bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A078: Inhibition of precancerous transformation via drug-induced p53 activation
Authors: Twardowski Jennifer J. , Heist Thomas I. , Mello Stephano S.
Published: November 2022

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer deaths in the US and has a 5-year survival rate of less than 10%. This low survival rate is largely due to low rates of early detection and the lack of treatments capable of inhibiting disease progression. Risk factors for PDAC include smoking, alcohol abuse, and pancreatitis. Pancreatic injury associated with pancreatitis is characterized by inflammation, fibrosis, and acinar cell death. Surviving acinar cells undergo acinar-to-ductal metaplasia (ADM), a regenerative process in which cells dedifferentiate, proliferate, and then redifferentiate into acinar cells. Recurrent pancreatic injury can sustain ADM and preclude redifferentiation, resulting in exocrine insufficiency and the formation of precursor lesions known as pancreatic intraepithelial neoplasia (PanIN). PanIN lesions harbor activating mutations in the MAP kinase pathway protein Kras, and can transform into PDAC after acquiring inactivating mutations in tumor suppressor p53. The lack of treatment options for pancreatitis patients reinforces the need for strategies that could resolve pancreatic damage and stop disease progression. Towards this end, we have recently shown that drug-induced activation of p53 in mouse models of pancreatitis preserves acinar cells, reduces the proliferation of PanIN lesions, and lowers levels of MAP kinase phosphorylation. We have also observed p53 activation during embryonic development of the pancreas, specifically in exocrine progenitor cells that commit to the acinar fate, suggesting a novel role of p53 in pancreatic differentiation. Based on our findings, we hypothesize that p53 activation can signal for the differentiation of acinar cells, and restrain PanIN proliferation through the suppression of MAP kinase signaling. Our studies will define the role of p53 in pancreatic differentiation and the potential of pharmacological p53 activation for the treatment for pancreatitis and prevention of PDAC.

Citation Format: Jennifer J. Twardowski, Thomas I. Heist, Stephano S. Mello. Inhibition of precancerous transformation via drug-induced p53 activation [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A078.
Abstract B008: Lipocalin-2 expression modulates ferroptosis in pancreatic ductal adenocarcinoma
Authors: Grisanti Valentina Pita , Dangel Andrew W. , Pietrzak Maciej , Hite Amy , Cruz-Monserrate Zobeida
Published: November 2022

Background: Pancreatic Ductal Adenocarcinoma (PDAC) is the third leading cause of cancer-related death in the US. Lipocalin 2 (LCN2) is upregulated in PDAC patients and promotes inflammation and tumor growth. LCN2 regulates iron levels, which are dysregulated in tumors as cancer cells uptake increased iron to support growth. High iron levels can lead to ferroptosis, an iron-catalyzed form of cell death that relies on the oxidation of poly-unsaturated fatty acids (PUFAs). Ferroptosis is usually inhibited in cancer to prevent cell death and promote tumor growth. Therefore, LCN2 expression might influence ferroptosis outcomes in PDAC. Objective: To determine whether LCN2 inhibits ferroptosis and whether modulating LCN2 levels and other targets can be leveraged as treatments to induce ferroptosis in PDAC. Methods: Lcn2 expression was deleted via CRISPR in a mouse PDAC cell line (mKPC) to generate control Lcn2+/+ and Lcn2-/- mKPC cells. Gene expression changes were analyzed with RNA sequencing. Human and mouse PDAC cells were treated with a ferroptosis inducer, LCN2 blockade, and various PUFAs. Treatment effects on cell proliferation and lipid peroxidation were measured via 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl) -2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assay and BODIPY 581/591 C11 staining respectively. Gene expression of ferroptosis markers (SLC7A11, GPX4, and SLC11A2) and LCN2 were measured via RT-qPCR. Results: Deletion of Lcn2 in mKPC cells significantly decreased the expression of genes involved in ferroptosis-inhibiting antioxidant synthesis. Ferroptosis induction upregulated Lcn2 expression in PDAC cells and decreased the viability of mKPC Lcn2-/- and human PDAC cells, but not mKPC Lcn2+/+ or human pancreatic duct epithelial cells. LCN2 blockade treatment to PDAC cells modulated the expression SLC7A11, GPX4, and SLC11A2, key enablers and inhibitors of the ferroptosis antioxidant pathway. Conclusions: Ferroptosis decreases proliferation of PDAC cells, which might be mediated by LCN2 expression. LCN2 modulation has potential to induce ferroptosis and delay PDAC growth. Future studies will determine whether a combination approach with LCN2 modulation could induce ferroptosis in PDAC. Acknowledgments: This research is supported by the OSU Pelotonia Fellowship Program and the NCI R01CA223204.

Citation Format: Valentina Pita Grisanti, Andrew W. Dangel, Maciej Pietrzak, Amy Hite, Zobeida Cruz-Monserrate. Lipocalin-2 expression modulates ferroptosis in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B008.
Abstract B027: Three-dimensional genomic analysis of human pancreatic intraepithelial neoplasia (PanIN) reveals striking multifocality and genetic heterogeneity
Authors: Braxton Alicia M. , Kiemen Ashley , Karchin Rachel , Jiao Yuchen , Wu Pei-Hsun , Hruban Ralph H , Wirtz Denis , Wood Laura D.
Published: November 2022

This abstract is being presented as a short talk in the scientific program. A full abstract is available in the Short Talks from Proffered Abstracts section (PR007) of the Conference Proceedings.

