Gene Summary

Gene:MAP3K8; mitogen-activated protein kinase kinase kinase 8
Aliases: COT, EST, ESTF, TPL2, AURA2, MEKK8, Tpl-2, c-COT
Summary:This gene is an oncogene that encodes a member of the serine/threonine protein kinase family. The encoded protein localizes to the cytoplasm and can activate both the MAP kinase and JNK kinase pathways. This protein was shown to activate IkappaB kinases, and thus induce the nuclear production of NF-kappaB. This protein was also found to promote the production of TNF-alpha and IL-2 during T lymphocyte activation. This gene may also utilize a downstream in-frame translation start codon, and thus produce an isoform containing a shorter N-terminus. The shorter isoform has been shown to display weaker transforming activity. Alternate splicing results in multiple transcript variants that encode the same protein. [provided by RefSeq, Sep 2011]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:mitogen-activated protein kinase kinase kinase 8
Source:NCBIAccessed: 06 August, 2015


What does this gene/protein do?
Show (12)
Pathways:What pathways are this gene/protein implicaed in?
Show (3)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 06 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.

  • TNF
  • Breast Cancer
  • RT-PCR
  • Indoles
  • Cell Movement
  • Thyroid Cancer
  • ras Proteins
  • Cell Proliferation
  • Cell Line
  • Neoplasm Recurrence, Local
  • MicroRNAs
  • Base Sequence
  • Extracellular Signal-Regulated MAP Kinases
  • Chromosome 10
  • Oligonucleotide Array Sequence Analysis
  • Enzyme Activation
  • Mitogen-Activated Protein Kinases
  • MAP Kinase Signaling System
  • Transcription Factor AP-1
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins
  • DNA Methylation
  • Lung Cancer
  • siRNA
  • Gene Expression
  • Polymerase Chain Reaction
  • Gene Amplification
  • Neoplastic Cell Transformation
  • CRAF
  • Sulfonamides
  • Cancer Gene Expression Regulation
  • Messenger RNA
  • MAP Kinase Kinase Kinases
  • Adolescents
  • Melanoma
  • BRAF
  • Telomere
  • Neoplasm Invasiveness
  • Gene Expression Profiling
  • Neoplasm Metastasis
  • Signal Transduction
  • Colorectal Cancer
Tag cloud generated 06 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

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: MAP3K8 (cancer-related)

Ren X, Wu X, Hillier SG, et al.
Local estrogen metabolism in epithelial ovarian cancer suggests novel targets for therapy.
J Steroid Biochem Mol Biol. 2015; 150:54-63 [PubMed] Free Access to Full Article Related Publications
Epithelial ovarian cancer (EOC) accounts for about 90% of malignant ovarian tumors, and estrogen is often implicated in disease progression. We therefore compared the potential for gating of estrogen action via pre-receptor metabolism in normal human ovarian surface epithelium (OSE), EOC and selected EOC cell lines (SKOV3 and PEO1). Steroid sulphatase (STS), estrogen sulfotransferase (EST), 17β-hydroxysteroid dehydrogenases 2 (17BHSD2) and 5 (17BHSD5) mRNAs, proteins and enzymatic activities were all detectable in primary cell cultures of OSE and EOC, whereas aromatase and 17BHSD1 expression was negligible. qRT-PCR assay on total mRNA revealed significantly higher EST mRNA expression in OSE compared to EOC (P<0.05). Radioenzymatic measurements confirmed reduced sulfoconjugation (neutralization) of free estrogen in EOC relative to OSE. OSE cells were more effective at converting free [(3)H]-E1 to [(3)H]-E1S or [(3)H]-E2S, while EOC cell lines mainly converted [(3)H]-E1 to [(3)H]-E2 with minimal formation of [(3)H]-E1S or [(3)H]-E2S. IL1α treatment suppressed EST (P<0.01) and 17BHSD2 (P<0.001) mRNA levels in OSE and stimulated STS mRNA levels (P<0.001) in cancer (SKOV3) cells. These results show that estrogen is differentially metabolized in OSE and EOC cells, with E2 'activation' from conjugated estrogen predominating in EOC. Inflammatory cytokines may further augment the local production of E2 by stimulating STS and suppressing EST. We conclude that local estrogen metabolism may be a target for EOC treatment.

van Roosmalen W, Le Dévédec SE, Golani O, et al.
Tumor cell migration screen identifies SRPK1 as breast cancer metastasis determinant.
J Clin Invest. 2015; 125(4):1648-64 [PubMed] Free Access to Full Article Related Publications
Tumor cell migration is a key process for cancer cell dissemination and metastasis that is controlled by signal-mediated cytoskeletal and cell matrix adhesion remodeling. Using a phagokinetic track assay with migratory H1299 cells, we performed an siRNA screen of almost 1,500 genes encoding kinases/phosphatases and adhesome- and migration-related proteins to identify genes that affect tumor cell migration speed and persistence. Thirty candidate genes that altered cell migration were validated in live tumor cell migration assays. Eight were associated with metastasis-free survival in breast cancer patients, with integrin β3-binding protein (ITGB3BP), MAP3K8, NIMA-related kinase (NEK2), and SHC-transforming protein 1 (SHC1) being the most predictive. Examination of genes that modulate migration indicated that SRPK1, encoding the splicing factor kinase SRSF protein kinase 1, is relevant to breast cancer outcomes, as it was highly expressed in basal breast cancer. Furthermore, high SRPK1 expression correlated with poor breast cancer disease outcome and preferential metastasis to the lungs and brain. In 2 independent murine models of breast tumor metastasis, stable shRNA-based SRPK1 knockdown suppressed metastasis to distant organs, including lung, liver, and spleen, and inhibited focal adhesion reorganization. Our study provides comprehensive information on the molecular determinants of tumor cell migration and suggests that SRPK1 has potential as a drug target for limiting breast cancer metastasis.

