Publications by authors named "Marie Follo"

111 Publications

Human Primary Breast Cancer Stem Cells Are Characterized by Epithelial-Mesenchymal Plasticity.

Int J Mol Sci 2021 Feb 11;22(4). Epub 2021 Feb 11.

German Cancer Consortium (DKTK), DKFZ, 69120 Heidelberg, Germany.

Triple-negative breast cancer (TNBC) is one of the most aggressive subtypes of breast cancer, with only limited treatment options available. Recently, cancer stem cells (CSCs) have emerged as the potential drivers of tumor progression due to their ability to both self-renew and give rise to differentiated progeny. The CSC state has been linked to the process of epithelial-mesenchymal transition (EMT) and to the highly flexible state of epithelial-mesenchymal plasticity (EMP). We aimed to establish primary breast cancer stem cell (BCSC) cultures isolated from TNBC specimens. These cells grow as tumor spheres under anchorage-independent culture conditions in vitro and reliably form tumors in mice when transplanted in limiting dilutions in vivo. The BCSC xenograft tumors phenocopy the original patient tumor in architecture and gene expression. Analysis of an EMT-related marker profile revealed the concomitant expression of epithelial and mesenchymal markers suggesting an EMP state for BCSCs of TNBC. Furthermore, BCSCs were susceptible to stimulation with the EMT inducer TGF-β1, resulting in upregulation of mesenchymal genes and enhanced migratory abilities. Overall, primary BCSC cultures are a promising model close to the patient that can be used both in vitro and in vivo to address questions of BCSC biology and evaluate new treatment options for TNBC.
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http://dx.doi.org/10.3390/ijms22041808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7918351PMC
February 2021

Antimicrobial Photoinactivation of In Situ Oral Biofilms by Visible Light Plus Water-Filtered Infrared A and Tetrahydroporphyrin-tetratosylate (THPTS).

Microorganisms 2021 Jan 11;9(1). Epub 2021 Jan 11.

Department of Operative Dentistry and Periodontology, Medical Center, University of Freiburg, 79106 Freiburg, Germany.

The aim of this study was to examine the effect of aPDT with visual light (VIS) + water-filtered infrared A (wIRA) as a light source, and tetrahydroporphyrin-tetratosylate (THPTS) as a photosensitizer on in situ initial and mature oral biofilms. The samples were incubated, ex situ, with THPTS for two minutes, followed by irradiation with 200 mW cm - 2 VIS + wIRA for five minutes at 37 °C. The adherent microorganisms were quantified, and the biofilm samples were visualized using live/dead staining and confocal laser scanning microscopy (CLSM). The THPTS-mediated aPDT resulted in significant decreases in both the initially adherent microorganisms and the microorganisms in the mature oral biofilms, in comparison to the untreated control samples (>99.99% each; = 0.018 and = 0.0066, respectively). The remaining vital bacteria significantly decreased in the aPDT-treated biofilms during initial adhesion (vitality rate 9.4% vs. 71.2% untreated control, 17.28% CHX). Of the mature biofilms, 25.67% remained vital after aPDT treatment (81.97% untreated control, 16.44% CHX). High permeability of THPTS into deep layers could be shown. The present results indicate that the microbial reduction in oral initial and mature oral biofilms resulting from aPDT with VIS + wIRA in combination with THPTS has significant potential for the treatment of oral biofilm-associated diseases.
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http://dx.doi.org/10.3390/microorganisms9010145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7827502PMC
January 2021

Longitudinal analysis of cell-free mutated KRAS and CA 19-9 predicts survival following curative resection of pancreatic cancer.

BMC Cancer 2021 Jan 11;21(1):49. Epub 2021 Jan 11.

Department of Medicine I (Hematology, Oncology and Stem Cell Transplantation), Freiburg University Medical Center, Freiburg, Germany.

Background: Novel biomarkers and molecular monitoring tools hold potential to improve outcome for patients following resection of pancreatic ductal adenocarcinoma (PDAC). We hypothesized that the combined longitudinal analysis of mutated cell-free plasma KRAS (cfKRAS) and CA 19-9 during adjuvant treatment and follow-up might more accurately predict disease course than hitherto available parameters.

Methods: Between 07/2015 and 10/2018, we collected 134 plasma samples from 25 patients after R0/R1-resection of PDAC during adjuvant chemotherapy and post-treatment surveillance at our institution. Highly sensitive discriminatory multi-target ddPCR assays were employed to screen plasma samples for cfKRAS. cfKRAS and CA 19-9 dynamics were correlated with recurrence-free survival (RFS) and overall survival (OS). Patients were followed-up until 01/2020.

Results: Out of 25 enrolled patients, 76% had undergone R0 resection and 48% of resected PDACs were pN0. 17/25 (68%) of patients underwent adjuvant chemotherapy. Median follow-up was 22.0 months, with 19 out of 25 (76%) patients relapsing during study period. Median RFS was 10.0 months, median OS was 22.0 months. Out of clinicopathologic variables, only postoperative CA 19-9 levels and administration of adjuvant chemotherapy correlated with survival endpoints. cfKRAS was detected in 12/25 (48%) of patients, and detection of high levels inversely correlated with survival endpoint. Integration of cfKRAS and CA 19-9 levels outperformed either individual marker. cfKRAS outperformed CA 19-9 as dynamic marker since increase during adjuvant chemotherapy and follow-up was highly predictive of early relapse and poor OS.

Conclusions: Integrated analysis of cfKRAS and CA 19-9 levels is a promising approach for molecular monitoring of patients following resection of PDAC. Larger prospective studies are needed to further develop this approach and dissect each marker's specific potential.
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http://dx.doi.org/10.1186/s12885-020-07736-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7802224PMC
January 2021

Personalized Treatment Selection and Disease Monitoring Using Circulating Tumor DNA Profiling in Real-World Cancer Patient Management.

Diagnostics (Basel) 2020 Aug 2;10(8). Epub 2020 Aug 2.

Department Medicine I, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany.

Background: Circulating tumor DNA (ctDNA) in the blood plasma of cancer patients is an emerging biomarker used across oncology, facilitating noninvasive disease monitoring and genetic profiling at various disease milestones. Digital droplet PCR (ddPCR) technologies have demonstrated high sensitivity and specificity for robust ctDNA detection at relatively low costs. Yet, their value for ctDNA-based management of a broad population of cancer patients beyond clinical trials remains elusive.

Methods: We developed mutation-specific ddPCR assays that were optimized for their use in real-world cancer management, covering 12 genetic aberrations in common cancer genes, such as , , , , and . We assessed the limit of detection (LOD) and the limit of blank (LOB) for each assay and validated their performance for ctDNA detection using matched tumor sequencing.

Results: We applied our custom ddPCR assays to 352 plasma samples from 96 patients with solid tumors. Mutation detection in plasma was highly concordant with tumor sequencing, demonstrating high sensitivity and specificity across all assays. In 20 cases, radiographic cancer progression was mirrored by an increase of ctDNA concentrations or the occurrence of novel mutations in plasma. Moreover, ctDNA profiling at diagnosis and during disease progression reflected personalized treatment selection through the identification of actionable gene targets in 20 cases.

