EP300

Gene Summary

Gene:EP300; E1A binding protein p300
Aliases: p300, KAT3B, RSTS2
Location:22q13.2
Summary:This gene encodes the adenovirus E1A-associated cellular p300 transcriptional co-activator protein. It functions as histone acetyltransferase that regulates transcription via chromatin remodeling and is important in the processes of cell proliferation and differentiation. It mediates cAMP-gene regulation by binding specifically to phosphorylated CREB protein. This gene has also been identified as a co-activator of HIF1A (hypoxia-inducible factor 1 alpha), and thus plays a role in the stimulation of hypoxia-induced genes such as VEGF. Defects in this gene are a cause of Rubinstein-Taybi syndrome and may also play a role in epithelial cancer. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:histone acetyltransferase p300
Source:NCBIAccessed: 13 March, 2017

Ontology:

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 (1992-2017)
Graph generated 13 March 2017 using data from PubMed using criteria.

Literature Analysis

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

Tag cloud generated 13 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

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

Entity Topic PubMed Papers
Rubinstein-Taybi SyndromeEP300 mutation in Rubinstein-Taybi Syndrome
Rubinstein-Taybi Syndrome is an autosomal dominant chromosomal disorder characterized by mental retardation, broad thumbs, and webbing of fingers and toes. Individuals with RTS have an increased risk of brain tumors and certain other cancers.
View Publications34
Breast CancerEP300 and Breast Cancer View Publications25
Lung CancerEP300 and Lung Cancer View Publications15
Ovarian CancerEP300 and Ovarian Cancer View Publications8
Esophageal CancerEP300 and Esophageal CancerPrognostic View Publications5
Stomach CancerEP300 and Stomach Cancer View Publications3

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

Latest Publications: EP300 (cancer-related)

Wang P, Ye JA, Hou CX, et al.
Combination of lentivirus-mediated silencing of PPM1D and temozolomide chemotherapy eradicates malignant glioma through cell apoptosis and cell cycle arrest.
Oncol Rep. 2016; 36(5):2544-2552 [PubMed] Free Access to Full Article Related Publications
Temozolomide (TMZ) is approved for use as first-line treatment for glioblastoma multiforme (GBM). However, GBM shows chemoresistance shortly after the initiation of treatment. In order to detect whether silencing of human protein phosphatase 1D magnesium dependent (PPM1D) gene could increase the effects of TMZ in glioma cells, glioma cells U87-MG were infected with lentiviral shRNA vector targeting PPM1D silencing. After PPM1D silencing was established, cells were treated with TMZ. The multiple functions of human glioma cells after PPM1D silencing and TMZ chemotherapy were detected by flow cytometry and MTT assay. Significantly differentially expressed genes were distinguished by microarray-based gene expression profiling and analyzed by gene pathway enrichment analysis and ontology assessment. Western blotting was used to establish the protein expression of the core genes. PPM1D gene silencing improves TMZ induced cell proliferation and induces cell apoptosis and cell cycle arrest. When PPM1D gene silencing combined with TMZ was performed in glioma cells, 367 genes were upregulated and 444 genes were downregulated compared with negative control. The most significant differential expression pathway was pathway in cancer and IGFR1R, PIK3R1, MAPK8 and EP300 are core genes in the network. Western blotting showed that MAPK8 and PIK3R1 protein expression levels were upregulated and RB1 protein expression was decreased. It was consistent with that detected in gene expression profiling. In conclusion, PPM1D gene silencing combined with TMZ eradicates glioma cells through cell apoptosis and cell cycle arrest. PIK3R1/AKT pathway plays a role in the multiple functions of glioma cells after PPM1D silencing and TMZ chemotherapy.

Liu YF, Wang BY, Zhang WN, et al.
Genomic Profiling of Adult and Pediatric B-cell Acute Lymphoblastic Leukemia.
EBioMedicine. 2016; 8:173-83 [PubMed] Free Access to Full Article Related Publications
Genomic landscapes of 92 adult and 111 pediatric patients with B-cell acute lymphoblastic leukemia (B-ALL) were investigated using next-generation sequencing and copy number alteration analysis. Recurrent gene mutations and fusions were tested in an additional 87 adult and 93 pediatric patients. Among the 29 newly identified in-frame gene fusions, those involving MEF2D and ZNF384 were clinically relevant and were demonstrated to perturb B-cell differentiation, with EP300-ZNF384 inducing leukemia in mice. Eight gene expression subgroups associated with characteristic genetic abnormalities were identified, including leukemia with MEF2D and ZNF384 fusions in two distinct clusters. In subgroup G4 which was characterized by ERG deletion, DUX4-IGH fusion was detected in most cases. This comprehensive dataset allowed us to compare the features of molecular pathogenesis between adult and pediatric B-ALL and to identify signatures possibly related to the inferior outcome of adults to that of children. We found that, besides the known discrepancies in frequencies of prognostic markers, adult patients had more cooperative mutations and greater enrichment for alterations of epigenetic modifiers and genes linked to B-cell development, suggesting difference in the target cells of transformation between adult and pediatric patients and may explain in part the disparity in their responses to treatment.

Dagdemir A, Judes G, Lebert A, et al.
Epigenetic Modifications with DZNep, NaBu and SAHA in Luminal and Mesenchymal-like Breast Cancer Subtype Cells.
Cancer Genomics Proteomics. 2016 Jul-Aug; 13(4):291-303 [PubMed] Related Publications
BACKGROUND/AIM: Numerous studies have shown that breast cancer and epigenetic mechanisms have a very powerful interactive relation. The MCF7 cell line, representative of luminal subtype and the MDA-MB 231 cell line representative of mesenchymal-like subtype were treated respectively with a Histone Methyl Transferase Inhibitors (HMTi), 3-Deazaneplanocin hydrochloride (DZNep), two histone deacetylase inhibitors (HDACi), sodium butyrate (NaBu), and suberoylanilide hydroxamic acid (SAHA) for 48 h.
MATERIALS AND METHODS: Chromatin immunoprecipitation (ChIP) was used to observe HDACis (SAHA and NaBu) and HMTi (DZNep) impact on histones and more specifically on H3K27me3, H3K9ac and H3K4ac marks with Q-PCR analysis of BRCA1, SRC3 and P300 genes. Furthermore, the HDACi and HMTi effects on mRNA and protein expression of BRCA1, SRC3 and P300 genes were checked. In addition, statistical analyses were used.
RESULTS: In the MCF7 luminal subtype with positive ER, H3k4ac was significantly increased on BRCA1 with SAHA. On the contrary, in the MDA-MB 231 breast cancer cell line, representative of mesenchymal-like subtype with negative estrogen receptor, HDACis had no effect. Also, DZNEP decreased significantly H3K27me3 on BRCA1 in MDA-MB 231. Besides, on SRC3, a significant increase for H3K4ac was obtained in MCF7 treated with SAHA. And DZNEP had no effect in MCF7. Also, in MDA-MB 231 treated with DZNEP, H3K27me3 significantly decreased on SRC3 while H3K4ac was significantly increased in MDA-MB-231 treated with SAHA or NaBu for P300.
CONCLUSION: Luminal and mesenchymal-like breast cancer subtype cell lines seemed to act differently to HDACis (SAHA and NaBu) or HMTi (DZNEP) treatments.

