ATP7B

Gene Summary

Gene:ATP7B; ATPase, Cu++ transporting, beta polypeptide
Aliases: WD, PWD, WC1, WND
Location:13q14.3
Summary:This gene is a member of the P-type cation transport ATPase family and encodes a protein with several membrane-spanning domains, an ATPase consensus sequence, a hinge domain, a phosphorylation site, and at least 2 putative copper-binding sites. This protein functions as a monomer, exporting copper out of the cells, such as the efflux of hepatic copper into the bile. Alternate transcriptional splice variants, encoding different isoforms with distinct cellular localizations, have been characterized. Mutations in this gene have been associated with Wilson disease (WD). [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:copper-transporting ATPase 2
HPRD
Source:NCBIAccessed: 26 August, 2015

Ontology:

What does this gene/protein do?
Show (29)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 26 August 2015 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.

  • Chromosome 13
  • Carrier Proteins
  • RTPCR
  • Survival Rate
  • Adenosine Triphosphatases
  • Squamous Cell Carcinoma
  • Single Nucleotide Polymorphism
  • Ceruloplasmin
  • Cell Survival
  • Spectrometry, Mass, Electrospray Ionization
  • Protein Binding
  • Carcinoma
  • Cation Transport Proteins
  • Base Sequence
  • Binding Sites
  • Trans-Activators
  • Chelating Agents
  • Copper
  • ATP-Binding Cassette Transporters
  • Cancer Gene Expression Regulation
  • Xenograft Models
  • Tissue Array Analysis
  • Bladder Cancer
  • Gene Expression
  • Mutation
  • Biological Transport
  • Ovarian Cancer
  • Antineoplastic Agents
  • Messenger RNA
  • Drug Resistance
  • Transfection
  • Immunohistochemistry
  • Homeostasis
  • Tissue Distribution
  • Cisplatin
  • Liver Cancer
  • Membrane Proteins
  • Zinc
  • Metallothionein
Tag cloud generated 26 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

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: ATP7B (cancer-related)

Sun XX, He X, Yin L, et al.
The nucleolar ubiquitin-specific protease USP36 deubiquitinates and stabilizes c-Myc.
Proc Natl Acad Sci U S A. 2015; 112(12):3734-9 [PubMed] Article available free on PMC after 24/09/2015 Related Publications
c-Myc protein stability and activity are tightly regulated by the ubiquitin-proteasome system. Aberrant stabilization of c-Myc contributes to many human cancers. c-Myc is ubiquitinated by SCF(Fbw7) (a SKP1-cullin-1-F-box complex that contains the F-box and WD repeat domain-containing 7, Fbw7, as the F-box protein) and several other ubiquitin ligases, whereas it is deubiquitinated and stabilized by ubiquitin-specific protease (USP) 28. The bulk of c-Myc degradation appears to occur in the nucleolus. However, whether c-Myc is regulated by deubiquitination in the nucleolus is not known. Here, we report that the nucleolar deubiquitinating enzyme USP36 is a novel c-Myc deubiquitinase. USP36 interacts with and deubiquitinates c-Myc in cells and in vitro, leading to the stabilization of c-Myc. This USP36 regulation of c-Myc occurs in the nucleolus. Interestingly, USP36 interacts with the nucleolar Fbw7γ but not the nucleoplasmic Fbw7α. However, it abolished c-Myc degradation mediated both by Fbw7γ and by Fbw7α. Consistently, knockdown of USP36 reduces the levels of c-Myc and suppresses cell proliferation. We further show that USP36 itself is a c-Myc target gene, suggesting that USP36 and c-Myc form a positive feedback regulatory loop. High expression levels of USP36 are found in a subset of human breast and lung cancers. Altogether, these results identified USP36 as a crucial and bono fide deubiquitinating enzyme controlling c-Myc's nucleolar degradation pathway.

Stopa N, Krebs JE, Shechter D
The PRMT5 arginine methyltransferase: many roles in development, cancer and beyond.
Cell Mol Life Sci. 2015; 72(11):2041-59 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
Post-translational arginine methylation is responsible for regulation of many biological processes. The protein arginine methyltransferase 5 (PRMT5, also known as Hsl7, Jbp1, Skb1, Capsuleen, or Dart5) is the major enzyme responsible for mono- and symmetric dimethylation of arginine. An expanding literature demonstrates its critical biological function in a wide range of cellular processes. Histone and other protein methylation by PRMT5 regulate genome organization, transcription, stem cells, primordial germ cells, differentiation, the cell cycle, and spliceosome assembly. Metazoan PRMT5 is found in complex with the WD-repeat protein MEP50 (also known as Wdr77, androgen receptor coactivator p44, or Valois). PRMT5 also directly associates with a range of other protein factors, including pICln, Menin, CoPR5 and RioK1 that may alter its subcellular localization and protein substrate selection. Protein substrate and PRMT5-MEP50 post-translation modifications induce crosstalk to regulate PRMT5 activity. Crystal structures of C. elegans PRMT5 and human and frog PRMT5-MEP50 complexes provide substantial insight into the mechanisms of substrate recognition and procession to dimethylation. Enzymological studies of PRMT5 have uncovered compelling insights essential for future development of specific PRMT5 inhibitors. In addition, newly accumulating evidence implicates PRMT5 and MEP50 expression levels and their methyltransferase activity in cancer tumorigenesis, and, significantly, as markers of poor clinical outcome, marking them as potential oncogenes. Here, we review the substantial new literature on PRMT5 and its partners to highlight the significance of understanding this essential enzyme in health and disease.

Zhou C, Shen L, Mao L, et al.
miR-92a is upregulated in cervical cancer and promotes cell proliferation and invasion by targeting FBXW7.
Biochem Biophys Res Commun. 2015; 458(1):63-9 [PubMed] Related Publications
MicroRNAs (miRNAs) are involved in the cervical carcinogenesis and progression. In this study, we investigated the role of miR-92a in progression and invasion of cervical cancer. MiR-92a was significantly upregulated in cervical cancer tissues and cell lines. Overexpression of miR-92a led to remarkably enhanced proliferation by promoting cell cycle transition from G1 to S phase and significantly enhanced invasion of cervical cancer cells, while its knockdown significantly reversed these cellular events. Bioinformatics analysis suggested F-box and WD repeat domain-containing 7 (FBXW7) as a novel target of miR-92a, and miR-92a suppressed the expression level of FBXW7 mRNA by direct binding to its 3'-untranslated region (3'UTR). Expression of miR-92a was negatively correlated with FBXW7 in cervical cancer tissues. Furthermore, Silencing of FBXW7 counteracted the effects of miR-92a suppression, while its overexpression reversed oncogenic effects of miR-92a. Together, these findings indicate that miR-92a acts as an onco-miRNA and may contribute to the progression and invasion of cervical cancer, suggesting miR-92a as a potential novel diagnostic and therapeutic target of cervical cancer.

