bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2790: PRC2 mediated repression of SMARCA2 predicts for EZH2 inhibitor activity in tumors with SWI/SNF mutations
Authors: Januario Thomas , Ye Xiaofen , Bainer Russell , Alicke Bruno , Solon Margaret , Haley Benjamin , Modrusan Zora , Gould Stephen , Koeppen Hartmut , Yauch Robert L.
Published: July 2017

A synthetic lethality caused by EZH2 inhibition in the context of SNF5 mutations is supported by both preclinical and recent clinical data, however the extent of the synthetic lethal relationship in the context of other SWI/SNF subunit mutations is not well understood. We determined that a subset of SMARCA4 mutant cancer models are sensitive to EZH2 inhibition. EZH2 inhibition resulted in a heterogenous phenotypic response characterized by senescence and/or apoptosis amongst models, and further lead to tumor growth inhibition in vivo. The differential sensitivity to EZH2 inhibition was not caused by a differential pharmacodynamic effect of the drug, nor differences in basal histone methylation or PRC2 subunit levels. However, expression of the SWI/SNF subunit, SMARCA2, delineated sensitivity amongst SMARCA4 mutant models tested. Expression of SMARCA2 further delineated sensitivity amongst other SWI/SNF mutant models tested, including SNF5 and ARID1A mutants. We determined that SMARCA2 is under PRC2 mediated suppression and the derepression of SMARCA2 was necessary for apoptosis, but not senescence, in response to EZH2 inhibition. SMARCA2 has been shown to be concurrently lost in a high percentage of SNF5 mutant malignant rhabdoid tumors and SMARCA4 mutant SCCOHT tumors, however we determined that ≈15% of SMARCA4 mutant NSCLCs concurrently lose SMARCA2. Our data supports monitoring SMARCA2 expression as a predictive biomarker for EZH2-targeted therapies that are currently being developed in the context of SWI/SNF mutant cancers.

Citation Format: Thomas Januario, Xiaofen Ye, Russell Bainer, Bruno Alicke, Margaret Solon, Benjamin Haley, Zora Modrusan, Stephen Gould, Hartmut Koeppen, Robert L. Yauch. PRC2 mediated repression of SMARCA2 predicts for EZH2 inhibitor activity in tumors with SWI/SNF mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2790. doi:10.1158/1538-7445.AM2017-2790
Abstract 2803: The NCI mouse repository: Cancer models and miRNA-ES cell resource
Authors: Awasthi Parirokh , Debra Fitzgerald , Stephen Jones N.
Published: July 2017

The NCI Mouse Repository, located at the Frederick National Laboratory for Cancer Research (FNLCR), Frederick, Maryland, is an NCI-funded resource of approximately 150 genetically-engineered mouse cancer models and associated strains, including mice bearing conditional and point-mutant alleles in cancer-related genes. In addition, the Repository houses a unique collection of over 1500 different mouse ES cell clones bearing conditionally-activated miRNA transgenes to facilitate in vivo exploration of miRNA functions. The NCI Mouse Repository makes strains and mESCs available to all members of the scientific community (academic, non-profit, and commercial). The mouse models and ES cell clones are cryo-archived and distributed as frozen germplasm or cells.

Requests may be placed through the NCI Mouse Repository website (https://ncifrederick.cancer.gov/Lasp/MouseRepository/Default.aspx). In addition to the request form, this website includes detailed description for each strain accepted into the Repository and the associated publications provided by the donating scientist. The miR-harboring ESCs, originally generated at the Cold Spring Harbor Laboratories for the NCI, are described in full detail and include validation data for each miRNA ES cell clone. These resources are available for nominal cost to NCI, NIH, and other US government-funded investigators, as well as to Investigators at non-profit organizations.

Citation Format: Parirokh Awasthi, Fitzgerald Debra, Jones N. Stephen. The NCI mouse repository: Cancer models and miRNA-ES cell resource [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2803. doi:10.1158/1538-7445.AM2017-2803
Abstract 2816: The Jackson Laboratory Repository: Mouse models for cancer research
Authors: Boswell Deborah , Rockwood Stephen , Sasner Michael , Team The JAX Repository
Published: July 2017

The mouse is a well-established model organism for research of the biology, prevention, diagnosis, and treatment of cancer. Among the advantages of this valuable biomedical research tool are a relatively short reproductive cycle, an accelerated lifespan, and the ease of genetic manipulation and modification. Serving as a resource to the scientific community, the JAX Repository collection encompasses over 10,000 mouse strains and acquires hundreds of new models each year. Some of these new models are highlighted in this poster. Many of these strains have applications for modeling human cancer, including genetically engineered mouse models for specific cancers and xenograft models. Research tool strains, such as cas9-expressing (CRISPR) lines, a suite of immunodeficient mice, and recombinase expressing strains, are available to investigators to generate customized mutant lines for specialized purposes. JAX offers supplementary research tools that include specialized strain platforms and other useful resources. The JAX patient-derived xenograft (PDX) cancer model resource leverages the immunodeficient NSG strain for tumor engraftment.

The Repository maintains a searchable online resource to find mice (www.jaxmice.jax.org) and an Oncology Therapeutic Area page (www.jax.org/jax-mice-and-services/solutions-by-therapeutic-area/oncology) as a launch pad to featured JAX strains and resources related to oncology research.

