was associated with lost function of Tgfbr1 and/ or lost function of Pten. In vitro knockdown TGFBR1 in HNSCC cell lines increased AGR2 expression. These results suggest that AGR2 is involved in EMT and self-renewal of CSC and may present a potential therapeutic target (oncotarget) for HNSCC.

Mostert B, Sieuwerts AM, Bolt-de Vries J, et al.
mRNA expression profiles in circulating tumor cells of metastatic colorectal cancer patients.
Mol Oncol. 2015; 9(4):920-32 [PubMed] Related Publications
INTRODUCTION: The molecular characterization of circulating tumor cells (CTCs) is a promising tool for the repeated and non-invasive evaluation of predictive and prognostic factors. Challenges associated with CTC characterization using the only FDA approved method for CTC enumeration, the CellSearch technique, include the presence of an excess of leukocytes in CTC-enriched blood fractions. Here we aimed to identify colorectal tumor-specific gene expression levels in the blood of patients with and without detectable CTCs according to CellSearch criteria.
MATERIALS AND METHODS: Blood of 30 healthy donors (HDs) and 142 metastatic colorectal cancer (mCRC) patients was subjected to CellSearch CTC enumeration and isolation. In all samples, 95 mRNAs were measured by reverse transcriptase quantitative PCR (RT-qPCR). HD blood samples and patient samples with three or more CTCs were compared to identify CTC-specific mRNAs. Patient samples without detectable CTCs were separately analyzed.
RESULTS: Thirty-four CTC-specific mRNAs were higher expressed in patients with ≥3 CTCs compared with HDs (Mann-Whitney U-test P < 0.05). Among patients without detectable CTCs, a HD-unlike subgroup was identified which could be distinguished from HDs by the expression of epithelial genes such as KRT19, KRT20 and AGR2. Also, in an independent patient set, a similar HD-unlike group could be identified among the patients without detectable CTCs according to the CellSearch system.
CONCLUSION: Extensive molecular characterization of colorectal CTCs is feasible and a subgroup of patients without detectable CTCs according to CellSearch criteria bears circulating tumor load, which may have clinical consequences. This CTC-specific gene panel for mCRC patients may enable the exploration of CTC characterization as a novel means to further individualize cancer treatment.

Arumugam T, Deng D, Bover L, et al.
New Blocking Antibodies against Novel AGR2-C4.4A Pathway Reduce Growth and Metastasis of Pancreatic Tumors and Increase Survival in Mice.
Mol Cancer Ther. 2015; 14(4):941-51 [PubMed] Free Access to Full Article Related Publications
Anterior gradient 2 (AGR2) promotes cancer growth, metastasis, and resistance to therapy via unknown mechanisms. We investigated the effects of extracellular AGR2 signaling through the orphan glycosylphosphatidylinositol-linked receptor C4.4A in pancreatic ductal adenocarcinoma (PDAC). Proliferation, migration, invasion, and apoptosis were measured using colorimetric, Boyden chamber, and FACS analyses. We developed blocking mAbs against AGR2 and C4.4A and tested their effects, along with siRNAs, on cancer cell functions and on orthotopic tumors in nude mice. Extracellular AGR2 stimulated proliferation, migration, invasion, and chemoresistance of PDAC cell lines. AGR2 interacted with C4.4A in cell lysates and mixtures of recombinant proteins. Knockdown of C4.4A reduced migration and resistance to gemcitabine. PDAC tissues, but not adjacent healthy pancreatic tissues, expressed high levels of AGR2 and C4.4A. AGR2 signaling through C4.4A required laminins 1 or 5 and integrin β1. Administration of antibodies against AGR2 and C4.4A reduced growth and metastasis and caused regression of aggressive xenograft tumors, leading to increased survival of mice. These data support a model in which AGR2 binds and signals via C4.4A in an autocrine loop and promotes the growth of pancreas tumors in mice. Blocking mAbs against AGR2 and C4.4A may have therapeutic potential against PDAC.

