Developing tumor microenvironment in rotating human melanoma cell cultures: study of novel preclinical model

Abstract

More than 97% of anticancer drugs under investigation fail in vitro evaluation, while only 0.4% of drug candidates that pass this stage proceed to the clinical trials. The differences between cell morphology and physiology observed in vitro and in vivo make the selection of a drug candidate problematic: traditional in vitro cultures do not reflect tissue-like conditions. Here we aimed for developing and characterizing human melanoma tumorspheres cultured in rotating bioreactors as an alternative for in vitro modeling. Tumorspheres were characterized by in-depth confocal imaging and image cytometry, followed by quantitative analysis that was used for whole tumorspheres characterization. Cell viability and changes in proteins expression were investigated in single-cell analysis through the spectral flow cytometry followed by STRING interaction networks assessment. The tumorspheres showed the ability to grow for at least one month to reach millimeter sizes. In this way, it was possible to improve the morphology of tumorspheres and to observe changes in tumor microenvironment (TME) and the expression of key proteins. The advantage of the described models is the creation of perspectives for further development of maintaining cellular models that are hybrid systems combining the features of spheroids and organoids for preclinical and translational research.