bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4048: Comprehensive analysis of the suppressed tumor immune microenvironment of CIN gastro-esophageal adenocarcinomas
Authors: Derks Sarah , Xu Xinsen , Klerk Leonie de , Fleitas Tania , Liu Kevin , Liu Yang , Margolis Claire A. , Dietlein Felix , Chiaravalli Anna Maria , Silva Annacarolina da , Freeman Gordon , Rodig Scott J. , Allen Eliezer M. Van , Li Bo , Fu Jingxin , Wang Jin , Liu Shirley X. , Bass Adam J. 
Published: August 2018

Abstract
Background and aims: Gastro-esophageal adenocarcinoma (GEA) is a common and lethal disease where immune checkpoint inhibitors have demonstrated efficacy within a minority of patients. Prior studies have identified distinct molecular classes of GEA, characterized by specific features that would be predicted to influence responses to checkpoint therapy. We here perform a comprehensive analysis of tumor immune associations in GEAs to further define the tumor immune microenvironment in distinct classes of GEA and to identify additional candidate mediators of immune evasion that may impact response to immunotherapy efficacy. Methods: Tumor immune interactions in GEAs were studied first using computational analyses to infer immune cell subsets from RNAseq data generated from The Cancer Genome Atlas (TCGA). These data were complemented by additional focused studies spanning immunohistochemistry, gene expression profiling and flow cytometry on archival tissue samples and from freshly resected GEA tumor samples. Results: Our results confirmed substantial heterogeneity in the composition of the tumor immune microenvironment between distinct GEA subtypes. As shown earlier, tumors with microsatellite instability (MSI) or Epstein-Barr virus (EBV) harbored larger T cell infiltrates in contrast to those with chromosomal instability (CIN), the most common class of GEA. We then focused greater attention on the CIN cohort, finding a spectrum of phenotypes including tumors with ‘immune hot' and ‘immune cold' states. The ‘hot' cases were more often from Western patients and had greater degrees of DNA methylation. Notably, these tumors often showed co-expression of secondary immune checkpoint proteins, as confirmed by flow cytometry. There was no association between number of infiltrating T cells and mutational or neoantigen load within the CIN GEA subgroup. Immunological cold CIN GEAs were characterized by a higher level of chromosomal instability, enrichment of cell cycle pathways, specifically amplification of cyclin E1, CCNE1, and enrichment of an unfolded protein response.
Citation Format: Sarah Derks, Xinsen Xu, Leonie de Klerk, Tania Fleitas, Kevin Liu, Yang Liu, Claire A. Margolis, Felix Dietlein, Anna Maria Chiaravalli, Annacarolina da Silva, Gordon Freeman, Scott J. Rodig, Eliezer M. Van Allen, Bo Li, Jingxin Fu, Jin Wang, Shirley X. Liu, Adam J. Bass. Comprehensive analysis of the suppressed tumor immune microenvironment of CIN gastro-esophageal adenocarcinomas [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 4048.
Abstract 4063: Target immunosuppressive myeloid cells to enhance cancer immunotherapy
Authors: Lu Xin 
Published: August 2018

Abstract
A significant fraction of advanced prostate cancer (PCa) patients treated with androgen deprivation therapy (ADT) experience relapse with relentless progression to lethal metastatic castration-resistant prostate cancer (mCRPC). Immune checkpoint blockade (ICB) using antibodies against cytotoxic-T-lymphocyte-associated protein 4 (CTLA4) or programmed cell death 1/ programmed cell death 1 ligand 1 (PD1/PD-L1) generates durable therapeutic responses in a significant subset of patients across a variety of cancer types. However, mCRPC showed overwhelming de novo resistance to ICB, motivating a search for targeted therapies that overcome this resistance. Myeloid-derived suppressor cells (MDSCs) are known to play important roles in tumor immune evasion. Circulating MDSC abundance correlates with PSA levels and metastasis in PCa patients. Mouse models of PCa show that MDSCs (CD11b+ Gr1+) promote tumor initiation and progression. These observations prompted us to hypothesize that robust immunotherapy responses in mCRPC may be elicited by the combined actions of ICB agents together with targeted agents that neutralize MDSCs yet preserve T cell function. Here we developed a novel chimeric mouse model of mCRPC to efficiently test combination therapies in an autochthonous setting. Combination of anti-CTLA4 and anti-PD1 engendered only modest efficacy. Targeted therapy against mCRPC-infiltrating MDSCs, using multikinase inhibitors such as cabozantinib and dactolisib, also showed minimal anti-tumor activities. Strikingly, primary and metastatic CRPC showed robust synergistic responses when ICB was combined with MDSC-targeted therapy. Mechanistically, combination therapy efficacy stemmed from the upregulation of IL-1ra and suppression of MDSC-promoting cytokines secreted by PCa cells. These observations illuminate a clinical path hypothesis for combining ICB with MDSC-targeted therapies in the treatment of mCRPC.
