bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract B28: Novel combination treatment designed to target both metastatic cells and proliferation in pancreatic ductal adenocarcinoma
Authors: Karl Michelle , Russo Gabriella , Starich Bartholomew , Tan Haotian , Wirtz Denis
Published: March 2020

Pancreatic cancer is the 4th most common cause of cancer-related deaths in the United States, with only a 7-9% 5-year survival rate. While there are a few combination treatments that have been shown to increase overall survival by several months, gemcitabine monotherapy, which has been used to treat PDAC since 2006, is still the most commonly administered first-line treatment. Our objective is to improve patient survival by providing a novel combination therapy designed to inhibit the growth of solid tumors and prevent metastatic cancer cells from reaching secondary organs. Our lab has recently shown that secreted interleukin 6 (IL-6) and interleukin 8 (IL-8) can induce a migratory phenotype in tumorigenic, metastatic cancer cells in triple-negative breast cancer models. Cells exposed to these cytokines display enhanced invasion through stromal environments, and this phenotype can be reversed by blocking the IL-6 and IL-8 receptors with the combined treatment of tocilizumab and reparixin. We hypothesized that this simultaneous blocking of IL-6 and IL-8 receptors would improve PDAC patient outcomes when used in combination with gemcitabine by targeting both proliferation and metastasis. Preliminary results show that this combination treatment has a positive effect in in vivo PDAC models. Our novel treatment combination was able to significantly reduce the tumor size, exceeding that seen from gemcitabine monotherapy. In addition, the triple combination reduced the metastatic burden and normalized the effect of the treatment among the mice in the group.

Citation Format: Michelle Karl, Gabriella Russo, Bartholomew Starich, Haotian Tan, Denis Wirtz. Novel combination treatment designed to target both metastatic cells and proliferation in 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 B28.
Abstract B31: Type 1 conventional dendritic cells are progressively and systemically dysregulated early in pancreatic carcinogenesis
Authors: Lin Jeffrey H. , Huffman Austin P. , Furth Emma E. , Vonderheide Robert H.
Published: March 2020

Dendritic cell (DC) dysregulation in cancer has long been hypothesized to be a tumor-associated phenomenon. Using the KPC autochthonous mouse model of pancreatic ductal adenocarcinoma, we reveal that dysfunction of type 1 conventional DCs (cDC1s)—critical mediators of antitumor T-cell immunity—instead develops in the preinvasive stage of carcinogenesis and impacts the host systemically prior to malignancy. Both cDC1 survival and function are impacted, with cDC1s suspended in a state of semi-maturation in which genes involved in response to inflammation and proteasomal degradation are successfully upregulated while genes encoding T cell-polarizing cytokines necessary for T-cell activation fail to be induced. cDC1 dysfunction subsequently impairs CD8+ T-cell activation in vivo. However, this defect remains reversible even following progression to invasive cancer. CD40 activation induces an IFNg response signature that drives cDC1 maturation and migration to draining lymph nodes, restoring CD8+ T-cell activation to normal levels. This study therefore reveals the unexpected depths of cDC1 dysregulation in carcinogenesis but nevertheless elaborates therapeutically tractable strategies towards cDC1 repair.

Citation Format: Jeffrey H. Lin, Austin P. Huffman, Emma E. Furth, Robert H. Vonderheide. Type 1 conventional dendritic cells are progressively and systemically dysregulated early in pancreatic carcinogenesis [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 B31.
Abstract B46: Targeting pancreatic cancer organoids with dual BET and CBP/P300 inhibitor NEO2734
Authors: Radulovich Nikolina , Tamblyn Laura , Seo Heewon , Haibe-Kains Benjamin , Lupien Mathieu , Gilles Francis , Tsao Ming S.
Published: March 2020

Pancreatic ductal adenocarcinoma (PDA) has a dismal prognosis due to largely ineffective therapeutics available for this disease. Recently, inhibitors of bromodomain and extraterminal domain (BET) inhibitors have been shown to have therapeutic efficacy against various malignancies, including PDA. Here we present data on sensitivity of PDA patient-derived organoids (PDO) to a novel dual BET and CBP/P300 inhibitor, NEO2734 (Epigene Therapeutics Inc.). Our cell viability screen on a panel of 30 PDOs derived from PDA patient and xenograft tumor tissue revealed differential drug sensitivities to NEO2734 inhibitor. Antitumor effect of NEO2734 on the most sensitive PPTO.2 model was further confirmed in vivo using patient-derived xenograft PPTO.2 model. To identify potential biomarkers associated with differential sensitivities of PDA PDOs to NEO2734 inhibitor, we generated gene expression profiles from 13 PDOs derived from primary patient tumors. Using the probabilistic concordance index (C-index), 13 genes (Bonferroni corrected P<1.0E-10) were identified as potential therapeutic targets. Among the biomarkers identified, we found three associations with known BET inhibitor target genes, including CA9 (C-index= 0.38, PBonferroni= 2.7E-19), which is known to be downregulated by BET inhibitor and coexpressed with the target gene BRDT. Furthermore, the biomarker SLC7A2 (0.28, 3.4E-37) has a known genetic interaction with BRD4, and ABCB6 (0.31, 1.5E-27) is predicted to be coexpressed with CREBBP. Overall, this work reveals that dual BET and CBP/P300 inhibitor, NEO2734, could be a novel therapeutic option for a subset of PDA patients.

