Animal Models Of Pancreatic Cancer Research Articles

Abstract B080: A porcine model of pancreatic ductal adenocarcinoma for human scale translational cancer research

Abstract Pancreatic ductal adenocarcinoma (PDAC) remains a highly fatal form of cancer, requiring urgent advancements in diagnostic and therapeutic strategies. Although PDAC mouse models have been crucial in advancing our comprehension of the disease, they present some limitations in replicating key human PDAC aspects. In this study, we present the development of the first large animal model of pancreatic cancer via Cre activatable mutations in the endogenous KRAS and TP53 genes 1,2. In order to activate these mutations in the pancreas, two Cre driver pig lines expressing Cre recombinase from PTF1A 3 and PDX1 were created. Crossing both Cre lines with pigs carrying latent KRAS G12D and TP53 R167H alleles produced double (KC) and triple (KPC) genetically modified animals. Pathological analyses revealed the presence of inter- and intralobular fibrosis with multifocal acinar-to-ductal metaplasia (ADM), some low-grade PanINs, dysplasia, inflammation and duct obstruction in most of the KPC pigs between 3 to 6 months of age. Interestingly, the majority of these pigs already exhibited local metastasis in the lymph nodes, suggesting that the metastatic potential is established early in the tumorigenic process. Age-matched KC pigs exhibited mainly ADM with dysplasia. Flow cytometry and RNA expression analyses of the established pancreatic tumour primary cells revealed a pronounced epithelial-to-mesenchymal transition (EMT). Moreover, both bulk tumour samples and primary tumour cells showed high expression of the pancreatic cancer stem cell marker CD44, with differential expression of its isoforms, including the major isoform and variants 6 and 9. In addition, histological and molecular analyses revealed notable similarities between pig and human PDAC, including molecular subtypes, neuronal invasion and loss of acinar identity. These findings highlight the unique advantage of the pig PDAC model, that allows longitudinal and multi-regional tumour sampling in the absence of any therapeutic interventions. This makes it a valuable tool for developing new diagnostic and therapeutic approaches that can greatly improve patient outcomes in the long run.

Using microRNAs Networks to Understand Pancreatic Cancer-A Literature Review.

Pancreatic cancer is a severe disease, challenging to diagnose and treat, and thereby characterized by a poor prognosis and a high mortality rate. Pancreatic ductal adenocarcinoma (PDAC) represents approximately 90% of pancreatic cancer cases, while other cases include neuroendocrine carcinoma. Despite the growing knowledge of the pathophysiology of this cancer, the mortality rate caused by it has not been effectively reduced. Recently, microRNAs have aroused great interest among scientists and clinicians, as they are negative regulators of gene expression, which participate in many processes, including those related to the development of pancreatic cancer. The aim of this review is to show how microRNAs (miRNAs) affect key signaling pathways and related cellular processes in pancreatic cancer development, progression, diagnosis and treatment. We included the results of in vitro studies, animal model of pancreatic cancer and those performed on blood, saliva and tumor tissue isolated from patients suffering from PDAC. Our investigation identified numerous dysregulated miRNAs involved in KRAS, JAK/STAT, PI3/AKT, Wnt/β-catenin and TGF-β signaling pathways participating in cell cycle control, proliferation, differentiation, apoptosis and metastasis. Moreover, some miRNAs (miRNA-23a, miRNA-24, miRNA-29c, miRNA-216a) seem to be engaged in a crosstalk between signaling pathways. Evidence concerning the utility of microRNAs in the diagnosis and therapy of this cancer is poor. Therefore, despite growing knowledge of the involvement of miRNAs in several processes associated with pancreatic cancer, we are beginning to recognize and understand their role and usefulness in clinical practice.

Sex Matters-Insights from Testing Drug Efficacy in an Animal Model of Pancreatic Cancer.

