Abstract LB163: A microfluidic platform for developing circulating tumor cells (CTCs) organoids for precision medicine in pancreatic cancer

Abstract Introduction Pancreatic ductal adenocarcinoma (PDAC) is predicted to be the second leading cause of cancer death in the US by 2030. Besides the late detection and lack of effective treatments, the greatest treatment hurdle to PDAC is the ineffectiveness of patient-derived tumor models. Precision medicine-based treatment decisions require the generation of consistent and trackable complex organoid models that is not achievable by tissue biopsies. Liquid biopsies such as blood, instead, contain circulating biomarkers released by the tumor, among which especially interested in for this study are circulating tumor cells (CTCs). This work develops microfluidic 3D organoids from CTCs to be used as a precision medicine tool to predict and guide the drug response of early stage I-IIB (PDAC) patients. Experimental Methods CTCs are isolated from PDAC patient blood samples using microfluidic Labyrinth following removal of red blood cells with 6% dextran. Collected cells post-isolation are immunofluorescence (IF) stained with DAPI (nuclei), CD45 (leukocyte), pancytokeratin (type I/II cytokeratin 1-8, 10, 14- 16 and 19), Vimentin, and Epithelial cell adhesion molecule (EpCAM) to identify CTCs and characterize their phenotypes. The mold of the microfluidic platform for CTC organoids is fabricated with the standard SU-8 photolithography. The PDMS-based device is tested with a low seeding number of a pancreatic cancer CTC cell line labeled fluorescently. Decellularization of cancer associated fibroblasts (CAFs) generates the in vitro matrix that supplies amino-acid precursors for PDAC metabolism, promoting CTC organoid formation. Serial images of cell growth are obtained throughout the course using a Ti-20 microscope. After each 7-day culture, organoids are dissociated from the device and IF stained using a similar panel as above (with Ki67 marker instead of CD45 for cell proliferation). Preliminary gemcitabine dosage-performance analysis is performed on-chip. Results CTC count from the tested patient panel (n=16) averages 17.0±8.4/mL of blood. CAFs are successfully decellularized on-chip and the embedded pancreatic CTC cell line growth curve is generated. IF staining of the dissociated cells from the organoids confirms the proliferation of the loaded pseudo-CTCs. Conclusion The work above demonstrates the successful isolation of CTCs from PDAC patient blood samples and an engineered microfluidic platform to expand low abundance of cells into organoids. It has a potential to be tested and employed to expand CTCs from PDAC into organoids for drug screening. Citation Format: Yu Zhang, Scott Smith, Minal Nenwani, Valerie Gunchick, Vaibhav Sahai, Sunitha Nagrath, Deepak Nagrath. A microfluidic platform for developing circulating tumor cells (CTCs) organoids for precision medicine in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB163.