Citation Format: Nikolina Radulovich, Laura Tamblyn, Heewon Seo, Benjamin Haibe-Kains, Mathieu Lupien, Francis Gilles, Ming S. Tsao. Targeting pancreatic cancer organoids with dual BET and CBP/P300 inhibitor NEO2734 [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 B46.
Abstract B52: The T-cell architecture of pancreatic ductal adenocarcinoma
Authors: Sivakumar Shivan , Shah Enas Abu , Ahern David , Mangal Nagina , Reddy Srikanth , Rendek Aniko , Soonawalla Zahir , Silva Michael , Middleton Mark , Dustin Michael
Published: March 2020

Pancreatic cancer has the worst prognosis of any human malignancy. Our recent work has shown that immune infiltrate by transcriptomics and histopathology can predict prognosis after a Whipple’s operation, with lymphocyte infiltration being the most important prognostic marker. We have profiled T cells within primary pancreatic cancer to understand the T-cell architecture within the tumor. We have used a 37-marker T cell-focused panel to study the immune infiltrate. We see a diverse immunosuppressive immune microenvironment within the primary tumor. There is a complex architecture of macrophages, neutrophils, and T cells. The commonest CD4 T cells in the microenvironment are Tregs. There are potential novel therapeutic strategies for Tregs using unique checkpoint inhibitors. The CD8 T cells have PD-1 activity but are not activated or proliferating. The poor prognosis of pancreatic cancer could be explained by the immunosuppressive microenvironment, but there are opportunities to drug Tregs in this disease.

Citation Format: Shivan Sivakumar, Enas Abu Shah, David Ahern, Nagina Mangal, Srikanth Reddy, Aniko Rendek, Zahir Soonawalla, Michael Silva, Mark Middleton, Michael Dustin. The T-cell architecture 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 B52.
Abstract B58: A phase I/II study of durvalumab and stereotactic radiotherapy in locally advanced pancreatic cancer
Authors: Tuli Richard , Nissen Nicholas , Lo Simon , Tighiouart Mourad , Placencio Veronica , Hendifar Andrew
Published: March 2020

Purpose/Objective: Blockade of the PD-1/PD-L1 pathway with radiotherapy (RT) can enhance both local and systemic control in varying tumor types. Yet, no significant responses have been seen in pancreatic cancer (PC). We have previously shown that RT induces PD-1 and PD-L1 in PC following upregulation of interferon-gamma. This mechanism of adaptive immune resistance by PC may serve as an ideal therapeutic target for combined RT and PD-L1 blockade. We report interim results of an ongoing phase 1/2 clinical trial in locally advanced (LA) and borderline resectable (BR) PC (NCT03245541).

Materials/Methods: Patients with LA or BR PC treated with standard-of-care gemcitabine and nab-paclitaxel for 3 to 6 cycles were enrolled. Treatment consisted of durvalumab (750 mg Q14 days) on D1. Stereotactic ablative radiotherapy (SABR; 6.6 Gy/fraction) was delivered every other day x 5 fractions beginning D8. Durvalumab continued as maintenance Q14 days until resection or progression. The run-in phase I utilized a standard 3+3 design prior to phase 2 expansion. Dose-limiting toxicities (DLTs), adverse events (AEs), and serious adverse events (SAEs) were assessed during the first 10 weeks of study treatment. CT scans were obtained every 2 months for response assessment. Endoscopic research biopsies were obtained pre- and 6-8 weeks post-SABR, and weekly blood samples were obtained on D1, weekly for 10 weeks, and then every 2 months until resection or progression to assess for immune correlates of response.

Results: From 8/2017-5/2019, 18 of 30 planned patients were enrolled of whom 13 (72%) were LA and 5 (28%) were BR. Median age was 70 and 44% were female. No DLTs were identified in the phase 1 run in, and enrollment in the phase 2 study continues. Median follow-up from diagnosis is 14 months (range 6-26 months). Median cycles of chemotherapy received prior to enrollment were 4. Grade 3 toxicities have been identified in 2 patients (nausea, anorexia). No patients experienced dose-limiting toxicities. Median PFS was 14 months with median OS not reached. 9 of 18 patients have undergone resection and all were margin negative. BOR: PR (54%); CR (6%), SD (34%), PD (6%).

Conclusion: To our knowledge, this is the first report of a PD-L1 inhibitor-RT combination in LA PC. The regimen was safe, well tolerated and appears to be clinically active with high rates of margin-negative resection.