Preclinical studies rarely test the efficacy of therapies in both sexes. The field of oncology is no exception in this regard. In a model of syngeneic, orthotopic, metastasized pancreatic ductal adenocarcinoma we evaluated the impact of sex on pathological features of this disease as well as on the efficacy and possible adverse side effects of a novel, small molecule-based therapy inhibiting KRAS:SOS1, MEK1/2 and PI3K signaling in male and female C57BL/6J mice. Male mice had less tumor infiltration of CD8-positive cells, developed bigger tumors, had more lung metastasis and a lower probability of survival compared to female mice. These more severe pathological features in male animals were accompanied by higher distress at the end of the experiment. The evaluated inhibitors BI-3406, trametinib and BKM120 showed synergistic effects in vitro. This combinatorial therapy reduced tumor weight more efficiently in male animals, although the drug concentrations were similar in the tumors of both sexes. These results underline the importance of sex-specific preclinical research and at the same time provide a solid basis for future studies with the tested compounds.

Intratumoral Biosynthesis of Gold Nanoclusters by Pancreatic Cancer to Overcome Delivery Barriers to Radiosensitization.

Nanoparticle delivery to solid tumors is a prime challenge in nanomedicine. Here, we approach this challenge through the lens of biogeochemistry, the field that studies the flow of chemical elements within ecosystems as manipulated by living cellular organisms and their environments. We leverage biogeochemistry concepts related to gold cycling against pancreatic cancer, considering mammalian organisms as drivers for gold nanoparticle biosynthesis. Sequestration of gold nanoparticles within tumors has been demonstrated as an effective strategy to enhance radiotherapy; however, the desmoplasia of pancreatic cancer impedes nanoparticle delivery. Our strategy overcomes this barrier by applying an atomic-scale agent, ionic gold, for intratumoral gold nanoparticle biosynthesis. Our comprehensive studies showed the cancer-specific synthesis of gold nanoparticles from externally delivered gold ions in vitro and in a murine pancreatic cancer model in vivo; a substantial colocalization of gold nanoparticles (GNPs) with cancer cell nuclei in vitro and in vivo; a strong radiosensitization effect by the intracellularly synthesized GNPs; a uniform distribution of in situ synthesized GNPs throughout the tumor volume; a nearly 40-day total suppression of tumor growth in animal models of pancreatic cancer treated with a combination of gold ions and radiation that was also associated with a significantly higher median survival versus radiation alone (235 vs 102 days, respectively).

Pancreatic Cancer: An Exocrine Tumor with Endocrine Characteristics.

To examine the characteristics of pancreatic cancer patients with long-term survival. Although pancreatic cancer is a highly lethal malignancy, a minority of patients experience long-term survival. The characteristics of these patients remain largely unidentified. An indolent subgroup was established using carbohydrate antigen 19-9 (CA19-9), which is the best-validated biomarker for pancreatic cancer. Of 1558 patients, 13.9% were included in the CA19-9-normal (≤ 37U/mL) subgroup. A normal A19-9 level was an independent variable for overall survival (median survival, 18.1 vs. 9.7 months, hazard ratio = 0.53, P < 0.001). The 5-year survival of patients with stage IV CA19-9-normal cancer was higher than that of patients with stage I-IV CA19-9-high cancer (22.4% vs. 6.8%, P = 0.034). The CA19-9-normal subgroup exhibited reduced levels of circulating glucose (P < 0.001) and increased expression of insulin (P < 0.001) compared with the CA19-9-high subgroup. Glucose was a substrate for CA19-9 biosynthesis through the hexosamine biosynthesis pathway. In addition, in pancreatic cancer animal models of diabetes, glucose control decreased CA19-9 levels and improved overall survival. In a clinical trial (NCT05306028) of patients before undergoing major anticancer treatments, glucose control decreased CA19-9 levels in 90.9% of the patients. CA19-9-normal pancreatic cancer is a strikingly indolent subgroup with low glucose and high insulin. Glucose control is a promising therapeutic strategy for pancreatic cancer.

Successful In Situ Targeting of Pancreatic Tumors in a Novel Orthotopic Porcine Model Using Histotripsy.