Conclusion: Collectively, our work highlights the potential of ctDNA assessment by sensitive ddPCR for accurate disease monitoring, robust identification of resistance mutations, and upfront treatment selection in patients with solid tumors. We envision an increasing future role for ctDNA profiling within personalized cancer management in daily clinical routine.
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http://dx.doi.org/10.3390/diagnostics10080550DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7459590PMC
August 2020

FAK inhibition radiosensitizes pancreatic ductal adenocarcinoma cells in vitro.

Strahlenther Onkol 2021 Jan 23;197(1):27-38. Epub 2020 Jul 23.

Department of Radiation Oncology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Introduction: Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase protein frequently overexpressed in cancer and has been linked to an increase in the stem cell population of tumors, resistance to therapy, and metastatic spread. Pharmacological FAK inhibition in pancreatic cancer has received increased attention over the last few years, either alone or in combination with other therapeutics including chemotherapy and immunotherapy. However, its prognostic value and its role in radioresistance of pancreatic ducal adenocarcinoma (PDAC) is unknown.

Methods And Materials: Using the TCGA and GTEx databases, we investigated the genetic alterations and mRNA expression levels of PTK2 (the encoding-gene for FAK) in normal pancreatic tissue and pancreatic cancer and its impact on patient survival. Furthermore, we evaluated the expression of FAK and its tyrosine domain Ty-397 in three pancreatic cancer cell lines. We went further and evaluated the role of a commercial FAK tyrosine kinase inhibitor VS-4718 on the viability and radiosensitization of the pancreatic cell lines as well as its effect on the extracellular matrix (ECM) production from the pancreatic stellate cells. Furthermore, we tested the effect of combining radiation with VS-4718 in a three-dimensional (3D) multicellular pancreatic tumor spheroid model.

Results: A database analysis revealed a relevant increase in genetic alterations and mRNA expression of the PTK2 in PDAC, which were associated with lower progression-free survival. In vitro, there was only variation in the basal phosphorylation level of FAK in cell lines. VS-4718 radiosensitized pancreatic cell lines only in the presence of ECM-producing pancreatic stellate cells and markedly reduced the ECM production in the stromal cells. Finally, using a 3D multicellular tumor model, the combination of VS-4718 and radiotherapy significantly reduced the growth of tumor aggregates.

Conclusion: Pharmacological inhibition of FAK in pancreatic cancer could be a novel therapeutic strategy as our results show a radiosensitization effect of VS-4718 in vitro in a multicellular 2D- and in a 3D-model of pancreatic cancer.
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http://dx.doi.org/10.1007/s00066-020-01666-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7801360PMC
January 2021

Bile acids regulate intestinal antigen presentation and reduce graft-versus-host disease without impairing the graft-versus-leukemia effect.

Haematologica 2020 Jul 16. Epub 2020 Jul 16.

Department of Medicine I, Medical Center - University of Freiburg, Germany;

Acute graft-versus-host disease causes significant mortality in patients undergoing allogeneic hematopoietic cell transplantation. Immunosuppressive treatment for graft-versus-host disease can impair the beneficial graft-versus-leukemia effect and facilitate malignancy relapse. Therefore, novel approaches that protect and regenerate injured tissues without impeding the donor immune system are needed. Bile acids regulate multiple cellular processes and are in close contact with the intestinal epithelium, a major target of acute graft-versus-host disease. Here, we found that the bile acid pool is reduced following graft-versus-host disease induction in a preclinical model. We evaluated the efficacy of bile acids to protect the intestinal epithelium without reducing anti-tumor immunity. We observed that application of bile acids decreased cytokine-induced cell death in intestinal organoids and cell lines. Systemic prophylactic administration of tauroursodeoxycholic acid, the most potent compound in our in vitro studies, reduced graft-versus-host disease severity in three different murine transplantation models. This effect was mediated by decreased activity of the antigen presentation machinery and subsequent prevention of apoptosis of the intestinal epithelium. Moreover, bile acid administration did not alter the bacterial composition in the intestine suggesting that its effects are cell-specific and independent of the microbiome. Treatment of human and murine leukemic cell lines with tauroursodeoxycholic acid did not interfere with the expression of antigen presentation-related molecules. Systemic T cell expansion and especially their cytotoxic capacity against leukemic cells remained intact. This study establishes a role for bile acids in the prevention of acute graft-versus-host disease without impairing the graft-versus-leukemia effect. In particular, we provide a scientific rationale for the systematic use of tauroursodeoxycholic acid in patients undergoing allogeneic hematopoietic cell transplantation.
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http://dx.doi.org/10.3324/haematol.2019.242990DOI Listing
July 2020

Development and Clinical Validation of Discriminatory Multitarget Digital Droplet PCR Assays for the Detection of Hot Spot KRAS and NRAS Mutations in Cell-Free DNA.

J Mol Diagn 2020 07 4;22(7):943-956. Epub 2020 May 4.

Department of Medicine I (Hematology, Oncology and Stem Cell Transplantation), Freiburg University Medical Center, Freiburg, Germany; German Cancer Consortium (DKTK) partner site Freiburg, Heidelberg, Germany; Department of Medical Oncology and Hematology, Zurich University Hospital, Zurich, Switzerland. Electronic address:

Detection and quantification of tumor-derived KRAS and NRAS mutations in plasma cell-free DNA (cfDNA) holds great potential for cancer diagnostics and treatment response monitoring. Because of high sensitivity, specificity, robustness, and affordability, digital droplet PCR (ddPCR) is ideally suited for this application but requires discriminatory multiplexing when used as screening assay. We therefore designed, optimized, and clinically validated mutation-specific locked nucleic acid-based ddPCR assays for 14 commonly occurring KRAS and NRAS mutations and assembled these assays into seven discriminatory multitarget screening assays covering two to six single-nucleotide variants each. Limit of detection, limit of blank, and interassay accuracy were determined. Assay performance and suitability for screening in cfDNA were validated with plasma samples from a clinically fully characterized cohort of pancreatic cancer patients and healthy controls. Limits of detection for single-target assays were between 0.0015% and 0.069% variant allele fraction, and between 0.022% and 0.16% for multitarget assays. Dilution linearity and interassay accuracy were excellent throughout (r > 0.99). Multitarget assay screening of cfDNA extracted from pancreatic cancer patients with unknown KRAS mutational status correctly identified single-nucleotide variants in 45 of 45 (100%) of tumor-derived cell-free DNA-positive samples. In summary, we herein present and clinically validate generic single-target and discriminatory multitarget ddPCR assays for KRAS and NRAS hot spot mutations with broad applicability for clinical and translational research.
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http://dx.doi.org/10.1016/j.jmoldx.2020.04.206DOI Listing
July 2020

Loss of the Fanconi anemia-associated protein NIPA causes bone marrow failure.

