bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract A12: The establishment, maintenance, and maladaptive role of epigenetic memory in mediating pancreatic tumorigenesis
Authors: Falvo David J. , Chandwani Rohit 
Published: March 2020

Abstract
Cellular decision-making is highly dependent on cues present in the environment. As such, biologic systems have evolved efficient ways to respond to salient and often transient stimuli by encoding and transducing relevant extracellular information to chromatin. Additionally, accumulating evidence suggests that cells are capable of remembering previously experienced stimuli, allowing them to adjust their behaviors appropriately when confronted in the future with a similar or different stimulus. However, the ability of cells to respond to a transient stimulus and to encode a persistent record of that experience following its resolution has yet to be explored comprehensively in a preneoplastic context. Here we determine the lasting effect in the pancreas of an acinar-to-ductal metaplasia (ADM) event, to elucidate the impact of prior inflammation on tissue function and subsequent tumorigenesis. In a lineage-traced model of acinar cell dedifferentiation, we demonstrate that following ADM, histologically normal acinar cells exhibit broad gains in chromatin accessibility that persist well after exposure to the initial ADM-inducing stimulus. We show that the effect on chromatin is not reflected in the transcriptional state of acinar cells. Moreover, we employ extensive flow-cytometry based analysis of immune cell and niche acinar populations to show there is no long-term cell-extrinsic population, nor a significant expansion of either the Dclk1+ or Nk1r+ acinar populations. Finally, we employ single-cell RNA-seq analyses to define the alterations to epithelial cells and the associated microenvironment long after regeneration following an episode of pancreatitis. These data suggest that inflammation-exposed acinar cells are capable of establishing an altered, persistently accessible chromatin state that lasts long after the initial lineage destabilizing event. Currently we are defining if, following resolution of pancreatitis, activation of mutant Kras will be sufficient to induce premalignant transformation within the acinar compartment that manifests as pancreatic intraepithelial neoplasia (PanIN)—the most common precursor lesion to pancreatic ductal adenocarcinoma (PDAC). Understanding how this postinflammatory chromatin state synergizes with oncogenic stress will further explain why inflammation is a hallmark risk factor for cancer development. Together, our studies will characterize the establishment, maintenance, and maladaptive role of epigenetic memory in the development of pancreatic cancer.
Citation Format: David J. Falvo, Rohit Chandwani. The establishment, maintenance, and maladaptive role of epigenetic memory in mediating pancreatic tumorigenesis [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr A12.
Abstract A15: Elucidating the role of p53 in the cellular origins of pancreatic cancer development
Authors: Flowers Brittany M. , Xu Hang , Hanson Kathryn , Curtis Christina , Vogel Hannes , Wood Laura D. , Attardi Laura D. 
Published: March 2020

Abstract
The tumor suppressor gene TP53 encodes a transcriptional activator critical for suppressing pancreatic ductal adenocarcinoma (PDAC). TP53 mutations, which are most frequently missense mutations in the DNA binding domain, result in both loss of wild-type p53 function and gain of novel, oncogenic functions. Mouse models of PDAC relying on oncogenic Kras and p53 mutation have suggested that either pancreatic acinar or ductal cells, the two major epithelial cell types in the pancreas, may be the cell of origin for PDAC, although there is very limited understanding of the molecular pathways through which p53 mutations contribute to PDAC driven by oncogenic Kras. Moreover, the cellular functions of p53 involved in tumor suppression remain enigmatic. To set up a platform for deconstructing p53 loss-of-function (LOF) and gain-of-function (GOF) pathways, we have generated mouse models to study p53 function in adult mice, mimicking the context of human cancer, using tamoxifen-inducible Cre recombinases to activate Kras (KrasLSL-G12D) in adult mouse pancreatic acinar (Ptf1aCreER) and ductal (Sox9CreER) compartments, in the backdrop of different p53 alleles. To investigate p53 LOF, we generated mouse cohorts with wild-type p53 expression or conditional p53 knockout (p53fl/fl). To examine p53 GOF, we generated mouse cohorts with conditional expression of structural mutant p53R172H (p53LSL-R172H/fl), contact mutant p53R270H (p53LSL-R270H/fl) and conditional p53 knockout (p53null/fl) for comparison in a uniform p53 heterozygous genetic background of stromal tissues. Our tumor studies have demonstrated that oncogenic Kras expression and p53 knockout or mutation in acinar cells of adult mice leads to metastatic PDAC development with complete penetrance. This suggests a novel role for p53 in tumor suppression by blocking cellular reprogramming of acinar cells to ductal-like cells. In contrast, these mutations drive PDAC from ductal cells less efficiently. To understand the origins of human PDAC, we are investigating the molecular pathways altered in mouse acinar and ductal cell-derived tumors. Through comparison with human pancreatic cancer data, our studies will elucidate the cellular origins of different molecular subtypes of human PDAC. Elucidating the mechanisms of PDAC development is critical to improving detection and therapy in PDAC patients.