Citation Format: Richard Tuli, Nicholas Nissen, Simon Lo, Mourad Tighiouart, Veronica Placencio, Andrew Hendifar. A phase I/II study of durvalumab and stereotactic radiotherapy in locally advanced 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 B58.
Abstract C01: Porcupine inhibition redirects mitochondrial metabolism in Wnt-dependent pancreatic cancer
Authors: Aguilera Kristina Y. , Riahi Rana , Saadat Edris A. , Lay Anna R. , Le Thuc , Donahue Timothy R. , Radu Caius , Dawson David W.
Published: March 2020

Wnt/β-catenin signaling plays important roles in pancreatic ductal adenocarcinoma (PDA) tumor initiation and progression via broad-ranging effects on proliferation, differentiation, survival, and stemness. Although Wnt has been shown to promote glycolysis in colon cancer, its role in regulating metabolism in PDA has not been well explored. For this study, RNF43-mutant cell lines were selected as exemplars of ligand-dependent autocrine Wnt signaling in PDA. These cell lines harbor an inactivating mutation in RNF43 that confers Wnt growth-dependency and response to LGK974, a PORCN inhibitor that blocks Wnt ligand secretion and signaling. Global transcriptomic, proteomic, and metabolomic analysis revealed several metabolites and putative mediators of metabolism that are directly or indirectly linked to autocrine Wnt signaling. Pharmacologic inhibition of Wnt by LGK974 led to the accumulation of pyruvate and lactate, as well as reduced tricarboxylic acid cycle metabolites and decreased mitochondrial membrane potential as measured by tetramethylrhodamine and JC-1 assays. These metabolic changes were accompanied by cell cycle arrest and downregulation of transcriptional programs involved in cell cycle progression, DNA replication, and nucleotide metabolism. Importantly, LGK974 results were phenocopied by siRNA-mediated knockdown of WNT7B and rescued with WNT3A conditioned media. Thus, inhibition of mitochondrial oxidative phosphorylation by LGK974 in RNF43-mutant PDA appears linked to its inhibition of canonical Wnt signaling, an adaptation and potential metabolic vulnerability that could be leveraged to therapeutic advantage via combinatorial strategies. Altogether, these results suggest tissue context and mechanisms of Wnt pathway activation may profoundly influence its role in regulating cancer metabolism.

Citation Format: Kristina Y. Aguilera, Rana Riahi, Edris A. Saadat, Anna R. Lay, Thuc Le, Timothy R. Donahue, Caius Radu, David W. Dawson. Porcupine inhibition redirects mitochondrial metabolism in Wnt-dependent 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 C01.
Abstract C06: Cholesterol deprivation induces TGFβ signaling to promote basal differentiation in pancreatic cancer
Authors: Gabitova Linara , Peri Suraj , Francescone Ralph , Franco-Barraza Janusz , Shah Neelima , Nicolas Emmanuelle , Handorf Elizabeth A. , Cai Kathy Q. , Sloma Ido , Chiaverelli Rachel , Moffitt Richard , Golemis Erica A. , Fang Carolyn , Lynch Shannon , Cukierman Edna , Astsaturov Igor
Published: March 2020

Oncogenic transformation alters the metabolism of cellular nutrients to sustain tumor growth. We here define a mechanism by which modifications in cholesterol metabolism control the formation of pancreatic ductal adenocarcinoma (PDAC). Disruption of distal cholesterol biosynthesis by means of conditional inactivation of Nsdhl in mice bearing a tumor-inducing Kras mutation (KrasG12D) prevented PDAC formation in the context of a heterozygous Trp53f/+ genotype without impairing normal pancreatic development. In mice with pancreatic Nsdhl ablation and homozygous loss of Trp53, the emerging tumors presented with the aggressive basal (mesenchymal) phenotype as opposed to the classic (glandular) PDAC. This paralleled significantly reduced expression of cholesterol metabolic pathway genes in human basal PDAC subtype. Mechanistically, we demonstrate that genetic or metabolic reduction in cellular cholesterol induces the expression of transforming growth factor beta (TGF) and activates pro-mesenchymal effectors in human and murine PDAC, providing a direct transcriptional mechanism by which cholesterol metabolism can condition tumor differentiation. Activity of TGF beta pathway estimated via pSMAD2 expression in surgical PDAC samples inversely correlated with patients’ blood cholesterol levels, especially in patients taking cholesterol-lowering statins. Conclusions: Low levels of cellular cholesterol induce autocrine TGF beta signaling in PDAC. Malnutrition or cholesterol-lowering statins may be mechanistically linked to basal PDAC differentiation.

Citation Format: Linara Gabitova, Suraj Peri, Ralph Francescone, Janusz Franco-Barraza, Neelima Shah, Emmanuelle Nicolas, Elizabeth A. Handorf, Kathy Q. Cai, Ido Sloma, Rachel Chiaverelli, Richard Moffitt, Erica A. Golemis, Carolyn Fang, Shannon Lynch, Edna Cukierman, Igor Astsaturov. Cholesterol deprivation induces TGFβ signaling to promote basal differentiation in 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 C06.
Abstract C10: Glutamine deprivation triggers hexosamine salvage in pancreatic cancer cells
Authors: Campbell Sydney L. , Mesaros Clementina A. , Tsang Tiffany , Noji Michael , Kruijning Salisa , Trefely Sophie , Izzo Luke , Blair Ian A. , Wellen Kathryn E.
Published: March 2020

