Hyaluronic acid-based hydrogels as 3D matrices for in vitro tumor engineering

Cancer cells cultured in vitro in biologically relevant three-dimensional (3D) matrices are likely to recapture the essential oncological features of the native tumor tissues. In this study, a hyaluronic acid (HA)-based, bilayer hydrogel system was engineered to support tumoroid formation from LNCaP prostate cancer cells. To prepare the hydrogel, HA derivatives containing either acrylate groups (HA-AC) or reactive thiols (HA-SH) were synthesized and characterized. Simple mixing of HA-AC and HA-SH resulted in the formation of viscoelastic gels under physiological conditions. The top hydrogel layer contains heparin (HP) decorated, HA-based hydrogel particles (HGPs) presenting a strong mitogen, heparin-binding epidermal growth factor-like growth factor (HB-EGF) in a sustained manner. LNCaP cells were embedded within the bottom hydrogel layer and receive growth stimuli from the top. The bilayer hydrogel construct simulates the interaction between tumor associated stroma and cancer cells in vivo via the programmed growth factor release. Spherical tumoroids with an average size of approximately 100 μm were detected after 7 days of culture. The HA-based, bilayer hydrogel system provides a useful platform for the study of tumor biology and the screening of anticancer drugs and their delivery systems.