The Repository has a rigorous quality control program that inspects and confirms expected mutation identity and genetic background. JAX mouse lines are also screened for alleles (GFP, cre, lacZ, etc.) that may contaminate strains in mouse lines shared between labs—an underappreciated problem that may contribute to inconsistencies of reproducibility. In addition, the Reproductive Sciences group at JAX safeguards each strain by cryopreservation, and can create cohorts for studies rapidly using IVF technology. Researchers can submit their strains to be considered for inclusion in the Repository by using the on-line form available at The Jackson Laboratory website: www.jax.org/donate-a-mouse.

The Jackson Laboratory Repository is supported by the NIH, The Howard Hughes Medical Institute, and other private charitable foundations.

Citation Format: Deborah Boswell, Stephen Rockwood, Michael Sasner, The JAX Repository Team. The Jackson Laboratory Repository: Mouse models for cancer research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2816. doi:10.1158/1538-7445.AM2017-2816
Abstract 2832: Class I histone deacetylase inhibitors impair tumor growth and metastatic programs
Authors: Krämer Oliver H. , Kiweler Nicole
Published: July 2017

(a) introductory sentence indicating the purposes of the study

Metastasis formation is associated with poor patient prognosis. Epithelial-mesenchymal and mesenchymal-epithelial (EMT/MET) transition cycles are key for the formation, survival, and homing of metastatic cells. Inhibitors against epigenetic modulators of the histone deacetylase family (HDACi) are promising, clinically tested epigenetic drugs that may combat cancer proliferation and spread.

(b) brief description of pertinent experimental procedures

We chose a systems toxicology approach to analyze the relevance of HDACs and their inhibitors for metastatic cell growth. We combined in vivo tests with morphological, cellular, functional, and global proteomic analyses. This strategy follows the 3R principle by Russel and Burch. Of the four classes of HDACs (I-IV), the class I subgroup is most important for tumorigenesis. We therefore analyzed how the pharmacological inhibition of class I HDACs affects the growth and spreading of syngeneic kidney cancer cells into the lungs of BALB/c mice and how such drugs affect tumor cell growth, apoptosis, migration, and gene expression patterns controlling EMT/MET in transformed kidney and breast cells. Furthermore, we investigated how the genetic elimination of HDACs affects cancer cell growth and EMT/MET. We used flow cytometry, immunoblot, immunofluorescence, qPCR, proteomics on a global scale, RNAi against the class I HDACs HDAC1/HDAC2, and in vivo tumor analyses.

(c) summary of the new, unpublished data

Both the inhibition as well as the elimination of HDAC1/HDAC2 evokes growth arrest, morphological alterations, and apoptosis. HDACi block tumor cell migration, integrin-dependent cell adhesion, and EMT induced by the cytokine TGF-β. Global proteomics and qPCR analyses illustrate that HDACi disrupt EMT/MET cycles and metastatic spread. Moreover, these assays reveal pathways through which HDACi propel cancer cell apoptosis.

(d) statement of the conclusions

Class I HDACi can modulate the EMT/MET balance that is required for the detrimental process of metastasis. Hence, HDACi should be considered further as clinical treatment option.

Citation Format: Oliver H. Krämer, Nicole Kiweler. Class I histone deacetylase inhibitors impair tumor growth and metastatic programs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2832. doi:10.1158/1538-7445.AM2017-2832
Abstract 2836: Mitochondrial genomic backgrounds differentially affect nuclear DNA methylation and gene expression
Authors: Vivian Carolyn J. , Brinker Amanda E. , Graw Stefan , Koestler Devin C. , Legendre Christophe , Gooden Gerald C. , Salhia Bodour , Welch Danny R.
Published: July 2017

Accumulating data implicate mitochondrial genetics and metabolism as contributors to metastatic efficiency. With only 13 proteins encoded by the mtDNA genome, the mechanism(s) by which the coordination of multiple genes involved in metastasis could occur is unclear. We hypothesized that mitochondrial DNA (mtDNA) polymorphisms would differentially regulate nuclear DNA (nDNA) methylation and gene expression. To test the hypotheses, we created Mitochondrial Nuclear Exchange (MNX) mice, by transferring an oocyte nucleus from strainx into an enucleated oocyte from strainy. The mice show that mammary tumor formation and metastasis are regulated by inherited mitochondrial polymorphisms (PMID: 26471915). Age-matched, male mouse brains were collected and pooled from four litter mates representing each of the wild-type and MNX mice (8 groups). Genome-wide nDNA methylation (Mouse methyl-Seq) and gene expression (RNA-Seq) were measured and results validated in independent replicate samples. Significant, selective and reproducible differential DNA methylation and gene expression were observed and validated between strains having identical nDNA, but different mtDNA. While the signal(s) from mitochondria altering methylation is not fully defined, the findings support the hypothesis and demonstrate how mitochondrial genetic alterations could be one of several quantitative trait loci involved in complex phenotypes, such as metastasis. The results also suggest that mtDNA polymorphisms could serve as predictive biomarkers for cancer aggressiveness. Support: Susan G. Komen for the Cure (SAC11037), Natl Fndn Cancer Res, Biomedical Research Training Program, Kansas Bioscience Authority, CA134981, P30-CA168524.