Amé-Thomas P, Hoeller S, Artchounin C, et al.
CD10 delineates a subset of human IL-4 producing follicular helper T cells involved in the survival of follicular lymphoma B cells.
Blood. 2015; 125(15):2381-5 [PubMed] Free Access to Full Article Related Publications
In follicular lymphoma (FL), follicular helper T cells (TFH) have been depicted as one of the main components of the malignant B-cell niche and a promising therapeutic target. Although defined by their capacity to sustain FL B-cell growth together with specific gene expression and cytokine secretion profiles, FL-TFH constitute a heterogeneous cell population. However, specific markers reflecting such functional heterogeneity are still lacking. In this study, we demonstrate that CD10 identifies a subset of fully functional germinal center TFH in normal secondary lymphoid organs. Importantly, this subset is amplified in the FL context, unlike in other B-cell lymphomas with a follicular growth pattern. Furthermore, whereas FL-TFH produce high levels of interleukin (IL)-21 and low levels of IL-17 irrespectively of their CD10 expression, CD10(pos) FL-TFH specifically exhibit an IL-4(hi)IFN-γ(lo)TNF-α(hi) cytokine profile associated with a high capacity to sustain directly and indirectly malignant B-cell survival. Altogether, our results highlight the important role of this novel functional subset in the FL cell niche.

Lee J, Jeong S, Park JH, et al.
Aberrant expression of COT is related to recurrence of papillary thyroid cancer.
Medicine (Baltimore). 2015; 94(6):e548 [PubMed] Related Publications
Aberrant expression of Cancer Osaka Thyroid Oncogene mitogen-activated protein kinase kinase kinase 8 (COT) (MAP3K8) is a driver of resistance to B-RAF inhibition. However, the de novo expression and clinical implications of COT in papillary thyroid cancer (PTC) have not been investigated.The aim of this study is to investigate the expression of A-, B-, C-RAF, and COT in PTC (n = 167) and analyze the clinical implications of aberrant expression of these genes.Quantitative polymerase chain reaction (qPCR) and immunohistochemical staining (IHC) were performed on primary thyroid cancers. Expression of COT was compared with clinicopathological characteristics including recurrence-free survival. Datasets from public repository (NCBI) were subjected to Gene Set Enrichment Analysis (GSEA).qPCR data showed that the relative mRNA expression of A-, B-, C-RAF and COT of PTC were higher than normal tissues (all P < 0.01). In addition, the expression of COT mRNA in PTC showed positive correlation with A- (r = 0.4083, P < 0.001), B- (r = 0.2773, P = 0.0003), and C-RAF (r = 0.5954, P < 0.001). The mRNA expressions of A-, B,- and C-RAF were also correlated with each other (all P < 0.001). In IHC, the staining intensities of B-RAF and COT were higher in PTC than in normal tissue (P < 0.001). Interestingly, moderate-to-strong staining intensities of B-RAF and COT were more frequent in B-RAF-positive PTC (P < 0.001, P = 0.013, respectively). In addition, aberrant expression of COT was related to old age at initial diagnosis (P = 0.045) and higher recurrence rate (P = 0.025). In multivariate analysis, tumor recurrence was persistently associated with moderate-to-strong staining of COT after adjusting for age, sex, extrathyroidal extension, multifocality, T-stage, N-stage, TNM stage, and B-RAF mutation (odds ratio, 4.662; 95% confidence interval 1.066 - 21.609; P = 0.045). Moreover, moderate-to-strong COT expression in PTC was associated with shorter recurrence-free survival (mean follow-up duration, 14.2 ± 4.1 years; P = 0.0403). GSEA indicated that gene sets related to B-RAF-RAS (P < 0.0001, false discovery rate [FDR] q-value = 0.000) and thyroid differentiation (P = 0.048, FDR q-value = 0.05) scores were enriched in lower COT expression group and gene sets such as T-cell receptor signaling pathway and Toll-like receptor signaling pathway are coordinately upregulated in higher COT expression group (both, P < 0.0001, FDR q-value = 0.000).Aberrant expression of A-, B-, and C-RAF, and COT is frequent in PTC; increased expression of COT is correlated with recurrence of PTC.

Alisoltani A, Fallahi H, Shiran B, et al.
RNA-seq SSRs and small RNA-seq SSRs: new approaches in cancer biomarker discovery.
Gene. 2015; 560(1):34-43 [PubMed] Related Publications
The recent exponential increase in the number of next generation sequencing studies provides a new source of data for the discovery of functional genomics based markers. The RNA-seq and small RNA-seq provide a new source for the discovery of differentially expressed SSRs (simple sequence repeats) as biomarkers in various diseases. In the present study, for the first time, we applied RNA-seq SSR to find new biomarkers for pancreatic cancer (PC) diagnosis. Analysis of RNA-seq data revealed a significant alternation in the frequency of SSR motifs during cancer progression. In particular, RNA-seq SSR showed an increase in the frequencies of GCC/GGC and GCG/CGC motifs in PC samples compared to healthy pancreas. These findings were further confirmed using meta-analysis of EST-SSR data in 11 different cancers. Interestingly, the genes containing GCC/GGC and GCG/CGC motifs in their sequences were involved in many cancer-related biological processes, particularly regulation processes. The small RNA-seq data were also mined for the conserved patterns in SSR frequencies (sRNA-seq SSR) during cancer progression. Based on the results, we suggest the potential use of GCC/GGC and GCG/CGC motifs as biomarkers in PC. Based on the findings of this study, it seems that RNA-seq SSR and sRNA-seq SSR could open a new paradigm in the diagnostic and even therapeutic strategies for PC along the other types of cancers.

Antony-Debré I, Manchev VT, Balayn N, et al.
Level of RUNX1 activity is critical for leukemic predisposition but not for thrombocytopenia.
Blood. 2015; 125(6):930-40 [PubMed] Free Access to Full Article Related Publications
To explore how RUNX1 mutations predispose to leukemia, we generated induced pluripotent stem cells (iPSCs) from 2 pedigrees with germline RUNX1 mutations. The first, carrying a missense R174Q mutation, which acts as a dominant-negative mutant, is associated with thrombocytopenia and leukemia, and the second, carrying a monoallelic gene deletion inducing a haploinsufficiency, presents only as thrombocytopenia. Hematopoietic differentiation of these iPSC clones demonstrated profound defects in erythropoiesis and megakaryopoiesis and deregulated expression of RUNX1 targets. iPSC clones from patients with the R174Q mutation specifically generated an increased amount of granulomonocytes, a phenotype reproduced by an 80% RUNX1 knockdown in the H9 human embryonic stem cell line, and a genomic instability. This phenotype, found only with a lower dosage of RUNX1, may account for development of leukemia in patients. Altogether, RUNX1 dosage could explain the differential phenotype according to RUNX1 mutations, with a haploinsufficiency leading to thrombocytopenia alone in a majority of cases whereas a more complete gene deletion predisposes to leukemia.