Pancreatic ductal adenocarcinoma (PDA) remains one of the most difficult cancers to effectively treat. Over 90% of PDA are driven by oncogenic KRAS, which leads to metabolic rewiring in the cell, including increased glucose uptake and increased flux through the hexosamine biosynthesis pathway (HBP). The HBP, which branches off from glycolysis at fructose-6-phosphate and also requires glutamine, acetyl-CoA, and uridine triphosphate, is responsible for synthesizing uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), a major substrate for glycosylation in the cell. UDP-GlcNAc can also be generated through recycling of GlcNAc via N-acetylglucosamine kinase (NAGK). Glycans are important for maintaining protein homeostasis and cell signaling. However, while there is increased HBP flux in PDA and glycosylation is elevated in a range of cancers, how this is regulated and the functional significance of increased glycosylation in cancer are not well understood. Because of the multiple metabolic inputs required for UDP-GlcNAc synthesis, the HBP has been proposed as a nutrient sensing pathway. Surprisingly, however, we found that PDA cells robustly maintain both O-GlcNAc and N-glycosylation when exposed to nutrient deprivation. The enzyme N-acetylglucosamine kinase (NAGK) is upregulated under low glutamine conditions, and through stable isotope tracing studies, we demonstrate that PDA cells are able to switch to use of the salvage pathway over the HBP for generation and maintenance of the UDP-GlcNAc pool via NAGK. Together, this work points to a mechanism of metabolic flexibility in generating UDP-GlcNAC that allows PDA cells to grow in a nutrient-poor environment.

Citation Format: Sydney L. Campbell, Clementina A. Mesaros, Tiffany Tsang, Michael Noji, Salisa Kruijning, Sophie Trefely, Luke Izzo, Ian A. Blair, Kathryn E. Wellen. Glutamine deprivation triggers hexosamine salvage in pancreatic cancer 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 C10.
Abstract C13: A “mouse hospital” for preclinical testing of diagnostic and treatment modalities in pancreatic ductal adenocarcinoma (PDA)
Authors: Clendenin Cynthia , Sor Rina , McMenamin Deirdre , Stanger Ben Z. , Beatty Gregory , Vonderheide Robert H.
Published: March 2020

A major challenge for cancer drug development is deciding which compounds to bring forward to clinical trials. Mouse models provide a helpful prescreening tool, but xenograft and subcutaneous models can be poorly predictive of a treatment’s efficacy against a naturally occurring tumor. Preclinical models that more accurately reproduce all the features of a tumor, including its microenvironment, may provide a more accurate readout for response to therapy. Genetically engineered mouse (GEM) models of pancreatic ductal adenocarcinoma (PDA) have been developed that exploit the fact that virtually all PDAs exhibit activating mutations in Kras (exon 12) and that over 75% have mutations in p53. These models use a pancreas-specific Cre recombinase to create mutations in Kras and p53 in the pancreatic epithelium. Tumors in these “KPC” mice recapitulate the salient clinical, histopathologic, and molecular features of the human disease. Importantly, the tumor arises in an immune-competent host. A variant of the KPC model, known as KPCY, also has a fluorescent lineage label on pancreatic epithelial cells, permitting the evaluation of a treatment’s effects on metastatic incidence or growth. Our KPC and KPCY mice are on the C57 BL/6 strain background. Alternatively, syngeneic models provide a less labor-intensive tool for evaluating the efficacy of cancer therapies in the presence of a functional immune system. The mouse hospital employs both laparotomy and a relatively new technique of ultrasound-guided injection for orthotopic implantation of a murine PDA cell line in C57 BL/6 mice. This technique is faster, less invasive, and requires less recovery time than a traditional laparotomy. The mission of the Pancreatic Cancer Mouse Hospital of the Abramson Cancer Center is to evaluate novel PDA therapies on behalf of investigators who are at the University of Pennsylvania or are collaborating with Penn investigators. Our mouse studies are designed to mimic human clinical trials, including the use of eligibility criteria and randomized treatment assignment. Ultrasound is used for screening and to measure changes in tumor in response to therapy; serial studies permit measurement of time to diagnosis and rate of tumor progression. Additional endpoints include overall survival, serum chemistries, histology, tissue collection for pharmacodynamics studies, and immune subtyping as would be performed in a human clinical trial.

Citation Format: Cynthia Clendenin, Rina Sor, Deirdre McMenamin, Ben Z. Stanger, Gregory Beatty, Robert H. Vonderheide. A “mouse hospital” for preclinical testing of diagnostic and treatment modalities in pancreatic ductal adenocarcinoma (PDA) [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 C13.
Abstract C20: Smpd3 augments chemotherapy and thwarts PDA progression
Authors: Hendley Audrey M. , Urano Atsushi , Kerper Natanya R. , Duong Phat , Bailey Peter , Chang David K. , Biankin Andrew V. , Dawson David W. , Kim Grace , Raffai Robert L. , Hebrok Matthias
Published: March 2020