Citation Format: Carolyn J. Vivian, Amanda E. Brinker, Stefan Graw, Devin C. Koestler, Christophe Legendre, Gerald C. Gooden, Bodour Salhia, Danny R. Welch. Mitochondrial genomic backgrounds differentially affect nuclear DNA methylation and gene expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2836. doi:10.1158/1538-7445.AM2017-2836
Abstract 2841: Investigating drivers of disease progression in invasive lobular carcinoma
Authors: Tasdemir Nilgun , Sikora Matthew , Li Zhu , Levine Kevin , Basudan Ahmed , Luthra Soumya , Elishaev Esther , Chandran Uma , Tseng George C. , Jankowitz Rachel , Dabbs David J. , McAuliffe Priscilla , Davidson Nancy E. , Oesterreich Steffi
Published: July 2017

Invasive lobular carcinoma (ILC) is the second most common type of breast cancer following invasive ductal carcinoma (IDC) and accounts for 10-15% of all cases. Unlike the masses or lumps formed by IDCs, ILCs grow as small, dis-cohesive cells in a single-file pattern within dense layers of extracellular matrix. Paradoxically, while patients with ILC display favorable prognostic and predictive factors (ER+, PR+, HER2-, low Ki67), their long-term response to endocrine therapy is worse than patients with IDC. Despite such histological and clinical differences, ILC has remained a gravely understudied subtype of breast cancer. Thus, there is urgent need to investigate molecular drivers of ILC progression in order to develop more effective therapeutic strategies and improve patient outcome. To this end, we used the Nanostring platform to measure the expression of 577 copy number variation-associated genes in 131 primary ILC tumors and identified two candidate drivers that exhibit higher expression in tumors from patients with recurrent versus non-current disease: CTTN (cortical actin binding protein) and QSOX1 (quiescin sulfhydryl oxidase). In follow-up studies, we observed high CTTN and QSOX1 expression in human ILC cell lines, tumors and patient-derived xenografts. In addition, QSOX1 expression was further increased in ILC ovarian metastases compared to their matched primary tumors. In functional in vitro studies, RNAi-mediated inhibition of CTTN led to decreased adhesion and haptotaxis to Collagen I, while QSOX1 knockdown diminished the growth of human ILC cell lines. We are currently assessing the in vivo therapeutic utility of CTTN and QSOX1 inhibition in tumor growth and metastasis using human ILC cell line and patient-derived xenograft mouse models. This study greatly advances our understanding of ILC disease mechanisms and identifies novel therapeutic targets towards improving the clinical outcome of patients with this understudied subtype of breast cancer.

Citation Format: Nilgun Tasdemir, Matthew Sikora, Zhu Li, Kevin Levine, Ahmed Basudan, Soumya Luthra, Esther Elishaev, Uma Chandran, George C. Tseng, Rachel Jankowitz, David J. Dabbs, Priscilla McAuliffe, Nancy E. Davidson, Steffi Oesterreich. Investigating drivers of disease progression in invasive lobular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2841. doi:10.1158/1538-7445.AM2017-2841
Abstract 2844: Identification of genes associated with pancreatic cancer metastasis by genome-wide CRISPR Cas9 screening
Authors: Li Youjia , Feng Huiyi , Liu Guangjie , Wong Chi Hin , Li Chi Han , Chen Yangchao
Published: July 2017

Pancreatic cancer is an extremely lethal cancer with a 5-year survival rate of 7%. One major reason why pancreatic cancer is hard to treat is its metastasis nature. Genes that related to the tumorigenesis and progression of pancreatic cancer were identified after decades of efforts. Several researches had revealed that pancreatic cancer originated from the successive accumulation of gene mutations, especially KRAS2, CNKD2A, TP53 and SMAD4. However, little is known about genes that regulate pancreatic cancer metastasis. Here we used a genome wide CRISPR Cas9 screening to identify the gene(s) associated with the metastasis of pancreatic cancer. We transduced pancreatic cancer cell line with lentivirus-based genome wide CRISPR sgRNA library to establish mutated cell library, and orthotopically injected the cell library into nude mice and waited for primary tumor growth and metastasis, then collected primary and metastatic tumors after several months. By next generation sequencing and analysis, we identified some gene candidates which may play important roles on pancreatic cancer metastasis.

Note: This abstract was not presented at the meeting.

Citation Format: Youjia Li, Huiyi Feng, Guangjie Liu, Chi Hin Wong, Chi Han Li, Yangchao Chen. Identification of genes associated with pancreatic cancer metastasis by genome-wide CRISPR Cas9 screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2844. doi:10.1158/1538-7445.AM2017-2844
Abstract 2847: Loss of heterozygosity (LOH) within the hypoxia inducible factor 3A (HIF3A) locus in liver metastasis (LM) from primary colorectal cancer (CRC)
Authors: Kitajima Takahito , Koi Minoru , Worix Alexander , Carethers John M.
Published: July 2017

Background and Aims: HIF3α is a hypoxia-regulated transcription factor that represses the effects of HIF1α and HIF2α under hypoxia at transcriptional and posttranslational levels. We previously found that LOH at the HIF3A locus is frequent in LM (59%) and the expression of HIF3A protein is reduced in LM compared to primary CRC. At present, the smallest overlapping LOH (SOL-LOH) region has been mapped to the intron 8 of the HIF3A, spanning from 46,312,911 to 46,315,651 on chromosome 19 in LMs. This genomic region contains multiple FOXA1 binding sites embedded in the two DNase I hypersensitive sites (UCSC Genome Browser, https://genome.UCSC.edu). About 30% of the human population carries a deletion within our SOL-LOH region (1000 Genomes Consortium: esv3644527, Chr19: 46,314,109-46,315,478). In this study, we determined whether esv3644527 deletion affects on the expressions of HIF3A, HIF2A, HIF1A and their target genes under normoxic and hypoxic conditions.