New therapeutic strategies and paradigms are direly needed to treat pancreatic cancer. The absence of a suitable pre-clinical animal model of pancreatic cancer is a major limitation to biomedical device and therapeutic development. Traditionally, pigs have proven to be ideal models, especially in the context of designing human-sized instruments, perfecting surgical techniques and optimizing clinical procedures for use in humans. However, pig studies have typically focused on healthy tissue assessments and are limited to general safety evaluations because of the inability to effectively model human tumors. Here, we establish an orthotopic porcine model of human pancreatic cancer using RAG2/IL2RG double-knockout immunocompromised pigs and treat the tumors ex vivo and in vivo with histotripsy. Using these animals, we describe the successful engraftment of Panc-1 human pancreatic cancer cell line tumors and characterize their development. To illustrate the utility of these animals for therapeutic development, we determine for the first time, the successful targeting of in situ pancreatic tumors using histotripsy. Treatment with histotripsy resulted in partial ablation in vivo and reduction in collagen content in both in vivo tumor in pig pancreas and ex vivo patient tumor. This study presents a first step toward establishing histotripsy as a non-invasive treatment method for pancreatic cancer and exposes some of the challenges of ultrasound guidance for histotripsy ablation in the pancreas. Simultaneously, we introduce a highly robust model of pancreatic cancer in a large mammal model that could be used to evaluate a variety biomedical devices and therapeutic strategies.

Photodynamic eradication of intratumoral microbiota with bacteria‐targeted micelles overcomes gemcitabine resistance of pancreatic cancer

AbstractIncreasing evidence suggests that intratumoral microbiota plays a pivotal role in tumor progression, immunosurveillance, metastasis, and chemosensitivity. Particularly, in pancreatic ductal adenocarcinoma, tumor‐resident Gammaproteobacteria could transform the chemotherapeutic drug gemcitabine (Gem) into its inactive form, thus rendering chemotherapy ineffective. Herein, a strategy for selectively eradicating intratumoral bacteria was described for overcoming Gem resistance in a pancreatic cancer animal model. An antimicrobial peptide was linked with photosensitizer through a poly (ethylene glycol) chain, which can self‐assemble into micelles with a diameter of ∼20 nm. The micelles could efficiently kill bacteria under light irradiation by inducing membrane depolarization, thereby inhibiting Gem metabolism. In a bacteria‐resident pancreatic cancer animal model, the selective photodynamic eradication of intratumoral bacteria was demonstrated to efficiently reverse Gem resistance. This research highlights antibacterial photodynamic therapy as a promising adjuvant strategy for cancer therapy by modulating intratumoral microbiota.

Abstract 6516: Comparison study between a ketogenic diet and a high-fat diet on pancreatic cancer incidence in mice

Abstract Pancreatic Ductal Adenocarcinoma (PDAC) remains among the most lethal cancers. PDAC can take up to 15-20 years to develop from the occurrence of the first initiating mutational event, which opens the opportunity for intervention and prevention strategies. In particular, nutritional interventions could provide an avenue to prevent or slow down pancreatic carcinogenesis, since certain diets such as high-fat diets (HFD) have shown to promote it. On the other hand, ketogenic diets (KD), characterized by a high fat and very low carbohydrate content, have gained attention for their anti-tumor and anti-inflammatory potential. However, the role of a KD in the onset and progression of PDAC is still unknown. In this project, we investigated the impact of both a HFD and a KD on late-stage pancreatic carcinogenesis. For this purpose, we used an animal model of pancreatic cancer carrying a pancreas-specific oncogenic KRASG12D mutation [LSL-KRASG12D; P48+/Cre; (KC mice)]. On average, KC mice develop PDAC at 12-15 months of age, so they are a valuable tool to study late-stage carcinogenesis. We hypothesized that a HFD would accelerate PDAC progression while a KD would slow it down. To test our hypothesis, 6 months-old male and female KC mice (n=18/group) were randomized and fed, either a control diet (CD), a HFD, or a KD for 6 months and then euthanized at 12-months of age to evaluate pancreatic cancer incidence and progression. At 12-months of age, HFD-fed mice had significantly higher body weight compared to the other two groups. Moreover, KD-fed mice had significantly higher levels of blood ketone bodies, with lower levels of glucose and serum insulin levels, when compared to KC mice fed a HFD. However, after 6 months on the diets, no significant differences in pancreas weight nor in PDAC incidence were observed across all diet groups. Of note, male KC mice experienced double the PDAC incidence rates (55%) than female KC mice (27%), irrespectively of the group. In addition, no significant differences among the groups were observed in RAS/RAF/ERK and PI3K/AKT/mTOR pathways, known to be associated with cancer proliferation. In summary, despite the improvement in insulin and increases in ketone bodies, consumption of a strict KD failed to improve late-stage pancreatic carcinogenesis in mice. Citation Format: Tarek Bacha, Natalia Cortez Penso, Maria Rodriguez, Brian Hong, Gerardo Mackenzie. Comparison study between a ketogenic diet and a high-fat diet on pancreatic cancer incidence in mice. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6516.