Citation Format: Brittany M. Flowers, Hang Xu, Kathryn Hanson, Christina Curtis, Hannes Vogel, Laura D. Wood, Laura D. Attardi. Elucidating the role of p53 in the cellular origins of pancreatic cancer development [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr A15.
Abstract A20: Gemcitabine primes the pancreatic tumor microenvironment for second-line immunotherapy
Authors: Principe Daniel R. , Narbutis Matthew , Kumar Sandeep , Park Alex , Viswakarma Navin , Dorman Matthew J. , Kamath Suneel D. , Munshi Hidayatullah G. , Rana Ajay 
Published: March 2020

Abstract
Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related death with a median survival time of 6-12 months. As most patients present with disseminated disease, the majority are offered palliative chemotherapy. As there are no treatment strategies for patients who progress on chemotherapy, we explored the effects of long-term gemcitabine on the tumor microenvironment in order to identify potential therapeutic options in chemorefractory PDAC. Using a combination of mouse models and human-derived PDAC cell lines, we first evaluated chemotherapy-induced alterations in the tumor secretome and immune surface proteins by high-throughput proteomic arrays. In addition to enhancing antigen presentation and immune checkpoint expression, gemcitabine led to large-scale alterations in the tumor secretome, namely by increasing the synthesis of CCL/CXCL chemokines and TGFβ-associated proteins. These secreted factors altered the composition of the tumor stroma, conferring drug resistance to cancer-associated fibroblasts in vitro. We therefore combined gemcitabine with anti-PD-1 in transgenic models of murine PDAC, which failed to alter disease course unless mice also underwent genetic or pharmacologic ablation of TGFβ signaling. In the setting of TGFβ signal deficiency, gemcitabine and anti-PD-1 led to a robust CD8+ T cell-response and decrease in tumor burden. These results suggest that gemcitabine may prime PDAC tumors for immune checkpoint inhibition by enhancing antigen presentation, but requires the inhibition of a TGFβ cytokine barrier. Given the current lack of third-line treatment options, this approach warrants consideration in the management of gemcitabine-refractory PDAC.
Citation Format: Daniel R. Principe, Matthew Narbutis, Sandeep Kumar, Alex Park, Navin Viswakarma, Matthew J. Dorman, Suneel D. Kamath, Hidayatullah G. Munshi, Ajay Rana. Gemcitabine primes the pancreatic tumor microenvironment for second-line immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr A20.
