The biological underpinnings of therapeutic resistance in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related mortality in the United States and has only recently achieved a 5-yr survival rate of 10%. This dismal prognosis reflects the remarkable capacity of PDAC to effectively adapt to and resist therapeutic intervention. In this review, we discuss recent advances in our understanding of the biological underpinnings of PDAC and their implications as targetable vulnerabilities in this highly lethal disease.

Reprogramming tumor immune microenvironment by milbemycin oxime results in pancreatic tumor growth suppression and enhanced anti-PD-1 efficacy.

Pancreatic ductal adenocarcinoma (PDAC) has a survival rate of 12%, and multiple clinical trials testing anti-PD-1 therapies against PDAC have failed, suggesting a need for a novel therapeutic strategy. In this study, we evaluated the potential of milbemycin oxime (MBO), an antiparasitic compound, as an immunomodulatory agent in PDAC. Our results show that MBO inhibited the growth of multiple PDAC cell lines by inducing apoptosis. In vivo studies showed that the oral administration of 5 mg/kg MBO inhibited PDAC tumor growth in both subcutaneous and orthotopic models by 49% and 56%, respectively. Additionally, MBO treatment significantly increased the survival of tumor-bearing mice by 27 days as compared to the control group. Interestingly, tumors from MBO-treated mice had increased infiltration of CD8+ T cells. Notably, depletion of CD8+ T cells significantly reduced the anti-tumor efficacy of MBO in mice. Furthermore, MBO significantly augmented the efficacy of anti-PD-1 therapy, and the combination treatment resulted in a greater proportion of active cytotoxic T cells within the tumor microenvironment. MBO was safe and well tolerated in all our preclinical toxicological studies. Overall, our study provides a new direction for the use of MBO against PDAC and highlights the potential of repurposing MBO for enhancing anti-PD-1 immunotherapy.

An oncolytic system produces oxygen selectively in pancreatic tumor cells to alleviate hypoxia and improve immune activation.

INTRODUCTION: Hypoxia is one of the important reasons for the poor therapeutic efficacy of current pancreatic cancer treatment, and the dense stroma of pancreatic cancer restricts the diffusion of oxygen within the tumor. METHODS: A responsive oxygen-self-supplying adv-miRT-CAT-KR (adv-MCK) cascade reaction system to improve hypoxia in pancreatic cancer is constructed. We utilized various experiments at multiple levels (cells, organoids, in vivo) to investigate its effect on pancreatic cancer and analyzed the role of immune microenvironment changes in it through high-throughput sequencing. RESULTS: The adv-MCK system is an oncolytic adenovirus system expressing three special components of genes. The microRNA (miRNA) targets (miRTs) enable adv-MCK to selectively replicate in pancreatic cancer cells. Catalase catalyzes the overexpressed hydrogen peroxide in pancreatic cancer cells to generate endogenous oxygen, which is catalyzed by killerRed to generate singlet oxygen (1O2) and further to enhance the oncolytic effect. Meanwhile, the adv-MCK system can specifically improve hypoxia in pancreatic cancer, exert antitumor effects in combination with photodynamic therapy, and activate antitumor immunity, especially by increasing the level of γδ T cells in the tumor microenvironment. CONCLUSION: The responsive oxygen-self-supplying adv-MCK cascade reaction system combined with photodynamic therapy can improve the hypoxic microenvironment of pancreatic cancer and enhance antitumor immunity, which provides a promising alternative treatment strategy for pancreatic cancer.

A novel likely pathogenetic variant p.(Cys235Arg) of the MEN1 gene in multiple endocrine neoplasia type 1 with multifocal glucagonomas.