J Clin Invest 2020 06;130(6):2827-2844

Department of Internal Medicine I, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Inherited bone marrow failure syndromes (IBMFSs) are a heterogeneous group of disorders characterized by defective hematopoiesis, impaired stem cell function, and cancer susceptibility. Diagnosis of IBMFS presents a major challenge due to the large variety of associated phenotypes, and novel, clinically relevant biomarkers are urgently needed. Our study identified nuclear interaction partner of ALK (NIPA) as an IBMFS gene, as it is significantly downregulated in a distinct subset of myelodysplastic syndrome-type (MDS-type) refractory cytopenia in children. Mechanistically, we showed that NIPA is major player in the Fanconi anemia (FA) pathway, which binds FANCD2 and regulates its nuclear abundance, making it essential for a functional DNA repair/FA/BRCA pathway. In a knockout mouse model, Nipa deficiency led to major cell-intrinsic defects, including a premature aging phenotype, with accumulation of DNA damage in hematopoietic stem cells (HSCs). Induction of replication stress triggered a reduction in and functional decline of murine HSCs, resulting in complete bone marrow failure and death of the knockout mice with 100% penetrance. Taken together, the results of our study add NIPA to the short list of FA-associated proteins, thereby highlighting its potential as a diagnostic marker and/or possible target in diseases characterized by hematopoietic failure.
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http://dx.doi.org/10.1172/JCI126215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7260023PMC
June 2020

Existence of reprogrammed lymphoma stem cells in a murine ALCL-like model.

Leukemia 2020 12 17;34(12):3242-3255. Epub 2020 Mar 17.

Department of Medicine I, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106, Freiburg, Germany.

While cancer stem cells are well established in certain hematologic and solid malignancies, their existence in T cell lymphoma is unclear and the origin of disease is not fully understood. To examine the existence of lymphoma stem cells, we utilized a mouse model of anaplastic large cell lymphoma. Established NPM-ALK lymphomas contained heterogeneous cell populations ranging from mature T cells to undifferentiated hematopoietic stem cells. Interestingly, CD4/CD8 double negative (DN) lymphoma cells aberrantly expressed the T cell receptor α/β chain. Serial transplantation of sorted CD4/CD8 and DN lymphoma subpopulations identified lymphoma stem cells within the DN3/DN4 T cell population, whereas all other subpopulations failed to establish serial lymphomas. Moreover, transplanted lymphoma DN3/DN4 T cells were able to differentiate and gave rise to mature lymphoma T cells. Gene expression analyses unmasked stem-cell-like transcriptional regulation of the identified lymphoma stem cell population. Furthermore, these lymphoma stem cells are characterized by low CD30 expression levels, which might contribute to limited long-term therapeutic success in patients treated with anti-CD30-targeted therapies. In summary, our results highlight the existence of a lymphoma stem cell population in a NPM-ALK-driven CD30 mouse model, thereby giving the opportunity to test innovative treatment strategies developed to eradicate the origin of disease.
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http://dx.doi.org/10.1038/s41375-020-0789-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7685983PMC
December 2020

Lack of a skeletal muscle phenotype in adult human bone marrow stromal cells following xenogeneic-free expansion.

Stem Cell Res Ther 2020 02 22;11(1):79. Epub 2020 Feb 22.

G.E.R.N. Center for Tissue Replacement, Regeneration and Neogenesis, Department of Orthopaedics and Trauma Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Background: Many studies have elegantly shown that murine and rat bone marrow-derived mesenchymal stromal cells (bmMSCs) contribute to muscle regeneration and improve muscle function. Yet, the ability of transplanted human bmMSCs to manifest myogenic potential shows conflicting results. While human adipose- and umbilical cord-derived MSCs can be differentiated into a skeletal muscle phenotype using horse serum (HS), bmMSCs have only been shown to differentiate towards the skeletal muscle lineage using a complex mixture of cytokines followed by transfection with notch intracellular domain.

Methods: Since xenogeneic-free growth supplements are increasingly being used in the expansion of bmMSCs in clinical trials, we investigated the effects of human plasma and platelet lysate (P/PL) on the expression of neuromuscular markers and whether P/PL-expanded human bmMSCs could be differentiated towards a skeletal myogenic phenotype. Neuromuscular markers were measured using the highly sensitive droplet digital polymerase chain reaction for measuring the expression of Myf5, MyoD, MyoG, ACTA1, Desmin, GAP-43, and Coronin 1b transcripts, by performing immunofluorescence for the expression of Desmin, GAP-43, and MEF2, and flow cytometry for the expression of CD56/neural cell adhesion molecule (NCAM).

Results: Despite that bmMSCs expressed the myogenic regulatory factor (MRF) MEF2 after expansion in P/PL, bmMSCs cultured under such conditions did not express other essential MRFs including Myf5, MyoD, MyoG, or ACTA1 needed for myogenesis. Moreover, HS did not induce myogenesis of bmMSCs and hence did not induce the expression of any of these myogenic markers. P/PL, however, did lead to a significant increase in neurogenic GAP-43, as well as Desmin expression, and resulted in a high baseline expression of the neurogenic gene Coronin 1b which was sustained under further P/PL or HS culture conditions. Fetal bovine serum resulted in equally high levels of GAP-43 and Coronin 1b. Moreover, the proportion of CD56/NCAM-positive bmMSCs cultured in P/PL was 5.9 ± 2.1.

Conclusions: These data suggest that P/PL may prime a small portion of bmMSCs towards an early neural precursor cell type. Collectively, this shows that P/PL partially primes the cells towards a neurogenic phenotype, but does not prime adult human bmMSCs towards the skeletal muscle lineage.
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http://dx.doi.org/10.1186/s13287-020-1587-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7036219PMC
February 2020

TCL1 transgenic mice as a model for CD49d-high chronic lymphocytic leukemia.

Leukemia 2020 09 21;34(9):2498-2502. Epub 2020 Feb 21.

Department of Internal Medicine III with Hematology, Medical Oncology, Hemostaseology, Infectiology and Rheumatology, Oncologic Center, Salzburg Cancer Research Institute-Laboratory for Immunological and Molecular Cancer Research (SCRI-LIMCR), Paracelsus Medical University, Salzburg, Austria.

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http://dx.doi.org/10.1038/s41375-020-0759-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7449868PMC
September 2020

γδ T-cell Receptors Derived from Breast Cancer-Infiltrating T Lymphocytes Mediate Antitumor Reactivity.

Cancer Immunol Res 2020 04 4;8(4):530-543. Epub 2020 Feb 4.

Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands.