More recently, through mass spectrometry we uncovered a new mechanism by which MDSCs employ potent reactive nitrogen species (RNS) to inactivate key molecules in the T cell activation signaling pathway. Agents that neutralize RNS generate significant anti-tumor effect when combined with ICB in prostate cancer.
Citation Format: Xin Lu. Target immunosuppressive myeloid cells to enhance cancer immunotherapy [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 4063.
Abstract 4065: Suppression of myeloid cell arginase activity leads to therapeutic response in Kras mutant lung cancer by activating anti-tumor immunity
Authors: Miret Juan J. , Kirschmeier Paul , Wu Min , Huang Wei , Walker William , Palakurti Sangeetha , Saccomano Nick , Hammerman Peter S. , Wong Kwok-kin , Akbay Esra 
Published: August 2018

Abstract
Metabolic changes in the tumor microenvironment impair the generation of an efficient anti-tumor immune response. Reduction of specific amino acids like arginine and tryptophan limit anti-tumor immune responses, contributing to a tumor generated immune suppressive environment. Arginine levels are critical for lymphocyte proliferation and function, and they are regulated by arginase 1 & 2 and nitric oxide synthase. Arginase 1 activity has been associated with most of the immunosuppressive effects resulting from arginine depletion and the role of arginase activity in lung tumor maintenance has not been investigated in clinically relevant established tumor models. RNA sequencing of sorted cell populations from immunocompetent genetically engineered KRAS G12D mutant mouse lung tumors, showed that arginase 1 expression is elevated in the myeloid cell population in the tumor microenvironment. Ex vivo analysis demonstrated that myeloid derived suppressor cell (MDSCs) from mouse tumors hindered T cell function by depleting arginine. These MDSCs expressed elevated levels of arginase 1, and inhibition of its activity by an Arg1/2 inhibitor, compound 9, restored effector T cell function. Treatment of a genetically engineered KRAS mutant mouse model with compound 9 increased arginine levels in blood and tumor and led to an increased number of tumor T cells and a significant reduction in tumor volume after 1 week of treatment. Compound 9 had no growth inhibitory activity across several murine and human KRAS mutant lung cancer cell lines in vitro. We also determined by immunohistochemistry that elevated levels of arginase 1 were expressed in granulocytic myeloid cells from KRAS mutant lung cancer patient samples. Given the data reported here and by others, an arginase inhibitor with excellent potency and in vivo target engagement could represent an important new immunotherapeutic agent. We have recently discovered and are fully characterizing molecules that demonstrate excellent potency and selectivity along with oral bioavailability in rodents that provide good arginase target coverage at modest doses.
Citation Format: Juan J. Miret, Paul Kirschmeier, Min Wu, Wei Huang, William Walker, Sangeetha Palakurti, Nick Saccomano, Peter S. Hammerman, Kwok-kin Wong, Esra Akbay. Suppression of myeloid cell arginase activity leads to therapeutic response in Kras mutant lung cancer by activating anti-tumor immunity [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 4065.
