bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 5095: Concurrent Dnmt3a haploinsufficiency partially abrogates competitive disadvantage in Smc3 haploinsufficient myeloid cells
Authors: Wang Tianjiao , Welch John S. 
Published: August 2018

Abstract
SMC3 encodes a subunit of cohesin associated with recurrent heterozygous mutations in acute myeloid leukemia (AML) and other myeloid malignancies. About one-third of these mutations are predicted loss-of-function (nonsense and splice-site mutations) and the rest are missense with unclear function. To understand whether these missense mutations might have dominant-negative effects or phenocopy loss-of-function effects, we compared the consequences of Smc3 deficient and haploinsufficient mouse models. We found that both embryonic and somatic deletion of homozygous Smc3 alleles led to complete hematopoietic failure. Furthermore, in competitive transplantation, following engraftment and subsequent tamoxifen treatment, the Smc3fl/fl/ERT2-Cre+/- BM cells were rapidly outcompeted, with earliest cell loss in the Gr1+ myeloid compartment. Hence, Smc3 is indispensable for hematopoiesis and AML-associated SMC3 missense mutations are unlikely to have dominant-negative effects. We examined the consequences of somatic Smc3 haploinsufficiency using Smc3fl/+/ERT2-Cre+/-. We found that Smc3 haploinsufficiency did not lead to increased number of initial methylcellulose colonies, nor did these cells replate beyond two weeks. In competitive transplantations, we again observed a significant competitive disadvantage in the Smc3fl/+/ERT2-Cre+/- BM cells, most pronounced in the Gr1+ myeloid cells. Competitive disadvantage is counter-intuitive for a leukemia-associated mutation. SMC3 mutations frequently co-occur with DNMT3A mutations. We, therefore, asked whether Smc3 haploinsufficiency might lead to a competitive advantage if it occurred in the background of Dnmt3a haploinsufficiency. With the addition of Dnmt3a haploinsufficiency, the severe myeloid competitive disadvantage was partially ameliorated, but the significant competitive disadvantage in other lineages remained intact. In summary, our data demonstrate that homozygous Smc3 deletion was incompatible with embryonic or adult hematopoiesis, with the greatest defects noted within myeloid compartment, indicating that AML-associated SMC3 mutations are unlikely to have dominant-negative effects. Smc3 haploinsufficiency resulted in a myeloid competitive disadvantage, which was partially abrogated in the presence of concurrent Dnmt3a haploinsufficiency, suggesting lineage-specific interactions between the mutations.
Citation Format: Tianjiao Wang, John S. Welch. Concurrent Dnmt3a haploinsufficiency partially abrogates competitive disadvantage in Smc3 haploinsufficient myeloid cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5095.
Abstract 5097: Knock-in of a human tumor suppressor (25-kilobase pairs) by traditional and CRISPR/Cas9-stimulated homologous recombination
Authors: Leidy-Davis Tiffany , Cheng Kai , Goodwin Leslie , Morgan Judith , Juan Wen Chun , Roca Xavier , Ong Sin-Tiong , Bergstrom David E. 
Published: August 2018

Abstract
Here we describe an expansion of the DNA size limitations associated with CRISPR knock-in technology, more specifically, the physical extent to which mouse genomic DNA can be replaced with donor (in this case, human) DNA at an orthologous locus. Driving our efforts was the desire to create a whole animal model inserting a 25-kbp segment of a human tumor-suppressor gene in place of 17 kbp of its corresponding mouse orthologue. Included within the human fragment is a conditionally removable (by Cre-loxP) segment of the gene's second intron, a cryptic exon immediately 3' of this, and a native exon some 20 kbp downstream. Using two methods, we first carried out the replacement by employing a combination of bacterial artificial chromosome recombineering, classic ES cell targeting, dual selection, and recombinase-driven cassette removal (traditional approach). Using a unique second method, we employed the same vector (devoid of its selectable marker cassettes), microinjecting it along with CRISPR RNA guides and Cas9 into mouse zygotes (CRISPR approach). In both instances, we were able to achieve humanization of the tumor suppressor to the extent designed, remove all selection cassettes, and demonstrate the functionality of the conditionally removable, loxP-flanked, intronic segment.
Citation Format: Tiffany Leidy-Davis, Kai Cheng, Leslie Goodwin, Judith Morgan, Wen Chun Juan, Xavier Roca, Sin-Tiong Ong, David E. Bergstrom. Knock-in of a human tumor suppressor (25-kilobase pairs) by traditional and CRISPR/Cas9-stimulated homologous recombination [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5097.
Abstract 5099: Evaluating Ago2 as an oncogene in Kras-dependent lung carcinoma
Authors: Goodrum Andrew E. , Wang Lisha , Xu Alice , Juckette Kristin M. , Chinnaiyan Arul M. , Tien Jean C. 
Published: August 2018

