Publications

Rebecca Halbach et al.

RIMLS awards annualy a prize for the best peer-reviewed publication. The publication should relate to a major scientific "breakthrough" that advances scientific understanding.

The winner of the RIMLS Breakthrough Publication: Rebecca Halbach et al. (link)  A satellite repeat-derived piRNA controls embryonic development of Aedes

Covid-19 related publications can be found here.

Infectious diseases and global health

Priem B, van Leent MMT, Teunissen AJP , Sofias AM, Mourits VP, Willemsen L, Klein ED, Oosterwijk RS, Meerwaldt AE, Munitz J, Prévot G, Verschuur AV, Nauta SA, van Leeuwen EM, Fisher EL, de Jong KAM, Zhao Y, Toner YC,  Soultanidis G, Calcagno C, Bomans PHH, Friedrich H, Sommerdijk N, Reiner T, Duivenvoorden R, Zupančič E, Di Martino JS, Kluza E, Rashidian M, Ploegh HL, Dijkhuizen RM, Hak S, Pérez-Medina C, Bravo-Cordero JJ, de Winther MPJ, Joosten LAB, van Elsas A, Fayad ZA, Rialdi A, Torre D, Guccione E, Ochando J, Netea MG, Griffioen AW, Mulder WJM. Trained immunity-promoting nanobiologic therapy suppresses tumor growth and potentiates checkpoint inhibition. Cell 183:786-801, 2020. PMID 33125893.

Trained immunity, a functional state of myeloid cells, has been proposed as a compelling immune-oncological target. Its efficient induction requires direct engagement of myeloid progenitors in the bone marrow. For this purpose, we developed a bone marrow-avid nanobiologic platform designed specifically to induce trained immunity. We established the potent anti-tumor capabilities of our lead candidate MTP10-HDL in a B16F10 mouse melanoma model. These anti-tumor effects result from trained immunity-induced myelopoiesis caused by epigenetic rewiring of multipotent progenitors in the bone marrow, which overcomes the immunosuppressive tumor microenvironment. Furthermore, MTP10-HDL nanotherapy potentiates checkpoint inhibition in this melanoma model refractory to anti-PD-1 and anti-CTLA-4 therapy. Finally, we determined MTP10-HDL's favorable biodistribution and safety profile in non-human primates. In conclusion, we show that rationally designed nanobiologics can promote trained immunity and elicit a durable anti-tumor response either as a monotherapy or in combination with checkpoint inhibitor drugs.

Walk J, Keramati F, de Bree LCJ, Arts RJW, Blok B, Netea MG, Stunnenberg HG and Sauerwein RW. Controlled Human Malaria Infection Induces Long-Term Functional Changes in Monocytes. Front Mol Biosci 7:604553, 2020. PMID 33324683.

Innate immune memory responses (also termed "trained immunity") have been described in monocytes after BCG vaccination and after stimulation in vitro with microbial and endogenous ligands such as LPS, β-glucan, oxidized LDL, and monosodium urate crystals. However, whether clinical infections are also capable of inducing a trained immunity phenotype remained uncertain. We evaluated whether Plasmodium falciparum infection can induce innate immune memory by measuring monocyte-derived cytokine production from five volunteers undergoing Controlled Human Malaria Infection. Monocyte responses followed a biphasic pattern: during acute infection, monocytes produced lower amounts of inflammatory cytokines upon secondary stimulation, but 36 days after malaria infection they produced significantly more IL-6 and TNF-α in response to various stimuli. Furthermore, transcriptomic and epigenomic data analysis revealed a clear reprogramming of monocytes at both timepoints, with long-term changes of H3K4me3 at the promoter regions of inflammatory genes that remain present for several weeks after parasite clearance. These findings demonstrate an epigenetic basis of trained immunity induced by human malaria in vivo.

Halbach R, Miesen P, Joosten J, Taşköprü E, Rondeel I, Pennings B, Vogels CBF, Merkling SH, Koenraadt CJ, Lambrechts L, van Rij RP. A satellite repeat-derived piRNA controls embryonic development of Aedes. Nature 580, 274–277, 2020. PMID 32269344.

Tandem repeat elements such as the diverse class of satellite repeats occupy large parts of eukaryotic chromosomes, mostly at centromeric, pericentromeric, telomeric and subtelomeric regions1. However, some elements are located in euchromatic regions throughout the genome and have been hypothesized to regulate gene expression in cis by modulating local chromatin structure, or in trans via transcripts derived from the repeats2-4. Here we show that a satellite repeat in the mosquito Aedes aegypti promotes sequence-specific gene silencing via the expression of two PIWI-interacting RNAs (piRNAs). Whereas satellite repeats and piRNA sequences generally evolve extremely quickly5-7, this locus was conserved for approximately 200 million years, suggesting that it has a central function in mosquito biology. piRNA production commenced shortly after egg laying, and inactivation of the more abundant piRNA resulted in failure to degrade maternally deposited transcripts in the zygote and developmental arrest. Our results reveal a mechanism by which satellite repeats regulate global gene expression in trans via piRNA-mediated gene silencing that is essential for embryonic development.

Covid-19 related publications can be found here.

Reconstructive and regenerative medicine

Xu Y, Nudelman F, Eren ED, Wirix MJM, Cantaert B, Nijhuis WH, Hermida-Merino D, Portale G, Bomans PHH, Ottmann C, Friedrich H, Bras W, Akiva A, Orgel JPRO, Meldrum FC, Sommerdijk NAJM. Intermolecular channels direct crystal orientation in mineralized collagen. Nat Commun 11:5068, 2020. PMID 33033251.

The mineralized collagen fibril is the basic building block of bone, and is commonly pictured as a parallel array of ultrathin carbonated hydroxyapatite (HAp) platelets distributed throughout the collagen. This orientation is often attributed to an epitaxial relationship between the HAp and collagen molecules inside 2D voids within the fibril. Although recent studies have questioned this model, the structural relationship between the collagen matrix and HAp, and the mechanisms by which collagen directs mineralization remain unclear. Here, we use XRD to reveal that the voids in the collagen are in fact cylindrical pores with diameters of ~2 nm, while electron microscopy shows that the HAp crystals in bone are only uniaxially oriented with respect to the collagen. From in vitro mineralization studies with HAp, CaCO₃ and γ-FeOOH we conclude that confinement within these pores, together with the anisotropic growth of HAp, dictates the orientation of HAp crystals within the collagen fibril.

Nadar RA, Farbod K, Codee-van der Schilden K, Schlatt L, Crone B, Asokan N, Curci A, Brand M, Bornhaeuser M, Iafisco M, Margiotta N, Karst U, Heskamp S, Boerman OC, van den Beucken JJJP, Leeuwenburgh SCG. Targeting of radioactive platinum-bisphosphonate anticancer drugs to bone of high metabolic activity. Sci Rep 10:5889, 2020. PMID 32246003.

Platinum-based chemotherapeutics exhibit excellent antitumor properties. However, these drugs cause severe side effects including toxicity, drug resistance, and lack of tumor selectivity. Tumor-targeted drug delivery has demonstrated great potential to overcome these drawbacks. Herein, we aimed to design radioactive bisphosphonate-functionalized platinum (^195mPt-BP) complexes to confirm preferential accumulation of these Pt-based drugs in metabolically active bone. In vitro NMR studies revealed that release of Pt from Pt BP complexes increased with decreasing pH. Upon systemic administration to mice, Pt-BP exhibited a 4.5-fold higher affinity to bone compared to platinum complexes lacking the bone-seeking bisphosphonate moiety. These Pt-BP complexes formed less Pt-DNA adducts compared to bisphosphonate-free platinum complexes, indicating that in vivo release of Pt from Pt-BP complexes proceeded relatively slow. Subsequently, radioactive ^195mPt-BP complexes were synthesized using ^195mPt(NO₃)₂(en) as precursor and injected intravenously into mice. Specific accumulation of ^195mPt-BP was observed at skeletal sites with high metabolic activity using micro-SPECT/CT imaging. Furthermore, laser ablation-ICP-MS imaging of proximal tibia sections confirmed that ^195mPt BP co-localized with calcium in the trabeculae of mice tibia.

