Gene Summary

Gene:MAP2K1; mitogen-activated protein kinase kinase 1
Aliases: CFC3, MEK1, MKK1, MAPKK1, PRKMK1
Summary:The protein encoded by this gene is a member of the dual specificity protein kinase family, which acts as a mitogen-activated protein (MAP) kinase kinase. MAP kinases, also known as extracellular signal-regulated kinases (ERKs), act as an integration point for multiple biochemical signals. This protein kinase lies upstream of MAP kinases and stimulates the enzymatic activity of MAP kinases upon wide variety of extra- and intracellular signals. As an essential component of MAP kinase signal transduction pathway, this kinase is involved in many cellular processes such as proliferation, differentiation, transcription regulation and development. [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, GeneCard, Gene
Protein:dual specificity mitogen-activated protein kinase kinase 1
Source:NCBIAccessed: 21 August, 2015


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 21 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.

  • Young Adult
  • Mitogen-Activated Protein Kinase 3
  • Signal Transduction
  • fms-Like Tyrosine Kinase 3
  • Transformation, Genetic
  • Transfection
  • MAP Kinase Kinase 1
  • ets-Domain Protein Elk-1
  • Thyroid Cancer
  • Transcription Factors
  • Mitogen-Activated Protein Kinase Kinases
  • Sulfonamides
  • STAT5 Transcription Factor
  • Receptor, Platelet-Derived Growth Factor beta
  • Cell Proliferation
  • Tumor Markers
  • Apoptosis
  • Skin Abnormalities
  • c-MET
  • Tumor Stem Cell Assay
  • Tetradecanoylphorbol Acetate
  • Survival Rate
  • Protein-Serine-Threonine Kinases
  • Transduction
  • Chromosome 15
  • ran GTP-Binding Protein
  • Vimentin
  • Tubulin
  • Receptor, erbB-2
  • beta Catenin
  • Phosphorylation
  • Proto-Oncogene Proteins
  • Ultraviolet Rays
  • MAP Kinase Kinase 2
  • MAP Kinase Signaling System
  • Mitogen-Activated Protein Kinase 1
  • Cancer Gene Expression Regulation
  • von Hippel-Lindau Disease
  • Sensitivity and Specificity
  • Xenograft Models
Tag cloud generated 21 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (2)

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: MAP2K1 (cancer-related)

Goda AE, Erikson RL, Ahn JS, Kim BY
Induction of G1 Arrest by SB265610 Involves Cyclin D3 Down-regulation and Suppression of CDK2 (Thr160) Phosphorylation.
Anticancer Res. 2015; 35(6):3235-43 [PubMed] Related Publications
BACKGROUND/AIM: The current study investigated the mechanisms underlying the antitumor activity of SB265610, a cysteine-amino acid-cysteine (CXC) chemokines receptor 2 (CXCR2) antagonist.
MATERIALS AND METHODS: Cell-cycle progression and regulatory molecules were assessed by flow cytometry, immunoblotting, real-time PCR and immunoprecipitation. Target validation was achieved via RNA interference.
RESULTS: G1 arrest induced by SB265610 occurred at concentrations lacking CXCR2 selectivity, persisted upon interleukin 8 (IL8) challenge, and did not affect IL8 downstream target expression. Profiling of G1 regulators revealed cyclin-dependent kinase 2 (CDK2) (Thr160) hypophosphorylation, cyclin D3 gene down-regulation, and p21 post-translational induction. However, only cyclin D3 and CDK2 contributed towards G1 arrest. Furthermore, SB265610 induced a sustained phosphorylation of the p38MAPK. Pharmacological interference with p38MAPK significantly abrogated SB265610-induced G1 arrest and normalized the expression of cyclin D3, with restoration of its exclusive binding to CDK6, but with weak recovery of CDK2 (Thr160) hypo-phosphorylation.
CONCLUSION: The present study described the mechanisms for the anti-proliferative activity of SB265610 which may be of value in IL8-rich tumor microenvironments.

Yeh CC, Fan Y, Jiang L, et al.
Genistein Suppresses Growth of Human Uterine Sarcoma Cell Lines via Multiple Mechanisms.
Anticancer Res. 2015; 35(6):3167-73 [PubMed] Related Publications
BACKGROUND: The estrogen-like soy isoflavone genistein can suppress the growth of a number of different types of cancer cells, but its effect on uterine sarcoma is unknown.
MATERIALS AND METHODS: The impact of genistein on the proliferation of three uterine sarcoma cell lines, MES-SA, MES-SA-Dx5 and SK-UT-1, was evaluated. TOPflash luciferase reporter assay and western blotting were used to assess the influence of genistein on cellular signaling; DNA fragmentation was assessed as a measure of genistein-induced apoptosis.
RESULTS: Genistein inhibited the proliferation of all three cell lines, with half-maximal inhibitory concentrations of 19.2 μM, 13.1 μM and 9.3 μM for SK-UT-1, MES-SA-Dx5, and MES-SA, respectively. This inhibitory activity was accompanied by induction of DNA fragmentation at 48 h. Western blot analyses revealed three major expression patterns: induction of p53 and Dickkopf-related protein 1 (DKK1) and suppression of histone deacetylase 4/5/7 (HDAC4/5/7), dishevelled protein (DVL), BAX, survivin and phosphorylated mitogen-activated protein kinase kinase (phospho-MEK) in all three lines; suppression of p27 and β-catenin in the more resistant lines MES-SA-Dx5 and SK-UT-1; and suppression of Protein kinase B (AKT) and extracellular signal-regulated kinases (ERKs) phosphorylation and activation of caspase-3 in the parental derived lines MES-SA and MES-SA-Dx5. Down-regulation of β-catenin expression also coincided with decreases in TOPflash activity.
CONCLUSION: Genistein reduces sarcoma cell numbers through inhibition of proliferative signaling and through induction of programmed or non-programmed cell death. Genistein-mediated signaling changes were unique in each individual cell line, and the differential signaling responses in these three cell lines may contribute to their different levels of susceptibility to this compound.

