Dolznig, H. | Search bioRxiv

bioRxiv2026

A cell death screen identifies macrophage-depleting agents with therapeutic potential

Macrophages are critical regulators of inflammation and tissue homeostasis, yet aberrant macrophage activation contributes to a wide spectrum of inflammatory and malignant diseases. Therapeutic strategies that directly reduce macrophage numbers have shown promise, but macrophage survival pathways remain incompletely defined, limiting the development of targeted therapeutic strategies. Here, we establish a high-throughput screening platform to identify small molecule inhibitors that impair macrophage survival. Screening a library of more than 2,000 targeted compounds in a cell survival assay, combined with in silico and in vitro analysis of macrophage specificity, revealed the identification of three potent inhibitors: BIX-01294, GSK-J4, and Masitinib. All three compounds downregulated leukemia inhibitory factor receptor (LIFR), whose inhibition markedly reduced macrophage viability. In vivo, these inhibitors effectively depleted large peritoneal macrophages, ameliorated key symptoms of macrophage activation syndrome (MAS), and suppressed tumor growth in a syngeneic transplanted melanoma model as well as in an autochthonous lung cancer model. Together, these findings identify small molecule-mediated macrophage depletion as a promising therapeutic strategy and establish an experimental approach to uncover regulators of macrophage survival.

immunology↗

bioRxiv2022

Mimicking tumor cell heterogeneity of colorectal cancer in a patient-derived organoid-fibroblast model

Patient-derived organoid (PDO) cancer models are generated from epithelial tumor cells. Although they reflect the molecular tumor characteristics, they lack the complexity of the tumor microenvironment, which is a key driver of tumorigenesis and therapy response. Here, we present a colorectal cancer (CRC) organoid model that incorporates epithelial cells and stromal fibroblasts from the same patient. Molecular characterization of primary cancer associated fibroblasts (CAFs) and matched normal fibroblasts (NF) revealed proteomic, secretome and gene expression differences in pathways associated with tumor related fibroblast function. Further, CAFs retained higher motility compared to NFs in vitro. Importantly, both CAFs and NFs supported cancer cell proliferation in 3D co-cultures, without the addition of classical niche factors. PDOs grown together with fibroblasts displayed a larger cellular heterogeneity of tumor cells compared to mono-cultures, and closely resembled the in vivo tumor morphology. This was also confirmed by the calculation of cellular proportions of epithelial cell subtypes in organoid mono-versus co-cultures, which were inferred through bioinformatics deconvolution of bulk RNA sequencing data using published single cell RNA sequencing datasets from CRC tissues. Additionally, we observed a mutual crosstalk between tumor cells and fibroblasts in the co-cultures. This was manifested by majorly deregulated pathways such as cell-cell communication and extracellular matrix remodeling in the organoids. For the fibroblasts, we observed enhanced expression of tumor induced marker genes and cytokines characteristic for myo- and immunogenic fibroblasts. This model will be vital as a physiological personalized tumor model to study disease mechanisms and therapy response in CRC. One Sentence SummaryPatient matched fibroblasts support tumor organoid growth in 3D co-culture and maintain intratumoral cellular heterogeneity and histo-morphology.

cancer biology↗