Deregulated sphingolipid metabolism alters pancreatic cancer progression; for that reason, bioactive lipid signaling molecules such as ceramide show promise as both biomarkers for disease progression and novel therapeutic targets. Intracellular ceramide levels are critical for regulating cellular senescence, apoptosis, and cell cycle arrest in response to stress stimuli such as chemotherapeutics. Our data show Sphingomyelin Phosphodiesterase 3 (Smpd3), a regulator of ceramide synthesis and exosome biogenesis, has a protumorigenic function in pancreatic ductal adenocarcinoma (PDA). Immunodeficient mice orthotopically implanted with Smpd3-deficient PDA cell lines demonstrate significantly reduced tumor burden and longer survival when compared with controls. This observation was mirrored by our KPC; Smpd3f/f mouse model, in which loss of Smpd3 expression significantly correlated with longer survival and decreased metastasis when compared to KPC; Smpd3wt/wt controls. Analysis of SMPD3 in PDA patients revealed that low SMPD3 RNA and protein expression is significantly associated with worse survival. Because chemotherapeutics have been shown to affect expression and function of SMPD3, we stratified patient cohorts into individuals who received adjuvant chemotherapy, more than 95% of which was gemcitabine, and those who did not receive adjuvant chemotherapy. We found that high SMPD3 expression in surgically resected PDA significantly correlated with longer patient survival only in patients receiving adjuvant chemotherapy, and not in the no-adjuvant-chemotherapy group. These data suggest an interaction between adjuvant chemotherapy with gemcitabine and SMPD3 expression. Furthermore, we found that gemcitabine stimulates both the enzymatic activity and expression of SMPD3 in vitro in a panel of human PDA cell lines. Our results suggest a crucial role for SMPD3 in facilitating a protumorigenic environment during PDA progression and implicate SMPD3 as a potential novel biomarker for guiding individualized chemotherapeutic regimens for PDA patients.

Citation Format: Audrey M. Hendley, Atsushi Urano, Natanya R. Kerper, Phat Duong, Peter Bailey, David K. Chang, Andrew V. Biankin, David W. Dawson, Grace Kim, Robert L. Raffai, Matthias Hebrok. Smpd3 augments chemotherapy and thwarts PDA progression [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 C20.
Abstract C29: Development of a circulating tumor DNA assay in pancreas cancer
Authors: King Dan , Olsen Mari , Fisher George , Diehn Max , Alizadeh Ash
Published: March 2020

Pancreas cancer is the third most common cause of cancer-related death, owing in part to high rates of unresectable disease at time of diagnosis and poor long-term response to chemotherapy. Biomarkers are needed to sensitively identify and monitor disease burden, and to measure response to therapy. The CA19-9 tumor marker lacks sufficient positive or negative predictive value to guide treatment decisions, and digital droplet PCR (ddPCR) assessment of circulating KRAS mutations suffers poor sensitivity on account of only assessing a single DNA locus. We hypothesize that a multitargeted circulating tumor DNA assay can outperform CA19-9 and ddPCR as biomarker for the detection and monitoring of pancreas cancer. Our lab has developed the cancer personalized profiling by deep sequencing (CAPP-Seq) method, which combines high-depth sequencing with several strategies of error-suppression to identify minute amounts of tumor DNA circulating in patients’ blood. The development of our CAPP-Seq targeted sequencing panel hinged primarily on capturing regions of the genome known to be recurrently mutated in pancreatic ductal adenocarcinoma (PDAC), based on The Cancer Genome Atlas project. These regions contain mutations in KRAS, TP53, SMAD4, and by a long-tail of mutations in many other genes for which we contributed approximately 200 kb of selector space. In addition to recurrent SNVs, we also contributed approximately 35 kb for recurrent copy number variant locations, 10 kb for recurrent noncoding variants, and 20 kb for regions with aberrant expression patterns in PDAC based on TCGA RNA-sequencing data. This purpose of this study is to employ CAPP-Seq in two pancreas cancer cohorts: patients who underwent resection at Stanford and had blood drawn before and after surgical resection (n=30), and a cohort of patients with metastatic disease who are undergoing chemotherapy with blood draws at multiple time-points (n=20). The former cohort will assess prediction of recurrence based on ctDNA level, and the latter will assess patients with early development of resistance to chemotherapy. Before assessing this ctDNA detection assay in patients with pancreas cancer, we first evaluated the CAPP-Seq approach on two healthy research subjects and achieved on average 4000x de-duplicated sequencing depth, for a theoretical limit of detection of 0.03% circulating tumor fraction. We next sequenced samples from 7 patients with resectable disease and 8 with metastatic disease, with results expected in early July.

Citation Format: Dan King, Mari Olsen, George Fisher, Max Diehn, Ash Alizadeh. Development of a circulating tumor DNA assay in pancreas 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 C29.
Abstract C33: Effects of curcumin on pancreatic ductal adenocarcinoma
Authors: Vaskas Adrianna M. , Fraietta Joseph A. , Long Kristen B.
Published: March 2020

