(717f) Acrylated Hyaluronic Acid Hydrogels to Study Cancer Angiogenesis

Many have adapted three dimensional (3D) tissue culture models that recapitulate aspects of the tumorogenic in vivo microenvironment to study cancer progression in vitro. For example, both hypoxia and matrix stiffness were shown to promote tumor growth.  We have previously engineered a modular culture system using hyaluronic acid (HA) hydrogel to engineer a functional microvascular network from endothelial progenitor cells (EPCs). The acrylated HA hydrogel is modified with binding adhesive domain (RGD) and matrix metallopeptidase (MMP) cleavable sites. Here we hypothesize that our tunable acrylated HA hydrogel system can be used to study cancer cell fate and its adaptive angiogenic responses.

Using mathematical modeling we first found that within 30 minutes of culture of HA-encapsulated HT1080 fibrosarcoma cells (5x10⁶ cells/ml) in 5% oxygen, oxygen tension gradient is generated from the HA hydrogel edge (~4%) to the center (~1%). Analyzing cell cycle, we discovered that the there is a reduced percentage  of Sub G1 population during three days period compared to atmospheric conditions, suggesting  that HT1080 cells rapidly recover from encapsulation-induced apoptosis at 5% oxygen.  Interestingly these were not significantly affected by altering the viscoelasticity of the HA hydrogel from 200 Pa to 30 Pa. Moreover, gene expression for MMP1, VEGF, ANG1 were altered across different viscoelasticity of gel only when cultured in 5% oxygen. This suggests that HT1080 cells in hypoxic conditions are more sensitive in responding to matrix stiffness compared to HT1080 cells cultured in atmospheric condition. Finally, based on these results, we also developed an angiogenesis assay to showcase cancer cell recruitment of EPC under different stiffness and oxygen tension. Here we are reporting a hydrogel system that can be incorporated with multidimensional parameters in investigating the cancer cell fate and its adaptive angiogenic responses in a 3D in vitro culture condition.