γδ T cells in human solid tumors remain poorly defined. Here, we describe molecular and functional analyses of T-cell receptors (TCR) from tumor-infiltrating γδ T lymphocytes (γδ TIL) that were in direct contact with tumor cells in breast cancer lesions from archival material. We observed that the majority of γδ TILs harbored a proinflammatory phenotype and only a minority associated with the expression of IL17. We characterized TCRγ or TCRδ chains of γδ TILs and observed a higher proportion of Vδ2 T cells compared with other tumor types. By reconstructing matched Vδ2 TCRγ and TCRδ pairs derived from single-cell sequencing, our data suggest that γδ TILs could be active against breast cancer and other tumor types. The reactivity pattern against tumor cells depended on both the TCRγ and TCRδ chains and was independent of additional costimulation through other innate immune receptors. We conclude that γδ TILs can mediate tumor reactivity through their individual γδ TCR pairs and that engineered T cells expressing TCRγ and δ chains derived from γδ TILs display potent antitumor reactivity against different cancer cell types and, thus, may be a valuable tool for engineering immune cells for adoptive cell therapies.
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http://dx.doi.org/10.1158/2326-6066.CIR-19-0513DOI Listing
April 2020

CCL5 mediates target-kinase independent resistance to FLT3 inhibitors in FLT3-ITD-positive AML.

Mol Oncol 2020 04 13;14(4):779-794. Epub 2020 Feb 13.

Department of Medicine I (Hematology, Oncology and Stem Cell Transplantation), Medical Center, Faculty of Medicine, University of Freiburg, Germany.

FLT3-ITD tyrosine kinase inhibitors (TKI) show limited clinical activity in acute myeloid leukemia (AML) due to emerging resistance. TKI resistance is mediated by secondary FLT3-ITD mutations only in a minority of cases. We hypothesize that the cytokine CCL5 protects AML cells from TKI-mediated cell death and contributes to treatment resistance. We generated PKC412- and sorafenib-resistant MOLM-13 cell lines as an in vitro model to study TKI resistance in AML. Increased CCL5 levels were detected in supernatants from PKC412-resistant cell lines compared to TKI-sensitive cells. Moreover, CCL5 treatment of TKI-sensitive cells induced resistance to PKC412. In resistant cell lines with high CCL5 release, we observed a significant downregulation of the CCL5-receptor CCR5 and CXCR4. In these cell lines, TKI resistance could be partly overcome by addition of the CXCR4-receptor antagonist plerixafor. Microarray and intracellular flow cytometry analyses revealed increased p-Akt or p-Stat5 levels in PKC412-resistant cell lines releasing high amounts of CCL5. Treatment with the CXCR4 antagonist plerixafor, αCCL5, or CCR5-targeting siRNA led to a decrease of p-Akt-positive cells. Transient transfection of sensitive MOLM-13 cells with a CCL5-encoding vector mediated resistance against PKC412 and led to an increase in p-Akt-positive and p-Stat5-positive cells. Isolated AML blasts from patients treated with PKC412 revealed that CCL5 transcript levels increase significantly at relapse. Taken together, our findings indicate that CCL5 mediates resistance to FLT3-TKIs in FLT3-ITD-mutated AML and could possibly serve as a biomarker to predict drug resistance.
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http://dx.doi.org/10.1002/1878-0261.12640DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7138400PMC
April 2020

Biodegradable Nanocarriers Resembling Extracellular Vesicles Deliver Genetic Material with the Highest Efficiency to Various Cell Types.

Small 2020 01 16;16(3):e1904880. Epub 2019 Dec 16.

Institute for Infection Prevention and Hospital Epidemiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106, Freiburg, Germany.

Efficient delivery of genetic material to primary cells remains challenging. Here, efficient transfer of genetic material is presented using synthetic biodegradable nanocarriers, resembling extracellular vesicles in their biomechanical properties. This is based on two main technological achievements: generation of soft biodegradable polyelectrolyte capsules in nanosize and efficient application of the nanocapsules for co-transfer of different RNAs to tumor cell lines and primary cells, including hematopoietic progenitor cells and primary T cells. Near to 100% efficiency is reached using only 2.5 × 10 pmol of siRNA, and 1 × 10 nmol of mRNA per cell, which is several magnitude orders below the amounts reported for any of methods published so far. The data show that biodegradable nanocapsules represent a universal and highly efficient biomimetic platform for the transfer of genetic material with the utmost potential to revolutionize gene transfer technology in vitro and in vivo.
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http://dx.doi.org/10.1002/smll.201904880DOI Listing
January 2020

Extracellular ATP and Purinergic P2Y Receptor Signaling Promote Liver Tumorigenesis in Mice by Exacerbating DNA Damage.

Cancer Res 2020 02 10;80(4):699-708. Epub 2019 Dec 10.

Department of Medicine II, Medical Center - University of Freiburg and Faculty of Medicine, University Hospital Freiburg, Freiburg, Germany.

Release of ATP to the extracellular compartment and subsequent activation of purinergic receptors is a conserved mechanism mediating inflammatory responses and cell fate decisions in various organs including the liver. Previous findings suggest that extracellular ATP may promote liver tumorigenesis, however, the underlying mechanisms are poorly understood. Therefore, our aim was to dissect the functions of extracellular ATP and P2Y receptors (P2YR) during hepatocarcinogenesis. Liver tumors were induced in wild-type and knockout mice by intraperitoneal diethylnitrosamine (DEN) injection. Tumorigenesis was analyzed after 8 to 10 months and molecular analyses were performed at different stages of tumorigenesis , as well as in primary mouse hepatocytes . Liver tumor incidence and tumor numbers were strongly reduced in mice, whereas tumor size and morphology were comparable to wild-type controls, suggesting that P2YR contributes to tumor initiation. Mechanistically, hepatocyte proliferation in DEN-treated mice was reduced, which correlated with reduced c-JUN and CCND1 but increased p21 expression. Moreover, DNA damage as determined by hepatocellular expression of γH2A.X and of genes related to genotoxic stress, as well as STAT3 phosphorylation, was reduced in the absence of . Administration of genotoxic agents to primary hepatocytes confirmed that DNA damage was indeed exacerbated by extracellular ATP, subsequent P2YR activation, and downstream intracellular calcium-dependent signal transduction. In conclusion, our data reveal that extracellular ATP and subsequent P2YR function stimulate DNA damage responses and hepatocyte proliferation, thereby promoting hepatocarcinogenesis. Targeting this pathway may be an attractive approach for chemoprevention of hepatocellular carcinoma. SIGNIFICANCE: Extracellular ATP and subsequent P2Y receptor function stimulate DNA damage responses and hepatocyte proliferation, thereby promoting hepatocarcinogenesis in mice. Targeting this pathway may be an attractive approach for chemoprevention of hepatocellular carcinoma. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/4/699/F1.large.jpg.
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http://dx.doi.org/10.1158/0008-5472.CAN-19-1909DOI Listing
February 2020

Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition).