Methods: For LOH mapping, 75 resected LMs derived from primary CRC were analyzed for LOH using 8 polymorphic markers. We obtained three EBV-transformed B cell lines with heterozygous esv3644527 deletion and the one with the homozygous deletion from the Coriell Institute. The expression levels of 23 genes related to HIF pathways were determined by qRT-PCR.

Results and Discussion: The expression levels of HIF3A mRNA were too low to compare among these B cell lines by qRT-PCR. However, the expression levels of HIF2A and its target gene, angiopoietin 2 (ANGPT2), are significantly elevated in B cells with a homozygous deletion compared to B cells with a heterozygous deletion under both normoxic and hypoxic conditions. These observations are compatible with the results obtained from a previous study where pulmonary endothelial cells from HIF3A-knockout mice expressed elevated levels of HIF2A and ANGPT2 (Kobayashi-S et al., Genes Cells, 2015, 20:224-241), suggesting that deletion of the FOXA1 sites present in this region may regulate the HIF3A expression.

Conclusions: Our results show that about 60% of LMs exhibit LOH in the 2.7 Kb region surrounding intron 8 of the HIF3A locus. Deletion within this region may lead to upregulation of HIF2A and ANGPT2 by negatively regulating HIF3A expression. To prove our hypothesis, colon cancer cell lines with deleted FOXA1 sites will be assessed.

Citation Format: Takahito Kitajima, Minoru Koi, Alexander Worix, John M. Carethers. Loss of heterozygosity (LOH) within the hypoxia inducible factor 3A (HIF3A) locus in liver metastasis (LM) from primary colorectal cancer (CRC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2847. doi:10.1158/1538-7445.AM2017-2847
Abstract 2848: Identifying and targeting competing endogenous RNA (ceRNAs) networks to inhibit lung metastasis in triple negative breast cancer
Authors: Ersan Pelin , Tokat Unal , Eyupoglu Erol , Raza Umar , Riazalhosseini Yasser , Alkan Can , Thieffry Denis , Gautheret Daniel , Sahin Ozgur
Published: July 2017

Introduction: Triple negative breast cancer (TNBC), the most aggressive breast cancer subtype, has high incidence rate of lung metastasis. Not only protein coding transcripts, but also non-coding transcriptome, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), have active roles in cancer progression and metastasis. Additionally, lncRNAs can act as sponges for miRNAs. Here, we aimed i) to construct the first mRNA-miRNA-lncRNA competing endogenous RNA (ceRNA) network controlling metastasis in TNBC, and ii) to prevent lung metastasis by targeting identified central candidate genes.

Material/Method: We established primary tumor and human-in-mouse (HIM) and mouse-in-mouse (MIM) lung metastasis models using TNBC cell lines in nude and Balb/c mice, respectively. We visualized both primary and metastatic tumors using in vivo imaging system, harvested tumors and performed both RNA and small RNA sequencing. We obtained differentially expressed miRNAs, mRNAs and lncRNAs between primary and metastatic tumors. Using several bioinformatics tools, we did enrichment analyses, miRNA target predictions, and network construction. Identified central lncRNAs were overexpressed or knocked down and will be tested in in vitro and vivo metastasis-related assays.

Results and Conclusions: We obtained 45 and 91 miRNAs which were differentially expressed between primary and metastatic tumors in HIM and MIM models, respectively. A miRNA family with an established role in metastasis as well as several other miRNAs was identified as highly differentially expressed in the same direction in both models. Moreover, 1127 and 3350 mRNAs, and 85 and 111 lncRNAs were differentially expressed in HIM and MIM models, respectively. Metastasis-related processes based on differentially expressed mRNAs were enriched in the data. We then integrated these three layers of data, functional enrichments, pathway maps and target predictions to construct the first ceRNA network controlling lung metastasis in TNBCs. Currently, we are testing the functional roles of candidate lncRNAs in in vitro and in vivo metastasis assays. Ultimately, our study will uncover novel lncRNAs that can be used as potential targets and/or biomarkers in breast-to-lung metastasis.

Funding: This study is supported by TUBITAK-CNRS Bilateral Grant with project number 214S364.

Citation Format: Pelin Ersan, Unal Tokat, Erol Eyupoglu, Umar Raza, Yasser Riazalhosseini, Can Alkan, Denis Thieffry, Daniel Gautheret, Ozgur Sahin. Identifying and targeting competing endogenous RNA (ceRNAs) networks to inhibit lung metastasis in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2848. doi:10.1158/1538-7445.AM2017-2848
Abstract 2849: Identification of active enhancers as potential biomarkers of aggressive colorectal cancer
Authors: Wang Zhiquan
Published: July 2017

Colorectal cancer is the third most common cancer and second leading cause of cancer-related deaths in the United States. Tumor metastasis is the primary cause of mortality. Even with aggressive surgical and therapeutic management approaches, more than one third of patients will develop metastatic disease. Understanding the molecular changes that drive tumor cells to the metastatic state is key to developing targeted therapies and identifying early-stage markers for progression. To identify changes that promote cell invasiveness, a hallmark of tumor progression, we exposed the pre-metastatic SW-480 colorectal cancer cell line to multiple rounds of selection for the capacity to invade through a synthetic extra-cellular matrix. Following repeated selection, invasiveness increased by more than 10-fold. Epithelial markers, such as E-cadherin, were repressed and markers commonly associated with tumor cells that have undergone epithelial-mesenchymal transition, such as N-cadherin and Vimentin, were upregulated. Likewise, invasive cells showed increased affinity for ECM components. Paired ChIP-seq and RNA-seq revealed likely roles for epigenetic alterations in driving gene expression changes. Furthermore, the epigenetic changes followed ordered patterns of activation and inactivation, suggesting that these epigenetic signatures may provide insight into early mechanisms associated with epithelial-mesenchymal transition. Collectively, our data suggest that early epigenetic markers may be better early predictors of colorectal cancer aggressiveness than gene expression patterns and support the use of this in vitro metastasis model to study the molecular mechanisms of cancer progression.