Abstract
Background: Lung cancer is the deadliest malignancy in the United States. Non-small cell lung cancer (NSCLC) accounts for 85% of cases, and is frequently driven by activating mutations in the gene encoding the KRAS GTPase (e.g. KRASG12D). Our previous work demonstrated that Argonaute 2 (AGO2)—a component of the RNA induced silencing complex (RISC)—physically interacts with KRAS and stabilizes it at the protein level. In NSCLC cell lines, AGO2 knockdown reduces KRAS protein level and attenuates cell proliferation. We hypothesized that AGO2 acts as an oncogene in KRASG12D-dependent NSCLC in vivo.
Methods: To test the hypothesis, we generated a NSCLC model by intercrossing mice harboring a stop-floxed KRASG12D allele with animals containing a tamoxifen-responsive Cre recombinase gene driven by the (clara cell-specific) CCSP promoter. These animals, which frequently die within 10 weeks of tamoxifen treatment, display pulmonary lesions including hyperplasia, adenoma and frank adenocarcinoma. We evaluated whether concomitant ablation of one or both copies of (floxed) AGO2 influenced the NSCLC phenotype. After tamoxifen administration, we monitored mice daily and harvested tissues when mice were clinically moribund or reached 16 weeks of post-treatment. We harvested lungs for gross/ pathological examination and gene/ protein expression analysis.
Results: While pathologically discernable adenocarcinoma was detectable in AGO2+/+ and AGO2f/+ animals, AGO2f/f mice were free of these lesions. Despite this, deletion of AGO2 had no impact on frequency or extent of hyperplastic or adenomatous lesions. Immunohistochemistry demonstrated absence of AGO2 in tumor tissue of AGO2f/f mice.
Conclusion: AGO2 promotes progression but not initiation of cancerous lesions in a mouse model of KRASG12D-dependent NSCLC.
Citation Format: Andrew E. Goodrum, Lisha Wang, Alice Xu, Kristin M. Juckette, Arul M. Chinnaiyan, Jean C. Tien. Evaluating Ago2 as an oncogene in Kras-dependent lung carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5099.
Abstract 510: MicroRNA-8073 as a tumor suppressor and a potential diagnostic and therapeutic target
Authors: Mizoguchi Atsuko , Takayama Aiko , Arai Taiga , Kida Yuho , Kawauchi Junpei , Sudo Hiroko 
Published: August 2018

Abstract
MicroRNAs (miRNAs) generated inside cells are also present in peripheral blood. MiR-8073 has been studied in various disease model, but its molecular function had been unknown. In this study, we demonstrated that miR-8073 regulates target genes that participate in cell survival and works as a tumor suppressor controlling only cancer cells.
First, we observed that miR-8073 expression was evidently decreased in multiple types of cancer cells compared to normal cells, but was increased in cancer exosome secreted into cultured supernatant. We then transfected synthetic miR-8073 mimic into various cancer cell lines and found dramatic reduction in cell proliferation, which was not detected in normal cells. Additionally, in tumor xenograft mice model, three-time subcutaneous injections of miR-8073 mimic at 2nM suppressed 57% growth of colorectal tumor weight.
Through mRNA expression analysis and in silico sequence analysis, we further identified five potential miR-8073 targets that plays critical roles in regulation of cell proliferation, cycle and apoptosis, and demonstrated that miR-8073 indeed bound with the 3'-UTR of these target mRNAs and reduced both mRNA and protein expression.
These results suggest that miR-8073 is a potential tumor suppressor, possibly discarded from cancer cells for their survival out to extracellular space, and circulates in bloodstream in the form of exosome. Our findings promise miR-8073 as a novel cancer diagnostic and therapeutic target.
Citation Format: Atsuko Mizoguchi, Aiko Takayama, Taiga Arai, Yuho Kida, Junpei Kawauchi, Hiroko Sudo. MicroRNA-8073 as a tumor suppressor and a potential diagnostic and therapeutic target [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 510.
Abstract 5106: CRISPR/Cas9-based development of RNAi rat models for drug discovery
Authors: Premsrirut Prem K. , Wang Chia-Lin , Yang Yu-Ting , Dow Lukas E. , Zuber Johannes , Lowe Scott W. 
Published: August 2018