Citation Format: Alicia M. Braxton, Ashley Kiemen, Rachel Karchin, Yuchen Jiao, Pei-Hsun Wu, Ralph H Hruban, Denis Wirtz, Laura D. Wood. Three-dimensional genomic analysis of human pancreatic intraepithelial neoplasia (PanIN) reveals striking multifocality and genetic heterogeneity [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B027.
Abstract B051: Design, synthesis, and in vitro evaluation of enedione derivatives as promising selective COPZ1 inhibitor
Authors: Martins Allana Cristina F. , Barbosa Barbara M. , Badenoch Bretton , Gomes Roberto S.
Published: November 2022

Pancreatic cancer is a disease with a rising incidence and low survival rate. Anticancer drugs are effective, but are not selective, leading to serious side effects, as pain, loss of taste bud, and hair loss. The available treatments are involved in target cell proliferation, but are ineffective against nonproliferating tumor cells, which could lead to a relapse. COPZ1 and its paralogous COPZ2 are involved in intracellular trafficking and autophagy. They were identified as essential for healthy and tumor cell survival. Both COPZ1 and COPZ2 are expressed in almost the same level in normal cells. Interestingly, in tumor cells, COPZ2 is downregulated. In normal cells, the simultaneous depletion of both COPZ1 and COPZ2 leads normal cells to apoptosis, but the depletion of only one of the proteins does not affect cell cycle. This fact led us to the hypothesis that tumor cells are COPZ1 dependent, and the inhibition of this protein could lead tumor cells to apoptosis selectively once COPZ2 is naturally downregulated. Once these proteins are involved in intracellular trafficking, the inhibition of COPZ1 in COPZ2-defficient tumor cells could cause Golgi apparatus collapse, block autophagy, and induce apoptosis in both proliferating and dormant cells. This suggests that the COPZ1 knockdown may suppress tumor growth selectively, making it a promising cancer therapy target. We used molecular docking, synthesis and cell biology to prove our hypothesis. To obtain the 3D structure of COPZ2 for in silico studies purpose, a homology modeling was performed using the amino acids sequence. A set of 84 molecules were submitted to molecular docking, and 4 compounds containing the active metabolite 4-aminoantipyrine and enedione fragment were selected for synthesis and in vitro evaluation. The selection was based on the interactions between the inhibitor and the amino acids within the binding site of the enzyme. Interestingly, the selected 1-4 compounds showed cellular growth inhibition of MIA PaCa-2 and AsPC-1 cell lines, but not for normal cell line. Our new drug prototypes based on 4-aminoantipyrine and enedione moieties showed quite good anti-cancer properties, therefore deserving to be considered in further studies with the aim of understanding the role of COPZ1 in tumor development, as a target for selective treatment.

Citation Format: Allana Cristina F. Martins, Barbara M. Barbosa, Bretton Badenoch, Roberto S. Gomes. Design, synthesis, and in vitro evaluation of enedione derivatives as promising selective COPZ1 inhibitor [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B051.
Abstract B063: Differential pathway engagement and the biological consequences of KRAS variants in cancer
Authors: Avilés Yanixa Quiñones , Singh Jaffarguriqbal , Li Wenxue , Kong Yong , Liu Yansheng , Muzumdar Mandar Deepak
Published: November 2022

KRAS is a proto-oncogene found mutated in >90% of pancreatic ductal adenocarcinomas (PDAC) and encodes for a GTPase that mediates signaling transduction through the mitogen-activated protein kinase (MAPK) and PI3K/AKT pathways. Mutations in amino acids G12, G13, and Q61 prevent its inactivation by regulatory GTPase-activating proteins (GAPs), resulting in its constitutive activation. Previous work indicates that KRAS mutants possess unique biochemical differences that could result in divergent allele-specific signaling networks, underscoring unique vulnerabilities and response to treatment. Furthermore, preclinical and clinical data reveal allele-specific differences in tumor initiation capacity and patient prognosis in PDAC. Therefore, dissecting the biochemical and biological differences among KRAS variants would allow the identification of new allele-specific strategies for therapy. We hypothesize that the biochemical differences between KRAS variants result in differential signaling pathway engagement, affecting cellular behavior and tumorigenic properties. To study the biology of KRAS mutant variants in PDAC, we used CRISPR-Cas9 to generate KRAS-deficient PDAC cell lines which survived KRAS ablation through adaptive and reversible signaling rewiring. Our initial observations suggested that, at comparable expression levels, KRAS mutants diverge in their baseline signaling through the canonical MAPK and PI3K pathways. Therefore, we leveraged this unique isogenic system to uncover allele-specific differences between KRAS variants in global gene expression (by RNA-seq) and phosphoproteomic signaling networks (by data-independent acquisition mass spectroscopy; DIA-MS). We further employed a multiplexed competitive fitness approach using a sequence-based readout to assess changes in cellular fitness in response to drug perturbations (KRASi, PI3Ki, SHP2i, ERKi, RTKi and MEKi). Our findings suggest that KRAS mutants cluster into groups that diverge in downstream pathway engagement and gene expression, leading to cluster-specific differences in drug sensitivity. Our findings suggest that elucidating the signaling differences between KRAS alleles and their biological functions could translate to novel therapeutic strategies in PDAC and other KRAS mutant cancers.

