Abstract 5191: Modeling the metastatic tumor microenvironment: A co-culture platform for cancer and vascular organoids in drug screening

Abstract Patient-derived organoids (PDOs) have emerged as a promising tool for drug screening, as they can closely mimic the genetic profile and heterogeneity of real tumor tissues. Despite these advantages, PDOs cultured in isolation fall short in replicating the complex in vivo tumor environment, particularly the critical interactions with the vascular network. Research that neglects these tumor-vascular interactions provides only partial insights into drug responses and the metastatic potential of cancer cells. To address these limitations, we developed a co-culture system of cancer and vascular organoids to better simulate the authentic tumor microenvironment (TME). After four days of vascularized tumor organoid (vTO) culture, RFP-positive lung cancer organoids (LCO) were centrally positioned, encircled by blood vessels, creating an interconnected structure between the LCO and blood vessel organoids (BVO). As the culture period progressed, the LCO began to spread along the vascular network, and by day 10, RFP-positive LCO cells were observed in the peripheral BVO regions. To investigate strategies for limiting metastasis, we targeted the TGF-β pathway, known to play a key role in metastatic progression, within this novel metastatic platform. On day 5, we administered the TGF-β/Smad inhibitor A83-01. Image-based analysis revealed a reduction in LCO dissemination, while quantitative PCR analysis showed a dose-dependent decrease in the expression of genes associated with epithelial-to-mesenchymal transition (EMT) following A83-01 treatment. Additionally, to assess anti-cancer drug responses, we treated the vTO with the AXL inhibitor Bemcentinib. Image analysis indicated that the vTO exhibited higher drug resistance compared to LCO alone, and qPCR analysis confirmed a reduction in metastasis-associated gene expression. Taken together, this innovative co-culture platform, which incorporates metastatic cancer organoids, offers a structurally advanced model that more closely resembles the in vivo TME than previous drug screening methods. Therefore, this platform serves as a powerful new tool for studying metastatic cancer and provides a novel approach to evaluating metastasis-inhibiting drugs, new therapeutics targeting metastatic tumors, and combination therapies. Citation Format: Mingyun Lee, Yeojoon Yoon, Yong Soo Lee, Jinguen Rheey. Modeling the metastatic tumor microenvironment: A co-culture platform for cancer and vascular organoids in drug screening [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 5191.