Biology subjects

Bornhaeuser, M.

Publications and source records attributed to Bornhaeuser, M..

7 recordsLinked to original sources

bioRxiv2026

Impact of chemotherapy on leukocyte stiffness -A longitudinal RT-DC study in a breast cancer patient

BackgroundThe physical properties of leukocytes, such as cell size and stiffness, are critical for their circulation in microcapillary networks where rapid shape changes are required to squeeze through vascular constrictions. Alterations in the cells physical phenotype can promote venous thromboembolism (VTE), a common cause of death in cancer patients receiving chemotherapy. While biochemical VTE predictors are well studied, physical properties of blood cells receive less attention. MethodsUsing real-time deformability cytometry (RT-DC), we monitored for the first time the physical phenotype of leukocytes in a longitudinal study of a breast cancer patient treated with epirubicin/cyclophosphamide (EC) and paclitaxel (Pax). ResultsThe leukocyte counts extracted from RT-DC were in good agreement with standard clinical leukograms and EC had no immediate effect on leukocyte properties. However, Pax caused a significant softening of granulo/monocytes and a stiffening of lymphocytes immediately after administration. Leukocyte size was constant throughout the therapy, but we observed an overall increase in leukocyte stiffness, which was restored to normal values 45 weeks post treatment. ConclusionTaken together, our data reveal chemotherapy-induced specific alterations of leukocyte stiffness potentially critical for microcirculation. Thus, RT-DC measurements can add important, yet currently not available information to VTE prediction in cancer patients.

biophysics↗

bioRxiv2026

Next-generation all-in-one CRISPR/Cas9 multiply-edited CD30CAR-T cells:Potency despite risk of translocations

BackgroundChimeric antigen receptor (CAR)-T cells are therapeutic breakthroughs against advanced non-Hodgkin lymphomas and myelomas. On the other hand, no CAR-T cell product has been so far clinically approved for therapy of Hodgkin Lymphoma (HL), T cell lymphoma (TCL), or Epstein-Barr-Virus (EBV)-associated lymphoproliferative diseases (EBV-LPDs). CD30 (TNFRSF8) is commonly expressed on HL and on subsets of TCL and EBV-LPDs. CD30CAR-T cells generated via transduction with viral vectors have been tested in clinical trials, showing overall good responses against HL. CAR-T cells produced entirely with locus-specific gene editing methods are emerging as attractive next-generation engineered cell products for ease of multiple seamless cell modifications. MethodsUsing CRISPR/Cas9-mediated techniques, we optimized homology-directed repair templates (HDRTs) and performed all-in-one multiplex editing to knock-in (KI) CD30CAR within the TCR constant (TRAC) locus and to simultaneously knock-out (KO) PD-1 or/and {beta}2M. CD30CAR-T cells were tested in CD30+ cell models of HL, TCL, and EBV-LPDs. ResultsWe compared mouse versus human anti-CD30 scFv designs in HDRTs incorporating TRAC homology arms, FcIg spacer/detection domain, and CD28 / CD3{zeta} signaling domains. We obtained an average of 30% TRACKICD30CAR-T cells and efficient in vitro cytotoxicity with CD30+ cell targets. CARs incorporating the high-affinity humanized 5F11 scFv showed the highest CAR expression, and the editing templates were further modified to incorporate a truncated CD34 (tCD34) spacer/detection domain. 5F11-CD30CAR-tCD34-T cells showed high CAR-KI rates (approx. 50-80% 12-14 days after editing) and potency in vitro and in vivo. Subsequently, we tested all-in-one CAR KI with additional KOs by co-electroporation of guide RNAs (gRNAs) targeting the genes encoding PD-1 or /and {beta}2M to improve function and allow for improved cell persistence in allogeneic recipients, respectively. Compared with CD30CAR-T cells, CD30CAR-{beta}2MKO-T cells were similarly viable and functional and showed low risk of translocations. PD1KO enabled CD30CAR-T cells to produce higher levels of cytotoxic features upon exposure to targets. However, simultaneous {beta}2MKO and PD-1KO compromised the expansion capacity of CD30CAR-T cells and resulted in detectable translocations. ConclusionsNon-virally engineered 5F11-CD30CAR-T cells represent a novel cell therapy modality against CD30+ lymphomas. Multiplex editing remains to be optimized to avoid unwanted genomic alterations and chromosomal translocations.

cancer biology↗

bioRxiv2025

Preclinical Efficacy of Tasquinimod in Myelodysplastic Neoplasms: Restoring Erythropoiesis and Mitigating Bone Loss

Myelodysplastic neoplasms (MDS) are clonal disorders characterized by ineffective hematopoiesis, dysplasia, and a risk of transformation into acute myeloid leukemia. MDS is also associated with a higher incidence of osteoporosis, suggesting a complex interplay between hematopoiesis, the bone marrow (BM) microenvironment, and bone homeostasis. Targeting inflammation has emerged as a promising therapeutic strategy, particularly in lower-risk MDS. Tasquinimod (TASQ) is a small-molecule inhibitor of the inflammatory alarmin S100A9, blocking its interaction with TLR4 and RAGE receptors. We investigated the efficacy of TASQ in modulating inflammation and improving disease phenotype using in vitro and in vivo MDS models. Immunofluorescence staining of human BM identified neutrophils and macrophages as primary S100A9 sources. Exposure of mesenchymal stromal cells (MSCs) to S100A9 induced TLR4 downstream signaling, resulting in increased expression of IRAK1, NF-{kappa}B-p65, IL-1{beta}, IL-18, caspase 1 and PD-L1. These effects were effectively abolished by TASQ. Additionally, TASQ restored the disturbed MSC-mediated hematopoietic support, as demonstrated by increased numbers of cobblestone area-forming cells and colony-forming units. In NHD13 MDS mice, TASQ (30 mg/kg, 12 weeks) improved hemoglobin and red blood cell counts, but exerted no effect in wild-type (WT) mice. Additionally, TASQ improved bone microarchitecture by increasing trabecular number and bone volume, likely a result of reduced osteoclast activity. Our findings suggest that TASQ mitigates inflammasome activation in the MDS BM, improving erythropoiesis and bone health. These results provide a necessary preclinical basis for clinical trials in lower-risk MDS patients, in whom anemia and osteoporosis often coexist.

