KLK3 and prostate cancer: While PSA was significantly lower (Figs. S8a and S9) in prostate cancer cells and co-cultures, genes associated with progression to aggressive disease and resistance to therapy9,29 were upregulated in both co-culture types: AR, DDC, and ENO2. Conversely, epithelial-to-mesenchymal transition-relevant genes (Slug, Snail, Zeb-1) were found unaltered under androgen deprivation in the co-cultures (not shown).