Abstract 5098: In vitro designer microenvironments for modeling the endothelin axis in brain cancer

Abstract

Abstract Preclinical studies in vivo have demonstrated that the endothelin (ET) axis is implicated in drug resistance of several tumors (e.g. brain and ovarian). Indeed, antagonists, blocking the binding of endothelin-1 to endothelin receptors (ETRs) overexpressed by cancer cells, have shown to make tumors more sensitive to conventional chemotherapies. In vitro, however, mechanistic studies have been hampered by the lack of adequate models, in which cell lines sufficiently express all key elements of the ET axis (e.g. ETRs), as they do in xenografts. We argue that limitations of conventional in vitro systems are mainly due to their inability to take into account the role of the extracellular microenvironment (ME). To overcome these limitations we have exploited the design flexibility of the QGel Matrix technology to identify 3D cell microenvironments that induced cancer cells to naturally express ETRs in vitro. Briefly, brain cancer cells LN229 were grown clonogenically in differently functionalized poly(ethylene glycol) (PEG)-based gels whose biological and biophysical characteristics were combinatorially varied. AlamarBlue™ assays and intracellular calcium release measurements (ICRM) were employed to measure cell growth and functionality of ETRs in the different gel ME over time. All assays were performed in 384-well plate format with liquid handling devices. ETR expression and functionality was confirmed in control cell lines when grown as clonogenic spheroids in MEs or as monolayer on tissue culture plastic (2D). Likewise, LN229 growth was observed in all tested MEs and in 2D. However, ETR functionality of LN229 differed considerably depending on the ME. For instance, in 2D, ICRM did not show ETR functionality. In contrast, clonogenically grown cell spheroids, in gel MEs containing cell integrin binding sites, showed significantly higher ETR functionality compared to LN229 in control gel MEs. Ongoing studies are further investigating the influence of other matrix characteristics (stiffness and degradability) to optimise expression and functionality of ETRs by LN229 for drug testing applications. These data suggest that engineered MEs are powerful tools for the development of cell-based assays with enhanced physiological relevance. With their proven compatibility with standard laboratory automation systems and assay miniaturization, these in vitro disease models can be translated to industry for making more relevant decisions on compound efficacy in preclinical tests. Citation Format: Simone C. Rizzi, Charlotte Mermier, Sophie Crettaz, Valeria Blumer-Nesca, Céline Gandar. In vitro designer microenvironments for modeling the endothelin axis in brain cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5098.