Without an early method of diagnosis or effective treatment plan, the prognosis for pancreatic ductal adenocarcinoma (PDAC) is grim, which begs for the development of additional treatment options. The plant-derived chemical, curcumin, has recently shown some promise as a potential therapy when tested in xenograft models of PDAC, glioblastoma, lung, breast, cervical, and colon tumors and is currently being tested in early clinical trials of certain cancers. However, efficacy studies against PDAC have not included preclinical mouse models with an intact immune system. To address the potential complication of a fully functional immune system on curcumin effectiveness, we assessed the effects of curcumin on murine PDAC cell lines both in vitro and in vivo. Murine PDAC lines were previously derived from genetically engineered KrasG12D; Trp53R172H; Pdx-1 Cre (KPC) mice, which spontaneously produce metastatic PDAC that closely mimics human disease. The dose- and time-dependent toxicity of curcumin was assessed using various cell lines in vitro, and our findings support previously published results. To assess effectiveness in vivo, tumor cells were implanted subcutaneously into syngeneic, C57Bl/6J mice. Once tumors were established, curcumin (or vehicle alone) was administered via intraperitoneal (i.p.) or intratumoral injection. Treatment efficacy was assessed by measuring tumor growth and the overall survival of mice. We found that curcumin treatment had no impact on tumor growth or overall survival of immunocompetent mice. To circumvent potential solubility issues common to curcumin and illustrate the importance of the immune system in treatment resistance, we repeated our in vivo studies using curcumin encapsulated in liposomes. In addition, we used T cell-depleting antibodies for a subset of mice to mimic athymic mice used in previously published xenograft models. T-cell depletion was verified prior to tumor cell implantation by flow cytometry. Once tumors were established, liposomal curcumin or mock treatment was administered via i.p. injection. For T cell-depleted mice, we found that treatment with liposomal curcumin stalled tumor growth and increased overall survival compared to mock treated mice. For T cell-replete mice, we found that treatment with liposomal curcumin had no impact on tumor growth or overall survival compared to mock treated mice, which agrees with our findings. Taken together, our data suggest that the presence of T cells causes a difference in responsiveness to curcumin in vivo. This finding warrants additional studies in order to understand this mechanism and enhance its potential success in the clinic.

Citation Format: Adrianna M. Vaskas, Joseph A. Fraietta, Kristen B. Long. Effects of curcumin on 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 C33.
Abstract C36: A roadmap for targeting cysteine dependency in a subset of pancreatic cancer
Authors: Nwosu Zeribe C. , Ward Matthew H. , Sajjakulnukit Peter , Zhang Li , Magliano Marina Pasca di , Lyssiotis Costas A.
Published: March 2020

Cysteine is a crucial amino acid for glutathione biosynthesis, which is necessary for the maintenance of cellular antioxidant defense. Recent studies have shown that cysteine deprivation induces ferroptotic cell death in cancer cells, indicating an exploitable metabolic vulnerability for cancer therapy. However, the molecular variables that underpin cysteine dependency or can be selectively targeted to mimic cysteine deprivation are largely unknown. Here, we have studied cysteine dependency using over 20 pancreatic cancer cells (~35% of which are patient-derived), by measuring cell viability upon cystine withdrawal. In addition, we measured metabolite signatures by mass spectrometry, assessed genomic profile by bioinformatic analysis and qPCR, and also analyzed protein-level expression of cystine-glutamate antiporter SLC7A11 (xCT)—a known transporter for cystine uptake. We found that pancreatic cancer cells cluster at least into three groups, namely, cysteine-independent, moderately dependent, and highly dependent cells. The highly dependent group consistently showed low intracellular cysteine, methionine, and glutamine and a high level of intermediary metabolites of glycolytic pathway. This is accompanied by a downregulation of genes involved in apoptosis, lysosomal function, and the upregulation of cell cycle gene network as revealed by altered pathway enrichment. Further, while the cysteine-independent cells express high gene and protein levels of SLC7A11, which was further upregulated upon cysteine deprivation, the highly dependent cells expressed a very low level of SLC7A11 regardless of cysteine availability. Importantly, by analyzing the cysteine-dependent cell lines, we identified several metabolic genes that are upregulated in human pancreatic cancer and predict patient overall survival (e.g., HIF1A, LDHA, SLC16A1). In conclusion, we have uncovered differential cysteine dependency and the accompanying hallmarks in pancreatic cancer cells, thus providing impetus for targeting cysteine metabolism in a specific subset of pancreatic cancer.

Citation Format: Zeribe C. Nwosu, Matthew H. Ward, Peter Sajjakulnukit, Li Zhang, Marina Pasca di Magliano, Costas A. Lyssiotis. A roadmap for targeting cysteine dependency in a subset of 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 C36.
Abstract C40: Dissecting key biologic processes in pancreatic cancer metastasis using a genetically defined 3D organoid model
Authors: Pan Fong Cheng , Chong Angie Ai-Nok , Leach Steven D. , Chen Shuibing , Evans Todd
Published: March 2020

