bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1531: Therapeutic strategies for osteosarcoma stem cells by regulating adipocyte differentiation based on actin dynamics
Authors: Nobusue Hiroyuki , Takahashi Nobuhiro , Onishi Nobuyuki , Shimizu Takatsune , Sugihara Eiji , Oki Yoshinao , Akashi Koichi , Kano Koichiro , Saya Hideyuki 
Published: July 2017

Abstract
We generated induced cancer stem cells that initiate osteosarcoma (OS) by overexpression of c-MYC and loss of Ink4a/Arf in bone marrow-derived stromal cells, and found that the loss of adipogenic potential is an essential event for OS tumorigenesis. Therefore, our understanding of regulatory mechanisms of adipocyte differentiateon would greatly contribute to control OS tumorigenesis. Here, we show that regulation of the transcriptional coactivator MKL1 (megakaryoblastic leukemia 1) by actin cytoskeleton dynamics drives adipocyte differentiation mediated by PPARγ. Exposure of preadipocytes to an adipogenic cocktail results in the rapid disruption of actin stress fibres as a consequence of downregulation of RhoA-ROCK signaling, which regulates the formation of actin stress fibers and focal adhesions, and the consequent increase in monomeric G-actin levels. The resulting increase in the amount of G-actin leads to the interaction of G-actin with MKL1, which prevents nuclear translocation of MKL1 and allows expression of PPARγ followed by adipogenic differentiation. We further found that depletion of MKL1 can drive adipocyte differentiation in preadipocytes and even in nonadipogenic fibroblasts in the absence of an adipogenic cocktail, and these data revealed that MKL1 functions as a gatekeeper that controls adipocyte differentiation. In addition, we found that treatment with ROCK inhibitors induced terminal adipocyte differentiateon even in OS stem cells through regulation of MKL1 by actin cytoskeleton dynamics, which resulted in a significant suppression of tumorigenesis. Our findings provide new insight into the regulatory mechanism of adipogenesis, and trans-differentiation approach by controlling actin cytoskeleton dynamics may provide a novel therapeutic strategy for targeting cancer stem cells.
Citation Format: Hiroyuki Nobusue, Nobuhiro Takahashi, Nobuyuki Onishi, Takatsune Shimizu, Eiji Sugihara, Yoshinao Oki, Koichi Akashi, Koichiro Kano, Hideyuki Saya. Therapeutic strategies for osteosarcoma stem cells by regulating adipocyte differentiation based on actin dynamics [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 1531. doi:10.1158/1538-7445.AM2017-1531
Abstract 1538: A mouse model that mimics human MEN1 tumor is effective in preclinical neuroendocrine tumor therapeutics
Authors: Wong Chung , Clausen Richard , Tang Laura , Davidson Christian , Vosburgh Evan , Levine Arnold , Xu Eugenia 
Published: July 2017

Abstract
Conditional knockout of Men1 in β cells leads to development of pituitary adenomas and pancreatic neuroendocrine tumors (PanNETs) by the age of eight to twelve months. This suggests that other events, like loss of additional mutations, may be required for development of tumors in the absence of MEN1. Since it was reported that mutations in genes of PI3K/mTOR pathway are found in human neuroendocrine tumors, we hypothesized that double deletion of PTEN and MEN1 may accelerate neuroendocrine tumorigenesis. Mice with double deletion of PTEN and MEN1 in β cells were produced by crosses among mice with Cre gene under the control of Rat Insulin promoter (Rip-Cre), floxed allele Men1 (Men1fl/fl), and Pten (Ptenfl/fl). Then mice with the genotype of Men1fl/fl Ptenfl/fl Rip-Cre were monitored for development of tumors. Consistent with our hypothesis, mice with conditional deletion of PTEN and MEN1 leads to fully developed PanNETs and pituitary adenomas by three to four months old, much earlier than that with Men1 deletion alone. These tumors resemble human MEN1 tumors at a histological and molecular level. Activation of phospho-AKT was observed in these tumors and Rapamycin treatments lead to delayed PanNETs and pituitary adenomas for at least two months. This mouse model (Men1fl/fl Ptenfl/fl Rip-Cre) directly supports that PI3K/mTOR pathway plays a critical role in neuroendocrine tumorigenesis, and also provides a platform to study new therapeutic opportunities for PanNETs and neuroendocrine tumors of the pituitary through the targeting of PI3K/mTOR pathway and MEN1 pathway. This model represents an important tool for studying the biology and preclinical therapeutics of human neuroendocrine tumors.
Citation Format: Chung Wong, Richard Clausen, Laura Tang, Christian Davidson, Evan Vosburgh, Arnold Levine, Eugenia Xu. A mouse model that mimics human MEN1 tumor is effective in preclinical neuroendocrine tumor therapeutics [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 1538. doi:10.1158/1538-7445.AM2017-1538
Abstract 1542: Identifying genetic modifiers of PTEN using the Collaborative Cross mouse panel
Authors: Lanier Amanda , Barrington William , Threadgill David 
Published: July 2017