Muller KE, Tafe LJ, de Abreu FB, et al.
Benign phyllodes tumor of the breast recurring as a malignant phyllodes tumor and spindle cell metaplastic carcinoma.
Hum Pathol. 2015; 46(2):327-33 [PubMed] Related Publications
We report a unique case of a 59-year-old woman diagnosed with a benign phyllodes tumor (PT), which recurred twice in the same location over a 7-year period: first as a malignant PT and then as a malignant PT with coexisting spindle cell metaplastic breast carcinoma (MBC). The MBC was differentiated from the malignant PT by expression of cytokeratins (CKs) AE1/AE3, CK MNF-116, CK 5/6, and p63. Somatic mutation analysis using a next-generation sequencing platform revealed a shared mutation in F-box and WD repeat domain containing 7, a tumor suppressor gene that encodes a ubiquitin ligase-associated protein, in the original benign PT and the first recurrent malignant PT. Chromosomal microarray analysis showed shared genetic gains and losses between the malignant PT and MBC. This case highlights the utility of immunohistochemistry to differentiate malignant PT from spindle cell MBC, describes a novel mutation in PT, and demonstrates a biologic relationship between these 2 entities.

Li X, Liang W, Liu J, et al.
Transducin (β)-like 1 X-linked receptor 1 promotes proliferation and tumorigenicity in human breast cancer via activation of beta-catenin signaling.
Breast Cancer Res. 2014; 16(5):465 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
INTRODUCTION: Transducin (β)-like 1 X-linked receptor 1(TBLR1) is an F-box-like and WD repeat-containing protein which functions as a switch in transcriptional activation, However, the clinical significance and biological role of TBLR1 in breast cancer remains largely unknown.
METHODS: Western blotting, immunocytochemistry and real-time PCR were used to evaluate TBLR1 expression in normal breast epithelial cells and breast cancer cell lines, clinical tissue samples and adjacent nontumor tissues, and in 214 paraffin-embedded specimens. Statistical analyses were used to test for the prognostic and diagnostic associations. The biological role of TBLR1 -induced proliferation and tumorigenicity in breast cancer cells was explored in vitro and in vivo. The effect of TBLR1 on the expression of cyclin D1 and β-catenin signaling was examined by Western blotting, luciferase reporter assay and by several immunoprecipitation techniques.
RESULTS: TBLR1 was significantly upregulated in breast cancer cells and tissues compared to normal control samples. Immunohistochemical analysis revealed high expression of TBLR1 in 113 of 214 (52.8%) paraffin-embedded archival breast cancer. The overall expression level of TBLR1 was significantly correlated with clinical stage (P <0.001), the tumor classification (P <0.001), node classification (P =0.024), and metastasis classification (P = 0.004), histological grade (P = 0.044), as well as with the expression level of c-erbB2 (P = 0.036) and Ki-67 (P <0.001). Patients with higher TBLR1 expression had shorter overall survival time, whereas patients with lower TBLR1 expression had better survival. Multivariate analysis suggested that TBLR1 expression might be an independent prognostic indicator for the survival of breast cancer patients. TBLR1 overexpression promoted, whereas TBLR1 silencing inhibited, proliferation and tumorigenicity in breast cancer cells both in vitro and in vivo. We found that TBLR1 expression was implicated in the upregulation of cyclin D1, phosphorylation of cell-cycle control protein Rb (pRb) and activation of β-catenin signaling in breast cancer.
CONCLUSIONS: TBLR1 plays a key role in the development and progression of breast cancer cells via cyclin D1-transactivation and activation of the β-catenin signaling pathway. TBLR1 may be a novel prognostic marker and a potential therapeutic target in the treatment human breast cancer.

Chen XM, Xie XB, Zhao Q, et al.
Ampelopsin induces apoptosis by regulating multiple c-Myc/S-phase kinase-associated protein 2/F-box and WD repeat-containing protein 7/histone deacetylase 2 pathways in human lung adenocarcinoma cells.
Mol Med Rep. 2015; 11(1):105-12 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
Ampelopsin (AMP), a plant flavonoid, has been reported to inhibit cell growth and/or induce apoptosis in various types of tumor. The aim of the present study was to assess the apoptosis-inducing activity of AMP in A549 human lung adenocarcinoma epithelial cells and the associated underlying mechanism. A549 cells were incubated with different concentrations of AMP in culture medium. Cell growth and apoptosis were evaluated by MTT assay and Annexin V/propidium iodide double staining and flow cytometry, respectively. In addition, western blotting and reverse transcription quantitative polymerase chain reaction analysis were used to examine the time-dependent changes in protein expression. Certain changes in apoptotic protein expression were detected following exposure to AMP, including X-linked inhibitor of apoptosis protein release, reduced B-cell lymphoma 2, myeloid cell leukemia 1 and survivin expression levels, increased Bcl-2-associated X protein expression levels and cleaved-poly ADP ribose polymerase expression. The results revealed that AMP was a potent inhibitor of A549 cell proliferation. The c-Myc/S-phase kinase-associated protein 2 (Skp2) and histone deacetylase (HDAC)1/2 pathways were found to exert an important role in AMP-induced A549 cell apoptosis, as increased levels of c-Myc mRNA and reduced levels of c-Myc/Skp2 and HDAC1 and 2 proteins following AMP treatment were observed. The levels of F-box and WD repeat-containing protein 7α (Fbw7α), Fbw7β, Fbw7γ, phosphorylated-(p-)c-Myc (Thr58) and glycogen synthase kinase 3β (GSK3β) proteins involved in c-Myc ubiquitin-dependent degradation were also analyzed. Following exposure to AMP, the expression levels of Fbw7α, Fbw7γ and GSK3β were reduced and p-c-Myc (Thr58) expression levels were increased. The results suggest that AMP exerts an anticancer effect, which is associated with the degradation of c-Myc, Skp2 and HDAC1 and 2. The ability of AMP to induce apoptosis independently of Fbwα and Fbw7γ suggests a possible use in drug-resistant cancer associated with Fbw7 deficiency. Understanding the exact underlying mechanism requires further investigation of the association between c-Myc and Fbw7α/γ reversal, and analysis of whether Thr58 phosphorylation of c-Myc is dependent on GSK3β.