Authors:
Andrea Cossarizza Hyun-Dong Chang Andreas Radbruch Andreas Acs Dieter Adam Sabine Adam-Klages William W Agace Nima Aghaeepour Mübeccel Akdis Matthieu Allez Larissa Nogueira Almeida Giorgia Alvisi Graham Anderson Immanuel Andrä Francesco Annunziato Achille Anselmo Petra Bacher Cosima T Baldari Sudipto Bari Vincenzo Barnaba Joana Barros-Martins Luca Battistini Wolfgang Bauer Sabine Baumgart Nicole Baumgarth Dirk Baumjohann Bianka Baying Mary Bebawy Burkhard Becher Wolfgang Beisker Vladimir Benes Rudi Beyaert Alfonso Blanco Dominic A Boardman Christian Bogdan Jessica G Borger Giovanna Borsellino Philip E Boulais Jolene A Bradford Dirk Brenner Ryan R Brinkman Anna E S Brooks Dirk H Busch Martin Büscher Timothy P Bushnell Federica Calzetti Garth Cameron Ilenia Cammarata Xuetao Cao Susanna L Cardell Stefano Casola Marco A Cassatella Andrea Cavani Antonio Celada Lucienne Chatenoud Pratip K Chattopadhyay Sue Chow Eleni Christakou Luka Čičin-Šain Mario Clerici Federico S Colombo Laura Cook Anne Cooke Andrea M Cooper Alexandra J Corbett Antonio Cosma Lorenzo Cosmi Pierre G Coulie Ana Cumano Ljiljana Cvetkovic Van Duc Dang Chantip Dang-Heine Martin S Davey Derek Davies Sara De Biasi Genny Del Zotto Gelo Victoriano Dela Cruz Michael Delacher Silvia Della Bella Paolo Dellabona Günnur Deniz Mark Dessing James P Di Santo Andreas Diefenbach Francesco Dieli Andreas Dolf Thomas Dörner Regine J Dress Diana Dudziak Michael Dustin Charles-Antoine Dutertre Friederike Ebner Sidonia B G Eckle Matthias Edinger Pascale Eede Götz R A Ehrhardt Marcus Eich Pablo Engel Britta Engelhardt Anna Erdei Charlotte Esser Bart Everts Maximilien Evrard Christine S Falk Todd A Fehniger Mar Felipo-Benavent Helen Ferry Markus Feuerer Andrew Filby Kata Filkor Simon Fillatreau Marie Follo Irmgard Förster John Foster Gemma A Foulds Britta Frehse Paul S Frenette Stefan Frischbutter Wolfgang Fritzsche David W Galbraith Anastasia Gangaev Natalio Garbi Brice Gaudilliere Ricardo T Gazzinelli Jens Geginat Wilhelm Gerner Nicholas A Gherardin Kamran Ghoreschi Lara Gibellini Florent Ginhoux Keisuke Goda Dale I Godfrey Christoph Goettlinger Jose M González-Navajas Carl S Goodyear Andrea Gori Jane L Grogan Daryl Grummitt Andreas Grützkau Claudia Haftmann Jonas Hahn Hamida Hammad Günter Hämmerling Leo Hansmann Goran Hansson Christopher M Harpur Susanne Hartmann Andrea Hauser Anja E Hauser David L Haviland David Hedley Daniela C Hernández Guadalupe Herrera Martin Herrmann Christoph Hess Thomas Höfer Petra Hoffmann Kristin Hogquist Tristan Holland Thomas Höllt Rikard Holmdahl Pleun Hombrink Jessica P Houston Bimba F Hoyer Bo Huang Fang-Ping Huang Johanna E Huber Jochen Huehn Michael Hundemer Christopher A Hunter William Y K Hwang Anna Iannone Florian Ingelfinger Sabine M Ivison Hans-Martin Jäck Peter K Jani Beatriz Jávega Stipan Jonjic Toralf Kaiser Tomas Kalina Thomas Kamradt Stefan H E Kaufmann Baerbel Keller Steven L C Ketelaars Ahad Khalilnezhad Srijit Khan Jan Kisielow Paul Klenerman Jasmin Knopf Hui-Fern Koay Katja Kobow Jay K Kolls Wan Ting Kong Manfred Kopf Thomas Korn Katharina Kriegsmann Hendy Kristyanto Thomas Kroneis Andreas Krueger Jenny Kühne Christian Kukat Désirée Kunkel Heike Kunze-Schumacher Tomohiro Kurosaki Christian Kurts Pia Kvistborg Immanuel Kwok Jonathan Landry Olivier Lantz Paola Lanuti Francesca LaRosa Agnès Lehuen Salomé LeibundGut-Landmann Michael D Leipold Leslie Y T Leung Megan K Levings Andreia C Lino Francesco Liotta Virginia Litwin Yanling Liu Hans-Gustaf Ljunggren Michael Lohoff Giovanna Lombardi Lilly Lopez Miguel López-Botet Amy E Lovett-Racke Erik Lubberts Herve Luche Burkhard Ludewig Enrico Lugli Sebastian Lunemann Holden T Maecker Laura Maggi Orla Maguire Florian Mair Kerstin H Mair Alberto Mantovani Rudolf A Manz Aaron J Marshall Alicia Martínez-Romero Glòria Martrus Ivana Marventano Wlodzimierz Maslinski Giuseppe Matarese Anna Vittoria Mattioli Christian Maueröder Alessio Mazzoni James McCluskey Mairi McGrath Helen M McGuire Iain B McInnes Henrik E Mei Fritz Melchers Susanne Melzer Dirk Mielenz Stephen D Miller Kingston H G Mills Hans Minderman Jenny Mjösberg Jonni Moore Barry Moran Lorenzo Moretta Tim R Mosmann Susann Müller Gabriele Multhoff Luis Enrique Muñoz Christian Münz Toshinori Nakayama Milena Nasi Katrin Neumann Lai Guan Ng Antonia Niedobitek Sussan Nourshargh Gabriel Núñez José-Enrique O'Connor Aaron Ochel Anna Oja Diana Ordonez Alberto Orfao Eva Orlowski-Oliver Wenjun Ouyang Annette Oxenius Raghavendra Palankar Isabel Panse Kovit Pattanapanyasat Malte Paulsen Dinko Pavlinic Livius Penter Pärt Peterson Christian Peth Jordi Petriz Federica Piancone Winfried F Pickl Silvia Piconese Marcello Pinti A Graham Pockley Malgorzata Justyna Podolska Zhiyong Poon Katharina Pracht Immo Prinz Carlo E M Pucillo Sally A Quataert Linda Quatrini Kylie M Quinn Helena Radbruch Tim R D J Radstake Susann Rahmig Hans-Peter Rahn Bartek Rajwa Gevitha Ravichandran Yotam Raz Jonathan A Rebhahn Diether Recktenwald Dorothea Reimer Caetano Reis e Sousa Ester B M Remmerswaal Lisa Richter Laura G Rico Andy Riddell Aja M Rieger J Paul Robinson Chiara Romagnani Anna Rubartelli Jürgen Ruland Armin Saalmüller Yvan Saeys Takashi Saito Shimon Sakaguchi Francisco Sala-de-Oyanguren Yvonne Samstag Sharon Sanderson Inga Sandrock Angela Santoni Ramon Bellmàs Sanz Marina Saresella Catherine Sautes-Fridman Birgit Sawitzki Linda Schadt Alexander Scheffold Hans U Scherer Matthias Schiemann Frank A Schildberg Esther Schimisky Andreas Schlitzer Josephine Schlosser Stephan Schmid Steffen Schmitt Kilian Schober Daniel Schraivogel Wolfgang Schuh Thomas Schüler Reiner Schulte Axel Ronald Schulz Sebastian R Schulz Cristiano Scottá Daniel Scott-Algara David P Sester T Vincent Shankey Bruno Silva-Santos Anna Katharina Simon Katarzyna M Sitnik Silvano Sozzani Daniel E Speiser Josef Spidlen Anders Stahlberg Alan M Stall Natalie Stanley Regina Stark Christina Stehle Tobit Steinmetz Hannes Stockinger Yousuke Takahama Kiyoshi Takeda Leonard Tan Attila Tárnok Gisa Tiegs Gergely Toldi Julia Tornack Elisabetta Traggiai Mohamed Trebak Timothy I M Tree Joe Trotter John Trowsdale Maria Tsoumakidou Henning Ulrich Sophia Urbanczyk Willem van de Veen Maries van den Broek Edwin van der Pol Sofie Van Gassen Gert Van Isterdael René A W van Lier Marc Veldhoen Salvador Vento-Asturias Paulo Vieira David Voehringer Hans-Dieter Volk Anouk von Borstel Konrad von Volkmann Ari Waisman Rachael V Walker Paul K Wallace Sa A Wang Xin M Wang Michael D Ward Kirsten A Ward-Hartstonge Klaus Warnatz Gary Warnes Sarah Warth Claudia Waskow James V Watson Carsten Watzl Leonie Wegener Thomas Weisenburger Annika Wiedemann Jürgen Wienands Anneke Wilharm Robert John Wilkinson Gerald Willimsky James B Wing Rieke Winkelmann Thomas H Winkler Oliver F Wirz Alicia Wong Peter Wurst Jennie H M Yang Juhao Yang Maria Yazdanbakhsh Liping Yu Alice Yue Hanlin Zhang Yi Zhao Susanne Maria Ziegler Christina Zielinski Jakob Zimmermann Arturo Zychlinsky

