Objective
To meet the need for improved
approaches to study cancer in vitro, there has been a surge in the
development of novel research models utilizing advanced culture methods. These
methods permit in vitro growth of cancer types previously not possible,
and/or models with enhanced in vivo relevancy compared to traditional
continuous cell lines. However, availability of these early-stage research
models is currently limited and there is a lack of data on the ability to scale
up production of these models to support the needs of the global research
community. We sought to investigate the protocols, expansion capacity,
cryopreservation ability, genetic stability, and feasibility of larger-scale
bioproduction of a subset of the models generated by the Human Cancer Models
Initiative (HCMI), an international collaborative effort between Cancer
Research UK, the foundation Hubrecht Organoid Technology, the National Cancer
Institute, and the Wellcome Sanger Institute. The HCMI’s initial goal is the
development of 1,000 novel human cancer models, paired with bioinformatics and
patient clinical data, particularly from rare or underrepresented cancer types.
One advanced culture method being utilized, three-dimensional organoid “microtissue”
culture, potentially poses challenges for traditional large-scale bioproduction
processes. It requires growth embedded within an undefined extracellular matrix
and complex media formulations containing multiple small molecules and
recombinant proteins with unknown stability and shelf-life. Additionally,
organoid growth media typically includes multiple sources of undefined
conditioned media containing critical growth factors. We cultured organoid
models derived from human colon, pancreas, esophagus, and mammary tissues
developed by laboratories contributing to the HCMI. Multiple unique donors were
available for all tissues and both cancer and non-cancer models were available
for two tissue types. Most models were maintained in culture continuously for
at least 60 days (7-27 population doublings, > 10 passages). Tissue and
donor variability was evident in model characteristics, including morphology
(assessed by microscopy and immunocytochemistry), growth rate, and genetic
stability (measured by short tandem repeats analysis). All models were amenable
to scale up beyond multiwell plates, and all models could recover from
cryopreservation. While organoid culture represents a significant divergence
from typical two-dimensional monolayer culture of continuous cell lines, our
results show that these next-generation in vitro models are suitable for
larger-scale bioproduction. This is vital to ensure the widespread availability
of these models within the research community to facilitate applications like
pre-clinical drug discovery and basic cancer research.