Warta R, Theile D, Mogler C, et al.
Association of drug transporter expression with mortality and progression-free survival in stage IV head and neck squamous cell carcinoma.
PLoS One. 2014; 9(9):e108908 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
Drug transporters such as P-glycoprotein (ABCB1) have been associated with chemotherapy resistance and are considered unfavorable prognostic factors for survival of cancer patients. Analyzing mRNA expression levels of a subset of drug transporters by quantitative reverse transcription polymerase chain reaction (qRT-PCR) or protein expression by tissue microarray (TMA) in tumor samples of therapy naïve stage IV head and neck squamous cell carcinoma (HNSCC) (qRT-PCR, n = 40; TMA, n = 61), this in situ study re-examined the significance of transporter expression for progression-free survival (PFS) and overall survival (OS). Data from The Cancer Genome Atlas database was used to externally validate the respective findings (n = 317). In general, HNSCC tended to lower expression of drug transporters compared to normal epithelium. High ABCB1 mRNA tumor expression was associated with both favorable progression-free survival (PFS, p = 0.0357) and overall survival (OS, p = 0.0535). Similar results were obtained for the mRNA of ABCC1 (MRP1, multidrug resistance-associated protein 1; PFS, p = 0.0183; OS, p = 0.038). In contrast, protein expression of ATP7b (copper transporter ATP7b), mRNA expression of ABCG2 (BCRP, breast cancer resistance protein), ABCC2 (MRP2), and SLC31A1 (hCTR1, human copper transporter 1) did not correlate with survival. Cluster analysis however revealed that simultaneous high expression of SLC31A1, ABCC2, and ABCG2 indicates poor survival of HNSCC patients. In conclusion, this study militates against the intuitive dogma where high expression of drug efflux transporters indicates poor survival, but demonstrates that expression of single drug transporters might indicate even improved survival. Prospectively, combined analysis of the 'transportome' should rather be performed as it likely unravels meaningful data on the impact of drug transporters on survival of patients with HNSCC.

Nian X, Zhang W, Li L, et al.
Meta-analysis of studies on the association between the NF-κB1-94ins/del ATTG promoter polymorphism and cancer.
Tumour Biol. 2014; 35(12):11921-31 [PubMed] Related Publications
Nuclear factor-kappa B (NF-κB), a cell survival signal, is involved in carcinogenesis. Polymorphism of NF-κB1 is associated with cancer by several studies. This study aims to perform a comprehensive meta-analysis of studies and determine the association between the NF-κB1-94ins/del ATTG promoter polymorphism and cancer. Twenty-five case-control studies (7,281 cases and 10,039 controls) were included. We used odds ratios (ORs) to assess the strength of the association, and 95 % confidence intervals (CIs) to identify precision of the estimate. Overall, NF-κB1-94ins/del ATTG promoter polymorphism was significantly associated with decreased susceptibility to cancer in overall population under homozygote (for DD vs. WW: OR = 0.74, 95 % CI = 0.58-0.96), recessive (for DD vs. WD+WW: OR = 0.82, 95 % CI = 0.69-0.99), dominant (for DD+WD vs. WW: OR = 0.84, 95 % CI = 0.71-1.00), and allele (for D vs. W: OR = 0.88, 95 % CI = 0.78-0.98) model. Subgroup analysis for ethnicity found that NF-κB1-94ins/del ATTG promoter polymorphism was significantly associated with decreased susceptibility to cancer in Asians (for DD vs. WW: OR = 0.54, 95 % CI = 0.40-0.74; for WD vs. WW: OR = 0.75, 95 % CI = 0.69-0.81; for DD vs. WD+WW: OR = 0.70, 95 % CI = 0.55-0.90; for DD+WD vs. WW; OR = 0.66, 95 % CI = 0.56-0.78; for D vs. W: OR = 0.75, 95 % CI = 0.65-0.86), but the association was not found in Caucasians. The findings suggest that NF-κB1-94ins/delATTG promoter polymorphism is significantly associated with decreased susceptibility to cancer in overall and Asian population.

Eto K, Iwatsuki M, Watanabe M, et al.
The sensitivity of gastric cancer to trastuzumab is regulated by the miR-223/FBXW7 pathway.
Int J Cancer. 2015; 136(7):1537-45 [PubMed] Related Publications
A recent large-scale phase III study (the ToGA trial) demonstrated the significant efficacy of trastuzumab combined with chemotherapy in patients with HER2-positive gastric cancer. Although trastuzumab has become a key drug in cancer treatment, the resistance of breast cancer to trastuzumab is a major problem in clinical practice. However, it is unclear whether similar mechanisms of trastuzumab resistance are involved in gastric cancer (GC). The aim of the current study was to identify a novel micro-RNA (miR)/gene pathway that regulates the sensitivity of HER2-positive GC cells to trastuzumab. We focused on F-box and WD repeat domain-containing 7 (FBXW7), which is one of the major causes of drug resistance. We also identified miR-223, which can regulate FBXW7, using miR quantitative reverse transcription-PCR array analysis using by resistance cell line, which we established. Overexpression of miR-223 decreased FBXW7 expression and the sensitivity of GC cells to trastuzumab, while suppression of miR-223 restored FBXW7 expression and the sensitivity of GC cells to trastuzumab. Moreover, overexpression of miR-223 significantly suppressed trastuzumab-induced apoptosis. This study is the first report to reveal that the miR-223/FBXW7 pathway regulates the sensitivity of a HER2-positive GC cell line to trastuzumab through the modulation of apoptosis. These findings suggest that this pathway can be crucial for the mechanism of trastuzumab resistance in GC, which may lead to the development of individualized treatment in clinical practice.

