bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1378: The histone methyltransferase adaptor WDR5 is a novel cofactor in neuroblastoma
Authors: Sun Yuting , Liu Pei Yan , Carter Daniel , Sokolowski Nicolas , MacKenzie Karen L. , Marshall Glenn M. , Liu Tao
Published: May 2015

Introduction: Neuroblastoma is the most common extracranial solid malignancy in early childhood. WDR5 is an essential component of the MLL and SET1/COMPASS histone H3 lysine 4 (H3K4) methyltransferase complex and plays a key role in the trimethylation of H3K4. However, there is no previous study establishing the role of WDR5 in neuroblastoma.

Results: Affymetrix gene array studies showed that knocking-down WDR5 expression with siRNAs reduced the expression of the cell cycle genes cyclin E1. Consistently, RT-PCR and immunoblot confirmed that WDR5 siRNAs reduced cyclin E1 mRNA and protein expression, ChIP assays showed that WDR5 siRNAs reduced histone H3K4 tri-methylation at the cyclin E1 gene promoter, and Alamar blue assays demonstrated that WDR5 induced neuroblastoma cell proliferation. Additionally, high levels of WDR5 gene expression in human neuroblastoma tissues predict poor patient survival independent of patient age and disease stage.

Conclusions: Our data demonstrate WDR5 as a novel co-factor in neuroblastoma oncogenesis, and provide critical evidence to support the application of WDR5 inhibitors for the therapy of neuroblastoma patients.

Citation Format: Yuting Sun, Pei Yan Liu, Daniel Carter, Nicolas Sokolowski, Karen L. MacKenzie, Glenn M. Marshall, Tao Liu. The histone methyltransferase adaptor WDR5 is a novel cofactor in neuroblastoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1378. doi:10.1158/1538-7445.AM2014-1378
Abstract 1379: Identification of global DNA methylation signatures in glioblastoma-derived cancer stem cells
Authors: Lee Eun Joon , Rath Prakash , Liu Jimei , Ryu Dungsheng , Free Alan , Pei Lirong , Anthony Douglas C , Sharma Suash , Kirk Mark D , Laterra John J. , Ryu Duck Hwan , Choi Jeong-Hyeon , Shi Huidong , Miller Douglas C. , Litofsky N. Scott , Feng Qi
Published: May 2015

Glioblastoma (GBM) is the most common and most aggressive brain tumor in adults. Its frequent recurrence after resection and dismal prognosis are thought to be due to a small population of stem-like tumor cells that efficiently propagate tumors and resist cytotoxic therapy. In this study, we performed an in depth analysis of the DNA methylation landscape in GBM-derived cancer stem cells (GSCs). Parallel comparisons of primary GBM tumors and GSC lines derived from these tumors with normal controls (a neural stem cell (NSC) line and normal brain tissue) identified two groups hyper- and hypomethylated of genes that display a trend of either increasing or decreasing methylation levels in the order of controls, primary GBMs, and their counterpart GSC lines, respectively. Interestingly, concurrent promoter hypermethylation and gene body hypomethylation were observed in a subset of genes including MGMT, AJAP1 and PTPRN2. These unique DNA methylation signatures were also be found in primary GBM-derived xenograft tumors suggesting that they were not tissue culture-related epigenetic changes. Integration of GSC-specific epigenetic signatures with gene expression analysis further identified candidate tumor suppressor genes that are frequently down regulated in GBMs such as SPINT2, NEFM, and PENK. The comparison between the NSC line and the normal brain tissue sample leads to the identification of a group of NSC-specific differentially methylated regions (nsDMRs). Cluster analysis using nsDMRs revealed the presence of stem cell-specific DNA methylation signatures in both primary GBM and GSC lines. Higher expression of genes associated with stem cell-specific DNA methylation signatures such as DNMT3A, STAT5A, CSTB, PMEPA1 and G6PD in GBM patients was found to be associated with poor patient survival. The results from this study demonstrate the utility of using cancer stem cell models for advancing understanding of the pathobiology of gliomas.

Citation Format: Eun Joon Lee, Prakash Rath, Jimei Liu, Dungsheng Ryu, Alan Free, Lirong Pei, Douglas C Anthony, Suash Sharma, Mark D Kirk, John J. Laterra, Duck Hwan Ryu, Jeong-Hyeon Choi, Huidong Shi, Douglas C. Miller, N. Scott Litofsky, Qi Feng. Identification of global DNA methylation signatures in glioblastoma-derived cancer stem cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1379. doi:10.1158/1538-7445.AM2014-1379
Abstract 1382: Developmental exposure to BPA increases the prostate cancer susceptibility via reprogramming of androgen-responsive genes via increased H3K4me3 methylation
Authors: Wang Quan , Wong Rebecca Lee Yean , Kusewitt Donna F. , Bosland Maarten C. , Chen Jing , Medvedovic Mario , Prins Gail S. , Kannan Kurunthachalam , Ho Shuk-Mei , Walker Cheryl Lyn
Published: May 2015

Background:

Early life exposure to endocrine disrupting compounds (EDCs) during critical developmental periods increases susceptibility to cancer and other diseases in adulthood. Because EDC exposures cause life-long changes in gene expression of target tissues, identification of gene targets for developmental reprogramming holds promise for both understanding the etiology of environmental causes of cancer and development of biomarkers of EDC exposure.