Abstract 4067: Toll-like receptor 2 deficiency enhances KRAS-driven lung cancer
Authors: Liu Chia-Hsin 
Published: August 2018

Abstract
Chronic infection and inflammation have been suggested to have a strong association with lung cancer in clinical and epidemiologic studies. Toll-like receptor 2 (TLR2) mediates inflammatory response and is essential in regulating innate and adaptive immunity. TLR2 has also been reported to play either pro-tumorigenesis or tumor-suppressive role depending on the oncogenic driver mutations and cell types. However, the role of TLR2 in lung cancer, especially in the lung adenocarcinoma harboring KRAS mutations, remains unknown. In an analysis using human lung adenocarcinoma cohort (TCGA RNAseq dataset), our results revealed that KRAS-mutant lung tumors showed lower TLR2 mRNA expression than the paired adjacent normal lung tissue. Furthermore, lung adenocarcinoma patients with lower TLR2 expression displayed worse survival outcome. To functionally test the role of TLR2 during KRAS-driven lung tumorigenesis, we generated a mouse model of lung adenocarcinoma mutated for K-ras, with and without TLR2 inactivation (K-rasG12D/+ TLR2-/- and K-rasG12D/+TLR2+/+, respectively). Interestingly, the tumor number and tumor area significantly increased in K-rasG12D/+ TLR2-/- mice compared to K-rasG12D/+TLR2+/+ mice. In addition, the inflammatory cells in bronchoalveolar lavage (BAL), especially the alveolar monocytes, significantly increased in K-rasG12D/+ TLR2-/- mice. Microdissected lung tumors from K-rasG12D/+ TLR2-/- mice showed significantly higher inflammatory chemokines and cytokines gene expression (Ccl1, Ccl2, Cxcl1, Cxcl2, Cxcl5, Csf1, IL-6, Tnf) than those from K-rasG12D/+TLR2+/+mice. Additionally, Cxcl1 was significantly higher in K-rasG12D/+ TLR2-/- when BAL fluid was analyzed for cytokines/chemokines by Luminex assays. Our results suggest that TLR2 deficiency may promote KRAS-mutation driven lung tumorigenesis through increased cancer-related inflammation. Furthermore, the expression may serve as a prognostic biomarker for which the lower TLR2 expression is associated with worse survival outcome in lung adenocarcinoma patients with KRAS mutation.
Citation Format: Chia-Hsin Liu. Toll-like receptor 2 deficiency enhances KRAS-driven lung cancer [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 4067.
Abstract 4077: A new mouse model of gastric adenocarcinoma: A valuable tool for preclinical studies
Authors: Till Jacob , Addai Prince , Bhagwat Neha , Yee Stephanie , Carpenter Erica , Yoon Sam , Ryeom Sandra 
Published: August 2018

Abstract
We recently generated the first model of metastatic mixed-type gastric adenocarcinoma that closely recapitulates the human disease. Our model combines conditional loss of E-cadherin (Cdh1fl/fl) and p53 (Trp53fl/fl) with oncogenic Kras (KrasLSL-G12D/+) activation and yellow fluorescence protein (Rosa26LSL-YFP/LSL-YFP) expression in cells of the gastric parietal cell lineage (Atp4b-Cre). Median survival is 76.5 days (range 64-91 days, SD 7.2) with all mice developing local lymph node metastases and lung metastases, half developing paratracheal lymph node metastases, and 20% developing liver metastases. We previously provided proof of concept for the preclinical utility of our model by demonstrating extended survival upon treatment with a MEK inhibitor (PD0325901). Here we demonstrate the utility of this model to investigate the role of the microbiome in gastric carcinogenesis and to determine the use of circulating tumor cells (CTCs) as biomarkers of metastatic disease. The specific pathogen H. pylori is known to be causal in gastric adenocarcinoma. Further, many studies have implicated the microbiome in colon carcinogenesis. However, no studies have investigated the role of the normal microbiome in gastric carcinogenesis in the absence of H. pylori infection. We treated our model of mixed-type gastric adenocarcinoma with a commonly utilized antibiotic cocktail to deplete the gut microbiota and confirmed depletion of the microbiota by qPCR in stomach and fecal contents at necropsy. Microbiome depletion resulted in a 7.5-day increase in median survival (n=6) over vehicle treated mice (n=5, p=0.04). These data suggest a role for the normal microbiota in gastric cancer progression regardless of H. pylori infection. Given the broadly metastatic phenotype of our model, we examined whether the number of CTCs correlated with metastatic burden. Because our gastric cancer model incorporated a yellow fluorescence protein (YFP) as a marker of tumor cells, we used flow cytometry to measure CTCs in cardiac blood samples from terminal mice. We detected CTCs (defined as DAPI-;CD45-;YFP+) in all terminal mice and correlated CTC counts with lung metastatic burden. Mice with macrometastatic disease in the lung had &gt;90 CTCs per 100 μl blood (n=3) as compared to mice with micrometastatic disease of the lung which showed &lt;15 CTCs per 100 μl blood (n=4, p=0.008). These data suggest that our new mouse model of metastatic gastric adenocarcinoma offers a valuable tool for a variety of preclinical studies.
