Annual Report 2020
Section of Support of Animal Experimentation
Toshio Imai
Introduction
The pivotal role of the Section of Support of Animal Experimentation is to establish cell culture/animal models (patient-derived 3D-cultured organoids and 2D-cultured fibroblasts, xenografts (PDXs)), which might accelerate the efficacy evaluation and the acquisition of non-clinical proof of concept (POC)/pharmacodynamic biomarkers for the development of novel anti-cancer drug candidates. In vivo and in vitro models derived from clinical tumor specimens are considered to more accurately reflect anti-cancer drugs in patients compared to models using conventionally established cancer cell lines. On the other hand, comparative analyses of patient-derived 2D/3D-cultured and xenograft systems have not yet been completely conducted, and we are now attempting to determine their characteristics.
The Team and What We Do
The establishment and characterization of 3D-cultured organoid and/or patient-derived xenograft (PDX) models of various types of cancers by our team will allow us to accrue knowledge and experience of case-by-case methodologies for their establishment and to construct a systematic library of organoids/PDXs with omics-based data sets.
Research activities
Gene mutation and gene expression patterns, which characterize each cancer case, were found to be almost as maintained in 3D-cultured organoids/PDXs as those in original clinical colorectal (CRC) cancer specimens, supporting the view that such patient-derived cancer models could more accurately reflect the effectiveness to anti-cancer drugs compared to conventionally established cancer cell lines. In addition, we established a co-culturing method of CRC organoids and paid cancer-associated fibroblasts (CAFs) in each case. This system enabled us to analyze cell viabilities, gene expressions and/or metabolites in both separated organoids and CAFs, and it was found that some gene expressions, e.g., REG family genes, which were expressed in the original cancer tissues, were significantly reduced in the single-cultured organoids, but were re-expressed by co-culturing with their paired CAFs.
Education
It is important to consider biological safety in handling not only the surgical specimens themselves but also the related biological resources including patient-derived organoids and xenografts. We contribute to consolidating the facility and rules to preserve such biological safety in an experiment environment and to conduct training for researchers and technical experts on cell/organoid culture and animal experiments. In addition, standardized/manualized procedures for establishment of PDXs and culturing of organoids are being prepared.
Future Prospects
In addition to the established CRC organoids, those derived from other types of cancers will be cultured and stocked as a library, to accelerate collaborative research with pharmaceutical companies and academia.
List of papers published in 2020
Journal
1. Naruse M, Ochiai M, Sekine S, Taniguchi H, Yoshida T, Ichikawa H, Sakamoto H, Kubo T, Matsumoto K, Ochiai A, Imai T. Re-expression of REG family and DUOXs genes in CRC organoids by co-culturing with CAFs. Sci Rep, 11:2077, 2021