Aim:

Our goal was to identify targets for developmental reprogramming in the prostate using a rat model for development of hormone-dependent early prostate (PIN) lesions induced by the EDC bisphenol A (BPA).

Methods:

Rats were exposed neonatally to vehicle or BPA and assessed at 12 months for development of hormone-dependent prostate lesions. Epigenetic status and gene expression were profiled in the at-risk (d70) adult prostate using CHIP- and RNA-seq, with qRT-PCR and ChIP used to confirm changes in gene expression and histone methylation (respectively).

Results:

As expected, BPA exposure significantly increased PIN lesions and the dysplasia score in 12 mo rats. CHIP-seq in adult rats (day 70) prior to lesion development showed a significant increase in histone H3, lysine 4 trimethylation (H3K4me3) levels in prostate cancer-associated KEGG pathway genes of rats exposed to BPA neonatally. Changes reflective of both increased basal, as well as hormone-induced, KEGG pathway gene expression were observed in BPA exposed animals at increased risk for development of PIN lesions.

Conclusion:

Neonatal BPA exposure reprograms the developing prostate to alter gene expression in adulthood and increase incidence and severity of prostatic dysplasia. Several KEGG-pathway prostate cancer pathway genes were identified as targets for epigenetic reprogramming, providing new tools for future studies to understand gene-environment interactions as determinants of prostate cancer risk.

Citation Format: Quan Wang, Rebecca Lee Yean Wong, Donna F. Kusewitt, Maarten C. Bosland, Jing Chen, Mario Medvedovic, Gail S. Prins, Kurunthachalam Kannan, Shuk-Mei Ho, Cheryl Lyn Walker. Developmental exposure to BPA increases the prostate cancer susceptibility via reprogramming of androgen-responsive genes via increased H3K4me3 methylation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1382. doi:10.1158/1538-7445.AM2014-1382
Abstract 1386: Enhanced expression of HMGA1 and THY1 in human hepatocellular carcinoma correlates with poor prognosis
Authors: Andreozzi Mariacarla , Quagliata Luca , Benz David , Trapani Francesca , Eppenberger-Castori Serenella , Ruiz Christian , Pallante Pierlorenzo , Heim Markus , Tornillo Luigi , Fusco Alfredo , Piscuoglio Salvatore , Terracciano Luigi Maria
Published: May 2015

Background and aim: Mounting evidence suggest that hepatocellular carcinoma (HCC) contains a subset of cells possessing some functional properties similar to normal tissue stem cells, usually referred as cancer stem cells (CSCs). THY1 (aka CD90) is involved in tumor-genesis and is commonly acknowledged as a maker of CSC in HCC. HMGA1, an HMG (high mobility group) chromatin-remodelling protein, has been recently highlighted as a key player in stem cell biology. HMGA1 overexpression induces malignant transformation in vitro and is deregulated in many cancer entities. This study aims to address the interrelated role of HMGA1 and THY1 in HCC.

Methods: Using a global transcriptomic profiling (Affymetrix), validated by RT-qPCR, we analysed HMGA1 and THY1 expression levels in a cohort of HCC needle biopsy matched with corresponding non-neoplastic liver (total n=118) and normal liver (n=5). Using tissue microarray (TMA) technology, we evaluated by immunohistochemical staining HMGA1 and THY1 protein levels in a large collective of liver specimens (n=434, of which n=216 were HCCs).

Results: We observed that both HMGA1 and THY1 expression is significantly up regulated in a subset of HCC specimens, correlating with metastatic disease and histological grading. Additionally, we demonstrate that high HMGA1 protein levels along with THY1 positivity in HCC samples results in unfavorable patients' outcome and disease progression.

Conclusion: With this work we provide new evidence for HMGA1 and THY1 involvement in HCC progression and disease outcome and set the basis for further studies aiming to address their role in CSC biology of HCC.

Citation Format: Mariacarla Andreozzi, Luca Quagliata, David Benz, Francesca Trapani, Serenella Eppenberger-Castori, Christian Ruiz, Pierlorenzo Pallante, Markus Heim, Luigi Tornillo, Alfredo Fusco, Salvatore Piscuoglio, Luigi Maria Terracciano. Enhanced expression of HMGA1 and THY1 in human hepatocellular carcinoma correlates with poor prognosis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1386. doi:10.1158/1538-7445.AM2014-1386
Abstract 1392: The Pursuit of p73 Regulation: interaction partners tell many different stories
Authors: Satija Yatendra K. , Das Sanjeev
Published: May 2015

p73 is a member of the p53 tumor suppressor family, which can trigger cell cycle arrest and apoptosis through its ability to bind p53 DNA target sites, thereby it acts as a negative regulator of tumorigenesis. Similar to p53, at normal state p73 is maintained at very low level but it rapidly gets induced upon genotoxic stress. Accumulating evidences demonstrated that p73 is mainly regulated at the protein level but its significance is still not clearly understood. It is believed that it is a consequence of post-translational modifications (PTMs) of p73 upon DNA damage. Emerging reports suggested that other than PTMs, various co-factors are responsible for regulating its level and activity. But all these reports remained inadequate to explain the molecular mechanisms behind regulation and activity of p73 under non-stressed and stressed conditions. The aim of our study is to find out novel interactors of p73 which distinctively affect its stability and activity in normal state and upon DNA damage.