Abstract A32: Adipose-derived mesenchymal stem cell has the differentiation/reprogramming capacity towards two distinct cancer-associated fibroblasts
Authors: Miyazaki Yoshihiro , Kumagai Yutato , Kushige Hiroko , Shimomura Osamu , Kida Yasuyuki , Oda Tatsuya 
Published: March 2020

Abstract
Cancer-associated fibroblasts (CAFs) are well known of its heterogeneity with distinct phenotypes and functions in tumor progression. CAFs are believed to be composed mainly of resident tissue fibroblast, such as pancreas stellate cells, but bone marrow-derived mesenchymal stem cells (MSC) are also known to be their source (Ishii G et al., Adv Drug Deliv Rev 2016). Herein, we focus on adipose-derived MSC (AD-MSC) as an alternative source of CAF, as one has high reactivity of differentiation and reprogramming to the many cell types (Ronnov-Jessen L et al., J Clin Invest 1995; Sugii/Kida et al., PNAS 2010). It was reported that CAFs include myofibroblastic CAFs (myCAFs), which are found adjacent to tumor cells, and inflammatory CAFs (iCAFs), which localize farther away within the dense stroma (Ohlund, Tuveson et al., J Exp Med 2017). We investigated whether AD-MSC can be a CAF progenitor and differentiated to the different subpopulations of CAFs by employing different culture condition. To evaluate the differentiation capacity, a GFP labeled AD-MSC cell line and the human pancreatic-cancer cell line (Capan-1) were co-cultured in two condition, including direct (DR) co-culture or indirect transwell (TW) co-culture. We then performed qRT-PCR analysis and immunocytochemistry to examine their myCAF marker (ACTA-2, CTGF) or iCAF markers (IL-6, CXCL1, LIF) and compared with those in monocultured AD-MSC. We also analyzed in vitro tumor formation in DR co-culture using time-lapse imaging. In DR co-culture, the morphology of Capan-1 and AD-MSC recapitulated the clinical pancreatic cancer, with those CAF markers expressions. In the course of co-culture, sequential morphologic alterations were observed in AD-MSCs. The AD-MSC with stellate shape changed to large and small spindle-like cells through crosstalk with cancer cells. In sharp contrast, only iCAF marker expression was elevated in TW co-culture. These results collectively suggest that the AD-MSC have a potential to be progenitors of both myCAF and iCAF, explaining the heterogeneity of CAFs under the direct crosstalk with cancer cells. In the presentation, we discuss the differentiation/reprogramming capacity of AD-MSC towards two distinct CAFs (i.e., myCAF and iCAF), focusing on the cell morphology and RNA-seq analysis.
Citation Format: Yoshihiro Miyazaki, Yutato Kumagai, Hiroko Kushige, Osamu Shimomura, Yasuyuki Kida, Tatsuya Oda. Adipose-derived mesenchymal stem cell has the differentiation/reprogramming capacity towards two distinct cancer-associated fibroblasts [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr A32.
Abstract A33: Single-cell profiling reveals subclonal vulnerabilities to therapy in patient-derived 2D and organoid models
Authors: Monberg Maria E. , Pagan Vincent B. , Semaan Alexander , Lee Jaewon J. , Guerrero Paola A. , Muthuswamy Senthil K. , Maitra Anirban 
Published: March 2020

Abstract
Pancreatic ductal adenocarcinoma (PDAC) is the 3rd leading cause of cancer-related deaths in the United States. This is largely due to the fact of high propensity of patients presenting at metastatic stages resulting from symptom ambiguity and a complete lack of general population screening programs. As the overwhelming majority of patients (85%) present with surgically unresectable disease, the 5-year survival rate is dire at only ~8%. Outside of what is known of the commonly mutated genes in PDAC, which include KRAS, TP53, SMAD4, and CDKN2A, little molecular information exists that has yielded clinical knowledge that may have an impact on survival outcomes. Therefore, a concerted clinical and research paradigm shift towards higher-resolution investigations of the genomics of PDAC is an area of highest public health significance. In our laboratory, we have leveraged single-cell sequencing approaches in both cell lines and patient-derived tissues to develop models for molecular underpinnings of PDAC and as potential tools for therapeutic stratification. First, to demonstrate the ability to model cellular heterogeneity of tumor populations, single-cell RNA and DNA sequencing was applied to widely used patient-derived PDAC cell lines. Using a bioinformatics pipeline, were able to differentiate between supposedly identical cell lines that had evolved rich subclonal architecture that may provide insight into complex in silico landscapes that naturally evolve as these cells are continuously used by laboratories. We then characterized single-cell gene expression profiles of patient-derived organoids (PDOs) to understand their heterogeneous composition and applied an in silico therapeutic drug prediction model to identify and validate combinatorial strategies targeting subpopulations. These present multiple phenotypic traits similar to that of the parental tumor including histoarchitecture, oxygen biology, epigenetic marking, and differentiation status. Orthogonal validation of predicted drugs was confirmed through a high-throughput drug screen of 764 agency-approved candidates on two PDOs. This strategy demonstrated the utility of single-cell transcriptomic profiling from PDOs in effectively identifying heterogeneous enriched pathways and molecular subtypes within cultures to predict viable treatment options using a pharmacogenomic approach.