Abstract
Tumor suppressor genes code for proteins that limit cellular proliferation and cancer progression, and are often exploited in cancer therapies. One such tumor suppressor gene, Phosphatase and Tensin homolog deleted from Chromosome Ten (PTEN), mediates cell growth through negative regulation of phosphatidylinositol 3-kinase (PI3K) dependent pathways. PTEN is frequently deleted or mutated in a variety of human cancers. Mice carrying a PTEN transgene (Super-PTEN mice) were found to be resistant to tumor formation, and even small changes in PTEN expression and activity have been shown to influence cancer susceptibility and progression. We hypothesized that PTEN activity can be altered by modifier genes. To determine whether PTEN modifiers are influencing its activity, we are using the Collaborative Cross (CC), a panel of inbred mouse strains that has a similar amount of genetic variation as human populations. In CC-Super-PTEN crosses, we are utilizing an easily measured phenotype of Super-PTEN mice, reduced body weight, to identify CC strains with altered PTEN function. On average, weanlings carrying the PTEN transgene weigh 16% less than their wild type littermates, but this weight difference varies significantly across strains, from no weight reduction to as much as a 29% difference. This distribution of phenotypes has allowed us to use quantitative trait locus (QTL) mapping to identify potential modifiers of PTEN. Through association mapping, we have determined that the loci with the highest LOD scores reside on chromosomes 2, 12, 16, and X, and we are now reviewing genes within those loci to identify candidate modifiers of PTEN. Additionally, we are using several cancer models to determine the effects of said candidate genes and confirm that an altered PTEN weight phenotype correlates with changes in cancer susceptibility and progression. Ultimately, this research will demonstrate the use of the CC mouse panel to identify novel genetic modifiers and improve our understanding of PTEN regulation.
Citation Format: Amanda Lanier, William Barrington, David Threadgill. Identifying genetic modifiers of PTEN using the Collaborative Cross mouse panel [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 1542. doi:10.1158/1538-7445.AM2017-1542
Abstract 1544: MTAP insufficiency promotes metastasis in lung cancer via diminishing protein dimethylation
Authors: Chang Wen-Hsin , Ho Bing-Ching , Su Kang-Yi , Chen Jian-Wei , Wu Reen , Yang Pan-Chyr , Yu Sung-Liang 
Published: July 2017

Abstract
Genome instability, metabolic switch, and activating metastasis are three of the cancer hallmarks, which always collectively contribute to cancer malignancy. We identified methylthioadenosine phosphorylase (MTAP) as a metastasis suppressor in a series isogenic lung cell lines with different invasion ability by array CGH. Using siRNA silencing and ectopic expression of MTAP, we found that MTAP not only inhibited invasion and colony forming in vitro, but also reduced metastasis and tumorigenesis in vivo. Clinically, patients with low MTAP expression associated with poor overall survival and progression-free survival. Furthermore, the metabolite analysis of clinical specimens showed that low MTAP expression leads to MTA substrate accumulation and product decrease. MTA accumulation in MTAP knockout cells reduced the level of symmetric arginine dimethylation of proteins. By using LC/MS, we identified a novel methyl-protein, whose level is elevated in MTAP knockout cells with the depletion of symmetric arginine dimethylation. Functionally, the unmethylated protein would be protected from proteolysis via caspase 3 cleavage. Moreover, the unmethylated mutant protein promoted migration and invasion in vitro strongly than the wild-type one did. In conclusion, we identify a novel marker in low MTAP expression or MTAP knockout cells, providing a potential therapeutic candidate in lung adenocarcinoma.
Citation Format: Wen-Hsin Chang, Bing-Ching Ho, Kang-Yi Su, Jian-Wei Chen, Reen Wu, Pan-Chyr Yang, Sung-Liang Yu. MTAP insufficiency promotes metastasis in lung cancer via diminishing protein dimethylation [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 1544. doi:10.1158/1538-7445.AM2017-1544
Abstract 1552: Integrative bioinformatics analyses of ChIP seq and RNA seq data reveals a complex regulatory landscape of NRF1 network involved in the pathogenesis of breast cancer
Authors: Ramos Jairo , Roy Deodutta 
Published: July 2017