Citation Format: Jacob Till, Prince Addai, Neha Bhagwat, Stephanie Yee, Erica Carpenter, Sam Yoon, Sandra Ryeom. A new mouse model of gastric adenocarcinoma: A valuable tool for preclinical studies [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 4077.
Abstract 4091: Knockout of genes in the DNA mismatch repair pathway to model colorectal cancer hypermutation
Authors: Jin Abbey Y. , Westcott Peter , Smith Olivia , Cruz Amanda , Beytagh Mary Clare , Jacks Tyler 
Published: August 2018

Abstract
Human colorectal cancer (CRC) is characterized by a high burden of somatic mutations, particularly in tumors harboring defects in the DNA mismatch repair (MMR) pathway. However, genetically-engineered mouse models (GEMMs) of cancer to date harbor a very low burden of mutations. Importantly, recent clinical trials have shown that MMR deficient tumors respond favorably to anti-PD-1 immune checkpoint blockade, and it is thought that PD-1 suppression reinvigorates existing T cell clones against neo-antigens associated with hypermutation in these tumors. In order to develop a more clinically relevant GEMM of CRC in which to study the immune response, MMR genes will be knocked out via CRISPR-Cas9 to induce hypermutation. To identify optimal Cas9 single guide RNAs (sgRNAs) against the MMR genes Msh2, Msh3, Msh6, and Mlh1, sgRNAs were designed using the Broad Institute algorithm and knockout efficiency assessed in a reporter cell line by Western blot. In order to induce colon tumors in vivo, colonoscopy-guided submucosal injection was employed to deliver lentivirus encoding sgRNAs against a MMR gene and Apc into mice carrying a constitutive Cas9 allele. Apc is inactivated in over 80% of human CRC, and is an initiating event in CRC in humans and mice. Using a sgMsh2-sgApc dual targeting lentivirus, we were able to efficiently generate colon tumors harboring complete knockout of Apc and near complete knockout of Msh2. Deep sequencing of the targeted loci revealed predominantly loss-of-function frameshift mutations at Apc and Msh2, but also a high degree of polyclonality. Lower titer injections of virus will be explored to induce more clonal tumors. Mlh1, Msh3, and Msh6 will also be targeted in vivo, and the mutational effects of MMR gene loss will be assessed by whole-exome sequencing of tumors. This rapid and flexible GEMM of hypermutant CRC may facilitate a more clinically relevant assessment of the role of the immune system in CRC development, as well as provide improved platforms for testing immunotherapies.
Citation Format: Abbey Y. Jin, Peter Westcott, Olivia Smith, Amanda Cruz, Mary Clare Beytagh, Tyler Jacks. Knockout of genes in the DNA mismatch repair pathway to model colorectal cancer hypermutation [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 4091.
Abstract 4097: Maintenance of primary human colorectal cancer microenvironment using a perfusion bioreactor-based 3D culture system
Authors: Manfredonia Celeste , Muraro Manuele Giuseppe , Hirt Christian , Mele Valentina , Governa Valeria , Papadimitropoulos Adam , Daester Silvio , Soysal Savas D. , Droeser Raoul A. , Mechera Robert , Oertli Daniel , Rosso Raffaele , Bolli Martin , Terracciano Luigi M. , Spagnoli Giulio C. , Martin Ivan , Iezzi Giandomenica 
Published: August 2018

Abstract
Colorectal cancer (CRC) is a leading cause of cancer-related death, often diagnosed at advanced stages. Conventional chemotherapeutic regimens have limited success rates, and a major challenge is represented by the lack of adequate in vitro models predicting patient responsiveness to defined treatments, possibly guiding therapeutic decisions. Non-malignant cells, including mesenchymal and immune cells, critically affect development, progression and drug responsiveness of human CRC. However, tumor drug responses are still evaluated on culture systems, such as 2D tumor cell monocultures or on tumor xenografts, which do not preserve all cellular components of in vivo tumor microenvironment.In this work, we have investigated the suitability of a perfusion-based bioreactor for 3D culture of primary CRC samples. Freshly excised CRC specimens were cut into fragments, inserted between two collagen type I sponges in a “sandwich-like” format and cultured for three days in a perfused-based system or under static conditions.We show that cultures under perfusion result in significantly higher maintenance of tissue integrity as compared to static cultures, with preservation of whole tumor microenvironment components, including cancer cells, mesenchymal stromal cells and a fraction of immune cells. Tumor tissues cultured under perfusion displayed an almost intact architecture with viable and proliferating tumor cells. Stromal cells were also maintained in proportions similar to those of original tumors and were fully viable, as indicated by their responsiveness to microenvironmental stimuli, such as IL-17. In addition, immune cells were also partially preserved, and were capable to release effector cytokines upon activation. Importantly, perfusion-based cultures proved suitable for testing sensitivity of primary tumor cells to chemotherapies currently in use for CRC and revealed heterogeneous responsiveness across different samples.