Biton A, Bernard-Pierrot I, Lou Y, et al.
Independent component analysis uncovers the landscape of the bladder tumor transcriptome and reveals insights into luminal and basal subtypes.
Cell Rep. 2014; 9(4):1235-45 [PubMed] Related Publications
Extracting relevant information from large-scale data offers unprecedented opportunities in cancerology. We applied independent component analysis (ICA) to bladder cancer transcriptome data sets and interpreted the components using gene enrichment analysis and tumor-associated molecular, clinicopathological, and processing information. We identified components associated with biological processes of tumor cells or the tumor microenvironment, and other components revealed technical biases. Applying ICA to nine cancer types identified cancer-shared and bladder-cancer-specific components. We characterized the luminal and basal-like subtypes of muscle-invasive bladder cancers according to the components identified. The study of the urothelial differentiation component, specific to the luminal subtypes, showed that a molecular urothelial differentiation program was maintained even in those luminal tumors that had lost morphological differentiation. Study of the genomic alterations associated with this component coupled with functional studies revealed a protumorigenic role for PPARG in luminal tumors. Our results support the inclusion of ICA in the exploitation of multiscale data sets.

Zeller G, Tap J, Voigt AY, et al.
Potential of fecal microbiota for early-stage detection of colorectal cancer.
Mol Syst Biol. 2014; 10:766 [PubMed] Free Access to Full Article Related Publications
Several bacterial species have been implicated in the development of colorectal carcinoma (CRC), but CRC-associated changes of fecal microbiota and their potential for cancer screening remain to be explored. Here, we used metagenomic sequencing of fecal samples to identify taxonomic markers that distinguished CRC patients from tumor-free controls in a study population of 156 participants. Accuracy of metagenomic CRC detection was similar to the standard fecal occult blood test (FOBT) and when both approaches were combined, sensitivity improved > 45% relative to the FOBT, while maintaining its specificity. Accuracy of metagenomic CRC detection did not differ significantly between early- and late-stage cancer and could be validated in independent patient and control populations (N = 335) from different countries. CRC-associated changes in the fecal microbiome at least partially reflected microbial community composition at the tumor itself, indicating that observed gene pool differences may reveal tumor-related host-microbe interactions. Indeed, we deduced a metabolic shift from fiber degradation in controls to utilization of host carbohydrates and amino acids in CRC patients, accompanied by an increase of lipopolysaccharide metabolism.

Lee HW, Cho HJ, Lee SJ, et al.
Tpl2 induces castration resistant prostate cancer progression and metastasis.
Int J Cancer. 2015; 136(9):2065-77 [PubMed] Related Publications
Progression to metastatic castration resistant prostate cancer (CRPC) is the major lethal pathway of prostate cancer (PC). Herein, we demonstrated that tumor progression locus 2 (Tpl2) kinase is the fundamental molecule provoking progression and metastasis of CRPC. Tpl2 upregulates CXCR4 and focal adhesion kinase (FAK) to activate CXCL12/CXCR4 and FAK/Akt signalling pathway. Consequently, epithelial-mesenchymal transition (EMT) and stemness of androgen depletion independent (ADI) PC cells are induced, which is dependent on the kinase activity of Tpl2. In vitro, proliferation, clonogenicity, migration, invasion and chemoresistance of ADI PC cells were enhanced by Tpl2. In vivo, Tpl2 overexpression and downregulation showed significant stimulatory and inhibitory effects on tumorigenic and metastatic potential of ADI PC cells, respectively. Moreover, the prognostic effects of Tpl2 and expressional correlation between Tpl2 and EMT-related molecules/CXCR4 were validated in clinical PC databases. Since Tpl2 exerts metastatic progression promoting activities in CRPC, Tpl2 could serve as a novel therapeutic target for metastatic CRPC.

Couderc C, Bollard J, Couté Y, et al.
Mechanisms of local invasion in enteroendocrine tumors: identification of novel candidate cytoskeleton-associated proteins in an experimental mouse model by a proteomic approach and validation in human tumors.
Mol Cell Endocrinol. 2015; 399:154-63 [PubMed] Related Publications
Small-intestinal neuroendocrine tumors (SI-NETs) are defined as locally invasive only after extension to the muscularis propria. To gain further insight into the molecular mechanisms, we applied a proteomic approach to an orthotopic xenograft model to identify candidate proteins evaluable in human SI-NETs. After grafting STC-1 neuroendocrine tumor cells on the caecum of nude mice, comparative proteomic studies were performed between the pre-invasive and the invasive stages, respectively 2 and 8 weeks after grafting. We identified 24 proteins displaying at least a 1.5-fold differential expression between 2 and 8 week-stages. Most were cytoskeleton-associated proteins, among which five showed decreasing expression levels (CRMP2, TCP1ε, TPM2, vimentin, desmin) and two increasing expression levels (14-3-3γ, CK8). Changes for CRMP2, TCP1ε, TPM2 and 14-3-3γ were confirmed in experimental tumors and in a series of 28 human SI-NETs. In conclusion, our results underline the relevance of proteomics to identify novel biomarkers of tissue invasion.

Bossard C, Dobay MP, Parrens M, et al.
Immunohistochemistry as a valuable tool to assess CD30 expression in peripheral T-cell lymphomas: high correlation with mRNA levels.
Blood. 2014; 124(19):2983-6 [PubMed] Related Publications
The extended use of brentuximab-vedotin was reported for CD30(+) nonanaplastic peripheral T-cell lymphomas (PTCLs) with promising efficacy. CD30 status assessment is thus a critical factor for therapeutic decision, but the reliability of immunohistochemistry (IHC) in evaluating its expression remains to be defined. This prompted us to investigate the correlation between semiquantitative CD30 protein assessment by IHC and messenger RNA (mRNA) assessment by microarrays in a cohort of 376 noncutaneous PTCLs representative of the main entities. By IHC, CD30 expression was heterogeneous across and within entities and significantly associated with large tumor cell size. In addition to 100% anaplastic large-cell lymphomas, 57% of other PTCL entities were CD30-positive at a 5% threshold. CD30 protein expression was highly correlated to mRNA levels. mRNA levels were bimodal, separating high from low CD30-expressing PTCL cases. We conclude that IHC is a valuable tool in clinical practice to assess CD30 expression in PTCLs.