Ausawasamrit A, Itthiwarapornkul N, Chaotham C, et al.
Lupalbigenin from Derris scandens Sensitizes Detachment-induced Cell Death in Human Lung Cancer Cells.
Anticancer Res. 2015; 35(5):2827-34 [PubMed] Related Publications
BACKGROUND/AIM: The ability of cancer cells to resist to anoikis has been shown to augment cancer cell metastasis in many cancers. In search for potential substances for anti-metastatic approaches, this study aimed to investigate anoikis-sensitizing activity of lupalbigenin, extracted from Derris scandens.
MATERIALS AND METHODS: Human lung cancer cells were treated with non-cytotoxic concentrations of lupalbigenin in a detachment condition. Anoikis was evaluated at various time points using MTT viability assays. The effect of lupalbigenin on anchorage-independent growth was performed by soft-agar assay. The survival signaling proteins, as well as regulatory proteins of apoptosis and metastasis, were examined by western blot analysis.
RESULTS: Lupalbigenin treatment significantly down-regulated survival proteins, including protein kinase B (pAKT/AKT) and extracellular signal-regulated kinase (pERK/ERK), as well as anti-apoptotic protein B-cell lymphoma 2 (BCL-2), resulting in the enhancement of the cellular response to anoikis and the decrease of growth and survival in an anchorage-independent condition.
CONCLUSION: Lupalbigenin sensitizes detachment-induced cell death in human lung cancer cell through down-regulation of pro-survival proteins.

Park GB, Hur DY, Kim D
Combining CAL-101 with Celecoxib Enhances Apoptosis of EBV-transformed B-Cells Through MAPK-induced ER Stress.
Anticancer Res. 2015; 35(5):2699-708 [PubMed] Related Publications
BACKGROUND: Phosphoinositide-3 kinase (PI3K) inhibition attenuates proliferation and survival in B-cell malignancies. Celecoxib induces endoplasmic reticulum (ER) stress-induced apoptosis via a cyclo-oxgenase-2 (COX2)-independent manner in certain types of cancer cells. In the present study, we assessed the effects of combinations of drugs with a p110δ-specific inhibitor, CAL-101, and celecoxib to induce apoptosis in Epstein-Barr virus (EBV)-transformed B-cells and non-Hodgkin's lymphoma (NHL) cells.
MATERIALS AND METHODS: The apoptotic effect of combination treatment with CAL-101 and celecoxib on B-cell malignancies was determined by flow cytometry and immunoblotting.
RESULTS: Exposure to CAL-101 and celecoxib significantly increased apoptosis, which was accompanied by the inactivation of AKT, Ras homolog gene family, member A (RHOA), Rho-associated coiled-coil containing protein kinase 1 (ROCK1), and ROCK2 as well as up-regulation of Phosphatase and tensin homolog (PTEN). Co-treatment with CAL-101 and celecoxib triggered the ER stress response and the down-regulation of BCL2 and BCL-XL. SB203580, SP600125, and salubrinal effectively inhibited apoptosis and attenuated expression of phosphorylated protein kinase RNA-like endoplasmic reticulum kinase (PERK) and CCAAT-enhancer-binding protein homologous protein (CHOP). Levels of apoptosis signal-regulating kinase 1 (ASK1) were also increased after treatment with CAL-101 and celecoxib.
CONCLUSION: The apoptosis of EBV-transformed B-cells and NHL cells caused by CAL-101 and celecoxib might be related to inhibiting the RHOA/ROCK pathway and might also be associated with mitogen-activated protein kinase (MAPK)-mediated ER stress.

Andersen DS, Colombani J, Palmerini V, et al.
The Drosophila TNF receptor Grindelwald couples loss of cell polarity and neoplastic growth.
Nature. 2015; 522(7557):482-6 [PubMed] Related Publications
Disruption of epithelial polarity is a key event in the acquisition of neoplastic growth. JNK signalling is known to play an important part in driving the malignant progression of many epithelial tumours, although the link between loss of polarity and JNK signalling remains elusive. In a Drosophila genome-wide genetic screen designed to identify molecules implicated in neoplastic growth, we identified grindelwald (grnd), a gene encoding a transmembrane protein with homology to members of the tumour necrosis factor receptor (TNFR) superfamily. Here we show that Grnd mediates the pro-apoptotic functions of Eiger (Egr), the unique Drosophila TNF, and that overexpression of an active form of Grnd lacking the extracellular domain is sufficient to activate JNK signalling in vivo. Grnd also promotes the invasiveness of Ras(V12)/scrib(-/-) tumours through Egr-dependent Matrix metalloprotease-1 (Mmp1) expression. Grnd localizes to the subapical membrane domain with the cell polarity determinant Crumbs (Crb) and couples Crb-induced loss of polarity with JNK activation and neoplastic growth through physical interaction with Veli (also known as Lin-7). Therefore, Grnd represents the first example of a TNFR that integrates signals from both Egr and apical polarity determinants to induce JNK-dependent cell death or tumour growth.

Schmid CA, Robinson MD, Scheifinger NA, et al.
DUSP4 deficiency caused by promoter hypermethylation drives JNK signaling and tumor cell survival in diffuse large B cell lymphoma.
J Exp Med. 2015; 212(5):775-92 [PubMed] Article available free on PMC after 04/11/2015 Related Publications
The epigenetic dysregulation of tumor suppressor genes is an important driver of human carcinogenesis. We have combined genome-wide DNA methylation analyses and gene expression profiling after pharmacological DNA demethylation with functional screening to identify novel tumor suppressors in diffuse large B cell lymphoma (DLBCL). We find that a CpG island in the promoter of the dual-specificity phosphatase DUSP4 is aberrantly methylated in nodal and extranodal DLBCL, irrespective of ABC or GCB subtype, resulting in loss of DUSP4 expression in 75% of >200 examined cases. The DUSP4 genomic locus is further deleted in up to 13% of aggressive B cell lymphomas, and the lack of DUSP4 is a negative prognostic factor in three independent cohorts of DLBCL patients. Ectopic expression of wild-type DUSP4, but not of a phosphatase-deficient mutant, dephosphorylates c-JUN N-terminal kinase (JNK) and induces apoptosis in DLBCL cells. Pharmacological or dominant-negative JNK inhibition restricts DLBCL survival in vitro and in vivo and synergizes strongly with the Bruton's tyrosine kinase inhibitor ibrutinib. Our results indicate that DLBCL cells depend on JNK signaling for survival. This finding provides a mechanistic basis for the clinical development of JNK inhibitors in DLBCL, ideally in synthetic lethal combinations with inhibitors of chronic active B cell receptor signaling.