Abstract
The expression of redox sensitive transcription factor -nuclear respiratory factor 1 (NRF1) expression significantly correlates with histological grades and prognosis of breast cancer. However, the molecular mechanism by which NRF1 may contribute in the development of breast cancer is not clear. In this study we examined whether NRF1 is a molecular risk factor of breast cancer. We also identified regulatory landscape of NRF1 network involved in the pathogenesis of breast cancer. Steps followed for the investigation included the selection of mRNA microarray dataset from TCGA and Metabric, selection and analysis of ChIP-Seq datasets from different breast cancer cell lines to identify NRF1 target genes possibly involved in breast cancer through Molecular Pathway, Gene Ontology and statistical analysis. Analysis of mRNA expression in breast cancer patients showed that NRF1 was significantly overexpressed in breast cancer tissues compared to normal tissues. ChIP-Seq analysis of two different breast cancer cell line - MCF7 and T7D showed that there are more than 8,000 genes, which contain NRF1 binding DNA motif(s). The NRF1 binding to ChIP DNA sequences of target gene is cell context dependent. High percentage of known breast cancer (~50%) susceptibility genes are transcriptional targets of NRF1. Network analysis revealed that NRF1 regulates genes, which are key regulators of epithelial-mesenchymal transition (EMT), stemness, cell apoptosis, cell cycle regulation, chromosomal integrity, and DNA damage and repair. Furthermore, we observed that NRF1 regulates target genes of both breast cancer and cancer KEGG pathways. Many of the MicroRNAs involved in cancer and genes of signaling pathways involved in cancer initiation and progression such as MAPK, PI3K/AKT and Notch signaling are also transcriptional targets of NRF1. In summary, this study reveals a complex regulatory landscape of NRF1 network involved in the pathogenesis of breast cancer. Dysregulation of NRF1 signaling pathways may contribute in the development of breast cancer. Clinical confirmation of our study will have significant impact on our understanding of the role of NRF1 as a valuable biomarker for breast cancer diagnosis and prognosis and will provide strong rationale for the future studies to further develop NRF1 for breast cancer therapeutic target. This work was in part supported by a VA MERIT Review (VA BX001463) grant to DR.
Citation Format: Jairo Ramos, Deodutta Roy. Integrative bioinformatics analyses of ChIP seq and RNA seq data reveals a complex regulatory landscape of NRF1 network involved in the pathogenesis of 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 1552. doi:10.1158/1538-7445.AM2017-1552
Abstract 1564: A computational framework for removing mouse contamination in tumors sequenced from patient-derived xenografts
Authors: Amin-Mansour Ali , Jané-Valbuena Judit , Mu Xinmeng Jasmine , Garraway Levi 
Published: July 2017

Abstract
Introduction: Using patient derived xenograft (PDX) models has become an effective way for investigating response to standard or new therapeutics in cancer. Human cancer cells injected in mice are allowed to establish tumors and subjected to desired treatments. The PDX tumors are later harvested and characterized, often by massive parallel sequencing. However, a major challenge with analyzing these data is the presence of stromal mouse genomic material, frequently resulting in artifacts in downstream variant detection. We present a computational method to eliminate mouse contamination in PDX.
Method: We used the Burrows-Wheeler Aligner to map reads obtained from sequencing the PDX samples to a combined human and mouse reference genome . We remove reads that are mapped to the mouse reference. The remaining reads are then processed through standard mutation calling pipelines for somatic mutation detection. To test the efficacy of our method, we created in silico mixtures of human and mouse whole-exome sequencing reads from a melanoma patient’s tumor and an immortalized mouse cell line captured with human exome baits. We then carried out a sensitivity analysis to examine how changing the mean target coverage of sequencing, or mouse contamination levels affects our results. For each of the computational experiments, we evaluated somatic mutations detected from the synthetic samples in comparison to the original human sample.
Results: We calculated the sensitivity and specificity of detecting somatic mutations to determine our algorithm’s performance. In all instances, we found greater than 99% for both sensitivity and specificity.
Conclusions: Our results demonstrate that our method works accurately towards removing mouse reads in PDX samples. This task could also be applied to separating sequence reads from other species.
Citation Format: Ali Amin-Mansour, Judit Jané-Valbuena, Xinmeng Jasmine Mu, Levi Garraway. A computational framework for removing mouse contamination in tumors sequenced from patient-derived xenografts [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 1564. doi:10.1158/1538-7445.AM2017-1564
Abstract 1566: Differential expression of Epstein Barr virus miRNAs in triple-negative breast cancer
Authors: Blanchard Alexander , Walls Tiffany , Vidal Ramon , Bonn Stefan , Harrison Scott , Muganda Perpetua 
Published: July 2017