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest cancers, with a dismal 5-year survival rate of 6-8% due to its late detection and limited response to treatment (1,2). Multiple combinations of genetic alterations are frequently found in human PDAC, with KRAS activating mutation representing the main driver, followed by loss of tumor-suppressor genes CDKN2A, TP53, and SMAD4 as the disease progresses (3). 90% of PDAC patients die of metastatic disease (1); however, the cellular and molecular mechanisms involved in establishing the metastatic disease are understudied compared to those involved in tumor initiation. Owing to this, improved biologic understanding of PDAC metastasis remains warranted in order to develop effective therapeutic regimens for this disease. 3D organoid cultures derived from human and mouse PDAC tumors have recently become a model of choice to study PDAC tumorigenesis, gradually replacing more commonly used 2D cancer cell lines. Organoids maintain similar gene expression profiles as the in vivo situation when cultured in a 3D matrix, and genetic manipulation is feasible. We generated a panel of isogenic murine pancreatic intraepithelial neoplasia (PanIN) and PDAC organoids containing genetic mutations commonly found in human PDAC (KRAS, TP53, SMAD4, CDKN2A), either alone or in combination, using CRISPR-Cas9 technology. Since large-scale in vitro production of these PDAC organoids is achievable, the platform can be used for a multitude of downstream analyses in vitro and in vivo, such as drug screening and metastasis-related studies. The parental of these organoids is isolated from C57/Bl6 mice, which can be orthotopically transplanted into immunocompetent mice, and the resulting tumor recapitulates human and GEMM PDAC development. In the process of systematic characterization of these organoid lines, we found that organoids with more mutations exhibit higher proliferation rates in vitro and tumor formation rates in vivo. These organoids also showed genotype-dependent organotropism during metastatic colonization. We further used this unique tool to systematically address if each combination of tumor suppressor loss utilizes distinct molecular mechanisms to drive metastasis initiation and invasion. This will allow us to identify druggable pathways that could inhibit metastasis initiation/invasion and progression. Thus, these organoids provide a powerful platform for disease modeling and drug discovery both in vitro and in vivo.

Citation Format: Fong Cheng Pan, Angie Ai-Nok Chong, Steven D. Leach, Shuibing Chen, Todd Evans. Dissecting key biologic processes in pancreatic cancer metastasis using a genetically defined 3D organoid model [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 C40.
Abstract C47: Plasma ANP and soluble cell adhesion molecule X are novel risk factors for pancreatic cancer-associated thrombosis
Authors: Sano Makoto , Ijichi Hideaki , Ishigaki Kazunaga , Takahashi Ryota , Miyabayashi Koji , Tateishi Keisuke , Isayama Hiroyuki , Koike Kazuhiko
Published: March 2020

Cancer-associated thrombosis/thromboembolism (CAT) is a serious clinical complication and leads to occasional cause of death in patients with cancers, including pancreatic ductal adenocarcinoma (PDAC). However, diagnostic and inhibitory approach for CAT is still unestablished. We found that CAT with cardiomegaly and increase of plasma atrial natriuretic peptide (ANP) were frequently observed in the PDAC mice containing conditional KrasG12D mutation and knockout of TGF-β receptor type II (Tgfbr2) (PKF mice). Similar to usual thrombotic patients without cancer, high plasma level of cytokines including soluble cell adhesion molecule X was detected in the mice. Molecule-X was immunohistochemically observed in activated endothelium and thrombi. Injection of neutralized anti-molecule-X antibody reduced onset of CAT and cardiac weight in the PKF mice. Meanwhile, high plasma levels of ANP and/or molecule-X were detected in PDAC patients before and after diagnosis of CAT. Taken together, increase of ANP and/or molecule-X is a new risk factor of CAT in PDAC patients. Blocking molecule-X, at least in part, would be an inhibitory approach for CAT in PDAC.

Citation Format: Makoto Sano, Hideaki Ijichi, Kazunaga Ishigaki, Ryota Takahashi, Koji Miyabayashi, Keisuke Tateishi, Hiroyuki Isayama, Kazuhiko Koike. Plasma ANP and soluble cell adhesion molecule X are novel risk factors for pancreatic cancer-associated thrombosis [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 C47.
Abstract C49: Knockdown of FOXN2 enhances adhesion and reduces migration in pancreatic cancer cells
Authors: Santibanez Blanca , Oliveira Sabrina , Duggan Kelsie , Lu Kate , Johnson Kristen
Published: March 2020

FOXN2, a member of the forkhead domain binding protein family, was identified as a master regulator whose expression and activity are increased in the progression from pancreatic intraepithelial neoplasia (PanIN) to pancreatic ductal adenocarcinoma (PDA). Forkhead transcription factor proteins have been identified as essential components of both oncogenic and tumor suppressive pathways. Deregulation of FOX proteins has a direct role in cancer initiation, maintenance, progression, and drug resistance. In particular, other studies have linked FOXN2 expression to better outcomes in T-cell leukemia and glioblastoma multiforme. Additionally, recent studies indicate that FOXN2 impairs lung cancer cell proliferation in vivo and in vitro. Finally, recent studies in breast cancer cells indicate potential conflicting roles for the FOXN2 transcription factor in maintenance of cancer stem cell phenotypes and in migration and invasion. In the present study, we sought to understand the role of FOXN2 specifically in human pancreatic malignancy. Data from the TCGA database indicates that high levels of FOXN2 are associated with poor overall survival. While knockdown of FOXN2 does not significantly affect proliferation or colony formation of pancreatic cancer cells, we report that knockdown of FOXN2 in PANC-1 and BxPC-3 cells significantly enhances cellular adhesion. Additionally, FOXN2 knockdown reduces cellular invasion through collagen in transwell migration assays. Preliminary data suggest that FOXN2 may mediate some of its effects on adhesion and migration through regulation of Akt2 expression. Overall, our studies suggest that high FOXN2 expression and activity contribute to pancreatic malignancy. A better understanding of the regulation and function of the FOXN2 transcription factor should help us to uncover its potential as a therapeutic target, as well as a predictive marker for cancer.