We employed a proteomic approach to identify differential interactors of p73 under unstressed and genotoxic stress conditions. We prepared adenovirus system to ectopically overexpress dual-tagged p73 into cells. Our tandem affinity purification screening lead us to identification of many p73-associated proteins. Among the novel interactors, TRIM28, a RING-type E3 ligase, was of particular interest because it interacts with p73 under unstressed condition but no visible interaction was detected after DNA damage. We show here that TRIM28 ubiquitylates and targets p73 for proteasome-mediated degradation in unstressed conditions. Upon genotoxic stress, p73 gets phosphorylated at tyrosine 99 position in c-Abl-dependent manner leading to abrogation of its interaction with TRIM28 which subsequently leads to p73 stabilization. Another protein, MED15 was of particular interest because it interacts with p73 in phosphorylation-dependent manner and it serves as a coactivator of p73. Interestingly, we found that phosphorylation of p73 is a prerequisite for its interaction with MED15. Furthermore, loss of MED15 leads to decline in p73-mediated transactivation of its downstream target genes under DNA damaging conditions. Therefore, we propose a model in which DNA damage-induced phosphorylation of p73 affects its interaction with its negative regulator and leads to its preferential association with its coactivator.

Citation Format: Yatendra K. Satija, Sanjeev Das. The Pursuit of p73 Regulation: interaction partners tell many different stories. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1392. doi:10.1158/1538-7445.AM2014-1392
Abstract 1395: Identification of genes and pathways related to lymphovascular invasion in axillary-node negative breast cancer: A bioinformatic analysis of gene expression data
Authors: Blais Mathieu , Pinnaduwage Dushanthi , Bull Sheley , Andrulis Irene L.
Published: May 2015

Breast Cancer patients whose disease has not spread to the lymph nodes (axillary node-negative breast cancer, ANNBC) generally have a good prognosis; however, 20-30% will experience a recurrence. We previously reported that the presence of Lymphovascular invasion (LVI) is an independent predictor of recurrence in ANNBC. Given that breast cancers generally metastasize through LVI, identification of genes with altered expression when comparing LVI+ from LVI- tumors is relevant from both the fundamental and the clinical perspective. To discover genes and pathways involved in LVI and recurrence in ANNBC we performed differential gene expression microarray analysis of LVI+ (n = 37) and LVI- (n=68) ANNBC tumors and assessed pathway enrichment using Ingenuity IPA. We also analysed differences within the LVI+ group designed to compare genes for their association with early recurrence (n = 14; ≤ 4 years) versus free of recurrence for at least 10 years (n = 23). The biofunctions predicted to be activated that distinguish LVI+ from LVI- tumors are largely related to cell movement and invasion. Those enriched in the subset of patients with early recurrence were mostly related to cell fate. In addition, we observed that inflammation related pathways are enriched in the LVI+ subgroup that undergoes early recurrence. TGF-β1 was predicted to be an upstream regulator in the LVI+ vs LVI- dataset and also highly ranked in the early recurrence vs. late recurrence analysis. Our bioinformatics analyses are consistent with a migratory phenotype for cancer cells associated with LVI. The results suggest important pathways as well as upstream regulators associated with LVI and recurrence that are involved in invasion and cell fate biofunctions. The findings are currently being evaluated through validation and functional studies.

Note: This abstract was not presented at the meeting.

Citation Format: Mathieu Blais, Dushanthi Pinnaduwage, Sheley Bull, Irene L. Andrulis. Identification of genes and pathways related to lymphovascular invasion in axillary-node negative breast cancer: A bioinformatic analysis of gene expression data. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1395. doi:10.1158/1538-7445.AM2014-1395
Abstract 1396: Musashi 1 stabilizes TAC1 transcript in breast cancer cells to increase the production of onco-substance P
Authors: Nahas George R. , Murthy Raghav G. , Patel Shyam A. , Greco Steven J. , Rameshwar Pranela
Published: May 2015

Despite improved education and aggressive treatments, the mortality of breast cancer (BC) remains high. The TAC1 gene exerts oncogenic effects partly due to its major peptide, substance P, inducing the production of cytokines, which facilitate expression of the tumor-promoting truncated neurokinin-1 receptor. In turn, TAC1 facilitates metastasis to bone marrow and brain. TAC1 expression in BC cells (BCCs) occurs partly through increased translation of its mRNA. Cytosolic extracts from TAC1-expressing cells (BCCs and ectopic expression in non-tumorigenic breast cells) were analyzed for the candidate RNA-binding protein. In vitro translational, RNA stabilization, RNA shift and proteomic analyses identified a 40 kDa binding protein, which interacted with Exon 7 of the 3′ UTR of TAC1. Western blots and RNA supershift assay identified musashi 1 (Msi1) as the TAC1 mRNA binding protein. The data also indicated that TAC1 expression was sufficient for an increase in Msi1. A reporter gene system utilizing the TAC1 3′ UTR indicated that Msi1 competed with the endogenous translational suppressors, miR-130a and -206 for the same interacting site. Use of anti-miRs, Msi1 shRNA and the reporter gene system confirmed Msi1 as the stabilizer of TAC1 mRNA to increase the production of substance P. In vivo studies with nude mice showed reduced tumor growth with Msi1 knockdown BCCs compared to control. Msi1 knockdown retracted the tumor, indicating a role in tumor initiation. These findings correlated with a loss of two stem cell genes, REST and Oct4. In summary, this study identified Msi1 as a central RNA binding protein, which enhanced expression of the oncogenic TAC1 in BCCs. The data also suggested that Msi1, through TAC1 might be important in tumor initiation. These findings have clinical implications as a new drug target to reverse the oncogenic effects of TAC1. Furthermore, the feasibility of targeting TAC1 is evident since its receptor antagonist such as aprepitant are already approved by the FDA.