cell biology↗

bioRxiv2024

Unbiased functional genetic screens reveal essential RNA modifications in human cancer and drug resistance

RNA modification pathways are mis-regulated in multiple types of human cancer. To comprehensively identify cancer-relevant RNA modifications and their regulators, we screened all 150 annotated human RNA modifying proteins across 18 different normal and cancer cell lines using a CRISPR-based genetic knockout system. Fifty RNA modifying proteins were essential for survival of at least one cell type. A third of these essential genes were amplified in 38 different human primary cancer types and potentially drive cancer growth. Unexpectedly, the number of essential genes per cell line varied considerably, and this variation was not due to tissue of origin. Instead, we found that cancer cell-specific mitochondrial metabolic plasticity was responsible for the unique requirement of certain RNA modifications. For example, leukemia cells with high intrinsic drug tolerance required mitochondrial flexibility to survive treatment with the anti-leukemic drugs cytarabine and venetoclax. Synthetic lethality screens revealed that drug-resistance is abolished by deleting the mitochondrial methyltransferase TRMT5, which is responsible for the formation of N1-methylguanosine (m1G) in the tRNA anticodon loop. In summary, our study identifies cancer-relevant RNA modifying enzymes, and reveals a novel promising drug target for therapy-resistant acute myeloid leukemia.

cell biology↗

bioRxiv2023

The histone modifier KAT2A presents a selective target in a subset of well-differentiated microsatellite-stable colorectal cancers

BackgroundLysine acetyltransferase 2A (KAT2A) plays a pivotal role in epigenetic gene regulation across various types of cancer. In colorectal cancer (CRC), upregulation of KAT2A is associated with a more aggressive phenotype. Our study aims to elucidate the molecular underpinnings of KAT2A dependency in CRC and assess the consequences of KAT2A depletion. MethodsWe conducted a comprehensive analysis by integrating CRISPR-Cas9 screening data with genomics, transcriptomics, and global acetylation patterns in CRC cell lines to pinpoint molecular markers indicative of KAT2A dependency. Additionally, we characterized the phenotypic effect of a CRISPR-Cas9-mediated KAT2A knockout and chemical inhibition of KAT2A in CRC cell lines and patient- derived 3D spheroid cultures. ResultsOur findings reveal that KAT2A dependency is closely associated with a lower mutational burden and increased differentiation grade in CRC cell lines, independent of the KAT2A expression levels. KAT2A dependent CRC cell lines display enriched H3K27ac marks at gene loci linked to enterocytic differentiation. Loss of KAT2A leads to decreased cell growth and viability, downregulation of proliferation- and stem cell-associated genes, and induction of differentiation markers. ConclusionA specific subset of CRCs with a more differentiated phenotype relies on KAT2A. For these CRC cases, KAT2A might represent a promising novel therapeutic target.

cancer biology↗

bioRxiv2023

CD38 promotes hematopoietic stem cell dormancy via c-Fos

A subpopulation of deeply quiescent, so-called dormant hematopoietic stem cells (dHSCs) resides at the top of the hematopoietic hierarchy and serves as a reserve pool for HSCs possessing the greatest long-term blood repopulation capacity. The state of dormancy protects the HSC pool from exhaustion throughout life, however excessive dormancy may block an efficient response to hematological stresses. The mechanisms of HSC dormancy remain elusive, mainly due to the absence of surface markers that allow dHSC prompt isolation. Here, we identify CD38 as a novel surface marker for murine dHSCs that is broadly applicable. Moreover, we demonstrate that cyclic adenosine diphosphate ribose (cADPR), the product of CD38 cyclase activity, regulates the expression of the transcription factor c-Fos by increasing cytoplasmic Ca2+ concentration. Strikingly, we uncover that c-Fos drives HSCs dormancy through the induction of the cell cycle inhibitor p57Kip2. Moreover, we found that CD38 ecto-enzymatic activity at the neighboring CD38-positive cells can promote human HSC quiescence. Together, CD38/cADPR/Ca2+/cFos/p57Kip2 axis maintains HSC dormancy. Pharmacological manipulations of this pathway can provide new strategies to expand dHSCs for transplantation or to activate them during hematological stresses.

cell biology↗

bioRxiv2017

Continuous high-resolution in vivo imaging reveals tumor-specific dissemination in an embryonic zebrafish xenograft model

Mechanisms mediating tumor metastasis are crucial for diagnostic and therapeutic targeting. Here, we take advantage of a transparent embryonic zebrafish xenograft model (eZXM) to visualize and track injected human leukemic and breast cancer cells in real time using selective plane illumination microscopy (SPIM) for up to 30 hours. Injected cells exhibited disease-specific patterns of intravascular distribution with leukemic cells moving faster than breast cancer cells. While breast cancer cells predominantly adhered to nearby regions, about 30% invaded the avascularized tissue, reminiscent of their metastatic phenotype. Survival of the injected tumor cells was partly inhibited by the cellular innate immune system of the recipient embryos and leukemic cell dissemination was effectively inhibited by pharmacological ROCK1 blockade. These observations, and the ability to image several embryos simultaneously, support the use of eZXM and SPIM imaging as a functional screening platform to identify compounds that restricts cancer cell spread and invasion.

cancer biology↗