Deb P, Bhan A, Hussain I, et al.
Endocrine disrupting chemical, bisphenol-A, induces breast cancer associated gene HOXB9 expression in vitro and in vivo.
Gene. 2016; 590(2):234-43 [PubMed] Article available free on PMC after 30/09/2017 Related Publications
HOXB9 is a homeobox-containing gene that plays a key role in mammary gland development and is associated with breast and other types of cancer. Here, we demonstrate that HOXB9 expression is transcriptionally regulated by estradiol (E2), in vitro and in vivo. We also demonstrate that the endocrine disrupting chemical bisphenol-A (BPA) induces HOXB9 expression in cultured human breast cancer cells (MCF7) as well as in vivo in the mammary glands of ovariectomized (OVX) rats. Luciferase assay showed that estrogen-response-elements (EREs) in the HOXB9 promoter are required for BPA-induced expression. Estrogen-receptors (ERs) and ER-co-regulators such as MLL-histone methylase (MLL3), histone acetylases, CBP/P300, bind to the HOXB9 promoter EREs in the presence of BPA, modify chromatin (histone methylation and acetylation) and lead to gene activation. In summary, our results demonstrate that BPA exposure, like estradiol, increases HOXB9 expression in breast cells both in vitro and in vivo through a mechanism that involves increased recruitment of transcription and chromatin modification factors.

Ali A, Ielciu I, Alkreathy HM, Khan AA
KLF17 attenuates estrogen receptor α-mediated signaling by impeding ERα function on chromatin and determines response to endocrine therapy.
Biochim Biophys Acta. 2016; 1859(7):883-95 [PubMed] Related Publications
Luminal-like breast cancer expressing estrogen receptor α (ERα) is among the aggressive breast tumor subtypes and shows poor prognosis. KLF17 plays a key role in breast cancer inhibition. However, the underlying mechanisms by which KLF17 control breast cancer progression remains unknown. Here, we show that KLF17 antagonizes ERα-dependent signaling to suppress breast cancer progression. KLF17 alters ERα-binding pattern throughout the genome and co-localizes with ERα on chromatin. Mechanistically, KLF17 forms a complex with ERα that interferes with ERα binding on chromatin and thereby attenuates ERα-dependent pathway. KLF17 increases the methylation status of ERE target promoters by recruiting transcriptional corepressor N-CoR/HDAC1 complex and prevents RNA polymerase II binding to suppress ERα-dependent transcriptional activation. Importantly, KLF17 preoccupies a subset of ERE target gene promoters and inhibits interaction of ERα with chromatin. Conversely, estrogen signaling suppresses KLF17 transcription via ERα/HDAC1-dependent mechanism. KLF17 expression negatively correlates with ERα target genes in multiple breast cancer samples. Enhanced KLF17 expression sensitizes ERα-positive breast cancer cells to endocrine therapy. KLF17 expression is downregulated in luminal breast cancer subtypes and is associated with poor survival rates in breast cancer patients. Taken together, these results indicate that KLF17-ERα interaction plays a potential role in inhibition of ERα-dependent breast cancer progression and suggests an improved strategy for treatment of ERα-positive breast cancer patients.

Mognol GP, Carneiro FR, Robbs BK, et al.
Cell cycle and apoptosis regulation by NFAT transcription factors: new roles for an old player.
Cell Death Dis. 2016; 7:e2199 [PubMed] Article available free on PMC after 30/09/2017 Related Publications
The NFAT (nuclear factor of activated T cells) family of transcription factors consists of four Ca(2+)-regulated members (NFAT1-NFAT4), which were first described in T lymphocytes. In addition to their well-documented role in T lymphocytes, where they control gene expression during cell activation and differentiation, NFAT proteins are also expressed in a wide range of cells and tissue types and regulate genes involved in cell cycle, apoptosis, angiogenesis and metastasis. The NFAT proteins share a highly conserved DNA-binding domain (DBD), which allows all NFAT members to bind to the same DNA sequence in enhancers or promoter regions. The same DNA-binding specificity suggests redundant roles for the NFAT proteins, which is true during the regulation of some genes such as IL-2 and p21. However, it has become increasingly clear that different NFAT proteins and even isoforms can have unique functions. In this review, we address the possible reasons for these distinct roles, particularly regarding N- and C-terminal transactivation regions (TADs) and the partner proteins that interact with these TADs. We also discuss the genes regulated by NFAT during cell cycle regulation and apoptosis and the role of NFAT during tumorigenesis.

Bararia D, Kwok HS, Welner RS, et al.
Acetylation of C/EBPα inhibits its granulopoietic function.
Nat Commun. 2016; 7:10968 [PubMed] Article available free on PMC after 30/09/2017 Related Publications
CCAAT/enhancer-binding protein alpha (C/EBPα) is an essential transcription factor for myeloid lineage commitment. Here we demonstrate that acetylation of C/EBPα at lysine residues K298 and K302, mediated at least in part by general control non-derepressible 5 (GCN5), impairs C/EBPα DNA-binding ability and modulates C/EBPα transcriptional activity. Acetylated C/EBPα is enriched in human myeloid leukaemia cell lines and acute myeloid leukaemia (AML) samples, and downregulated upon granulocyte-colony stimulating factor (G-CSF)- mediated granulocytic differentiation of 32Dcl3 cells. C/EBPα mutants that mimic acetylation failed to induce granulocytic differentiation in C/EBPα-dependent assays, in both cell lines and in primary hematopoietic cells. Our data uncover GCN5 as a negative regulator of C/EBPα and demonstrate the importance of C/EBPα acetylation in myeloid differentiation.

