Organotypic three-dimensional cancer cell cultures mirror drug responses in vivo : lessons learned from the inhibition of EGFR signaling

// Nico Jacobi 1 , Rita Seeboeck 2 , Elisabeth Hofmann 2 , Helmut Schweiger 1 , Veronika Smolinska 1 , Thomas Mohr 3 , Alexandra Boyer 1 , Wolfgang Sommergruber 4 , Peter Lechner 5 , Corina Pichler-Huebschmann 5 , Kamil Onder 6, 7 , Harald Hundsberger 2 , Christoph Wiesner 2 and Andreas Eger 1, 2 1 IMC University of Applied Sciences Krems, Department Life Sciences, Research Institute for Applied Bioanalytics and Drug Development, A-3500 Krems, Austria 2 IMC University of Applied Sciences Krems, Department Life Sciences, Institute of Medical and Pharmaceutical Biotechnology, A-3500 Krems, Austria 3 Medical University of Vienna, Institute for Cancer Research, A-1090 Vienna, Austria 4 Boehringer Ingelheim, RCV GmbH and Co KG, A-1121 Vienna, Austria 5 University Clinic Tulln, Department Surgery, A-3430 Tulln, Austria 6 Research Program for Rational Drug Design in Dermatology and Rheumatology, Department of Dermatology, Paracelsus Medical University of Salzburg, A-5020 Salzburg, Austria 7 ProComCure Biotech, A-5081 Anif, Austria Correspondence to: Andreas Eger, email: andreas.eger@fh-krems.ac.at Keywords: drug discovery; 3D models; ERBB signaling; targeted drugs; oncogene addiction Received: August 25, 2017      Accepted: October 27, 2017      Published: November 17, 2017 ABSTRACT Complex three-dimensional (3D) in vitro models that recapitulate human tumor biology are essential to understand the pathophysiology of the disease and to aid in the discovery of novel anti-cancer therapies. 3D organotypic cultures exhibit intercellular communication, nutrient and oxygen gradients, and cell polarity that is lacking in two-dimensional (2D) monolayer cultures. In the present study, we demonstrate that 2D and 3D cancer models exhibit different drug sensitivities towards both targeted inhibitors of EGFR signaling and broad acting cytotoxic agents. Changes in the kinase activities of ErbB family members and differential expression of apoptosis- and survival-associated genes before and after drug treatment may account for the differential drug sensitivities. Importantly, EGFR oncoprotein addiction was evident only in the 3D cultures mirroring the effect of EGFR inhibition in the clinic. Furthermore, targeted drug efficacy was strongly increased when incorporating cancer-associated fibroblasts into the 3D cultures. Taken together, we provide conclusive evidence that complex 3D cultures are more predictive of the clinical outcome than their 2D counterparts. In the future, 3D cultures will be instrumental for understanding the mode of action of drugs, identifying genotype-drug response relationships and developing patient-specific and personalized cancer treatments.