Citation Format: Yanixa Quiñones Avilés, Jaffarguriqbal Singh, Wenxue Li, Yong Kong, Yansheng Liu, Mandar Deepak Muzumdar. Differential pathway engagement and the biological consequences of KRAS variants in cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B063.
Abstract B067: Genetic and pharmacological inhibition of phospholipase D1 reduces pancreatic carcinogenesis in mice
Authors: Addassi Hala A. , Mackenzie Gerardo G.
Published: November 2022

Pancreatic ductal adenocarcinoma (PDA) is a leading cause of cancer-related death in the United States and is characterized by its sudden manifestation, poor prognosis, high incidence of metastasis, and aggressive tumor growth. Phospholipase D1 (PLD1) is a lipid-signaling enzyme that plays a role in signaling pathways that lead to cell proliferation, survival/apoptosis as well as downstream oncogenic transformation involved in cancer progression. PLD1 activity has been shown to promote tumor progression in other cancer types, however, the role and mechanisms of PLD1 in pancreatic cancer is not yet understood. The objective of this study is to determine the role of PLD1 regulation in pancreatic carcinogenesis through genetic-ablation and pharmacological inhibition of PLD1. In this study, we crossed the LSL-KrasG12D/+;Ptf1Cre/+ (KC) mice into PLD1 knockout (Pld1-/-) mice to generate KC; Pld1-/- mice in the C57BL/6 background to examine whether PLD1 is required for pancreatic tumorigenesis. Cohorts of male and female KC and KC; Pld1-/- mice, (8-12 mice per group), were euthanized at 4 and 8 months old and the pancreas was carefully resected. At 8 months of age, there was a significant difference (p<0.05) in the pancreas weight at sacrifice between the KC mice and the KC; Pld1-/- mice in a sex-dependent manner. This was due, in part, by a reduction in tumor proliferation as determined by Ki67 expression. To assess whether pharmacological inhibition of PLD could prevent pancreatic carcinogenesis in KC mice, cohorts of 9-12 male 7-month-old KC mice received daily intraperitoneal injections of a small molecule inhibitor of PLD (FIPI) at a dosage of 3 mg/kg of body weight for a duration of 5 weeks. The mice were euthanized at 8.5 months of age and the pancreas was carefully resected. Histological analysis indicated that FIPI-treated KC mice displayed less acinar cell loss compared to vehicle-treated KC controls. Moreover, treatment with FIPI significantly reduced cell proliferation (p<0.01) in KC mice in comparison to vehicle-treated KC mice. In summary, these results indicate that PLD1 plays a critical role in pancreatic carcinogenesis and may represent a novel therapeutic target. Additional studies are underway to explore the cellular mechanisms of how PLD1 inhibition modulates pancreatic carcinogenesis.

Citation Format: Hala A. Addassi, Gerardo G. Mackenzie. Genetic and pharmacological inhibition of phospholipase D1 reduces pancreatic carcinogenesis in mice [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B067.
Abstract B070: Deletion of NEMO inhibits PanIN development but accelerates PanIN progression towards PDAC
Authors: Tsesmelis Miltiadis , Gerstenlauer Melanie , Manfras Uta , Barth Thomas F.E. , Maier Harald Jakob , Chan Lap Kwan , Wirth Thomas
Published: November 2022

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest types of cancer with a 5-year survival rate of less than 10%. Importantly, the canonical NF-κB pathway, which regulates critical cellular functions including inflammation, is active in the majority of PDAC cases as well as in pancreatic intraepithelial neoplasias (PanINs). Our study investigated the role of NF-κB signaling in the development and progression of PanINs and PDAC by deleting NF-κB essential modulator (NEMO), an essential protein for the activation of the NF-κB pathway. We used genetically-modified mice with pancreas-specific expression of oncogenic KRAS (KC mouse model). To blunt the canonical NF-κB pathway, KC mice were crossed to NEMO-floxed mice, allowing pancreas-specific deletion of NEMO (KNeC mouse model). The mice were injected with cerulein to promote the development of pancreatitis and accelerate the development of PDAC. Analysis of the pancreata at the time point of 8 weeks revealed that NEMO deletion reduced the infiltration of immune cells and the collagen deposition in the pancreas. However, no significant difference in the number of PanINs between the KC and KNeC mice was observed. In contrast, analysis at the time point of 10 months demonstrated that NEMO deletion drastically reduced the total number of PanINs and the field covered by desmoplasia. In addition, KNeC pancreata exhibited reduced inflammation compared to KC pancreata. Strikingly, however, NEMO deletion accelerated the progression of low-grade to high-grade PanINs and eventually to PDAC and reduced the lifespan of the mice. Mechanistically, NEMO deletion blocked the oncogene-induced senescence (OIS) that is active in low-grade PanINs. RNA-seq analysis revealed that inhibition of OIS resulted in reduced expression of the senescence-associated secretory phenotype (SASP). Finally, NEMO deletion increased the proliferation rate and the accumulation of DNA damage in precancerous lesion cells, supporting their progression to high-grade PanINs. Collectively, our study gives a mechanistic insight of the role of NF-κB in the development and progression of precancerous lesions. It underscores that NEMO exerts oncogene properties by supporting the development of new low-grade PanINs, but at the same time, it exerts tumor-suppressor properties by maintaining OIS in PanINs.