Spincemaille P, Pham DH, Chandhok G, et al.
The plant decapeptide OSIP108 prevents copper-induced toxicity in various models for Wilson disease.
Toxicol Appl Pharmacol. 2014; 280(2):345-51 [PubMed] Related Publications
BACKGROUND: Wilson disease (WD) is caused by accumulation of excess copper (Cu) due to a mutation in the gene encoding the liver Cu transporter ATP7B, and is characterized by acute liver failure or cirrhosis and neuronal cell death. We investigated the effect of OSIP108, a plant derived decapeptide that prevents Cu-induced apoptosis in yeast and human cells, on Cu-induced toxicity in various mammalian in vitro models relevant for WD and in a Cu-toxicity zebrafish larvae model applicable to WD.
METHODS: The effect of OSIP108 was evaluated on viability of various cell lines in the presence of excess Cu, on liver morphology of a Cu-treated zebrafish larvae strain that expresses a fluorescent reporter in hepatocytes, and on oxidative stress levels in wild type AB zebrafish larvae.
RESULTS: OSIP108 increased not only viability of Cu-treated CHO cells transgenically expressing ATP7B and the common WD-causing mutant ATP7B(H1069Q), but also viability of Cu-treated human glioblastoma U87 cells. Aberrancies in liver morphology of Cu-treated zebrafish larvae were observed, which were further confirmed as Cu-induced hepatotoxicity by liver histology. Injections of OSIP108 into Cu-treated zebrafish larvae significantly increased the amount of larvae with normal liver morphology and decreased Cu-induced production of reactive oxygen species.
CONCLUSIONS: OSIP108 prevents Cu-induced toxicity in in vitro models and in a Cu-toxicity zebrafish larvae model applicable to WD.
GENERAL SIGNIFICANCE: All the above data indicate the potential of OSIP108 as a drug lead for further development as a novel WD treatment.

Brigger D, Proikas-Cezanne T, Tschan MP
WIPI-dependent autophagy during neutrophil differentiation of NB4 acute promyelocytic leukemia cells.
Cell Death Dis. 2014; 5:e1315 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
Members of the WD-repeat protein interacting with phosphoinositides (WIPI) family are phosphatidylinositol 3-phosphate (PI3P) effectors that are essential for the formation of autophagosomes. Autophagosomes, unique double-membraned organelles, are characteristic for autophagy, a bulk degradation mechanism with cytoprotective and homeostatic function. Both, WIPI-1 and WIPI-2 are aberrantly expressed in several solid tumors, linking these genes to carcinogenesis. We now found that the expression of WIPI-1 was significantly reduced in a large cohort of 98 primary acute myeloid leukemia (AML) patient samples (complex karyotypes; t(8;21); t(15,17); inv(16)). In contrast, the expression of WIPI-2 was only reduced in acute promyelocytic leukemia (APL), a distinct subtype of AML (t(15,17)). As AML cells are blocked in their differentiation, we tested if the expression levels of WIPI-1 and WIPI-2 increase during all-trans retinoic acid (ATRA)-induced neutrophil differentiation of APL. According to the higher WIPI-1 expression in granulocytes compared with immature blast cells, WIPI-1 but not WIPI-2 expression was significantly induced during neutrophil differentiation of NB4 APL cells. Interestingly, the induction of WIPI-1 expression was dependent on the transcription factor PU.1, a master regulator of myelopoiesis, supporting our notion that WIPI-1 expression is reduced in AML patients lacking proper PU-1 activity. Further, knocking down WIPI-1 in NB4 cells markedly attenuated the autophagic flux and significantly reduced neutrophil differentiation. This result was also achieved by knocking down WIPI-2, suggesting that both WIPI-1 and WIPI-2 are functionally required and not redundant in mediating the PI3P signal at the onset of autophagy in NB4 cells. In line with these data, downregulation of PI3KC3 (hVPS34), which generates PI3P upstream of WIPIs, also inhibited neutrophil differentiation. In conclusion, we demonstrate that both WIPI-1 and WIPI-2 are required for the PI3P-dependent autophagic activity during neutrophil differentiation, and that PU.1-dependent WIPI-1 expression is significantly repressed in primary AML patient samples and that the induction of autophagic flux is associated with neutrophil differentiation of APL cells.

Wang L, Ye X, Liu Y, et al.
Aberrant regulation of FBW7 in cancer.
Oncotarget. 2014; 5(8):2000-15 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
FBW7 (F-box and WD repeat domain-containing 7) or Fbxw7 is a tumor suppressor, which promotes the ubiquitination and subsequent degradation of numerous oncoproteins including Mcl-1, Cyclin E, Notch, c- Jun, and c-Myc. In turn, FBW7 is regulated by multiple upstream factors including p53, C/EBP-δ, EBP2, Pin1, Hes-5 and Numb4 as well as by microRNAs such as miR-223, miR-27a, miR-25, and miR-129-5p. Given that the Fbw7 tumor suppressor is frequently inactivated or deleted in various human cancers, targeting FBW7 regulators is a promising anti-cancer therapeutic strategy.

Chandhok G, Schmitt N, Sauer V, et al.
The effect of zinc and D-penicillamine in a stable human hepatoma ATP7B knockout cell line.
PLoS One. 2014; 9(6):e98809 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
Mutations in the copper (Cu) transporter gene ATP7B, the primary cause of Wilson disease (WD), result in high liver Cu and death of hepatocytes. Cu chelators and zinc salts are the two most important drugs used in the treatment of WD patients; however, the molecular mechanisms of the drugs with regard to ATP7B expression have not been determined. A targeted knockout of ATP7B (KO) was established in the most widely used human hepatoma cell line, HepG2 for molecular studies of the pathogenesis and treatment of the disease. KO cells showed similar growth, Cu uptake, release, and gene expression as compared to parental cells. However, in the presence of Cu, morphological changes, oxidative stress, apoptosis, and loss of viability were observed. Induction of metallothionein (MT1X) after Cu exposure was significantly reduced in KO cells. Following zinc treatment, MT1X expression was strongly induced and a high percentage of KO cells could be rescued from Cu induced toxicity. D-penicillamine treatment had a minor effect on the viability of KO cells whereas the parental cell line showed a pronounced improvement. Combined treatment displayed a highly synergistic effect in KO cells. The data suggest that zinc has a previously unrecognized effect on the viability of hepatocytes that lack ATP7B due to a high induction of MT1X expression that compensates low gene expression after Cu exposure. A combination therapy that simultaneously targets at MT1X induction and Cu chelation improves the overall survival of hepatocytes for most efficient therapy of patients having WD.