Kitange GJ, Mladek AC, Schroeder MA, et al.
Retinoblastoma Binding Protein 4 Modulates Temozolomide Sensitivity in Glioblastoma by Regulating DNA Repair Proteins.
Cell Rep. 2016; 14(11):2587-98 [PubMed] Article available free on PMC after 30/09/2017 Related Publications
Here we provide evidence that RBBP4 modulates temozolomide (TMZ) sensitivity through coordinate regulation of two key DNA repair genes critical for recovery from TMZ-induced DNA damage: methylguanine-DNA-methyltransferase (MGMT) and RAD51. Disruption of RBBP4 enhanced TMZ sensitivity, induced synthetic lethality to PARP inhibition, and increased DNA damage signaling in response to TMZ. Moreover, RBBP4 silencing enhanced TMZ-induced H2AX phosphorylation and apoptosis in GBM cells. Intriguingly, RBBP4 knockdown suppressed the expression of MGMT, RAD51, and other genes in association with decreased promoter H3K9 acetylation (H3K9Ac) and increased H3K9 tri-methylation (H3K9me3). Consistent with these data, RBBP4 interacts with CBP/p300 to form a chromatin-modifying complex that binds within the promoter of MGMT, RAD51, and perhaps other genes. Globally, RBBP4 positively and negatively regulates genes involved in critical cellular functions including tumorigenesis. The RBBP4/CBP/p300 complex may provide an interesting target for developing therapy-sensitizing strategies for GBM and other tumors.

Duren RP, Boudreaux SP, Conneely OM
Genome Wide Mapping of NR4A Binding Reveals Cooperativity with ETS Factors to Promote Epigenetic Activation of Distal Enhancers in Acute Myeloid Leukemia Cells.
PLoS One. 2016; 11(3):e0150450 [PubMed] Article available free on PMC after 30/09/2017 Related Publications
Members of the NR4A subfamily of orphan nuclear receptors regulate cell fate decisions via both genomic and non-genomic mechanisms in a cell and tissue selective manner. NR4As play a key role in maintenance of hematopoietic stem cell homeostasis and are critical tumor suppressors of acute myeloid leukemia (AML). Expression of NR4As is broadly silenced in leukemia initiating cell enriched populations from human patients relative to normal hematopoietic stem/progenitor cells. Rescue of NR4A expression in human AML cells inhibits proliferation and reprograms AML gene signatures via transcriptional mechanisms that remain to be elucidated. By intersecting an acutely regulated NR4A1 dependent transcriptional profile with genome wide NR4A binding distribution, we now identify an NR4A targetome of 685 genes that are directly regulated by NR4A1. We show that NR4As regulate gene transcription primarily through interaction with distal enhancers that are co-enriched for NR4A1 and ETS transcription factor motifs. Using a subset of NR4A activated genes, we demonstrate that the ETS factors ERG and FLI-1 are required for activation of NR4A bound enhancers and NR4A target gene induction. NR4A1 dependent recruitment of ERG and FLI-1 promotes binding of p300 histone acetyltransferase to epigenetically activate NR4A bound enhancers via acetylation at histone H3K27. These findings disclose novel epigenetic mechanisms by which NR4As and ETS factors cooperate to drive NR4A dependent gene transcription in human AML cells.

Gu Y, Xiao L, Ming Y, et al.
Corilagin suppresses cholangiocarcinoma progression through Notch signaling pathway in vitro and in vivo.
Int J Oncol. 2016; 48(5):1868-76 [PubMed] Article available free on PMC after 30/09/2017 Related Publications
Corilagin is a natural plant polyphenol tannic acid with antitumor, anti-inflammatory, and anti-oxidative properties. However, the mechanisms of its actions are largely unknown. Our group reported that corilagin could induce cell inhibition in human breast cancer cell line MCF-7 and human liver hepatocellular carcinoma cell lines HepG2. We report here that corilagin inhibits cholangiocarcinoma (CCA) development through regulating Notch signaling pathway. We found that, in vitro, corilagin inhibited CCA cell proliferation, migration and invasion, promoted CCA cell apoptosis, and inhibited Notch1 and Notch signaling pathway protein expression. Co-immunoprecipitation was used to establish Notch intracellular domain (NICD) interaction with MAML1 and P300 in CCA. Importantly, corilagin reduced Hes1 mRNA level through inhibiting Hes1 promoter activity. In nude mice, corilagin inhibited CCA growth and repressed the expression of Notch1 and mTOR. These results indicate that corilagin may control CCA cell growth by downregulating the expression of Notch1. Therefore, our findings suggest that corilagin may have the potential to become a new therapeutic drug for human CCA.

Cianfrocca R, Tocci P, Rosanò L, et al.
Nuclear β-arrestin1 is a critical cofactor of hypoxia-inducible factor-1α signaling in endothelin-1-induced ovarian tumor progression.
Oncotarget. 2016; 7(14):17790-804 [PubMed] Article available free on PMC after 30/09/2017 Related Publications
Hypoxia-inducible factor-1α (HIF-1α) mediates the response to hypoxia or other stimuli, such as growth factors, including endothelin-1 (ET-1), to promote malignant progression in numerous tumors. The importance of cofactors that regulate HIF-1α signalling within tumor is not well understood. Here we elucidate that ET-1/ET(A) receptor (ET(A)R)-induced pathway physically and functionally couples the scaffold protein β-arrestin1 (β-arr1) to HIF-1α signalling. In epithelial ovarian cancer (EOC) cells, ET-1/ET(A)R axis induced vascular-endothelial growth factor (VEGF) expression through HIF-1α nuclear accumulation. In these cells, activation of ET(A)R by ET-1, by mimicking hypoxia, promoted the nuclear interaction between β-arr1 and HIF-1α and the recruitment of p300 acetyltransferase to hypoxia response elements on the target gene promoters, resulting in enhanced histone acetylation, and HIF-1α target gene transcription. Indeed, β-arr1-HIF-1α interaction regulated the enhanced expression and release of downstream targets, such as ET-1 and VEGF, required for tumor cell invasion and pro-angiogenic effects in endothelial cells. These effects were abrogated by β-arr1 or HIF-1α silencing or by pharmacological treatment with the dual ET-1 receptor antagonist macitentan. Interestingly, ET(A)R/β-arr1 promoted the self-amplifying HIF-1α-mediated transcription of ET-1 that sustained a regulatory circuit involved in invasive and angiogenic behaviors. In a murine orthotopic model of metastatic human EOC, treatment with macitentan, or silencing of β-arr1, inhibits intravasation and metastasis formation. Collectively, these findings reveal the interplay of β-arr1 with HIF-1α in the complexity of ET-1/ET(A)R signalling, mediating epigenetic modifications directly involved in the metastatic process, and suggest that targeting ET-1-dependent β-arr1/HIF-1α pathway by using macitentan may impair EOC progression.