Narumi S, Miki Y, Hata S, et al.
Anterior gradient 2 is correlated with EGFR mutation in lung adenocarcinoma tissues.
Int J Biol Markers. 2015; 30(2):e234-42 [PubMed] Related Publications
BACKGROUND: Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) has demonstrated a promising therapeutic response in lung adenocarcinoma patients with EGFR gene mutations. However, the predictive factors for this therapy have not been established, except for the EGFR gene mutation status of carcinoma cells.
METHODS: We first performed microarray analysis in EGFR-TKI-sensitive lung adenocarcinoma cell lines. The results indicated anterior gradient 2 (AGR2) as a potential surrogate marker of EGFR-TKI. Therefore, we then evaluated the correlation between the status of AGR2 immunoreactivity and clinicopathological factors including overall survival (OS), progression-free survival (PFS) and clinical response to EGFR-TKI, in 147 cases of surgically resected lung adenocarcinoma. The biological significance of AGR2 was further evaluated by transfecting small interfering RNA (siRNA) against AGR2 in these cells.
RESULTS: The status of AGR2 immunoreactivity was significantly higher in lung adenocarcinoma cases with EGFR gene mutations than in those with the wild type (p<0.0001), but there were no significant differences in OS, PFS and response of EGFR-TKI between the AGR2 high and low carcinoma cases. Knockdown of AGR2 gene expression following siRNA transfection resulted in a significantly lower response to EGFR-TKI in EGFR-mutated PC-3.
CONCLUSIONS: AGR2 could serve as an adjunctive surrogate protein marker possibly reflecting EGFR gene mutations in lung adenocarcinoma patients. Results from in vitro analysis indicated that AGR2 could be a potential clinical biomarker of EGFR-TKI therapeutic sensitivity in lung adenocarcinoma cells.

Chen T, Sun L, He C, et al.
Serum OPN expression for identification of gastric cancer and atrophic gastritis and its influencing factors.
PLoS One. 2014; 9(12):e114005 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Most studies have found that osteopontin (OPN) expression level is related to the poor prognosis of gastric cancer. However, few studies have examined the relationship between OPN expression and gastric precancerous diseases, and the potential role of OPN in the formation and development of GC. We investigated the relationships between serum OPN levels and the risks of gastric cancer (GC) and its precancerous disease, to explore the diagnostic efficacy of serum OPN level for GC and atrophic gastritis and its influencing factors.
METHODS: A total of 1,452 patients were enrolled, including 609 with mild superficial gastritis (SG), 594 with atrophic gastritis (AG) and 249 with GC. The levels of serum OPN and serum Helicobacter pylori IgG antibody were detected by enzyme-linked immunosorbent assay.
RESULTS: Serum OPN levels increased from mild SG (1.99 ± 1.91 ng/ml) to AG (2.37 ± 2.27 ng/ml) to GC (5.94 ± 4.52 ng/ml) (P ≤ 0.002), along with increasing severity of gastric disease. OPN levels were significantly higher in patients with GC compared with the non-cancer population (2.17 ± 2.10, P < 0.0001). Serum OPN level was positively correlated with age and was higher in men than women, but was not correlated with H. pylori infection status. The area under the receiver operating characteristic curve was 0.805, the optimal cutoff was 2.56 ng/ml and the sensitivity and specificity were 74.3% and 71.8%, respectively, for the ability of serum OPN to discriminate GC.
CONCLUSIONS: Serum OPN expression was closely related to the risks of GC and AG, and it might be a useful marker for the discrimination of GC. OPN level was positively correlated with age and male sex, but was not affected by H. pylori infection, and it was promoted by smoking and drinking, in patients with mild SG.

