Fig 1: Chondroitin sulfotransferase (CHST) 15 (chondroitin 4-sulfate 6-O-sulfotransferase) is increased in malignant prostate epithelial tissue, in prostate tissue of ARSB-null mice, and in prostate epithelial cells when ARSB is reduced.(A) In laser-microdissected normal and malignant human prostate epithelium and stroma, CHST15 mRNA expression is increased in the malignant epithelial tissue compared to normal epithelial tissue (p < 0.001; n = 6). In the normal and malignant stroma, CHST15 expression is less than in the normal epithelium (p < 0.05; n = 6). (B) In the laser-microdissected prostate tissues, CHST15 protein detected by ELISA was significantly greater in the malignant prostate tissue (p < 0.001; n = 3). Stromal values are significantly less than in the normal epithelial tissue (p < 0.05; n = 3). (C) In prostate tissues from ARSB-null mice (Strain 005598, Jackson Labs), the CHST15 mRNA was significantly more than in the prostate tissue from normal C57BL/6J controls (p < 0.001; n = 6). (D) In cultured human prostate epithelial cells (CRL-2850, ATCC) treated with prostate stromal cell (CRL-2854, ATCC) spent media in 1:1 ratio with epithelial cell media, CHST15 expression increased following ARSB silencing by siRNA in the epithelial cells (p < 0.001; n = 6). Expression was significantly higher in the epithelial cells treated with control siRNA than in the stromal cells (p < 0.01; n = 6). (E) Correspondingly, the CHST15 protein determined by ELISA was significantly greater in the epithelial cells grown with spent media from the stromal cells in 1:1 combination with epithelial cell media and ARSB silencing by siRNA (p < 0.001; n = 3). [ARSB = arylsulfatase B; CHST = chondroitin sulfotransferase; SCM = prostate stromal cell spent media; si = siRNA; *** for p < 0.001 greater than control; ## for p < 0.01 and # for p < 0.05 less than control]