Li XP, Yin JY, Wang Y, et al.
The ATP7B genetic polymorphisms predict clinical outcome to platinum-based chemotherapy in lung cancer patients.
Tumour Biol. 2014; 35(8):8259-65 [PubMed] Related Publications
This study aims to investigate the influence of ATP7B genetic polymorphism to platinum-based chemotherapy in Chinese Han lung cancer patients. A total of 338 Chinese Han lung cancer patients were enrolled in this study. All patients underwent at least two cycles of platinum-based chemotherapy. Four tag SNPs of ATP7B (rs1061472, rs9535826, rs7999812, and rs9535828) were selected to evaluate their impacts to platinum-based chemotherapy in these patients. ATP7B rs9535828 and rs9535826 were found to be associated with platinum resistance in Chinese Han lung cancer patients. Patients with A allele in ATP7B rs9535828 presented an increased susceptibility to platinum drugs (OR 1.96, 95 % CI 1.17-3.30, p < 0.01). Patients with G allele in ATP7B rs9535826 had the highest susceptibility to platinum drugs (OR 2.05, 95 % CI 1.19-3.52, p < 0.01). Our findings suggest that ATP7B genetic polymorphisms could affect the therapeutic efficacy of platinum-based chemotherapy, and ATP7B gene might be considered as predictive markers for the efficacy evaluation of platinum-based chemotherapy in Chinese Han lung cancer patients.

Johnson J, Shi Z, Liu Y, Stack MS
Inhibitors of NF-kappaB reverse cellular invasion and target gene upregulation in an experimental model of aggressive oral squamous cell carcinoma.
Oral Oncol. 2014; 50(5):468-77 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
BACKGROUND: Oral squamous cell carcinoma (OSCC) is diagnosed in 640,000 patients yearly with a poor (50%) 5-year survival rate that has not changed appreciably in decades.
PAITENTS AND METHODS: To investigate molecular changes that drive OSCC progression, cDNA microarray analysis was performed using human OSCC cells that form aggressive poorly differentiated tumors (SCC25-PD) in a murine orthotopic xenograft model compared to cells that produce well-differentiated tumors (SCC25-WD).
RESULTS: As this analysis revealed that 59 upregulated genes were NF-κB target genes, the role of NF-κB activation in alteration of the transcriptional profile was evaluated. The mRNA and protein upregulation of a panel NF-κB target genes was validated by real-time qPCR and immunohistochemistry. Additionally, nuclear translocation of RelA was greatly increased in SCC25-PD, increased nuclear RelA was observed in oral tumors initiated with SCC25-PD compared with tumors initiated by SCC25-WD, and nuclear RelA correlated with stage of disease on two human OSCC tissue microarrays. Treatment of SCC25-PD cells with the IKKβ-inhibitor sc-514, that effectively prevents RelA phosphorylation on Ser 536, reversed nuclear-translocation of RelA and strongly inhibited NF-κB gene activation. Furthermore, blocking the phosphorylation of RelA using the MSK1/2 inhibitor SB 747651A significantly reduced the mRNA upregulation of a subset of target genes. Treatment with sc-514 or SB747651A markedly diminished cellular invasiveness.
CONCLUSIONS: These studies support a model wherein NF-κB is constitutively active in aggressive OSCC, while blocking the NF-κB pathway reduces NF-κB target gene upregulation and cellular invasiveness.

Huang CP, Fofana M, Chan J, et al.
Copper transporter 2 regulates intracellular copper and sensitivity to cisplatin.
Metallomics. 2014; 6(3):654-61 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
Mammalian cells express two copper (Cu) influx transporters, CTR1 and CTR2. CTR1 serves as an influx transporter for both Cu and cisplatin (cDDP). In mouse embryo fibroblasts, reduction of CTR1 expression renders cells resistant to cDDP whereas reduction of CTR2 makes them hypersensitive both in vitro and in vivo. To investigate the role of CTR2 on intracellular Cu and cDDP sensitivity its expression was molecularly altered in the human epithelial 2008 cancer cell model. Intracellular exchangeable Cu(+) was measured with the fluorescent probe Coppersensor-3 (CS3). The ability of CS3 to report on changes in intracellular Cu(+) was validated by showing that Cu chelators reduced its signal, and that changes in signal accompanied alterations in expression of the major Cu influx transporter CTR1 and the two Cu efflux transporters, ATP7A and ATP7B. Constitutive knock down of CTR2 mRNA by ∼50% reduced steady-state exchangeable Cu by 22-23% and increased the sensitivity of 2008 cells by a factor of 2.6-2.9 in two separate clones. Over-expression of CTR2 increased exchangeable Cu(+) by 150% and rendered the 2008 cells 2.5-fold resistant to cDDP. The results provide evidence that CS3 can quantitatively assess changes in exchangeable Cu(+), and that CTR2 regulates both the level of exchangeable Cu(+) and sensitivity to cDDP in a model of human epithelial cancer. This study introduces CS3 and related sensors as novel tools for probing and assaying Cu-dependent sensitivity to anticancer therapeutics.

Kimura N, Takayanagi R, Takizawa N, et al.
Pathological grading for predicting metastasis in phaeochromocytoma and paraganglioma.
Endocr Relat Cancer. 2014; 21(3):405-14 [PubMed] Related Publications
Phaeochromocytomas (PHEO) and paragangliomas are rare catecholamine-producing tumours. Although 10-30% of these tumours metastasise, histopathological criteria to discriminate malignant from benign tumours have not been established; therefore, reliable histopathological markers predicting metastasis are urgently required. A total of 163 tumours, including 40 metastatic tumours, collected by the Phaeochromocytoma Study Group in Japan (PHEO-J) were analysed using a system called grading system for adrenal phaeochromocytoma and paraganglioma (GAPP). The tumours were scored based on GAPP criteria as follows: histological pattern, cellularity, comedo-type necrosis, capsular/vascular invasion, Ki67 labelling index and catecholamine type. All tumours were scored from 0 to 10 points and were graded as one of the three types: well-differentiated (WD, 0-2 points), moderately differentiated (MD, 3-6 points) and poorly differentiated (PD, 7-10 points). GAPP scores of the non-metastatic and metastatic groups were 2.08±0.17 and 5.33±0.43 (mean±s.e.m., P<0.001) respectively. There was a significant negative correlation between the GAPP score and the interval until metastasis (r=-0.438, P<0.01). The mean number of years until metastasis after the initial operation was 5.5±2.6 years. The study included 111 WD, 35 MD and 17 PD types. The five-year survival of these groups was 100, 66.8 and 22.4% respectively. In addition, negative immunoreactivity for succinate dehydrogenase gene subunit B (SDHB) was observed in 13 (8%) MD or PD tumours and ten of the 13 (77%) had metastases. Our data indicate that a combination of GAPP classification and SDHB immunohistochemistry might be useful for the prediction of metastasis in these tumours.