Viziteu E, Grandmougin C, Goldschmidt H, et al.
Chetomin, targeting HIF-1α/p300 complex, exhibits antitumour activity in multiple myeloma.
Br J Cancer. 2016; 114(5):519-23 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Multiple myeloma (MM) is an incurable clonal plasma cell malignancy. The constitutive expression of HIF-1α in MM suggests that inhibition of HIF-1α-mediated transcription represents an interesting target in MM.
METHODS: As p300 is a crucial co-activator of hypoxia-inducible transcription, disrupting the complex HIF-1α/p300 to target HIF activity appears to be an attractive strategy.
RESULTS: We reported that chetomin, an inhibitor of HIF-1α/p300 interaction, exhibits antitumour activity in human myeloma cell lines and primary MM cells from patients.
CONCLUSIONS: Our data suggest that chetomin may be of clinical value in MM and especially for patients characterised by a high EP300/HIF-1α expression and a poor prognosis.

Boulding T, Wu F, McCuaig R, et al.
Differential Roles for DUSP Family Members in Epithelial-to-Mesenchymal Transition and Cancer Stem Cell Regulation in Breast Cancer.
PLoS One. 2016; 11(2):e0148065 [PubMed] Free Access to Full Article Related Publications
Dual-specificity phosphatases (DUSPs) dephosphorylate threonine/serine and tyrosine residues on their substrates. Here we show that DUSP1, DUSP4, and DUSP6 are involved in epithelial-to-mesenchymal transition (EMT) and breast cancer stem cell (CSC) regulation. DUSP1, DUSP4, and DUSP6 are induced during EMT in a PKC pathway signal-mediated EMT model. We show for the first time that the key chromatin-associated kinase PKC-θ directly regulates a subset of DUSP family members. DUSP1, DUSP4, and DUSP6 globally but differentially co-exist with enhancer and permissive active histone post-translational modifications, suggesting that they play distinct roles in gene regulation in EMT/CSCs. We show that nuclear DUSP4 associates with the key acetyltransferase p300 in the context of the chromatin template and dynamically regulates the interplay between two key phosphorylation marks: the 1834 (active) and 89 (inhibitory) residues central to p300's acetyltransferase activity. Furthermore, knockdown with small-interfering RNAs (siRNAs) shows that DUSP4 is required for maintaining H3K27ac, a mark mediated by p300. DUSP1, DUSP4, and DUSP6 knockdown with siRNAs shows that they participate in the formation of CD44hi/CD24lo/EpCAM+ breast CSCs: DUSP1 knockdown reduces CSC formation, while DUSP4 and DUSP6 knockdown enhance CSC formation. Moreover, DUSP6 is overexpressed in patient-derived HER2+ breast carcinomas compared to benign mammary tissue. Taken together, these findings illustrate novel pleiotropic roles for DUSP family members in EMT and CSC regulation in breast cancer.

Inoue H, Takahashi H, Hashimura M, et al.
Cooperation of Sox4 with β-catenin/p300 complex in transcriptional regulation of the Slug gene during divergent sarcomatous differentiation in uterine carcinosarcoma.
BMC Cancer. 2016; 16:53 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Uterine carcinosarcoma (UCS) represents a true example of cancer associated with epithelial-mesenchymal transition (EMT), which exhibits cancer stem cell (CSC)-like traits. Both Sox and β-catenin signal transductions play key roles in the regulation of EMT/CSC properties, but little is known about their involvement in UCS tumorigenesis. Herein, we focused on the functional roles of the Sox/β-catenin pathway in UCSs.
METHODS: EMT/CSC tests and transfection experiments were carried out using three endometrial carcinoma (Em Ca) cell lines. Immunohistochemical investigation was also applied for a total of 32 UCSs.
RESULTS: Em Ca cells cultured in STK2, a serum-free medium for mesenchymal stem cells, underwent changes in morphology toward an EMT appearance through downregulation of E-cadherin, along with upregulation of Slug, known as a target gene of β-catenin. The cells also showed CSC properties with an increase in the aldehyde dehydrogenase (ALDH) 1(high) activity population and spheroid formation, as well as upregulation of Sox4, Sox7, and Sox9. Of these Sox factors, overexpression of Sox4 dramatically led to transactivation of the Slug promoter, and the effects were further enhanced by cotransfection of Sox7 or Sox9. Sox4 was also able to promote β-catenin-mediated transcription of the Slug gene through formation of transcriptional complexes with β-catenin and p300, independent of TCF4 status. In clinical samples, both nuclear β-catenin and Slug scores were significantly higher in the sarcomatous elements as compared to carcinomatous components in UCSs, and were positively correlated with Sox4, Sox7, and Sox9 scores.
CONCLUSIONS: These findings suggested that Sox4, as well as Sox7 and Sox9, may contribute to regulation of EMT/CSC properties to promote development of sarcomatous components in UCSs through transcriptional regulation of the Slug gene by cooperating with the β-catenin/p300 signal pathway.

Ghaleb AM, Elkarim EA, Bialkowska AB, Yang VW
KLF4 Suppresses Tumor Formation in Genetic and Pharmacological Mouse Models of Colonic Tumorigenesis.
Mol Cancer Res. 2016; 14(4):385-96 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
UNLABELLED: The zinc finger transcription factor Krüppel-like factor 4 (KLF4) is frequently downregulated in colorectal cancer. Previous studies showed that KLF4 is a tumor suppressor in the intestinal tract and plays an important role in DNA damage-repair mechanisms. Here, the in vivo effects of Klf4 deletion were examined from the mouse intestinal epithelium (Klf4(ΔIS)) in a genetic or pharmacological setting of colonic tumorigenesis:Apc(Min/⁺) mutation or carcinogen treatment with azoxymethane (AOM), respectively.Klf4 (ΔIS)/Apc (Min/⁺) mice developed significantly more colonic adenomas with 100% penetrance as compared with Apc(Min/⁺) mice with intact Klf4 (Klf4(fl/fl)/Apc (Min/⁺)). The colonic epithelium of Klf4 (ΔIS)/Apc (Min/⁺)mice showed increased mTOR pathway activity, together with dysregulated epigenetic mechanism as indicated by altered expression of HDAC1 and p300. Colonic adenomas from both genotypes stained positive for γH2AX, indicating DNA double-strand breaks. InKlf4 (ΔIS)/Apc (Min/+) mice, this was associated with reduced nonhomologous end joining (NHEJ) repair and homologous recombination repair (HRR) mechanisms as indicated by reduced Ku70 and Rad51 staining, respectively. In a separate model, following treatment with AOM, Klf4 (ΔIS) mice developed significantly more colonic tumors than Klf4 (fl/fl) mice, with more Klf4 (ΔIS) mice harboring K-Rasmutations than Klf4 (fl/fl)mice. Compared with AOM-treated Klf4 (fl/fl)mice, adenomas of treated Klf4 (ΔIS) mice had suppressed NHEJ and HRR mechanisms, as indicated by reduced Ku70 and Rad51 staining. This study highlights the important role of KLF4 in suppressing the development of colonic neoplasia under different tumor-promoting conditions.
IMPLICATIONS: The study demonstrates that KLF4 plays a significant role in the pathogenesis of colorectal neoplasia.