Citation Format: Zhiquan Wang. Identification of active enhancers as potential biomarkers of aggressive colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2849. doi:10.1158/1538-7445.AM2017-2849
Abstract 2879: Dj-1 confers maintenance of stemness and radioresistance by regulating EGFRvIII expression in glioma stem cells
Authors: Park Myung-Jin , Kim Jeong-Yub , Kim Hee-Jin , Kim Ji-Soo , Kim Jeong-Chul , Lee Dea-Hee , Na Yoo-Jin
Published: July 2017

DJ-1 is involved in many key cellular processes including cell proliferation, transcriptional regulation, differentiation, oxidative stress protection, and mitochondrial function maintenance. Deregulation of DJ-1 has been implicated in the pathogenesis of many human diseases such as Parkinson's disease, amyotrophic lateral sclerosis, infertility, and cancer. DJ-1 was initially identified as an oncogene product involved in human tumorigenesis in numerous cancer types. Alteration in expression of DJ-1 is associated with tumorigenesis in several types of cancers. Herein, we aimed to clarify the effect of DJ-1 on stemness and radioresistance of glioma stem cells (GSCs). Firstly, we found that the reduction in expression of DJ-1 in brain tumor tissues when compared with tumor adjacent normal brain tissues, as indicated by reduced DJ-1 staining. Knock-down of DJ-1 inhibited self-renewal activity of GSCs in vitro as evidenced by neurosphere formation, limiting dilution, and soft agar clonogenic assays. DJ-1 knock-down suppressed maintenance of stemness by suppressing the expression of Notch intracellular domain, Sox2, and phosphorylated STAT3 proteins. Intriguingly, DJ-1 knock-down inhibited the expression of EGFRvIII in GSCs which might be the cause of suppression of stemness pathways. In addition, knockdown of DJ-1 induced apoptosis, reduced cell invasiveness, and sensitized GSCs to ionizing radiation. Based on these data, we propose that DJ-1 could be considered as a crucial diagnostics and therapeutics target for malignant glioma.

Note: This abstract was not presented at the meeting.

Citation Format: Myung-Jin Park, Jeong-Yub Kim, Hee-Jin Kim, Ji-Soo Kim, Jeong-Chul Kim, Dea-Hee Lee, Yoo-Jin Na. Dj-1 confers maintenance of stemness and radioresistance by regulating EGFRvIII expression in glioma stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2879. doi:10.1158/1538-7445.AM2017-2879
Abstract 2903: 1-Methoxyphaseollidin: Novel gamma secretase inhibitor targeting notch-1 signaling in breast cancer stem cells
Authors: Kolluru Venkatesh , Pal Deeksha , Baby Becca , Alatassi Houda , Sharma Arun Kumar , Ankem Murali , Damodaran Chendil
Published: July 2017

We recently showed that two different ALDH+ and CD44+/CD24-/low breast cancer stem cells (BSCSs) exhibited stem cell characteristics that include self-renewal, extensive proliferation, the ability to form non-adherent spherical clusters, chemotherapy resistance and high Notch1 expression. We have identified a compound compound: 6-(3-methylbut-2-enyl) coumestrol (Pso) and treatment with Pso resulted in growth inhibition and an EMT phenotype in both BCSCs and BC cells. Oral Pso administration at physiologically achievable doses (25 mg/kg/BW) suppressed the growth of BCSCs and BC xenografts without toxicity. In the current studies, we identified several novel Pso-derived analogs that may be more potent than the parent compound. One such compound, 1-methoxyphaseollidin (1MP), obtained via three main functional group changes: (i) translocation of the isoprenyl moiety from the phenyl ring fused to the pyran ring (as in Pso) to the phenyl ring adjacent to the furan ring, (ii) removal of the carbonyl group from the pyran ring, and (iii) introduction of a methoxy group at the 1-position, inhibited Notch1 activity and growth of both BSCS and BC cells at nM concentration (IC50: 300nM), which is 100 times more potently than Pso in cell culture models. Molecular studies suggest that 1MP inhibits Notch signaling pathways (Hes1, Hey1 and Presenilin) in both BCSC and BC cells. Further, downregulation of AKT signaling (pAKT (S473), p65 and BCl-2 were seen in 1MP treated cells. Docking studies suggest that 1MP binds outside of the catalytic unit of γ-secretase and induces a conformational change, resulting in Notch1 inhibition in both BCSCs and BC cells. More importantly, administration of 1MP significantly inhibited the growth of BCSC and BC tumors without causing gastrointestinal toxicity in tumor-bearing mice. H&E staining suggests that 1MP treated tumors show infiltrate to margins are less as compared to vehicle treated mice’s. We believe targeting notch1 signaling and optimizing 1MP could be an effective therapeutic strategy for treating breast cancer.

Note: This abstract was not presented at the meeting.