 Krielen P, Stommel MWJ, Pargmae P, Bouvy ND, Bakkum EA, Ellis H, Parker MC, Griffiths EA, van Goor H, Ten Broek RPG. Adhesion-related readmissions after open and laparoscopic surgery: a retrospective cohort study (SCAR update). Lancet 395:33-41. 2020. PMID 31908284.

Background: Adhesions are the most common driver of long-term morbidity after abdominal surgery. Although laparoscopy can reduce adhesion formation, the effect of minimally invasive surgery on long-term adhesion-related morbidity remains unknown. We aimed to assess the impact of laparoscopy on adhesion-related readmissions in a population-based cohort.

Methods: We did a retrospective cohort study of patients of any age who had abdominal or pelvic surgery done using laparoscopic or open approaches between June 1, 2009, and June 30, 2011, using validated population data from the Scottish National Health Service. All patients who had surgery were followed up until Dec 31, 2017. The primary outcome measure was the incidence of hospital readmissions directly related to adhesions in the laparoscopic and open surgery cohorts at 5 years. Readmissions were categorised as directly related to adhesions, possibly related to adhesions, and readmissions for an operation that was potentially complicated by adhesions. We did subgroup analyses of readmissions by anatomical site of surgery and used Kaplan-Meier analyses to assess differences in survival across subgroups. We used multivariable Cox-regression analysis to determine whether surgical approach was an independent and significant risk factor for adhesion-related readmissions.

Findings: Between June 1, 2009, and June 30, 2011, 72 270 patients had an index abdominal or pelvic surgery, of whom 21 519 (29·8%) had laparoscopic index surgery and 50 751 (70·2%) had open surgery. Of the 72 270 patients who had surgery, 2527 patients (3·5%) were readmitted within 5 years of surgery for disorders directly related to adhesions, 12 687 (17·6%) for disorders possibly related to adhesions, and 9436 (13·1%) for operations potentially complicated by adhesions. Of the 21 519 patients who had laparoscopic surgery, 359 (1·7% [95% CI 1·5-1·9]) were readmitted for disorders directly related to adhesions compared with 2168 (4·3% [4·1-4·5]) of 50 751 patients in the open surgery cohort (p<0·0001). 3443 (16·0% [15·6-16·4]) of 21 519 patients in the laparoscopic surgery cohort were readmitted for disorders possibly related to adhesions compared with 9244 (18·2% [17·8-18·6]) of 50 751 patients in the open surgery cohort (p<0·005). In multivariate analyses, laparoscopy reduced the risk of directly related readmissions by 32% (hazard ratio [HR] 0·68, 95% CI 0·60-0·77), and of possibly related readmissions by 11% (HR 0·89, 0·85-0·94) compared with open surgery. Procedure type, malignancy, sex, and age were also independently associated with risk of adhesion-related readmissions.

Interpretation: Laparoscopic surgery reduces the incidence of adhesion-related readmissions. However, the overall burden of readmissions associated with adhesions remains high. With further increases in the use of laparoscopic surgery expected in the future, the effect at the population level might become larger. Further steps remain necessary to reduce the incidence of adhesion-related postsurgical complications.

Covid-19 related publications can be found here.

Cancer development and immune defense

Perino, M, van Mierlo, G, Loh, C, Wardle, SMT, Zijlmans, DW, Marks, H et al.. Two functional axes of feedback-enforced PRC2 recruitment in mouse embryonic stem cells. Stem Cell Reports 15:1287-1300, 2020. PMID: 32763159.

Polycomb Repressive Complex 2 (PRC2) plays an essential role in gene repression during development, catalyzing H3 lysine 27 trimethylation (H3K27me3). MTF2 in the PRC2.1 sub-complex, and JARID2 in PRC2.2, are central in core PRC2 recruitment to target genes in mouse embryonic stem cells (mESCs). To investigate how PRC2.1 and PRC2.2 cooperate, we combined Polycomb mutant mESCs with chemical inhibition of binding to H3K27me3. We find that PRC2.1 and PRC2.2 mediate two distinct paths for recruitment, which are mutually reinforced. Whereas PRC2.1 recruitment is mediated by MTF2 binding to DNA, JARID2-containing PRC2.2 recruitment is more dependent on PRC1. Both recruitment axes are supported by core subunit EED binding to H3K27me3, but EED inhibition exhibits a more pronounced effect in Jarid2 null cells. Finally, we show that PRC1 and PRC2 enhance reciprocal binding. Together, these data disentangle the interdependent interactions that are important for PRC2 recruitment.

Gritsenko PG, Atlasy N, Dieteren CEJ, Navis AC, Venhuizen JH, Veelken C, Schubert D, Acker-Palmer A, Westerman BA, Wurdinger T, Leenders W, Wesseling P, Stunnenberg HG, Friedl P. p120-catenin-dependent collective brain infiltration by glioma cell networks. Nat Cell Biol 22:97-107, 2020. PMID 31907411.

Diffuse brain infiltration by glioma cells causes detrimental disease progression, but its multicellular coordination is poorly understood. We show here that glioma cells infiltrate the brain collectively as multicellular networks. Contacts between moving glioma cells are adaptive epithelial-like or filamentous junctions stabilized by N-cadherin, β-catenin and p120-catenin, which undergo kinetic turnover, transmit intercellular calcium transients and mediate directional persistence. Downregulation of p120-catenin compromises cell-cell interaction and communication, disrupts collective networks, and both the cadherin and RhoA binding domains of p120-catenin are required for network formation and migration. Deregulating p120-catenin further prevents diffuse glioma cell infiltration of the mouse brain with marginalized microlesions as the outcome. Transcriptomics analysis has identified p120-catenin as an upstream regulator of neurogenesis and cell cycle pathways and a predictor of poor clinical outcome in glioma patients. Collective glioma networks infiltrating the brain thus depend on adherens junctions dynamics, the targeting of which may offer an unanticipated strategy to halt glioma progression.

Di Blasio S, van Wigcheren GF, Becker A, van Duffelen A, Gorris M, Verrijp K, Stefanini I,  Bakker GJ, Bloemendal M, Halilovic A, Vasaturo A, Bakdash G, Hato SV, de Wilt JHW, Schalkwijk  J, de Vries IJM, Textor JC, van den Bogaard EH, Tazzari M, Figdor CG. The tumour microenvironment shapes dendritic cell plasticity in a human organotypic melanoma culture. Nat Commun 11:2749, 2020. PMID 32488012.

The tumour microenvironment (TME) forms a major obstacle in effective cancer treatment and for clinical success of immunotherapy. Conventional co-cultures have shed light onto multiple aspects of cancer immunobiology, but they are limited by the lack of physiological complexity. We develop a human organotypic skin melanoma culture (OMC) that allows real-time study of host-malignant cell interactions within a multicellular tissue architecture. By co-culturing decellularized dermis with keratinocytes, fibroblasts and immune cells in the presence of melanoma cells, we generate a reconstructed TME that closely resembles tumour growth as observed in human lesions and supports cell survival and function. We demonstrate that the OMC is suitable and outperforms conventional 2D co-cultures for the study of TME-imprinting mechanisms. Within the OMC, we observe the tumour-driven conversion of cDC2s into CD14+ DCs, characterized by an immunosuppressive phenotype. The OMC provides a valuable approach to study how a TME affects the immune system.

Covid-19 related publications can be found here.

Urological cancers

Benoist GE, van Oort IM, Boerrigter E, Verhaegh GW, van Hooij O, Groen L, Smit F, de Mol P, Hamberg P, Dezentjé VO, Mehra N, Gerritsen W, Somford DM, van Erp NPH, Schalken JA. Prognostic Value of Novel liquid biomarkers in patients with metastatic castration-resistant prostate cancer treated with enzalutamide: a prospective observational study. Clin Chem 66:842-851, 2020. PMID 32408351.

