Orthotopic Pancreatic Cancer Research Articles

Establishment of a novel adjuvant model of orthotopic pancreatic cancer: Effects of HGF-cMET inhibition on disease progression

Establishment of a novel adjuvant model of orthotopic pancreatic cancer: Effects of HGF-cMET inhibition on disease progression

Synergistic Cytotoxicity and Co-Autophagy Inhibition in Pancreatic Tumor Cells and Cancer Associated Fibroblasts by Dual Functional Peptide Modified Liposomes

Pancreatic ductal adenocarcinoma (PDA) is a highly fatal disease with 5-year survival of ~4%. Nanoplatforms such as nab-paclitaxel and nanoliposomal irinotecan demonstrate superiority and utility in treating different progressions of PDA by prolonging the median overall survival (by) only a few months. Due to the dense surrounding stroma and the high autophagy in pancreatic cancer, integrin ɑvβ3 targeting, acid environmental sensitive, TR peptide modified liposomal platforms loaded with combined autophagy inhibiting hydroxychloroquine (HCQ), and cytotoxic paclitaxel (PTX) were designed (TR-PTX/HCQ-Lip) to accomplish the aim of synergistically killing tumor cells while inhibiting stroma fibrosis. The results showed that TR peptide modified liposomes (TR-Lip) have superior targeting and penetrating effects both in-vitro and in-vivo. TR-PTX/HCQ-Lip efficiently inhibited autophagy in pancreatic cells and surrounding cancer associated fibroblasts. The synergistic anti-fibrosis roles were also confirmed both in-vitro and in-vivo, all of which contributes to the enhanced curative effects of TR-PTX/HCQ-Lip in both heterogenetic and orthotopic pancreatic cancer models.

Potent antitumor efficacy of ex vivo expanded and cryopreserved human natural killer cells against orthotopic pancreatic cancer

Background & Aim Natural killer (NK) cells are specialized components of the innate immune system that contribute to the first line of defense against viral infections and cancer. Ex vivo expanded NK cells are a promising tool for the use in adoptive immunotherapy. Pancreatic cancer is one of the most aggressive tumor types and severely limits the therapeutic efficacy of both immunotherapeutics and conventional chemotherapeutics because ECM act as a major physical barrier against drug penetration. Methods, Results & Conclusion To address these challenges, we expanded and cryopreserved allogeneic NK cells. And cryopreserved NK cells were evaluated for their therapeutic efficacy against desmoplastic pancreatic tumors, ultimately aiming to develop easily accessible and mass-producible off-the-shelf cell-based immunotherapeutics. Ex vivoexpanded and cryopreserved cells retained highly pure and activated population of NK cells. In addition, ex vivo expanded and cryopreserved NK cells exhibited not only potent killing activity and cytokine production against various pancreatic cancer cell lines in vitro but also excellent tumor growth suppression in vivo orthotopic pancreatic cancer model. In conclusion, ex vivo expanded and cryopreserved NK cells are a strong candidate for future cell-mediated systemic immunotherapy against pancreatic cancer.

Cavitation-induced release of liposomal chemotherapy in orthotopic murine pancreatic cancer models: A feasibility study

To study the feasibility and efficacy of a combination of focused US and liposomal doxorubicin (US-L-DOX) release in orthotopic murine models of pancreatic cancer. A confocal US setup was developed to generate US inertial cavitation delivery in a controlled and reproducible manner and designed for two distinct murine orthotopic pancreatic cancer models. Controlled cavitation at 1 MHz was applied within the tumors after L-DOX injection according to a preliminary pharmacokinetic study. In vitro studies confirmed that L-DOX was cytostatic. In vivo pharmacokinetic study showed L-DOX peak tumor accumulation at 48h. Feasibility of L-DOX injection and US delivery was demonstrated in both murine models. In a nude mouse model, at W9 after implantation (W5 after treatment), US-L-DOX group (median [IQR] 51.43 mm3 [35.1-871.95]) exhibited significantly lower tumor volumes than the sham group (216.28 [96.12-1202.92]), the US group (359.44 [131.48-1649.25]), and the L-DOX group (255.94 [84.09-943.72]), and a trend, although not statistically significant, to a lower volume than Gemcitabine group (90.48 [42.14-367.78]). This study demonstrates that inertial cavitation can be generated to increase the therapeutic effect of drug-carrying liposomes accumulated in the tumor. This approach is potentially an important step towards a therapeutic application of cavitation-induced drug delivery in pancreatic cancer.