Liao P, Wang W, Shen M, et al.
A positive feedback loop between EBP2 and c-Myc regulates rDNA transcription, cell proliferation, and tumorigenesis.
Cell Death Dis. 2014; 5:e1032 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
The oncoprotein c-Myc is a key transcription factor with essential functions in the nucleolus (NO) to regulate ribosomal RNA (rRNA) synthesis, ribosome biogenesis, and cell proliferation. Yet, the mechanism that regulates the distribution and function of nucleolar c-Myc is still not completely understood. In this study, we identified nucleolar protein ENBA1 binding protein 2 (EBP2) as a novel functional binding partner of c-Myc. We found that coexpression of EBP2 markedly relocalized c-Myc from the nucleus to the NO, whereas depletion of EBP2 reduced the nucleolar distribution of c-Myc. Further study indicated that EBP2 is a direct binding partner of c-Myc and can block the degradation of c-Myc in a FBW7 (F-box and WD repeat domain containing 7)-independent manner. Moreover, EBP2 is a transcriptional target of c-Myc. c-Myc can bind to the promoter of EBP2 and positively regulate the EBP2 expression. Both protein and mRNA levels of EBP2 are upregulated in lung cancer samples and positively correlated with c-Myc expression. Functionally, EBP2 promotes c-Myc-mediated rRNA synthesis and cell proliferation. Collectively, our study indicates that EBP2 is a novel binding partner of c-Myc that regulates the function of nucleolar c-Myc, cell proliferation, and tumorigenesis via a positive feedback loop.

Ciarimboli G
Membrane transporters as mediators of cisplatin side-effects.
Anticancer Res. 2014; 34(1):547-50 [PubMed] Related Publications
The clinical use of the efficient chemotherapeutic drug cisplatin is limited by its specific severe organ toxicities such as nephro-, oto-, and also peripheral neurotoxicity. Membrane transporters such as the copper transporter-1 (Ctr1), the copper transporter-2 (Ctr2), the P-type copper-transporting ATPases ATP7A and ATP7B, the organic cation transporter-2 (OCT2), and the multidrug extrusion transporter-1 (MATE1) mediate cellular transport of cisplatin. Since OCT2 is specifically expressed in the kidneys, its role as possible target of specific organ protection against undesired cisplatin toxicity is under investigation. We could show that OCT2 is also expressed in the cochlea in hair cells and in cells of the stria vascularis and also in dorsal root ganglia of mice. Moreover, we could show in a mouse model of cisplatin acute toxicities that the expression of OCT is critical for the development of ototoxicity, peripheral neurotoxicity and nephrotoxicity. Competition of cisplatin transport by the OCT2 substrate cimetidine was able to suppress ototoxicity, and reduce nephrotoxicity. Only few human tumors express OCT2, its expression being apparently down-regulated by epigenetic modifications, suggesting that a protective therapy by competition for the transport of cisplatin by OCT2 may be generally feasible without affecting its antitumor potency. There is already some evidence that patients bearing a mutation in OCT2 gene or co-medicated with cimetidine are protected against cisplatin nephrotoxicity. In conclusion, OCT2 seems to be an ideal target for the establishment of protective therapies aimed to specifically reduce cisplatin side-effects and increase the quality of life of the patients.

Doherty B, Lawlor D, Gillet JP, et al.
Collateral sensitivity to cisplatin in KB-8-5-11 drug-resistant cancer cells.
Anticancer Res. 2014; 34(1):503-7 [PubMed] Related Publications
BACKGROUND: KB-8-5-11 cells are a drug-resistant cervical cell model that overexpresses ABCB1 (P-glycoprotein). KB-8-5-11 has become sensitive to non-ABCB1 substrate cisplatin. Understanding the mechanism of collateral sensitivity to cisplatin may lead to biomarker discovery for platinum sensitivity in patients with cancer.
MATERIALS AND METHODS: A Taqman low-density array was used to characterize the expression of 380 genes previously associated with chemoresistance. Identified pathways were further analyzed using cytotoxicity assays, metabolomics and western blots.
RESULTS: KB-8-5-11 cells were sensitive to CuSO4 and the glutathione inhibitor buthionine sulphoximine. Expression of ATPase, Cu(2+) transporting alpha (ATP7A) and ATP7B were decreased at the protein and gene levels respectively in KB-8-5-11. KB-8-5-11 had decreased gene expression of glutathione S-transferase pi 1 (GSTP1), GSTA4 and GSTK1. Cisplatin treatment significantly lowered total cellular glutathione in parental KB-3-1 cells. Glutathione also tended to be lower in KB-8-5-11 cells compared to KB-3-1 cells.
CONCLUSION: KB-8-5-11 cells have alterations in their copper transporters and glutathione metabolism, contributing to their cisplatin-sensitive phenotype.

Wang H, Chen Y, Lin P, et al.
The CUL7/F-box and WD repeat domain containing 8 (CUL7/Fbxw8) ubiquitin ligase promotes degradation of hematopoietic progenitor kinase 1.
J Biol Chem. 2014; 289(7):4009-17 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
HPK1, a member of mammalian Ste20-like serine/threonine kinases, is lost in >95% pancreatic cancer through proteasome-mediated degradation. However, the mechanism of HPK1 loss has not been defined. The aims of this study are to identify the ubiquitin ligase and to examine the mechanisms that targets HPK1 degradation. We found that the CUL7/Fbxw8 ubiquitin ligase targeted HPK1 for degradation via the 26 S proteasome. The ubiquitination of HPK1 required its kinase activity and autophosphorylation. Wild-type protein phosphatase 4 (PP4), but not the phosphatase-dead PP4 mutant, PP4-RL, inhibits the interaction of Fbxw8 with HPK1 and Fbxw8-mediated ubiquitination of HPK1. In addition, we showed that Thr-355 of HPK1 is a key PP4 dephosphorylation site, through which CUL7/Fbxw8 ubiquitin ligase and PP4 regulates HPK1 stability. Knockdown of Fbxw8 restores endogenous HPK1 protein expression and inhibits cell proliferation of pancreatic cancer cells. Our study demonstrated that targeted degradation of HPK1 by the CUL7/Fbxw8 ubiquitin ligase constitutes a negative-feedback loop to restrain the activity of HPK1 and that CUL7/Fbxw8 ubiquitin ligase promotes pancreatic cancer cell proliferation. CUL7/Fbxw8 ubiquitin ligase-mediated HPK1 degradation revealed a direct link and novel role of CUL7/Fbxw8 ubiquitin ligase in the MAPK pathway, which plays a critical role in cell proliferation and differentiation.