PURPOSE: Multiple endocrine neoplasia type 1 (MEN1) is a hereditary endocrine syndrome caused by pathogenic variants in MEN1 tumor suppressor gene. Diagnosis is commonly based on clinical criteria and confirmed by genetic testing. The objective of the present study was to report on a MEN1 case characterized by multiple pancreatic glucagonomas, with particular concern on the possible predisposing genetic defects. METHODS: While conducting an extensive review of the most recent scientific evidence on the unusual glucagonoma familial forms, we analyzed the MEN1 gene in a 35-year-old female with MEN1, as well as her son and daughter, using Sanger and next-generation sequencing (NGS) approaches. We additionally explored the functional and structural consequences of the identified variant using in silico analyses. RESULTS: NGS did not show any known pathogenic variant in the tested regions. However, a new non-conservative variant in exon 4 of MEN1 gene was found in heterozygosity in the patient and in her daughter, resulting in an amino acid substitution from hydrophobic cysteine to hydrophilic arginine at c.703T > C, p.(Cys235Arg). This variant is absent from populations databases and was never reported in full papers: its characteristics, together with the high specificity of the patient's clinical phenotype, pointed toward a possible causative role. CONCLUSION: Our findings confirm the need for careful genetic analysis of patients with MEN1 and establish a likely pathogenic role for the new p.(Cys235Arg) variant, at least in the rare subset of MEN1 associated with glucagonomas.

Scope transition and early arterial inflow control provide safe and comfortable dissection in robotic distal pancreatectomy.

PURPOSE: We describe details and outcomes of a novel technique for optimizing the surgical field during robotic distal pancreatectomy (RDP) for distal pancreatic lesions, which has become common with potential advantages over laparoscopic surgery. METHODS: For suprapancreatic lymph node dissection and splenic artery ligation, we used the basic center position with a scope through the midline port. During manipulation of the perisplenic area, the left position was used by moving the scope to the left medial side. The left lateral position is optionally used by moving the scope to the left lateral port when scope access to the perisplenic area is difficult. In addition, early splenic artery clipping and short gastric artery dissection for inflow block were performed to minimize bleeding around the spleen. We evaluated retrospectively the surgical outcomes of our method using a scoring system that allocated one point for blood inflow control and one point for optimizing the surgical view in the left position. RESULTS: We analyzed 34 patients who underwent RDP or R-radical antegrade modular pancreatosplenectomy (RAMPS). The left position was applied in 14 patients, and the left lateral position was applied in 6. Based on the scoring system, only the 0-point group (n = 8) had four bleeding cases (50%) with splenic injury or blood pooling; the other 1-point or 2-point groups (n = 13, respectively) had no bleeding cases (p = 0.0046). CONCLUSION: Optimization of the surgical field using scope transition and inflow control ensured safe dissection during RDP.

The Wdr5-H3K4me3 Epigenetic Axis Regulates Pancreatic Tumor Immunogenicity and Immune Suppression.

The WDR5/MLL1-H3K4me3 epigenetic axis is often activated in both tumor cells and tumor-infiltrating immune cells to drive various cellular responses in the tumor microenvironment and has been extensively studied in hematopoietic cancer, but its respective functions in tumor cells and immune cells in the context of tumor growth regulation of solid tumor is still incompletely understood. We report here that WDR5 exhibits a higher expression level in human pancreatic tumor tissues compared with adjacent normal pancreas. Moreover, WDR5 expression is negatively correlated with patients' response to chemotherapy or immunotherapy in human colon cancer and melanoma. However, WDR5 expression is positively correlated with the HLA level in human cancer cells, and H3K4me3 enrichment is observed at the promoter region of the HLA-A, HLA-B, and HLA-C genes in pancreatic cancer cells. Using mouse tumor cell lines and in vivo tumor models, we determined that WDR5 deficiency or inhibition significantly represses MHC I expression in vitro and in vivo in pancreatic tumor cells. Mechanistically, we determine that WDR5 deficiency inhibits H3K4me3 deposition at the MHC I (H2K) promoter region to repress MHC I (H2K) transcription. On the other hand, WDR5 depletion leads to the effective downregulation of immune checkpoints and immunosuppressive cytokines, including TGFß and IL6, in the pancreatic tumor microenvironments. Our data determine that WDR5 not only regulates tumor cell immunogenicity to suppress tumor growth but also activates immune suppressive pathways to promote tumor immune evasion. Selective activation of the WDR5-MHC I pathway and/or selective inhibition of the WDR5-immune checkpoint and WDR5-cytokine pathways should be considered in WDR5-based epigenetic cancer immunotherapy.

Endoscopic ultrasound fine-needle biopsy to assess DAXX/ATRX expression and alternative lengthening of telomeres status in non-functional pancreatic neuroendocrine tumors.