Mizuuchi Y, Aishima S, Ohuchida K, et al.
Anterior gradient 2 downregulation in a subset of pancreatic ductal adenocarcinoma is a prognostic factor indicative of epithelial-mesenchymal transition.
Lab Invest. 2015; 95(2):193-206 [PubMed] Related Publications
Anterior gradient 2 (AGR2), a member of the protein disulfide isomerase family, has been implicated in various cancers including pancreatic ductal adenocarcinoma (PDAC) and is known to promote cancer progression. However, the prognostic value of AGR2 expression and the interaction with epithelial-mesenchymal transition (EMT) remain unclear. We investigated the clinical significance of AGR2 and EMT markers in PDAC patients by immunohistochemical analyses. Although AGR2 expression was not observed in normal pancreas, all pancreatic precursor neoplastic lesions were positive for AGR2, even at the earliest stages, including pancreatic intraepithelial neoplasia-1A, AGR2 expression was reduced in 27.7% (54/195 cases) of PDAC patients. AGR2 downregulation correlated with EMT markers (vimentin overexpression and reduced membranous E-cadherin expression), high Union for International Cancer Control stage (P<0.0001), high histological cellular grade (P<0.0001), and adverse outcome (P<0.0001). In vitro, targeted silencing of AGR2 in cancer cells using siRNA reduced cell proliferation, colony formation, cell invasiveness, and migration, but did not alter EMT markers. To confer a more aggressive phenotype and induce EMT in PDAC cells, we co-cultured PDAC cell lines with primary-cultured pancreatic stellate cells (PSCs) and found that AGR2 was downregulated in co-cultured PDAC cells compared with PDAC monocultures. Treatment with transforming growth factor beta-1 (TGF-β), secreted from PSCs, decreased AGR2 expression, whereas inhibition of TGF-β signaling using recombinant soluble human TGF-β receptor type II and TGF-β-neutralizing antibodies restored AGR2 expression. We conclude that AGR2 downregulation is a useful prognostic marker, induced by EMT, and that secreted TGF-β from PSCs may partially contribute to AGR2 downregulation in PDAC patients. AGR2 downregulation does not induce EMT or a more aggressive phenotype, but is a secondary effect of these processes in advanced PDAC.

Haynes BP, Viale G, Galimberti V, et al.
Differences in expression of proliferation-associated genes and RANKL across the menstrual cycle in estrogen receptor-positive primary breast cancer.
Breast Cancer Res Treat. 2014; 148(2):327-35 [PubMed] Related Publications
The purpose of this study is to determine if there are differences in the expression of estrogen-regulated genes (ERGs), proliferation-associated genes and the progesterone effector RANKL, in premenopausal ER+ breast cancer as a result of the major changes in hormone levels that occur through the menstrual cycle. Primary ER+ tumours from 174 patients were assigned to one of three menstrual cycle windows: W1 (days 27-35 + 1-6), W2 (days 7-16) and W3 (days 17-26). RNA expression of 42 genes, including 24 putative genes associated with plasma E2 levels, seven proliferation genes and RANKL was measured. Expression of PGR, TFF1, GREB1 and PDZK1 followed the previously reported pattern: a higher level in W2 compared to W1 while W3 had an intermediate value, mirroring changes in plasma estradiol. Of the other 20 ERGs, four (RUNX1, AGR2, SERPINA3 and SERPINA5) showed significant differences (p = 0.009-0.049) in expression across the menstrual cycle. The expression of six of seven proliferation-associated genes varied across the cycle but differently from the ERGs, being 20-35 % lower in W3 compared to W1 and W2 (p = 0.004-0.031). Expression of RANKL was 2.5 to 3-fold highest in W3 (p = 0.0001) and negatively correlated to the expression of the proliferation-associated genes (r = -0.37; p < 0.0001). Expression of proliferation-associated genes and RANKL in ER+ breast tumours varies across the menstrual cycle showing a different rhythm to that of ERGs. This may affect the interpretation of gene expression profiles but may be exploitable as an endogenous test of endocrine responsiveness.

