Speaker
Description
"Background and Aims: Cholangiocarcinoma (CCA) is a highly aggressive tumor which arises from the biliary duct epithelium. Currently available models fail to recapitulate the full complexity of CCA, particularly the desmoplastic environment and the interplay between cancer cells and the extracellular matrix (ECM). We aimed to create an improved 3D in vitro model by combining patient-derived CCA organoids (CCAOs) with native CCA tumor and liver ECM, obtained by decellularization, to study the role of tumor cells in desmoplasia and ECM remodelling.
Method: Patient-derived CCA matrix (CCA-M) and tumor-free liver matrix (TFL-M) were obtained by decellularization of tumor and tumor-free liver biopsies from CCA patients. The decellularized scaffolds were biochemically and mechanically assessed using nanoindentation and rheology. Subsequently, CCA-M and TFL-M were recellularized with CCAOs. Tumor cell behavior of CCAOs in CCA-M, TFL-M was studied on a transcriptome level with bulk RNA-sequencing, and protein level with immunocytochemical stainings and Stable Isotope Labeling by Amino acids in Cell culture (SILAC)-based mass spectrometry. Cell viability measurements were taken for quantifying CCAO response to chemotherapeutics. Standard culture conditions of CCAOs in basement membrane extract (BME) were used as control.
Results: Decellularization of CCA tumor and liver tissue resulted in effective removal of cells while preserving ECM structure and retaining important characteristics of the tissue origin, including stiffness, collagen content, and the presence of desmoplasia, typically associated with CCA, in the tumor ECM. When culturing CCAOs in CCA-M, the expression profile of differentially expressed genes much more resembled the transcriptome of primary CCA tumor tissue in vivo compared to TFL-M (correlation coefficient (CC) CCA-M 0.83±0.03 vs CC TFL-M 0.70±0.03, p = 0.004) and BME (CC CCA-M 0.88±0.04 vs CC BME 0.63±0.06, p < 0.0001). This was accompanied by a significant difference in cell viability in response to exposure to gemcitabine, which is the standard of care treatment for CCA patients (mean viability at 100uM CCA-M 0.86 vs TFL-M 0.64, p = 0.018). These results provide evidence that the desmoplastic extracellular environment in CCA plays an important role in chemoresistance. Moreover, CCA-M induced specific extracellular matrix protein production in CCAOs, such as fibronectin 1 (FN1), which is related to desmoplasia and decreased patient survival. In TFL-M, lacking desmoplasia, CCAOs initiated a desmoplastic reaction directly through increased production of multiple collagen types (e.g. COL1A1, COL1A2, COL6A1, COL6A3).
Conclusion: This study demonstrates that combining tumor organoids and decellularized matrix provides a complex in vitro tumor model that can recapitulate key components of CCA biology, including transcriptome profiles, drug responses, and ECM remodeling activity. The increased production of ECM proteins, primarily collagens, indicates that epithelial tumor cells are able to contribute to their own desmoplastic environment. Complementing organoid-based culture models with tumor decellularized matrix is applicable to a variety of tumors and could result in overall better recapitulation of tumor behavior in vivo."
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