Ohta T, Kim YH, Oh JE, et al.
Alterations of the RRAS and ERCC1 genes at 19q13 in gemistocytic astrocytomas.
J Neuropathol Exp Neurol. 2014; 73(10):908-15 [PubMed] Related Publications
Gemistocytic astrocytoma (World Health Organization grade II) is a rare variant of diffuse astrocytoma that is characterized by the presence of neoplastic gemistocytes and has a significantly less favorable prognosis. Other than frequent TP53 mutations (>80%), little is known about its molecular profile. Here, we show that gemistocytic astrocytomas carry a lower frequency of IDH mutations than fibrillary astrocytomas (74% vs 92%; p = 0.0255) but have profiles similar to those of fibrillary astrocytomas with respect to TERT promoter mutations (5% vs 0%), 1p/19q loss (10% vs 8%), and loss of heterozygosity 10q (10% vs 12%). Exome sequencing in 5 gemistocytic astrocytomas revealed homozygous deletion of genes at 19q13 (i.e. RRAS [related RAS viral oncogene homolog; 2 cases] and ERCC1 [excision repair cross-complementing rodent repair deficiency, complementation group 1; 1 case]). Further screening showed RRAS homozygous deletion in 7 of 42 (17%) gemistocytic astrocytomas and in 3 of 24 (13%) IDH1 mutated secondary glioblastomas. Patients with gemistocytic astrocytoma and secondary glioblastoma with an RRAS deletion tended to have shorter survival rates than those without deletion. Differential polymerase chain reaction and methylation-specific polymerase chain reaction revealed an ERCC1 homozygous deletion or promoter methylation in 10 of 42 (24%) gemistocytic astrocytomas and in 8 of 24 (33%) secondary glioblastomas. Alterations in RRAS and ERCC1 appear to be typical in gemistocytic astrocytomas and secondary glioblastomas, since they were not present in 49 fibrillary astrocytomas or 30 primary glioblastomas.

Hosseinpour B, Bakhtiarizadeh MR, Mirabbassi SM, Ebrahimie E
Comparison of hematopoietic cancer stem cells with normal stem cells leads to discovery of novel differentially expressed SSRs.
Gene. 2014; 550(1):10-7 [PubMed] Related Publications
Tandem repeat expansion in the transcriptomics level has been considered as one of the underlying causes of different cancers. Cancer stem cells are a small portion of cancer cells within the main neoplasm and can remain alive during chemotherapy and re-induce tumor growth. The EST-SSR background of cancer stem cells and possible roles of expressed SSRs in altering normal stem cells to cancer ones have not been investigated yet. Here, SSR distributions in hematopoietic normal and cancer stem cells were compared based on the expressed EST-SSR. One hundred eighty nine and 223 EST-SSRs were identified in cancer and normal stem cells, respectively. The EST-SSR expression pattern was significantly different between normal and cancer stem cells. The frequencies of AC/GT and TA/TA EST-SSRs were about 10% higher in cancer than normal stem cells. Remarkably, the number of triplets in cancer stem cells was 1.5 times higher than that in normal stem cells. GAT EST-SSR was frequent in cancer stem cells, but, conversely, normal stem cells did not express GAT EST-SSR. We suggest this EST-SSR as a novel triplet in cancer stem cell induction. Translating EST-SSRs to amino acids demonstrated that Asp and Ile were more abundant in cancer stem cells compared to normal stem cells. Finally, Gene Ontology (GO) enrichment analysis was carried out on genes containing triplet SSRs and showed that SSRs intentionally visit some specific GO classes. Interestingly, a NF-kappa (nuclear factor-kB) binding transcription factor was significantly hit by SSR instability which is a hallmark for leukemia stem cells. NF-kappa is an over represented transcription factor during cancer progression. It seems that there is a crosstalk between the NF-kB transcription factor and expressed GAT tandem repeat which negatively regulate apoptosis. In addition to better understanding of tumorigenesis, the findings of this study offer new DNA markers for diagnostic purposes and identifying at risk populations. In addition, a new approach for gene discovery in cancer by target analysis of differentially expressed EST-SSRs between cancer and normal stem cells is presented here.

Piaton E, Casalegno JS, Advenier AS, et al.
p16(INK4a) overexpression is not linked to oncogenic human papillomaviruses in patients with high-grade urothelial cancer cells.
Cancer Cytopathol. 2014; 122(10):760-9 [PubMed] Related Publications
BACKGROUND: p16(INK4a) Is overexpressed in almost all precancerous and carcinomatous lesions of the uterine cervix, secondary to interference between high-risk human papillomaviruses (hr-HPVs) and the retinoblastoma gene product. Overexpression of p16(INK4a) has also been identified in patients with high-grade urothelial lesions, both cytologically and histologically. However, the etiological role of HPV has not been documented except in inverted papillomas, low-grade bladder tumors, and younger patients. We therefore attempted to verify if HPV DNA was detectable in p16(INK4a) -positive urothelial tumors.
METHODS: A total of 90 urinary cytology samples (33 negative/low-grade cases and 57 high-grade proliferations) were analyzed for p16(INK4a) and HPV DNA. HPV genotyping was performed by polymerase chain reaction using a low-density DNA microarray enabling the detection of 35 HPVs. A reasoned approach combining tissue genotyping and in situ hybridization (ISH) for hr-HPVs was used in patients with urinary HPV.
RESULTS: Low-risk HPV (HPV-84) and hr-HPVs (HPV-16, -31, and -70) were detected. The prevalence of hr-HPVs in the urine was low: 5 of 82 patients (6.1%) and only 4 of 50 patients (8.0%) with high-grade urothelial malignancy. p16(INK4a) overexpression was noted in 49 high-grade samples (85.9%). In patients with p16(INK4a) -positive tumor cells and hr-HPV in the urine, HPV genotyping and ISH for hr-HPVs were negative in matched tissue sections.
CONCLUSIONS: Our study shows a low prevalence of hr-HPVs in the urine of patients with high-grade urothelial malignancy. In those, p16(INK4a) overexpression occurs in the absence of demonstrable HPV DNA in the tissue sections, contrary to what is noted in gynecopathology.

Rebouissou S, Bernard-Pierrot I, de Reyniès A, et al.
EGFR as a potential therapeutic target for a subset of muscle-invasive bladder cancers presenting a basal-like phenotype.
Sci Transl Med. 2014; 6(244):244ra91 [PubMed] Related Publications
Muscle-invasive bladder carcinoma (MIBC) constitutes a heterogeneous group of tumors with a poor outcome. Molecular stratification of MIBC may identify clinically relevant tumor subgroups and help to provide effective targeted therapies. From seven series of large-scale transcriptomic data (383 tumors), we identified an MIBC subgroup accounting for 23.5% of MIBC, associated with shorter survival and displaying a basal-like phenotype, as shown by the expression of epithelial basal cell markers. Basal-like tumors presented an activation of the epidermal growth factor receptor (EGFR) pathway linked to frequent EGFR gains and activation of an EGFR autocrine loop. We used a 40-gene expression classifier derived from human tumors to identify human bladder cancer cell lines and a chemically induced mouse model of bladder cancer corresponding to human basal-like bladder cancer. We showed, in both models, that tumor cells were sensitive to anti-EGFR therapy. Our findings provide preclinical proof of concept that anti-EGFR therapy can be used to target a subset of particularly aggressive MIBC tumors expressing basal cell markers and provide diagnostic tools for identifying these tumors.