Pre-existing TGF-β-specific T-cell immunity in patients with pancreatic cancer predicts survival after checkpoint inhibitors combined with radiotherapy

BackgroundCirculating transforming growth factor-β (TGF-β)-specific T cells that recognize TGF-β-expressing immune regulatory cells have been described in patients with cancer. TGF-β-derived peptide vaccination modulates the tumor microenvironment and has shown...

Feasibility of implantable microdosing devices to perform in vivo pharmacotyping in pancreatic cancer.

742 Background: Current biomarkers offer modest predictive capacity for drug sensitivity testing in pancreatic cancer. Patient-specific pharmacotyping offers the potential for a more direct, personalized prediction model. Recently, an implantable microdevice was developed to facilitate in situ multi-agent pharmacotyping and has since entered clinical trials in multiple cancer types, but had not yet been tested in pancreatic cancer. Here we evaluated the use of a microdosing device (microdevice) in a mouse xenotransplant model of pancreatic cancer as proof of principle to inform future translation to the clinic. Methods: A microdevice consists of a cylindrical frame and 18 wells embedded with standard chemotherapy agents (5 FU, gemcitabine, SN 38, paclitaxel, oxaliplatin), a non-toxic polyethylene glycol (PEG) matrix as control, and doxorubicin, the auto-fluorescent properties of which allow us to determine the distance of drug diffusion for each tumor. Devices were implanted into murine xenotransplanted human organoids (hM1A and hM1E Table 1). Microdevices retrieved at 4h, 8h, and 24h post-implantation together with tumors were fixed in 10% formalin. The tissue was embedded in paraffin and sectioned parallel to the device. A distance-dependent drug diffusion rate and concentration profiles with doxorubicin were evaluated. Co-immunohistochemistry (IHC) for cleaved caspase-3 (CC3), gamma H2AX (apoptosis markers), and human mitochondria (human cancer cell marker) was performed in the area of drug diffusion to determine the cytotoxic effects of chemotherapy. Results: 15 animals were enrolled in the experiment with 100% postoperative survival. One device per animal was placed, and all devices were successfully retrieved. Microdevice insertion and exposure to PEG had no effect on tumor integrity. At 250-350µm from the well, we observed intensity from doxorubicin, suggesting drug diffusion. The signal on differential response to drugs was detected as early as 4 hours. Conclusions: Utilization of implantable microdevice to predictcancer drug sensitivity is feasible in organoid transplantation animal models of pancreatic cancer. Future work is needed to expand this model to other cancer drugs and biomarkers to evaluate the cancer drug sensitivity and to test the feasibility of this model to study the effects of chemotherapy on the tumor microenvironment. [Table: see text]

PARP1 controls the transcription of CD24 by ADP-ribosylating the RNA helicase DDX5 in pancreatic cancer.

The PARP1 protein plays a key role in DNA damage repair and ADP-ribosylation to regulate gene expression. Strategies to target PARP1 have rapidly been developed for cancer treatment. However, the role of the innate immune response in targeted anti-PARP1 therapy remains poorly understood. In this work, we aimed to elucidate the regulatory mechanism underlying the immunogenicity of PARP1 and explore efficient therapeutic strategies to enhance the antitumor effect of PARP inhibitors. The relationships between PARP1 expression and immunosuppressive factors were examined by qRTPCR and immunoblot analysis. DNA pull-down, chromatin immunoprecipitation-quantitative PCR (ChIPqPCR) and luciferase reporter assays were employed to reveal the mechanism by which the expression of the immune checkpoint regulator CD24 is regulated by PARP1. Phagocytosis assays and pancreatic cancer animal models were applied to evaluate the therapeutic effect of simultaneous disruption of PARP1 and the antiphagocytic factor CD24. Upregulation of the innate immunosuppressive factor CD24 was observed in pancreatic cancer during PARP1 inhibition. The activating effect of targeting CD24 on macrophage phagocytosis was verified. Then, we showed that PARP1 attenuated the transcription of CD24 by ADP-ribosylating the transcription factor DDX5 in pancreatic cancer. Combined blockade of PARP1 and the antiphagocytic factor CD24 elicited a synergetic antitumor effect in pancreatic cancer. Our research provided evidence that combination treatment with PARP inhibitors and CD24 blocking monoclonal antibodies (mAbs) could be an effective strategy to improve the clinical therapeutic response in pancreatic cancer.

