The Cellular Origins of Cancer-Associated Fibroblasts and Their Opposing Contributions to Pancreatic Cancer Growth

Pancreatic tumors are known to harbor an abundant and highly desmoplastic stroma. Among the various cell types that reside within tumor stroma, cancer-associated fibroblasts (CAFs) have gained a lot of attention in the cancer field due to their contributions to carcinogenesis and tumor architecture. These cells are not a homogeneous population, but have been shown to have different origins, phenotypes, and contributions. In pancreatic tumors, CAFs generally emerge through the activation and/or recruitment of various cell types, most notably resident fibroblasts, pancreatic stellate cells (PSCs), and tumor-infiltrating mesenchymal stem cells (MSCs). In recent years, single cell transcriptomic studies allowed the identification of distinct CAF populations in pancreatic tumors. Nonetheless, the exact sources and functions of those different CAF phenotypes remain to be fully understood. Considering the importance of stromal cells in pancreatic cancer, many novel approaches have aimed at targeting the stroma but current stroma-targeting therapies have yielded subpar results, which may be attributed to heterogeneity in the fibroblast population. Thus, fully understanding the roles of different subsets of CAFs within the stroma, and the cellular dynamics at play that contribute to heterogeneity in CAF subsets may be essential for the design of novel therapies and improving clinical outcomes. Fortunately, recent advances in technologies such as microfluidics and bio-printing have made it possible to establish more advanced ex vivo models that will likely prove useful. In this review, we will present the different roles of stromal cells in pancreatic cancer, focusing on CAF origin as a source of heterogeneity, and the role this may play in therapy failure. We will discuss preclinical models that could be of benefit to the field and that may contribute to further clinical development.

Abstract LB-239: Co-expression analysis reveals tumor biology and prognostic biomarkers in pancreatic ductal adenocarcinoma

Despite extensive biological and clinical studies, including comprehensive profiling using genomics and transcriptomics efforts, pancreatic ductal adenocarcinoma (PDAC) remains a devastating disease, with poor survival and no effective therapies to date. Development of new tools and experimental methods are driven by the urge of identification of better sensitive and specific biomarkers for this disease. In recent years, multiple statistical methods and freely available tools have been developed and can extrapolate important features in high-throughput data, e.g. pinpointing genes associated with clinical parameters such as cancer status or patient survival. In this context, network topology based on co-expression has extensively been used to identify subsets of gene-disease relations. Correlation networks are emerging as a powerful approach to infer tumor biology from -omics data and to prioritize candidate genes as biomarkers or drug targets. In this study, we applied a weighted co-expression analysis to the proteome of 20 surgically resected PDAC specimens. Next, modules were associated to clinical end points to underline prognostic markers.This co-expression analysis yielded 12 consensus modules, subsequently analyzed by gene set enrichment analysis (GSEA) to characterize the associated biology. The modules covered a wide range of biological terms, and the most frequently occurring terms were those implicated in metabolic processes in the context of mitochondrial compartment. More specifically, five modules consisted predominantly of immune system and defense and four modules were associated with epithelial to mesenchymal transition processes. Notably, one module enriched for metabolic processes and epithelial-mesenchymal-transition (EMT) was significantly associated with overall survival (p=0.01) and disease-free survival (p = 0.03). The prognostic value of three proteins (SPTBN1, KHSRP and PYGL) belonging to this module was confirmed using immunohistochemistry in a cohort of 82 resected patients. Risk score evaluation of the prognostic signature confirmed the association to OS in multivariate analysis. Finally, immunofluorescence confirmed co-expression of SPTBN1 and KHSRP in Hs766t PDAC cells. Taken together, our results demonstrate that an EMT - metabolic module is associated with prognosis after surgical resection of PDAC patients and the module's proteins SPTBN1, KHSRP and PYGL are potential biomarkers for prognosis. Our results also show that co-expression networks are able to extrapolate tumor-specific biology as well as biological mechanisms empowering prognostic marker discovery, even with a limited number of samples.