Abstract
The cost of drug development has skyrocketed to an estimated $2.6B for every FDA approved drug primarily due to failures from lack of efficacy or safety. This suggests that our current preclinical validation process has been insufficient in predicting therapeutic potential and toxicity in humans. While genetically engineered animal models have been highlighted as the gold standard for dissecting cancer mechanisms and evaluating novel drug targets in vivo, the cost and long lead time to develop them previously prevented their routine use in the oncology drug discovery process. Now, with the advent of CRISPR/Cas9 technology, the speed and precision in which genetically engineered mouse models can be created is unprecedented. When combined with inducible RNA inteference technology, we we can not only generate cancer de novo in a few weeks time, but also mimic drug therapy via RNAi in the same mice, giving us advanced capabilities to perform preclinical studies in vivo. Despite the utility of mouse models, the rat has historically been the major model species in many biomedical fields, notably toxicology and carcinogenicity testing; and for many scientists, the rat still remains the preferred rodent due to their larger size for surgical manipulation, repeat blood sampling, and their cognitive and physiological characteristics that more closely resemble humans than their mouse counterparts. Here, we take advantage of our two-step engineering approach and exploit the efficiency of CRISPR-based targeting to develop RNAi rat models that enable inducible and reversible gene silencing to simulate therapeutic regimes. We demonstrate that our approach allows us to rapidly generate RNAi rat models and mimic the function of the targeted small molecule inhibitors, such as BET inhibitors targeting Brd4. We compare our results to our Brd4 RNAi mice and demonstrate organism variances that provide valuable insight to cross-species differences. These results demonstrate that our high-throughput system currently used to generate RNAi mice is also applicable to the rat system and, by extension, other mammalian models. Inducible RNAi rat models will undoubtedly be powerful tools that can be used to model human cancers, to mimic the action of putative drugs, and to assess the potential of therapeutic targeting strategies in vivo prior to the costly drug development, ultimately guiding the development of safer and more effective drugs.
Citation Format: Prem K. Premsrirut, Chia-Lin Wang, Yu-Ting Yang, Lukas E. Dow, Johannes Zuber, Scott W. Lowe. CRISPR/Cas9-based development of RNAi rat models for drug discovery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5106.
Abstract 5109: Somatic CRISPR/Cas9-mediated gene editing enables versatile brain tumor modeling
Authors: Zuckermann Marc , Ismer Britta , Hovestadt Volker , Knobbe-Thomsen Christiane B. , Zapatka Marc , Northcott Paul A. , Roussel Martine F. , Reifenberger Guido , Lichter Peter , Pfister Stefan M. , Kawauchi Daisuke , Gronych Jan , Jones David T. 
Published: August 2018