Kim SJ, Jun S, Cho HY, et al.
Knockdown of anterior gradient 2 expression extenuates tumor-associated phenotypes of SNU-478 ampulla of Vater cancer cells.
BMC Cancer. 2014; 14:804 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Anterior gradient 2 (AGR2) has been implicated in tumor-associated phenotypes such as cell viability, invasion and metastasis in various human cancers. However, the tumor promoting activity of AGR2 has not yet been determined in biliary tract cancers. Thus, we examined the expression of AGR2 and its tumor-promoting activity in biliary tract cancer cells in this study.
METHODS: Expression of AGR2 mRNA and protein was analyzed by real time RT-PCR and western blotting, respectively. MTT assay was employed to measure cell viability and pulsed BrdU incorporation by proliferating cells was monitored by flow cytometry. Soft agar colony formation assay and transwell invasion assay were employed to determine anchorage-independent growth and in vitro invasion of the tumor cells, respectively. In vivo tumor formation was examined by injection of tumor cells into immunocompromised mice subcutaneously. Statistical analysis was performed with 2-tailed unpaired Student's t-test for continuous data and with one-way ANOVA for multiple group comparisons. Bonferroni tests were used for post hoc 2-sample comparisons.
RESULTS: AGR2 mRNA was detected in SNU-245, SNU-478, and SNU-1196 cell lines, and its protein expression was confirmed in SNU-478 and SNU-245 cell lines by western blot analysis. Knockdown of AGR2 expression with an AGR2-specific short hairpin RNA (shRNA) in SNU-478, an ampulla of Vater cancer cell line resulted in decreased cell viability and in decreased anchorage-independent growth by 98%. The AGR2 knockdown also increased the sensitivity of the cells to chemotherapeutic drugs, including gemcitabine, 5-fluorouracil and cisplatin. In addition, SNU-478 cells expressing AGR2-shRNA failed to form detectable tumor xenografts in nude mice, whereas control cells formed tumors with an average size of 179 ± 84 mm3 in 3 weeks. Overexpression of AGR2 in SNU-869 cells significantly increased cell viability through enhanced cell proliferation and the number of Matrigel™-invading cells compared with AGR2-negative SNU-869 cells.
CONCLUSIONS: Our findings implicate that AGR2 expression augments tumor-associated phenotypes by increasing proliferative and invasive capacities of the ampulla of Vater cancer cells.

Neeb A, Hefele S, Bormann S, et al.
Splice variant transcripts of the anterior gradient 2 gene as a marker of prostate cancer.
Oncotarget. 2014; 5(18):8681-9 [PubMed] Free Access to Full Article Related Publications
Anterior gradient 2 (AGR2) is a gene predominantly expressed in mucus-secreting tissues or in endocrine cells. Its expression is drastically increased in tumors including prostate cancer. Here we investigated whether AGR2 transcript levels can be used as a biomarker to detect prostate cancer (PCa). Using a PCR-based approach, we could show that in addition to the wild-type (AGRwt long and short) transcripts, five other AGR2 splice variants (SV) (referred to as AGR2 SV-C, -E, -F, -G and -H) were present in cancer cell lines. In tissue biopsies, SV-H and AGR2wt (short) distinguished between benign and PCa (p ≤ 0.05 n = 32). In urine exosomes, AGR2 SV-G and SV-H outperformed serum PSA. Receiver operating characteristic (ROC) curves showed the highest discriminatory power of SV-G and SV-H in predicting PCa. AGR2 SV-G and SV-H are potential diagnostic biomarkers for the non-invasive detection of PCa using urine exosomes.