Citation Format: Maria E. Monberg, Vincent B. Pagan, Alexander Semaan, Jaewon J. Lee, Paola A. Guerrero, Senthil K. Muthuswamy, Anirban Maitra. Single-cell profiling reveals subclonal vulnerabilities to therapy in patient-derived 2D and organoid models [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr A33.
Abstract A35: Microenvironmental adaptations drive obesity-associated pancreatic cancer
Authors: Chung Katherine Minjee , Singh Jaffarguribal , Lawres Lauren , Dorans Kimberly Judith , Robbins Rebecca , Bhutkar Arjun , Babic Ana , Vayrynen Sara A. , Costa Andressa D. , Nowak Jonathan A. , Chang Daniel T. , Dunne Richard F. , Hezel Aram F. , Koong Albert C. , Wilhelm Joshua J. , Bellin Melena D. , Nylander Vibe , Gloyn Anna L. , McCarthy Mark I. , Wolpin Brian M. , Jacks Tyler , Fuchs Charles S. , Muzumdar Mandar Deepak 
Published: March 2020

Abstract
Obesity is a major modifiable risk factor for pancreatic ductal adenocarcinoma (PDAC), yet how obesity contributes to pancreatic cancer development is not well understood. Moreover, whether and at what point weight loss or other obesity-related interventions may impact PDAC progression remains largely unexplored, with significant implications for prevention and treatment. Leveraging an autochthonous genetically engineered model of PDAC, we demonstrate that obesity plays a stage-specific causal and reversible role in early PDAC progression. Molecular and histologic analyses reveal prominent microenvironmental alterations in tumors from obese mice, including increased inflammation and fibrosis and evidence for marked pancreatic islet cell adaptation. In particular, we identify aberrant expression of the peptide hormone cholecystokinin (CCK) in pancreatic islets in tumors as an adaptive response to obesity and show that islet CCK expression promotes oncogenic Kras-driven pancreatic ductal tumorigenesis. Together, these studies link obesity, changes in the local microenvironment, and tumorigenesis and implicate islet-derived hormones beyond insulin in PDAC development. Furthermore, the reversible nature of these adaptations supports the potential of antiobesity strategies to intercept PDAC early during progression.
Citation Format: Katherine Minjee Chung, Jaffarguribal Singh, Lauren Lawres, Kimberly Judith Dorans, Rebecca Robbins, Arjun Bhutkar, Ana Babic, Sara A. Vayrynen, Andressa D. Costa, Jonathan A. Nowak, Daniel T. Chang, Richard F. Dunne, Aram F. Hezel, Albert C. Koong, Joshua J. Wilhelm, Melena D. Bellin, Vibe Nylander, Anna L. Gloyn, Mark I. McCarthy, Brian M. Wolpin, Tyler Jacks, Charles S. Fuchs, Mandar Deepak Muzumdar. Microenvironmental adaptations drive obesity-associated pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr A35.
Abstract B18: Defining the role of chromatin remodeling complexes in pancreatic cancer stem cells
Authors: Ferguson Lesley Paige , Gatchalian Jovylyn , Lytle Nikki K. , Rajbhandari Nirakar , Chambers Kendall , Albini Sonia , Bruneau Benoit , Puri Lorenzo , Sander Maike , Lowy Andrew , Hargreaves Diana , Reya Tannishtha 
Published: March 2020

Abstract
Pancreatic adenocarcinoma (PDAC) is a devastating disease characterized by high rates of metastasis and poor therapeutic response. It is currently the 4th leading cause of cancer-related deaths in developed countries, and despite efforts to improve therapy, the five-year survival rate remains at 9%. Therefore, it is critical to identify new programs that drive pancreatic cancer progression and therapeutic resistance. To define new cancer dependencies, work in the Reya lab has focused on characterizing stem cell programs that drive cancer initiation, propagation, and relapse. Previously published studies have demonstrated that the fate determinant Musashi2 (Msi2) functionally marks a drug-resistant stem population in pancreatic cancer. More recent work has revealed that this aggressive subpopulation is characterized by a unique transcriptional and epigenetic profile. Given the crucial role for epigenetic regulation in development, we hypothesized that differential expression of epigenetic regulatory factors could be responsible for the establishment or maintenance of a stem cell state in pancreatic cancer. To identify epigenetic factors critical to stem function, we used a functional shRNA screen to profile the impact of inhibition of stem-enriched candidate factors on 3D growth of Msi2+ pancreatic cancer cells in vitro. From this screen, we identified the gene Smarcd3 as a critical mediator of stem cell growth in pancreatic cancer. Smarcd3 encodes Baf60c, a component of the SWI/SNF nucleosome remodeling complex with known functions in cardiac and neural development. Though Smarcd3 function has not been studied in PDAC, the SWI/SNF complex at large is known to be dysregulated in pancreatic cancer. Preliminary studies have shown that Smarcd3 inhibition leads to reduced growth of both mouse and human pancreatic cancer cells in vitro and in vivo. Current studies are ongoing to 1) elucidate the mechanism by which Smarcd3 controls growth of pancreatic cancer cells through binding of developmental transcription factors, and 2) use genetically engineered mouse models of pancreatic cancer to define the role of Smarcd3 in pancreatic cancer initiation and progression.
