Study of the effects of various cryopreservation methods on viability of human gastrointestinal tumor xenografts in in vivo models

Background. Modern research requires access to tumor models for various types of studies on a single patient xenograft. Biobanks store tissue fragments and cell cultures for various studies, and it is necessary to form protocols for cryopreservation of various tumor fragments and create collections of biomaterial. Material and methods. The study was performed on tumor material from patients with malignant gastrointestinal tumors (esophagus, stomach, and colon). An experiment included 90 Balb/c Nude mice. The third generation of a PDX model was used for cryopreservation. The effectiveness of 3 protocols for cryopreservation of tumor tissue was evaluated using RPMI nutrient medium, fetal bovine serum (FBS), dimethyl sulfoxide (DMSO) and Mr. Frosty containers. 90 days after the freezing of the tumor nodes, the samples were thawed and implanted to animals; engraftment was noted, and the onset of tumor nodes in animals was recorded. At the end of the experiment, the data were analyzed statistically. Results. Protocol 1 was the least suitable for preserving fragments of esophageal, colon, and gastric tumors. Protocols 2 and 3 showed higher engraftment rates. The lowest engraftment rate was registered for reanimated gastric cancer PDXs. Conclusions. Protocols 2 and 3 with slow freezing of samples should be used for cryopreservation of human esophageal and colon cancer xenografts. Gastric cancer PDXs require other cryopreservation methods due to the low efficiency of the existing ones.

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