Bouillez A, Rajabi H, Pitroda S, et al.
Inhibition of MUC1-C Suppresses MYC Expression and Attenuates Malignant Growth in KRAS Mutant Lung Adenocarcinomas.
Cancer Res. 2016; 76(6):1538-48 [PubMed] Article available free on PMC after 15/03/2017 Related Publications
Dysregulation of MYC expression is a hallmark of cancer, but the development of agents that target MYC has remained challenging. The oncogenic MUC1-C transmembrane protein is, like MYC, aberrantly expressed in diverse human cancers. The present studies demonstrate that MUC1-C induces MYC expression in KRAS mutant non-small cell lung cancer (NSCLC) cells, an effect that can be suppressed by targeting MUC1-C via shRNA silencing, CRISPR editing, or pharmacologic inhibition with GO-203. MUC1-C activated the WNT/β-catenin (CTNNB1) pathway and promoted occupancy of MUC1-C/β-catenin/TCF4 complexes on the MYC promoter. MUC1-C also promoted the recruitment of the p300 histone acetylase (EP300) and, in turn, induced histone H3 acetylation and activation of MYC gene transcription. We also show that targeting MUC1-C decreased the expression of key MYC target genes essential for the growth and survival of NSCLC cells, such as TERT and CDK4. Based on these results, we found that the combination of GO-203 and the BET bromodomain inhibitor JQ1, which targets MYC transcription, synergistically suppressed MYC expression and cell survival in vitro as well as tumor xenograft growth. Furthermore, MUC1 expression significantly correlated with that of MYC and its target genes in human KRAS mutant NSCLC tumors. Taken together, these findings suggest a therapeutic approach for targeting MYC-dependent cancers and provide the framework for the ongoing clinical studies addressing the efficacy of MUC1-C inhibition in solid tumors.

Khan P, Manna A, Saha S, et al.
Aspirin inhibits epithelial-to-mesenchymal transition and migration of oncogenic K-ras-expressing non-small cell lung carcinoma cells by down-regulating E-cadherin repressor Slug.
BMC Cancer. 2016; 16:39 [PubMed] Article available free on PMC after 15/03/2017 Related Publications
BACKGROUND: Cancer metastasis is one of the most common causes of treatment failure and death in cancer patients. It has been acknowledged that aberrant activation of epithelial-to-mesenchymal transition (EMT) program, endows cancer cells with metastatic competence for which E-cadherin switch is a well-established hallmark. Suppression of E-cadherin by its transcriptional repressor Slug is thus a determining factor for EMT. Here, we aimed at discerning (i) the molecular mechanisms that regulate Slug/E-cadherin axis in oncogenic K-ras-expressing non-small cell lung carcinoma (NSCLC) cells, and (ii) the effect of aspirin in modulating the same.
METHODS: The migratory behaviour of NSCLC cell line A549 were deciphered by wound healing assay. Further assessment of the molecular mechanisms was done by western blotting, RT-PCR, confocal microscopy, chromatin immunoprecipitation and small interfering RNA (siRNA)-mediated gene silencing.
RESULTS: Here we report that in oncogenic K-ras-expressing A549 cells, Ras/ERK downstream Elk-1 forms p-Elk-1-p300 complex that being directly recruited to SLUG promoter acetylates the same to ensure p65NFκB binding for transcriptional up-regulation of Slug, a transcriptional repressor of E-cadherin. Aspirin inhibits EMT and decelerates the migratory potential of A549 cells by down-regulating Slug and thereby up-regulating E-cadherin. Aspirin impedes activation and nuclear translocation of p65NFκB, essential for this transcription factor being available for SLUG promoter binding. As a consequence, Slug transcription is down-regulated relieving A549 cells from Slug-mediated repression of E-cadherin transcription, thereby diminishing the metastatic potential of these oncogenic Ras-expressing NSCLC cells.
CONCLUSIONS: Cumulatively, these results signify a crucial role of the anti-inflammatory agent aspirin as a novel negative regulator of epithelial-to-mesenchymal transition thereby suggesting its candidature as a promising tool for deterring metastasis of highly invasive K-ras-expressing NSCLC cells.

Tang R, Xu X, Yang W, et al.
MED27 promotes melanoma growth by targeting AKT/MAPK and NF-κB/iNOS signaling pathways.
Cancer Lett. 2016; 373(1):77-87 [PubMed] Related Publications
The inhibitors of BRAF and MEK targeting MAPK signaling pathway provide a comparatively effective therapeutic strategy for melanoma caused by BRAF mutation. However, melanoma, especially metastatic melanoma, has become one of the most threatening malignancies. Thus, the identification of exact molecular mechanisms and the key components involved in such mechanisms is urgently needed in order to provide new therapeutic options for patients with melanoma. Here, we identified MED27 as a potential melanoma target and explored its role and the associated molecular mechanism involved in melanoma progression. MED27 was found to be highly expressed in melanoma cells and tumor tissues. Its silencing led to melanoma cell proliferation inhibition, cell cycle arrest and apoptosis induction accompanied by the inactivation of PI3K/AKT and MAPK/ERK signaling and the activation of Bax/Cyto-C/Caspase-dependent apoptotic pathway. In addition, silencing of MED27 led to the decrease of iNOS expression through inhibiting the activation of a serial of upstream key proteins of NF-κB signaling pathway and the translocation of p50/p65 from cytoplasm to nucleus. MED27 was also found to be able to interact with NF-κB and p300 and to be acetylated by p300. Furthermore, the results in a xenograft tumor model indicated that melanoma progression was effectively suppressed by MED27 knockdown accompanied by the down-regulation of p-AKT, p-ERK, p-MEK1/2, MMP-9, Bcl-2 and iNOS expressions in the tumor tissues. Taken together, our study not only demonstrated the new function of MED27 as an oncogenic protein and the associated molecular mechanisms involved in melanoma progression, but also provided a possibility for the development of MED27 as a new anticancer target in melanoma therapy.