Eur J Immunol 2019 Oct;49(10):1457-1973

Max Planck Institute for Infection Biology, Berlin, Germany.

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.
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http://dx.doi.org/10.1002/eji.201970107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7350392PMC
October 2019

Astrogliosis Releases Pro-Oncogenic Chitinase 3-Like 1 Causing MAPK Signaling in Glioblastoma.

Cancers (Basel) 2019 Sep 26;11(10). Epub 2019 Sep 26.

Translational NeuroOncology Research Group, Medical Center, University of Freiburg, 79106 Freiburg, Germany.

Although reactive astrocytes constitute a major component of the cellular environment in glioblastoma, their function and crosstalk to other components of the environment is still poorly understood. Gene expression analysis of purified astrocytes from both the tumor core and non-infiltrated cortex reveals a tumor-related up-regulation of Chitinase 3-like 1 (CHI3L1), a cytokine which is related to inflammation, extracellular tissue remodeling, and fibrosis. Further, we established and validated a co-culture model to investigate the impact of reactive astrocytes within the tumor microenvironment. Here we show that reactive astrocytes promote a subtype-shift of glioblastoma towards the mesenchymal phenotype, driving mitogen-activated protein kinases (MAPK) signaling as well as increased proliferation and migration. In addition, we demonstrate that MAPK signaling is directly caused by a CHI3L1-IL13RA2 co-binding, which leads to increased downstream MAPK and AKT signaling. This novel microenvironmental crosstalk highlights the crucial role of non-neoplastic cells in malignant brain tumors and opens up new perspectives for targeted therapies in glioblastoma.
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http://dx.doi.org/10.3390/cancers11101437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6826948PMC
September 2019

Phosphorylation of BECLIN-1 by BCR-ABL suppresses autophagy in chronic myeloid leukemia.

Haematologica 2020 05 8;105(5):1285-1293. Epub 2019 Aug 8.

Department of Internal Medicine I, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany

Autophagy is a genetically regulated process of adaptation to metabolic stress and was recently shown to be involved in the treatment response of chronic myeloid leukemia (CML). However, data are limited and the molecular mechanism of autophagy regulators in the process of leukemogenesis is not completely understood. Here we show that knockdown, but not deletion in a murine CML model leads to a reduced leukemic burden and results in a significantly prolonged median survival of targeted mice. Further analyses of murine cell lines and primary patient material indicate that active BCR-ABL directly interacts with BECLIN-1 and phosphorylates its tyrosine residues 233 and 352, resulting in autophagy suppression. By using phosphorylation-deficient and phosphorylation-mimic mutants, we identify BCR-ABL induced BECLIN-1 phosphorylation as a crucial mechanism for BECLIN-1 complex formation: interaction analyses exhibit diminished binding of the positive autophagy regulators UVRAG, VPS15, ATG14 and VPS34 and enhanced binding of the negative regulator Rubicon to BCR-ABL-phosphorylated BECLIN-1. Taken together, our findings show interaction of BCR-ABL and BECLIN-1 thereby highlighting the importance of BECLIN-1-mediated autophagy in BCR-ABL cells.
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http://dx.doi.org/10.3324/haematol.2018.212027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7193473PMC
May 2020

Inactivation of oral biofilms using visible light and water-filtered infrared A radiation and indocyanine green.

Future Med Chem 2019 07 1;11(14):1721-1739. Epub 2019 Aug 1.

Department of Operative Dentistry & Periodontology, Center for Dental Medicine, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

To investigate the antimicrobial photodynamic therapy (aPDT) of visible light and water-filtered infrared A radiation in combination with indocyanine green (ICG) on planktonic oral microorganisms as well as on oral biofilm. The irradiation was conducted for 5 min in combination with ICG. Treatment with chlorhexidine served as a positive control. The number of colony forming units and bacterial vitality were quantified. All tested bacterial strains and salivary bacteria were killed at a level of 3log The colony forming units of the initial mature oral biofilms were strongly reduced. The high bactericidal effect of aPDT was confirmed by live/dead staining. The aPDT using visible light and water-filtered infrared A radiation and ICG has the potential to treat periodontitis and peri-implantitis.
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http://dx.doi.org/10.4155/fmc-2018-0522DOI Listing
July 2019

Phenotypical and functional analysis of donor lymphocyte infusion products after long-term cryopreservation.

Transfus Apher Sci 2020 Feb 10;59(1):102594. Epub 2019 Jul 10.

Department of Hematology, Oncology and Stem Cell Transplantation, University of Freiburg, Faculty of Medicine, Freiburg, Germany.