Shin M, Lee KE, Yang EG, et al.
PEA-15 facilitates EGFR dephosphorylation via ERK sequestration at increased ER-PM contacts in TNBC cells.
FEBS Lett. 2015; 589(9):1033-9 [PubMed] Related Publications
Phosphoprotein enriched in astrocytes of 15 kDa (PEA-15) is known to sequester extracellular signal-regulated kinase (ERK) in the cytoplasm, inhibiting tumorigenesis of human breast cancer cells. Here, we describe how PEA-15 expression affects the dephosphorylation of epidermal growth factor receptor (EGFR) through endoplasmic reticulum (ER)-plasma membrane (PM) contacts in MDA-MB-468, triple-negative breast cancer (TNBC) cells. The increased intracellular calcium concentration resulting from increased cytoplasmic phosphorylated ERK facilitates movement of ER-anchored calcium sensors to the PM. The driving force of trans-localization of calcium-dependent proteins enhances the contact between the activated EGFR and ER-localized phosphatase, PTP1B. Consequently, our findings suggest a mechanism underneath the facilitation of EGFR dephosphorylation by cytoplasmic PEA-15 expression inside TNBC cells, which may be one of the dynamic mechanisms for down-regulation of activated EGFR in cancer cells.

Liu ZM, Tseng HY, Cheng YL, et al.
TG-interacting factor transcriptionally induced by AKT/FOXO3A is a negative regulator that antagonizes arsenic trioxide-induced cancer cell apoptosis.
Toxicol Appl Pharmacol. 2015; 285(1):41-50 [PubMed] Related Publications
Arsenic trioxide (ATO) is a multi-target drug approved by the Food and Drug Administration as the first-line chemotherapeutic agent for the treatment of acute promyelocytic leukemia. In addition, several clinical trials are being conducted with arsenic-based drugs for the treatment of other hematological malignancies and solid tumors. However, ATO's modest clinical efficacy on some cancers, and potential toxic effects on humans have been reported. Determining how best to reduce these adverse effects while increasing its therapeutic efficacy is obviously a critical issue. Previously, we demonstrated that the JNK-induced complex formation of phosphorylated c-Jun and TG-interacting factor (TGIF) antagonizes ERK-induced cyclin-dependent kinase inhibitor CDKN1A (p21(WAF1/CIP1)) expression and resultant apoptosis in response to ATO in A431 cells. Surprisingly, at low-concentrations (0.1-0.2 μM), ATO increased cellular proliferation, migration and invasion, involving TGIF expression, however, at high-concentrations (5-20 μM), ATO induced cell apoptosis. Using a promoter analysis, TGIF was transcriptionally regulated by ATO at the FOXO3A binding site (-1486 to -1479bp) via the c-Src/EGFR/AKT pathway. Stable overexpression of TGIF promoted advancing the cell cycle into the S phase, and attenuated 20 μM ATO-induced apoptosis. Furthermore, blockage of the AKT pathway enhanced ATO-induced CDKN1A expression and resultant apoptosis in cancer cells, but overexpression of AKT1 inhibited CDKN1A expression. Therefore, we suggest that TGIF is transcriptionally regulated by the c-Src/EGFR/AKT pathway, which plays a role as a negative regulator in antagonizing ATO-induced CDKN1A expression and resultant apoptosis. Suppression of these antagonistic effects might be a promising therapeutic strategy toward improving clinical efficacy of ATO.

Jiang L, Zhang C, Wu Y, et al.
67kDa laminin receptor regulates the activation of MAPKs through DUSPs in glioma cell line U251.
J BUON. 2015 Jan-Feb; 20(1):253-60 [PubMed] Related Publications
PURPOSE: All-trans-retinoic-acid (ATRA), the active derivative of vitamin A, is critical in regulating cell cycle as well as inhibiting tumor growth and angiogenesis. It has been used in the clinical treatment of leukemia. 67kDa laminin receptor (67LR), as one of the receptor of laminin, plays an important role in tumor cells invasion, proliferation and metastasis. Current research indicates that 67LR is highly expressed in glioma and is associated with tumor progression. However, the underlying molecular mechanisms, especially the signaling pathways involved, have not been reported yet. Therefore it is of great importance to clarify its downstream targets.
METHODS: The U251 glioma cell line was used in this study. Cell Counting Kit-8 was used in cell proliferation assay. Quantitative real-time PCR (qRT-PCR) was used to determine the transcription level of dual specificity phosphatases (DUSPs). Western blot analysis was used to detect the expression of mitogen activated protein kinases (MAPKs) and phosphorylated MAPKs.
RESULTS: 67LR could influence the transcription of DUSPs and expression of MAPKs. ATRA could enhance the expression of 67LR in U251 cells and this enhancement was dose-dependent. ATRA was able to inhibit the growth of U251 cells.
CONCLUSIONS: ATRA expressed significant therapeutic effect on glioma cells, and 67LR is not the only factor that can influence the proliferation of U251 cells.

Kim HR, Lee HN, Lim K, et al.
15-Deoxy-Δ12,14-prostaglandin J2 induces expression of 15-hydroxyprostaglandin dehydrogenase through Elk-1 activation in human breast cancer MDA-MB-231 cells.
Mutat Res. 2014; 768:6-15 [PubMed] Related Publications
Overproduction of prostaglandin E2 (PGE2) has been reported to be implicated in carcinogenesis. The intracellular level of PGE2 is maintained not only by its biosynthesis, but also by inactivation/degradation. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is the key enzyme that catalyzes the conversion of oncogenic PGE2 to a biologically inactive keto metabolite. In the present study, we demonstrate that 15-deoxy-Δ(12,14)-prostaglandin J2 (15 d-PGJ2), one of the terminal products of cyclooxygenase-2, updregulates the expression and the activity of 15-PGDH in human breast cancer MDA-MB-231 cells. By using deletion constructs of the 15-PGDH promoter, we have found that E-twenty six (Ets) is the most essential determinant for 15-PGDH induction. 15 d-PGJ2 induced phosphorylation of Elk-1, one of Ets transcription factor family members, in the nucleus. Knockdown of Elk-1 abolished the ability of 15 d-PGJ2 to upregulate 15-PGDH expression. Furthermore, 15 d-PGJ2-mediated activation of Elk-1 was found to be dependent on activation of extracellular-signal related kinase (ERK) 1/2. Treatment of U0126, a pharmacological inhibitor of MEK1/2-ERK, abolished phosphorylation and DNA binding of Elk-1 as well as 15-PGDH induction in 15 d-PGJ2-treated MDA-MB-231 cells. Moreover, 15 d-PGJ2 generated reactive oxygen species (ROS), which contribute to the expression of 15-PGDH as well as phosphorylation of ERK1/2 and Elk-1. 15 d-PGJ2 inhibited the migration of MDA-MB-231 cells, which was attenuated by transient transfection with 15-PGDH siRNA. Taken together, these findings suggest that 15 d-PGJ2 induces the expression of 15-PGDH through ROS-mediated activation of ERK1/2 and subsequently Elk-1 in the MDA-MB-231 cells, which may contribute to tumor suppressive activity of this cyclopentenone prostaglandin.