Citation Format: Venkatesh Kolluru, Deeksha Pal, Becca Baby, Houda Alatassi, Arun Kumar Sharma, Murali Ankem, Chendil Damodaran. 1-Methoxyphaseollidin: Novel gamma secretase inhibitor targeting notch-1 signaling in breast cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2903. doi:10.1158/1538-7445.AM2017-2903
Abstract 291: Sequential treatment with the Wee1 inhibitor, AZD1775, enhances the effect of trabectedin in the L-sarcomas
Authors: Musi Elgilda , Ambrosini Grazia , Schwartz Gary K.
Published: July 2017

Soft tissue sarcomas are heterogeneous mesenchymal neoplasms and account for 1% of all cancers in adults. Over 50 sarcomas subtypes have been classified and many have very limited treatment options. Chemotherapies such as doxorubicin, dacarbazine and gemcitabine have had very low response rates. Two of the most common subtypes of sarcomas are liposarcoma and leiomyosarcoma, also referred to as the L-sarcomas. Trabectedin, a marine derived compound from the sea sponge, Ecteinascidia turbinate, has recently been approved for the treatment of L-sarcomas which has shown a modest effect over common therapies. As a DNA damaging agent, we hypothesized that trabectedin would induce a G2 cell cycle arrest and subsequent inhibition of Wee1 would abrogate this cell cycle checkpoint and induce apoptosis. We therefore examined the effects of trabectedin followed by AZD1775, a Wee1 inhibitor, in a panel of 6 sarcoma cell lines including liposarcoma (LS141, DDLS) and leiomyosarcoma (SK-LMS, SK-UT1, SK-UT1b). IC50s concentrations of trabectedin were determined to be between 0.5 to 2nM, while IC50s for AZD1775 were in the range of 100-200 nM. In vitro results have shown an enhanced inhibition of cell viability with combination treatment in all cell lines at concentrations of 1nM trabectedin for 24hrs followed by 100nM AZD1775 for 48hrs. We also examined biochemical effects with sequential drug treatment (24hrs trabectedin followed by 24hrs AZD1775) which presented an increase of cyclin A1 and cyclin B1 indicative of G2 cell cycle arrest along with increase of phospho-H2AX, indicative of DNA damage by trabectedin, while subsequent treatment with the Wee1 inhibitor showed decrease of phosphorylation of CDC2 (Tyr15). Flow cytometric analysis indicated G2/M cell cycle arrest with trabectedin and abrogation of G2/M with AZD1775. These observations correlated with enhanced apoptosis as measured by biochemical PARP cleavage and DNA content (sub-G1 population). Taken together these results provide a foundation for the development of the sequential treatment of trabectedin followed by the Wee1 inhibitor, AZD775, in the L-sarcomas.

Citation Format: Elgilda Musi, Grazia Ambrosini, Gary K. Schwartz. Sequential treatment with the Wee1 inhibitor, AZD1775, enhances the effect of trabectedin in the L-sarcomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 291. doi:10.1158/1538-7445.AM2017-291
Abstract 2915: The timing of mutational burst events impact the growth of tumors in the colon
Authors: Sievers Chelsie K. , Vo Tien N. , Pickhardt Perry J. , Pooler Bryan D. , Matkowskyj Kristina A. , Albrecht Dawn M. , Rosemarie Quincy , Newton Michael A. , Halberg Richard B.
Published: July 2017

Basic and clinical scientists believe that benign polyps in the colon progress to cancers through the slow, stepwise accumulation of mutations. Interestingly, only a small percentage of all tumors progress, whereas a significant number remain static in size, regress, or resolve completely. The mechanisms underlying these differential fates are unknown, and mechanisms of tumor evolution during this premalignant phase are still under investigation and continued debate. We previously reported that sub-clonal diversity arises early in small human adenomas and contributes to the growth of tumors in the colon. An emerging hypothesis is that colorectal tumors form and progress via a process of punctuated equilibrium, where multiple copy number alterations and mutational events happen simultaneously in a burst-like fashion. In this study, we prospectively test this concept using a mouse model in which tumor induction is spatially and temporally controlled via a non-surgical delivery of adenovirus expressing CRE recombinase and a temporally controlled mutational burst via administration of the carcinogen Azoxymethane. Tumors are induced at a similar rate regardless the timing of the burst relative to tumor induction with a mean tumor incidence of 62% at three weeks post induction. However, tumor growth may be affected by the timing of the burst. Animals that had a mutational burst event prior to tumor induction or those that had a late mutational burst event had a lower average in vivo growth rate compared to controls and those with an early burst event, but the average in vivo tumor size was comparable across all groups. Taken together, these preliminary data provide evidence that the timing of a mutational burst event contributes to tumor growth. This prospective experiment is being extended through computer modeling and statistical inference to compare in silico mutational landscapes to a cohort of colon polyps removed from patients at normal screening. The findings will provide new insights into the earliest stages of tumorigenesis.

Citation Format: Chelsie K. Sievers, Tien N. Vo, Perry J. Pickhardt, Bryan D. Pooler, Kristina A. Matkowskyj, Dawn M. Albrecht, Quincy Rosemarie, Michael A. Newton, Richard B. Halberg. The timing of mutational burst events impact the growth of tumors in the colon [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2915. doi:10.1158/1538-7445.AM2017-2915
Abstract 2917: High complexity molecular indexing reveals that time-dependent cell plasticity underpins response to EGFR targeted therapy
Authors: Boudreau Aaron , Bourgon Richard , Evangelista Marie
Published: July 2017