Abstract A071: XNW14010:A highly selective KRASG12C inhibitor with potent efficacy in animal model of pancreatic cancer

Abstract KRAS mutations are frequently found in various types of cancers with an overall mutation frequency of 19.3%. G12C mutation of KRAS (KRASG12C) represents 11.4% of all KRAS mutations in cancer. Targeting KRAS mutations as a cancer treatment strategy has long been investigated for over 30 years already but still remains unconquered field. XNW14010 is a highly selective KRASG12C inhibitor that is rationally designed from AMG510, another proven covalent inhibitor of KRASG12C with potential antineoplastic activity. Compared to AMG510, XNW14010 demonstrated a better pharmaceutical potential and a better safety profile. XNW14010 does not have an axial chiral center shown in AMG510, thus the production cost of this agent could be vastly reduced. The in vitro efficacy of XNW14010 was tested in a variety of cancer cell lines with either wild type KRAS or different mutant KRAS, including lung cancer, colorectal cancer, and pancreatic cancer. The result shows that XNW14010 potently inhibits the activity of KRASG12C, but not wild type KRAS or KRAS bearing other mutations. Specifically, in a pancreatic cancer cell line MIA PaCa-2, which bears KRASG12C, the IC50 of XNW14010 is 26 nM. Furthermore, XNW14010 demonstrated a much less plasma protein binding (PPB) than AMG510 (50.4% versus 93.2%, respectively), suggesting much great potential to penetrating into tumor tissue for XNW14010 compared to AMG510. XNW14010 exhibited comparable or superior pharmacokinetic characteristics compared to AMG510 after oral administration in animal studies. More interestingly, XNW14010 has an improved brain penetration capability. The brain/plasma ratio of XNW14010 exposure is two folds as high as that of AMG510 and the Cmax of XNW14010 in brain tissue is also much higher. XNW14010 had a wider therapeutic window and good tolerance compared to AMG510, both in mouse and dog models, suggesting potentially better safety profile in humans. We also compared the antineoplastic activity of XNW14010 with that of AMG510 in vivo in Xenograft mouse models including lung cancer, colorectal cancer, and pancreatic cancer. The results demonstrated that XNW14010 has comparable antineoplastic activities to AMG510 when administered at the same doses. In pancreatic cancer, the total growth inhibition (TGI) is 90% when administered at the dose of 10 mg/kg QD. Given the better PPB, superior brain penetrating capacity, and similar antineoplastic activitie of XNW14010 compared to AMG510 in non-clinical studies, XNW14010 is expected to be a potent therapeutic candidate in treating cancers bearing KRASG12C, including pancreatic cancer. Citation Format: Yonghan Hu, Xin Li, Bin Huang, Liang Kong, Meijie Le, Yan Li, Cungang Liu, Xiaojun Liu, Bin Qian, Jing Qiang, Qifeng Shi, Wengui Wang, Yuchuan Wu, Zhenwei Wu, Linfeng Xu, Jinfeng Zhao. XNW14010:A highly selective KRASG12C inhibitor with potent efficacy in animal 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 A071.