Study inhibition and apoptosis of peripheral blood dendritic cells hybridize tumor vaccine induced systematic immune effector cells to the BxPC-3 in vitro

Objective To observe the inhibition and apoptosis effects of systematic immune effector cells (SIECs) induced by increased expansion of normal human peripheral venous blood dendritic cells (DCs) hybridoma vaccine on orthotopic pancreatic cancer cell line (BxPC-3) in vitro. Methods The peripheral blood mononuclear cells (PBMCs) of healthy human were obtained by gradient centrifugation of lymphocyte separation fluid, and DCs and DCs derived monocytes cells (SIECs) were obtained by adherent method. DCs and SIECs were respectively cultured with granulocyte macrophage-colony stimulating factor (GM-CSF), interleukin (IL)-4, tumor necrosis factor-α (TNF-α), IL-2, BxPC-3 tumor specific antigen (pc-3tsa). After five days, DCs were collected and counted. BxPC-3TAA-sensitized DCs (referred to as sensitive DCs), and DCs were fused with BxPC-3 by PEG+ 10% dimethylsurfoxide (DMSO) with 10∶1, 5∶1, 1∶5 to obtain sensitive DCs-BxPC-3 and DCs-BxPC-3 fusion tumor vaccines. On the 7th day, SIECs were respectively mixed with sensitive DCs-BxPC-3, DCs-BxPC-3, sensitive DCs, and DCs for 1 days in a 40∶1 mixture. The mixed cultured cells were collected, and the Annexin V-fluoresceine isothiocyanate (FITC)/propidium iodide (PI) apoptosis assay and cell counting kit-8 (CCK-8) toxicity assay were performed on BxPC-3 in the mixed target SIECs∶BxPC3=10∶1. Results The sensitives DCs, DCs and BxPC-3 were fused, and the fusion effect was the best when the ratio was 1∶1, and the fusion rate was 40.0%. The CCK-8 assay showed that the inhibition rates of BxPC-3 induced by SIECs and SIECs by sensitive DCs-BxPC-3, DCs-BxPC-3, sensitive DCs and DCs were 53.1%, 45.3% and 78.8%, respectively. The Annexin V-FITC/PI assay showed that apoptosis rates of sensitive DCs-BxPC-3, DCs-BxPC-3, sensitive DCs, DCs and SIECs were 24.17%, 11.43%, 85.87% and 29.94%. Conclusion Tumor antigen sequential sensitization DCs have a superimposed effect on antigen acquisition, which can play a better anti-tumor effect. Early DCs fusion tumor vaccine can induce SIECs to inhibit tumor cells to a certain extent. Key words: Dendritic cells; Sequential sensitization; Pancreatic cancer; Tumor vaccine; Cell inhibition; Apoptosis

Targeted Co-delivery of the Iron Chelator Deferoxamine and a HIF1α Inhibitor Impairs Pancreatic Tumor Growth.

Rapidly growing cancer cells exhibit a strong dependence on iron for their survival. Thus, iron-removing drugs, iron chelators, have potential applications in cancer treatment. Deferoxamine (DFO) is an efficient iron chelator, but its short circulation half-life and ability to induce hypoxia-inducible factor 1α (HIF1α) overexpression restricts its use as an antitumor agent. In the present study, we first found that a pattern of iron-related protein expression favoring higher intracellular iron closely correlates with shorter overall and relapse-free survival in pancreatic cancer patients. We subsequently found that a combination of DFO and the HIF1α inhibitor, lificiguat (also named YC1), significantly enhanced the antitumor efficacy of DFO in vitro. We then employed transferrin receptor 1 (TFR1) targeting liposomes to codeliver DFO and YC1 to pancreatic tumors in a mouse model. The encapsulation of DFO prolonged its circulation time, improved its accumulation in tumor tissues via the enhanced permeability and retention (EPR) effect, and facilitated efficient uptake by cancer cells, which express high level of TFR1. After entering the tumor cells, the encapsulated DFO and YC1 were released to elicit a synergistic antitumor effect in subcutaneous and orthotopic pancreatic cancer xenografts. In summary, our work overcame two major obstacles in DFO-based cancer treatment through a simple liposome-based drug delivery system. This nanoencapsulation and targeting paradigm lays the foundation for future application of iron chelation in cancer therapy.

