Mesenchymal Stem Cells Relevance in Multicellular Bioengineered 3D In Vitro Tumor Models

In vitro 3D tumor microenvironment mimicking models are gathering momentum as alternatives to traditional 2D flat monolayer cultures due to their potential for recapitulating major cancer hallmarks. To fulfill such potential, it is crucial that 3D tumor testing platforms completely emulate in vitro the complex in vivo tumor niche and its cellular constituents. Mesenchymal stem cells (MSCs) are recognized to play a pivotal multi-modulatory role in cancer, generating interest as biological targets and as key tumor suppressing, or tumor promoting effectors. This review discusses the biological influence of different types of MSCs in the tumor microenvironment and showcases recent studies that engineer 3D MSCs-cancer cells co-cultures as advanced in vitro therapy testing platforms. A special focus is given to MSCs-cancer 3D co-culture set-up parameters, challenges, and future opportunities. Understanding cancer-MSCs crosstalk and their underlying effects is envisioned to support the development of advanced 3D in vitro disease models for discovery of forefront cancer treatments.