Background: Several treatment options were recently added for metastatic castration-resistant prostate cancer (mCRPC). However, response to therapy is variable, and biomarkers that can guide treatment selection and response evaluation are lacking. Circulating RNAs are a promising source of biomarkers. We explored messenger RNAs (mRNAs), microRNAs (miRNAs), and long noncoding RNAs (lncRNAs) as potential biomarkers in liquid biopsies of patients with mCRPC treated with enzalutamide.

Methods: Forty patients were included in this prospective multicenter observational study. Whole blood was drawn at baseline and 1, 3, and 6 months after start of therapy. Four mRNAs, 6 miRNAs, and 5 lncRNAs were analyzed by quantitative PCR. RNA levels in 30 healthy individuals were used as controls. RNA expression data were analyzed by Kaplan-Meier and Cox regression analyses, and the primary end point was progression-free survival. Clinical factors were included in the multivariable Cox regression analysis.

Results: Levels of 2 miRNAs, miR-375 and miR-3687, and 1 lncRNA, N-acetylated alpha-linked acidic dipeptidase like 2 antisense RNA 2 (NAALADL2-AS2), were more than 2-fold higher in patients with mCRPC compared with healthy volunteers. Patients with higher levels of miR-375 or miR-3687 showed a shorter time to progression. Patients with higher levels of NAALADL2-AS2 showed a longer time to progression. In the multivariable Cox regression analysis, higher miR-375, miR-3687 and serum prostate-specific antigen concentrations were shown to be independent predictors for shorter time to progression.

Conclusions: We identified miR-3687 as a novel prognostic marker for response in patients with CRPC treated with enzalutamide, and we confirmed the prognostic value of miR-375.

van Heijster FHA, Heskamp S, Breukels V, Veltien A, Franssen GM, Jansen KCFJ, Boerman OC, Schalken JA, Scheenen TWJ, Heerschap A. Pyruvate-lactate exchange and glucose uptake in human prostate cancer cell models. A study in xenografts and suspensions by hyperpolarized [1-13 C]pyruvate MRS and [18 F]FDG-PET. NMR Biomed 33:e4362, 2020. PMID 32662543.

Reprogramming of energy metabolism in the development of prostate cancer can be exploited for a better diagnosis and treatment of the disease. The goal of this study was to determine whether differences in glucose and pyruvate metabolism of human prostate cancer cells with dissimilar aggressivenesses can be detected using hyperpolarized [1-¹³ C]pyruvate MRS and [¹⁸ F]FDG-PET imaging, and to evaluate whether these measures correlate. For this purpose, we compared murine xenografts of human prostate cancer LNCaP cells with those of more aggressive PC3 cells. [1-¹³ C]pyruvate was hyperpolarized by dissolution dynamic nuclear polarization (dDNP) and [1-¹³ C]pyruvate to lactate conversion was followed by ¹³ C MRS. Subsequently [¹⁸ F]FDG uptake was investigated by static and dynamic PET measurements. Standard uptake values (SUVs) for [¹⁸ F]FDG were significantly higher for xenografts of PC3 compared with those of LNCaP. However, we did not observe a difference in the average apparent rate constant k_pl of ¹³ C label exchange from pyruvate to lactate between the tumor variants. A significant negative correlation was found between SUVs from [¹⁸ F]FDG PET measurements and k_pl values for the xenografts of both tumor types. The k_pl rate constant may be influenced by various factors, and studies with a range of prostate cancer cells in suspension suggest that LDH inhibition by pyruvate may be one of these. Our results indicate that glucose and pyruvate metabolism in the prostate cancer cell models differs from that in other tumor models and that [¹⁸ F]FDG-PET can serve as a valuable complementary tool in dDNP studies of aggressive prostate cancer with [1-¹³ C]pyruvate.

Witjes JA, Babjuk M, Bellmunt J, Bruins HM, De Reijke TM, De Santis M, Gillessen S, James N, Maclennan S, Palou J, Powles T, Ribal MJ, Shariat SF, Der Kwast TV, Xylinas E, Agarwal N, Arends T, Bamias A, Birtle A, Black PC, Bochner BH, Bolla M, Boormans JL, Bossi A, Briganti A, Brummelhuis I, Burger M, Castellano D, Cathomas R, Chiti A, Choudhury A, Compérat E, Crabb S, Culine S, De Bari B, De Blok W, J L De Visschere P, Decaestecker K, Dimitropoulos K, Dominguez-Escrig JL, Fanti S, Fonteyne V, Frydenberg M, Futterer JJ, Gakis G, Geavlete B, Gontero P, Grubmüller B, Hafeez S, Hansel DE, Hartmann A, Hayne D, Henry AM, Hernandez V, Herr H, Herrmann K, Hoskin P, Huguet J, Jereczek-Fossa BA, Jones R, Kamat AM, Khoo V, Kiltie AE, Krege S, Ladoire S, Lara PC, Leliveld A, Linares-Espinós E, Løgager V, Lorch A, Loriot Y, Meijer R, Mir MC, Moschini M, Mostafid H, Müller AC, Müller CR, N'Dow J, Necchi A, Neuzillet Y, Oddens JR, Oldenburg J, Osanto S, J G Oyen W, Pacheco-Figueiredo L, Pappot H, Patel MI, Pieters BR, Plass K, Remzi M, Retz M, Richenberg J, Rink M, Roghmann F, Rosenberg JE, Rouprêt M, Rouvière O, Salembier C, Salminen A, Sargos P, Sengupta S, Sherif A, Smeenk RJ, Smits A, Stenzl A, Thalmann GN, Tombal B, Turkbey B, Lauridsen SV, Valdagni R, Van Der Heijden AG, Van Poppel H, Vartolomei MD, Veskimäe E, Vilaseca A, Rivera FAV, Wiegel T, Wiklund P, Williams A, Zigeuner R, Horwich A. EAU-ESMO Consensus statements on the management of advanced and variant bladder cancer-an international collaborative multistakeholder effort†: under the auspices of the EAU-ESMO guidelines committees. Eur Urol 77:223-250, 2020. PMID 31753752.

Background: Although guidelines exist for advanced and variant bladder cancer management, evidence is limited/conflicting in some areas and the optimal approach remains controversial.

Objective: To bring together a large multidisciplinary group of experts to develop consensus statements on controversial topics in bladder cancer management.

Design: A steering committee compiled proposed statements regarding advanced and variant bladder cancer management which were assessed by 113 experts in a Delphi survey. Statements not reaching consensus were reviewed; those prioritised were revised by a panel of 45 experts prior to voting during a consensus conference.

Setting: Online Delphi survey and consensus conference.

Participants: The European Association of Urology (EAU), the European Society for Medical Oncology (ESMO), experts in bladder cancer management.

Outcome measurements and statistical analysis: Statements were ranked by experts according to their level of agreement: 1-3 (disagree), 4-6 (equivocal), and 7-9 (agree). A priori (level 1) consensus was defined as ≥70% agreement and ≤15% disagreement, or vice versa. In the Delphi survey, a second analysis was restricted to stakeholder group(s) considered to have adequate expertise relating to each statement (to achieve level 2 consensus).

Results and limitations: Overall, 116 statements were included in the Delphi survey. Of these statements, 33 (28%) achieved level 1 consensus and 49 (42%) achieved level 1 or 2 consensus. At the consensus conference, 22 of 27 (81%) statements achieved consensus. These consensus statements provide further guidance across a broad range of topics, including the management of variant histologies, the role/limitations of prognostic biomarkers in clinical decision making, bladder preservation strategies, modern radiotherapy techniques, the management of oligometastatic disease, and the evolving role of checkpoint inhibitor therapy in metastatic disease.

Conclusions: These consensus statements provide further guidance on controversial topics in advanced and variant bladder cancer management until a time when further evidence is available to guide our approach.