Citation Format: Miltiadis Tsesmelis, Melanie Gerstenlauer, Uta Manfras, Thomas F.E. Barth, Harald Jakob Maier, Lap Kwan Chan, Thomas Wirth. Deletion of NEMO inhibits PanIN development but accelerates PanIN progression towards PDAC [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B070.
Abstract B078: PP2A activation drives alternative EGFR activation in PDAC
Authors: Pfeffer Claire M. , Clifford Sydney J. , Hoffman Elizabeth G. , Mall Gagan K. , Baral Garima , Allen-Petersen Brittany L.
Published: November 2022

Pancreatic ductal adenocarcinoma (PDAC) stands to become the 2nd most deadly cancer by 2030. Over 90% of PDAC patients have oncogenic KRAS mutations with the most prevalent being KRASG12D which have proven difficult to therapeutically target. Several studies have implicated EGFR signaling as critical for PDAC tumorigenesis in KRAS mutant tumors. Consistent with these findings, the first FDA-approved targeted therapeutic for PDAC was the EGFR inhibitor, Erlotinib. However, single agent use of Erlotinib has shown minimal efficacy in the clinic suggesting that this signaling is complex and needs further interrogation. Studies have shown the serine/threonine phosphatase, Protein Phosphatase 2A (PP2A), negatively regulates several downstream targets of EGFR and KRAS. Our previous studies using small molecule activators of PP2A demonstrate a heterogeneous response to PP2A activation, with some PDAC cell lines downregulating oncogenic signals and others maintaining the oncogenic signaling. Using pharmacological activation of PP2A, as well as overexpression and knockdown studies, we have identified a novel signaling cascade in which PP2A activation leads to increased expression and secretion of EGFR ligands and EGFR activation in a subset of PDAC cell lines. Given this unique feedback mechanism, we combined EGFR inhibitors with PP2A activation and found that the combination killed more cells than either agent alone. Together, our studies identify a novel role for PP2A in regulating EGFR signaling and support the combined use of EGFR inhibitors and PP2A activators to increase efficacy of both agents.

Citation Format: Claire M. Pfeffer, Sydney J. Clifford, Elizabeth G. Hoffman, Gagan K. Mall, Garima Baral, Brittany L. Allen-Petersen. PP2A activation drives alternative EGFR activation in PDAC [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B078.
Abstract C023: A microbiome-produced metabolite drives immunostimulatory macrophages and boosts response to immune checkpoint inhibitors in pancreatic cancer
Authors: Mirji Gauri , Worth Alison , Bhat Sajad , Sayed Mohamed , Kannan Toshitha , Goldman Aaron , Tang Hsin-Yao , Liu Qin , Auslander Noam , Dang Chi , Abdel-Mohsen Mohamed , Kossenkov Andrew , Stanger Ben , Shinde Rahul
Published: November 2022

The composition of the gut microbiome controls innate and adaptive immunity and has emerged as a key regulator of tumor growth and the success of immune checkpoint blockade (ICB) therapy. However, the underlying mechanisms remain unclear. Pancreatic ductal adenocarcinoma (PDAC) tends to be refractory to therapy, including ICB. We found that the gut microbe-derived metabolite trimethylamine N-oxide (TMAO) enhances anti-tumor immunity to PDAC. Delivery of TMAO given intraperitoneally or via dietary choline supplement to PDAC-bearing mice reduces tumor growth and is associated with an immunostimulatory tumor-associated macrophage (TAM) phenotype and activated effector T cell response in the tumor microenvironment. Mechanistically, TMAO signals through potentiating type-I interferon (IFN) pathway and confers anti-tumor effects in a type-I IFN dependent manner. Notably, delivering TMAO-primed macrophages alone produced similar anti-tumor effects. Combining TMAO with ICB (anti-PD1 and/or anti-Tim3) significantly reduced tumor burden and improved survival beyond TMAO or ICB alone. Finally, the levels of trimethylamine (TMA)-producing bacteria and of CutC gene expression correlate with improved survivorship and response to anti-PD1 in cancer patients. Together, our study identifies the gut microbial metabolite TMAO as an important driver of anti-tumor immunity and lays the groundwork for new therapeutic strategies.

Citation Format: Gauri Mirji, Alison Worth, Sajad Bhat, Mohamed Sayed, Toshitha Kannan, Aaron Goldman, Hsin-Yao Tang, Qin Liu, Noam Auslander, Chi Dang, Mohamed Abdel-Mohsen, Andrew Kossenkov, Ben Stanger, Rahul Shinde. A microbiome-produced metabolite drives immunostimulatory macrophages and boosts response to immune checkpoint inhibitors in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C023.
Abstract C035: Biotherapeutic strategies targeting the CXCR2 axis for depletion of myeloid-derived suppressor cells in pancreatic ductal adenocarcinoma
Authors: Christopher Ben N. , Robinson Reeder , Reyes Leticia , Golick Lena , Basar Ashton , Dolloff Nathan
Published: November 2022

Pancreatic Ductal Adenocarcinoma (PDAC) has a 5-year survival rate of only 10%, and limited treatment options exist. Immune checkpoint inhibitors are effective in a variety of cancer types; however, the complex immunosuppressive tumor microenvironment (TME) of PDAC is a significant barrier to immunotherapy. Myeloid-derived suppressor cells (MDSCs) are abundant in PDAC tumors from humans and mouse models. MDSCs suppress effector T cell function, leading us to hypothesize that targeting tumor MDSCs would be an effective therapeutic strategy for PDAC and enhance the efficacy of T cell-based immunotherapy. Our preliminary data and the work from others shows that CXCR2 ligands such as CXCL8/IL-8, CXCL5/ENA78, and CXCL1/GROα are the most abundant soluble factors secreted by PDAC cells. CXCR2 ligands are critical for the homing of myeloid cells to sites of injury in cutaneous wound healing, suggesting that dysregulated secretion of CXCR2 chemokines in PDAC may mimic a wound healing response that attracts myeloid cells and promotes the expansion of MDSCs and an immunosuppressive TME. To test this hypothesis, we have designed multiple biotherapeutic molecules that exploit CXCL5/ENA78 and CXCL1/GROa to target and eliminate MDSCs from PDAC tumors. Specifically, we have generated Pseudomonas aeruginosa exotoxin (ExoA) and IgG-Fc fusion proteins that will be used to deliver cytotoxic payloads to MDSCs. A variety of CXCR2 knockout and knock-in models will be used to demonstrate CXCR2 dependence and elimination of MDSCs in vitro. In vivo, we are utilizing the KPC (LSL-KrasG12D/+;LSL-Trp53R172H/+;Pdx-1-Cre) mouse model of PDAC, which we've shown in preliminary studies to, like human PDAC, support an abundance of MDSCs in tumors as well as secondary lymphoid organs such as the spleen. We anticipate that this study will demonstrate the therapeutic potential and actionability of targeting MDSCs and will provide novel biotherapeutic drug candidates that will ultimately improve immunotherapy outcomes in patients with PDAC.

