Material properties of disulfide-crosslinked hyaluronic acid hydrogels influence prostate cancer cell growth and metabolism†
Cells reside in vivo within three dimensional environments in which they interact with extracellular matrices (ECMs) that play an integral role in maintaining tissue homeostasis and preventing tumour growth. Thus, tissue culture approaches that more faithfully reproduce these interactions with the ECM are needed to study cancer development and progression. Many materials exist for modeling tissue environments, and the effects of differing mechanical, physical, and biochemical properties of such materials on cell behaviour are often intricately coupled and difficult to tease apart. Here, an optimized protocol was developed to generate low reaction volume disulfide-crosslinked hyaluronic acid (HA) hydrogels for use in cell culture applications to relate the properties of ECM materials to cell signalling and behaviour. Mechanically, HA hydrogels are comparable to other soft hydrogel materials such as Matrigel and agarose or to tissues lacking type I collagen and other fibrillar ECM components. The diffusion of soluble materials in these hydrogels is affected by unique mass transfer properties. Specifically, HA hydrogel concentration affects the diffusion of anionic particles above 500 kDa, whereas diffusion of smaller particles appears unimpeded by HA content, likely reflecting hydrogel pore size. The HA hydrogels have a strong exclusion effect that limits the movement of proteins into and out of the material once fully formed. Such mass transfer properties have interesting implications for cell culture, as they ultimately affect access to nutrients and the distribution of signalling molecules, affecting nutrient sensing and metabolic activity. The use of disulfide-crosslinked HA hydrogels for the culture of the model prostate cancer cell lines PC3 and LNCaP reveals correlations of protein activation linked to metabolic flux, which parallel and can thus potentially provide insights into cell survival mechanisms in response to starvation that occurs in cancer cell microenvironments.