Kim SJ, Kim DH, Kang D, Kim JH
Expression of anterior gradient 2 is decreased with the progression of human biliary tract cancer.
Tohoku J Exp Med. 2014; 234(1):83-8 [PubMed] Related Publications
Biliary tract cancers include cancers of the gallbladder and extrahepatic bile ducts, and its prognosis is poor. The anterior gradient 2 (AGR2) is a protein disulfide isomerase and is highly expressed in various human cancers, such as breast, prostate and pancreas cancers. AGR2 is expressed in normal cholangiocytes and its expression is maintained during biliary carcinogenesis. However, the clinical significance of AGR2 expression in biliary tract cancer has not yet been assessed. Thus, we examined the expression of AGR2 protein in biliary tract tumors using immunohistochemistry and its association with various clinicopathologic parameters. This study included 100 patients who underwent surgery for biliary tract cancers: 46 men and 54 women with a mean and median age of 64.2 and 65.0 years, respectively. AGR2 expression was detected in ductal epithelial cells of the normal biliary tract and in 95% of biliary tract cancer tissues. While the AGR2 expression was not associated with cancer location, patient age, patient sex, degree of regional lymph node metastasis (N-status), or residual status, the AGR2 expression level was decreased with increased tumor size (T-status, p = 0.006) and progression of tumor stage (p = 0.009). Moreover, well-differentiated cancers tended to show higher AGR2 expression than poorly differentiated cancers (p = 0.068); in fact, AGR2 expression was not associated with patient survival (Kaplan-Meier analysis, p = 0.415). Thus, AGR2 is of limited value as a prognostic marker for biliary tract cancer. In conclusion, the expression of AGR2 is decreased with the progression of biliary tract cancer.

Wright TM, Wardell SE, Jasper JS, et al.
Delineation of a FOXA1/ERα/AGR2 regulatory loop that is dysregulated in endocrine therapy-resistant breast cancer.
Mol Cancer Res. 2014; 12(12):1829-39 [PubMed] Free Access to Full Article Related Publications
UNLABELLED: Tamoxifen, a selective estrogen receptor (ER) modulator (SERM), remains a frontline clinical therapy for patients with ERα-positive breast cancer. However, the relatively rapid development of resistance to this drug in the metastatic setting remains an impediment to a durable response. Although drug resistance likely arises by many different mechanisms, the consensus is that most of the implicated pathways facilitate the outgrowth of a subpopulation of cancer cells that can either recognize tamoxifen as an agonist or bypass the regulatory control of ERα. Notable in this regard is the observation here and in other studies that expression of anterior gradient homology 2 (AGR2), a known proto-oncogene and disulfide isomerase, was induced by both estrogen (17β-estradiol, E2) and 4-hydroxytamoxifen (4OHT) in breast cancer cells. The importance of AGR2 expression is highlighted here by the observation that (i) its knockdown inhibited the growth of both tamoxifen-sensitive and -resistant breast cancer cells and (ii) its increased expression enhanced the growth of ERα-positive tumors in vivo and increased the migratory capacity of breast cancer cells in vitro. Interestingly, as with most ERα target genes, the expression of AGR2 in all breast cancer cells examined requires the transcription factor FOXA1. However, in tamoxifen-resistant cells, the expression of AGR2 occurs in a constitutive manner, requiring FOXA1, but loses its dependence on ER. Taken together, these data define the importance of AGR2 in breast cancer cell growth and highlight a mechanism where changes in FOXA1 activity obviate the need for ER in the regulation of this gene.
IMPLICATIONS: These findings reveal the transcriptional interplay between FOXA1 and ERα in controlling AGR2 during the transition from therapy-sensitive to -resistant breast cancer and implicate AGR2 as a relevant therapeutic target.