Comparative study on the antitumor effects of gemcitabine polybutylcyanoacrylate nanoparticles coupled with anti-human MUC1 and CA199 monoclonal antibodies on pancreatic cancer in vitro and in vivo

Background and Study AimsThis study was designed to compare the antitumor effects of anti-human MUC1 monoclonal antibody with those of anti-human CA199 monoclonal antibody coupled with drug-loaded polybutylcyanoacrylate nanoparticles on human pancreatic cancer cell lines and pancreatic cancer-bearing model animals and to screen more efficient targeting molecules. Patients and MethodsGemcitabine-loaded nanospheres were prepared by emulsion polymerization (GEM-PBCA-NP), and then, anti-MUC1 monoclonal antibody was coupled with GEM-PBCA-NP (MUC1-GEM-PBCA-NP), and anti-human CA199 monoclonal antibody was coupled with GEM-PBCA-NP (CA199-GEM-PBCA-NP), using the chemical crosslinking method. The cell-killing rates were detected using MTT assay. The changes in the tumor cell cycle and apoptosis after treatment were detected using flow cytometry. Then, the subcutaneous planting method was adopted to establish an animal model of pancreatic cancer: two nanometer microspheres were injected into the body of nude mice via the tail vein; the tumor suppression effect was detected after treatment; then, the groups were compared. ResultsIn vitro, the cell-killing rate of each experimental group was significantly different from that of the control group (P < 05). The MUC1-GEM-PBCA-NP group had a significantly higher cell-killing rate than the other groups (P < 05). The apoptosis rate of the MUC1-GEM-PBCA-NP treatment group was significantly higher than that of other groups (P < 05). In vivo, the tumor inhibition rate of the MUC1-GEM-PBCA-NP treatment group was 72.69% ± 4.29%, which was significantly higher than those of other groups (P < 0.05). The tumor inhibition rate of the CA199-GEM-PBCA-NP treatment group was 56.58% ± 5.11%, which was significantly higher than those of other control groups (P < 0.05). At the end of treatment, the average tumor mass of the MUC1-GEM-PBCA-NP treatment group was 433.55 ± 12.49 mg, which was significantly lower than those of other groups (P < 0.05). ConclusionCompared with CA199-GEM-PBCA-NP, MUC1-GEM-PBCA-NP is more effective in vitro and in vivo. MUC1 could be a target molecule in treating pancreatic cancer.

Abstract 2483: Detection of STING-induced immune activation via [18F]FDG-PET imaging

Abstract Stimulator of interferon genes (STING) coordinates innate and adaptive immune responses by mediating type I interferon and NF-κB signaling and is therefore a promising cancer immunotherapy target. While first generation STING agonists have advanced to multiple clinical trials, their application is restricted to intratumoral administration and these agents have shown limited therapeutic efficacy. In contrast, recently developed second generation STING agonists allow for systemic administration and have been shown to exert highly potent anti-tumor effects in animal models of cancer. However, STING is expressed in a wide array of cell types and tissues, and the effects of systemic activation of this pattern recognition receptor are poorly understood. This highlights the need for the development of pharmacodynamic companion biomarkers that can be used to guide the clinical development of newly developed systemic STING agonists. Here, we show that systemic administration of the STING agonist diABZI triggers alterations in glucose metabolism in immune cells which can be detected non-invasively using [18F]Fluorodeoxyglucose (FDG) and positron emission tomography (PET). Accordingly, systemic STING activation significantly upregulated [18F]FDG uptake in secondary lymphoid organs, such as the spleen and lymph nodes, as indicated by PET imaging in vivo and confirmed by gamma counter measurements of isolated splenocytes ex vivo. Importantly, STING agonist-induced changes in [18F]FDG uptake in the spleen and lymph nodes were highly predictive of therapeutic responses to STING agonist mono- and combination therapies in animal models of pancreatic cancer. Using single-cell RNA sequencing we found that systemic STING activation triggers profound transcriptional alterations in T and B lymphocytes indicative of a metabolic shift towards enhanced glycolysis. We then explored whether metabolic alterations indicated by increased [18F]FDG uptake are associated with changes in the functional phenotypes of T and B cells. We found that systemic STING activation induced the upregulation of the early activation marker CD69 and immune checkpoint ligand PD-L1. Furthermore, CD69 and PD-L1 upregulation occurred in a STING agonist dose-dependent manner that correlated with [18F]FDG uptake as measured non-invasively by PET. In interferon receptor knockout mice, CD69 and PD-L1 expression was partially attenuated; however, [18F]FDG uptake was still induced following STING activation, suggesting that an interferon-independent mechanism mediates the observed glycolytic switch in lymphocytes. In summary, [18F]FDG-PET provides a novel non-invasive and widely applicable pharmacodynamic biomarker which has potential to guide and accelerate the clinical development of systemic STING agonist-based immunotherapies in immunologically cold malignancies. Citation Format: Hailey R. Lee, Evan R. Abt, Khalid Rashid, Amanda L. Creech, Keke Liang, Liu Wei, Arthur Cho, Willy Hugo, Timothy R. Donahue, Johannes Czernin, Caius G. Radu, Thuc M. Le. Detection of STING-induced immune activation via [18F]FDG-PET imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2483.

