Category: Assay Development and Screening
Three-dimensional (3D) cancer models are gaining attention as pre-clinical cancer models to bridge the gap between in vitro drug development research and the translation to in vivo and clinically applied treatments. With the aim to develop a platform for drug screening and studying drug efficacy in colorectal carcinoma (CRC) cells, we optimized a 3D co-culture sphere system, in which the following components were integrated: (i) spheres composed of patient-derived CRC cells, (ii) co-culture spheres consisting of CRC cells interspersed with endothelial cells (ECs) and fibroblasts (FBs), two major cell types interacting with tumor cells in the micro-environment; and finally (iii) spheres of healthy colorectal epithelial cells (CCD841) - to create opportunities for a therapeutic window.
Sphere cultures were established for a panel of patient-derived cell lines, each unique in mutations and drug response, to mimic the diversity observed in colorectal cancer patients. The 3D spheres are characterized by spatial-temporal organization of the cells, multi-dimensional cell-cell interaction and gradients of oxygen and nutrients. This system mimics more closely the compact cell growth and regional differences observed in tumors and as such has in increased physiological relevance as compared to 2D cell cultures. Our in vitro 3D sphere co-culture system is scaffold-free, forms reproducible single 3D (co-)culture spheroids and can be used for drug screenings. Characterizing of intra-spheroid distribution of the endothelial cells and fibroblasts revealed structures and pockets of FBs and ECs surrounded by tumor cells.
To evaluate the use of these cultures for screening and studying drug efficacy, the 3D sphere (co-)cultures were treated for 72h with drugs clinically used for CRC management: erlotinib and regorafenib, targeting EGFR and VEGFR2-3/Ret/Kit/PDGFR/Raf, respectively; as well as 5-fluorouracil (5-FU), a chemotherapeutic drug. Comparing treatment of 2D vs. 3D (co-)cultures, most notably, decreased viability of 3D spheres was observed after treatment with erlotinib compared to 2D cultures. Moreover, when treated with drug combinations, both cell culture system and cell-line dependent variations in drug-drug interactions were observed. In addition, low-dose drug combinations could obtain similar efficacy compared to a single 10-60x higher dose 5-FU positive control and this could be even further improved after retreatment for an additional 48h. Taken together, drug combinations tested on the 3D and 3D co-cultures could effectively inhibit 3D growth, and both interactions with surrounding cells as well as unique cell type dependent sphere characteristics can contribute to drug efficacy and may augment drug-drug interactions.
In conclusion, with the additional complexities, 3D and 3D co-cultures could provide a relevant system to screen and study (multi-)drug activity to both increase the potential of obtaining clinically relevant drug efficacy, as well as mimic the personalized treatment of colorectal cancer.
Marloes Zoetemelk– PhD student, School of Pharmaceutical Sciences, University of Geneva, Geneve, Geneve, Switzerland
School of Pharmaceutical Sciences, University of Geneva
Geneve, Geneve, Switzerland
Marloes Zoetemelk previouly obtained a B.Sc. in biomedical research followed by a M.Sc. in Oncology and is currently a PhD student in the Molecular Pharmacology Group of assistent professor Patrycja Nowak-Sliwinska at the School of Pharmacy of the University of Geneva in Switzerland. During her studies and internships undertaken in the Netherlands, USA and Austria she speciallized in multi-color constructs and vesicle research. Her current focus includes optimization of drug combinations relevant for clinical translation and personalized treatment on colorectal cancer (3D) cultures and patient-derived freshly isolated tumor cells.