Citation Format: Giulia Mantini, Andrea Valles, Tessa Le Large, Mjriam Capula, Niccola Funel, Thang Pham, Sander Piersma, Geert Kazemier, Maarten Bijlsma, Elisa Giovannetti, Connie Jimenez. Co-expression analysis reveals tumor biology and prognostic biomarkers in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-239.

Genetic determinants of telomere length and risk of pancreatic cancer: A PANDoRA study

Telomere deregulation is a hallmark of cancer. Telomere length measured in lymphocytes (LTL) has been shown to be a risk marker for several cancers. For pancreatic ductal adenocarcinoma (PDAC) consensus is lacking whether risk is associated with long or short telomeres. Mendelian randomization approaches have shown that a score built from SNPs associated with LTL could be used as a robust risk marker. We explored this approach in a large scale study within the PANcreatic Disease ReseArch (PANDoRA) consortium. We analyzed 10 SNPs (ZNF676-rs409627, TERT-rs2736100, CTC1-rs3027234, DHX35-rs6028466, PXK-rs6772228, NAF1-rs7675998, ZNF208-rs8105767, OBFC1-rs9420907, ACYP2-rs11125529 and TERC-rs10936599) alone and combined in a LTL genetic score ("teloscore", which explains 2.2% of the telomere variability) in relation to PDAC risk in 2,374 cases and 4,326 controls. We identified several associations with PDAC risk, among which the strongest were with the TERT-rs2736100 SNP (OR = 1.54; 95%CI 1.35-1.76; p = 1.54 × 10-10 ) and a novel one with the NAF1-rs7675998 SNP (OR = 0.80; 95%CI 0.73-0.88; p = 1.87 × 10-6 , ptrend = 3.27 × 10-7 ). The association of short LTL, measured by the teloscore, with PDAC risk reached genome-wide significance (p = 2.98 × 10-9 for highest vs. lowest quintile; p = 1.82 × 10-10 as a continuous variable). In conclusion, we present a novel genome-wide candidate SNP for PDAC risk (TERT-rs2736100), a completely new signal (NAF1-rs7675998) approaching genome-wide significance and we report a strong association between the teloscore and risk of pancreatic cancer, suggesting that telomeres are a potential risk factor for pancreatic cancer.

Association Between Workarounds and Medication Administration Errors in Bar Code-Assisted Medication Administration: Protocol of a Multicenter Study

Background

Information technology-based methods such as bar code-assisted medication administration (BCMA) systems have the potential to reduce medication administration errors (MAEs) in hospitalized patients. In practice, however, systems are often not used as intended, leading to workarounds. Workarounds may result in MAEs that may harm patients.

Objective

The primary aim is to study the association of workarounds with MAEs in the BCMA process. Second, we will determine the frequency and type of workarounds and MAEs and explore the potential risk factors (determinants) for workarounds.

Methods

This is a multicenter prospective study on internal medicine and surgical wards of 4 Dutch hospitals using BCMA systems to administer medication. We will include a total of 6000 individual drug administrations using direct observation to collect data.

Results

The project was funded in 2014 and enrollment was completed at the end of 2016. Data analysis is under way and the first results are expected to be submitted for publication at the end of 2017.

Conclusions

If an association between workarounds and MAEs is established, this information can be used to reduce the frequency of MAEs. Information on determinants of workarounds can aid in a focused approach to reduce workarounds and thus increase patient safety.

Trial Registration

Netherlands Trial Register NTR4355; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4355 (Archived by WebCite at http://www.webcitation.org/6pqTLxc6i).

BAG3 promotes pancreatic ductal adenocarcinoma growth by activating stromal macrophages

The incidence and death rate of pancreatic ductal adenocarcinoma (PDAC) have increased in recent years, therefore the identification of novel targets for treatment is extremely important. Interactions between cancer and stromal cells are critically involved in tumour formation and development of metastasis. Here we report that PDAC cells secrete BAG3, which binds and activates macrophages, inducing their activation and the secretion of PDAC supporting factors. We also identify IFITM-2 as a BAG3 receptor and show that it signals through PI3K and the p38 MAPK pathways. Finally, we show that the use of an anti-BAG3 antibody results in reduced tumour growth and prevents metastasis formation in three different mouse models. In conclusion, we identify a paracrine loop involved in PDAC growth and metastatic spreading, and show that an anti-BAG3 antibody has therapeutic potential.