Thomin A, Friszer S, Fajac A, et al.
Hormonal prevention of breast cancer.
Ann Endocrinol (Paris). 2014; 75(3):148-55 [PubMed] Related Publications
Breast cancer prevention can be provided by using SERMs or aromatase inhibitors depending on the ovarian status, with a global risk reduction of 50 to 60%. Prophylactic annexectomy offered to reduce ovarian risk in BRCA mutation carriers also lowers breast cancer risk by 50%. Main side effects include deep vein thrombosis for SERMs, hot flushes and joint pain (although less frequently than initially suspected) with aromatase inhibitors. Other strategies based on progesterone, insulin or prolactin signaling modulation may be offered in the future. Criteria for candidate selection remain to be established.

Nozières C, Zhang CX, Buffet A, et al.
p.Ala541Thr variant of MEN1 gene: a non deleterious polymorphism or a pathogenic mutation?
Ann Endocrinol (Paris). 2014; 75(3):133-40 [PubMed] Related Publications
CONTEXT: Multiple Endocrine Neoplasia Type 1 (MEN1) is an autosomal dominant inherited syndrome, related to mutations in the MEN1 gene. Controversial data suggest that the nonsynonymous p.Ala541Thr variant, usually considered as a non-pathogenic polymorphism, may be associated with an increased risk of MEN1-related lesions in carriers.
OBJECTIVE: The aim of this study was to evaluate the pathogenic influence of the p.Ala541Thr variant on clinical and functional outcomes.
PATIENTS AND METHODS: We analysed a series of 55 index patients carrying the p.Ala541Thr variant. Their clinical profile was compared to that of 117 MEN1 patients. The biological impact of the p.Ala541Thr variant on cell growth was additionally investigated on menin-deficient Leydig cell tumour (LCT)10 cells generated from Men1+/Men1- heterozygous knock-out mice, and compared with wild type (WT).
RESULTS: The mean age at first appearance of endocrine lesions was similar in both p.Ala541Thr carriers and MEN1 patients, but no p.Ala541Thr patient had more than one cardinal MEN1 lesion at initial diagnosis. A second MEN1 lesion was diagnosed in 13% of MEN1 patients and in 7% of p.Ala541Thr carriers in the year following preliminary diagnosis. Functional studies on LCT10 cells showed that overexpression of the p.Ala541Thr variant did not inhibit cell growth, which is in direct contrast to results obtained from investigation of WT menin protein.
CONCLUSION: Taken together, these data raise the question of a potential pathogenicity of the p.Ala541Thr missense variant of menin that commonly occurs within the general population. Additional studies are required to investigate whether it may be involved in a low-penetrance MEN1 phenotype.

David M, Sahay D, Mege F, et al.
Identification of heparin-binding EGF-like growth factor (HB-EGF) as a biomarker for lysophosphatidic acid receptor type 1 (LPA1) activation in human breast and prostate cancers.
PLoS One. 2014; 9(5):e97771 [PubMed] Free Access to Full Article Related Publications
Lysophosphatidic acid (LPA) is a natural bioactive lipid with growth factor-like functions due to activation of a series of six G protein-coupled receptors (LPA₁₋₆). LPA receptor type 1 (LPA₁) signaling influences the pathophysiology of many diseases including cancer, obesity, rheumatoid arthritis, as well as lung, liver and kidney fibrosis. Therefore, LPA₁ is an attractive therapeutic target. However, most mammalian cells co-express multiple LPA receptors whose co-activation impairs the validation of target inhibition in patients because of missing LPA receptor-specific biomarkers. LPA₁ is known to induce IL-6 and IL-8 secretion, as also do LPA₂ and LPA₃. In this work, we first determined the LPA induced early-gene expression profile in three unrelated human cancer cell lines expressing different patterns of LPA receptors (PC3: LPA₁,₂,₆; MDA-MB-231: LPA1,2; MCF-7: LPA₂,₆). Among the set of genes upregulated by LPA only in LPA₁-expressing cells, we validated by QPCR and ELISA that upregulation of heparin-binding EGF-like growth factor (HB-EGF) was inhibited by LPA₁-₃ antagonists (Ki16425, Debio0719). Upregulation and downregulation of HB-EGF mRNA was confirmed in vitro in human MDA-B02 breast cancer cells stably overexpressing LPA₁ (MDA-B02/LPA₁) and downregulated for LPA₁ (MDA-B02/shLPA1), respectively. At a clinical level, we quantified the expression of LPA₁ and HB-EGF by QPCR in primary tumors of a cohort of 234 breast cancer patients and found a significantly higher expression of HB-EGF in breast tumors expressing high levels of LPA₁. We also generated human xenograph prostate tumors in mice injected with PC3 cells and found that a five-day treatment with Ki16425 significantly decreased both HB-EGF mRNA expression at the primary tumor site and circulating human HB-EGF concentrations in serum. All together our results demonstrate that HB-EGF is a new and relevant biomarker with potentially high value in quantifying LPA₁ activation state in patients receiving anti-LPA₁ therapies.