Xuan Y, Wang J, Ban L, et al.
hnRNPA2/B1 activates cyclooxygenase-2 and promotes tumor growth in human lung cancers.
Mol Oncol. 2016; 10(4):610-24 [PubMed] Related Publications
Cyclooxygenase-2 (COX-2) is highly expressed in tumor cells and has been regarded as a hallmarker for cancers, but the excise regulatory mechanism of COX-2 in tumorigenesis remains largely unknown. Here, we pulled down and identified a novel COX-2 regulator, heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1), which could specifically bind to COX-2 core promoter and regulate tumor growth in non-small-cell lung cancers (NSCLCs). Knockdown of hnRNPA2/B1 by shRNA or siRNA downregulated COX-2 expression and prostaglandin E2 (PGE2) production, and suppressed tumor cell growth in NSCLC cells in vitro and in vivo. Conversely, overexpression of hnRNPA2/B1 up-regulated the levels of COX-2 and PGE2 and promoted tumor cell growth. We also showed that hnRNPA2/B1 expression was positively correlated with COX-2 expression in NSCLC cell lines and tumor tissues, and the up-regulated expression of hnRNPA2/B1 and COX-2 predicted worse prognosis in NSCLC patients. Furthermore, we demonstrated that the activation of COX-2 expression by hnRNPA2/B1 was mediated through the cooperation with p300, a transcriptional co-activator, in NSCLC cells. The hnRNPA2/B1 could interact with p300 directly and be acetylated by p300. Exogenous overexpression of p300, but not its histone acetyltransferase (HAT) domain deletion mutation, augmented the acetylation of hnRNPA2/B1 and enhanced its binding on COX-2 promoter, thereby promoted COX-2 expression and lung cancer cell growth. Collectively, our results demonstrate that hnRNPA2/B1 promotes tumor cell growth by activating COX-2 signaling in NSCLC cells and imply that the hnRNPA2/B1/COX-2 pathway may be a potential therapeutic target for human lung cancers.

Wu TC, Lin YC, Chen HL, et al.
The enhancing effect of genistein on apoptosis induced by trichostatin A in lung cancer cells with wild type p53 genes is associated with upregulation of histone acetyltransferase.
Toxicol Appl Pharmacol. 2016; 292:94-102 [PubMed] Related Publications
Genistein has been shown to enhance the antitumor activity of trichostatin A (TSA) in human lung carcinoma A549 cells. However, whether the combined treatment exerts the same effect in other lung cancer cells is unclear. In the present study we first compared the enhancing effect of genistein on the antitumor effect of TSA in ABC-1, NCI-H460 (H460) and A549 cells. Second, we investigated whether the effects of genistein are associated with increased histone/non-histone protein acetylation. We found that the enhancing effect of genistein on cell-growth-arrest in ABC-1 cells (p53 mutant) was less than in A549 and H460 cells. Genistein enhanced TSA induced apoptosis in A549 and H460 cells rather than in ABC-1 cells. After silencing p53 expression in A549 and H460 cells, the enhancing effect of genistein was diminished. In addition, genistein increased TSA-induced histone H3/H4 acetylation in A549 and H460 cells. Genistein also increased p53 acetylation in H460 cells. The inhibitor of acetyltransferase, anacardic acid, diminished the enhancing effect of genistein on all TSA-induced histone/p53 acetylation and apoptosis. Genistein in combination with TSA increased the expression of p300 protein, an acetyltransferase, in A549 and NCI-H460 cells. Furthermore, we demonstrated that genistein also enhanced the antitumor effect of genistein in A549-tumor-bearing mice. Taken together, these results suggest that the enhancing effects of genistein on TSA-induced apoptosis in lung cancer cells were p53-dependent and were associated with histone/non-histone protein acetylation.

Robles AI, Traverso G, Zhang M, et al.
Whole-Exome Sequencing Analyses of Inflammatory Bowel Disease-Associated Colorectal Cancers.
Gastroenterology. 2016; 150(4):931-43 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
BACKGROUND & AIMS: A long duration of inflammatory bowel disease (IBD) increases the risk for colorectal cancer. Mutation analysis of limited numbers of genes has indicated that colorectal tumors that develop in patients with IBD differ from those of patients without IBD. We performed whole-exome sequencing analyses to characterize the genetic landscape of these tumors.
METHODS: We collected colorectal tumor and non-neoplastic tissues from 31 patients with IBD and colorectal cancer (15 with ulcerative colitis, 14 with Crohn's disease, and 2 with indeterminate colitis) and performed whole-exome sequencing analyses of the microdissected tumor and matched nontumor tissues. We identified somatic alterations by comparing matched specimens. The prevalence of mutations in sporadic colorectal tumors was obtained from previously published exome-sequencing studies.
RESULTS: Two specimens had somatic mutations in the DNA proofreading or mismatch repair genes POLE, MLH1, and MSH6 and the tumor cells had a hypermutable phenotype. The remaining tumors had, on average, 71 alterations per sample. TP53 was the most commonly mutated gene, with prevalence similar to that of sporadic colorectal tumors (63% of cases). However, tumors from the patients with IBD had a different mutation spectrum. APC and KRAS were mutated at significantly lower rates in tumors from patients with IBD than in sporadic colorectal tumors (13% and 20% of cases, respectively). Several genes were mutated more frequently or uniquely in tumors from patients with IBD, including SOX9 and EP300 (which encode proteins in the WNT pathway), NRG1 (which encodes an ERBB ligand), and IL16 (which encodes a cytokine). Our study also revealed recurrent mutations in components of the Rho and Rac GTPase network, indicating a role for noncanonical WNT signaling in development of colorectal tumors in patients with IBD.
CONCLUSIONS: Colorectal tumors that develop in patients with IBD have distinct genetic features from sporadic colorectal tumors. These findings could be used to develop disease-specific markers for diagnosis and treatment of patients with IBD and colorectal cancer.

