Xenografts using cancer cell lines in immunocompromised animal models have been used in research for many years, however there are concerns that these models do not adequately reflect the heterogeneity of an actual patient tumour. To overcome this patient-derived xenograft models (PDXs) have emerged as an important tool in drug discovery [1]. These models use cells directly derived from a patient’s tumour with limited clonal expansion in culture. These models do not however, represent the tumour immune microenvironment which can be modelled with syngeneic mice or newer human organoid or 3D systems, and organ-on-chip approaches.
PDX, syngeneic, 3D, and organ-on-chip in most cases rely on deep-frozen cell banks to preserve tumour samples before use in experiments. This necessitates the use of a freeze media to prevent the formation of cell damaging ice crystals which is often accomplished using 10% DMSO combined with serum or culture media prepared in-house.
BioLife Solutions is a developer, manufacturer and supplier of proprietary clinical grade cell and tissue hypothermic storage and cryopreservation freeze media for cells and tissues [2]. BioLife Solutions, Inc. has developed the proprietary cGMP CryoStor® fully defined serum-free DMSO cell freeze media as an alternative to in-house freeze media.
The CryoStor media was recently tested against in-house freeze media for the preservation and revival of PDX tumors. The key findings were as follows [3]:
- Engraftment: CryoStor 82% vs. in-house 39%
- Time to tumor formation: CryoStor 24 days vs. in-house 54 days
- Time to PDX harvest: CryoStor 64 days vs. in-house 89 days
- Potential loss of unique PDX lines: CryoStor 9% vs. in-house 35%
The use of a cGMP standardised freeze media across studies may also improve comparability.
Sources
- Pompili L, Porru M, Caruso C, Biroccio A, Leonetti C. Patient-derived xenografts: a relevant preclinical model for drug development. J Exp Clin Cancer Res. 2016; 35(1):189. Review. PubMed PMID: 27919280
- https://www.prnewswire.com/news-releases/biolife-solutions-cryostor-cell-freeze-media-highlighted-in-mayo-clinicmd-anderson-journal-article-on-preservation-of-patient-derived-xenografts-for-cancer-research-300612911.html
- Ivanics T, et al. Patient-derived xenograft cryopreservation and reanimation outcomes are dependent on cryoprotectant type. Lab Invest. 2018 doi: 10.1038/s41374-018-0042-7. PubMed PMID: 29520054