The Use of Star Polymer Nanoparticles for theDelivery of siRNA to Mouse Orthotopic Pancreatic Tumor Models.

Pancreatic cancer is a lethal malignancy which is refractory to most chemotherapy drugs. Recent landmark studies have shed new light on the complex genetic heterogeneity of pancreatic cancer and provide an opportunity to utilize "precision-based medicines" to target genes based on the genetic profile of an individual's tumor to increase the efficiency of chemotherapy and decrease tumor growth and metastases. Gene-silencing drugs in the form of short-interfering RNA (siRNA) have the potential to play an important role in precision medicine for pancreatic cancer by silencing the expression of genes including those considered difficult to inhibit (undruggable) using chemical agents. However, before siRNA can reach its clinical potential a delivery vehicle is needed to carry siRNA across the cell membrane and into the cytoplasm of the cell. Herein, we detail the methods required to use star polymer nanoparticles to deliver siRNA to pancreatic tumors in an orthotopic pancreatic cancer mouse model to silence the expression of an "undruggable" gene (βIII-tubulin) that regulates pancreatic cancer growth and chemosensitivity.

Targeting carbon nanotubes based on IGF-1R for photothermal therapy of orthotopic pancreatic cancer guided by optical imaging

Pancreatic cancer is one of the most lethal malignancies worldwide. The existing therapeutic regimen in the clinic for advanced inoperable carcinomas are far from satisfactory, thus it is urgent to seek more effective anticancer strategies. In the pursuit of novel, more effective interventions, photothermal therapy (PTT) based on nanomaterials has attracted increased attention. Recent advances in related fields have catalyzed the generation of novel nanoprobes, such as organic dyes, metal nanoparticles. However, organic dyes are poorly stable and easy to quench while metal nanoparticles with potential metal toxicity are difficult to degrade, both of which have low light-to-heat conversion efficiency, broad spectrum of anti-tumor effects, and lack of tumor targeting specificity. Single-walled carbon nanotubes (SWNTs) can remedy the above inadequacies. Herein, we report our water-soluble, bio-stable and low-toxicity SWNTs with excellent photothermal conversion efficiency. Specific modifications can enable visualization of the aggregate characteristics of SWNTs at the macroscopic or microscopic level in tumors. The dye-conjugated SWNTs bound with targeting antibodies that can induce them specifically targeting to pancreatic tumors for purposes of performing dyes imaging-guided cytotoxic PTT. PTT using this method achieves precise and excellent curative effects with minimal adverse effects, thus providing a promising strategy for anticancer therapy.

SRC-3 inhibition blocks tumor growth of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant and lethal disease with few treatment options. Steroid receptor coactivator-3 (SRC-3, also known as NCOA3, AIB1, pCIP, ACTR, RAC3, TRAM1) sits at the nexus of many growth signaling pathways and has been pursued as a therapeutic target for breast, prostate and lung cancers. In this study, we find that SRC-3 is overexpressed in PDAC and inversely correlates with patient overall survival. Knockdown of SRC-3 reduces pancreatic cancer cell proliferation, migration and invasion in vitro. Additionally, inhibition of SRC-3 using either shRNA or a small molecule inhibitor can significantly inhibit tumor growth in orthotopic pancreatic cancer mouse models. Collectively, this study establishes SRC-3 as a promising therapeutic target for pancreatic cancer treatment.

Malignant Transformation of Ectopic Pancreas.

Malignant transformation of ectopic pancreas tissue is a diagnostic challenge as clinical symptoms and radiographic features of these tumors are non-specific. Given the rarity of these lesions, it is usually neither suspected nor included in the diagnostic workup of different tumors. We conducted a comprehensive literature review regarding malignancy arising from ectopic pancreas for a better understanding of its frequency, clinicopathological features, and prognosis. A literature search was performed in three major databases: PubMed, Cochrane, and Web of Science. Fifty-four well-documented cases of malignant ectopic pancreas were identified in the published literature. Our analysis provided the following observations: (1) there was a slight predominance of males over females; (2) most patients with malignant transformation of ectopic pancreas were middle-aged; (3) most commonly, the tumor was located in the stomach; (4) most tumors were adenocarcinomas; (5) most frequently, the malignancy arose within a type I heterotopia according to Heinrich classification; (6) macroscopically, a subepithelial-like appearance was most frequently observed; and (7) improved prognosis for ectopic pancreatic malignancies in comparison with reported survival data for orthotopic pancreatic cancer. Even if the majority of cases of ectopic pancreas are incidental findings and malignant transformation is a rare event, pancreatic heterotopy should be considered as a source of potentially malignant lesions.