Non-small-cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR)-mutant tumors often receive erlotinib, a 1st generation EGFR inhibitor, as a frontline therapy. Although many patients initially experience positive response with erlotinib treatment, resistance invariably occurs in the majority of cases - however, it remains unclear the full extent by which resistance is pre-determined by genomic aberration, stochastic by potentially epigenetic mechanisms, or a combination thereof. Using a lentiviral DNA barcode library to molecularly index PC-9, an EGFR mutant (exon 19 del. E746-A750) cell line model, we used next-generation DNA sequencing to trace the fate of over 1.6 million individual cells following erlotinib treatment. Similar to previous reports, we show that multiple subpopulations are present in PC-9 cells - those that are exquisitely sensitive to erlotinib, and those that are inherently resistant, representing ~2% of the population. Surprisingly, in the absence of erlotinib treatment, we show that cells cultured over time transitioned between these two states while maintaining population equilibrium. Using mathematical modeling, we identified several parameters of state switching or flux that were required to maintain this dynamic equilibrium. Understanding the molecular basis by which cells maintain cell state plasticity may enable new strategies to limit intra-tumor heterogeneity and may ultimately improve recurrence-free survival in NSCLC following erlotinib therapy.

Citation Format: Aaron Boudreau, Richard Bourgon, Marie Evangelista. High complexity molecular indexing reveals that time-dependent cell plasticity underpins response to EGFR targeted therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2917. doi:10.1158/1538-7445.AM2017-2917
Abstract 2999: NKG2A checkpoint receptor expression on tumor-infiltrating CD8+ T cells restrains efficacy of immunotherapy
Authors: Hall Thorbald van , Montfoort Nadine van , Piersma Sytse , Sluijter Marjolein , Welters Marij J. , André Pascale , Wagtmann Nicolai , Burg Sjoerd H. van der
Published: July 2017

The inhibitory receptor CD94-NKG2A is expressed on subsets of NK cells and cytotoxic CD8+ T cells, but not CD4+ T helper cells. It’s ligand is the non-classical MHC class I molecule HLA-E, commonly over-expressed in human cancers. We previously demonstrated that high HLA-E expression in ovarian carcinoma and NSCLC may neutralize the survival benefit of T cell infiltration, suggesting that NKG2A could represent an immune checkpoint that tumors may exploit for immune evasion. We thus examined NKG2A expression on human and mouse Tumor Infiltrating Lymphocyte (TIL) populations and tested blockade of this receptor in mouse tumor models. Multicolor flow cytometry analysis showed higher frequency of NKG2A+CD8+ T cells in TIL samples obtained from biopsies of human head- and neck- carcinomas (n=17) compared to peripheral blood CD8+ T cells. Frequency of NKG2A+ TIL was higher in patients with measurable immune reactivity to HPV16-viral antigens than in patients without tumor immunity (14.8% vs 4.7%, respectively). Interestingly, only subsets of the NKG2A+ T cells co-expressed other inhibitory receptors, including PD-1 and TIM3, suggesting the existence of a ‘dedicated’ T cell subset for NKG2A. In our mouse tumor models we observed similar findings and, moreover, demonstrated that therapeutic vaccines comprising tumor antigens increased the frequency of NKG2A+-positive CD8+ TIL up to 80%. Similarly, expression of Qa-1, the mouse homologue of HLA-E, on tumor cells also increased after therapeutic vaccination. As a proof of concept that the NKG2A - Qa-1 axis limits the efficacy of immunotherapy, NKG2A blocking antibodies were applied in the TC-1 model together with therapeutic peptide vaccination. Combination treatment with vaccine and NKG2A blockade significantly improved the therapeutic efficacy compared to the vaccine alone, both in terms of survival (P<0.05, median survival 44 vs 31 days) as well as overall response rate, defined as decreased tumor size of more than 30% (93.8% vs 43.8%, respectively). Similar results were obtained in Qa-1-deficient mice, suggesting that Qa-1 on tumor cells is of importance. In conclusion, inhibitory receptor NKG2A is enriched on CD8+ TIL and functions as an immune checkpoint that restrains therapeutic efficacy of a cancer vaccine.

Citation Format: Thorbald van Hall, Nadine van Montfoort, Sytse Piersma, Marjolein Sluijter, Marij J. Welters, Pascale André, Nicolai Wagtmann, Sjoerd H. van der Burg. NKG2A checkpoint receptor expression on tumor-infiltrating CD8+ T cells restrains efficacy of immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2999. doi:10.1158/1538-7445.AM2017-2999
Abstract 3: Targeting epigenetic modifiers in diffuse large B-cell lymphoma
Authors: Goverdhan Aarthi , Lee Heng-Huan , Hung Mien-Chie
Published: July 2017

Diffuse Large B-Cell Lymphoma (DLBCL) is the most common type of Non-Hodgkin lymphoma, accounting for approximately 40% of all cases worldwide. In the last five years, researchers uncovered that DLBCL is characterized by widespread epigenetic deregulation. Lymphoma cells harbor loss-of-function mutations in transcriptional activators (KMT2D, EP300, CREBBP) and gain-of-function mutations in transcriptional repressors (EZH2). In our study, we aim to identify epigenetic vulnerabilities in lymphoma cells that can be targeted to deliver cytotoxic responses. We screened the therapeutic efficacy of a panel of lysine and arginine methyltransferase inhibitors in multiple lymphoma cell lines. Through these screens, we identified the Type I Protein Arginine Methyltransferase (PRMT) family as an attractive therapeutic target that induced cytotoxicity. Mechanistic dissection revealed that Type I PRMT inhibition caused apoptosis through deregulation of transcription factors and pro-survival genes. In addition, we uncovered novel crosstalk between PRMTs and other epigenetic modifiers that influenced cell fate in lymphoma. Our study demonstrates a critical role for Type I PRMTs in DLBCL, and adds a lucrative target to the growing list of promising epigenetics-based therapies.