Donor lymphocyte infusions, collected from peripheral blood by apheresis, are regularly used to re-establishing disease control in patients with impending or full relapse after allogeneic cell transplantation. The cryopreservation and thawing processes of the cellular products, required for clinical needs, result in a decreased cellular recovery. The aim of this study was to perform an integral analysis of phenotypic and functional characteristics in different cell populations, within cryopreserved products used for therapeutic purposes. A total of 77 cryopreserved products were analysed. Cell viability and subpopulations such as CD3, CD4, CD8, CD14 and CD56 cells were quantified by FACS. Cell proliferation, cytotoxic capacity and CD4 intracellular ATP content were evaluated. A significant loss of cell viability was observed. CD56 cells were significantly reduced when compared with mononuclear cells without cryopreservation. Cell proliferation was also significantly reduced in the cryopreserved products. Cytotoxic capacity was decreased as well although it did not reach statistical significance. However, CD4 intracellular ATP was increased in the cryopreserved products. The analysed functional cell properties showed a wide distribution range although the apheresis, cryopreservation and thawing procedures were similar in all the analysed samples. Our findings may be useful for an improved characterisation of cryopreserved products to be used as donor lymphocyte infusion for therapeutic purposes.
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http://dx.doi.org/10.1016/j.transci.2019.06.022DOI Listing
February 2020

Human organotypic brain slice culture: a novel framework for environmental research in neuro-oncology.

Life Sci Alliance 2019 08 27;2(4). Epub 2019 Jun 27.

Translational NeuroOncology Research Group, Medical Center, University of Freiburg, Freiburg im Breisgau, Germany

When it comes to the human brain, models that closely mimic in vivo conditions are lacking. Living neuronal tissue is the closest representation of the in vivo human brain outside of a living person. Here, we present a method that can be used to maintain therapeutically resected healthy neuronal tissue for prolonged periods without any discernible changes in tissue vitality, evidenced by immunohistochemistry, genetic expression, and electrophysiology. This method was then used to assess glioblastoma (GBM) progression in its natural environment by microinjection of patient-derived tumor cells into cultured sections. The result closely resembles the pattern of de novo tumor growth and invasion, drug therapy response, and cytokine environment. Reactive transformation of astrocytes, as an example of the cellular nonmalignant tumor environment, can be accurately simulated with transcriptional differences similar to those of astrocytes isolated from acute GBM specimens. In a nutshell, we present a simple method to study GBM in its physiological environment, from which valuable insights can be gained. This technique can lead to further advancements in neuroscience, neuro-oncology, and pharmacotherapy.
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http://dx.doi.org/10.26508/lsa.201900305DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6599970PMC
August 2019

Streptococcus spp. and Fusobacterium nucleatum in tongue dorsum biofilm from halitosis patients: a fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) study.

New Microbiol 2019 Apr 29;42(2):108-113. Epub 2019 Apr 29.

Department of Life, Health and Environmental Sciences, University of L'Aquila, Via Vetoio, Coppito 2, 67100, L'Aquila, Italy.

The present study involved a qualitative and quantitative evaluation of tongue dorsum biofilms sampled from halitosis patients and healthy volunteers. The aim of the study was to quantify the distribution of Streptococcus spp. and Fusobacterium nucleatum within the oral halitosis biofilm in order to highlight the role of these bacterial members in halitosis. Tongue plaque samples from four halitosis-diagnosed patients and four healthy volunteers were analyzed and compared. The visualization and quantification of the tongue dorsum biofilm was performed combining fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM). Eubacteria, Streptococcus spp. and Fusobacterium nucleatum were stained using specific fluorescent probes. For a comparison of the two tested biofilm groups the Wilcoxon rank-sum test was used. Morphological analysis by CLSM illustrated the distribution of the species which were tracked. Streptococcus spp. appeared to be enclosed within the samples and always associated to F. nucleatum. Furthermore, compared to the control group the biofilm within the halitosis group contained significantly higher proportions of F. nucleatum and Streptococcus spp., as revealed by the FISH and CLSM-analysis. The total microbial load and relative proportions of F. nucleatum and Streptococcus spp. can be considered as causative factors of halitosis and thus, as potential treatment targets.
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April 2019

Tspan8 is expressed in breast cancer and regulates E-cadherin/catenin signalling and metastasis accompanied by increased circulating extracellular vesicles.

J Pathol 2019 08 18;248(4):421-437. Epub 2019 Jun 18.

Institute for Infection Prevention and Hospital Epidemiology; Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Tspan8 exhibits a functional role in many cancer types including pancreatic, colorectal, oesophagus carcinoma, and melanoma. We present a first study on the expression and function of Tspan8 in breast cancer. Tspan8 protein was present in the majority of human primary breast cancer lesions and metastases in the brain, bone, lung, and liver. In a syngeneic rat breast cancer model, Tspan8 tumours formed multiple liver and spleen metastases, while Tspan8 tumours exhibited a significantly diminished ability to metastasise, indicating a role of Tspan8 in metastases. Addressing the underlying molecular mechanisms, we discovered that Tspan8 can mediate up-regulation of E-cadherin and down-regulation of Twist, p120-catenin, and β-catenin target genes accompanied by the change of cell phenotype, resembling the mesenchymal-epithelial transition. Furthermore, Tspan8 cells exhibited enhanced cell-cell adhesion, diminished motility, and decreased sensitivity to irradiation. As a regulator of the content and function of extracellular vesicles (EVs), Tspan8 mediated a several-fold increase in EV number in cell culture and the circulation of tumour-bearing animals. We observed increased protein levels of E-cadherin and p120-catenin in these EVs; furthermore, Tspan8 and p120-catenin were co-immunoprecipitated, indicating that they may interact with each other. Altogether, our findings show the presence of Tspan8 in breast cancer primary lesion and metastases and indicate its role as a regulator of cell behaviour and EV release in breast cancer. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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http://dx.doi.org/10.1002/path.5281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771825PMC
August 2019

Circulating cKIT and PDGFRA DNA indicates disease activity in Gastrointestinal Stromal Tumor (GIST).

Int J Cancer 2019 10 29;145(8):2292-2303. Epub 2019 Apr 29.

Department of Hematology, Oncology and Stem Cell Transplantation, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

This prospective trial aimed to investigate whether tumor-specific cKIT and PDGFRA mutations can be detected and quantified in circulating tumor (ct)DNA in patients with active GIST, and whether detection indicates disease activity. We included 25 patients with active disease and cKIT or PDGFRA mutations detected in tissue. Mutant ctDNA was detected in the peripheral blood plasma using allele-specific ligation (L-)PCR and droplet digital (d)PCR. CtDNA harboring tumor-specific cKIT or PDGFRA mutations was detected at least once in 16 out of 25 patients using L-PCR (64%) and in 20 out of 25 patients with dPCR (80%). Using dPCR, the absolute numbers of ctDNA fragments (DNA copies/ml) and the mutant allele frequency (MAF; in percent of wild-type control) strongly correlated with tumor size expressed as RECIST1.1 sum of diameter (SOD) in mm (ρ = 0.3719 and 0.408, respectively, p < 0.0001) and response status (ρ = 0.3939 and 0.392, respectively, p < 0.0001 and p < 0.001). Specificity of dPCR for detection of progression was 79.2% with a sensitivity of 55.2% and dPCR discriminated CR from active disease with a specificity of 96% and s sensitivity of 44.7%. With L-PCR, correlations of MAF with tumor size and response status were less prominent. Serial ctDNA measurement reflected individual disease courses over time. Targeted panel sequencing of four patients detected additional driver mutations in all cases and secondary resistance mutations in two cases. Thus, ctDNA indicates disease activity in patients with GIST and should be incorporated as companion biomarker in future prospective trials.
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http://dx.doi.org/10.1002/ijc.32282DOI Listing
October 2019

Genotyping of circulating cell-free DNA enables noninvasive tumor detection in myxoid liposarcomas.