Citation Format: Ben N. Christopher, Reeder Robinson, Leticia Reyes, Lena Golick, Ashton Basar, Nathan Dolloff. Biotherapeutic strategies targeting the CXCR2 axis for depletion of myeloid-derived suppressor cells in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C035.
Abstract C039: An EGFR-activated subset of myofibroblastic cancer-associated fibroblasts supports local metastatic dissemination in pancreatic ductal adenocarcinoma
Authors: Mucciolo Gianluca , Henríquez Joaquín Araos , Teles Sara Pinto , Manansala Judhell , Li Wenlong , Lloyd Eloise G. , Cheng Priscilla , Biffi Giulia
Published: November 2022

Pancreatic ductal adenocarcinoma (PDA) has a dismal prognosis and new therapies are needed. Cancer-associated fibroblasts (CAFs) can promote PDA progression and are recognized promising therapeutic targets. However, the ongoing characterization of PDA CAF heterogeneity and plasticity and the identification of potential tumor-restraining CAF populations have highlighted the need to further dissect the diverse biology of PDA CAFs to develop effective combination therapies. Using pancreatic organoid/fibroblast co-cultures and organoid-derived transplantation mouse models of PDA, we mechanistically investigated the signaling cascade downstream TGF-beta activation, which is a main driver of myofibroblastic CAF (myCAF) formation. We find that the EGFR/ERBB2 pathway is activated by TGF-beta in a subset of myCAFs, in both murine and human PDA, via amphiregulin induction and autocrine signaling. ERBB activation is important for the maintenance of this myCAF subset, with genetic and pharmacological inhibition of this pathway differentially affecting PDA CAF composition both in culture and mouse models. Importantly, analysis of lung cancer and breast cancer patient samples suggests that our observations in PDA are also relevant to these malignancies. Finally, we reveal a role of this EGFR-activated myCAF subset in promoting local metastatic dissemination in PDA and indicate new potential combination strategies. Our study highlights the need to better dissect PDA CAF heterogeneity also in populations typically considered to be tumor-restraining, in order to develop effective combination strategies for future clinical intervention. Our work also reveals how cancer-targeting therapies can directly affect the surrounding microenvironment with potential clinical implications for various malignancies.

Citation Format: Gianluca Mucciolo, Joaquín Araos Henríquez, Sara Pinto Teles, Judhell Manansala, Wenlong Li, Eloise G. Lloyd, Priscilla Cheng, Giulia Biffi. An EGFR-activated subset of myofibroblastic cancer-associated fibroblasts supports local metastatic dissemination in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C039.
Abstract C042: Deletion of Gα13 promotes inflammation in the KPC mouse model of pancreatic cancer
Authors: Shields Mario A. , Metropulos Anastasia E. , Spaulding Christina , Pham Thao ND , Munshi Hidayatullah G.
Published: November 2022

G protein-coupled receptor (GPCR) signaling regulates many aspects of tumor biology, including inflammation, angiogenesis, and metastasis. However, the tumor-specific functions of G proteins, immediate downstream signaling partners of GPCRs, are not well understood. Counter to previous reports in epithelial cancer cell lines, we recently showed that Gα13, a member of the G12 family of heterotrimeric G proteins, is a tumor suppressor in the genetically engineered KPC (Pdx1-Cre; KrasG12D/+; Tp53R172H/+) mouse model of pancreas cancer (Shields et al., Cell Rep, 2022). Mechanistically, we found that Gα13 loss increases mTOR signaling in mouse and human pancreas tumors and that Gα13-deficient tumors are susceptible to rapamycin. We now show that Gα13 loss in the KPC mouse model is also associated with increased expression of inflammatory cytokines. Moreover, loss of Gα13 also promotes NF-κB signaling and inflammatory cytokines expression in cerulein-driven pancreatitis. Consistently, we find that loss of Gα13 increases the recruitment of macrophages and promotes acinar-ductal metaplasia in cerulein-driven pancreatitis. In our ongoing studies, we are evaluating the role of mTOR signaling in mediating the increased inflammation seen following the loss of Gα13 in our mouse models. Together, our studies show that the tumor-suppressive function of Gα13 is related to the regulation of mTOR signaling and inflammation in pancreas cancer.