Abstract
Despite substantial advances in the molecular classification of pediatric brain tumors over the last decade, many tumors are still incurable, have a poor prognosis or therapy-related detrimental long term effects. To develop innovative and modern therapy approaches, sophisticated mouse models, faithfully reflecting the human disease are urgently needed.
However, the development of transgenic mouse lines is a time consuming process that is confronted with an increasing number of candidate genes resulting from next generation sequencing of tumor specimens. To cope with this discrepancy, more adaptable animal models are needed. Using somatic gene transfer to manipulate cells in situ holds great advantages in terms of speed and flexibility.
We therefore established a system in which we are using the CRISPR/Cas9 system for somatic disruption of candidate tumor suppressor genes (TSGs) in combination with transposon-mediated overexpression of candidate oncogenes to induce murine brain tumors. By deleting Ptch1 in murine cerebella, we induced Sonic Hedgehog (SHH) subgroup medulloblastoma with high penetrance and short latency. We characterized the induced mutations in depth and did not detect recurrent off-targets using unsupervised whole genome sequencing. We further demonstrated that this method is suited to induce other brain tumor entities by targeting multiple TSGs at the same time or by combining TSG targeting with overexpression of certain oncogenes. To date we established five novel mouse models using this system. Two of these resulted from simultaneous deletion of Nf1, Pten and Trp53 or from combining overexpression of a MET fusion with a loss of Trp53, respectively. Both of these combinations led to efficient glioblastoma induction in the murine forebrain. Our results demonstrate a fast and flexible system for validating novel candidate genes and for generating faithful animal models of human cancer.
Citation Format: Marc Zuckermann, Britta Ismer, Volker Hovestadt, Christiane B. Knobbe-Thomsen, Marc Zapatka, Paul A. Northcott, Martine F. Roussel, Guido Reifenberger, Peter Lichter, Stefan M. Pfister, Daisuke Kawauchi, Jan Gronych, David T. Jones. Somatic CRISPR/Cas9-mediated gene editing enables versatile brain tumor modeling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5109.
Abstract 513: Antitumor miR-451a regulatory network is associated with poor prognosis of renal cell carcinoma
Authors: Yamada Yasutaka , Sugawara Sho , Arai Takayuki , Okato Atsushi , Kojima Satoko , Naya Yukio , Ichikawa Tomohiko , Seki Naohiko 
Published: August 2018

Abstract
Renal cell carcinoma (RCC) is the most common neoplasm of the kidney, and approximately 70-80% of RCCs are classified as clear cell-type (ccRCC). Approximately 350,000 new cases are diagnosed worldwide, with over 140,000 deaths, every year. Although surgical resection remains the only known curative treatment for localized RCC, a significant percentage of these patients develop relapses or metastatic disease, which are associated with a poor prognosis. Recently developed targeted molecular therapies and immunomodulatory agents are currently being widely used for patients with metastatic or recurrent RCC. However, those advanced treatments are restricted to RCC patients in advanced stages of disease and the 5-year survival rate of the patients is only 5-10%.
MicroRNAs (miRNAs) belong to a class of noncoding RNA molecules that fine-tune the expression of protein coding/noncoding RNAs by repressing translation or cleaving RNA transcripts in a sequence-dependent manner. Aberrantly expressed miRNAs contribute to the initiation, development, and metastasis of several types of cancers, including RCC. Current advanced technologies can be used to identify dysregulated miRNAs in HNSCC clinical specimens. Identification of differentially expressed miRNAs is the first step to elucidating novel miRNA-mediated RNA networks in cancer cell.
Analyses of miRNA expression signature by RNA sequencing revealed that miR-451a is significantly downregulated in RCC tissues. Here, we aimed to identify novel RNA networks for miR-451a regulation in RCC cells. Ectopic expression of miR-451a significantly inhibited cancer cell aggressiveness in RCC cells. The Cancer Genome Atlas (TCGA) showed that low expression of miR-451a was significantly associated with poor survival of patients with RCC (p=0.00305). Genome-wide gene expression analyses were applied to identify miR-451a target genes. A total of 16 genes were identified as putative targets of miR-451a in
RCC cells. Among these targets, high expression of 8 genes (F2, CRELD2, MSC, LENG8, CLEC2D, SPC25, PMM2, BST2 and NSMAF) were significantly associated with poor prognosis of the patients with RCC by large numbers of cohort analyses.
Downregulated miR-451a acted as an antitumor miRNA in RCC cells. Antitumor miR-451a regulatory network was contributed to RCC aggressiveness. The identification of antitumor-mediated oncogenic networks may lead to a better understanding of RCC pathogenesis.
Citation Format: Yasutaka Yamada, Sho Sugawara, Takayuki Arai, Atsushi Okato, Satoko Kojima, Yukio Naya, Tomohiko Ichikawa, Naohiko Seki. Antitumor miR-451a regulatory network is associated with poor prognosis of renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 513.
Abstract 5131: Obese conditions induce changes in stromal fibroblast phenotype
Authors: Harlow Brittany , Davalos Albert , Brenner Andrew , Jolly Christopher , Hursting Stephen , deGraffenried Linda 
Published: August 2018