Abstract
Triple-negative breast cancers (TNBC) accounts for up to 20% of breast cancer cases. These tumors are negative for estrogen, progesterone, and HER2 receptors, which are markers used for diagnosis and treatment of other types of breast cancer. Clinically, TNBCs are notoriously aggressive, respond poorly to targeted therapies, have high rates of relapse, as well as poor prognosis. The molecular basis of TNBC oncogenesis is currently unknown, but it is possible that viral factors, such as Epstein-Barr Virus (EBV) miRNAs, play a role. EBV miRNAs have been implicated in the oncogenesis of several forms of cancer, including Burkitt’s lymphoma and nasopharyngeal carcinoma. The objective of this study, therefore, was to determine the differential expression of EBV miRNAs in TNBC tumors as compared to normal breast tissue. We conducted a comprehensive profiling of viral miRNAs in 48 TNBC tumors as compared to 15 control normal breast tissues, utilizing deep sequencing analysis software and publically available deep sequencing data. Four EBV miRNAs (BART18-3p, BART 8-5p, BART15, BART22) were significantly expressed in 11-17% of the TNBC tumors, and not in control normal breast tissue. Four novel putative EBV miRNAs were found to be differentially expressed in TNBC tumors as compared to control normal cells. Two of the novel putative EBV miRNAs were differentially expressed above 125 reads per million (RPM) in 20% and 27% of the TNBC tumors as compared to 0% and 6.6% of normal breast tissues, respectively. One novel putative EBV miRNA was expressed above 125 RPM in 83% of TNBC tumors as compared to 13% of normal breast tissue. One novel putative EBV miRNA was expressed above 125 RPM in 66% of the normal breast tissue as compared to 2% of the TNBCs. These putative EBV miRNAs localize within genomic regions of EBV, including the LMP-2 region. Ongoing work has so far computationally validated one of these miRNAs as a novel EBV miRNA; in vitro validation studies are in progress. This is the first report on the differential expression of EBV miRNAs in TNBC tumors. Since TNBC tumors are extremely heterogeneous, it is intriguing that 20% of TNBC tumors specifically express the same EBV miRNA. Our findings suggest that these differentially expressed EBV miRNAs may potentially play a role in the pathogenesis of TNBC.
Citation Format: Alexander Blanchard, Tiffany Walls, Ramon Vidal, Stefan Bonn, Scott Harrison, Perpetua Muganda. Differential expression of Epstein Barr virus miRNAs 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 1566. doi:10.1158/1538-7445.AM2017-1566
Abstract 157: Targeting distinct nodes of the PI3K/AKT/mTOR cascade in prostate cancer cells: impact on cell proliferation, apoptosis and pathway signaling
Authors: Marques Rute B. , Aghai Ashraf , Stam Wendy , Weerden Wytske M. van 
Published: July 2017