Citation Format: Aarthi Goverdhan, Heng-Huan Lee, Mien-Chie Hung. Targeting epigenetic modifiers in diffuse large B-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3. doi:10.1158/1538-7445.AM2017-3
Abstract 300: Taeumjowi-tang (TJ001) induces G2/M cell cycle arrest but not apoptosis in p53-mutant prostate cancer via up-regulation of p21WAF/CIP1
Authors: Kang Soo-Yeon , Kim Hyo In , Hong Se Hyang , Ku Jin Mo , Lee Kangwook , Kim Myeong-Sun , Choi Yu-jeong , Cheon Chunhoo , Ko Youme , Huang Ching Wen , Sasaki Yui , Kang Sohyeon , Seo Hye-Sook , Kim Tai Young , Kim Ji Hye , Shin Yong Cheol , Ko Seong-Gyu
Published: July 2017

Taeumjowi-tang (TJ001) is a traditional Korean medicine that usually prescribed for Tae-um person to regulate stomach-related symptoms including headache, indigestion, and jaundice. Other studies on anti-obesity effect of TJ001 have also been researched, but have never been reported as a cure for cancer. In the present study, we investigated the molecular mechanism that TJ001 induces G2/M cell cycle arrest in DU145 (p53-mutant) prostate cancer cells. The missense mutation in human p53 gene (TP53) confers oncological effect to tumor suppressor p53-mutant protein. In prostate cancer, this gain-of-function of p53-mutant is associated with androgen-independence, increased angiogenesis, and metastasis. Our in vitro studies showed that a water extract of TJ001 induced G2/M cell cycle arrest via p53-mutant status and p21WAF/CIP1 up-regulation. Conventinally, p21WAF/CIP1 is induced by mediating p53 regulation, but, in experiments, handling the p53-dependent and -independent pathway. Although serine15-phosphorylated p53 and p53 proteins remained unchanged, p21WAF/CIP1 expression is induced and cyclin B1/Cdc2 complex is inactivated by a decrease of cyclin B1. In addition, in p53-independent pathway, the level of Cdc25C expression decreased and Serine-216 phosphorylated Cdc25C increased. Generally, concomitant with G2/M cell cycle arrest come the apoptosis cell death, but in the study, prolonged G2/M cell cycle arrest developed not apoptosis but cell senescence. Therefore, our data suggest that TJ001 is helpful for p53-mutant prostate cancer treatment.

Citation Format: Soo-Yeon Kang, Hyo In Kim, Se Hyang Hong, Jin Mo Ku, Kangwook Lee, Myeong-Sun Kim, Yu-jeong Choi, Chunhoo Cheon, Youme Ko, Ching Wen Huang, Yui Sasaki, Sohyeon Kang, Hye-Sook Seo, Tai Young Kim, Ji Hye Kim, Yong Cheol Shin, Seong-Gyu Ko. Taeumjowi-tang (TJ001) induces G2/M cell cycle arrest but not apoptosis in p53-mutant prostate cancer via up-regulation of p21WAF/CIP1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 300. doi:10.1158/1538-7445.AM2017-300
Abstract 3002: Therapeutic targeting of PGBD5-induced DNA repair dependence in pediatric solid tumors
Authors: Henssen Anton , Reed Casie , Jiang Eileen , Wai Wong , Stanchina Elisa de , Kuwahara Yasumichi , Hosoi Hajime , Schulte Johannes H. , Ganem Neil , Petrini John , Kentsis Alex
Published: July 2017

Despite intense efforts, the cure rates of childhood solid tumors are not satisfactory. Resistance to intensive chemotherapy is common, and targets for molecular therapies are largely undefined, particularly for tumors caused by aberrant developmental and epigenetic factors. We have now found that the majority of childhood solid tumors, rhabdoid tumors, neuroblastoma, medulloblastoma and Ewing sarcoma, express an active DNA transposase PGBD5. Using functional genetic approaches, we observed that mouse and human cells deficient in non-homologous end joining (NHEJ) DNA repair cannot tolerate the expression of PGBD5. In a chemical screen of DNA repair inhibitors, we identified the ATR/ATM inhibitor AZD6738 as a specific sensitizer of PGBD5-dependent DNA damage and apoptosis. Ectopic expression of PGBD5 was sufficient to induce hypersensitivity to AZD6738, and endogenous PGBD5 was necessary for its anti-tumor effects. We found that PGBD5-expressing tumor cells accumulate unrepaired DNA damage in response to AZD6738 treatment, and undergo apoptosis in both dividing and G1 phase cells in the absence of measureable DNA replication stress. Accordingly, AZD6738 exhibits nanomolar potency against the majority of neuroblastoma, medulloblastoma, Ewing sarcoma and rhabdoid tumor cells tested, while sparing non-transformed human and mouse embryonic fibroblasts in vitro. Finally, AZD6738 exhibits excellent single-agent activity against high-risk neuroblastoma and medulloblastoma xenografts, with induction of apoptosis and tumor regression in vivo. These findings delineate a therapeutically actionable synthetic lethality for the majority of childhood solid tumors.

Citation Format: Anton Henssen, Casie Reed, Eileen Jiang, Wong Wai, Elisa de Stanchina, Yasumichi Kuwahara, Hajime Hosoi, Johannes H. Schulte, Neil Ganem, John Petrini, Alex Kentsis. Therapeutic targeting of PGBD5-induced DNA repair dependence in pediatric solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3002. doi:10.1158/1538-7445.AM2017-3002