Xie C, Powell C, Yao M, et al.
Ubiquitin-conjugating enzyme E2C: a potential cancer biomarker.
Int J Biochem Cell Biol. 2014; 47:113-7 [PubMed] Related Publications
The ubiquitin-conjugating enzymes 2C (UBE2C) is an integral component of the ubiquitin proteasome system. UBE2C consists of a conserved core domain containing the catalytic Cys residue and an N-terminal extension. The core domain is required for ubiquitin adduct formation by interacting with the ubiquitin-fold domain in the E1 enzyme, and contributes to the E3 enzyme binding. UBE2C N-terminal extension regulates E3 enzyme activity as a part of an intrinsic inhibitory mechanism. UBE2C is required for the destruction of mitotic cyclins and securin, which are essential for spindle assembly checkpoint and mitotic exit. The UBE2C mRNA and/or protein levels are aberrantly increased in many cancer types with poor clinical outcomes. Accumulation of UBE2C stimulates cell proliferation and anchorage-independent growth. UBE2C transgenic mice are prone to develop spontaneous tumors and carcinogen-induced tumor with evidence of chromosome aneuploidy.

Nakano K, Miki Y, Hata S, et al.
Identification of androgen-responsive microRNAs and androgen-related genes in breast cancer.
Anticancer Res. 2013; 33(11):4811-9 [PubMed] Related Publications
BACKGROUND: Androgen receptors (ARs) are expressed in many breast cancer cells, but the mechanism of action of androgens is not as well-characterized as in other cell types. The study of microRNAs has recently provided with important insights into the biology of hormone-dependent cancer.
MATERIALS AND METHODS: We attempted to identify microRNAs induced by dihydrotestosterone in an AR-positive cell line. We examined a possible correlation among microRNAs, target genes, and ARs in breast cancer tissues using immunohistochemistry and laser capture microscopy.
RESULTS: Our analysis demonstrated that miR-363 and its possible target IQ motif and WD repeats-1 (IQWD1) are involved in a microRNA-mRNA pathway related to the mechanism of action of androgens. Our analyses showed that a high tumor level of IQWD1 in patients with breast cancer was significantly associated with adverse clinical outcomes.
CONCLUSION: Our findings indicated that the recruitment of IQWD1 to ARs may be a prerequisite for the growth stimulation by androgens through ARs in breast cancer cells.

Pussila M, Sarantaus L, Dermadi Bebek D, et al.
Cancer-predicting gene expression changes in colonic mucosa of Western diet fed Mlh1+/- mice.
PLoS One. 2013; 8(10):e76865 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
Colorectal cancer (CRC) is the second most common cause of cancer-related deaths in the Western world and interactions between genetic and environmental factors, including diet, are suggested to play a critical role in its etiology. We conducted a long-term feeding experiment in the mouse to address gene expression and methylation changes arising in histologically normal colonic mucosa as putative cancer-predisposing events available for early detection. The expression of 94 growth-regulatory genes previously linked to human CRC was studied at two time points (5 weeks and 12 months of age) in the heterozygote Mlh1(+/-) mice, an animal model for human Lynch syndrome (LS), and wild type Mlh1(+/+) littermates, fed by either Western-style (WD) or AIN-93G control diet. In mice fed with WD, proximal colon mucosa, the predominant site of cancer formation in LS, exhibited a significant expression decrease in tumor suppressor genes, Dkk1, Hoxd1, Slc5a8, and Socs1, the latter two only in the Mlh1(+/-) mice. Reduced mRNA expression was accompanied by increased promoter methylation of the respective genes. The strongest expression decrease (7.3 fold) together with a significant increase in its promoter methylation was seen in Dkk1, an antagonist of the canonical Wnt signaling pathway. Furthermore, the inactivation of Dkk1 seems to predispose to neoplasias in the proximal colon. This and the fact that Mlh1 which showed only modest methylation was still expressed in both Mlh1(+/-) and Mlh1(+/+) mice indicate that the expression decreases and the inactivation of Dkk1 in particular is a prominent early marker for colon oncogenesis.

Gangula NR, Maddika S
WD repeat protein WDR48 in complex with deubiquitinase USP12 suppresses Akt-dependent cell survival signaling by stabilizing PH domain leucine-rich repeat protein phosphatase 1 (PHLPP1).
J Biol Chem. 2013; 288(48):34545-54 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
PHLPP1 (PH domain leucine-rich repeat protein phosphatase 1) is a protein-serine/threonine phosphatase and a negative regulator of the PI3-kinase/Akt pathway. Although its function as a suppressor of tumor cell growth has been established, the mechanism of its regulation is not completely understood. In this study, by utilizing the tandem affinity purification approach we have identified WDR48 and USP12 as novel PHLPP1-associated proteins. The WDR48·USP12 complex deubiquitinates PHLPP1 and thereby enhances its protein stability. Similar to PHLPP1 function, WDR48 and USP12 negatively regulate Akt activation and thus promote cellular apoptosis. Functionally, we show that WDR48 and USP12 suppress proliferation of tumor cells. Importantly, we found a WDR48 somatic mutation (L580F) that is defective in stabilizing PHLPP1 in colorectal cancers, supporting a WDR48 role in tumor suppression. Together, our results reveal WDR48 and USP12 as novel PHLPP1 regulators and potential suppressors of tumor cell survival.

Mungamuri SK, Murk W, Grumolato L, et al.
Chromatin modifications sequentially enhance ErbB2 expression in ErbB2-positive breast cancers.
Cell Rep. 2013; 5(2):302-13 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
ErbB2 gene amplification occurs in 20%-25% of breast cancers, and its therapeutic targeting has markedly improved survival of patients with breast cancer in the adjuvant setting. However, resistance to these therapies can develop. Because epigenetic mechanisms can importantly influence oncogene expression and be druggable as well, we investigated histone modifications that influence ErbB2 overexpression, independent of gene amplification. We demonstrate here that ErbB2-overexpressing breast carcinomas acquire the H3K4me3 mark on the erbB2 promoter and that receptor-amplified tumors further acquire the H3K9ac mark, which is dependent on H3K4me3 mark acquisition. Targeting WD repeat domain 5 (Wdr5), which is absolutely required for H3K4me3 enrichment, decreased ErbB2 overexpression, associated with a decrease in the H3K4me3 mark on the erbB2 promoter. Of note, Wdr5 silencing cooperated with trastuzumab or chemotherapy in specifically inhibiting the growth of ErbB2-positive breast tumor cells. Thus, our studies illuminate epigenetic steps in the selection for ErbB2 activation.

