title: A comparative study of freezing single cells and spheroids: towards a new model system for optimizing freezing protocols for cryobanking of human tumours.
abstract: Cryopreservation of human tumour cells and tissue is a valuable tool for retrospective analysis and for the transport and handling of biopsy material. Tumour tissue consists of different cell types, which have different optimal freezing conditions, and extracellular matrix. A well-defined and authentic model system is required for developing new freezing protocols and media. This work describes the use of L929 and PC-3 spheroids as new model systems for freezing human tumours. Cell suspension and spheroids were frozen in different vessels (1 ml cryovials and a special, cryo-compatible 30 x 25 microl multi well plate) at slow rate (1 degrees C/min). Freezing media were combinations of culture or tumour transport medium (Liforlab) with the cryoprotective agents, Me(2)SO, trehalose and modified starch. We also present a new method of evaluating the viability of three dimensional multicellular systems to compare thawed spheroids objectively. Best viability (70%) of L929 spheroids occurred with a combination of Liforlab and starch hydrolysis product. The best cryopreservation results for spheroids were found with extracellular cryoprotectants, while optimum viability of single cells was achieved with Me(2)SO.
authors.affiliation: Fraunhofer Institut für Biomedizinische Technik, Ensheimer Strasse 48, 66386 St. Ingbert, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Ehrhart
authors.forename: J C
authors.initials: JC
authors.lastname: Schulz
authors.forename: A
authors.initials: A
authors.lastname: Katsen-Globa
authors.forename: S G
authors.initials: SG
authors.lastname: Shirley
authors.forename: D
authors.initials: D
authors.lastname: Reuter
authors.forename: F
authors.initials: F
authors.lastname: Bach
authors.forename: U
authors.initials: U
authors.lastname: Zimmermann
authors.forename: H
authors.initials: H
authors.lastname: Zimmermann
mesh_terms: D000818:Animals; D049108:Cell Enlargement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000295:instrumentation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D006801:Humans; D051379:Mice; D018874:Spheroids, Cellular / Q000166:cytology* / Q000187:drug effects; D014199:Trehalose / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000166:cytology* / Q000187:drug effects
chemical_list: D003451:Cryoprotective Agents; D014199:Trehalose