Lin A, Li C, Xing Z, et al.
The LINK-A lncRNA activates normoxic HIF1α signalling in triple-negative breast cancer.
Nat Cell Biol. 2016; 18(2):213-24 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Although long non-coding RNAs (lncRNAs) predominately reside in the nucleus and exert their functions in many biological processes, their potential involvement in cytoplasmic signal transduction remains unexplored. Here, we identify a cytoplasmic lncRNA, LINK-A (long intergenic non-coding RNA for kinase activation), which mediates HB-EGF-triggered, EGFR:GPNMB heterodimer-dependent HIF1α phosphorylation at Tyr 565 and Ser 797 by BRK and LRRK2, respectively. These events cause HIF1α stabilization, HIF1α-p300 interaction, and activation of HIF1α transcriptional programs under normoxic conditions. Mechanistically, LINK-A facilitates the recruitment of BRK to the EGFR:GPNMB complex and BRK kinase activation. The BRK-dependent HIF1α Tyr 565 phosphorylation interferes with Pro 564 hydroxylation, leading to normoxic HIF1α stabilization. Both LINK-A expression and LINK-A-dependent signalling pathway activation correlate with triple-negative breast cancer (TNBC), promoting breast cancer glycolysis reprogramming and tumorigenesis. Our findings illustrate the magnitude and diversity of cytoplasmic lncRNAs in signal transduction and highlight the important roles of lncRNAs in cancer.

Conery AR, Centore RC, Neiss A, et al.
Bromodomain inhibition of the transcriptional coactivators CBP/EP300 as a therapeutic strategy to target the IRF4 network in multiple myeloma.
Elife. 2016; 5 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Pharmacological inhibition of chromatin co-regulatory factors represents a clinically validated strategy to modulate oncogenic signaling through selective attenuation of gene expression. Here, we demonstrate that CBP/EP300 bromodomain inhibition preferentially abrogates the viability of multiple myeloma cell lines. Selective targeting of multiple myeloma cell lines through CBP/EP300 bromodomain inhibition is the result of direct transcriptional suppression of the lymphocyte-specific transcription factor IRF4, which is essential for the viability of myeloma cells, and the concomitant repression of the IRF4 target gene c-MYC. Ectopic expression of either IRF4 or MYC antagonizes the phenotypic and transcriptional effects of CBP/EP300 bromodomain inhibition, highlighting the IRF4/MYC axis as a key component of its mechanism of action. These findings suggest that CBP/EP300 bromodomain inhibition represents a viable therapeutic strategy for targeting multiple myeloma and other lymphoid malignancies dependent on the IRF4 network.

Jia ZM, Ai X, Teng JF, et al.
p21 and CK2 interaction-mediated HDAC2 phosphorylation modulates KLF4 acetylation to regulate bladder cancer cell proliferation.
Tumour Biol. 2016; 37(6):8293-304 [PubMed] Related Publications
Krüppel-like factor 4 (KLF4) is a transcription factor involved in both tumor suppression and oncogenesis as a transcriptional activator or repressor in a context-dependent manner. KLF4 acts as a regulator of p53 depending on p21 status in breast cancer. However, the mechanisms underlying the distinct role of KLF4 remain poorly understood. Here, we revealed that p21 depletion converted KLF4 from a cell cycle inhibitor to a promoter of bladder cancer cell proliferation. Additionally, KLF4 was acetylated in a p21-dependent manner to inhibit bladder cancer cell growth as a tumor suppressor. However, deacetylated KLF4 functioned as an oncogene promoting bladder cancer cell proliferation. Mechanistically, p21 and CK2 interaction, but not CK2 alone, enhanced HDAC2 phosphorylation and restricted KLF4 deacetylation and subsequent tumor promotion. Furthermore, we observed that KLF4 was acetylated by CBP/p300 and that overexpression of CBP resulted in KLF4 acetylation and tumor suppression even in p21-depleted bladder cancer cells. Moreover, we discovered that Notch-1 knockdown-induced KLF4 is acetylated form of KLF4, which may mediate Notch-1 function in bladder cancer cell proliferation. Our data demonstrate that KLF4 acts as a tumor suppressor or oncogene to activate or repress target gene transcription depending on its acetylation status, which is regulated by p21 and CK2 interaction-mediated HDAC2 phosphorylation. Targeting KLF4 at the post-transcriptional levels may provide novel insight for bladder cancer therapy.

Ajiro M, Jia R, Yang Y, et al.
A genome landscape of SRSF3-regulated splicing events and gene expression in human osteosarcoma U2OS cells.
Nucleic Acids Res. 2016; 44(4):1854-70 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Alternative RNA splicing is an essential process to yield proteomic diversity in eukaryotic cells, and aberrant splicing is often associated with numerous human diseases and cancers. We recently described serine/arginine-rich splicing factor 3 (SRSF3 or SRp20) being a proto-oncogene. However, the SRSF3-regulated splicing events responsible for its oncogenic activities remain largely unknown. By global profiling of the SRSF3-regulated splicing events in human osteosarcoma U2OS cells, we found that SRSF3 regulates the expression of 60 genes including ERRFI1, ANXA1 and TGFB2, and 182 splicing events in 164 genes, including EP300, PUS3, CLINT1, PKP4, KIF23, CHK1, SMC2, CKLF, MAP4, MBNL1, MELK, DDX5, PABPC1, MAP4K4, Sp1 and SRSF1, which are primarily associated with cell proliferation or cell cycle. Two SRSF3-binding motifs, CCAGC(G)C and A(G)CAGCA, are enriched to the alternative exons. An SRSF3-binding site in the EP300 exon 14 is essential for exon 14 inclusion. We found that the expression of SRSF1 and SRSF3 are mutually dependent and coexpressed in normal and tumor tissues/cells. SRSF3 also significantly regulates the expression of at least 20 miRNAs, including a subset of oncogenic or tumor suppressive miRNAs. These data indicate that SRSF3 affects a global change of gene expression to maintain cell homeostasis.

Araf S, Okosun J, Koniali L, et al.
Epigenetic dysregulation in follicular lymphoma.
Epigenomics. 2016; 8(1):77-84 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
The adoption of next-generation sequencing technologies has led to a remarkable shift in our understanding of the genetic landscape of follicular lymphoma. While the disease has been synonymous with the t(14;18), the prevalence of alterations in genes that regulate the epigenome has been established as a pivotal hallmark of these lymphomas. Giant strides are being made in unraveling the biological consequences of these alterations in tumorigenesis opening up new opportunities for directed therapies.

