DanioCTC: Analysis of Circulating Tumor Cells from Metastatic Breast Cancer Patients in Zebrafish Xenografts

SIMPLE SUMMARY: DanioCTC is an approach that tackles a significant hurdle in cancer research: the scarcity of circulating tumor cells (CTCs) in animal models. These CTCs are crucial in understanding how cancer spreads, especially in metastatic breast cancer. To overcome the challenge of their xenotransplantation, the authors combined several advanced technologies to enrich and isolate CTCs from patients. These isolated CTCs were then injected into zebrafish embryos, allowing the researchers to study their dissemination pattern in vivo in a pilot study. Experiments showed that DanioCTC successfully enabled the xenografting of CTCs from patients. CTCs were primarily localized in the head and trunk regions of the zebrafish embryos. Overall, DanioCTC is a novel workflow to inject patient-derived CTCs into zebrafish, paving the way for a better understanding of the biology of metastatic breast cancer and the development of targeted interventions. ABSTRACT: Circulating tumor cells (CTCs) serve as crucial metastatic precursor cells, but their study in animal models has been hindered by their low numbers. To address this challenge, we present DanioCTC, an innovative xenograft workflow that overcomes the scarcity of patient-derived CTCs in animal models. By combining diagnostic leukapheresis (DLA), the Parsortix microfluidic system, flow cytometry, and the CellCelector setup, DanioCTC effectively enriches and isolates CTCs from metastatic breast cancer (MBC) patients for injection into zebrafish embryos. Validation experiments confirmed that MDA-MB-231 cells, transplanted following the standard protocol, localized frequently in the head and blood-forming regions of the zebrafish host. Notably, when MDA-MB-231 cells spiked (i.e., supplemented) into DLA aliquots were processed using DanioCTC, the cell dissemination patterns remained consistent. Successful xenografting of CTCs from a MBC patient revealed their primary localization in the head and trunk regions of zebrafish embryos. DanioCTC represents a major step forward in the endeavors to study the dissemination of individual and rare patient-derived CTCs, thereby enhancing our understanding of metastatic breast cancer biology and facilitating the development of targeted interventions in MBC. Summary statement: DanioCTC is a novel workflow to inject patient-derived CTCs into zebrafish, enabling studies of the capacity of these rare tumor cells to induce metastases.