BACKGROUND/OBJECTIVES: Death domain-associated protein (DAXX) and/or α-thalassemia/mental retardation X-linked (ATRX) chromatin remodeling genes mutations and alternative lengthening of telomeres (ALT) activation are associated with more aggressive behavior of non-functional pancreatic neuroendocrine tumors (NF-PanNETs). We aimed to evaluate the reliability of such markers on endoscopic-ultrasound fine-needle biopsy (EUS-FNB) specimens. METHODS: Patients who underwent EUS-FNB and subsequent surgical resection for PanNETs between January 2017 and December 2019 were retrospectively identified. Immunohistochemistry (IHC) to evaluate DAXX/ATRX expression and fluorescence in situ hybridization (FISH) for ALT status were performed. Primary outcome was the concordance rate of markers expression between EUS-FNB and surgical specimens. Secondary aims were association between markers and lesion aggressiveness, their diagnostic performance in predicting aggressiveness, and agreement of preoperative and post-surgical Ki67-based grading. RESULTS: Forty-one NF-PanNETs (mean diameter 36.1 ± 26.5 mm) were included. Twenty-four showed features of lesion aggressiveness. Concordance of expressions of DAXX, ATRX, and ALT status between EUS-FNB and surgical specimens were 95.1% (κ = 0.828; p < 0.001), 92.7% (κ = 0.626; p < 0.001), and 100% (κ = 1; p < 0.001), respectively. DAXX/ATRX loss and ALT-positivity were significantly (p < 0.05) associated with metastatic lymphnodes and lymphovascular invasion. The combination of all tumor markers (DAXX/ATRX loss + ALT-positivity + grade 2) reached an accuracy of 73.2% (95%CI 57.1-85.8) in identifying aggressive lesions. Pre- and post-operative ki-67-based grading was concordant in 80.5% of cases (k = 0.573; p < 0.001). CONCLUSION: DAXX/ATRX expression and ALT status can be accurately evaluated in a preoperative setting on EUS-FNB samples, potentially improving the identification of patients with increased risk and poorer prognosis.

Surgical outcome and prognosis of pediatric solid-pseudopapillary neoplasm.

BACKGROUND: The aim of this study was to clarify the characteristics and outcomes of pediatric patients with solid pseudopapillary neoplasms (SPNs) who underwent pancreatectomy. METHODS: Pediatric patients with SPNs who underwent pancreatectomy at our institution between 1995 and 2020 were included in the study. RESULTS: During the period under review, 12 patients underwent pancreatectomy for SPNs (median age: 10 years; range: 6-15 years). The surgical procedures included pancreatoduodenectomy (n = 2; 16.6%), distal pancreatectomy (n = 3; 25%), and enucleation (n = 7; 58.3%). The most common postoperative complication was postoperative pancreatic fistula (n = 6; 50%). Patients who underwent enucleation tended to have higher postoperative complication rates compared with those who underwent other procedures. All patients were alive without recurrence at the end of the study period. CONCLUSIONS: SPN is associated with a good prognosis, regardless of the surgical procedure. If surgeons select enucleation for pediatric SPNs, they should bear in mind that it is associated with a higher complication rate.

Evaluating motion of pancreatic tumors and anatomical surrogates using cine MRI in 0.35T MRgRT under free breathing conditions.

Treatment tolerability is a significant limitation to pancreatic cancer treatment with radiotherapy due to proximity to highly radiosensitive organs and respiratory motion necessitating expanded target margins. Further, pancreatic tumors are difficult to visualize on conventional radiotherapy systems. Surrogates are often used to locate the tumor but are often inconsistent and do not provide strong positional relations throughout the respiratory cycle. This work utilizes a retrospective dataset of 45 pancreatic cancer patients treated on an MR-Linac system with cine MRI acquired for real-time target tracking. We investigated intra-fraction motion of tumors and two abdominal surrogates, leading to prediction models between the tumor and surrogate. Patient specific motion evaluation and prediction models were generated from 225 cine MRI series acquired during treatment. Tumor contours were used to evaluate the pancreatic tumor motion. Linear regression and principal component analysis (PCA) based models were used to predict tumor position from the anterior-posterior (AP) motion of the abdominal surface, the superior-inferior (SI) motion of the diaphragm, or a combination. Models were evaluated using mean squared error (MSE) and mean absolute error (MAE). Contour analysis showed the average pancreatic tumor motion range was 7.4 ± 2.7 mm and 14.9 ± 5.8 mm in the AP and SI directions, respectively. The PCA model had MSE of 1.4 mm2 and 0.6 mm2 , for the SI and AP directions, respectively, with both surrogates as inputs for the models. When only the abdomen surrogate was used, MSE was 1.3 mm2 and 0.4 mm2 in the SI and AP directions, while it was 0.4 mm2 and 1.3 mm2 when only the diaphragm surrogate was used. We evaluated intra-fraction pancreatic tumor motion and demonstrated prediction models between the tumor and surrogate. The models calculated the pancreatic tumor position from diaphragm, abdominal, or both contours within standard pancreatic cancer target margin, and the process could be applied to other disease sites in the abdominothoracic cavity.