Citation Format: George R. Nahas, Raghav G. Murthy, Shyam A. Patel, Steven J. Greco, Pranela Rameshwar. Musashi 1 stabilizes TAC1 transcript in breast cancer cells to increase the production of onco-substance P. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1396. doi:10.1158/1538-7445.AM2014-1396
Abstract 1397: Simultaneous down-regulation of WWOX and DOK1 genes in non-small cell lung cancer (NSCLC) patients
Authors: Baykara Onur , Ekizoglu Seda , Tuna Esin , Demirkaya Ahmet , Kaynak Kamil , Kose Hikmet , Buyru Nur
Published: May 2015

Lung cancer is the main cause of cancer-related death worldwide and genetic, epigenetic and environmental factors affect the outcome of the disease. The WW domain-containing oxidoreductase (WWOX) gene is a putative tumor suppressor gene located on chromosome 16q23.3-24.1. It is composed of 9 exons and codes for a 414 amino acid protein. The WWOX gene has been previously reported to lose its tumor suppressor effect in several types of cancer including lung, ovarian, breast, stomach, uroepithelial and nasopharyngeal carcinomas. Docking Protein 1 (DOK1) is another putative tumor suppressor gene located on chromosome 2p13 and is known to be down-regulated and hypermethylated in various types of cancer including lung, breast or head and neck cancers and Burkitt lymphoma. WWOX activates MEK2 (MAP2K2-mitogen activated protein kinase kinase 2) which plays a crucial role in mitogen growth factor signal transduction. This activation increases ERK signaling in the MAPK/ERK pathway leading to transcription. The WWOX protein has two WW (tryptophan) domains which recognize the proline-rich region of other proteins. The DOK1 protein has a proline-rich region on its COOH terminal which may interact with the WWOX protein. DOK1 activates the RAS-GAP (GTPase activating proteins) signaling pathway leading to transcription when it is phosphorylated. Both WWOX and DOK1 also play important roles in the wnt/beta-catenin signaling pathway. The aim of this study was to investigate the relationship between WWOX and DOK genes by analyzing the expression levels of WWOX and DOK1 using RT-PCR in tumor tissue samples obtained from patients with non small cell lung cancer (NSCLC). When we analyzed expression levels by Spearman's Rank Correlation Coefficient Test, we observed down-regulation of the WWOX and DOK1 expression by 92.3% and 69.4% of the patients, respectively. Expression levels of WWOX and DOK both decreased simultaneously in 66.7% of the patients. We found a significant positive correlation between the expression levels of the WWOX and DOK1 genes when analyzed using the Wilcoxon Signed Ranks Test (p=0.033).

Citation Format: Onur Baykara, Seda Ekizoglu, Esin Tuna, Ahmet Demirkaya, Kamil Kaynak, Hikmet Kose, Nur Buyru. Simultaneous down-regulation of WWOX and DOK1 genes in non-small cell lung cancer (NSCLC) patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1397. doi:10.1158/1538-7445.AM2014-1397
Abstract 1398: Targeting novel co-activators of androgen receptor in castration resistant prostate cancer
Authors: Malik Rohit , Khan Amjad P. , Prensner John R. , Iyer Matthew K. , Borkin Dmitry , Wang Xiaoju , Jiang Xia , Subramaniam Shruthi , Shi Yang , Stender Rachell , Wu Yi-Mi , Cao Xuhong , Grembecka Jolanta , Cierpicki Tomasz , Chinnaiyan Arul
Published: May 2015

Resistance to androgen deprivation therapies and increased androgen receptor (AR) activity are major drivers of castrate resistant prostate cancer (CRPC), an advanced and frequently lethal form of this disease. Substantial prior work has focused on targeting AR directly; however, the identification and therapeutic targeting of co-activators of AR signaling remains an underexplored area of potential clinical significance. Here we demonstrate that the MLL complex acts as a co-activator of AR signaling. AR directly interacts with the sub-unit menin to recruit MLL and its complex to AR target genes. Inhibition of the menin-MLL interaction can block AR signaling and inhibit the formation of castration resistant tumors in vivo. Furthermore, we find that menin is up-regulated in localized and metastatic prostate cancer and high menin expression correlates with poor overall survival. Taken together our study identifies a novel co-activator complex of AR that can be targeted in CRPCs.