Patient summary: This report summarises findings from an international, multistakeholder project organised by the EAU and ESMO. In this project, a steering committee identified areas of bladder cancer management where there is currently no good-quality evidence to guide treatment decisions. From this, they developed a series of proposed statements, 71 of which achieved consensus by a large group of experts in the field of bladder cancer. It is anticipated that these statements will provide further guidance to health care professionals and could help improve patient outcomes until a time when good-quality evidence is available.

Covid-19 related publications can be found here.

Tumors of the digestive tract

Boss M, Bos D, Frielink C, Sandker G, Ekim S, Marciniak C, Pattou F, van Dam G, van Lith S, Brom M, Gotthardt M, Buitinga M. Targeted Optical Imaging of the Glucagonlike Peptide 1 Receptor Using Exendin-4-IRDye 800CW. J Nucl Med 61:1066-1071, 2020. PMID: 31924726.

The treatment of choice for insulinomas and focal lesions in congenital hyperinsulinism (CHI) is surgery. However, intraoperative detection can be challenging. This challenge could be overcome with intraoperative fluorescence imaging, which provides real-time lesion detection with a high spatial resolution. Here, a novel method for targeted near-infrared (NIR) fluorescence imaging of glucagonlike peptide 1 receptor (GLP-1R)-positive lesions, using the GLP-1 agonist exendin-4 labeled with IRDye 800CW, was examined in vitro and in vivo.

Methods: A competitive binding assay was performed using Chinese hamster lung (CHL) cells transfected with GLP-1R. Tracer biodistribution was determined in BALB/c nude mice bearing subcutaneous CHL-GLP-1R xenografts. In vivo NIR fluorescence imaging of CHL-GLP-1R xenografts was performed. Localization of the tracer in the pancreatic islets of BALB/c nude mice was examined using fluorescence microscopy. Laparoscopic imaging was performed to detect the fluorescent signal of the tracer in the pancreas of mini pigs.

Results: Exendin-4-IRDye 800CW binds GLP-1R with a half-maximal inhibitory concentration of 3.96 nM. The tracer accumulates in CHL-GLP-1R xenografts. Subcutaneous CHL-GLP-1R xenografts were visualized using in vivo NIR fluorescence imaging. The tracer accumulates specifically in the pancreatic islets of mice, and a clear fluorescent signal was detected in the pancreas of mini pigs.

Conclusion: These data provide the first in vivo evidence of the feasibility of targeted fluorescence imaging of GLP-1R-positive lesions. Intraoperative lesion delineation using exendin-4-IRDye 800CW could benefit open as well as laparoscopic surgical procedures for removal of insulinomas and focal lesions in CHI.

Dinmohamed AG, Visser O, Verhoeven RHA, Louwman MWJ, van Nederveen FH, Willems SM, Merkx MAW, Lemmens VEPP, Nagtegaal ID, Siesling S. Fewer cancer diagnoses during the COVID-19 epidemic in the Netherlands. Lancet Oncol 21:750-751, 2020. PMID 32359403.

The dreadful consequences of coronavirus disease 2019 (COVID-19) put an unprecedented pressure on health-care services across the globe. The Netherlands, a country with 17·4 million inhabitants that provides its citizens with universal access to essential health-care services—with the general practitioner as the gatekeeper to secondary care—is no exception in this regard.

The first patient with COVID-19 in the Netherlands was confirmed on Feb 27, 2020, in the southern part of the country. Thereafter, the disease spread rapidly throughout the country. Subsequently, strict social distancing policies were implemented by the Dutch government as of March 15, 2020, to mitigate the spread of COVID-19.

Elsayed FA, Grolleman JE, Ragunatha A, NTHL1 study group, Buchanan DD, van Wezel T, de Voer RM. Monoallelic NTHL1 loss-of-function variants and risk of polyposis and colorectal cCancer. Gastroenterology 159:2241-2243.e6, 2020. PMID 32860789.

The endonuclease III-like protein 1, encoded by NTHL1, is a bifunctional glycosylase involved in base-excision repair (BER) that recognizes and removes oxidized pyrimidines. Similar to biallelic loss-of-function (LoF) variants in MUTYH, biallelic LoF variants in NTHL1 predispose to colorectal polyps and colorectal cancer (CRC). Recently, a multitumor phenotype was observed in individuals diagnosed with NTHL1 deficiency. Carriers of monoallelic pathogenic variants in MUTYH have an increased, albeit small, risk of CRC. Thus far, it is unknown if monoallelic NTHL1 LoF variants also increase the risk of polyposis and/or CRC. This information is especially important for carriers of the most common LoF variant in NTHL1 (p.(Gln90∗); NM_002528.5), which is heterozygous in approximately 0.28% of the general population. Identification of monoallelic NTHL1 LoF variants currently presents a clinical conundrum regarding how best to counsel carriers with respect to their cancer risk because of the lack of published evidence. Here, we show that monoallelic LoF variants in NTHL1 are not enriched in individuals with polyposis and/or CRC compared to the general population. Furthermore, 13 colorectal tumors from NTHL1 LoF carriers did not show a somatic second hit, and we did not find evidence of a main contribution of mutational signature SBS30, the signature associated with NTHL1 deficiency, suggesting that monoallelic loss of NTHL1 does not substantially contribute to colorectal tumor development.

Covid-19 related publications can be found here.

Inflammatory diseases

Smits JPH, Ederveen THA, Rikken G, van den Brink NJM, van Vlijmen-Willems IMJJ, Boekhorst J, Kamsteeg M, Schalkwijk J, van Hijum SAFT, Zeeuwen PLJM, van den Bogaard EH. Targeting the cutaneous microbiota in atopic dermatitis by coal tar via AHR-dependent induction of antimicrobial peptides. J Invest Dermatol 140:415-424.e10, 2020. PMID 31344386.

Skin colonization by Staphylococcus aureus and its relative abundance is associated with atopic dermatitis (AD) disease severity and treatment response. Low levels of antimicrobial peptides in AD skin may be related to the microbial dysbiosis. Therapeutic targeting of the skin microbiome and antimicrobial peptide expression can, therefore, restore skin homeostasis and combat AD. In this study, we analyzed the cutaneous microbiome composition in 7 patients with AD and 10 healthy volunteers upon topical coal tar or vehicle treatment. We implemented and validated a Staphylococcus-specific single-locus sequence typing approach combined with classic 16S ribosomal RNA marker gene sequencing to study the bacterial composition. During coal tar treatment, Staphylococcus abundance decreased, and Propionibacterium abundance increased, suggesting a shift of the microbiota composition toward that of healthy controls. We, furthermore, identified a hitherto unknown therapeutic mode of action of coal tar, namely the induction of keratinocyte-derived antimicrobial peptides via activation of the aryl hydrocarbon receptor. Restoring antimicrobial peptide levels in AD skin via aryl hydrocarbon receptor-dependent transcription regulation can be beneficial by creating a (anti)microbial milieu that is less prone to infection and inflammation. This underscores the importance of coal tar in the therapeutic aryl hydrocarbon receptor armamentarium and highlights the aryl hydrocarbon receptor as a target for drug development.

Benner M, Feyaerts D, García CC, Inci N, López SC, Fasse E, Shadmanfar W, van der Heijden OWH, Gorris MAJ, Joosten I, Ferwerda G, van der Molen RG. Clusters of tolerogenic B cells feature in the dynamic immunological landscape of the pregnant uterus. Cell Rep 32:108204, 2020. PMID 32997982.

Well-timed interaction of correctly functioning maternal immune cells is essential to facilitate healthy placenta formation, because the uterine immune environment has to tolerate the semi-allogeneic fetus and allow adequate trophoblast invasion. Here, we assess the uterine immune signature before and during pregnancy. Extensive supervised and unsupervised flow cytometry clustering strategies not only show a general increase in immune memory throughout pregnancy but also reveal the continuous presence of B cells. Contrary to the belief that B cells are merely a consequence of uterine pathology, decidual B cells produce IL-10 and are found to be localized in clusters, together with Foxp3^pos T cells. Our findings therefore suggest a role for B cells in healthy pregnancy.