Synthesis and In Vitro Evaluation as Potential Anticancer and Antioxidant Agents of Diphenylamine-Pyrrolidin-2-one-Hydrazone Derivatives.

The title compounds were synthesized by the reaction of 5-oxo-1-(4-(phenylamino)phenyl)pyrrolidine-3-carbohydrazide with various aldehydes bearing aromatic and heterocyclic moieties and acetophenones, and their cytotoxicity was tested via MTT assay against human triple-negative breast cancer MDA-MB-231, human melanoma IGR39, human pancreatic carcinoma Panc-1, and prostate cancer cell line PPC-1. Furthermore, the selectivity of compounds towards cancer cells compared to fibroblasts was also investigated. Four compounds were identified as the most promising anticancer agents out of a series of pyrrolidinone-hydrazone derivatives bearing a diphenylamine moiety. These compounds were most selective against the prostate cancer cell line PPC-1 and the melanoma cell lines IGR39, with EC50 values in the range of 2.5-20.2 µM against these cell lines. In general, the compounds were less active against triple-negative breast cancer MDA-MB-231 cell line, and none of them showed an inhibitory effect on the migration of these cells. In the 'wound healing' assay, N'-((5-nitrothiophen-2-yl)methylene)-5-oxo-1-(4-(phenylamino)phenyl)pyrrolidine-3-carbohydrazide was identified as the most promising derivative that could be further developed as an antimetastatic agent. N'-(5-chloro- and N'-(3,4-dichlorobenzylidene)-5-oxo-1-(4-(phenylamino)phenyl)pyrrolidine-3-carbohydrazides most efficiently reduced the cell viability in IGR39 cell spheroids, while there was no effect of the investigated pyrrolidinone-hydrazone derivatives on PPC-1 3D cell cultures. Antioxidant activity determined via FRAP assay of N'-(1-(4-aminophenyl)ethylidene)-5-oxo-1-(4-(phenylamino)phenyl)pyrrolidine-3-carbohydrazide was 1.2 times higher than that of protocatechuic acid.

CT classification model of pancreatic serous cystic neoplasm and mucinous cystic neoplasm based on deep transfer learning.

BACKGROUND: Pancreatic cancer is a highly lethal disease. The preoperative distinction between pancreatic serous cystic neoplasm (SCN) and mucinous cystic neoplasm (MCN) remains a clinical challenge. OBJECTIVE: The goal of this study is to provide clinicians with supportive advice and avoid overtreatment by constructing a convolutional neural network (CNN) classifier to automatically identify pancreatic cancer using computed tomography (CT) images. METHODS: We construct a CNN model using a dataset of 6,173 CT images obtained from 107 pathologically confirmed pancreatic cancer patients at Shanghai Changhai Hospital from January 2017 to February 2022. We divide CT slices into three categories namely, SCN, MCN, and no tumor, to train the DenseNet201-based CNN model with multi-head spatial attention mechanism (MSAM-DenseNet201). The attention module enhances the network's attention to local features and effectively improves the network performance. The trained model is applied to process all CT image slices and finally realize the two categories classification of MCN and SCN patients through a joint voting strategy. RESULTS: Using a 10-fold cross validation method, this new MSAM-DenseNet201 model achieves a classification accuracy of 92.52%, a precision of 92.16%, a sensitivity of 92.16%, and a specificity of 92.86%, respectively. CONCLUSIONS: This study demonstrates the feasibility of using a deep learning network or classification model to help diagnose MCN and SCN cases. This, the new method has great potential for developing new computer-aided diagnosis systems and applying in future clinical practice.

