3D Bioprinting of Model Tissues That Mimic the Tumor Microenvironment

The tumor microenvironment (TME) influences cancer progression. Therefore, engineered TME models are being developed for fundamental research and anti-cancer drug screening. This paper reports the biofabrication of 3D-printed avascular structures that recapitulate several features of the TME. The tumor is represented by a hydrogel droplet uniformly loaded with breast cancer cells (10(6) cells/mL); it is embedded in the same type of hydrogel containing primary cells-tumor-associated fibroblasts isolated from the peritumoral environment and peripheral blood mononuclear cells. Hoechst staining of cryosectioned tissue constructs demonstrated that cells remodeled the hydrogel and remained viable for weeks. Histological sections revealed heterotypic aggregates of malignant and peritumoral cells; moreover, the constituent cells proliferated in vitro. To investigate the interactions responsible for the experimentally observed cellular rearrangements, we built lattice models of the bioprinted constructs and simulated their evolution using Metropolis Monte Carlo methods. Although unable to replicate the complexity of the TME, the approach presented here enables the self-assembly and co-culture of several cell types of the TME. Further studies will evaluate whether the bioprinted constructs can evolve in vivo in animal models. If they become connected to the host vasculature, they may turn into a fully organized TME.

Automated summary

This study introduces a biofabrication method for 3D-printed avascular structures that mimic features of the tumor microenvironment. Experimentally, cells were able to remodel the hydrogel and remain viable, with different cell types proliferating in vitro. Further research will assess the potential for these bioprinted structures to evolve in animal models and potentially transform into a fully organized tumor microenvironment if connected to host vasculature.