Ulijn E, den Broeder N, Wientjes M, van Herwaarden N, Meek I, Tweehuysen L, van der Maas A, van den Bemt BJ, den Broeder AA. Therapeutic drug monitoring of adalimumab in RA: no predictive value of adalimumab serum levels and anti-adalimumab antibodies for prediction of response to the next bDMARD. Ann Rheum Dis 79:867-873, 2020. PMID 32317314.

Background: After adalimumab treatment failure, tumour necrosis factor inhibition (TNFi) and non-TNFi biological disease-modifying anti-rheumatic drugs (bDMARDs) are equally viable options on a group level as subsequent treatment in rheumatoid arthritis (RA) based on the current best evidence synthesis. However, preliminary data suggest that anti-adalimumab antibodies (anti-drug antibodies, ADA) and adalimumab serum levels (ADL) during treatment predict response to a TNFi as subsequent treatment.

Objective: To validate the association of presence of ADA and/or low ADL with response to a subsequent TNFi bDMARD or non-TNFi bDMARD. Sub-analyses were performed for primary and secondary non-responders.

Methods: A diagnostic test accuracy retrospective cohort study was done in consenting RA patients who discontinued adalimumab after >3 months of treatment due to inefficacy and started another bDMARD. Inclusion criteria included the availability of (random timed) serum samples between ≥8 weeks after start and ≤2 weeks after discontinuation of adalimumab, and clinical outcome measurements Disease Activity Score in 28 joints - C-reactive protein (DAS28-CRP) between 3 to 6 months after treatment switch. Test characteristics for EULAR (European League Against Rheumatism) good response (DAS28-CRP based) after treatment with the next (non-)TNFi bDMARD were assessed using area under the receiver operating characteristic and sensitivity/specificity.

Results: 137 patients were included. ADA presence was not predictive for response in switchers to a TNFi (sensitivity/specificity 18%/75%) or a non-TNFi (sensitivity/specificity 33%/70%). The same was true for ADL levels in patients that switched to a TNFi (sensitivity/specificity 50%/52%) and patients that switched to a non-TNFi (sensitivity/specificity 32%/69%). Predictive value of ADA and ADL were similar for both primary and secondary non-responders to adalimumab.

Conclusions: In contrast to earlier research, we could not find predictive value for response to a second TNFi or non-TNFi for either ADA or random timed ADL.

Covid-19 related publications can be found here.

Metabolic disorders

Kaplanis J, Samocha KE, Wiel L, Zhang Z, Arvai KJ, Eberhardt RY, Gallone G, Lelieveld SH, Martin HC, McRae JF, Short PJ, Torene RI, de Boer E, Danecek P, Gardner EJ, Huang N, Lord J, Martincorena I, Pfundt R, Reijnders MRF, Yeung A, Yntema HG, Deciphering Developmental Disorders Study*, Vissers LELM, Juusola J, Wright CF, Brunner HG, Firth HV, FitzPatrick DR, Barrett JC, Hurles ME, Gilissen C & Retterer K. Evidence for 28 genetic disorders discovered by combining healthcare and research data. Nature 586:757-762, 2020. PMID 33057194.

De novo mutations in protein-coding genes are a well-established cause of developmental disorders1. However, genes known to be associated with developmental disorders account for only a minority of the observed excess of such de novo mutations1,2. Here, to identify previously undescribed genes associated with developmental disorders, we integrate healthcare and research exome-sequence data from 31,058 parent-offspring trios of individuals with developmental disorders, and develop a simulation-based statistical test to identify gene-specific enrichment of de novo mutations. We identified 285 genes that were significantly associated with developmental disorders, including 28 that had not previously been robustly associated with developmental disorders. Although we detected more genes associated with developmental disorders, much of the excess of de novo mutations in protein-coding genes remains unaccounted for. Modelling suggests that more than 1,000 genes associated with developmental disorders have not yet been described, many of which are likely to be less penetrant than the currently known genes. Research access to clinical diagnostic datasets will be critical for completing the map of genes associated with developmental disorders.

Xie J, Bao M, Hu X, Koopman WJH, Huck WTS. Energy expenditure during cell spreading influences the cellular response to matrix stiffness. Biomaterials 267:120494, 2020. PMID 33130323.

Cells respond to the mechanical properties of the extracellular matrix (ECM) through formation of focal adhesions (FAs), re-organization of the actin cytoskeleton and adjustment of cell contractility. These are energy-demanding processes, but a potential causality between mechanical cues (matrix stiffness) and cellular (energy) metabolism remains largely unexplored. Here, we cultured human mesenchymal stem cells (hMSCs) on stiff (20 kPa) or soft (1 kPa) substrate and demonstrate that cytoskeletal reorganization and FA formation spreading on stiff substrates lead to a drop in intracellular ATP levels, correlating with activation of AMP-activated protein kinase (AMPK). The resulting increase in ATP levels further facilitates cell spreading and reinforces cell tension of the steady state, and coincides with nuclear localization of YAP/TAZ and Runx2. While on soft substrates (1 kPa), lowered ATP levels limit these cellular mechanoresponses. Furthermore, genetic ablation of AMPK lowered cellular ATP levels on stiff substrate and strongly reduced responses to substrate stiffness. Together, these findings reveal a hitherto unidentified relationship between energy expenditure and the cellular mechanoresponse, and point to AMPK as a key mediator of stem cell fate in response to ECM mechanics.

Shen JJ, Wortmann SB, de Boer L, Kluijtmans LAJ, Huigen MCDG, Koch J, Ross S, Collins CD, van der Lee R, van Karnebeek CDM, Hegde MR The role of clinical response to treatment in determining pathogenicity of genomic variants. Genet Med doi: 10.1038/s41436-020-00996-9, 2020. PMID: 33087887.

Purpose: The 2015 American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines for the interpretation of sequence variants provide a framework to standardize terminology in the classification of variants uncovered through genetic testing. We aimed to assess the validity of utilizing clinical response to therapies specifically targeted to a suspected disease in clarifying variant pathogenicity.

Methods: Five families with disparate clinical presentations and different genetic diseases evaluated and treated in multiple diagnostic settings are summarized.

Results: Extended evaluations indicated possible genetic diagnoses and assigned candidate causal variants, but the cumulative clinical, biochemical, and molecular information in each instance was not completely consistent with the identified disease. Initiation of treatment specific to the suspected diagnoses in the affected individuals led to clinical improvement in all five families.

Conclusion: We propose that the effect of therapies that are specific and targeted to treatable genetic diseases embodies an in vivo physiological response and could be considered as additional criteria within the 2015 ACMG/AMP guidelines in determining genomic variant pathogenicity.

Covid-19 related publications can be found here.

Nanomedicine

Dos Santos Vieira B, Groenen K, 't Hoen PAC, Jacobsen A, Roos M, Kaliyaperumal R, Kersloot M, Cornet R, Schultze Kool L. Applying the FAIR data principles to the registry of vascular anomalies (VASCA). Stud Health Technol Inform 271:115-116, 2020. PMID: 32578552.

Background: Connecting currently existing, heterogeneous rare disease (RD) registries would greatly facilitate epidemiological and clinical research. To increase their interoperability, the European Union developed a set of Common Data Elements (CDEs) for RD registries. 

Objectives: To implement the CDEs and the FAIR data principles in the Registry of Vascular Anomalies (VASCA).

Methods: We created a semantic model for the CDE and transformed this into a Resource Description Framework (RDF) template. The electronic case report forms (eCRF) were mapped to the RDF template and published in a FAIR Data Point (FDP).

Results: The FAIR VASCA registry was successfully implemented using Castor EDC (Electronic Data Capture) software.

Conclusion: FAIR technology allows researchers to query and combine data from different registries in real-time.

de Haas P, Hendriks WJAJ, Lefeber DJ, Cambi A. Biological and technical challenges in unraveling the role of N-glycans in immune receptor regulation. Front Chem 8:55, 2020. PMID: 32117881.