Charbonneau B, Moysich KB, Kalli KR, et al.
Large-scale evaluation of common variation in regulatory T cell-related genes and ovarian cancer outcome.
Cancer Immunol Res. 2014; 2(4):332-40 [PubMed] Free Access to Full Article Related Publications
The presence of regulatory T cells (Treg) in solid tumors is known to play a role in patient survival in ovarian cancer and other malignancies. We assessed inherited genetic variations via 749 tag single-nucleotide polymorphisms (SNP) in 25 Treg-associated genes (CD28, CTLA4, FOXP3, IDO1, IL10, IL10RA, IL15, 1L17RA, IL23A, IL23R, IL2RA, IL6, IL6R, IL8, LGALS1, LGALS9, MAP3K8, STAT5A, STAT5B, TGFB1, TGFB2, TGFB3, TGFBR1, TGRBR2, and TGFBR3) in relation to ovarian cancer survival. We analyzed genotype and overall survival in 10,084 women with invasive epithelial ovarian cancer, including 5,248 high-grade serous, 1,452 endometrioid, 795 clear cell, and 661 mucinous carcinoma cases of European descent across 28 studies from the Ovarian Cancer Association Consortium (OCAC). The strongest associations were found for endometrioid carcinoma and IL2RA SNPs rs11256497 [HR, 1.42; 95% confidence interval (CI), 1.22-1.64; P = 5.7 × 10(-6)], rs791587 (HR, 1.36; 95% CI, 1.17-1.57; P = 6.2 × 10(-5)), rs2476491 (HR, = 1.40; 95% CI, 1.19-1.64; P = 5.6 × 10(-5)), and rs10795763 (HR, 1.35; 95% CI, 1.17-1.57; P = 7.9 × 10(-5)), and for clear cell carcinoma and CTLA4 SNP rs231775 (HR, 0.67; 95% CI, 0.54-0.82; P = 9.3 × 10(-5)) after adjustment for age, study site, population stratification, stage, grade, and oral contraceptive use. The rs231775 allele associated with improved survival in our study also results in an amino acid change in CTLA4 and previously has been reported to be associated with autoimmune conditions. Thus, we found evidence that SNPs in genes related to Tregs seem to play a role in ovarian cancer survival, particularly in patients with clear cell and endometrioid epithelial ovarian cancer.

Tokinaga A, Furuya M, Niino H, et al.
Colonic low-grade endometrial stromal sarcoma and orthotopic endometrial stromal tumor with limited infiltration sharing the JAZF1-SUZ12 gene fusion.
Pathol Int. 2014; 64(4):178-82 [PubMed] Related Publications
Endometrial stromal tumors (ESTs) are composed of cells resembling endometrial stroma, and are divided into benign and malignant types based on morphology. Endometrial stromal nodule (ESN) is a benign localized tumor, and endometrial stromal sarcoma (ESS) is an infiltrative and potentially metastatic neoplasm. A series of genetic aberrations contribute to pathological diagnosis of ESTs. At present, subsets of ESN and ESS-low grade (ESS-LG) are characterized as JAZF1-SUZ12/JJAZ1 gene fusion. The ESTs that show higher grade atypia but lack nuclear pleomorphism include YWHAE-FAM22 ESS. Here we report an unusual case of ESTs. Sudden colonic perforation occurred to the patient, and emergency surgery was performed. Pathological findings suggested metastatic ESS. Thorough medical examination of the genital organs detected a 1 cm-sized well-demarcated uterine tumor. Microscopically, the tumor lacked infiltrative features, conforming to the definition of ESN. Both lesions demonstrated identical cytology and shared JAZF1-SUZ12 gene fusion. Endometriosis was not found in any areas of the resected organs, strongly suggesting that the uterine orthotopic tumor metastasized. The current case uncovered the problems of differential diagnosis between ESN and ESS-LG. We demonstrate detailed pathological features of the two lesions, and discuss the possibility of orthotopic EST with limited infiltration to develop into ESS-LG.

Hope C, Ollar SJ, Heninger E, et al.
TPL2 kinase regulates the inflammatory milieu of the myeloma niche.
Blood. 2014; 123(21):3305-15 [PubMed] Free Access to Full Article Related Publications
Targeted modulation of microenvironmental regulatory pathways may be essential to control myeloma and other genetically/clonally heterogeneous cancers. Here we report that human myeloma-associated monocytes/macrophages (MAM), but not myeloma plasma cells, constitute the predominant source of interleukin-1β (IL-1β), IL-10, and tumor necrosis factor-α at diagnosis, whereas IL-6 originates from stromal cells and macrophages. To dissect MAM activation/cytokine pathways, we analyzed Toll-like receptor (TLR) expression in human myeloma CD14(+) cells. We observed coregulation of TLR2 and TLR6 expression correlating with local processing of versican, a proteoglycan TLR2/6 agonist linked to carcinoma progression. Versican has not been mechanistically implicated in myeloma pathogenesis. We hypothesized that the most readily accessible target in the versican-TLR2/6 pathway would be the mitogen-activated protein 3 (MAP3) kinase, TPL2 (Cot/MAP3K8). Ablation of Tpl2 in the genetically engineered in vivo myeloma model, Vκ*MYC, led to prolonged disease latency associated with plasma cell growth defect. Tpl2 loss abrogated the "inflammatory switch" in MAM within nascent myeloma lesions and licensed macrophage repolarization in established tumors. MYC activation/expression in plasma cells was independent of Tpl2 activity. Pharmacologic TPL2 inhibition in human monocytes led to dose-dependent attenuation of IL-1β induction/secretion in response to TLR2 stimulation. Our results highlight a TLR2/6-dependent TPL2 pathway as novel therapeutic target acting nonautonomously through macrophages to control myeloma progression.

Feichtinger J, McFarlane RJ, Larcombe LD
CancerEST: a web-based tool for automatic meta-analysis of public EST data.
Database (Oxford). 2014; 2014(0):bau024 [PubMed] Free Access to Full Article Related Publications
The identification of cancer-restricted biomarkers is fundamental to the development of novel cancer therapies and diagnostic tools. The construction of comprehensive profiles to define tissue- and cancer-specific gene expression has been central to this. To this end, the exploitation of the current wealth of 'omic'-scale databases can be facilitated by automated approaches, allowing researchers to directly address specific biological questions. Here we present CancerEST, a user-friendly and intuitive web-based tool for the automated identification of candidate cancer markers/targets, for examining tissue specificity as well as for integrated expression profiling. CancerEST operates by means of constructing and meta-analyzing expressed sequence tag (EST) profiles of user-supplied gene sets across an EST database supporting 36 tissue types. Using a validation data set from the literature, we show the functionality and utility of CancerEST. DATABASE URL:

de'Angelis N, Memeo R, Zuddas V, et al.
Laparoscopic surgery for double gastrointestinal stromal tumor of the stomach: a report of two cases.
World J Surg Oncol. 2014; 12:76 [PubMed] Free Access to Full Article Related Publications
Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that originate from interstitial cells of Cajal or their stem cell-like precursors. Generally, GISTs have specific c-KIT gene mutations. The incidence of GISTs is estimated to be 10 to 20 cases/one million individuals, and GISTs typically affect people over 50 years of age. The majority of GISTs are solitary. However, multifocal GISTs have been observed, especially in children. We report on two unusual adult cases of double GISTs that were treated by laparoscopic surgery. The first patient presented a polypoid mass of the fundus and a second isolated smaller tumor in the posterior wall of the lesser curvature of the stomach. A histopathological examination confirmed that both tumors were GISTs and were c-KIT-positive. A total laparoscopic gastrectomy was performed. In the second patient, GISTs were identified at the level of the fundus and the greater curvature of the stomach. A laparoscopic partial sleeve gastrectomy was performed. Both surgeries were successful with no complications or relapses at three to five years following surgery.