Wang J, Xu H, Wang Q, et al.
CIAPIN1 targets Na⁺/H⁺ exchanger 1 to mediate MDA-MB-231 cells' metastasis through regulation of MMPs via ERK1/2 signaling pathway.
Exp Cell Res. 2015; 333(1):60-72 [PubMed] Related Publications
Cytokine-induced antiapoptotic inhibitor 1 (CIAPIN1) was recently identified as an essential downstream effector of the Ras signaling pathway and has been confirmed to be closely associated with various malignant tumors. However, its potential role in regulating breast cancer metastasis remains unclear. Matrix metalloproteinases (MMPs) are a broad family of zinc-biding endopeptidases that participate in the extracellular matrix (ECM) degradation that accompanies cancer cell invasion, metastasis and angiogenesis. In this study, we found up-regulation of CIAPIN1 by lentiviral expression vector inhibited the migration, invasion and MMPs expression of MDA-MB-231 cells. Further, CIAPIN1 over-expression decreased NHE1 (Na(+)/H(+) exchanger 1) expression and ERK1/2 phosphorylation. Importantly, treating CIAPIN1 over-expressed MDA-MB-231 cells with the NHE1 specific inhibitor, Cariporide, further inhibited the metastatic capacity, MMPs expression and phosphorylated ERK1/2. Treatment with the MEK1 specific inhibitor, PD98059, induced nearly the same suppression of CIAPIN1 over-expression-dependent migration, invasion and MMPs expression as was observed with Cariporide. Further, Cariporide and PD98059 synergistically suppressed migration, invasion and MMPs expression of CIAPIN1 over-expressed MDA-MB-231 cells. Thus, our results revealed the mechanism by which CIAPIN1 targeted NHE1 to mediate migration and invasion of MDA-MB-231 cells through regulation of MMPs via ERK1/2 signaling pathway.

Lee JC, Chung LC, Chen YJ, et al.
Upregulation of B-cell translocation gene 2 by epigallocatechin-3-gallate via p38 and ERK signaling blocks cell proliferation in human oral squamous cell carcinoma cells.
Cancer Lett. 2015; 360(2):310-8 [PubMed] Related Publications
Oral squamous cell carcinoma (OSCC) is a well-known malignancy that accounts for the majority of oral cancers. B-cell translocation gene 2 (BTG2) is an important regulator of cell cycle dynamics in cancer cells. However, the role of BTG2 in OSCC cells and the influences of epigallocatechin-3-gallate (EGCG) on BTG2 gene expressions have not been well evaluated. The objectives of this study were to examine the effect of EGCG-induced BTG2 expression and the potential signal pathways involved. The (3)H-thymidine incorporation and Western-blot assays revealed cell proliferation was attenuated by EGCG via upregulation of BTG2 expression causing cell cycle G1 phase arrest in OSCC cells. BTG2 overexpression decreased tumor cell growth, while BTG2 knockdown illuminated the opposite effect in xenograft animal studies. Overexpressed BTG2 arrested the cell cycle at the G1 phase and downregulated protein expressions of cyclin A, cyclin D, and cyclin E. Western-blot assays indicated that EGCG induced phosphorylation of p38, JNK, and ERK. However, pretreatments with selective mitogen-activated protein kinase (MAPK) inhibitors, SB203580 (p38 inhibitor) and PD0325901 (ERK1/2 inhibitor), significantly suppressed the activation of EGCG on BTG2 expression. Our results indicate that EGCG attenuates cell proliferation of OSCC cells by upregulating BTG2 expression via p38 and ERK pathways.

Drasin DJ, Guarnieri AL, Neelakantan D, et al.
TWIST1-Induced miR-424 Reversibly Drives Mesenchymal Programming while Inhibiting Tumor Initiation.
Cancer Res. 2015; 75(9):1908-21 [PubMed] Article available free on PMC after 01/05/2016 Related Publications
Epithelial-to-mesenchymal transition (EMT) is a dynamic process that relies on cellular plasticity. Recently, the process of an oncogenic EMT, followed by a reverse mesenchymal-to-epithelial transition (MET), has been implicated as critical in the metastatic colonization of carcinomas. Unlike governance of epithelial programming, regulation of mesenchymal programming is not well understood in EMT. Here, we describe and characterize the first microRNA that enhances exclusively mesenchymal programming. We demonstrate that miR-424 is upregulated early during a TWIST1 or SNAI1-induced EMT, and that it causes cells to express mesenchymal genes without affecting epithelial genes, resulting in a mixed/intermediate EMT. Furthermore, miR-424 increases motility, decreases adhesion, and induces a growth arrest, changes associated with a complete EMT that can be reversed when miR-424 expression is lowered, concomitant with an MET-like process. Breast cancer patient miR-424 levels positively associate with TWIST1/2 and EMT-like gene signatures, and miR-424 is increased in primary tumors versus matched normal breast. However, miR-424 is downregulated in patient metastases versus matched primary tumors. Correspondingly, miR-424 decreases tumor initiation and is posttranscriptionally downregulated in macrometastases in mice, suggesting the need for biphasic expression of miR-424 to transit the EMT-MET axis. Next-generation RNA sequencing revealed miR-424 regulates numerous EMT and cancer stemness-associated genes, including TGFBR3, whose downregulation promotes mesenchymal phenotypes, but not tumor-initiating phenotypes. Instead, we demonstrate that increased MAPK-ERK signaling is critical for miR-424-mediated decreases in tumor-initiating phenotypes. These findings suggest miR-424 plays distinct roles in tumor progression, potentially facilitating earlier, but repressing later, stages of metastasis by regulating an EMT-MET axis.

Lourenco S, Teixeira VH, Kalber T, et al.
Macrophage migration inhibitory factor-CXCR4 is the dominant chemotactic axis in human mesenchymal stem cell recruitment to tumors.
J Immunol. 2015; 194(7):3463-74 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
Mesenchymal stromal cells (MSCs) are inherently tumor homing and can be isolated, expanded, and transduced, making them viable candidates for cell therapy. This tumor tropism has been used to deliver anticancer therapies to various tumor models. In this study, we sought to discover which molecules are the key effectors of human MSC tumor homing in vitro and using an in vivo murine model. In this study, we discover a novel role for macrophage migration inhibitory factor (MIF) as the key director of MSC migration and infiltration toward tumor cells. We have shown this major role for MIF using in vitro migration and invasion assays, in presence of different receptor inhibitors and achieving a drastic decrease in both processes using MIF inhibitor. Additionally, we demonstrate physical interaction between MIF and three receptors: CXCR2, CXCR4, and CD74. CXCR4 is the dominant receptor used by MIF in the homing tumor context, although some signaling is observed through CXCR2. We demonstrate downstream activation of the MAPK pathway necessary for tumor homing. Importantly, we show that knockdown of either CXCR4 or MIF abrogates MSC homing to tumors in an in vivo pulmonary metastasis model, confirming the in vitro two-dimensional and three-dimensional assays. This improved understanding of MSC tumor tropism will further enable development of novel cellular therapies for cancers.