Citation Format: Mario A. Shields, Anastasia E. Metropulos, Christina Spaulding, Thao ND Pham, Hidayatullah G. Munshi. Deletion of Gα13 promotes inflammation in the KPC mouse model of pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C042.
Abstract C078: Mesothelial cell-derived antigen-presenting cancer-associated fibroblasts induce expansion of regulatory T cells in pancreatic cancer
Authors: Huang Huocong , Wang Zhaoning , Zhang Yuqing , Pradhan Rachana N. , Ganguly Debolina , Chandra Raghav , Murimwa Gilbert , Wright Steven , Gu Xiaowu , Maddipati Ravikanth , Müller Sören , Turley Shannon J. , Brekken Rolf A.
Published: November 2022

Recent studies have identified a unique cancer-associated fibroblast (CAF) population termed antigen-presenting CAFs (apCAFs), characterized by the expression of major histocompatibility complex class II molecules, suggesting a function in regulating tumor immunity. Here, by integrating multiple single-cell RNA-sequencing studies and performing robust lineage-tracing assays, we find that apCAFs are derived from mesothelial cells. During pancreatic cancer progression, mesothelial cells form apCAFs by downregulating mesothelial features and gaining fibroblastic features, a process induced by interleukin-1 and transforming growth factor β. apCAFs directly ligate and induce naive CD4+ T cells into regulatory T cells (Tregs) in an antigen-specific manner. Moreover, treatment with an antibody targeting the mesothelial cell marker mesothelin can effectively inhibit mesothelial cell to apCAF transition and Treg formation induced by apCAFs. Taken together, our study elucidates how mesothelial cells may contribute to immune evasion in pancreatic cancer and provides insight on strategies to enhance cancer immune therapy.

Citation Format: Huocong Huang, Zhaoning Wang, Yuqing Zhang, Rachana N. Pradhan, Debolina Ganguly, Raghav Chandra, Gilbert Murimwa, Steven Wright, Xiaowu Gu, Ravikanth Maddipati, Sören Müller, Shannon J. Turley, Rolf A. Brekken. Mesothelial cell-derived antigen-presenting cancer-associated fibroblasts induce expansion of regulatory T cells in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C078.
Abstract C079: Aberrantly exposed phosphatidylserine as a drug delivery target in pancreatic cancer
Authors: Phinney Natalie Z. , Huang Xianming , Brekken Rolf
Published: November 2022

Pancreatic ductal adenocarcinoma (PDA) has risen to become the 3rd leading cause of cancer related deaths in the United States with a 5-year survival rate of 11% and a median survival of just 4-6 months. PDA is notoriously chemoresistant and has shown little to no sensitivity to the current immune checkpoint blockade therapy. A novel marker for the tumor microenvironment that has emerged is phosphatidylserine, initially characterized as a selective marker of tumor vasculature. Phosphatidylserine (PS) is a phospholipid exposed on the outer leaflet of the plasma membrane of tumor associated endothelial cells, apoptotic tumor cells, and some viable tumor cells, where it functions to suppress the immune response. Exposed PS drives immunosuppression by binding to PS receptors expressed on tumor-infiltrating macrophages and dendritic cells. To this point, PS has been targeted with antibodies, such as Bavituximab, that have shown excellent specificity for tumor vasculature and an immune stimulatory environment evidence by polarization of macrophages to a pro-inflammatory M1-like phenotype, a reduction in myeloid-derived suppressor cells, enhanced maturation of dendritic cells and increased primed T cell activity. We have advanced this concept by developing the next generation of PS targeting agent, a fusion protein (betabody) that exploits the PS-binding domain of β2-glycoprotein 1 (β2GP1), an abundant serum protein that binds PS. Betabodies were constructed by fusing domain V of β2GP1 to the Fc of an IgG2a. Betabodies are smaller than full length antibodies (~85 kDa vs 150 kDa), have good affinity for PS (~1 nM) and bind directly to PS. We have demonstrated that betabodies bind specifically to externalized PS through ELISA, ICC and flow cytometry. We established that betabodies localize robustly and specifically to the tumor microenvironment through in vivo localization experiments in tumor-bearing C57Bl/6 mice. Further studies will exploit the specificity of betabodies to deliver novel microtubule-disrupting agents to exposed PS in the microenvironment of PDA. Due to the fact that betabodies are internalized inefficiently, therapeutic payloads will be linked to betabodies via enzyme cleavable linkers. This first-in-class tumor targeting therapeutic has potential to provide efficacy in therapy-resistant pancreatic tumors.

Citation Format: Natalie Z. Phinney, Xianming Huang, Rolf Brekken. Aberrantly exposed phosphatidylserine as a drug delivery target in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C079.
Abstract IA019: Stromal-epithelial co-evolution and complicity in pancreas cancer
Authors: Hingorani Sunil R.
Published: November 2022

The robust desmoplasia of PDA is its distinguishing feature and non-malignant components constitute the bulk of the tumor mass. This stromal reaction includes myofibroblasts, inflammatory fibroblasts, endothelial cells, pericytes, and various immune-cell subsets, all embedded within a dense and complex extracellular matrix (ECM). Dominated by non-malignant cells, the mutated epithelium must therefore combat, cooperate with, or coopt the surrounding cells and signaling processes in its microenvironment. It is proposed that an invasive PDA represents the coordinated evolution of malignant and non-malignant cells and mechanisms that subvert and repurpose the dictums of normal tissue composition, architecture, and physiology to foster tumorigenesis. The detailed kinetics and stepwise construction of the pancreas cancer neo-organ suggest that it is governed by a discrete set of organizing rules and principles – and repeated attempts to target its specific components reveal self-regulating mechanisms of resistance. Indeed, many of these cells arise and operate at the behest of oncogenic KRAS, the signature genetic mutation in PDA. These cells, in turn, support and shape the evolving malignancy. It is frequently debated in pancreas and other cancers whether the stroma is “good” or “bad”, tumor-constraining or tumor-promoting. However, because the stroma is neither static nor monolithic, the question is misguided. The stroma is more nuanced: some elements overtly accelerate, and others attenuate, disease progression but most of the cells and processes found in an evolving pancreas cancer are adaptive at some point during its development. In the end, these elements collectively conspire to create a drug- and immune-privileged sanctuary for PDA progression. To fully overcome the extraordinary resistance of this formidable cancer will require parsing the myriad interactions and interdependencies among the various stromal elements and the epithelial PDA cell. Understanding how to combine strategies against these distinct components and processes – which ones to target, in what order and for how long – will be critical, and perhaps necessary, for success and to avoid making matters worse.