Milia-Argeiti E, Mourah S, Vallée B, et al.
EMMPRIN/CD147-encriched membrane vesicles released from malignant human testicular germ cells increase MMP production through tumor-stroma interaction.
Biochim Biophys Acta. 2014; 1840(8):2581-8 [PubMed] Related Publications
BACKGROUND: Elevated levels of EMMPRIN/CD147 in cancer tissues have been correlated with tumor progression but the regulation of its expression is not yet understood. Here, the regulation of EMMPRIN expression was investigated in testicular germ cell tumor (TGCTs) cell lines.
METHODS: EMMPRIN expression in seminoma JKT-1 and embryonal carcinoma NT2/D1 cell lines was determined by Western blot, immunofluorescence and qRT-PCR. Membrane vesicles (MVs) secreted from these cells, treated or not with EMMPRIN siRNA, were isolated by differential centrifugations of their conditioned medium. MMP-2 was analyzed by zymography and qRT-PCR.
RESULTS: The more aggressive embryonic carcinoma NT2/D1 cells expressed more EMMPRIN mRNA than the seminoma JKT-1 cells, but surprisingly contained less EMMPRIN protein, as determined by immunoblotting and immunostaining. The protein/mRNA discrepancy was not due to accelerated protein degradation in NT2/D1 cells, but by the secretion of EMMPRIN within MVs, as the vesicles released from NT2/D1 contained considerably more EMMPRIN than those released from JKT-1. EMMPRIN-containing MVs obtained from NT2/D1, but not from EMMPRIN-siRNA treated NT2/D1, increased MMP-2 production in fibroblasts to a greater extent than those from JKT-1 cells.
CONCLUSION AND GENERAL SIGNIFICANCE: The data presented show that the more aggressive embryonic carcinoma cells synthesize more EMMPRIN than seminoma cells, but which they preferentially target to secreted MVs, unlike seminoma cells which retain EMMPRIN within the cell membrane. This cellular event points to a mechanism by which EMMPRIN expressed by malignant testicular cells can exert its MMP inducing effect on distant cells within the tumor microenvironment to promote tumor invasion. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.

Gunawardana J, Chan FC, Telenius A, et al.
Recurrent somatic mutations of PTPN1 in primary mediastinal B cell lymphoma and Hodgkin lymphoma.
Nat Genet. 2014; 46(4):329-35 [PubMed] Related Publications
Classical Hodgkin lymphoma and primary mediastinal B cell lymphoma (PMBCL) are related lymphomas sharing pathological, molecular and clinical characteristics. Here we discovered by whole-genome and whole-transcriptome sequencing recurrent somatic coding-sequence mutations in the PTPN1 gene. Mutations were found in 6 of 30 (20%) Hodgkin lymphoma cases, in 6 of 9 (67%) Hodgkin lymphoma-derived cell lines, in 17 of 77 (22%) PMBCL cases and in 1 of 3 (33%) PMBCL-derived cell lines, consisting of nonsense, missense and frameshift mutations. We demonstrate that PTPN1 mutations lead to reduced phosphatase activity and increased phosphorylation of JAK-STAT pathway members. Moreover, silencing of PTPN1 by RNA interference in Hodgkin lymphoma cell line KM-H2 resulted in hyperphosphorylation and overexpression of downstream oncogenic targets. Our data establish PTPN1 mutations as new drivers in lymphomagenesis.

Kim K, Kim G, Kim JY, et al.
Interleukin-22 promotes epithelial cell transformation and breast tumorigenesis via MAP3K8 activation.
Carcinogenesis. 2014; 35(6):1352-61 [PubMed] Related Publications
Interleukin-22 (IL-22), one of the cytokines secreted by T-helper 17 (Th17) cells, binds to a class II cytokine receptor containing an IL-22 receptor 1 (IL-22R1) and IL-10R2 and influences a variety of immune reactions. IL-22 has also been shown to modulate cell cycle and proliferation mediators such as extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), but little is known about the underlying molecular mechanisms of IL-22 in tumorigenesis. In this paper, we propose that IL-22 has a crucial role to play in controlling epithelial cell proliferation and tumorigenesis in the breast. IL-22 increased MAP3K8 phosphorylation through IL-22R1, followed by the induction of MEK-ERK, JNK-c-Jun, and STAT3 signaling pathways. Furthermore, IL-22-IL-22R1 signaling pathway activated activator protein-1 and HER2 promoter activity. In addition, Pin1 was identified as a key positive regulator for the phosphorylation-dependent MEK, c-Jun and STAT3 activity induced by IL-22. Pin1(-/-) mouse embryonic fibroblasts (MEF) exhibited significantly a decrease in IL-22-induced MEK1/2, c-Jun, and STAT3 phosphorylation compared with Pin1(+/+) MEF. In addition, a knockdown of Pin1 prevented phosphorylation induced by IL-22. The in vivo chorioallantoic membrane assay also showed that IL-22 increased tumor formation of JB6 Cl41 cells. Moreover, the knockdown of MAP3K8 and Pin1 attenuated tumorigenicity of MCF7 cells. Consistent with these observations, IL-22 levels positively correlate with MAP3K8 and Pin1 expression in human breast cancer. Overall, our findings point to a critical role for the IL-22-induced MAP3K8 signaling pathway in promoting cancer-associated inflammation in the tumor microenvironment.