Stachler MD, Rinehart E, Lindeman N, et al.
Novel molecular insights from routine genotyping of colorectal carcinomas.
Hum Pathol. 2015; 46(4):507-13 [PubMed] Related Publications
Routine tumor genotyping enables identification of concurrent mutations in tumors and reveals low-frequency mutations that may be associated with a particular tumor phenotype. We genotyped 311 colorectal carcinomas (CRCs) for 471 mutation hot spots in 41 cancer-associated genes. At least 1 mutation was present in 239 (77%) of 311 tumors. Two concurrent mutations were identified in 89 (29%) tumors, 3 mutations in 24 (8%), 4 mutations in 6 (2%), and 5 mutations in 1 tumor. KRAS mutations were most frequent and identified in 132 (42%) tumors, followed by APC in 79 (25%) and TP53 in 64 (21%) tumors. Mutations in PIK3CA, BRAF, CTNNB1, and NRAS were identified in 41, 27, 11, and 9 cases, respectively. Rare mutations not typically associated with CRC included AKT1 (4), AKT2 (1), IDH1 (1), KIT (1), MAP2K1 (1), PTEN (2), and GNAS (6). GNAS mutations in CRC correlated with a mucinous phenotype and were present in 20% of all mucinous adenocarcinomas evaluated in this study. Among CRCs with a PIK3CA mutation, 77% showed concurrent mutations in other cancer-associated genes, and 4% of CRC did not neatly fit into either the chromosomal instability pathway or CpG island methylator phenotype/microsatellite instability pathway, suggesting overlapping mutational profile in some tumors. Our findings indicate that routine tumor genotyping is helpful in identifying low-frequency mutations, such as GNAS, that may correlate with a specific morphological phenotype and also reveal multiplicity of concurrent mutations in a significant proportion of CRC that may have significant implications for clinical trial design and personalized therapy.

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.

Eke I, Zscheppang K, Dickreuter E, et al.
Simultaneous β1 integrin-EGFR targeting and radiosensitization of human head and neck cancer.
J Natl Cancer Inst. 2015; 107(2) [PubMed] Related Publications
BACKGROUND: Signaling from integrins and receptor tyrosine kinases (RTKs) contributes substantially to therapy resistance of malignant tumors. We investigated simultaneous β1 integrin-epidermal growth factor receptor (EGFR) targeting plus radiotherapy in human head and neck squamous cell carcinomas (HNSCCs).
METHODS: Ten HNSCC cell lines were grown in three-dimensional laminin-rich extracellular matrix cell cultures and two of them as tumor xenografts in nude mice (n = 12-16 per group). Targeting of β1 integrin and EGFR with monoclonal inhibitory antibodies (AIIB2 and cetuximab, respectively) was combined with x-ray irradiation. Clonogenic survival, tumor growth, and tumor control (evaluated by Kaplan-Meier analysis), apoptosis, phosphoproteome (interactome, network betweeness centrality analysis), receptor expression (immunohistochemistry), and downstream signaling (western blotting) were assessed. Various mutants of the integrin signaling mediator focal adhesion kinase (FAK) were employed for mechanistic studies. All statistical tests were two-sided.
RESULTS: Compared with β1 integrin or EGFR single inhibition, combined β1 integrin-EGFR targeting resulted in enhanced cytotoxicity and radiosensitization in eight out of 10 tested HNSCC cell lines, which responded with an FAK dephosphorylation after β1 integrin inhibition. In vivo, simultaneous anti-β1 integrin/anti-EGFR treatment and radiotherapy of UTSCC15 responder xenografts enabled better tumor control compared with anti-EGFR monotherapy and irradiation (hazard ratio [HR] = 6.9, 95% confidence interval [CI] = 1.6 to 30.9, P = .01), in contrast to the SAS nonresponder tumor model (HR = 0.9, 95% CI = 0.4 to 2.3, P = .83). Mechanistically, a protein complex consisting of FAK- and Erk1-mediated prosurvival signals for radiation resistance, which was effectively compromised by β1 integrin and EGFR blocking.
CONCLUSIONS: Concomitant targeting of β1 integrin and EGFR seems a powerful and promising approach to overcome radioresistance of HNSCCs.

Mansour MA, Hyodo T, Ito S, et al.
SATB2 suppresses the progression of colorectal cancer cells via inactivation of MEK5/ERK5 signaling.
FEBS J. 2015; 282(8):1394-405 [PubMed] Related Publications
Special AT-rich sequence binding protein 2 (SATB2) is an evolutionarily conserved transcription factor that has multiple roles in neuronal development, osteoblast differentiation, and craniofacial patterning. SATB2 binds to the nuclear matrix attachment region, and regulates the expression of diverse sets of genes by altering chromatin structure. Recent studies have reported that high expression of SATB2 is associated with favorable prognosis in colorectal and laryngeal cancer; however, it remains uncertain whether SATB2 has tumor-suppressive functions in cancer cells. In this study, we examined the effects of SATB2 expression on the malignant characteristics of colorectal cancer cells. Expression of SATB2 repressed the proliferation of cancer cells in vitro and in vivo, and also suppressed their migration and invasion. Extracellular signal-regulated kinase 5 (ERK5) is a mitogen-activated protein kinase that is associated with an aggressive phenotype in various types of cancer. SATB2 expression reduced the activity of ERK5, and constitutive activation of ERK5 restored the proliferation, anchorage-independent growth, migration and invasion of SATB2-expressing cells. Our results demonstrate the existence of a novel regulatory mechanism of SATB2-mediated tumor suppression via ERK5 inactivation.