A dopamine antagonist, domperidone enhances the replication of an oncolytic adenovirus in human tumour cells.

Oncolytic adenoviruses (OAds) have attracted much attention as novel anticancer agents. Numerous studies have examined the antitumour effects of combinational use of an OAd and anticancer agents; however, few chemical compounds enhancing OAd infection have been reported. In this study, we screened a food and drug administration (FDA)-approved drug library containing 1134 small chemical compounds to identify chemical compounds that enhance OAd replication in human tumour cells. We found that domperidone, a dopamine D2 receptor antagonist, significantly enhanced the replication of an OAd in human tumour cells, including human pancreatic tumour cells, by two-fivefold, resulting in improvement of OAd-mediated tumour cell killing activities. The E1A mRNA levels were significantly increased in domperidone-pre-treated cells following OAd infection, which contributed to the promotion of OAd replication. However, mRNA levels of the dopamine D2 receptor (DRD2), which is known to be a target molecule of domperidone, were undetectable in most of the tumour cells by real-time reverse transcription (RT)-PCR analysis, indicating that domperidone promoted OAd replication by acting on a molecule other than DRD2. This study provides important clues for the improvement of OAd-mediated cancer therapy.

Multivalent γ-PGA-Exendin-4 Conjugates to Target Pancreatic ß-Cells.

Targeting of glucagon-like peptide 1 receptor (GLP-1R), expressed on the surface of pancreatic ß-cells, is of great interest for the development of advanced therapies for diabetes and diagnostics for insulinoma. We report the conjugation of exendin-4 (Ex-4), an approved drug to treat type 2 diabetes, to poly-γ-glutamic acid (γ-PGA) to obtain more stable and effective GLP-1R ligands. Exendin-4 modified at Lysine-27 with PEG4-maleimide was conjugated to γ-PGA functionalized with furan, in different molar ratios, exploiting a chemoselective Diels-Alder cycloaddition. The γ-PGA presenting the highest number of conjugated Ex-4 molecules (average 120 per polymeric chain) showed a double affinity towards GLP-1R with respect to exendin per se, paving the way to improved therapeutic and diagnostic applications.

IGF1 receptor-targeted black TiO2 nanoprobes for MRI-guided synergetic photothermal-chemotherapy in drug resistant pancreatic tumor.

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest malignant tumors with features of matrix barrier caused poor drug permeability, and susceptibility to drug resistance. Herein, a PDAC and its stromal cell dual-targeted photothermal-chemotherapy strategy is explored to loosen the matrix and reverse drug resistance. To achieve this goal, black TiO2-Gd nanocomposites were conjugated with insulin like growth factor 1 (IGF1), and loaded with gemcitabine (GEM) to construct bTiO2-Gd-IGF1-GEM nanoprobes. In vitro results show that under 808 nm near-infrared irradiation, killing effect of the nanoprobes on drug-resistant MIA PaCa-2 cell is 3.3 times than that of GEM alone. In vivo experiments indicate the synergetic photothermal-chemotherapy not only loosens fibrous matrix of pancreatic tumor model, but also dramatically inhibits tumor growth, and almost completely eradicates the tumor after 12 days of treatment. In addition, relaxation rate of the nanoprobes is 8.2 times than commercial contrast agent Magnevist, therefore boosts the signal of magnetic resonance imaging in pancreatic tumor. In conclusion, our results reinforce that the prepared nanoprobes are promising to break matrix barrier and overcome drug resistance in PDAC.

Needle tract seeding after endoscopic ultrasound-guided tissue acquisition of pancreatic tumors: A nationwide survey in Japan.