[C.M. and M.G.M. contributed equally to this work.]
Citation Format: Celeste Manfredonia, Manuele Giuseppe Muraro, Christian Hirt, Valentina Mele, Valeria Governa, Adam Papadimitropoulos, Silvio Daester, Savas D. Soysal, Raoul A. Droeser, Robert Mechera, Daniel Oertli, Raffaele Rosso, Martin Bolli, Luigi M. Terracciano, Giulio C. Spagnoli, Ivan Martin, Giandomenica Iezzi. Maintenance of primary human colorectal cancer microenvironment using a perfusion bioreactor-based 3D culture system [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 4097.
Abstract 4103: Utility of multispectral optoacoustic tomography in imaging pancreatic tumors using a uPA-probe
Authors: Chiba Akiko , Samykutty Abhilash , Smith Mary , McNally Lacey 
Published: August 2018

Abstract
Background: Pancreatic cancer has the lowest 5-year survival rate of all cancer types. Current methods of pancreatic cancer screening, diagnosis and treatment have failed to improve outcome in the last few decades. Potential explanation for this failure may be explained by the hypovascularized nature of pancreatic cancer, making conventional chemotherapy and imaging modality suboptimal. There is a potential for improved imaging using a new imaging modality, multispectral optoacoustic tomography (MSOT). We hypothesize that a using urokinase plasminogen activator (uPA) contrast agent while using MSOT imaging would improve identification of orthotopic pancreatic cancer in xenografts. Methods: Expression of uPA receptor (uPAR) were evaluated in pancreatic tumor cell lines, Panc1, S2CP9, MiaPaca-2 and S2VP10 using western blot. A uPA targeted contrast agent was created using standard bioconjugation methods with the Hilite 750 near infrared (NIR) dye. Five SCID mice were orthotopically implanted with S2CP9 (1.5 x 105) and 5 additional SCID mice were implanted with MiaPaCa2 (2.0 x 106) pancreatic tumor cells. When tumor size reached 3mm, 200µL of 100 nM uPA-750 probe or 750 dye alone was injected into mice. Biodistribution and accumulation of the uPA-750 probe was visualized using MSOT imaged at 2-hour intervals for 8 hours and at 24 hours. Accumulation of uPA-750 probe was evaluated in the tumor, liver, and kidney using NIR fluorescent imaging. Results: All pancreatic cancer cell line expressed uPAR with the highest in S2CP9 cells (3.0x), S2VP10 (2.5x), Panc1 (1.77x) and MiaPaca-2 (1.3x). In vivo, peak intensity of uPA-750 probe was successfully detected using MSOT at 4 hours, within the pancreas tumor in slices from 37mm-41mm. uPA-750 probe was undetectable within the tumor after 8 hours. Using ex vivo NIR fluorescence imaging, uPA-probe signal was detected only within the pancreatic tumor, however, no signal was detected in the liver or kidney. Conclusion: This study demonstrated MSOT imaging using uPA-probe as a contract agent may lead to improved pancreatic cancer detection which may lead to improvement in overall outcome.
Citation Format: Akiko Chiba, Abhilash Samykutty, Mary Smith, Lacey McNally. Utility of multispectral optoacoustic tomography in imaging pancreatic tumors using a uPA-probe [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 4103.