Abstract
Inactivation of the PTEN gene is a common event in PCa, leading to activation of the PI3K/AKT/mTOR pathway and promoting PCa progression. Inhibitors targeting this pathway are currently being developed as anticancer agents. While recent clinical trials with mTORC1 inhibitors have shown limited single-agent efficacy in castration-resistant prostate cancer (CRPC), it is still not known whether targeting alternative nodes of the PI3K/AKT/mTOR cascade may improve response. The current study aimed to characterize the response of PCa cell lines to multiple inhibitors targeting the PI3K, AKT and mTOR nodes of the cascade and identify possible mechanisms of resistance.
The impact of the different PI3K/AKT/mTOR inhibitors on cell proliferation and apoptosis was measured by WST-1 and ApoTox-Glo assays, respectively, in a broad panel of established PCa cell lines and primary cell cultures generated from patient-derived xenografts. PTEN-negative PCa cell lines showed strong response to PI3Kβ/δ, AKT and mTOR inhibition, whereas PTEN-positive cells were resistant to PI3Kβ/δ and showed variable sensitivity to mTOR inhibitors. MTORC1 inhibitor showed low IC50 but reached plateau at about 70-80% growth inhibition. In contrast, mTORC1/2 inhibitor could reach complete growth inhibition at ~1μM concentration, in sensitive cell lines. Furthermore, treatment with PI3K or AKT inhibitor in combination with androgen depletion induced apoptosis in various PTEN-negative models, which is consistent with previously reported synergistic effect of PI3K/AKT and androgen receptor co-targeting. The effect of the inhibitors on phosphorylation of PI3K downstream targets (AKT, PRAS40, GSK3, S6K1 and 4EBP1) was analyzed by phospho-specific western blotting. Perturbation of different nodes of the PI3K/AKT/mTOR cascade resulted in differential phosphorylation of downstream targets, but there was no evident correlation with in vitro growth inhibition.
In conclusion, the current study validates PI3Kβ and AKT as alternative targets in PTEN-negative PCa, whereas PTEN-positive models showed preferential yet variable responses towards mTOR inhibitors.
Citation Format: Rute B. Marques, Ashraf Aghai, Wendy Stam, Wytske M. van Weerden. Targeting distinct nodes of the PI3K/AKT/mTOR cascade in prostate cancer cells: impact on cell proliferation, apoptosis and pathway signaling [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 157. doi:10.1158/1538-7445.AM2017-157
Abstract 1583: Inhibition of proline isomerase Pin1 interrupts the function of the androgen receptor N-terminal domain and suppresses androgen-independent growth of prostate cancer cells
Authors: Leung Jacky K. , Imamura Yusuke , Kato Minoru , Mawji Nasrin R. , Sadar Marianne D. 
Published: July 2017

Abstract
Patients with advanced prostate cancer continue to develop lethal castration-resistant prostate cancer (CRPC) despite hormone therapy and maintaining castrate levels of serum androgen. Most CRPC appears to be dependent on the androgen receptor (AR), but instead of the C-terminal ligand-binding domain, it is the N-terminal domain (NTD) harboring a powerful transactivation domain that drives AR transcriptional activity. This was supported by the discovery of AR splice variants (ARv567es and V7) which are constitutively active, do not encode a functional ligand-binding domain, and correlate with poor patient outcome. The AR NTD is intrinsically disordered, but it contains several putative binding sites for Pin1, a proline isomerase specific for phosphorylated-Ser/Thr-Pro motifs. Since the innate ability of the AR NTD to adopt multiple transient structures is important for transactivation of AR, we aimed to determine whether Pin1 regulates motifs within the AR NTD.
We tested several known inhibitors of Pin1 in cell-based assays that measure proliferation or transcription mediated by AR. Our results demonstrated that inhibition of Pin1 interrupted the function of the AR NTD. The Pin1 inhibitor juglone effectively and specifically blocked transcription mediated by AR induced by androgen, as well as transactivation of the AR NTD in the presence of IL-6. We found that Pin1 predominantly interacted with a specific region of the AR NTD containing two Pin1 binding sites, and by inhibiting Pin1 the interactions between endogenous AR and STAT3 became attenuated. Furthermore, Pin1 inhibitors were more effective than second-generation anti-androgens in blocking androgen-independent proliferation of LNCaP95 cells driven by AR variants.
Here we describe that Pin1 is a critical factor for transcription mediated by AR, regardless of ligand, by regulating the AR NTD. Understanding the molecular mechanisms that may promote AR signaling in the absence of androgen will aid the development of more effective therapies for CRPC.
Citation Format: Jacky K. Leung, Yusuke Imamura, Minoru Kato, Nasrin R. Mawji, Marianne D. Sadar. Inhibition of proline isomerase Pin1 interrupts the function of the androgen receptor N-terminal domain and suppresses androgen-independent growth of prostate cancer 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 1583. doi:10.1158/1538-7445.AM2017-1583