Long-term cryopreservation reanimation success of pancreatobiliary patient-derived xenograft models.

Abstract

Patient-derived xenografts are cancer models where patient tumor tissue is implanted into immunocompromised mice for preclinical research. Patient-derived xenografts recapitulate the original patient tumor with high fidelity and highly correlate with treatment efficacy compared with cell lines or genetically engineered mice. Maintaining validated patient-derived xenograft libraries requires effective cryopreservation and reanimation techniques. While we previously demonstrated success using specialized cryoprotectant techniques after short-term preservation (<3 years), optimal long-term methods remain unclear. We investigated successful reanimation of validated pancreatobiliary patient-derived xenografts following long-term (>5 years) cryopreservation. From our patient-derived xenograft library of over 760 prospectively collected unique patient tumors, we utilized 32 random histopathologically confirmed pancreatic adenocarcinoma and cholangiocarcinoma tumors from validated second-generation patient-derived xenograft models that were cryopreserved >5 years. Growth was assessed up to 6 months. Upon reaching a volume of 500-1,000 mm³, tumors were harvested and histologically compared with the original patient tumor and first-generation patient-derived xenograft. The primary outcome was successful growth of long-term cryopreserved patient-derived xenograft tumors. Of the 14 pancreatic ductal adenocarcinoma and 18 cholangiocarcinoma patient-derived xenografts, 31 (96%) were successfully reanimated and validated after long-term cryopreservation with a 2-month median time to harvest. One model (3%) was unsuccessful. The original patient-derived xenograft models were derived from cancer tissue obtained at surgical resection 28 (87%) or biopsy 4 (13%). The median duration of cryopreservation was 8 years (range 6-11 years). Previously validated cryopreserved pancreatobiliary patient-derived xenograft tumor models were effectively reanimated from long-term (>5 years) cryopreservation at -80°C with a high success rate (>95%). Optimized protocols enable maintaining a cryoinventory of patient-derived xenograft models for future translational applications.