Size-dependent Tumor Response to Photodynamic Therapy and Irinotecan Monotherapies Revealed by Longitudinal Ultrasound Monitoring in an Orthotopic Pancreatic Cancer Model.

Longitudinal monitoring of tumor size invivo can provide important biological information about disease progression and treatment efficacy that is not captured by other modes of quantification. Ultrasound enables high-throughput evaluation of orthotopic mouse models via fast acquisition of three-dimensional tumor images and calculation of volume with a reasonable degree of accuracy. Herein, we compare orthotopic pancreatic tumor volume measurements determined by ultrasound with volume measured by calipers and tumor weight, and found strong correlations between the three modalities over a large range of tumor sizes, suggesting ultrasound can accurately quantify tumor volumes in this model. Furthermore, we demonstrate the unique ability of longitudinal treatment monitoring to reveal a tumor size-dependent response to Benzoporphyrin Derivative photodynamic therapy (BPD-PDT) and irinotecan. Small tumors (5-35mm3 ) were found to respond well to a single round of PDT, while large tumors (35-65mm3 ) showed no response to the same treatment. These results highlight the role that tumor size can play in preclinical interpretation of treatment response and more generally suggest that careful evaluation of subtle biological features such as this must be carefully considered in order to grant a more comprehensive understanding of disease biology invivo.

A novel plectin/integrin-targeted bispecific molecular probe for magnetic resonance/near-infrared imaging of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest human malignancies with poor patient outcomes often resulting from delayed diagnosis. Therefore, early diagnosis can lead to a better prognosis and improved outcomes. In this study, we have developed a novel conjugate complex of plectin/integrin-targeted bispecific molecular probe, termed Gd-Cy7-PTP/RGD, to be used for magnetic resonance/near-infrared imaging (MRI/NIRF) of pancreatic cancer in vivo. This bispecific molecular probe comprises four parts: Gd(III) for MRI, cyanine 7 (Cy7) for NIRF, the peptide PTP for binding to plectin-1 specifically overexpressed on the surface of PDAC cells, and the peptide RGD for targeting integrin widely expressed on pancreatic duct epithelial cells and angiogenesis. Remarkably, the combination of PTP and RGD greatly increased the targeting efficiency in vitro and in vivo compared to that of either single peptide. Moreover, such bispecific molecular probes target pancreatic neoplasms and angiogenesis simultaneously, producing a “multi-level” targeting effect confirmed by immunofluorescence testing in vitro and in vivo. Under the guidance of MRI/NIRF dual-modality imaging, NIRF-guided delineation of surgical margins during operations was successfully achieved in orthotopic pancreatic cancer. This study promotes further exploration of bispecific molecular probes for clinical application.

MiR-361-3p regulates ERK1/2-induced EMT via DUSP2 mRNA degradation in pancreatic ductal adenocarcinoma

Metastasis remains one of the most intractable challenges in pancreatic ductal adenocarcinoma (PDAC) biology, and epithelial-to-mesenchymal transition (EMT) is essential to the epithelium-originated solid tumor metastasis cascade. Emerging evidence demonstrates that aberrant miRNA expression is involved in pancreatic cancer progression. We found that miR-361-3p was associated with an advanced stage of PDAC and poor prognosis. Hence, the effect of miR-361-3p on metastasis of PDAC cells was evaluated using Transwell assay and wound healing assay in vitro as well as orthotopic and liver metastasis pancreatic cancer models in vivo. Overexpression of miR-361-3p promoted pancreatic cancer cell migration and invasion in vitro, and miR-361-3p-elevated PDAC cells were prone to generating metastatic nodules in vivo. However, miR-361-3p showed no significant effect on the proliferation of PDAC cells in vivo or in vitro. Further study demonstrated that miR-361-3p could enhance EMT and ERK pathway activation, and ERK inhibitor could attenuate miR-361-3p-induced EMT. Luciferase assays, qPCR, and western blot and Ago2 co-immunoprecipitation were performed to identify the direct target of miR-361-3p. Mechanistic investigations identified DUSP2 as a direct target of miR-361-3p, and DUSP2 was revealed to be involved in miR-361-3p-induced EMT by directly leading to the inactivation of the ERK pathway. Moreover, we found that miR-361-3p-induced EMT was dependent on Ago2, the core component of RNA-induced silencing complex, while enforced expression of Ago2 enhanced the miR-361-3p-induced effect by promoting interference efficacy and specificity rather than regulating miR-361-3p stability and biogenesis. Thus, this study revealed that miR-361-3p functions as an oncomiR for promoting metastasis and identified the miR-361-3p/DUSP2/ERK axis as a novel EMT axis dependent on Ago2 in PDAC.

