A comparative study of freezing single cells and spheroids: towards a new model system for optimizing freezing protocols for cryobanking of human tumours.
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.
Ehrhart
F
F
Fraunhofer Institut für Biomedizinische Technik, Ensheimer Strasse 48, 66386 St. Ingbert, Germany.
Schulz
J C
JC
Katsen-Globa
A
A
Shirley
S G
SG
Reuter
D
D
Bach
F
F
Zimmermann
U
U
Zimmermann
H
H
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
D003451:Cryoprotective Agents; D014199:Trehalose