Aurora kinase a inhibitor MLN8237 suppresses pancreatic cancer growth

Pancreatic ductal adenocarcinoma (PDAC) is notorious for high mortality due to limited options of appropriate chemotherapy drugs. Here we report that Aurora kinase-A expression is elevated in both human and mouse PDAC samples. MLN8237, an inhibitor of Aurora kinase-A, efficiently reduced the proliferation and motility of PDAC cells in vitro as well as tumor growth in orthotropic xenograft model and genetic pancreatic cancer animal models (p53/LSL/Pdx-Cre mice) in vivo. MLN8237 exhibited tumor inhibitory effect through inhibiting proliferation and migration, and inducing apoptosis and senescence. These results provide the molecular basis for a novel chemotherapy strategy for PDAC patients.

Establishment of a pancreatic cancer animal model using the pancreas-targeted hydrodynamic gene delivery method

This research developed an easy-to-use, reproducible pancreatic cancer animal model utilizing pancreas-targeted hydrodynamic gene delivery to deliver human pancreatic cancer-related genes to the pancreas of wild-type rats. KRASG12D-induced pancreatic intraepithelial neoplasia lesions showed malignant transformation in the main pancreatic duct at 4 weeks and developed acinar-to-ductal metaplasia, which led to pancreatic ductal adenocarcinoma within 5 weeks, and the gene combination of KRASG12D and YAP enhanced these effects. The repeat hydrodynamic gene delivery of KRASG12D + YAP combination at 4 weeks showed acinar-to-ductal metaplasia in all rats and pancreatic ductal adenocarcinoma in 80% of rats 1 week later. Metastatic tumors in the liver, lymph nodes, and subcutaneous lesions and nervous invasion were confirmed. KRASG12D and YAP combined transfer contributes to the E- to N-cadherin switch in pancreatic ductal adenocarcinoma cells and to tumor metastases. This pancreatic cancer model will speed up pancreatic cancer research for novel treatments and biomarkers for early diagnosis.

Establishment of a mouse model of pancreatic cancer using human pancreatic cancer cell line S2-013-derived organoid

A well-established preclinical model of pancreatic cancer needs to be established to facilitate research on new therapeutic targets. Recently established animal models of pancreatic cancer, including patient-derived tumor models and organoid models, are used for pre-clinical drug testing and biomarker discovery. These models have useful characteristics over conventional xenograft mouse models based on cell lines in preclinical studies, but still cannot accurately predict the clinical outcomes of new treatments and have not yet been broadly implemented in research. We employed pancreatic cancer organoid culture methods using the pancreatic cancer cell line S2-013, and performed pathological and immunohistochemical analyses to characterize tumor xenografts obtained from a mouse model implanted with S2-013 cell line-derived organoids. Serum levels of the pancreatic cancer tumor marker CA19-9 were measured by ELISA. We generated human pancreatic cancer organoids using a co-culture of S2-013 cells, human endothelial cells derived from human umbilical vein endothelial cells, and human mesenchymal stem cells, and established a mouse model with subcutaneously transplanted human pancreatic cancer organoids (S2-013-organoid model). Although blood clotting crater-like formation developed in the middle of subcutaneous xenografts in the S2-013-conventional model, created by subcutaneously injecting S2-013 cells into the right flank of nude mice, the size of xenografts in the S2-013-organoid model gradually increased without crater-like formation. Importantly, tumor xenografts obtained from the S2-013-organoid model exhibited a clinical human pancreatic cancer tissue-like cellular morphology, tissue architecture, and polarity, and actively formed cancer stroma containing mature blood vessels with the high expression of the vascular tight junction marker CD31. In subcutaneous xenografts of S2-013-conventional mice, no blood vessel density or widely expanding areas of necrotic regions were present. Consequently, serum levels of CA19-9 in the S2-013-organoid model correlated with tumor volumes. In addition, epithelial–mesenchymal transition, the conversion of epithelial cells to the mesenchymal phenotype, was observed in tumor xenografts of the S2-013-organoid model. The S2-013-organoid model provides tumor xenografts consisting of clinical human pancreatic cancer-like tissue formation with the effective development of vascularized stroma, and may be valuable for facilitating studies on pre-clinical drug testing and biomarker discovery.