N-glycosylation of membrane receptors is important for a wide variety of cellular processes. In the immune system, loss or alteration of receptor glycosylation can affect pathogen recognition, cell-cell interaction, and activation as well as migration. This is not only due to aberrant folding of the receptor, but also to altered lateral mobility or aggregation capacity. Despite increasing evidence of their biological relevance, glycosylation-dependent mechanisms of receptor regulation are hard to dissect at the molecular level. This is due to the intrinsic complexity of the glycosylation process and high diversity of glycan structures combined with the technical limitations of the current experimental tools. It is still challenging to precisely determine the localization and site-occupancy of glycosylation sites, glycan micro- and macro-heterogeneity at the individual receptor level as well as the biological function and specific interactome of receptor glycoforms. In addition, the tools available to manipulate N-glycans of a specific receptor are limited. Significant progress has however been made thanks to innovative approaches such as glycoproteomics, metabolic engineering, or chemoenzymatic labeling. By discussing examples of immune receptors involved in pathogen recognition, migration, antigen presentation, and cell signaling, this Mini Review will focus on the biological importance of N-glycosylation for receptor functions and highlight the technical challenges for examination and manipulation of receptor N-glycans.

Herzog R, van den Dries K, Cervero P, Linder S. Poji: a Fiji-based tool for analysis of podosomes and associated proteins. J Cell Sci 133:jcs238964, 2020. PMID: 32152182.

Podosomes are actin-based adhesion and invasion structures in a variety of cell types, with podosome-forming cells displaying up to several hundreds of these structures. Podosome number, distribution and composition can be affected by experimental treatments or during regular turnover, necessitating a tool that is able to detect even subtle differences in podosomal properties. Here, we present a Fiji-based macro code termed 'Poji' ('podosome analysis by Fiji'), which serves as an easy-to-use tool to characterize a variety of cellular and podosomal parameters, including area, fluorescence intensity, relative enrichment of associated proteins and radial podosome intensity profiles. This tool should be useful to gain more detailed insight into the regulation, architecture and functions of podosomes. Moreover, we show that Poji is easily adaptable for the analysis of invadopodia and associated extracellular matrix degradation, and likely also of other micron-size punctate structures. This article describes the workflow of the Poji macro, presents several examples of its applications, and also points out limitations, as well as respective solutions, and adaptable features to streamline the analysis.

Covid-19 related publications can be found here.

Vascular damage

Noz M, Bekkering S, Groh L, Nielen T, Lamfers E, Schlitzer A, El Messaoudi S, van Royen N, Huys E, Preijers F, Smeets E, Aarntzen E, Zhang B, Li Y, Bremmers M, van der Velden W, Dolstra H, Joosten LAB, Gomes ME, Netea MG, Riksen NP. Reprogramming of bone marrow myeloid progenitor cells in patients with severe coronary artery disease. Elife 9:60939, 2020. PMID 33168134.

Atherosclerosis is the major cause of cardiovascular disease (CVD). Monocyte-derived macrophages are the most abundant immune cells in atherosclerotic plaques. In patients with atherosclerotic CVD, leukocytes have a hyperinflammatory phenotype. We hypothesize that immune cell reprogramming in these patients occurs at the level of myeloid progenitors. We included 13 patients with coronary artery disease due to severe atherosclerosis and 13 subjects without atherosclerosis in an exploratory study. Cytokine production capacity after ex vivo stimulation of peripheral blood mononuclear cells (MNCs) and bone marrow MNCs was higher in patients with atherosclerosis. In BM-MNCs this was associated with increased glycolysis and oxidative phosphorylation. The BM composition was skewed towards myelopoiesis and transcriptome analysis of HSC/GMP cell populations revealed enrichment of neutrophil- and monocyte-related pathways. These results show that in patients with atherosclerosis, activation of innate immune cells occurs at the level of myeloid progenitors, which adds exciting opportunities for novel treatment strategies.

van der Heijden CDCC, Groh L, Keating ST, Kaffa C, Noz MP, Kersten S, van Herwaarden AE, Hoischen A, Joosten LA, Timmers HJ, Netea MG, Riksen NP. Catecholamines induce trained immunity In monocytes In vitro and In vivo. Circ Res 127:269-283, 2020. PMID 32241223.

Rationale: Exposure to high catecholamine levels is associated with inflammatory changes of myeloid cells and atherosclerosis, but the underlying mechanisms are only partly understood.

Objective: To investigate whether the proinflammatory effects of noradrenaline and adrenaline can, in part, be explained by the induction of an immunologic memory in innate immune cells, termed trained immunity.

Methods and results: In vitro, we exposed human primary monocytes to (nor)adrenaline for 24 hours, after which cells were rested and differentiated to macrophages over 5 days. After restimulation with lipopolysaccharide on day 6, (nor)adrenaline-exposed cells showed increased TNF-α (tumor necrosis factor-α) production. This coincided with an increase in glycolysis and oxidative phosphorylation measured with Seahorse technology on day 6 before restimulation. Inhibition of the β-adrenoreceptor-cAMP signaling pathway prevented the induction of training. In vivo, we studied the functional, transcriptional, and epigenetic impact of peak-wise exposure to high catecholamine levels on monocytes isolated from pheochromocytoma/paraganglioma (PHEO) patients. In PHEO patients (n=10), the peripheral blood cell composition showed a myeloid bias and an increase of the inflammatory CD14++CD16+ (cluster of differentiation) intermediate monocyte subset compared with controls with essential hypertension (n=14). Ex vivo production of proinflammatory cytokines was higher in PHEO patients. These inflammatory changes persisted for 4 weeks after surgical removal of PHEO. Transcriptome analysis of circulating monocytes at baseline showed various differentially expressed genes in inflammatory pathways in PHEO patients; epigenetic profiling of the promoters of these genes suggests enrichment of the transcriptionally permissive chromatin mark H3K4me3 (trimethylation of lysine 4 on histone H3), indicative of in vivo training.

Conclusions: Catecholamines induce long-lasting proinflammatory changes in monocytes in vitro and in vivo, indicating trained immunity. Our data contribute to the understanding of pathways driving inflammatory changes in conditions characterized by high catecholamine levels and propose that trained immunity underlies the increased cardiovascular event rate in PHEO patients.

Lemkes JS, Janssens GN, van der Hoeven NW, Jewbali LSD, Dubois EA, Meuwissen MM, Rijpstra TA, Bosker HA, Blans MJ, Bleeker GB, Baak RR, Vlachojannis GJ, Eikemans BJW, van der Harst P, van der Horst ICC, Voskuil M, van der Heijden JJ, Beishuizen A, Stoel M, Camaro C, van der Hoeven H, Henriques JP, Vlaar APJ, Vink MA, van den Bogaard B, Heestermans TACM, de Ruijter W, Delnoij TSR, Crijns HJGM, Jessurun GAJ, Oemrawsingh PV, Gosselink MTM, Plomp K, Magro M, Elbers PWG, Spoormans EM, van de Ven PM, Oudemans-van Straaten HM, van Royen N. Coronary Angiography After Cardiac Arrest Without ST Segment Elevation: One-Year Outcomes of the COACT Randomized Clinical Trial. JAMA Cardiol 5:1-8, 2020. PMID 32876654.

Importance:  Ischemic heart disease is a common cause of cardiac arrest. However, randomized data on long-term clinical outcomes of immediate coronary angiography and percutaneous coronary intervention (PCI) in patients successfully resuscitated from cardiac arrest in the absence of ST segment elevation myocardial infarction (STEMI) are lacking.

Objective:  To determine whether immediate coronary angiography improves clinical outcomes at 1 year in patients after cardiac arrest without signs of STEMI, compared with a delayed coronary angiography strategy.

Design, setting, and participants:  A prespecified analysis of a multicenter, open-label, randomized clinical trial evaluated 552 patients who were enrolled in 19 Dutch centers between January 8, 2015, and July 17, 2018. The study included patients who experienced out-of-hospital cardiac arrest with a shockable rhythm who were successfully resuscitated without signs of STEMI. Follow-up was performed at 1 year. Data were analyzed, using the intention-to-treat principle, between August 29 and October 10, 2019.