Int J Cancer 2019 08 9;145(4):1148-1161. Epub 2019 Mar 9.

Department of Plastic and Hand Surgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Soft tissue sarcomas (STS) are rare tumors of mesenchymal origin. About 50% of patients with STS experience relapse and more than 30% will die within 10 years after diagnosis. In this study we investigated circulating free DNA (cfDNA) and tumor-specific genetic alterations therein (circulating tumor DNA, ctDNA) as diagnostic biomarkers. Plasma concentrations and fragmentation of cfDNA was analyzed with quantitative PCR. Patients with STS (n = 64) had significantly higher plasma concentrations and increased fragmentation of cfDNA when compared to patients in complete remission (n = 19) and healthy controls (n = 41) (p < 0.01 and p < 0.001). Due to overlapping values between patients with STS and controls, the sensitivity and specificity of these assays is limited. Sensitive assays to detect genomic alterations in cfDNA of synovial sarcomas (t(X;18)), myxoid liposarcomas (t(12;16) and TERT C228T promoter mutation) and well-differentiated/de-differentiated liposarcomas (MDM2 amplifications) were established. ctDNA was quantified in nine liposarcoma patients during the course of their treatment. Levels of breakpoint t(12;16) and TERT C228T ctDNA correlated with the clinical course and tumor burden in patients with myxoid liposarcomas (n = 4). ctDNA could detect minimal residual disease and tumor recurrence. In contrast, detection of MDM2 amplifications was not sensitive enough to detect tumors in patients with well-differentiated/de-differentiated liposarcomas (n = 5). Genotyping of cfDNA for tumor specific genetic alterations is a feasible and promising approach for monitoring tumor activity in patients with myxoid liposarcomas. Detection of ctDNA during follow-up examinations despite negative standard imaging studies might warrant more sensitive imaging (e.g. PET-CT) or closer follow-up intervals to timely localize and treat recurrences.
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http://dx.doi.org/10.1002/ijc.32216DOI Listing
August 2019

The transcription factor c-Jun/AP-1 promotes liver fibrosis during non-alcoholic steatohepatitis by regulating Osteopontin expression.

Cell Death Differ 2019 09 18;26(9):1688-1699. Epub 2019 Feb 18.

Department of Medicine II, Medical Center-University of Freiburg and Faculty of Medicine, University Hospital Freiburg, Freiburg, Germany.

Progression of non-alcoholic fatty liver disease (NAFLD) from steatosis to non-alcoholic steatohepatitis (NASH) is a key step of NASH pathogenesis. The AP-1 transcription factor c-Jun is an important regulator of hepatic stress responses, but its contribution to NASH pathogenesis remains poorly defined. We therefore addressed c-Jun expression in liver biopsies of patients with steatosis and NASH. The role of c-Jun during NASH pathogenesis was analyzed mechanistically in c-Jun mutant mice fed with a methionine- and choline-deficient diet (MCDD). Disease progression from steatosis to NASH in patients correlated with increased c-Jun expression in hepatocytes, while its expression in non-parenchymal liver cells (NPLCs) particularly correlated with fibrosis. Analysis of untreated and MCDD-fed mice lacking c-Jun in hepatocytes (c-Jun) revealed that c-Jun promotes hepatocyte survival, thereby protecting against the regenerative ductular reaction (DR) of Sox9/Osteopontin (Opn) co-expressing NPLCs, expression of the Opn receptor CD44 and fibrosis, which were all exacerbated in c-Jun mice. Since Opn and c-Jun were co-expressed by NPLCs in mice and patients with NASH, we wondered whether the increased fibrosis observed in c-Jun mice could be rescued by additional c-Jun deletion in NPLCs (c-Jun). c-Jun mice with NASH indeed exhibited reduced expression of Opn and CD44 in NPLCs, impaired DR and reduced fibrosis. A similar phenotype was observed in Opn knockout mice, suggesting that the observed functions of c-Jun were indeed Opn-dependent. In conclusion, c-Jun expression correlates with disease progression from steatosis to NASH in patients and exerts cell-type-specific functions in mice: In hepatocytes, it promotes cell survival thereby limiting the DR and fibrogenesis. In NPLCs, it rather promotes the DR and fibrogenesis by regulating expression of Opn and CD44.
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http://dx.doi.org/10.1038/s41418-018-0239-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6748141PMC
September 2019

MMP14 empowers tumor-initiating breast cancer cells under hypoxic nutrient-depleted conditions.

FASEB J 2019 03 6;33(3):4124-4140. Epub 2018 Dec 6.

Institute of Molecular Medicine and Cell Research, Medical Faculty, University of Freiburg, Freiburg, Germany.

Tumor-initiating cells (TICs) existing in breast cancer are thought to be involved in initiation, progression, and relapse of tumors. In these processes, the epithelial-to-mesenchymal transition (EMT) and proteases are crucial factors that also dependent on the tumor milieu, including hypoxic nutrient-deprived, as well as normoxic nutrient-rich, environments. Therefore, we investigated EMT and proteases in TICs and their response to different environments by means of a newly generated immortalized TIC (iTIC) line. With the use of primary CD24CD90CD45 TICs from the mouse mammary tumor virus-polyoma middle T mouse breast cancer model, iTICs were generated by single cell-initiated sphere and subsequent 2-dimensional monolayer culture. Our data demonstrate the possibility to generate iTICs that are highly tumorigenic in culture and in mouse mammary fat pad. Contrasting environmental conditions provide these cells with a phenotypic and molecular plasticity that has a growth-promoting character in nutrient-rich normoxia and a motile character in nutrient-deprived hypoxia. Expression profiling revealed partial and dynamically changing EMT states, as well as a significantly up-regulated proteolytic signature, including many metalloproteinases, such as matrix metalloproteinase 14 ( Mmp14). Inhibitor treatment of metalloproteinases, as well as short hairpin RNA-mediated knockdown of Mmp14 strongly impacted TIC characteristics, including tumor initiation, cell growth, migration, and invasion, especially in starved environments. We conclude that metalloproteinases empower TICs to adapt to changing environments.-Hillebrand, L. E., Wickberg, S. M., Gomez-Auli, A., Follo, M., Maurer, J., Busch, H., Boerries, M., Reinheckel, T. MMP14 empowers tumor-initiating breast cancer cells under hypoxic nutrient-depleted conditions.
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http://dx.doi.org/10.1096/fj.201801127RDOI Listing
March 2019