Citation Format: Sunil R. Hingorani. Stromal-epithelial co-evolution and complicity in pancreas cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr IA019.
Abstract PR018: Hypoxia synergizes with IL1 to promote an inflammatory fibroblast state in the pancreatic tumor microenvironment
Authors: Schwoerer Simon , Ros Manon , Tsanov Kaloyan , Cimino Francesco , Lowe Scott , Carmona-Fontaine Carlos , Thompson Craig
Published: November 2022

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a prominent desmoplastic response created by cancer-associated fibroblasts (CAFs) that can acquire both tumor-promoting and -restraining functions. Recently, transcriptionally distinct subpopulations of CAFs have been identified in PDAC including tumor-restraining myofibroblastic CAFs (myCAFs) producing extracellular matrix and tumor-promoting inflammatory CAFs (iCAFs) secreting cytokines. While CAF heterogeneity can be driven in part by growth factor and cytokine gradients, other factors involved in shaping the CAF state in PDAC are largely unknown. Identifying and targeting such factors may help to drive CAFs from tumor-promoting into tumor-suppressive states. Hypoxia is a major environmental factor in the PDAC tumor microenvironment but its role in CAF plasticity is unknown. In this study, we use KPC organoid orthotopic transplantation and co-culture models to investigate the role of hypoxia in regulating the CAF state and functions. We find that iCAFs display a hypoxic gene expression and biochemical profile in vivo and are enriched in hypoxic regions of PDAC tumors. Hypoxia leads to acquisition of an inflammatory gene expression signature in fibroblasts and synergizes with cancer cell-derived IL1 to promote an iCAF phenotype in a HIF-1α dependent fashion. Furthermore, we show in PDAC organoid co-culture models that HIF-1α stabilization is sufficient to induce an iCAF phenotype in pancreatic stellate cells and to promote PDAC tumor growth in vivo in the absence of hypoxia. These data indicate

Citation Format: Simon Schwoerer, Manon Ros, Kaloyan Tsanov, Francesco Cimino, Scott Lowe, Carlos Carmona-Fontaine, Craig Thompson. Hypoxia synergizes with IL1 to promote an inflammatory fibroblast state in the pancreatic tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr PR018.
Abstract PR022: IL-17/IL-17RA signaling in the pancreatic epithelium upregulates CXCL5 and B7-H4 to promote tumorigenesis
Authors: Pando Lourdes Susana Castro , McAllister Florencia , Roux Olivereen Le , Riquelme Erick , Li Le
Published: November 2022

Pancreatic ductal adenocarcinoma (PDAC) is predicted to become the second leading cause of cancer-related mortality. PDAC characterized by its highly immunosuppressive fibro-cellular tumor microenvironment (TME), which forms early during pancreatic tumorigenesis. Our group has shown that IL-17 is required for the initiation and progression of pancreatic cancer, but we have not defined the cellular compartment, mechanisms and signaling involved in IL-17-mediated tumor promotion. We hypothesize that pancreatic epithelial IL-17/IL-17RA signaling, rather than hematopoietic signaling, is required for early pancreatic tumorigenesis through modulation of an immunosuppressive program. To test our hypothesis, we generated mice with Kras activated and IL-17RA deleted specifically from the pancreatic epithelial compartment (KC; IL-17rafl/fl). Also, we transplanted IL-17RA deficient (IL17ra-/-) bone marrow cells into KC mice so IL-17RA is deleted specifically from hematopoietic cells. We found that the deletion of IL-17RA in the epithelial compartment delays the formation of premalignant lesions, conversely the deletion of IL-17RA in the hematopoietic compartment shows no change in the development of pancreatic tumorigenesis. Suggesting that the IL-17/IL-17RA signaling is through the pancreatic epithelium. Moreover, IL-17RA deletion in the oncogenic epithelium causes an increasing of CD3+ and CD8+ while decreasing F4/80+ Cells in TME. Furthermore, Cxcl5 and B7-H4 Aare less expressed in premalignant lesion of KC; IL-17RAf/f mice. Cxcl5 is a cytokine involve in neutrophil recruitment while B7-H4 can inhibit T cell response. By in vitro studies we have found that IL-17 stabilize the mRNA of CXCL5. Further studies are needed to understand how IL-17 mediates signaling in the pancreatic oncogenic epithelium trough Cxcl5.

Citation Format: Lourdes Susana Castro Pando, Florencia McAllister, Olivereen Le Roux, Erick Riquelme, Le Li. IL-17/IL-17RA signaling in the pancreatic epithelium upregulates CXCL5 and B7-H4 to promote tumorigenesis [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr PR022.
Tumor-Suppressive and Immune-Stimulating Roles of Cholesterol 25-hydroxylase in Pancreatic Cancer Cells
Authors: McBrearty Noreen , Cho Christina , Chen Jinyun , Zahedi Farima , Peck Amy R. , Radaelli Enrico , Assenmacher Charles-Antoine , Pavlak Clarice , Devine Anne , Yu Pengfei , Lu Zhen , Zhang Hongru , Li Jinyang , Pitarresi Jason R. , Astsaturov Igor , Cukierman Edna , Rustgi Anil K. , Stanger Ben Z. , Rui Hallgeir , Fuchs Serge Y.
Published: November 2022