Zhang B, Gu Y
Bortezomib inhibits gastric carcinoma HGC-27 cells through the phospho-Jun N-terminal kinase (p-JNK) pathway in vitro.
Gene. 2015; 559(2):164-71 [PubMed] Related Publications
The study is designed to explore the anticancer mechanism of Bortezomib. The effects of Bortezomib on the proliferation of human gastric cancer cells HGC-27 and expression levels of the phospho-Jun N-terminal kinase (p-JNK) pathway-related proteins in vitro were investigated. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that the Bortezomib significantly decreased the viability of HGC-27 cells and induced apoptosis. Western blot showed that the Bortezomib strongly increased the levels of p-JNK, caspase-3, PARP, and bax proteins while it increased the level of bcl-2. However, SP600125 can significantly decrease antitumour effects of Bortezomib in HGC-27 cells. It can be concluded that Bortezomib has significant inhibitory effects on the growth of HGC-27 cells. The effect may be achieved partly via upregulating JNK pathway and its down-stream apoptosis-related proteins. Therefore, Bortezomib may be beneficial in gastric carcinoma treatment.

Nam EH, Lee Y, Moon B, et al.
Twist1 and AP-1 cooperatively upregulate integrin α5 expression to induce invasion and the epithelial-mesenchymal transition.
Carcinogenesis. 2015; 36(3):327-37 [PubMed] Related Publications
Epithelial-mesenchymal transition (EMT) is an important process implicated in tumor invasion and metastasis. Twist1 is a transcription factor that induces EMT, including E-cadherin suppression and cancer cell migration and invasion; hence it promotes cancer metastasis. Twist1 directly or indirectly regulates the expression of various genes and cellular functions involved in cancer progression. However, the underlying mechanisms remain largely unknown. In this study, we investigated the molecular basis for Twist1-mediated invasion and EMT. In human cancer cells, Twist1 was found to directly upregulate transcription of the mesenchymal gene integrin α5 in an E-box-independent, but activating protein-1 (AP-1) element-dependent, manner. Twist1 activated the integrin α5 promoter by interacting with and activating the transcription factor AP-1, composed of c-Jun and activating transcription factor-2 (ATF-2); it also enhanced the nuclear presence of ATF-2. AP-1 was critical for Twist1-induced cancer cell invasion, primarily through the induction of integrin α5, which activated c-Jun N-terminal kinase and focal adhesion kinase-signaling activities. Using data from The Cancer Genome Atlas, we found that Twist1 expression positively correlates with integrin α5 expression in human colorectal cancers. These findings suggest that cooperation between Twist1 and AP-1 represents a novel mechanism for EMT and tumor invasiveness. This study supports further investigation into the molecular basis underlying the diverse Twist1-mediated functions that occur during tumor progression.

Abdel-Latif MM, Kelleher D, Reynolds JV
Molecular mechanisms of constitutive and inducible NF-kappaB activation in oesophageal adenocarcinoma.
Eur J Cancer. 2015; 51(4):464-72 [PubMed] Related Publications
BACKGROUND: Nuclear factor-kappaB (NF-κB) regulates the expression of a large number of genes involved in the immune and inflammatory response. NF-κB is constitutively activated in oesophageal tumour tissues and induced in oesophageal cells by bile and acid. The aim of the present study was to define the mechanisms underlying NF-κB activation in oesophageal adenocarcinoma.
PATIENTS AND METHODS: Fresh biopsy specimens were obtained from 20 patients with oesophageal adenocarcinoma. The activation of NF-κB in oesophageal tumour specimens and oesophageal SKGT-4 cells was assessed by gel mobility shift and Western blotting. Phosphorylation of protein kinase B (AKT/PKB), Ikappa kinase-alpha/beta (IKK-α/β) and extracellular signal-regulated kinase 1/2 (ERK1/2) was examined by Western blotting. High content analysis was used to quantify NF-κB translocation in oesophageal cells.
RESULTS: Oesophageal tumour tissues had higher levels of NF-κB. Increased levels of phosphorylated AKT and IKK-α/β and ERK1/2 were detected in tumour tissues compared with normal oesophageal mucosa. Exposure of SKGT-4 cells to deoxycholic acid (DCA) or acid resulted in NF-κB activation and phosphorylation of AKT, IKK-α/β and ERK1/2. Specific inhibitors for phosphoinositide 3-kinase; PI3K (LY294002 and worhmannin) and ERK1/2 inhibitors (PD98059 and U0126) suppressed DCA- and acid-induced NF-κB activation. The proteasome inhibitor MG-132 and the antioxidants vitamin C and pyrrolidine dithiocarbamate (PDTC) also inhibited NF-κB activation.
CONCLUSIONS: Our data demonstrate a major role for PI3K/AKT-IKK-α/β-ERK1/2 signalling pathway in NF-κB activation in oesophageal adenocarcinoma. These results suggest that NF-κB may be a prognostic marker for oesophageal adenocarcinoma, and modulating of NF-κB may uncover new therapeutic strategies.

Della Pepa C, Tonini G, Santini D, et al.
Low Grade Serous Ovarian Carcinoma: from the molecular characterization to the best therapeutic strategy.
Cancer Treat Rev. 2015; 41(2):136-43 [PubMed] Related Publications
Low Grade Serous Ovarian Carcinoma, LGSOC, is certainly a rare disease, accounting for only a small proportion of all ovarian carcinomas, nevertheless in the last decade we have acquired many data about its molecular and clinical features and it has been largely accepted that it has distinct pathogenesis, genetic aberrations and clinical behavior compared to High Grade Serous Ovarian Carcinoma, HGSOC, which is the most common ovarian cancer histotype. A large number of series pointed out the high rate of KRAS and BRAF mutations in LGSOCs and Serous Borderline Tumors, SBLTs, in contrast with their rarity in HGSOC. Such finding, together with the recurrent observation of focus of LGSOC associated with areas of SBLT in the same lesion, led to abandon the traditional histology classification, defining three types of serous carcinomas, in favor of a new dualistic grading system which recognizes only LG and HG carcinomas corresponding to distinct tumorigenesis pathways, the former based on KRAS/BRAF mutations and alteration of the MAP/ERK signaling, the latter characterized by early genetic instability and wild type status of KRAS and BRAF. LGSOC shows favorable overall survival, compared to general ovarian cancer population, but worrying resistance to conventional treatments. MEK inhibitors are emerging as active agents and may well represent an effective therapeutic strategy in the near future.