Abstract 421: The role of the tumor microenvironment of pancreatic cancer to predict treatment outcome

Introduction: Pancreatic ductal adenocarcinoma (PDAC) ranks 4th on the list of cancer-related deaths which is mostly due to therapy resistance. The tumor microenvironment is one of the main hallmarks to contribute to therapy resistance in which tumors are characterized by large amounts of stroma deposition, and hypovascularization. In this study we assess the use of non-invasive functional magnetic resonance imaging (MRI) for characterization of these tumor microenvironment characteristics and its prognostic and predictive role. Diffusion weighted (DWI) MRI and dynamic contrast enhanced (DCE)-MRI provide insight in stromal content and tumor vascularization. Subsequent correlation of imaging with immunohistochemical (IHC) stainings can validate the biological basis of these imaging modalities. Here, we propose a method to correlate functional MRI to corresponding histology derived tissue characteristics.

Methods: Patients suffering from (borderline) resectable PDAC underwent DWI and DCE-MRI on a 3T Philips scanner prior to resection and/or neoadjuvant chemoradiation. DWI data were fitted with the intra voxel incoherent motion model to obtain, among others, the diffusion coefficient D, while DCE-MRI data were fitted according to the extended Tofts model to retrieve the volume transfer constant Ktrans. After resection, the tissue was sectioned in the axial plane and slices where photographed. One slice with evident tumor was selected for whole mount embedding. Whole mount sections were stained for stromal content (αSMA) and vascular density (CD31) The pancreas contour of the photographed tissue slices was manually outlined. Slices were aligned and stacked to form a 3D volume of the pancreas specimen, which was projected onto the MR images. Stained whole mount sections were aligned with the corresponding tissue photograph and transposed to the MRI accordingly to correlate pathology sections to imaging sections and validate parameters using IHC.

Results: Sixteen patients were included in the study of which four patients have currently been analyzed. Tissue specimens after resection showed good visual agreement with MRI and could be matched using corresponding anatomical landmarks. In addition, Lower D-values, suggesting higher cell density, indeed corresponded with higher stromal content, while higher values on the Ktrans map, suggesting a higher tumor vascularity, corresponded with higher vessel density.

Conclusion: With these preliminary data we demonstrated the feasibility of matching post-operative tissue slices to in vivo MRI of the pancreas. Matching stained whole mount sections to MRI images provides direct information on localization and local tumor heterogeneity for validation of functional MRI parameters. Expanding this work in a larger patient group will provide valuable insights on the underlying biology of functional MRI parameters in pancreatic cancer.

Citation Format: Anne Steins, Remy Klaassen, Oliver Gurney-Champion, Maarten Bijlsma, Jan Paul Medema, Hessel Wijkstra, Geertjan van Tienhoven, Olivier Busch, Cornelis Punt, Marc Besselink, Hanneke Wilmink, Marc van de Vijver, Jaap Stoker, Aart Nederveen, Hanneke van Laarhoven. The role of the tumor microenvironment of pancreatic cancer to predict treatment outcome. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 421. doi:10.1158/1538-7445.AM2015-421

Abstract 5177: Heterogeneity of pancreatic ductal adenocarcinoma visualized

The outcome of pancreatic ductal adenocarcinoma (PDAC) remains dismal. Factors that contribute to the lethality of this disease include its intrinsic resistance to therapeutics, an aggressive growth pattern, and a large degree of both inter- as well as intratumor heterogeneity. All these features have been attributed (at least in part) to the presence and function of a population of pluripotent cells called cancer stem cells. Despite the alleged importance of these cells for clinical outcome, the methods that have been used to study these cells in PDAC are troubled by some serious caveats. Defining important quantitative parameters for these cells in an unbiased, marker-agnostic, way is called for and we aim to achieve this by unbiased tracing methods in patient derived xenografts.