Citation Format: Blanca Santibanez, Sabrina Oliveira, Kelsie Duggan, Kate Lu, Kristen Johnson. Knockdown of FOXN2 enhances adhesion and reduces migration in pancreatic cancer 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 C49.
Abstract C53: Liver X receptor ligand targets glutamine metabolism in pancreatic cancer
Authors: Srivastava Shivangi , Widmann Scott , Lin Chin-Yo
Published: March 2020

Pancreatic ductal adenocarcinoma (PDAC) is the most prevalent form of pancreatic cancer. It is predicted to become the third leading cause of cancer-related deaths by 2030. PDAC has a poor survival rate of 5 years with a 7% success rate. Current treatments include nontargeted highly toxic chemotherapeutic agents. More than 95% of PDAC patients have activating mutations of Kristen RAt Sarcoma virus (KRAS) gene, and it is known to drive metabolic reprogramming that increases cancer cell survival and resistance against the chemotherapeutic drugs. KRAS promotes noncanonical consumption of glutamine by upregulating the expression of glutaminase 1 (GLS1) enzyme. This, in turn, supports PDAC growth and survival by maintaining redox homeostasis and also by replenishing citric acid cycle intermediates. Liver X receptor beta (LXRβ), a nuclear receptor, is a ligand-dependent transcription factor that is ubiquitously expressed in all tissues. It plays an important role in maintaining cholesterol, lipid, and glucose homeostasis under normal physiologic conditions. Agonist-bound LXRβ activates the transcription of genes involved in lipogenesis, reverse cholesterol transport, and glucose metabolism. Our group has previously shown that LXRβ is expressed in PDAC tissues, and treatment with GW3965, an LXRβ agonist, reduced PDAC proliferation. However, LXRβ agonists have adverse side effects of increasing liver and circulating triglycerides. This study identified a novel ligand of LXRβ 1E5, which significantly reduced PDAC cell proliferation. 1E5 decreased the basal expression of LXRβ target genes such as sterol regulatory element-binding protein 1 (SREBP1c) and ATP binding cassette subfamily A member 1 (ABCA1). It also increased the binding of co-repressor peptides such as nuclear receptor co-repressor (NCoR) and silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) to the LXRβ ligand binding domain, whereas it decreased the binding of the co-activator peptide as demonstrated by the time-resolved fluorescence energy transfer (TR-FRET) assay, thereby inhibiting the transcriptional activity of LXRβ. Therefore, 1E5 acts as an LXRβ inverse agonist. Furthermore, the metabolomics study revealed that 1E5 disrupts glutamine metabolism in PDAC cells by downregulating the glutamine, aspartate, and alpha-ketoglutarate levels in cells. Gene expression analysis showed that it significantly downregulated GLS1 expression. These results demonstrate that the novel inverse agonist is a candidate agent in the treatment of PDAC by targeting glutamine metabolism.

Citation Format: Shivangi Srivastava, Scott Widmann, Chin-Yo Lin. Liver X receptor ligand targets glutamine metabolism in 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 C53.
Abstract C54: GATA6 level is a prognostic biomarker for pancreatic cancer in African American patients
Authors: Tang Haoyu , Sharma Anup , Nalbantoglu Ilke , Hasan Nesrin , Levchenko Andre , Ahuja Nita
Published: March 2020

Pancreatic cancer is expected to become the second leading cause of cancer-related deaths in the United States by 2030 (Weniger, Honselmann, Liss, 2018), while the limited knowledge about its pathophysiology leads to the current lack of accurate prognostic tool and satisfactory treatment. Transcription factor GATA6 is highlighted as an interesting target based on the TCGA dataset analysis of mutational burdens among 15 African American patients and 12 white patients with pancreatic cancer. A previous in vitro study revealed that GATA6 inhibited epithelial-mesenchymal transition through both direct transcriptional regulation and indirect regulation of other transcription factors (Martinelli et al., 2017). However, the correlation between GATA6 and pancreatic cancer prognosis has not been fully understood. In our study, we assessed the GATA6 protein expression levels using immunohistochemistry (IHC) of a tissue microarray from one white and four black patients. The phenotype of low GATA6 expression was only found in two of four black patients, while tumors with high GATA6 expression were found both in black and white patients. Noticeably, the patients with GATA6low phenotype demonstrated inferior survival compared to those with GATA6high phenotype, indicating GATA6 as a potential prognostic biomarker. A detailed study using more patient samples is ongoing. We also established two pancreatic cancer cell lines with specific GATA6 knockdown via the CRISPR/Cas9 method to continue investigating the role of GATA6 loss in the progress of the aggressive pancreatic cancer. Success in future work will potentially contribute to a useful prognostic tool as well as development of novel therapies for pancreatic cancer patients with GATA6low phenotype.

Citation Format: Haoyu Tang, Anup Sharma, Ilke Nalbantoglu, Nesrin Hasan, Andre Levchenko, Nita Ahuja. GATA6 level is a prognostic biomarker for pancreatic cancer in African American patients [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 C54.