Zhao D, Lu Y, Yang C, et al.
Activation of FGF receptor signaling promotes invasion of non-small-cell lung cancer.
Tumour Biol. 2015; 36(5):3637-42 [PubMed] Related Publications
The molecular regulation of metastasis of non-small-cell lung cancer (NSCLC) remains not completely defined. Here we showed significant higher MMP26 in the resected NSCLC than adjacent healthy tissue from the patients. Moreover, a strong correlation between MMP26 and the phosphorylated fibroblast growth factor receptor 1 (FGFR1) was detected. To examine the causal relationship between activated FGFR signaling and MMP26, we studied a human NSCLC cell line, A549. We found that FGF1-induced FGFR1 phosphorylation in A549 cells activated MMP26, resulting in an increase in cancer invasiveness. Inhibition of FGFR1 phosphorylation abolished FGF1-stimulated MMP26 activation, suggesting that activation of FGFR signaling pathway in NSCLC promotes cancer metastasis through MMP26. To define the signal transduction cascades downstream of FGFR1 activation for MMP26 activation, we used specific inhibitors for PI3K, ERK/MAPK, and JNK, respectively, to the FGF1-stimulated A549 cells. We found that only inhibition of JNK significantly decreased the activation of MMP26 in response to FGF1 stimulation, suggesting that activation of FGFR1 signaling may activate JNK to activate MMP26 in NSCLC. Our study thus highlights FGFR signaling pathway and MMP26 as novel therapeutic targets for NSCLC therapy.

Boye A, Kan H, Wu C, et al.
MAPK inhibitors differently modulate TGF-β/Smad signaling in HepG2 cells.
Tumour Biol. 2015; 36(5):3643-51 [PubMed] Related Publications
The aim of this study was to investigate the mitogen-activated protein kinase (MAPK) pathway, which crosstalk with TGF-β/Smad signaling via linker phosphorylation of Smad2/3 to promote hepatocarcinogenesis. After DEN-induced hepatocellular carcinoma (HCC) in rats showed increased phosphorylation of JNK1/2, p38, and ERK1/2, we next antagonized TGF-β1-induced phosphorylation of JNK1/2, p38, ERK1/2, Smad2/3 signaling in HepG2 cells using SP600125, SB203580, and PD98059, respectively. Cell proliferation and invasion were assessed by MTT assay and transwell invasion chambers, respectively. Smad2/3, Smad4, and Smad7 expressions and PAI-1 messenger RNA (mRNA) transcription were measured by using immuno-precipitation/immuno-blotting and real-time RT-PCR, respectively. All the MAPK-specific inhibitors suppressed cell invasion, while all but PD98059 suppressed cell proliferation. Both SP600125 and SB203580 blocked pSmad2C/L and oncogenic pSmad3L. PD98059 blocked pSmad2L but had no effect on elevated pSmad2C and oncogenic pSmad3L. All but PD98059 blocked Smad2/3/4 complex formation and restored Smad7 expression, while all the three MAPK-Specific inhibitors repressed PAI-1 mRNA transcription. Both SP600125 and SB203580 inhibited HepG2 cells' proliferation and invasion by blocking oncogenic pSmad3L and Smad2/3/4 complex formation. PD98059 repressed PAI-1 mRNA by an unknown mechanism.

Huang HL, Chiang WL, Hsiao PC, et al.
Timosaponin AIII mediates caspase activation and induces apoptosis through JNK1/2 pathway in human promyelocytic leukemia cells.
Tumour Biol. 2015; 36(5):3489-97 [PubMed] Related Publications
Timosaponin AIII (TAIII) is a steroidal saponin isolated from Anemarrhena asphodeloides that has been shown to inhibit cell growth and induce apoptosis in cancer. However, the effect of TAIII on acute myeloid leukemia (AML) remains unclear. Here, the molecular mechanism by which TAIII-induced apoptosis affects human AML cells was investigated. The results showed that TAIII significantly inhibited cell proliferation of four AML cell lines (MV4-11, U937, THP-1, and HL-60). Furthermore, TAIII induced apoptosis of HL-60 cells through caspase-3, caspase-8, and caspase-9 activations and PARP cleavage in a dose- and time-dependent manner. Moreover, Western blot analysis also showed that TAIII increased phosphorylation of JNK1/2 and p38 MAPK in a dose-dependent manner. Inhibition of JNK1/2 by specific inhibitors significantly abolished the TAIII-induced activation of the caspase-8. Taken together, our results suggest that TAIII induces HL-60 cell apoptosis through JNK1/2 pathways and could serve as a potential additional chemotherapeutic agent for treating AML.

Shen AS, Peterhof E, Kind P, et al.
Activating mutations in the RAS/mitogen-activated protein kinase signaling pathway in sporadic trichoblastoma and syringocystadenoma papilliferum.
Hum Pathol. 2015; 46(2):272-6 [PubMed] Related Publications
Trichoblastoma (TB) and syringocystadenoma papilliferum (SCAP) are both rare adnexal skin lesions occurring either sporadically or as secondary neoplasms in sebaceous nevi. TB and SCAP associated with sebaceous nevi have been shown to carry the same HRAS mutation as the underlying nevus. However, the genetic background of sporadic TB and SCAP has remained unknown. Therefore, we screened 18 sporadic TBs and 23 sporadic syringocystadenoma papillifera from 41 patients for the presence of activating mutations in RAS genes and other oncogenes. Using a RAS SNaPshot assay, HRAS mutations were detected in 2 (11%) of 18 sporadic TB and 6 (26%) of 23 sporadic syringocystadenoma papillifera. A KRAS mutation was identified in 1 sporadic SCAP. High-throughput oncogene mutation profiling furthermore identified BRAF V600E mutations in sporadic syringocystadenoma papillifera, which could be validated in 12 (52%) of 23 lesions using a BRAF SNaPshot assay. BRAF and RAS mutations were mutually exclusive in sporadic syringocystadenoma papillifera. No BRAF mutation could be detected in 3 syringocystadenoma papillifera secondarily arisen from a sebaceous nevus as well as in sporadic TB. In 14 lesions carrying an oncogenic mutation, nonlesional control tissue from the epidermal margin revealed a wild-type sequence, thus proving the somatic character of the mutation. Our results indicate that activation of the RAS-mitogen-activated protein kinase pathway by BRAF and RAS mutations contributes significantly to the tumorigenesis of sporadic SCAP and, less frequently, of sporadic TB.