A panel of PDX-derived lines generated in our institute was labeled using the LeGO (Lentiviral Gene Ontology; Weber et al. 2012 Nat. Prot) system to enable tracking of single cell clones by color. The system utilizes three vectors coding for red, green, and blue fluorophores much like a television uses these colors to generate an almost infinite range of colors in the visible range. Nuances in color and intensity are generated by the many possible combinations of fluorophores, the different integration numbers of the genes coding for them, and the variations in expression levels determined by for instance the integration sites. The end result is a population of cells in which each cell is endowed with a unique color. This will allow detection of the offspring of such a cell by identifying clones within a structural unit in for instance a tumor, or in a culture dish, of similar color. The ability to give rise to such a structure is then, depending on the experimental context and outcome, considered a proxy for stem cell function.

Several primary lines have proven amenable to LeGO-marking. These lines showed stable color patterns during culturing in vitro as analyzed by continuous FACS measurements, and tumors derived from marked cells did not show a difference to umarked tumors as assessed by gross histology and growth rate. We are currently testing the ability of these cells to faithfully occupy and mark structural units in PDAC, much like intestinal stem cells would in a lineage tracing experiment in the gut, and derive numbers for stem cell number as well as replacement rate. Experiments are currently being performed to assess the system's potential to measure parameters associated with stemness, and possibly also differentiation status of the original tumor, as the cells grow in vitro. (Radio)chemotherapy regimens are included to formally address the purported resistance of cancer stem cells to these treatments without having to rely on an a priori chosen marker. Furthermore, more detailed comparison should reveal use of LeGO-derived data to measure the intra- and intertumor heterogeneity in PDAC tumor biology in our panel of PDXs.

Citation Format: Veronique Veenstra, Helene Damhofer, Tom van Leusden, Jan Kessler, Jan Paul Medema, Hanneke van Laarhoven, Louis Vermeulen, Maarten Bijlsma. Heterogeneity of pancreatic ductal adenocarcinoma visualized. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5177. doi:10.1158/1538-7445.AM2015-5177

Pyuria is absent during urinary tract infections in neutropenic patients

To investigate the diagnostic significance of a normal urine sediment in the work-up for fever of unknown origin in neutropenia. Urinary tract infection was defined as ≥10(5) urinary pathogens in the absence of another focus. Pyuria was found in only 1/23 neutropenic episodes compared to 21/31 in controls (P < 0.0001).

Assessment of a take home child supplementary feeding programme in a high density suburb of Mutare City, Zimbabwe

OBJECTIVE

Assessment of a child supplementary feeding programme.

SETTING

Mutare City Health Department has a long existing, ongoing supplementary feeding programme for undernourished children. We assessed the programme in Sakubva, Mutare's oldest, largest, poorest and most densely populated high density suburb. During the time of assessment, after the 1994/95 poor rainy season, levels of undernutrition were more that double the normal levels.

DESIGN

Analysis of clinic records. Results are illustrated with findings from students on attachment who studied underlying causes of undernutrition.

SUBJECTS

The supplementary feeding programme is a health service to underweight children who attend our clinics. Assessment of the programme was done on all children that regularly made use of this service between July 1995 and May 1996 in Sakubva (n = 190).

RESULTS

The child supplementary feeding programme does make an impact as 83% of the children attending regularly, improve. The impact of a child supplementary feeding programme in terms of growth development in undernourished children depends on the underlying chronic diseases that the children are presenting.

CONCLUSIONS

Referral of children that do not improve for check up and treatment is urgent and should be a routine procedure in Well Baby Clinics. In an environment of poverty and poor weaning practices, often aggravated by underlying illnesses, a child supplementary feeding programme can improve growth in undernourished children, within the limitations of its coverage.

Theory of Interacting Quantum Gases

We present a unified picture of the interaction effects in dilute atomic quantum gases. We consider fermionic as well as bosonic gases and, in particular, discuss for both forms of statistics the fundamental differences between a gas with effectively repulsive and a gas with effectively attractive inter atomic interactions, i.e., between a gas with either a positive or a negative scattering length.