Citation Format: Rohit Malik, Amjad P. Khan, John R. Prensner, Matthew K. Iyer, Dmitry Borkin, Xiaoju Wang, Xia Jiang, Shruthi Subramaniam, Yang Shi, Rachell Stender, Yi-Mi Wu, Xuhong Cao, Jolanta Grembecka, Tomasz Cierpicki, Arul Chinnaiyan. Targeting novel co-activators of androgen receptor in castration resistant prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1398. doi:10.1158/1538-7445.AM2014-1398
Abstract 1399: NRF2 mutations are frequent in early rat preneoplastic hepatic lesions and in human hepatocellular carcinomas positive for the stem/progenitor cell marker KRT-19
Authors: Zavattari Patrizia , Perra Andrea , Kowalik Marta A. , Angioni Maddalena M. , Menegon Silvia , Petrelli Annalisa , Quagliata Luca , Ledda-Columbano Giovanna M. , Terraciano Luigi , Giordano Silvia , Columbano Amedeo
Published: May 2015

Hepatocellular carcinoma (HCC) is a multistage process but the nature of the molecular changes associated to the different steps, particularly the very early steps, is largely unknown. Recently, we have shown that activation of the Keap-1-NRF2 pathway is a very early event in the Resistant-Hepatocyte (R-H) rat model of hepatocarcinogenesis, suggesting that dysregulation of this pathway may have a causal role in HCC development.

The aim of the present study was to investigate by Sanger fluorescence-based sequence analysis whether and when NRF2 mutations could occur in this experimental model. The results showed that mutations of NRF2 are extremely frequent (17/19; 90%) in early preneoplastic lesions positive for the stem/progenitor cell marker KRT-19, which are considered to be the precursor cell population of HCC in this model. Notably, all the mutations were missense and involved the Keap1-NRF2 binding regions. Mutations of Keap-1 were more rare and were found only in preneoplastic lesions lacking NRF2 mutations (10%). KRT-19 positive HCCs arising 1 year later also showed a high percentage of NRF2 mutation (> 50%), suggesting that mutation of this gene provides a selective advantage towards progression to HCC. Finally, preliminary studies in a subset of KRT-19 positive human HCCs, which are known to exhibit the worse prognosis, showed the presence of NRF2 mutations in a very high percentage (55%) of tumors. On the opposite, no mutations were detected in KRT-19 negative human HCCs.

Conclusion: Our results demonstrate that mutations of NRF2 are highly frequent in a subset of human HCCs (KRT-19+) characterized by poor prognosis. Moreover, the findings stemming from the multistage carcinogenic rat model demonstrate that NRF2 mutation is a very early event, suggesting that dysregulation of the NRF2-Keap1 pathway is likely essential for the clonal expansion of KRT-19+ preneoplastic hepatocytes to HCC.

Citation Format: Patrizia Zavattari, Andrea Perra, Marta A. Kowalik, Maddalena M. Angioni, Silvia Menegon, Annalisa Petrelli, Luca Quagliata, Giovanna M. Ledda-Columbano, Luigi Terraciano, Silvia Giordano, Amedeo Columbano. NRF2 mutations are frequent in early rat preneoplastic hepatic lesions and in human hepatocellular carcinomas positive for the stem/progenitor cell marker KRT-19. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1399. doi:10.1158/1538-7445.AM2014-1399
Abstract 1401: Transcription of angiogenin and ribonuclease 4 is regulated by RNA polymerase III elements and a CTCF-dependent intragenic chromatin loop
Authors: Sheng Jinghao , Luo Chi , Jiang Yuxiang , Hinds Philip W. , Xu Zhengping , Hu Guo-fu
Published: May 2015

Angiogenin (ANG) and ribonuclease 4 (RNASE4), two members of the secreted and vertebrate-specific ribonuclease superfamily, play important roles in cancers and neurodegenerative diseases. The ANG and RNASE4 genes share the same promoters but their structure and regulation are unknown. We have characterized the promoters, defined the transcription start site, and identified a mechanism of transcription regulation that involves both RNA polymerase III (Pol III) elements and CCCTC-binding factor (CTCF) sites. We found that two Pol III elements within the promoter regulate ANG and RNASE4 expression in a position- and orientation-dependent manner. We also provide evidence for the presence of an intragenic chromatin loop between the two CTCF binding sites located in two introns flanking the ANG coding exon. We found that formation of this intragenic loop preferentially enhances ANG transcription. These results suggest a multilayer transcriptional regulation of ANG and RNASE4 gene locus. These data also add more direct evidence to the notion that Pol III elements are able to directly regulate Pol II gene transcription. Furthermore, our data indicate that a CTCF-dependent chromatin loop is able to differentially regulate transcription of genes that share the same promoters.

