Introduction: Monolayer cultures on tissue culture plastic do not accurately mimic the cancer environment and often provide a poor prediction of whether a drug will yield clinical benefit. By contrast, when prostate cancer cells are cultured as 3D aggregates their response to chemotherapy agents more realistically parallels the in vivo response. In addition, the microenvironment in which prostate cancer cells reside, particularly the stromal cell populations, has the potential to significantly influence prostate cell behaviour and contribute to cancer progression. We have developed a high-throughput 3D prostate cancer-stromal cell micro-aggregate co-culture system suitable for drug testing.
Methods: Micro-aggregates of uniform diameter (100-200µm) are cultured on a PDMS micro-well surface. Prior to cell seeding, the PDMS micro-well surface is coated with poly-lysine and multi-layers of hyaluronan and chitosan, to minimize protein adsorption and subsequent cell attachment to the micro-well surface. The prostate cancer cells lines, LNCaP and RWPE-2 were seeded either in mono-culture or in co-culture with the fibroblast cell line, WPMY-1. The normal prostate cell line, RWPE-1, was used as a comparison.
Results and Discussion: In mono-culture, the micro-aggregates do not form a dead cell core, as shown by a live/dead stain. In addition, apical (E-Cad, β-catenin, aPKC) and basal (α6integrin, lam5) polarity markers show a random distribution throughout the aggregates. This poor cell organisation and lack of defined polarity is also seen in high grade cancer tissue samples. In co-culture, the RWPE-1 and-2 cells from an epithelial cell cluster surrounded by the WPMY-1 cells, and LNCaP cells have the inverse cell distribution. In summary, the prostate micro-aggregates can be used to model a prostate cancer stage prior to angiogenesis, before a dead cell core has formed. Furthermore, direct co-culture with stroma provides a means to study stromal-epithelial interactions in response to drug treatment.