Cholesterol dependence is an essential characteristic of pancreatic ductal adenocarcinoma (PDAC). Cholesterol 25-hydroxylase (CH25H) catalyzes monooxygenation of cholesterol into 25-hydroxycholesterol, which is implicated in inhibiting cholesterol biosynthesis and in cholesterol depletion. Here, we show that, within PDAC cells, accumulation of cholesterol was facilitated by the loss of CH25H. Methylation of the CH25H gene and decreased levels of CH25H expression occurred in human pancreatic cancers and was associated with poor prognosis. Knockout of Ch25h in mice accelerated progression of Kras-driven pancreatic intraepithelial neoplasia. Conversely, restoration of CH25H expression in human and mouse PDAC cells decreased their viability under conditions of cholesterol deficit, and decelerated tumor growth in immune competent hosts. Mechanistically, the loss of CH25H promoted autophagy resulting in downregulation of MHC-I and decreased CD8+ T-cell tumor infiltration. Re-expression of CH25H in PDAC cells combined with immune checkpoint inhibitors notably inhibited tumor growth. We discuss additional benefits that PDAC cells might gain from inactivation of CH25H and the potential translational importance of these findings for therapeutic approaches to PDAC.

Implications:

Loss of CH25H by pancreatic cancer cells may stimulate tumor progression and interfere with immunotherapies.
Inactivation ofNotch4Attenuated Pancreatic Tumorigenesis in Mice
Authors: Saeki Kiyoshi , Qiu Wanglong , Friedman Richard A. , Pan Samuel , Lu Jordan , Ichimiya Shu , Chio Iok In Christine , Shawber Carrie J. , Kitajewski Jan , Hu Jianhua , Su Gloria H.
Published: November 2022

Expression of the Notch family of receptors is often upregulated in pancreatic ductal adenocarcinoma (PDAC). In this study, we focused on Notch4, which had not been investigated in PDAC.

We generated KC (LSL-KrasG12D;p48-Cre), N4−/−KC (Notch4−/−;LSL-KrasG12D;p48-Cre), PKC (p16fl/fl;LSL-KrasG12D;p48-Cre), and N4−/−PKC (Notch4−/−; p16fl/fl;LSL-KrasG12D;p48-Cre) genetically engineered mouse models (GEMM). We performed caerulein treatment in both KC and N4−/−KC mice, and the development of acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) lesions were significantly diminished in the N4−/−KC than in the KC GEMM (P = 0.01). This in vivo result was validated by in vitro ADM induction of the explant cultures of pancreatic acinar cells from the N4−/−KC and KC mice (P < 0.001), confirming that Notch4 is an important contributor to early pancreatic tumorigenesis.

To evaluate the role of Notch4 in the later stage of pancreatic tumorigenesis, we compared the PKC and N4−/−PKC mice. The N4−/−PKC mice had better overall survival (P = 0.012) and significantly reduced tumor burden (PanIN: P = 0.018 at 2 months, PDAC: P = 0.039 at 5 months) compared with the PKC GEMM. RNA-sequencing analysis of pancreatic tumor cell lines derived from the PKC and N4−/−PKC GEMMs revealed that 408 genes were differentially expressed (FDR < 0.05) and Pcsk5 is a potential downstream effector of the Notch4 signaling pathway (P < 0.001). Low expression of Pcsk5 positively correlates with good survival in patients with PDAC (P = 0.028).

We have identified a novel role for Notch4 signaling with tumor-promoting function in pancreatic tumorigenesis. Our study also uncovered a novel association between Pcsk5 and Notch4 signaling in PDAC.

Significance:

We demonstrated that global inactivation of Notch4 significantly improved the survival of an aggressive mouse model for PDAC and provided preclinical evidence that Notch4 and Pcsk5 are novel targets for PDAC therapies.
Faster Macular Vessel Density Loss in More Advanced Primary Open Angle Glaucoma Eyes
Authors: Shang Xiao , Wang Xiaoyan , Zhou Kun , Pan Xiafei , Huang Qiangjie , Chu Xizhong , Hu Chengju , Xu Xiang , Liang Yuanbo
Published: November 2022

Purpose: The aim of the study was to characterize and compare the longitudinal changes of macular vessel density (VD) in primary open angle glaucoma (POAG) eyes across different disease stages. Methods: This is a sub-analysis of a prospective cohort study. A total of 103 eyes (53 eyes in the mild stage, 50 eyes in the moderate-to-advanced stage) of 75 POAG patients followed for more than 1 year with at least 2 qualified optical coherence tomography (OCT) angiography (OCTA) images were included. The rates of macular VD change were determined by linear regression and compared using the generalized linear mixed models between groups. Mixed effect models were used to evaluate the demographic and ocular parameters associated with the VD loss rate. Results: With a mean follow-up time of 2.36 years, the rates of macular VD change were significantly different from zero in both groups. The rates of macular VD loss were significantly faster in moderate-to-advanced-stage group than in mild-stage group in whole image (−2.46%/year vs. −1.47%/year, p = 0.002);, superior hemifield (−2.42%/year vs. −1.30%/year, p = 0.001); parafovea (−2.35%/year vs. −1.26, p = 0.001); superior (−2.20%/year vs. −1.01%/year, p = 0.002), nasal (−2.41%/year vs. −1.04%/year, p = 0.001), inferior (−2.46%/year vs. −1.43%/year, p = 0.018), and temporal sectors (−2.32%/year vs. −1.58%/year, p = 0.012). Baseline mean deviation and OCT parameters were associated with the rates of macular VD loss. Conclusions: OCTA measurements could detect vascular deterioration over time in POAG eyes at different stages. The rates of macular VD loss were significantly faster in more advanced POAG eyes.