Citation Format: Jinghao Sheng, Chi Luo, Yuxiang Jiang, Philip W. Hinds, Zhengping Xu, Guo-fu Hu. Transcription of angiogenin and ribonuclease 4 is regulated by RNA polymerase III elements and a CTCF-dependent intragenic chromatin loop. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1401. doi:10.1158/1538-7445.AM2014-1401
Abstract 1403: TRIM16 inhibits cell growth through direct interaction and modulation of TDP43 protein stability in cancer cells
Authors: Kim Patrick Y. , Tan Owen , Trahair Toby , Liu Tao , Marshall Glenn M. , Cheung Belamy B.
Published: May 2015

The tripartite motif (TRIM) family of proteins are involved in a diverse range of cellular processes ranging from innate immunity, oncogenesis as well as tumor suppression. A majority of these reported functions occur through protein-protein interactions. Previously, we have found a strong correlation between loss of TRIM16 expression and disease progression in three human cancers: neuroblastoma, squamous cell carcinoma and melanoma. Moreover, our studies have shown that TRIM16 acts as a tumor suppressor in these cancers through effects on cell cycle and migration. In order to better understand the mechanism of TRIM16 in cancer cell growth inhibition, we have identified a novel binding partner of TRIM16 and investigated the functional outcome of the protein-protein interaction. Using the yeast two-hybrid screening tool, we identified transactive response DNA-binding protein 43 (TDP43) as a novel TRIM16 binding protein. TDP43 has been described as a RNA/DNA binding protein with a putative role in HIV transcription and reports also suggest that this protein plays a role in a wide range of neurodegenerative diseases. Through co-immunoprecipitation studies, we have demonstrated that TDP43 directly binds to TRIM16 in human BE(2)-C neuroblastoma and MCF7 breast cancer cells. Enforced over-expression of TRIM16 increased the protein half-life of TDP43. We have also shown that TDP43 expression was required for TRIM16 induced inhibition of neuroblastoma and breast cancer cell growth. Moreover, we have shown that two cell cycle regulatory proteins, E2F1 and pRb, were regulated by TRIM16 and TDP43. Taken together, our studies suggest that the novel mechanism by which TRIM16 inhibits cancer cell growth is through the direct interaction and up-regulation of TDP43 protein expression and with consequent effects on E2F1 and phos-Rb.

Citation Format: Patrick Y. Kim, Owen Tan, Toby Trahair, Tao Liu, Glenn M. Marshall, Belamy B. Cheung. TRIM16 inhibits cell growth through direct interaction and modulation of TDP43 protein stability in cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1403. doi:10.1158/1538-7445.AM2014-1403
Abstract 1404: An EGFR-Stat3-IL6 pathway contributes to NF1 tumor initiation and maintenance
Authors: Wu Jianqiang , Ratner Nancy
Published: May 2015

Neurofibromas are incurable peripheral nerve tumors characteristic of Neurofibromatosis type 1. Development of effective neurofibroma therapies has been hindered by limited understanding of mechanisms underlying neurofibroma formation and growth. We used unbiased insertional mutagenesis screening to identify genes and signaling pathways that drive neurofibroma initiation and growth, and identified Stat3. Immunohistochemistry confirmed phosphorylated STAT3(P-Y705) in all human and mouse neurofibromas. Targeted genetic deletion of Stat3 in Schwann cell precursors (SCPs) and Schwann cells (SCs) significantly delayed neurofibroma formation, and in vitro analysis identified a role for Stat3 in SCP self-renewal and tumor initiation after xenografting. In vivo gain- and loss-of-function studies identified EGFR as the major upstream regulator of SCP P-Stat3. Downstream of P-Stat3, EGFR+ SCPs secreted IL-6, which activated SCPs and mature neurofibroma Schwann cells. Therefore, Stat3 plays a critical role in early SC lineage cells, promoting neurofibroma initiation. Jak/Stat might also play a role in neurofibroma maintenance, as a pharmacological Jak2/Stat3 inhibitor reduced Schwann cell and neurofibroma growth. The data support Jak/Stat as a novel neurofibroma driver pathway and JAK/STAT inhibition as a potential neurofibroma therapeutic strategy.

Citation Format: Jianqiang Wu, Nancy Ratner. An EGFR-Stat3-IL6 pathway contributes to NF1 tumor initiation and maintenance. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1404. doi:10.1158/1538-7445.AM2014-1404
Abstract 1407: The influence of EWS-FLI1 on the Rho/Actin/MRTF circuit in Ewing sarcoma
Authors: Katschnig Anna M. , Schwentner Raphaela , Niedan Stephan , Kauer Maximilian O. , Lawlor Elizabeth R. , Aryee Dave N.T. , Kovar Heinrich
Published: May 2015

Ewing sarcoma (ES) is the second most common bone tumor in children and adolescents. The disease is characterized by the expression of the aberrant transcription factor EWS-FLI1, which is a fusion gene product originating from the chromosomal translocation t(11;22)(q24;q12). Despite good treatment outcomes for patients with localized ES, about 25% of patients already harbor metastatic disease upon presentation and are prevalently faced with poor overall survival. The metastatic cascade is a complex process. Remodeling of the actin cytoskeleton is the first step for a cell in order to acquire a migratory phenotype. The major regulator of the actin cytoskeleton is the Rho family of GTPases, which upon G-protein coupled receptor (GPCR) signaling gets activated and promotes the polymerization of monomeric G-actin into stress fibers. Concurrently G-actin releases the myocardin-related transcription factor family (MRTF) of transcriptional coactivators. MRTFs translocate into the nucleus where they, together with the transcription factor serum response factor (SRF), bind to serum response elements (SRE) in the promoter of genes involved in cell adhesion, migration and motility. However, the ternary complex factor (TCF) family, a class of transcriptional coactivators activated through Ras signaling, can compete with MRTFs for SRF complexing and binds to ets-motifs on SRE. The ets-transcription factor EWS-FLI1 has been shown to substitute for TCFs, potentially interfering with SRF target gene expression. We therefore hypothesize that EWS-FLI1 interferes with GPCR downstream signaling by competition with MRTFs. By gene expression profiling, we show that several putative MRTF target genes are repressed in the presence of EWS-FLI1 in ES cell lines and are strongly induced upon EWS-FLI1 knockdown. Using the MRTFA target gene transgelin (TAGLN) as an example, we show that knockdown of MRTFA can only reduce its serum inducibility in the absence but not in the presence of EWS-FLI1 supporting our hypothesis of EWS-FLI1 perturbing GPCR signaling in ES. With this study we want to elucidate the role of EWS-FLI1 in the regulation of early steps of the metastatic process in ES.