OBJECTIVES: Endoscopic ultrasound-guided tissue acquisition (EUS-TA) plays a crucial role in the diagnosis of pancreatic tumors. The present study aimed to investigate the current status of needle tract seeding (NTS) after EUS-TA of pancreatic tumors based on a nationwide survey in Japan. METHODS: Patients who underwent surgical resection of primary pancreatic tumors after EUS-TA performed between April 2010 and March 2018 were surveyed. The incidence rates of NTS were determined, and compared in patients with pancreatic ductal adenocarcinomas (PDACs) and other tumors, and in patients who underwent transgastric and transduodenal EUS-TA of PDACs. The detailed features and prognosis of patients with NTS were also assessed. RESULTS: A total of 12,109 patients underwent surgical resection of primary pancreatic tumors after EUS-TA. The overall incidence rate of NTS was 0.330%, and the NTS rate was significantly higher in patients with PDAC than in those with other tumors (0.409% vs. 0.071%, P=0.004). NTS was observed in 0.857% of patients who underwent transgastric EUS-TA, but in none of those who underwent transduodenal EUS-TA. Of the patients with NTS of PDACs, the median time from EUS-TA to occurrence of NTS and median patient survival were 19.3 and 44.7 months, respectively, with 97.4% of NTS located in the gastric wall and 65.8% of NTS resected. The patient survival was significantly longer in patients who underwent NTS resection than in those without NTS resection (P=0.037). CONCLUSIONS: NTS appeared only after transgastric not after transduodenal EUS-TA. Careful follow-up provides an opportunity to remove localized NTS lesions by gastrectomy.

Management of non-functional pancreatic neuroendocrine tumors by endoscopic ultrasound-guided radiofrequency ablation: Retrospective study in two tertiary centers.

BACKGROUND: Recently, there has been growing interest in investigating endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) for the management of small non-functional pancreatic neuroendocrine tumors (nf pNETs). PATIENTS AND METHODS: A bicentric retrospective study was performed that included patients with histologically confirmed nf pNETs who were consecutively treated by EUS-RFA between December 2015 and March 2021 at two tertiary referral centers. RESULTS: In 27 patients (mean age 65.0 years, 52% male), EUS-RFA was successfully performed. All patients had sporadic G1 lesions (mean size 14.0 ± 4.6 mm, 7% uncinated process, 22% head, 11% body, 19% body/tail junction, and 41% tail). Overall, 9/27 lesions (33%) were cystic. The mean hospital stay was 3.2 days. Complete treatment response was confirmed in 25/27 patients (93%) on cross-sectional imaging (mean follow-up 15.7 ± 12.2 months, range 2-41 months). Two patients had two EUS-RFA sessions until complete necrosis was observed. Periprocedural acute pancreatitis occurred in 4/27 (14.8%), three of them were treated by endoscopic cystogastrostomy (11.1%). One patient underwent secondary surgery. The histopathology of the resected specimen revealed 3 mm of residual tumor tissue. CONCLUSION: EUS-RFA seems to be a promising treatment strategy for the management of small nf pNETs with excellent efficacy. Further evidence focusing on long-term survival, safety profile and recurrence is needed.

Applying a radiomics-based CAD scheme to classify between malignant and benign pancreatic tumors using CT images.

BACKGROUND: Pancreatic cancer is one of the most aggressive cancers with approximate 10% five-year survival rate. To reduce mortality rate, accurate detection and diagnose of suspicious pancreatic tumors at an early stage plays an important role. OBJECTIVE: To develop and test a new radiomics-based computer-aided diagnosis (CAD) scheme of computed tomography (CT) images to detect and classify suspicious pancreatic tumors. METHODS: A retrospective dataset consisting of 77 patients who had suspicious pancreatic tumors detected on CT images was assembled in which 33 tumors are malignant. A CAD scheme was developed using the following 5 steps namely, (1) apply an image pre-processing algorithm to filter and reduce image noise, (2) use a deep learning model to detect and segment pancreas region, (3) apply a modified region growing algorithm to segment tumor region, (4) compute and select optimal radiomics features, and (5) train and test a support vector machine (SVM) model to classify the detected pancreatic tumor using a leave-one-case-out cross-validation method. RESULTS: By using the area under receiver operating characteristic (ROC) curve (AUC) as an evaluation index, SVM model yields AUC = 0.750 with 95% confidence interval [0.624, 0.885] to classify pancreatic tumors. CONCLUSIONS: Study results indicate that radiomics features computed from CT images contain useful information associated with risk of tumor malignancy. This study also built a foundation to support further effort to develop and optimize CAD schemes with more advanced image processing and machine learning methods to more accurately and robustly detect and classify pancreatic tumors in future.

Role of biliary stent and neoadjuvant chemotherapy in the pancreatic tumor microbiome.

