Abstract 1275: Advancing cancer research with PDX-derived organoids: Insights into cancer stem cells and metastasis

Abstract Patient-derived xenograft (PDX) organoids (PDXOs) are emerging as powerful tools for studying cancer biology and advancing therapeutic discovery. In this study, we report the generation of PDX-derived organoids from pancreatic ductal adenocarcinoma (PDAC) and colorectal cancer (CRC) PDX models, establishing a translational framework for personalized cancer research. A key focus was the detection and enrichment of cancer stem cells (CSCs) within colorectal cancer PDXOs (CR PDXOs). Through optimized culture conditions, we achieved a remarkable 30-fold enrichment of CSCs, a pivotal population driving tumor progression, therapeutic resistance, and metastasis. This enrichment highlights the utility of PDXOs in dissecting stem cell biology and targeting CSC-associated mechanisms. Using the PDAC model, we implemented tricistronic transduction to generate stable PDXOs expressing NanoLuc, mCherry, and EGFP fluorescent proteins. This genetic engineering strategy enables real-time monitoring of organoid dynamics and facilitates downstream applications, including in vivo studies. The reimplantation of these labeled PDXOs into immunocompromised mice successfully reestablished PDX tumors, demonstrating growth curves features nearly identical to those of the original PDX tumors. This PDXO-to-PDX approach underscores the fidelity of PDXOs in recapitulating patient-derived tumor biology. Further, we investigated metastatic potential using full single-cell dissociation and marker-based detection. Analysis of various tissues from mice bearing reimplanted PDAC PDXOs revealed the presence of metastatic cells in the liver, indicating the ability of PDXOs to model metastatic dissemination. This capability provides a unique platform to study metastatic mechanisms and evaluate anti-metastatic therapies. In conclusion, our study highlights the versatility and translational relevance of PDXOs in cancer research. By generating PDXOs from diverse models, enriching CSC populations, and employing advanced genetic tools for functional studies, we demonstrate the utility of PDXOs in capturing tumor complexity. The reimplantation experiments and detection of metastasis further validate PDXOs as robust systems bridging in vitro and in vivo research. This integrated approach offers critical insights into tumor biology, therapeutic responses, and metastatic behavior, paving the way for improved drug discovery and personalized treatment strategies. Citation Format: Nicolas Ancellin, Olivier Duchamp, Didier Grillot, Kenny Herry, Nicolas Legrand, Caroline Mignard. Advancing cancer research with PDX-derived organoids: Insights into cancer stem cells and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1275.