Unlocking organoid potential through improved culture conditions

Refining organoid culture methods is key to creating lifelike models for drug discovery, cancer research, and therapy testing.

Yelena Bronevetsky, PhD and Xcell Biosciences

While scientists have been aware of the feasibility and importance of three-dimensional cell culturing since the 1980s, it’s only in recent years that the research community has made a concerted push to develop organoids. These miniature models, grown in culture to represent simplified versions of organs, have captured the attention of scientists around the world. Today, they are gaining traction among researchers in drug discovery and development for use in drug screening, preclinical testing, and cell therapy evaluation.

The push to invest in organoid development is especially timely as the US government is

actively seeking alternatives to animal testing for the drug review and approval process. While significant progress is still needed, organoids offer the potential to generate relevant, reliable information about how drugs interact with biological systems that could one day reduce or even eliminate the need for animal models in the preclinical testing phase of drug development.

Perhaps the greatest opportunity — and paradoxically the biggest challenge — in organoid research lies in making them as physiologically relevant as possible. With carefully optimized processes, organoids can closely mimic the response of in vivo organs, revealing valuable insights into the safety, efficacy and mechanisms of action of drug candidates. However, the best practices for culturing organoids to achieve this level of fidelity are still very much under development.

From cancer to neurology

From their start in academic labs to current use in biopharma, organoids have been created for a wide range of applications. Often built from pluripotent stem cells, organoids can model organs that are not easily accessible in a living patient — such as the brain — or processes that can’t be tested in vivo, such as targeted gene knockouts or knock-ins. Scientists have already gleaned new insights about neurological diseases from this approach.

Organoids are also commonly developed from patient cells to model diseases or conditions such as cancer, cystic fibrosis, inflammatory bowel disease, infectious diseases, and neurological disorders. For example, scientists used this technique to model polycystic kidney disease and discovered that organoids generated with patient cells formed more cysts than those derived from healthy cells. Interestingly, the same study also showed that changing physical components in the microenvironment around the organoid could increase or decrease cyst formation.

Of all the diseases organoids can model, cancer might be of greatest interest to biopharma scientists today. Generated from tumor biopsy samples, organoids have already been used to create in vitro versions of liver, breast, lung, prostate, and gastrointestinal cancers, among others. Unlike traditional cell lines, organoids reflect the heterogeneity seen in real cancers, making them a valuable asset for characterizing biology and for testing new drug candidates.

Advances in organoid culture

Even scientific leaders in the organoid field today are struggling to define the optimal culture conditions needed to accurately mirror in vivo biology. Part of the challenge is due to tailoring conditions to each specific organoid, and another stems from the broader difficulty of recreating 3D cultures in a physiologically relevant in vitro environment.

A recent breakthrough came from scientists at the Swiss Federal Technology Institute of Lausanne, who developed a novel culture platform aimed at advancing immunotherapy and evaluating tumor-infiltrating lymphocyte candidates. Their system uses arrays of hydrogel films in 96-well plates, with each organoid grown in a 500 μm microcavity in a well. “Unlike conventional organoid cultures, this system allows for highly efficient cell aggregation at pre- defined positions in a matrix-free setting, leading to exceptionally homogeneous organoid formation,” the team reported. Benefits include increased interactions among cells within the organoid, more reliable tracking of each organoid over time, and high-resolution imaging analysis at scale. The technique also supports the creation of more complex microenvironments with a higher diversity of cellular components than traditional methods typically allow.

In addition to structural advances like microcavities, scientists are also working to refine culture conditions so that organoids are more reflective of native biology. An important part of this would be the ability to control more conditions than standard incubators allow. For example, replicating the oxygen levels and pressure dynamics present during early lung development has been shown to enhance the complexity of induced pluripotent stem cell-derived alveolar lung organoids, yielding greater branching and a more accurate representation of distal lung architecture.

Adjusting these parameters can also increase the potency and persistence of cell therapy candidates by more closely matching the environments they will encounter in patients. Researchers are already conducting studies to determine the oxygen and pressure levels that yield the most realistic results from cell therapies used with organoid models. Looking ahead, advanced incubation platforms with tunable pressure and hypoxia parameters could enable scientists to create more lifelike culture conditions and generate more representative data from organoid studies for a broad range of applications.

The future of organoid technology

Driven by a need for more reliable preclinical models paired with regulatory guidance to move away from animal testing, organoids are poised to become a critical asset for drug discovery and development scientists. They are already being studied for cell and gene therapies and for cancer therapies, but these in vitro models have the potential to be useful across many other diseases and therapy classes. Unlocking that potential will depend heavily on researchers’ ability to overcome current challenges in culturing conditions to make organoids as physiologically relevant as possible.

This article was contributed by Yelena Bronevetsky, Director of Product Management at Xcell Biosciences.