Three-dimensional tumor spheroid models in cancer research

Reconstructing the tumor microenvironment is a main issue in the development of experimental model for cancer. To provide a reliable tool for drug development and for personalized cancer therapy, it is important to keep key features that characterize the original tumor. In addition to this effort, three-dimensional (3D) cellular models are being thoroughly studied. Spheroids are self-assembled cell aggregates that have the capacity to possess many important components of the physiological spatial growth and cell-cell interactions. These 3D entities create ex vivo micro-tissues with metabolic activity that is governed by nutrient and oxygen diffusion mechanisms similar to hypoxic micro-tumors in vivo that are known to negatively affect the sensitivity of the tumor to anti-cancer drugs, and contribute to the acquired resistance. To this point our findings conclude that the 3D model of hybrid spheroids may be successfully constructed, but since each tumor type generates different interactions with its neighbour cells, there is a need of a platform for personalized medicine that would account for these differences. Such a model would provide the basis for complex multicellular tumors and stromal structures, to be used as a more reliable prediction method of biological processes and drug efficacy.