Atanasova, V. S. | Search bioRxiv

bioRxiv2024

Aggressive KRAS mutations direct TGF-β response towards partial EMT in patient-derived colorectal cancer tumoroids

Transforming growth factor beta (TGF-{beta}) exhibits complex and context-dependent cellular responses. While it mostly induces tumor-suppressive effects in early stages of tumorigenesis, its tumor promoting properties are evident in advanced disease. This TGF-{beta} duality is still not fully understood, and whether TGF-{beta} supports invasion and metastasis by influencing cancer cells directly, or rather through the stromal tumor compartment remains a matter of debate. Here, we utilized a library of colorectal cancer (CRC) patient-derived tumoroids (PDTs), representing a spectrum of tumor stages, to study cancer cell-specific responses to TGF-{beta}. Using medium conditions allowing for the differentiation of PDTs, we observed TGF-{beta} induced tumor-suppressive effects in early-stage tumoroids. PDTs with TGF-{beta} pathway mutations or PDTs derived from metastatic tumors were insensitive to the treatment. Notably, one tumoroid line harboring an atypical KRASQ22K mutation underwent partial epithelial-to-mesenchymal transition (EMT), associated with morphological changes and increased invasiveness. On a molecular level, this was accompanied by elevated expression of mesenchymal genes, as well as deregulation of pathways associated with matrix remodeling and cell adhesion. Our results suggest that tumor cell intrinsic responses to TGF-{beta} are critical in determining its tumor-suppressive or -promoting effects.

cancer biology↗

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↗