Interventions:  Immediate coronary angiography and PCI if indicated or coronary angiography and PCI if indicated, delayed until after neurologic recovery.

Main outcomes and measures:  Survival, myocardial infarction, revascularization, implantable cardiac defibrillator shock, quality of life, hospitalization for heart failure, and the composite of death or myocardial infarction or revascularization after 1 year.

Results:  At 1 year, data on 522 of 552 patients (94.6%) were available for analysis. Of these patients, 413 were men (79.1%); mean (SD) age was 65.4 (12.3) years. A total of 162 of 264 patients (61.4%) in the immediate angiography group and 165 of 258 patients (64.0%) in the delayed angiography group were alive (odds ratio, 0.90; 95% CI, 0.63-1.28). The composite end point of death, myocardial infarction, or repeated revascularization since the index hospitalization was met in 112 patients (42.9%) in the immediate group and 104 patients (40.6%) in the delayed group (odds ratio, 1.10; 95% CI, 0.77-1.56). No significant differences between the groups were observed for the other outcomes at 1-year follow-up. For example, the rate of ICD shocks was 20.4% in the immediate group and 16.2% in the delayed group (odds ratio, 1.32; 95% CI, 0.66-2.64).

Conclusions and relevance:  In this trial of patients successfully resuscitated after out-of-hospital cardiac arrest and without signs of STEMI, a strategy of immediate angiography was not found to be superior to a strategy of delayed angiography with respect to clinical outcomes at 1 year. Coronary angiography in this patient group can therefore be delayed until after neurologic recovery without affecting outcomes.

Covid-19 related publications can be found here.

Women's cancers

Khalil AA, Ilina O, Vasaturo A, Venhuizen J-H, Vullings M, Venhuizen V, Bilos A, Figdor CG, Span PN, Friedl P. Collective invasion induced by an autocrine purinergic loop through connexin-43 hemichannels. J Cell Biol 219:e201911120, 2020. PMID 32777015.

Progression of epithelial cancers predominantly proceeds by collective invasion of cell groups with coordinated cell-cell junctions and multicellular cytoskeletal activity. Collectively invading breast cancer cells express the gap junction protein connexin-43 (Cx43), yet whether Cx43 regulates collective invasion remains unclear. We here show that Cx43 mediates gap-junctional coupling between collectively invading breast cancer cells and, via hemichannels, adenosine nucleotide/nucleoside release into the extracellular space. Using molecular interference and rescue strategies, we identify that Cx43 hemichannel function, but not intercellular communication, induces leader cell activity and collective migration through the engagement of the adenosine receptor 1 (ADORA1) and AKT signaling. Accordingly, pharmacological inhibition of ADORA1 or AKT signaling caused leader cell collapse and halted collective invasion. ADORA1 inhibition further reduced local invasion of orthotopic mammary tumors in vivo, and joint up-regulation of Cx43 and ADORA1 in breast cancer patients correlated with decreased relapse-free survival. This identifies autocrine purinergic signaling, through Cx43 hemichannels, as a critical pathway in leader cell function and collective invasion.

Reijnen C, Gogou E, Visser NCM , Engerud H, Ramjith J, van der Putten LJ , van de Vijver K, Santacana M, Bronsert P, Bulten J, Krakstad C, Bednarikova M, Hausnerova J, van der Wurff AAM, Matias-Guiu X, Amant F, ENITEC Consortium, Massuger LFAG, Snijders MPLM, Küsters-Vandevelde HVN, Lucas PJF, Pijnenborg JMA. Preoperative risk stratification in endometrial cancer (ENDORISK) by a Bayesian network model: A development and validation study. PLoS Med 17:e1003111, 2020. PMID 32413043.

Background: Bayesian networks (BNs) are machine-learning-based computational models that visualize causal relationships and provide insight into the processes underlying disease progression, closely resembling clinical decision-making. Preoperative identification of patients at risk for lymph node metastasis (LNM) is challenging in endometrial cancer, and although several biomarkers are related to LNM, none of them are incorporated in clinical practice. The aim of this study was to develop and externally validate a preoperative BN to predict LNM and outcome in endometrial cancer patients.

Methods and findings: Within the European Network for Individualized Treatment of Endometrial Cancer (ENITEC), we performed a retrospective multicenter cohort study including 763 patients, median age 65 years (interquartile range [IQR] 58-71), surgically treated for endometrial cancer between February 1995 and August 2013 at one of the 10 participating European hospitals. A BN was developed using score-based machine learning in addition to expert knowledge. Our main outcome measures were LNM and 5-year disease-specific survival (DSS). Preoperative clinical, histopathological, and molecular biomarkers were included in the network. External validation was performed using 2 prospective study cohorts: the Molecular Markers in Treatment in Endometrial Cancer (MoMaTEC) study cohort, including 446 Norwegian patients, median age 64 years (IQR 59-74), treated between May 2001 and 2010; and the PIpelle Prospective ENDOmetrial carcinoma (PIPENDO) study cohort, including 384 Dutch patients, median age 66 years (IQR 60-73), treated between September 2011 and December 2013. A BN called ENDORISK (preoperative risk stratification in endometrial cancer) was developed including the following predictors: preoperative tumor grade; immunohistochemical expression of estrogen receptor (ER), progesterone receptor (PR), p53, and L1 cell adhesion molecule (L1CAM); cancer antigen 125 serum level; thrombocyte count; imaging results on lymphadenopathy; and cervical cytology. In the MoMaTEC cohort, the area under the curve (AUC) was 0.82 (95% confidence interval [CI] 0.76-0.88) for LNM and 0.82 (95% CI 0.77-0.87) for 5-year DSS. In the PIPENDO cohort, the AUC for 5-year DSS was 0.84 (95% CI 0.78-0.90). The network was well-calibrated. In the MoMaTEC cohort, 249 patients (55.8%) were classified with <5% risk of LNM, with a false-negative rate of 1.6%. A limitation of the study is the use of imputation to correct for missing predictor variables in the development cohort and the retrospective study design.

Conclusions: In this study, we illustrated how BNs can be used for individualizing clinical decision-making in oncology by incorporating easily accessible and multimodal biomarkers. The network shows the complex interactions underlying the carcinogenetic process of endometrial cancer by its graphical representation. A prospective feasibility study will be needed prior to implementation in the clinic.

Zhang Y, Tang C, Span PN, Rowan AE, Aalders TW, Schalken JA, Adema GJ, Kouwer PHJ, Zegers MMP, Ansems M. Polyisocyanide hydrogels as a tunable platform for mammary gland organoid formation. Adv Sci (Weinh) 7:2001797, 2020. PMID 32999851.

In the last decade, organoid technology has developed as a primary research tool in basic biological and clinical research. The reliance on poorly defined animal-derived extracellular matrix, however, severely limits its application in regenerative and translational medicine. Here, a well-defined, synthetic biomimetic matrix based on polyisocyanide (PIC) hydrogels that support efficient and reproducible formation of mammary gland organoids (MGOs) in vitro is presented. Only decorated with the adhesive peptide RGD for cell binding, PIC hydrogels allow MGO formation from mammary fragments or from purified single mammary epithelial cells. The cystic organoids maintain their capacity to branch for over two months, which is a fundamental and complex feature during mammary gland development. It is found that small variations in the 3D matrix give rise to large changes in the MGO: the ratio of the main cell types in the MGO is controlled by the cell-gel interactions via the cell binding peptide density, whereas gel stiffness controls colony formation efficiency, which is indicative of the progenitor density. Simple hydrogel modifications will allow for future introduction and customization of new biophysical and biochemical parameters, making the PIC platform an ideal matrix for in depth studies into organ development and for application in disease models.

Covid-19 related publications can be found here.

Rare cancers

Rabold K, Aschenbrenner A, Thiele C, Boahen CK, Schiltmans A, Smit JWA, Schultze JL, Netea MG, Adema GJ, Netea-Maier RT. Enhanced lipid biosynthesis in human tumor-induced macrophages contributes to their protumoral characteristics. J Immunother Cancer 8:e000638, 2020. PMID 32943450.

