Optimization of three-dimensional (3D) in vitro assays for breast cancer drug screening

Sammanfattning

Matrix stiffness is recognized as a major factor when it comes to tumor progressionand cancer cell migration. Obtaining a relevant matrix stiffness when developing 3Din vitro models is therefore key in order to accurately replicate the cellular behaviorexhibited in human breast cancer tissue. In this study, DLP-bioprinting and grayscaleimage projection was used to create a multi-material, multi-stiffness 3D model witha stiffness range similar to that of tumorous and tumor-adjacent breast tissue. Byusing the BIONOVA X grayscale function, PhotoGel-INK 50% (CELLINK, GothenburgSweden) was exposed to an energy range between 70% and 100% (corresponding toapproximately 224 mJ/cm2 - 320 mJ/cm2) which generated a matrix with a stiffnessgradient between 3.5 - 5.2 kPa. The generated matrix promoted MDA-MB-231 cells toform spheroids and caused a progressive matrix reconstruction through both proteolyticdependentand proteolytic-independent invasion mechanisms. The cells in the MDAMB-231 spheroids also exhibited a migratory behavior consistent with literature as theymigrated towards the softer parts of the surrounding matrix. This study shows thatDLP-bioprinting and grayscale image projection can be used to create viable, multistiffness,3D in vitro models that accurately mimic the behavior of native breast cancertissue. These findings suggest that this model has the potential to serve as a steppingstone for future development of high-throughput in vitro assays for breast cancer drugscreening.