3D bioprinting to build versatile ovarian tumor models for new anticancer drug development
Résumé
While relevant in vitro cancer models are crucial to efficiently develop new anticancer molecules, it is becoming now well established that two-dimensional cell cultures are far from reflecting the complexity and diversity of in vivo tumors and gtheir environment. Three-dimensional cell cultures are interesting alternatives due to their better ability to simulate cell-cell interactions and oxygen and nutrient gradients found in vivo. In this area, 3D bioprinting is considered as a promising approach to establish reproducible and robust 3D tumor models. Indeed, 3D bioprinting is a computer assisted process that generates 3D cell constructs with a well-defined architecture and a high reproducibility. Moreover, this technology makes it easy to associate several cell types in a single model to better simulate the cell diversity inherent to in vivo tumors.
In this work, 3D bioprinting was used to build an ovarian tumor model containing cancer cells and cancer-associated fibroblasts (CAFs) encapsulated in a gelatin-alginate hydrogel. The hydrogel composition was first optimized to ensure good printability at 37°C and a low extrusion pressure to minimize cell damage. Once the hydrogel optimized, it was used to encapsulate cells at a final density of l million cell/mL. The resulting “bio-ink” was then used to bio-print tumor-like constructs. These bioprinted tumor models were further characterized to assess the viability and the morphology of the encapsulated cells. The cell membrane integrity was assessed through Live-Dead labelling and confocal imaging. Alamar Blue assay and WST1 assay were preformed to evaluate cell metabolic activity and proliferation. Annexin V/PI labeling and flow cytometry analysis were also conducted to quantify the proportion of apoptotic cells within the bioprinted tumors. For further assessing cell morphology and distribution within the tumor models, bioprinted structures were fixed and 5 µm thickness sections were realized for hematoxylin and eosin (H&E) staining. Through these experiments, we could demonstrate that our bioprinted structures show high viability and maintained cell metabolic activity even 7 days after bioprinting. More interestingly, this work demonstrates that our bioprinted strucutres can easily be subjected to routinely used viability and histology assays making them very interesting as in vitro models for new anticancer drug development.