Arylsulfatase B Regulates Versican Expression by Galectin-3 and AP-1 Mediated Transcriptional Effects

Arylsulfatase B (N-acetylgalactosamine-4-sulfatase; ARSB) removes 4-sulfate groups from chondroitin-4-sulfate (C4S) and dermatan sulfate and is required for their degradation. In human prostate stromal and epithelial cells, when ARSB was silenced, C4S, versican, and versican promoter activity increased, and the galectin-3 that co-immunoprecipitated with C4S declined. Galectin-3 silencing inhibited the ARSB-silencing induced increases in versican and versican promoter, due to effects on the AP-1 binding site in the versican promoter. These findings demonstrate for the first time the transcriptional mechanism whereby ARSB can regulate expression of an extracellular matrix proteoglycan with C4S attachments. In addition, following ARSB silencing, C4S that co-immunoprecipitated with versican increased, whereas co-immunoprecipitated EGFR declined, total EGFR increased, and exogenous EGF-induced cell proliferation increased, suggesting profound effects of ARSB on vital cell processes.