Souchek JJ, Baine MJ, Lin C, et al.
Unbiased analysis of pancreatic cancer radiation resistance reveals cholesterol biosynthesis as a novel target for radiosensitisation.
Br J Cancer. 2014; 111(6):1139-49 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Despite its promise as a highly useful therapy for pancreatic cancer (PC), the addition of external beam radiation therapy to PC treatment has shown varying success in clinical trials. Understanding PC radioresistance and discovery of methods to sensitise PC to radiation will increase patient survival and improve quality of life. In this study, we identified PC radioresistance-associated pathways using global, unbiased techniques.
METHODS: Radioresistant cells were generated by sequential irradiation and recovery, and global genome cDNA microarray analysis was performed to identify differentially expressed genes in radiosensitive and radioresistant cells. Ingenuity pathway analysis was performed to discover cellular pathways and functions associated with differential radioresponse and identify potential small-molecule inhibitors for radiosensitisation. The expression of FDPS, one of the most differentially expressed genes, was determined in human PC tissues by IHC and the impact of its pharmacological inhibition with zoledronic acid (ZOL, Zometa) on radiosensitivity was determined by colony-forming assays. The radiosensitising effect of Zol in vivo was determined using allograft transplantation mouse model.
RESULTS: Microarray analysis indicated that 11 genes (FDPS, ACAT2, AG2, CLDN7, DHCR7, ELFN2, FASN, SC4MOL, SIX6, SLC12A2, and SQLE) were consistently associated with radioresistance in the cell lines, a majority of which are involved in cholesterol biosynthesis. We demonstrated that knockdown of farnesyl diphosphate synthase (FDPS), a branchpoint enzyme of the cholesterol synthesis pathway, radiosensitised PC cells. FDPS was significantly overexpressed in human PC tumour tissues compared with healthy pancreas samples. Also, pharmacologic inhibition of FDPS by ZOL radiosensitised PC cell lines, with a radiation enhancement ratio between 1.26 and 1.5. Further, ZOL treatment resulted in radiosensitisation of PC tumours in an allograft mouse model.
CONCLUSIONS: Unbiased pathway analysis of radioresistance allowed for the discovery of novel pathways associated with resistance to ionising radiation in PC. Specifically, our analysis indicates the importance of the cholesterol synthesis pathway in PC radioresistance. Further, a novel radiosensitiser, ZOL, showed promising results and warrants further study into the universality of these findings in PC, as well as the true potential of this drug as a clinical radiosensitiser.

Di Maro G, Salerno P, Unger K, et al.
Anterior gradient protein 2 promotes survival, migration and invasion of papillary thyroid carcinoma cells.
Mol Cancer. 2014; 13:160 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Through a transcriptome microarray analysis, we have isolated Anterior gradient protein 2 (AGR2) as a gene up-regulated in papillary thyroid carcinoma (PTC). AGR2 is a disulfide isomerase over-expressed in several human carcinomas and recently linked to endoplasmic reticulum (ER) stress. Here, we analyzed the expression of AGR2 in PTC and its functional role.
METHODS: Expression of AGR2 was studied by immunohistochemistry and real time PCR in normal thyroids and in PTC samples. The function of AGR2 was studied by knockdown in PTC cells and by ectopic expression in non-transformed thyroid cells. The role of AGR2 in the ER stress was analyzed upon treatment of cells, expressing or not AGR2, with Bortezomib and analyzing by Western blot the expression levels of GADD153.
RESULTS: PTC over-expressed AGR2 at mRNA and protein levels. Knockdown of AGR2 in PTC cells induced apoptosis and decreased migration and invasion. Ectopic expression of AGR2 in non-transformed human thyroid cells increased migration and invasion and protected cells from ER stress induced by Bortezomib.
CONCLUSIONS: AGR2 is a novel marker of PTC and plays a role in thyroid cancer cell survival, migration, invasion and protection from ER stress.

Huang J, Wang L, Jiang M, et al.
AGR2-mediated lung adenocarcinoma metastasis novel mechanism network through repression with interferon coupling cytoskeleton to steroid metabolism-dependent humoral immune response.
Cell Immunol. 2014; 290(1):102-6 [PubMed] Related Publications
7 anterior gradient homolog 2 (AGR2)-inhibited different molecular mutual positive correlation network was constructed in lung adenocarcinoma compared with human normal adjacent tissues by 17 overlapping molecules of 358 GRNInfer and 19 Pearson (AGR2 CC⩽-0.25). Based on GO, KEGG, GenMAPP, BioCarta and disease databases, we determined AGR2-mediated lung adenocarcinoma metastasis through repression with cytoskeleton of MAST1; steroid metabolism of SOAT2; humoral immune response of POU2AF1; interferon alpha-inducible of IFI6; immunoglobulin of IGKC_3, CTA_246H3.1. Thus we proposed AGR2-mediated lung adenocarcinoma metastasis novel mechanism network through repression with interferon coupling cytoskeleton to steroid metabolism-dependent humoral immune response.