Supported by the Liddy Shriver Sarcoma Initiative.

Citation Format: Anna M. Katschnig, Raphaela Schwentner, Stephan Niedan, Maximilian O. Kauer, Elizabeth R. Lawlor, Dave N.T. Aryee, Heinrich Kovar. The influence of EWS-FLI1 on the Rho/Actin/MRTF circuit in Ewing sarcoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1407. doi:10.1158/1538-7445.AM2014-1407
Abstract 1408: p53-directed translational control can shape and expand the universe of p53 target genes
Authors: Zaccara Sara , Tebaldi Toma , Ciribilli Yari , Bisio Alessandra , Inga Alberto
Published: May 2015

Several genome-wide transcriptome analyses that focused on p53-induced cellular responses in many cellular contexts have continued to expand the already vast p53-regulated transcriptional networks. To investigate post-transcriptional controls as an additional dimension of p53-directed gene expression responses we performed translatome analysis by polysomal profiling on MCF7 cells treated with Doxorubicin and Nutlin-3a. A comparison between the transcriptome and the translatome revealed a considerable level of uncoupling, meaning genes whose transcription did not correlate with translation. Interestingly, this genes category was significantly associated to apoptosis, DNA and RNA metabolism as well as cell cycle functions, suggesting that post-transcriptional control can modulate classical p53-regulated responses. Furthermore, even for well-established p53 targets that were differentially expressed both at transcriptional and translational levels, quantitative differences between transcriptome, subpolysomal and polysomal RNAs were evident. Seeking mechanisms underlying gene expression uncoupling, we identified p53-dependent modulation of five RNA binding proteins where hnRNPD (AUF1) and CPEB4 are direct p53 transcriptional targets and SRSF1, DDX17, YBX1 are indirect targets modulated at translational level in a p53-directed manner. In particular, YBX1 translation appeared to be reduced by p53 via two different mechanisms, one related to mTOR inhibition and the second to miR-34a expression. Overall, we establish p53 as a master regulator of translational control and identify new p53 target genes affecting translation that can contribute to p53-dependent cellular responses.

Citation Format: Sara Zaccara, Toma Tebaldi, Yari Ciribilli, Alessandra Bisio, Alberto Inga. p53-directed translational control can shape and expand the universe of p53 target genes. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1408. doi:10.1158/1538-7445.AM2014-1408
Abstract 1410: Gnaq/11 mutant uveal melanoma is susceptible to Brd4 inhibition by JQ1
Authors: Ambrosini Grazia , Schwartz Gary K.
Published: May 2015

Uveal melanoma (UM) represents the most common intraocular malignancy in the United States, and there are no effective treatments for this aggressive disease. Uveal melanoma is characterized by oncogenic mutations in Gnaq and Gna11, which activate the mitogen-activated protein kinase pathway (MAPK). Furthermore, both primary and metastatic UM are characterized by genetic abnormalities, including the amplification of the chromosomal arm 8q and monosomy of chromosome 3, which are significantly associated with poor prognosis. The oncogene MYC, which is located on 8q24.1, is amplified in nearly 70% of uveal melanoma, and is also regulated by the MAPK pathway. Chromatin regulators have become attractive targets for cancer therapy. In particular, the BET-bromodomain inhibitor JQ1 has shown selective inhibition of c-Myc expression, followed by the suppression of c-Myc-dependent target genes. We examined the effects of JQ1 in a panel of 8 UM cell lines, including cell lines with Gnaq/Gna11 mutations (92.1, Omm1.3, Mel270, Mel202, Omm1), a cell line with MYC amplification (Mel290), and cells without either mutation or amplification (C918, Mel285). The Gnaq/Gna11 mutant cells were the most sensitive to growth inhibition at nanomolar concentrations of JQ1 (IC50=200nM), followed by the cell line with amplified MYC (IC50=1μM), while the cells without mutation or amplification exhibited little inhibition. We also examined the biochemical effects of JQ1 treatment, which caused a dose- and time-dependent suppression of c-Myc as well as survivin, XIAP, ERK1 and E2F1, while p21and the pro-apoptotic protein Bim were induced in all the cell lines. Interestingly, JQ1 also suppressed the anti-apoptotic protein Bcl-xL and induced PARP cleavage only in the Gnaq/Gna11 mutant cells. Flow cytometric analysis indicated a cell cycle arrest in G1 in all the cell lines and an apoptotic population in sub-G1in the mutant cells. Furthermore, treatment with JQ1 resulted in significant antitumor activity in mouse xenograft models of uveal melanoma with Gnaq mutation. All together, these observations support the evidence that JQ1 represent a promising therapeutic approach for uveal melanoma with Gnaq/Gna11 mutations.