Thaler S, Thiede G, Hengstler JG, et al.
The proteasome inhibitor Bortezomib (Velcade) as potential inhibitor of estrogen receptor-positive breast cancer.
Int J Cancer. 2015; 137(3):686-97 [PubMed] Related Publications
Around 70% of breast cancers express the estrogen receptor α (ERα) and depend on estrogen for growth, survival and disease progression. The presence of hormone sensitivity is usually associated with a favorable prognosis. Use of adjuvant anti-endocrine therapy has significantly decreased breast cancer mortality in patients with early-stage disease, and anti-endocrine therapy also plays a central role in the treatment of advanced stages. However a subset of hormone receptor-positive breast cancers do not benefit from anti-endocrine therapy, and nearly all hormone receptor-positive metastatic breast cancers ultimately develop resistance to anti-hormonal therapies. Despite new insights into mechanisms of anti-endocrine therapy resistance, e.g., crosstalk between ERα and Her2/neu, the management of advanced hormone-receptor-positive breast cancers that are resistant to anti-endocrine agents remains a significant challenge. In the present study, we demonstrate that the proteasome inhibitor Bortezomib strongly inhibits ERα and HER2/neu expression, increases expression of cyclin-dependent kinase inhibitors, inhibits expression of multiple genes associated with poor prognosis in ERα+ breast cancer patients and induces cell death in ER+ breast cancer cells in both the presence and absence of functional p53. Although Bortezomib increased the levels of p53 and increased the expression of pro-apoptotic target genes in ERα+ breast cancer cells harboring wild-type p53, Bortezomib also exerts anti-tumoral effects on ERα+ breast cancer cells through suppression of ERα expression and inhibition of PI3K/Akt/mammalian target of rapamycin (mTOR) and ERK signaling independently of functional p53. These findings suggest that Bortezomib might have the potential to improve the management of anti-endocrine therapy resistant ERα+ breast cancers independently of their p53 status.

Kim EJ, Kim SO, Jin X, et al.
Epidermal growth factor receptor variant III renders glioma cancer cells less differentiated by JAGGED1.
Tumour Biol. 2015; 36(4):2921-8 [PubMed] Related Publications
Glioblastoma is a highly aggressive primary brain tumor in which the majority of cancer cells are undifferentiated. One of the most common oncogenic drivers for this malignancy is the epidermal growth factor receptor variant III (EGFRvIII), which lacks a portion of the extracellular ligand-binding domain due to deletion of exons 2-7 of the EGFR gene. EGFRvIII plays a critical role in tumor progression, promoting acquisition of stem cell-like features including an undifferentiated state and therapy resistance. However, the molecular mechanisms by which EGFRvIII contributes to cancer cell aggressiveness remain poorly understood. Here, we show that EGFR expression correlates with JAGGED1 expression in glioblastoma patients. Overexpression of EGFRvIII in glioma cell lines augmented JAGGED1 expression at the transcriptional level through the mitogen-activated protein kinase signaling pathway. Consequently, EGFRvIII overexpression drove partial dedifferentiation of glioma cells, as determined by tumorsphere-forming ability and expression of stem cell markers, through JAGGED1 induction. EGFRvIII-mediated radioresistance, but not chemoresistance, was also modulated by JAGGED1. Taken together, our results provide new insight into the mechanism underlying EGFRvIII-driven glioblastoma aggressiveness.

Aissaoui H, Prévost C, Boucharaba A, et al.
MDA-9/syntenin is essential for factor VIIa-induced signaling, migration, and metastasis in melanoma cells.
J Biol Chem. 2015; 290(6):3333-48 [PubMed] Article available free on PMC after 06/02/2016 Related Publications
Melanoma differentiation associated gene-9 (MDA-9), also known as syntenin, is a novel gene that positively regulates cancer cell motility, invasion, and metastasis through distinct biochemical and signaling pathways, but how MDA-9/syntenin is regulated in response to signals with the extracellular environment and promotes tumor progression is unclear. We now demonstrate that MDA-9/syntenin is dramatically up-regulated by a combination of rFVIIa and factor F(X) in malignant melanoma. Induction of MDA-9/syntenin in melanoma was found to occur in a thrombin-independent signaling pathway and involves the PAR-1/c-Src/Rho GTPases Rac1 and Cdc42/c-Jun N-terminal kinase axis resulting in the activation of paxillin, NF-κB, and matrix metalloproteinase-2 (MMP-2). MDA-9/syntenin physically interacts with c-Src through its PDZ binding motif following stimulation of melanoma cells with rFVIIa and FX. We also document that induction of this signaling pathway is required for TF·FVIIa·Xa-induced cell migration, invasion, and metastasis by melanoma cells. The present finding uncovers a novel role of MDA-9/syntenin as an important TF·FVIIa·Xa/PAR-1-regulated gene that initiates a signaling circuit essential for cell motility and invasion of metastatic melanoma. In these contexts, targeting TF·FVIIa·Xa and its relevant downstream targets such as MDA-9/syntenin, may represent a novel therapeutic strategy to control the evolution of neoplastic cells.

Peng F, Zhang H, Du Y, Tan P
miR-23a promotes cisplatin chemoresistance and protects against cisplatin-induced apoptosis in tongue squamous cell carcinoma cells through Twist.
Oncol Rep. 2015; 33(2):942-50 [PubMed] Related Publications
Tongue squamous cell carcinoma (TSCC) is one of the most common head and neck cancers. Cisplatin is effective as a single agent or in combination with other drugs for the treatment of TSCC. Treatment with cisplatin-based chemotherapy has been found to improve the prognosis of patients with TSCC. However, one of the most important clinical issues of cisplatin-based TSCC chemotherapy is the intrinsic/acquired chemoresistance to cisplatin. Increased expression of miR-23a reportedly promotes cisplatin chemoresistance in TSCC cells. High expression of Twist is also associated with cancer chemoresistance and poor prognosis of TSCC patients. In the present study, we explored the interaction between miR-23a and Twist in TSCC cells, and assessed its impact on TSCC chemoresistance to cisplatin. miR-23a and/or Twist were overexpressed or knocked down in SCC-4 and Tca8113 human TSCC cells. The expression levels of miR-23a and Twist were determined. The half maximal inhibitory concentration (IC50) of cisplatin and cell apoptosis rate under cisplatin treatment were used as measures of cisplatin chemoresistance. Overexpression of miR-23a in both SCC-4 and Tca8113 cells markedly increased Twist expression, c-Jun N-terminal kinase (JNK) activity and the half maximal inhibitory concentration (IC50) of cisplain, and decreased cisplatin-induced apoptosis, all of which was abolished by knockdown of Twist or selective JNK inhibitor SP600125. On the other hand, knockdown of miR-23a significantly decreased Twist expression, JNK activity and IC50 of cisplain, and increased cisplatin-induced apoptosis, all of which was completely reversed by overexpression of Twist. In conclusion, the present study for the first time demonstrates that miR-23a promotes cisplatin chemoresistance and protects cisplatin-induced apoptosis in TSCC cells through inducing Twist expression by a JNK-dependent mechanism. It adds new insights into the molecular mechanisms underlying TSCC chemoresistance.

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