Sung HY, Choi EN, Lyu D, et al.
Aberrant hypomethylation-mediated AGR2 overexpression induces an aggressive phenotype in ovarian cancer cells.
Oncol Rep. 2014; 32(2):815-20 [PubMed] Related Publications
The metastatic properties of cancer cells result from genetic and epigenetic alterations that lead to the abnormal expression of key genes regulating tumor phenotypes. Recent discoveries suggest that aberrant DNA methylation provides cancer cells with advanced metastatic properties; however, the precise regulatory mechanisms controlling metastasis-associated genes and their roles in metastatic transformation are largely unknown. We injected SK-OV-3 human ovarian cancer cells into the perineum of nude mice to generate a mouse model that mimics human ovarian cancer metastasis. We analyzed the mRNA expression and DNA methylation profiles in metastasized tumor tissues in the mice. The pro-oncogenic anterior gradient 2 (AGR2) gene showed increased mRNA expression and hypomethylation at CpG sites in its promoter region in the metastatic tumor tissues compared with the cultured SK-OV-3 cells. We identified crucial cytosine residues at CpG sites in the AGR2 promoter region. Treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine reduced the level of CpG methylation in the AGR2 promoter and increased the level of AGR2 expression. Next, we explored the functional role of AGR2 in the metastatic transformation of SK-OV-3 cells. SK-OV-3 cells overexpressing AGR2 showed increased migratory and invasive activity. Our results indicate that DNA methylation within the AGR2 promoter modulates more aggressive cancer cell phenotypes.

Chanda D, Lee JH, Sawant A, et al.
Anterior gradient protein-2 is a regulator of cellular adhesion in prostate cancer.
PLoS One. 2014; 9(2):e89940 [PubMed] Free Access to Full Article Related Publications
Anterior Gradient Protein (AGR-2) is reported to be over-expressed in many epithelial cancers and promotes metastasis. A clear-cut mechanism for its observed function(s) has not been previously identified. We found significant upregulation of AGR-2 expression in a bone metastatic prostate cancer cell line, PC3, following culturing in bone marrow-conditioned medium. Substantial AGR-2 expression was also confirmed in prostate cancer tissue specimens in patients with bone lesions. By developing stable clones of PC3 cells with varying levels of AGR-2 expression, we identified that abrogation of AGR-2 significantly reduced cellular attachment to fibronectin, collagen I, collagen IV, laminin I and fibrinogen. Loss of cellular adhesion was associated with sharp decrease in the expression of α4, α5, αV, β3 and β4 integrins. Failure to undergo apoptosis following detachment is a hallmark of epithelial cancer metastasis. The AGR-2-silenced PC3 cells showed higher resistance to Tumor necrosis factor-related apoptosis- inducing ligand (TRAIL) induced apoptosis in vitro. This observation was also supported by significantly reduced Caspase-3 expression in AGR-2-silenced PC3 cells, which is a key effector of both extrinsic and intrinsic death signaling pathways. These data suggest that AGR-2 influence prostate cancer metastasis by regulation of cellular adhesion and apoptosis.