Abstract 370: Hyperpolarized magnetic resonance metabolic imaging in pancreatic cancer research: Early detection, assessing aggressiveness and real-time monitoring treatment response

Abstract Pancreatic cancer is on pace to become the second leading cause of cancer-related death. The high mortality rate results from a lack of methods for early detection and the inability to successfully treat patients once diagnosed. Pancreatic cancer cells have extensively reprogrammed metabolism, which is driven by oncogene-mediated pathways and the unique physiology of the tumor microenvironment. In our research, we are interrogating reprogrammed metabolism in pancreatic cancer. We have employed hyperpolarized metabolic imaging to measure noninvasively the metabolic plasticity as the diseases initiate, evolve and respond to the drugs. Genetically engineered mouse (GEM) model with progression of pancreatic intraepithelial neoplasm (PanIN) lesions has been used for early detection, patient-derived xenografts (PDX) model to assess aggressiveness, and orthotopic pancreatic cancer model for monitoring metabolically targeted therapeutic response. Hyperpolarization of pyruvate and in-vivo 13C MRS were performed using Hypersense (Oxford Instruments) and 7T MRI scanner with a dual tuned 1H/13C volume coil (Bruker), respectively. Tissue alanine and lactate concentrations were determined using a Bruker 500 MHz NMR spectrometer coupled with cryoprobe. Histology and immunohistochemistry were performed on excised tissue samples. Hyperpolarized pyruvate metabolism in PDX tumor was well captured in real time. Pyruvate was readily metabolized to lactate and alanine in vivo. The quantitative flux ratios lactate-to-pyruvate (Lac/Pyr) and alanine-to-lactate were determined. The most aggressive tumors showed the highest value of Lac/Pyr ratio. GEM model such as P48Cre;LSLKrasG12D mice were used for detection of early and advanced PanIN, which usually develop in these mice between 20 and 25 weeks. The imaging experiments were performed at the different stages of the disease. Progression of disease from tissue containing predominantly low-grade PanIN to tissue with high-grade PanIN showed a decreasing alanine/lactate concentration ratio as measured by 1H-NMR metabolomics. These results demonstrate that there are significant alterations of alanine transaminase (ALT) and lactate dehydrogenase (LDH) activities that favor the transformation of aggressive pancreatic cancer from PanIN lesion. The efficacy of a metabolically targeted drug was monitored in orthotopic pancreatic cancer mice by measuring flux ratio of Lac/Pyr after injecting hyperpolarized pyruvate before the tumor shrinkage. Metabolic imaging with hyperpolarized pyruvate and NMR metabolomics enabled detection and monitoring of the progression of pancreatic cancer lesions. Translation of this HP-MRI technique to the clinic has the potential to improve early detection and the management of patients' care. Citation Format: Prasanta Dutta, Erick Riquelme Sanchez, Yu Zhang, Travis Salzillo,, Priyank Raj, Jaehyuk Lee, Niki Millward, Anirban Maitra, Florencia McAllister, Pratip Bhattacharya. Hyperpolarized magnetic resonance metabolic imaging in pancreatic cancer research: Early detection, assessing aggressiveness and real-time monitoring treatment response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 370.