Abstract
Background: Over 40% of American women present a BMI ≥30, which is particularly alarming since obesity confers a worse prognosis for both pre- and postmenopausal breast cancer patients. Although the molecular mechanisms behind this remain unclear, obese conditions have been shown to upregulate certain components of the cancer-associated fibroblast (CAF) secretome and senescence associated secretory phenotype (SASP), both directly correlated with tumorigenesis. However, studies have yet to determine whether obesity induces a cohesive SASP or CAF-like phenotype from any one cell type of the breast tumor microenvironment. Because fibroblasts represent the most common breast tumor cell type, it is of particular importance to investigate obesity-induced changes in this cellular compartment and their effects on cancer cell behavior. Methods: Direct effects of obesity were examined by exposing IMR-90 and HCA2 human fibroblasts to media supplemented with 2% sera from obese women and measuring changes in gene and protein expression, while indirect effects were evaluated by exposing the fibroblasts to conditioned media (CM) from obesity-stimulated MCF-7 and T47D cells and assessing changes in expression of proinflammatory cytokines. Breast cancer cells were also exposed to CM from obesity-stimulated fibroblasts and measured for changes in proliferation, survival, motility, and invasion. Results and Conclusions: Obese conditions induced proinflammatory changes in fibroblasts both directly and indirectly and stimulated changes in the paracrine signaling between fibroblasts and breast cancer cells. These data contribute to the growing evidence implicating obesity in the promotion of breast cancer progression. Additionally, these findings provide a new line of research to develop potential therapeutic targets to improve outcome.
Citation Format: Brittany Harlow, Albert Davalos, Andrew Brenner, Christopher Jolly, Stephen Hursting, Linda deGraffenried. Obese conditions induce changes in stromal fibroblast phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5131.
Abstract 5132: Lactic acidosis-mediated transcriptomic and metabolomic rewiring in pancreatic cancer cells
Authors: Murthy Divya , Abrego Jaime , King Ryan James , Singh Pankaj Kumar 
Published: August 2018

Abstract
Tumor microenvironment plays a critical role in regulating tumor cell metabolism and progression. The tumor cells are constantly exposed to hypoxia, nutrient starvation, and extracellular acidification that contribute to tumor malignancy. These malignant cells exhibit Warburg effect by maintaining glycolytic phenotype even in the presence of oxygen and excrete lactate and protons via monocarboxylate transporters, and sodium-hydrogen antiporter 1 (NHE1) causing constant acidification of the tumor microenvironment. The tumor cells must thus adapt to acidosis to thrive in such hostile microenvironment. The purpose of the study is to identify the functional response of pancreatic cancer cells to the acidic tumor microenvironment. We performed integrated transcriptomic and metabolomic analyses to identify the existence of low pH-responsive transcriptional and metabolic regulators. Culturing the cells under low pH resulted in a reduction in cell growth and an increase in oxidative stress within the cells. RNA-seq-based transcriptomic analyses revealed that acidosis drives distinct gene expression patterns in PDAC cells with the expression of 499 and 496 genes up- and downregulated, respectively in PDAC cells. GSEA analyses of significantly modulated genes identified pathways including cell cycle, DNA repair, metabolic pathways, ABC transporters, glutathione metabolism, and genes involved in signaling cascades such as the inositide signaling pathway. As the transcriptomic analyses showed an enrichment of metabolic genes, intracellular metabolomic analyses revealed that chronic acidosis leads to a shift in cellular metabolism towards oxidative metabolism. Our studies demonstrate that while chronic acidosis in the tumor microenvironment leads to reduced proliferation and glycolysis in tumor cells, it also results in increased expression of genes involved in cellular migration, signaling pathways and switching to anaplerotic glutamine metabolism in response to an acidic tumor microenvironment. Overall, our studies demonstrate metabolic reprogramming in PDAC cells in response to low pH microenvironments creating a metabolic vulnerability that could be exploited for therapeutic targeting of pancreatic cancer.
Citation Format: Divya Murthy, Jaime Abrego, Ryan James King, Pankaj Kumar Singh. Lactic acidosis-mediated transcriptomic and metabolomic rewiring in pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5132.