Paladino D, Yue P, Furuya H, et al.
A novel nuclear Src and p300 signaling axis controls migratory and invasive behavior in pancreatic cancer.
Oncotarget. 2016; 7(6):7253-67 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
The presence of Src in the nuclear compartment has been previously reported, although its significance has remained largely unknown. We sought to delineate the functions of the nuclear pool of Src within the context of malignant progression. Active Src is localized within the nuclei of human pancreatic cancer cells and mouse fibroblasts over-expressing c-Src where it is associated with p300. Nuclear Src additionally promotes the tyrosine phosphorylation of p300 in pancreatic cancer Panc-1 cells. Src, together with p300, is associated with the high-mobility group AT-hook (HMGA)2 and SET and MYND domain-containing protein (SMYD)3 gene promoters and regulates their expression in a Src-dependent manner. These nuclear Src-dependent events correlate with anchorage-independent soft-agar growth and the migratory properties in both pancreatic Panc-1 cells and mouse fibroblasts over-expressing Src. Moreover, analyses of human pancreatic ductal adenocarcinoma (PDAC) tumor tissues detected the association of nuclear Src with the HMGA2 and SMYD3 gene promoters. Our findings for the first time show the critical importance of nuclear Src and p300 function in the migratory properties of pancreatic cancer cells. Further, data together identify a previously unknown role of nuclear Src in the regulation of gene expression in association with p300 within the context of cells harboring activated or over-expressing Src. This novel mechanism of nuclear Src-p300 axis in PDAC invasiveness and metastasis may provide an opportunity for developing more effective early clinical interventions for this lethal disease.Active Src is complexed with and phosphorylates p300 in the nucleus, and the complex is bound to HMGA2 and SMYD3 genes, thereby regulating their expression to promote pancreatic tumor cell migration and invasiveness.

van Galen P, Viny AD, Ram O, et al.
A Multiplexed System for Quantitative Comparisons of Chromatin Landscapes.
Mol Cell. 2016; 61(1):170-80 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Genome-wide profiling of histone modifications can provide systematic insight into the regulatory elements and programs engaged in a given cell type. However, conventional chromatin immunoprecipitation and sequencing (ChIP-seq) does not capture quantitative information on histone modification levels, requires large amounts of starting material, and involves tedious processing of each individual sample. Here, we address these limitations with a technology that leverages DNA barcoding to profile chromatin quantitatively and in multiplexed format. We concurrently map relative levels of multiple histone modifications across multiple samples, each comprising as few as a thousand cells. We demonstrate the technology by monitoring dynamic changes following inhibition of p300, EZH2, or KDM5, by linking altered epigenetic landscapes to chromatin regulator mutations, and by mapping active and repressive marks in purified human hematopoietic stem cells. Hence, this technology enables quantitative studies of chromatin state dynamics across rare cell types, genotypes, environmental conditions, and drug treatments.

Park C, Ha SY, Kim ST, et al.
Identification of the BRAF V600E mutation in gastroenteropancreatic neuroendocrine tumors.
Oncotarget. 2016; 7(4):4024-35 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Genomic profiles of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are still insufficiently understood, and the genetic alterations associated with drug responses have not been studied. Here, we performed whole exome sequencing of 12 GEP-NETs from patients enrolled in a nonrandomized, open-labeled, single-center phase II study for pazopanib, and integrated our results with previously published results on pancreas (n = 12) and small intestine NETs (n = 50). The mean numbers of somatic mutations in each case varied widely from 20 to 4682. Among 12 GEP-NETs, eight showed mutations of more than one cancer-related gene, including TP53, CNBD1, RB1, APC, BCOR, BRAF, CTNNB1, EGFR, EP300, ERBB3, KDM6A, KRAS, MGA, MLL3, PTEN, RASA1, SMARCB1, SPEN, TBC1D12, and VHL. TP53 was recurrently mutated in three cases, whereas CNBD1 and RB1 mutations were identified in two cases. Three GEP-NET patients with TP53 mutations demonstrated a durable response and one small intestinal grade (G) 1 NET patient with BRAF V600E mutation showed progression after pazopanib treatment. We found BRAF V600E (G1 NET from rectum and two G3 NETs from colon) and BRAF G593S (G2 NET from pancreas) missense mutations (9.1%) in an independent cohort of 44 GEP-NETs from the rectum (n = 26), colon (n = 7), pancreas (n = 4), small intestine (n = 3), stomach (n = 3) and appendix (n = 1) by Sanger sequencing. All tumor specimens were obtained before chemotherapy. In conclusion, BRAF V600E mutation is likely to result in resistance to pazopanib but may be a potentianally actionable mutation in metastatic GEP-NETs patients.

Kasaian K, Wiseman SM, Walker BA, et al.
The genomic and transcriptomic landscape of anaplastic thyroid cancer: implications for therapy.
BMC Cancer. 2015; 15:984 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
BACKGROUND: Anaplastic thyroid carcinoma is the most undifferentiated form of thyroid cancer and one of the deadliest of all adult solid malignancies. Here we report the first genomic and transcriptomic profile of anaplastic thyroid cancer including those of several unique cell lines and outline novel potential drivers of malignancy and targets of therapy.
METHODS: We describe whole genomic and transcriptomic profiles of 1 primary anaplastic thyroid tumor and 3 authenticated cell lines. Those profiles augmented by the transcriptomes of 4 additional and unique cell lines were compared to 58 pairs of papillary thyroid carcinoma and matched normal tissue transcriptomes from The Cancer Genome Atlas study.
RESULTS: The most prevalent mutations were those of TP53 and BRAF; repeated alterations of the epigenetic machinery such as frame-shift deletions of HDAC10 and EP300, loss of SMARCA2 and fusions of MECP2, BCL11A and SS18 were observed. Sequence data displayed aneuploidy and large regions of copy loss and gain in all genomes. Common regions of gain were however evident encompassing chromosomes 5p and 20q. We found novel anaplastic gene fusions including MKRN1-BRAF, FGFR2-OGDH and SS18-SLC5A11, all expressed in-frame fusions involving a known proto-oncogene. Comparison of the anaplastic thyroid cancer expression datasets with the papillary thyroid cancer and normal thyroid tissue transcriptomes suggested several known drug targets such as FGFRs, VEGFRs, KIT and RET to have lower expression levels in anaplastic specimens compared with both papillary thyroid cancers and normal tissues, confirming the observed lack of response to therapies targeting these pathways. Further integrative data analysis identified the mTOR signaling pathway as a potential therapeutic target in this disease.
CONCLUSIONS: Anaplastic thyroid carcinoma possessed heterogeneous and unique profiles revealing the significance of detailed molecular profiling of individual tumors and the treatment of each as a unique entity; the cell line sequence data promises to facilitate the more accurate and intentional drug screening studies for anaplastic thyroid cancer.

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