Citation Format: Lesley Paige Ferguson, Jovylyn Gatchalian, Nikki K. Lytle, Nirakar Rajbhandari, Kendall Chambers, Sonia Albini, Benoit Bruneau, Lorenzo Puri, Maike Sander, Andrew Lowy, Diana Hargreaves, Tannishtha Reya. Defining the role of chromatin remodeling complexes in pancreatic cancer stem cells [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr B18.
Abstract B20: KrasG12D effector dependencies in the maintenance of pancreatic ductal adenocarcinoma
Authors: Grimont Adrien , Zhao Zhen , Leach Steven D. , Chandwani Rohit 
Published: March 2020

Abstract
More than 90% of pancreatic ductal adenocarcinoma (PDAC) tumors in humans feature activating mutations in the proto-oncogene KRAS. In mice, KrasG12D mutation alone is sufficient for PanIN formation; when coupled with mutational inactivation of TP53 (Tp53R172H), PanIN formation is accelerated and these neoplastic lesions progress to invasive and metastatic disease at high frequency. Several groups have demonstrated that inactivation of mutant Kras in established PanIN and PDAC leads to redifferentiation and apoptosis of the tumor, respectively. More recently, several combinatorial genetic and pharmacologic strategies have been employed that highlight RAF kinases as key oncoeffectors for KRAS addiction, but that RAF inhibition alone demonstrates little efficiency against KRAS mutant tumors. Additionally, previous studies suggest a requirement for both C-raf and EGFR blockade or the combination of RAF-MEK or RAF-PI3K inhibitors to inhibit to tumor growth. However, a systematic evaluation of dependencies of Kras effectors in tumor maintenance has not been explicitly performed. To investigate effector dependencies in the KrasG12D setting, we have developed an organoid platform to generate isogenic lines bearing doxycycline-inducible small hairpin (sh)RNAs coupled to GFP inserted into mouse pancreatic tumor organoids derived from KPC mice. These shRNAs are directed against each of the major Kras effector molecules, including B-raf, C-raf, Pi3k, RalA, RalB, and Rac1, with Kras shRNAs and Renilla shRNA used as controls. We identified 2 effective shRNAs per target, with strong and durable inhibition of each protein observed after doxycycline treatment. To investigate the hierarchy of Kras effectors, we employed a competition assay of the shRNA organoids, and observed the drop-out of Kras, C-raf, and Rac1 shRNA-bearing tumor organoid lines. Cell number and volumetric analyses confirmed strong dependencies on Kras, C-raf, and Rac1. Chromatin accessibility and transcriptomic analyses of Kras- , C-raf- , and Rac1-depleted organoids revealed consensus features of abrogated tumor maintenance and key molecular nodes in tumor maintenance. Together, we have employed a mouse organoid platform to create a rigorous map of the requirements for the key effectors of mutant Kras, and to dissect the biologic mechanisms shared by effectors disruptive of the mutant Kras epigenetic and transcriptional landscape. In turn, we anticipate these findings can inform the subsequent development of novel therapies to address these vulnerabilities.
Citation Format: Adrien Grimont, Zhen Zhao, Steven D. Leach, Rohit Chandwani. KrasG12D effector dependencies in the maintenance of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr B20.