Karachaliou N, Papadaki C, Lagoudaki E, et al.
Predictive value of BRCA1, ERCC1, ATP7B, PKM2, TOPOI, TOPΟ-IIA, TOPOIIB and C-MYC genes in patients with small cell lung cancer (SCLC) who received first line therapy with cisplatin and etoposide.
PLoS One. 2013; 8(9):e74611 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
BACKGROUND: The aim of the study was to evaluate the predictive value of genes involved in the action of cisplatin-etoposide in Small Cell Lung Cancer (SCLC).
METHODS: 184 SCLC patients' primary tumour samples were analyzed for ERCCI, BRCA1, ATP7B, PKM2 TOPOI, TOPOIIA, TOPOIIB and C-MYC mRNA expression. All patients were treated with cisplatin-etoposide.
RESULTS: The patients' median age was 63 years and 120 (65%) had extended stage, 75 (41%) had increased LDH serum levels and 131 (71%) an ECOG performance status was 0-1. Patients with limited stage, whose tumours expressed high ERCC1 (p=0.028), PKM2 (p=0.046), TOPOI (p=0.008), TOPOIIA (p=0.002) and TOPOIIB (p<0.001) mRNA had a shorter Progression Free Survival (PFS). In limited stage patients, high expression of ERCC1 (p=0.014), PKM2 (p=0.026), TOPOIIA (p=0.021) and TOPOIIB (p=0.019) was correlated with decreased median overall survival (mOS) while in patients with extended stage, only high TOPOIIB expression had a negative impact on Os (p=0.035). The favorable expression signature expression signature (low expression of ERCC1, PKM2, TOPOIIA and TOPOIIB) was correlated with significantly better PFS and Os in both LS-SCLC (p<0.001 and p=0.007, respectively) and ES-SCLC (p=0.007 and (p=0.011, respectively) group. The unfavorable expression signature was an independent predictor for poor PFS (HR: 3.18; p=0.002 and HR: 3.14; p=0.021) and Os (HR: 4.35; p=0.001and HR: 3.32; p=0.019) in both limited and extended stage, respectively.
CONCLUSIONS: Single gene's expression analysis as well as the integrated analysis of ERCC1, PKM2, TOPOIIA and TOPOIIB may predict treatment outcome in patients with SCLC. These findings should be further validated in a prospective study.

Schmid SC, Schuster T, Horn T, et al.
Utility of ATP7B in prediction of response to platinum-based chemotherapy in urothelial bladder cancer.
Anticancer Res. 2013; 33(9):3731-7 [PubMed] Related Publications
BACKGROUND: Platinum-based chemotherapy is the treatment of choice for metastatic urothelial carcinoma, which is limited by primary and secondary resistance of the tumour. The Cu(2+) transporting beta polypeptide ATPase (ATP7B) is believed to play a role in this resistance. The aim of this study was to screen the ATP7B gene for mutations and loss of heterozygosity in bladder cancer and to evaluate their impact on chemotherapy resistance.
MATERIALS AND METHODS: DNA extracted from 17 patients with metastatic bladder cancer was analyzed by DNA sequencing, and microsatellite analysis.
RESULTS: We found 12 non-synonymous mutations and 20 synonymous mutations out of which 11 and 15, respectively, have not been previously described. Results were correlated with response to platinum-based chemotherapy: 65% of patients exhibited LOH of the ATP7B locus on chromosome 13q14.3, with a tendency to have a better response to chemotherapy.
CONCLUSION: Although resistance is complex, LOH at the ATP7B locus might be useful in predicting chemotherapy response and needs further evaluation.

Sakai NS, Samia-Aly E, Barbera M, Fitzgerald RC
A review of the current understanding and clinical utility of miRNAs in esophageal cancer.
Semin Cancer Biol. 2013; 23(6 Pt B):512-21 [PubMed] Related Publications
BACKGROUND: MicroRNAs (miRNAs) are a class of small, well-conserved, non-coding RNAs that regulate the translation of RNAs. They have a role in biological and pathological process including cell differentiation, apoptosis, proliferation and metabolism. Since their discovery, they have been shown to have a potential role in cancer pathogenesis through their function as oncogenes or tumor suppressors. A substantial number of miRNAs show differential expression in esophageal cancer tissues, and so have been investigated for possible use in diagnosis. Furthermore, there is increasing interest in their use as prognostic markers and determining treatment response, as well as identifying their downstream targets and understanding their mode of action.
METHODS: We analyzed the most recent studies on miRNAs in esophageal cancer and/or Barrett's esophagus (BE). The publications were identified by searching in PuBMed for the following terms: Barrett's esophagus and microRNA; esophageal cancer and microRNA.
RESULTS: Four miRNAs (mi-R-25, -99a, -133a and -133b) showed good potential as diagnostic markers and interestingly five (mi-R-21, -27b, -126, - 143 and -145) appeared to be useful both as diagnostic and prognostic/predictive markers.
CONCLUSION: The data so far on miRNAs in esophageal carcinogenesis is promising but further work is required to determine whether miRNAs can be used as biomarkers, not only in the clinical setting or added to individualized treatment regimes but also in non-invasive test by making use of miRNAs identified in blood.

Saeki M, Egusa H, Kamano Y, et al.
Exosome-bound WD repeat protein Monad inhibits breast cancer cell invasion by degrading amphiregulin mRNA.
PLoS One. 2013; 8(7):e67326 [PubMed] Article available free on PMC after 01/06/2016 Related Publications
Increased stabilization of mRNA coding for key cancer genes can contribute to invasiveness. This is achieved by down-regulation of exosome cofactors, which bind to 3'-UTR in cancer-related genes. Here, we identified amphiregulin, an EGFR ligand, as a target of WD repeat protein Monad, a component of R2TP/prefoldin-like complex, in MDA-MB-231 breast cancer cells. Monad specifically interacted with both the 3'-UTR of amphiregulin mRNA and the RNA degrading exosome, and enhanced decay of amphiregulin transcripts. Knockdown of Monad increased invasion and this effect was abolished with anti-amphiregulin neutralizing antibody. These results suggest that Monad could prevent amphiregulin-mediated invasion by degrading amphiregulin mRNA.

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