BACKGROUND: Intra-tumor microbiota have been implicated in pancreatic ductal adenocarcinoma (PDAC) development, treatment response and post-treatment survivorship. Moreover, therapeutic interventions targeting microbiota may improve the response to chemotherapy and immunotherapy, further emphasizing the critical need to understand the origins of and growth of bacteria within the pancreatic tumor microenvironment. Here, we studied the role of several clinical factors on the bacterial colonization of PDAC. RESULTS: We obtained matched tumor and normal pancreatic tissue specimens from 27 patients who had undergone surgical resection for PDAC between 2011 and 2015 from the University of Minnesota Biological Materials Procurement Network (BioNet). We found that 26 (48%) out of 54 pancreatic tissue samples harbored detectable bacterial communities using real-time PCR targeting the 16S rRNA gene. Bacterial colonization was detected significantly more frequently in samples from patients who had pancreatic head tumors, underwent Whipple procedure, or had preoperative biliary stent placement. There was also a significantly greater relative abundance of microbiota from the family Enterobacteriaceae among samples from patients who underwent biliary stent placement or neoadjuvant treatment with a combination of Gemcitabine and Paclitaxel. CONCLUSIONS: These findings suggest that biliary stent placement and neoadjuvant chemotherapy are associated with specific alterations that promote the infiltration and growth of intra-tumor bacteria in the setting of PDAC. Further studies exploring whether specific bacterial communities could contribute to increased chemoresistance will be essential for optimizing medical therapies in the future.

CD47 expression and CD163+ macrophages correlated with prognosis of pancreatic neuroendocrine tumor.

BACKGROUND: Recent studies have suggested the important roles of CD47 and tumor-associated macrophages in the prognosis and immunotherapy of various human malignancies. However, the clinical significance of CD47 expression and CD163+ TAMs in pancreatic neuroendocrine tumor (PanNET) remains unclear. METHODS: In this study, 47 well-differentiated PanNET resection specimens were collected. CD47 expression and CD163+ macrophages were evaluated using immunohistochemistry and correlated with clinicopathologic properties. RESULTS: Positive CD47 staining was seen in all PanNETs as well as adjacent normal islets. Compared to normal islets, CD47 overexpressed in PanNETs (p = 0.0015). In the cohort, lymph node metastasis (LNM), lymphovascular invasion (LVI), and perineural invasion (PNI) were found in 36.2, 59.6, and 48.9% of the cases, respectively. Interestingly, PanNETs with LNM, LVI, or PNI had significantly lower H-score of CD47 than those without LNM (p = 0.035), LVI (p = 0.0005), or PNI (p = 0.0035). PanNETs in patients with disease progression (recurrence/death) also showed a significantly lower expression of CD47 than those without progression (p = 0.022). In contrast, CD163+ macrophage counts were significantly higher in cases with LNM, LVI, and PNI. CONCLUSIONS: Our data suggest relative low CD47 expression and high CD163+ TAMs may act as indicators for poor prognosis of PanNETs.

Three-Dimensional Primary Cell Culture: A Novel Preclinical Model for Pancreatic Neuroendocrine Tumors.

Molecular mechanisms underlying the development and progression of pancreatic neuroendocrine tumors (PanNETs) are still insufficiently understood. Efficacy of currently approved PanNET therapies is limited. While novel treatment options are being developed, patient stratification permitting more personalized treatment selection in PanNET is yet not feasible since no predictive markers are established. The lack of representative in vitro and in vivo models as well as the rarity and heterogeneity of PanNET are prevailing reasons for this. In this study, we describe an in vitro 3-dimensional (3-D) human primary PanNET culture system as a novel preclinical model for more personalized therapy selection. We present a screening platform allowing multicenter sample collection and drug screening in 3-D cultures of human primary PanNET cells. We demonstrate that primary cells isolated from PanNET patients and cultured in vitro form islet-like tumoroids. Islet-like tumoroids retain a neuroendocrine phenotype and are viable for at least 2 weeks in culture with a high success rate (86%). Viability can be monitored continuously allowing for a per-well normalization. In a proof-of-concept study, islet-like tumoroids were screened with three clinically approved therapies for PanNET: sunitinib, everolimus and temozolomide. Islet-like tumoroids display varying in vitro response profiles to distinct therapeutic regimes. Treatment response of islet-like tumoroids differs also between patient samples. We believe that the presented human PanNET screening platform is suitable for personalized drug testing in a larger patient cohort, and a broader application will help in identifying novel markers predicting treatment response and in refining PanNET therapy.