Pentheroudakis G, Kotoula V, Fountzilas E, et al.
A study of gene expression markers for predictive significance for bevacizumab benefit in patients with metastatic colon cancer: a translational research study of the Hellenic Cooperative Oncology Group (HeCOG).
BMC Cancer. 2014; 14:111 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Bevacizumab, an antibody neutralizing Vascular Endothelial Growth Factor (VEGF), is licensed for the management of patients with advanced colon cancer. However, tumor biomarkers identifying the molecular tumor subsets most amenable to angiogenesis modulation are lacking.
METHODS: We profiled expession of 24526 genes by means of whole genome 24 K DASL (c-DNA-mediated, Annealing, Selection and Ligation) arrays, (Illumina, CA) in 16 bevacizumab-treated patients with advanced colon cancer (Test set). Genes with correlation to 8-month Progression-free status were studied by means of qPCR in two independent colon cancer cohorts: 49 patients treated with bevacizumab + chemotherapy (Bevacizumab qPCR set) and 72 patients treated with chemotherapy only (Control qPCR set). Endpoints were best tumor response before metastasectomy (ORR) and progression-free survival (PFS).
RESULTS: Five genes were significantly correlated to 8-month progression-free status in the Test set: overexpression of KLF12 and downregulation of AGR2, ALDH6A1, MCM5, TFF2. In the two independent datasets, irinotecan- or oxaliplatin-based chemotherapy was administered as first-line treatment and metastasectomies were subsequently applied in 8-14% of patients. No prognostically significant gene classifier encompassing all five genes could be validated in the Bevacizumab or Control qPCR sets. The complex gene expression profile of all-low tumor (ALDH6A1 + TFF2 + MCM5) was strongly associated with ORR in the Bevacizumab qPCR set (ORR 85.7%, p = 0.007), but not in the Control set (ORR 36.4%, p = 0.747). The Odds Ratio for response for the all-low tumor (ALDH6A1 + TFF2 + MCM5) profile versus any other ALDH6A1 + TFF2 + MCM5 profile was 15 (p = 0.018) in the Bevacizumab qPCR set but only 0.72 (p = 0.63) in the Control set. The tumor expression profile of (KLF12-high + TFF2-low) was significantly associated with PFS only in the Bevacizumab qPCR set: bevacizumab-treated patients with (KLF12-high + TFF2-low) tumors had superior PFS (median 14 months, 95% CI 2-21) compared to patients with any other (KLF12 + TFF2) expression profile (median PFS 7 months, 95% CI 5-10, p = 0.021). The Hazard Ratio for disease progression for (KLF12-high + TFF2-low) versus any other KLF12 + TFF2 expression profile was 2.92 (p = 0.03) in the Validation and 1.29 (p = 0.39) in the Control set.
CONCLUSIONS: Our «three-stage» hypothesis-generating study failed to validate the prognostic significance of a five-gene classifier in mCRC patients. Exploratory analyses suggest two gene signatures that are potentially associated with bevazicumab benefit in patients with advanced colon cancer.

Shishkin SS, Eremina LS, Kovalev LI, Kovaleva MA
AGR2, ERp57/GRP58, and some other human protein disulfide isomerases.
Biochemistry (Mosc). 2013; 78(13):1415-30 [PubMed] Related Publications
This review considers the major features of human proteins AGR2 and ERp57/GRP58 and of other members of the protein disulfide isomerase (PDI) family. The ability of both AGR2 and ERp57/GRP58 to catalyze the formation of disulfide bonds in proteins is the parameter most important for assigning them to a PDI family. Moreover, these proteins and also other members of the PDI family have specific structural features (thioredoxin-like domains, special C-terminal motifs characteristic for proteins localized in the endoplasmic reticulum, etc.) that are necessary for their assignment to a PDI family. Data demonstrating the role of these two proteins in carcinogenesis are analyzed. Special attention is given to data indicating the presence of biomarker features in AGR2 and ERp57/GRP58. It is now thought that there is sufficient reason for studies of AGR2 and ERp57/GRP58 for possible use of these proteins in diagnosis of tumors. There are also prospects for studies on AGR2 and ERp57/GRP58 leading to developments in chemotherapy. Thus, we suppose that further studies on different members of the PDI family using modern postgenomic technologies will broaden current concepts about functions of these proteins, and this will be helpful for solution of urgent biomedical problems.

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