Abstract 2926: The glycogen synthase kinase-3 inhibitor, 9-ING-41, synergizes with chemotherapy to inhibit pancreatic tumor growth in vivo

Abstract Glycogen synthase kinase-3 (GSK3) is a ubiquitously expressed serine-threonine protein kinase involved in multiple cellular functions ranging from the control of glycogen metabolism to transcriptional regulation. We have previously demonstrated that GSK-3β is overexpressed in human pancreatic ductal adenocarcinoma (PDAC) and aberrant nuclear accumulation of GSK-3β serves as a hallmark of poorly differentiated PDAC. Moreover, genetic ablation of GSK-3β or GSK-3 inhibition led to PDAC tumor cell killing, identifying GSK-3β as a therapeutic target in PDAC. Herein, we describe a novel GSK-3 inhibitor, 9-ING-41. The effect of 9-ING-41 on tumor cell growth was tested using several PDAC and patient-derived xenograft (PDX) cell lines in vitro and in vivo using an orthotopic pancreatic cancer animal model. Interestingly, 9-ING-41 treatment resulted in the stabilization of cyclin B levels as well as enhanced serine-10 phosphorylated histone H3 (pS10HH3) and consequently M phase arrest and blocked mitotic exit. The prolonged M phase arrest induced mitotic catastrophe in pancreatic cancer cell lines and inhibited in vitro colony formation. An in vivo orthotopic pancreatic cancer animal model study using PDX-derived cell lines demonstrated that 9-ING-41 hindered tumor growth in combination with several standard chemotherapeutic agents. Significantly, we found that 9-ING-41 treatment impaired the DNA damage response pathway activated by Gemcitabine in pancreatic cancer cell lines. In conclusion, our study indicates that GSK-3 plays an important role in pancreatic cancer progression and 9-ING-41 in combination with existing gemcitabine or irinotecan could be a new strategy for treating patients with PDAC. Citation Format: Li Ding, Jin-san Zhang, John R. Dube, Vijay S. Madamsetty, Daniel M. Schmitt, Debabrata Mukhopadhyay, Daniel D. Billadeau. The glycogen synthase kinase-3 inhibitor, 9-ING-41, synergizes with chemotherapy to inhibit pancreatic tumor growth in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2926.

Abstract 4102: Surgical imaging of pancreatic cancer using near infrared fluorescent hyaluronic acid nanomaterials

Abstract Purpose: Pancreatic ductal adenocarcinoma (PDAC) has an overall 5-year survival rate for all patients of approximately 7.1%. Surgery only increases the long-term survival rate of PDAC to 12.1%. Survival could potentially be increased with better detection of pancreatic cancer during surgical resection by improved margin detection, more effective debulking of disseminated disease, and earlier detection. In this work, we utilized nanoparticle formulations of the near infrared fluorophore indocyanine green (ICG) to provide optical detection of pancreatic tumors in an orthotopic, syngeneic mouse model of PDAC. Methods: ICG was physico-chemically entrapped nanoparticles derived from amphiphilic hyaluronic acid, termed NanoICG and compared to ICG alone. Cytotoxicity and immunotoxicity of the imaging agents were determined by in vitro methods, while blood biochemistry, cell counts, and toxicological pathology, were examined in vivo. The ability to detect PDAC was determined in PDAC cells originating from KPC mice that were implanted orthotopically into syngeneic C57 mice. Contrast enhancement was determined using a combination of image-guided surgery systems and whole animal imaging systems. Results: Neither Empty NP of NanoICG affected metabolic activity toward healthy pancreatic epithelial or pancreatic adenocarcinoma cells and NanoICG displayed did not have capacity to act as a chemoattractant. In vivo, NanoICG (normalized to maximum allowed ICG dose) did not alter blood biochemical markers including HGB, ALB, ALP, ALT, AMY, BUN, GLOB, and TP or cell counts including, WBC, RBC, PLT, or HCT. Histological examination showed no toxicity related to the administration of contrast agents in liver, lung, spleen, or kidneys. In the syngeneic, orthotopic PDAC model, NanoICG accumulated significantly within the pancreas and had a 2.1-fold stronger signal compared to ICG alone. Considering contrast within PDAC compared to uninvolved healthy pancreas, NanoICG was 2.34-fold stronger (P<0.05), while contrast between PDAC and healthy pancreas with ICG was minimally detectable. Using near infrared fluorescence microscopy, area strong signal from NanoICG localized to areas of PDAC. Conclusions: NanoICG exhibited improved efficacy at detecting pancreatic tumors in an orthotopic pancreatic cancer model with negligible NP-derived toxicity, which shows NanoICG as a promising agent in pancreatic tumor diagnosis and surgical resection. Further research is being performed to minimize clearance organ uptake.<!–EndFragment–> Citation Format: Bowen Qi, Ayrianne Crawford, Samuel Cohen, Michael Hollingsworth, Aaron M. Mohs. Surgical imaging of pancreatic cancer using near infrared fluorescent hyaluronic acid nanomaterials [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4102.