Citation Format: Grazia Ambrosini, Gary K. Schwartz. Gnaq/11 mutant uveal melanoma is susceptible to Brd4 inhibition by JQ1. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1410. doi:10.1158/1538-7445.AM2014-1410
Abstract 1411: Regulation of osteoprotegerin expression in breast cancer cells by nuclear factor-kappaB
Authors: Weichhaus Michael , Connelly Linda
Published: May 2015

Acquisition of osteoprotegerin (OPG) expression by breast epithelial cells appears to be linked to the formation of malignant breast neoplasia. Previous in vitro studies demonstrate that OPG expression by breast cancer cells increases resistance to tumor necrosis factor related apoptosis inducing ligand (TRAIL) mediated apoptosis, suggesting a tumor promoting role for OPG. Recently we have observed reduced ability to metastasize in the chick embryo model by MDA-MB-231 breast cancer cells after reducing OPG expression using RNAi methods, further substantiating a tumor promoting role of OPG.

In order to direct inhibitory strategies, we investigated the regulation of OPG expression in human breast cancer cell lines. Based on regulation of OPG in other cell types, we hypothesized that OPG expression is regulated by the transcription factor Nuclear Factor-kappaB (NF-kappaB).

OPG expression was examined in MDA-MB-231 (basal, triple negative), MCF-7 (luminal, ER-positive) and SK-BR-3 (HER-2 positive) breast cancer cells. We used real time RT-PCR and ELISA to confirm that all cell lines expressed OPG mRNA and protein, respectively. NF-kappaB activity was modulated using thymoquinone (TQ; 10 µM) and BMS345541 (1 µM; both inhibitors) and Tumor Necrosis Factor-alpha (TNF-alpha) and Interleukin-1-beta (IL-1-beta; 10 ng/ml, both activators). Specificity for these modulators was determined by NF-kappaB promoter driven luciferase reporter assay.

In MDA-MB-231 cells, inhibition of NF-kappaB lowered basal levels of OPG mRNA and protein expression, suggesting constitutive NF-kappaB activity plays a role in OPG expression. TNF-alpha and IL-1-beta treatment increased OPG mRNA and protein expression significantly above basal levels. Inhibition of NF-kappaB ameliorated TNF-alpha and IL-1-beta induced OPG expression to baseline. In MCF-7 and SK-BR-3 cells, basal levels of OPG mRNA and protein expression were not reduced by the NF-kappaB inhibitors. TNF-alpha and IL-1-beta treatment increased OPG mRNA and protein expression significantly above baseline, however inhibition of NF-kappaB did not ameliorate the induction of OPG mRNA and protein expression.

Our data suggests that the mechanisms regulating OPG expression in breast cancer cells may depend on breast cancer subtype. It appears in the basal cell line, MDA-MB-231, NF-kappaB's tumor promoting effects may be modulated in part by increasing OPG expression. The regulation of OPG expression in cells from other breast cancer subtypes requires further investigation.

Citation Format: Michael Weichhaus, Linda Connelly. Regulation of osteoprotegerin expression in breast cancer cells by nuclear factor-kappaB. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1411. doi:10.1158/1538-7445.AM2014-1411
Abstract 1412: Capturing c-Myb target genes in adenoid cystic carcinoma
Authors: BRAYER KATHRYN , Ness Scott
Published: May 2015

Mutated versions of c-Myb are potent oncoproteins, and Myb proteins are over- or highly-expressed in a wide variety of human tumors. Adenoid Cystic Carcinoma (ACC), the second most frequent malignancy of minor and major salivary glands, frequently contains a recurrent t(6;9) translocation which fuses the c-Myb proto-oncogene on chromosome 6q to the NFIB gene on chromosome 9p resulting in the expression of novel Myb-NFIB fusion oncoproteins. These variants of c-Myb play a definitive role in development of ACC tumors, and are the first evidence that Myb proteins function as “driver” mutations in human cancer. Identifying target genes directly regulated by Myb-NFIB oncoproteins in ACC tumors can help determine how Myb proteins transform cells and contribute to tumor development in ACC.

Genomics analyses of solid tumors is challenging because tumors are often heterogeneous tissue types and are often not stored in a manner that preserves labile nucleic acids. FFPE samples offer the most promise since formaldehyde fixation effectively “locks” the Myb-NFIB fusion proteins and epigenetic marks, such as modified histones, to the genes of interest. We have developed improved methods were for extracting chromatin from FFPE samples for use in chromatin immunoprecipitation coupled with next-generation sequencing (ChIP-seq) and are applying these technical innovations to ACC tumors preserved in FFPE. When combined with gene expression information provided by RNA-seq analysis, ChIP-seq analysis of c-Myb gene targets will identify regulators that can be targets in novel therapeutic strategies in the future, as well as provide a greater understand of c-Myb functions in ACC and other epithelial tumors in which Myb plays a role.

Citation Format: KATHRYN BRAYER, Scott Ness. Capturing c-Myb target genes in adenoid cystic carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1412. doi:10.1158/1538-7445.AM2014-1412