André F, Bachelot T, Commo F, et al.
Comparative genomic hybridisation array and DNA sequencing to direct treatment of metastatic breast cancer: a multicentre, prospective trial (SAFIR01/UNICANCER).
Lancet Oncol. 2014; 15(3):267-74 [PubMed] Related Publications
BACKGROUND: Breast cancer is characterised by genomic alterations. We did a multicentre molecular screening study to identify abnormalities in individual patients with the aim of providing targeted therapy matched to individuals' genomic alterations.
METHODS: From June 16, 2011, to July 30, 2012, we recruited patients who had breast cancer with a metastasis accessible for biopsy in 18 centres in France. Comparative genomic hybridisation (CGH) array and Sanger sequencing on PIK3CA (exon 10 and 21) and AKT1 (exon 4) were used to assess metastatic biopsy samples in five centres. Therapeutic targets were decided on the basis of identified genomic alterations. The primary objective was to include 30% of patients in clinical trials testing a targeted therapy and, therefore, the primary outcome was the proportion of patients to whom a targeted therapy could be offered. For the primary endpoint, the analyses were done on the overall population registered for the trial. This trial is registered with, number NCT01414933.
FINDINGS: 423 patients were included, and biopsy samples were obtained from 407 (metastatic breast cancer was not found in four). CGH array and Sanger sequencing were feasible in 283 (67%) and 297 (70%) patients, respectively. A targetable genomic alteration was identified in 195 (46%) patients, most frequently in PIK3CA (74 [25%] of 297 identified genomic alterations), CCND1 (53 [19%]), and FGFR1 (36 [13%]). 117 (39%) of 297 patients with genomic tests available presented with rare genomic alterations (defined as occurring in less than 5% of the general population), including AKT1 mutations, and EGFR, MDM2, FGFR2, AKT2, IGF1R, and MET high-level amplifications. Therapy could be personalised in 55 (13%) of 423 patients. Of the 43 patients who were assessable and received targeted therapy, four (9%) had an objective response, and nine others (21%) had stable disease for more than 16 weeks. Serious (grade 3 or higher) adverse events related to biopsy were reported in four (1%) of enrolled patients, including pneumothorax (grade 3, one patient), pain (grade 3, one patient), haematoma (grade 3, one patient), and haemorrhagic shock (grade 3, one patient).
INTERPRETATION: Personalisation of medicine for metastatic breast cancer is feasible, including for rare genomic alterations.
FUNDING: French National Cancer Institute, Breast Cancer Research Foundation, Odyssea, Operation Parrains Chercheurs.

Seddiki N, Brezar V, Ruffin N, et al.
Role of miR-155 in the regulation of lymphocyte immune function and disease.
Immunology. 2014; 142(1):32-8 [PubMed] Free Access to Full Article Related Publications
MicroRNAs (miRNAs) have emerged as critical regulators of gene expression within cells. One particular miRNA, miR-155, is highly expressed within lymphocytes (both B and T cells) and mediates a number of important roles. These include shaping the transcriptome of lymphoid cells that control diverse biological functions vital in adaptive immunity. The use of mice engineered to be deficient in miR-155, as well as the identification of endogenous targets of miR-155 in T cells by transcriptome-wide analysis, has helped to unravel the crucial role that this miRNA plays in fine tuning the regulation of lymphocyte subsets such as B cells, CD8(+) and CD4(+) T cells ranging from T helper type 1 (Th1), Th2, Th17 and regulatory T cells. In this review, we summarize what we have learned about miR-155 in the regulation of lymphocyte responses at the cellular and molecular levels and in particular, we focus on the recent findings showing that miR-155 shapes the balance between tolerance and immunity.

Kim G, Khanal P, Kim JY, et al.
COT phosphorylates prolyl-isomerase Pin1 to promote tumorigenesis in breast cancer.
Mol Carcinog. 2015; 54(6):440-8 [PubMed] Related Publications
Pin1, a conserved eukaryotic Peptidyl-prolyl cis/trans isomerase, has profound effects on numerous key-signaling molecules, and its deregulation contributes to disease, particularly cancer. Although Pin1-mediated prolyl isomerization is an essential and novel regulatory mechanism for protein phosphorylation, little is known about the upstream signaling pathway(s) that regulates Pin1 activity. Here, we identify MAP3K-related serine-threonine kinase (the gene encoding COT/Tpl2) as a kinase responsible for phosphorylation of Pin1 Ser16. COT interacts with and phosphorylates Pin1 on Ser16. Consequently, Pin1 Ser16 phosphorylation by COT increases cyclin D1 abundance and enhances tumorigenecity of MCF7 cells. In contrast, depletion of COT in MCF7 cells leads to downregulation of Pin1 Ser16 phosphorylation, which subsequently decrease cyclin D1 levels, inhibiting tumorigenecity of MCF7 cells. In a xenograft model, treatment of TKI, a COT inhibitor, and Juglone, a Pin1 inhibitor, abrogates tumor growth. In human breast cancer patients, immunohistochemical staining shows that Pin1 pSer16 levels are positively correlated with COT levels, providing strong evidence for an essential role of the COT/Pin1 axis in conveying oncogenic signals to promote aggressiveness in human breast cancer.

Luscan A, Shackleford G, Masliah-Planchon J, et al.
The activation of the WNT signaling pathway is a Hallmark in neurofibromatosis type 1 tumorigenesis.
Clin Cancer Res. 2014; 20(2):358-71 [PubMed] Related Publications
PURPOSE: The hallmark of neurofibromatosis type 1 (NF1) is the onset of dermal or plexiform neurofibromas, mainly composed of Schwann cells. Plexiform neurofibromas can transform into malignant peripheral nerve sheath tumors (MPNST) that are resistant to therapies.
EXPERIMENTAL DESIGN: The aim of this study was to identify an additional pathway in the NF1 tumorigenesis. We focused our work on Wnt signaling that is highly implicated in cancer, mainly in regulating the proliferation of cancer stem cells. We quantified mRNAs of 89 Wnt pathway genes in 57 NF1-associated tumors including dermal and plexiform neurofibromas and MPNSTs. Expression of two major stem cell marker genes and five major epithelial-mesenchymal transition marker genes was also assessed. The expression of significantly deregulated Wnt genes was then studied in normal human Schwann cells, fibroblasts, endothelial cells, and mast cells and in seven MPNST cell lines.
RESULTS: The expression of nine Wnt genes was significantly deregulated in plexiform neurofibromas in comparison with dermal neurofibromas. Twenty Wnt genes showed altered expression in MPNST biopsies and cell lines. Immunohistochemical studies confirmed the Wnt pathway activation in NF1-associated MPNSTs. We then confirmed that the knockdown of NF1 in Schwann cells but not in epithelial cells provoked the activation of Wnt pathway by functional transfection assays. Furthermore, we showed that the protein expression of active β-catenin was increased in NF1-silenced cell lines. Wnt pathway activation was strongly associated to both cancer stem cell reservoir and Schwann-mesenchymal transition.
CONCLUSION: We highlighted the implication of Wnt pathway in NF1-associated tumorigenesis.

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