Abstract 5225: PAR1 signaling on tumor cells limits tumor growth by maintaining a mesenchymal phenotype in pancreatic cancer

Abstract Background: Pancreatic cancer is a dismal disease with limited treatment options. Importantly, in recent years an oncogenic role of protease-activated receptor 1 (PAR1) emerged in various cancer types, and PAR1 is generally accepted to promote tumor progression. PAR1 depletion in stroma limits cancer growth in an orthotopic pancreatic cancer model, suggesting that PAR1 would be a prognostic marker for PDAC. Aim: To determine PAR1 expression in tumor compartment of PDAC microenvironment and its contribution to tumor progression and invasion. Methods: Kaplan-Meier overall survival analysis for PAR1 expression on PDAC tumor expression sets was performed. In an orthotopic tumor model, short hairpin RNA mediated PAR1 (shPAR1) knockdown cells derived from p48-CRE/LSL-KRAS/p53flox/flox mice (KP cells) and Panc02 cells were used. Additionally, gene set enrichment analysis was done for EMT signatures on PDAC tumor and pancreatic cancer cell lines. Furthermore, in vitro migratory capacity and mRNA levels for emerging mesenchymal signatures were analyzed in PAR1 knockdown PANC-1 cell line. Results: PAR1 expression does not associate with the overall survival of PDAC patients. However, tumor cell-specific PAR1 silencing potentiates pancreatic tumor growth but decreases metastatic potential in subsequent murine orthotopic pancreatic cancer model. Further analysis of PAR1 expression in PDAC tumors and pancreatic cancer cell lines show positive correlation with mesenchymal signatures and epithelial to mesenchymal transition genes. Indeed, PAR1 knockdown results in well-differentiated pancreatic tumors in vivo, with enhanced epithelial characteristics both in vitro and in vivo. Furthermore, decreased PAR1 activity decreases migratory capacity and in vitro metastatic potential in vivo. Conclusion: Our results suggest that growth promoting effects of PAR1 in stromal cells are counterbalanced by the growth inhibitory contributions of PAR1 in tumor cells. Overall, tumor cell PAR1 is linked to the maintenance of a mesenchymal-like state and silencing PAR1 in this setup results in an increased epithelial phenotype of cancer cells with an increased proliferative index but a decreased metastatic potential. Citation Format: Cansu Tekin, Kun Shi, Arnold Spek, Maarten F. Bijlsma. PAR1 signaling on tumor cells limits tumor growth by maintaining a mesenchymal phenotype in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5225.

Abstract 4103: Utility of multispectral optoacoustic tomography in imaging pancreatic tumors using a uPA-probe

Abstract Background: Pancreatic cancer has the lowest 5-year survival rate of all cancer types. Current methods of pancreatic cancer screening, diagnosis and treatment have failed to improve outcome in the last few decades. Potential explanation for this failure may be explained by the hypovascularized nature of pancreatic cancer, making conventional chemotherapy and imaging modality suboptimal. There is a potential for improved imaging using a new imaging modality, multispectral optoacoustic tomography (MSOT). We hypothesize that a using urokinase plasminogen activator (uPA) contrast agent while using MSOT imaging would improve identification of orthotopic pancreatic cancer in xenografts. Methods: Expression of uPA receptor (uPAR) were evaluated in pancreatic tumor cell lines, Panc1, S2CP9, MiaPaca-2 and S2VP10 using western blot. A uPA targeted contrast agent was created using standard bioconjugation methods with the Hilite 750 near infrared (NIR) dye. Five SCID mice were orthotopically implanted with S2CP9 (1.5 x 105) and 5 additional SCID mice were implanted with MiaPaCa2 (2.0 x 106) pancreatic tumor cells. When tumor size reached 3mm, 200µL of 100 nM uPA-750 probe or 750 dye alone was injected into mice. Biodistribution and accumulation of the uPA-750 probe was visualized using MSOT imaged at 2-hour intervals for 8 hours and at 24 hours. Accumulation of uPA-750 probe was evaluated in the tumor, liver, and kidney using NIR fluorescent imaging. Results: All pancreatic cancer cell line expressed uPAR with the highest in S2CP9 cells (3.0x), S2VP10 (2.5x), Panc1 (1.77x) and MiaPaca-2 (1.3x). In vivo, peak intensity of uPA-750 probe was successfully detected using MSOT at 4 hours, within the pancreas tumor in slices from 37mm-41mm. uPA-750 probe was undetectable within the tumor after 8 hours. Using ex vivo NIR fluorescence imaging, uPA-probe signal was detected only within the pancreatic tumor, however, no signal was detected in the liver or kidney. Conclusion: This study demonstrated MSOT imaging using uPA-probe as a contract agent may lead to improved pancreatic cancer detection which may lead to improvement in overall outcome. Citation Format: Akiko Chiba, Abhilash Samykutty, Mary Smith, Lacey McNally. Utility of multispectral optoacoustic tomography in imaging pancreatic tumors using a uPA-probe [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4103.