Background: Tumor-associated macrophages (TAMs) are key components of the tumor microenvironment (TME) in non-medullary thyroid carcinoma (TC) and neuroblastoma (NB), being associated with a poor prognosis for patients. However, little is known about how tumors steer the specific metabolic phenotype and function of TAMs.

Methods: In a human coculture model, transcriptome, metabolome and lipidome analysis were performed on TC-induced and NB-induced macrophages. The metabolic shift was correlated to functional readouts, such as cytokine production and reactive oxygen species (ROS) production, including pharmacological inhibition of metabolic pathways.

Results: Based on transcriptome and metabolome analysis, we observed a strong upregulation of lipid biosynthesis pathways in TAMs. Subsequently, lipidome analysis revealed that tumor-induced macrophages have an increased total lipid content and enriched levels of intracellular lipids, especially phosphoglycerides and sphingomyelins. Strikingly, this metabolic shift in lipid synthesis contributes to their protumoral functional characteristics: blocking key enzymes of lipid biosynthesis in the tumor-induced macrophages reversed the increased inflammatory cytokines and the capacity to produce ROS, two well-known protumoral factors in the TME.

Conclusions: Taken together, our data show that tumor cells can stimulate lipid biosynthesis in macrophages to induce protumoral cytokine and ROS responses and advocate lipid biosynthesis as a potential therapeutic target to reprogram the TME.

Weidema ME, van de Geer E, Koelsche C, Desar I, Kemmeren P, Hillebrandt-Roeffen MHS, Ho VKY, Group P, van der Graaf WTA, Versleijen-Jonkers YMH, von Deimling A,, Flucke UE. DNA methylation profiling identifies distinct clusters in angiosarcomas. Clin Cancer Res 26:93-100, 2020. PMID 31562204.

Purpose: DNA methylation profiling has previously uncovered biologically and clinically meaningful subgroups within many tumor types, but was not yet performed in angiosarcoma. Angiosarcoma is a rare sarcoma with very heterogeneous clinical presentations, which may be based on differences in biological background. In this exploratory study, DNA methylation profiling of 36 primary angiosarcoma samples from visceral, deep soft tissue, radiation-induced, and UV-induced localizations was performed.

Experimental design: Primary angiosarcoma formalin-fixed paraffin-embedded samples from visceral, soft tissue, radiation-induced, and UV-induced origin were collected from a nationwide search for angiosarcoma in the Netherlands. DNA was extracted for methylation profiling with the Illumina Infinium MethylationEPIC array. Quality control assessment and unsupervised hierarchical clustering were performed. Copy-number profiles were generated and analyzed for chromosomal stability. Clinical data were obtained from the Netherlands Cancer Registry.

Results: DNA methylation profiling by unsupervised hierarchical clustering of 36 angiosarcoma samples (6 visceral, 5 soft tissue, 14 radiation-induced, 11 UV-induced) revealed two main clusters (A and B), which were divided into four subclusters. The clusters largely corresponded with clinical subtypes, showing enrichment of UV-induced cases in cluster A1 and radiation-induced cases in cluster A2. Visceral and soft tissue cases almost exclusively fell into cluster B. Cluster A showed significantly increased chromosomal instability and better overall survival (22 vs. 6 months, P = 0.046) compared with cluster B.

Conclusions: In this novel methylation profiling study, we demonstrated for the first time four different angiosarcoma clusters. These clusters correlated with clinical subtype, overall survival, and chromosomal stability.

Covid-19 related publications can be found here.

Renal disorders

Miesen L, Eymael J, Sharma S, Loeven MA, Willemsen B, Bakker-van Bebber M, Mooren F, Meyer-Schwesinger C, Dijkman H, Wetzels JFM, Jansen J, van der Vlag J, Smeets B. Inhibition of mTOR delayed but could not prevent experimental collapsing focal segmental glomerulosclerosis. Sci Rep 10:8580, 2020. PMID 32444668.

Anti-Thy1.1 transgenic mice develop glomerular lesions that mimic collapsing focal segmental glomerulosclerosis (FSGS) in humans with collapse of the glomerular tuft and marked hyperplasia of the parietal epithelial cells (PECs). Immunostaining of phosphor-S6 ribosomal protein (pS6RP) revealed high mTOR activity in PECs of the FSGS lesions of these mice. In this study we questioned whether the mTOR inhibitor rapamycin (sirolimus) could attenuate the development and progression of glomerulosclerotic lesions in the anti-Thy1.1 transgenic mice. We observed reduced mTOR signalling and proliferation in human parietal epithelial cells after rapamycin treatment. Experiments with anti-Thy1.1. mice showed that early treatment with sirolimus reduced the development of glomerular lesions and glomerular cell proliferation at day 4. Levels of albuminuria, podocyte injury and podocyte number were similar in the sirolimus and vehicle treated groups. The initial beneficial effects of sirolimus treatment were not observed at day 7. Late sirolimus treatment did not reduce albuminuria or the progression of glomerulosclerosis. Taken together, rapamycin attenuated PEC proliferation and the formation of early FSGS lesions in experimental FSGS and reduced human PEC proliferation in vitro. However, the initial inhibition of PEC proliferation did not translate into a decline of albuminuria nor in a sustained reduction in sclerotic lesions.

Ter Braake AD, Smit AE, Bos C, van Herwaarden AE, Alkema W, van Essen HW, Bravenboer N, Vervloet MG, Hoenderop JGJ, de Baaij JHF. Magnesium prevents vascular calcification in Klotho deficiency. Kidney Int 97:487-501, 2020. PMID: 31866113.

Anti-Thy1.1 transgenic mice develop glomerular lesions that mimic collapsing focal segmental glomerulosclerosis (FSGS) in humans with collapse of the glomerular tuft and marked hyperplasia of the parietal epithelial cells (PECs). Immunostaining of phosphor-S6 ribosomal protein (pS6RP) revealed high mTOR activity in PECs of the FSGS lesions of these mice. In this study we questioned whether the mTOR inhibitor rapamycin (sirolimus) could attenuate the development and progression of glomerulosclerotic lesions in the anti-Thy1.1 transgenic mice. We observed reduced mTOR signalling and proliferation in human parietal epithelial cells after rapamycin treatment. Experiments with anti-Thy1.1. mice showed that early treatment with sirolimus reduced the development of glomerular lesions and glomerular cell proliferation at day 4. Levels of albuminuria, podocyte injury and podocyte number were similar in the sirolimus and vehicle treated groups. The initial beneficial effects of sirolimus treatment were not observed at day 7. Late sirolimus treatment did not reduce albuminuria or the progression of glomerulosclerosis. Taken together, rapamycin attenuated PEC proliferation and the formation of early FSGS lesions in experimental FSGS and reduced human PEC proliferation in vitro. However, the initial inhibition of PEC proliferation did not translate into a decline of albuminuria nor in a sustained reduction in sclerotic lesions.

Freriksen JJM, Meijerhof M, van Drongelen J, Drenth JPH, Burger DM, Russel FGM, Colbers A, Greupink R. Transfer of daclatasvir and sofosbuvir's main metabolite GS-331007 across the human placenta ex vivo. Am J Obstet Gynecol 223:941-943, 2020. PMID 32877661.

The treatment of hepatitis C virus (HCV) infection during pregnancy is mainly focused on maternal cure, with the secondary aim of also preventing vertical transmission to the fetus. Direct-acting antivirals (DAAs) are commonly being prescribed to nonpregnant patients, but a lack of data on the pharmacokinetics, safety, and efficacy of DAAs hampers their use in pregnant patients. It has been hypothesized that ribavirin-free maternal treatment regimens with DAAs could be appropriate if it can be shown that treatment during pregnancy does not cause reproductive toxic adverse effect. We provide data on the placental transfer of DAAs by describing the placental transfer of sofosbuvir’s main metabolite, GS-331007, and daclatasvir in the ex vivo perfused human placenta.

Covid-19 related publications can be found here.