Cover - Tumor Infiltrating Lymphocytes in an Animal Model of Pancreatic Cancer

Cover - Tumor Infiltrating Lymphocytes in an Animal Model of Pancreatic Cancer

Phospho-Aspirin (MDC-22) inhibits pancreatic cancer growth in patient-derived tumor xenografts and KPC mice by targeting EGFR: Enhanced efficacy in combination with irinotecan.

Novel therapeutic strategies are needed in the fight against pancreatic cancer. We have previously documented the chemopreventive effect of MDC-22 in preclinical models of pancreatic cancer. In the present work, we examined the therapeutic effects of MDC-22 in patient-derived tumor xenografts (PDTXs) and in LSL-KrasG12D/+, LSL-Trp53R172H/+, Pdx1-Cre (KPC) genetically engineered mice, two complementary and clinically relevant animal models of pancreatic cancer. In addition, we evaluated whether MDC-22 could synergize with current chemotherapeutic drugs used in the clinic. MDC-22 reduced the growth of various human pancreatic cancer cell lines in a concentration-dependent manner. In vivo, MDC-22 strongly reduced patient-derived pancreatic tumor xenograft growth by 50%, and extended survival of LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre (KPC) mice by over a month (5.3 months versus 7.0 months). In both models, MDC-22 inhibited EGFR activation and its downstream signals, including ERK and FAK phosphorylation. In human pancreatic cancer cell lines, MDC-22 enhanced the growth inhibitory effect of irinotecan, and to a lesser degree those of gemcitabine and nab-paclitaxel. Normal human pancreatic epithelial cells were more resistant to the cytotoxic effects of, both, MDC-22 alone or in combination with irinotecan, indicating selectivity. Furthermore, MDC-22 enhanced irinotecan's effect on cell migration, in part, by inhibiting EGFR/FAK signaling. Collectively, our results indicate that MDC-22 is an effective anticancer drug in preclinical models of pancreatic cancer, and suggest that MDC-22 plus irinotecan as drug combination strategy for pancreatic cancer treatment, which warrants further evaluation.

Therapeutic effiacy of T cells expressing chimeric antigen receptor derived from a mesothelin-specific scFv in orthotopic human pancreatic cancer animal models.

Novel CAR T cells targeting mesothelin (MSLN) expressed on pancreatic cancer cells were developed to overcome the limit of the clinical efficacy of CAR T cell therapy for pancreatic cancer patients. Optimal single-chain variable fragments (scFv) binding to MSLN were selected based on the binding activity and the functional effectiveness of various scFv containing CAR-expressing T cells. Engineered MSLN CAR T cells showed successful anti-tumor activity specific to MSLN expression level. Furthermore, MSLN CAR T cells were evaluated for the anti-cancer efficacy in orthotopic mouse models bearing pancreatic cancer cells, MIA Paca-2, MSLN-overexpressed MIA Paca-2 or endogenously MSLN-expressing AsPC-1. Mice were randomized into control, mock treated, MS501 BBz treated, MS501 28z treated or MS501 28BBz treated group. Mice were monitored by weekly IVIS imaging and tumors were harvested and analyzed by immunohistochemical analyses. MSLN CAR T cells produced the therapeutic effect in orthotopic animal models with complete remission in significant number of mice. Histopathological analysis indicated that CD4+ and CD8+ MSLN CAR T cells infiltrated pancreatic tumor tissue and led to cancer cell eradication. Our results demonstrated the anti-tumor efficacy of MSLN CAR T cell therapy against pancreatic cancer, suggesting its therapeutic potential.