MRI-based high-precision irradiation in an orthotopic pancreatic tumor mouse model : Atreatment planning study.

Recently, imaging and high-precision irradiation devices for preclinical tumor models have been developed. Image-guided radiation therapy (IGRT) including innovative treatment planning techniques comparable to patient treatment can be achieved in atranslational context. The study aims to evaluate magnetic resonance imaging/computed tomography (MRI/CT)-based treatment planning with different treatment techniques for high-precision radiation therapy (RT). In an orthotopic pancreatic cancer model, MRI/CT-based radiation treatment planning was established. Three irradiation techniques (rotational, 3D multifield, stereotactic) were performed with the SARRP system (Small Animal Radiation Research Platform, Xstrahl Ltd., Camberley, UK). Dose distributions in gross tumor volume (GTV) and organs at risk (OAR) were analyzed for each treatment setting. MRI with high soft tissue contrast improved imaging of GTV and OARs. Therefore MRI-based treatment planning enables precise contouring of GTV and OARs, thus, providing aperfect basis for an improved dose distribution and coverage of the GTV for all advanced radiation techniques. An MRI/CT-based treatment planning for high-precision IGRT using different techniques was established in an orthotopic pancreatic tumor model. Advanced radiation techniques allow considering perfect coverage of GTV and sparing of OARs in the preclinical setting and reflect clinical treatment plans of pancreatic cancer patients.

An Innovation for Treating Orthotopic Pancreatic Cancer by Preoperative Screening and Imaging-Guided Surgery.

Pancreatic cancer is still associated with a poor outcome and low patient quality of life, which are mainly attributed to the late detection and requirement of distal pancreatectomy with extended resection of pancreatic tumors. Therefore, novel strategies for early screening and precise tumor resection are urgently needed. In this study, we evaluated the feasibility of a low-density lipoprotein receptor (LDLR)-targeted small-molecule contrast agent (peptide-22-Cy7) for early screening with photoacoustic tomography and near-infrared (NIR) imaging as guided surgical navigation to achieve precise resection. Normal pancreatic cells (HPDE6-C7) and cancer cells (PANC-1) were respectively used in the in vitro targeting evaluations. The ability of peptide-22-Cy7 for preoperative in vivo pancreatic tumor detection was investigated in a mouse orthotopic pancreatic cancer model (n = 10) using photoacoustic tomography; 18 tumor-bearing mice were further divided into three groups for different treatments. After intravenous injection of peptide-22-Cy7, surgical navigation was conducted through laparotomy. Histopathological analysis was used to further confirm the tumor area and the state of surgical margins. Flow cytometry demonstrated that peptide-22 is highly specific to pancreatic cancer cells, with a fluorescence intensity of approximately 87.3%. Orthotopic pancreatic tumors with a size of 4mm could be accurately detected by photoacoustic tomography. Surgical navigation effectively achieved R0 resection and minimized the range of resection, which led to increased body weight of the mice following surgery. Overall, our newly developed targeted contrast agent facilitated the accurate positioning and resection of pancreatic tumors. Photoacoustic tomography and optical imaging-guided surgical navigation may be a novel direction for improving the survival, quality of life, and disease management of pancreatic cancer patients.