Premium
Decline in Arylsulfatase B and Overexpression of Galactose 6‐Sulfatase Both Increase DNA Methyltransferase Activity and Wnt Signaling in Prostate Stem Cells
Author(s) -
Bhattacharyya Sumit,
Feferman Leo,
Tobacman Joanne Kramer
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.583.2
Subject(s) - wnt signaling pathway , gene silencing , sulfatase , chemistry , dna methylation , chondroitin sulfate , cancer research , biology , microbiology and biotechnology , signal transduction , biochemistry , gene expression , enzyme , glycosaminoglycan , gene
The enzymes arylsulfatase B and galactose 6‐sulfatase remove sulfate groups from sulfated glycosaminoglycans. ARSB removes 4‐sulfate groups from chondroitin 4‐sulfate and dermatan sulfate, and GALNS removes 6‐sulfate groups from chondroitin 6‐sulfate and keratan sulfate. In neonatal rat prostate, arylsulfatase B was predominant in the stroma, and GALNS in the epithelium. Other findings have demonstrated transcriptional effects due to decline in ARSB and the associated increase in chondroitin 4‐sulfation, leading to reduced binding of galectin‐3 with chondroitin 4‐sulfate. Increased nuclear galectin‐3 interacted with transcription factors Sp1 to increase the transcription of Wnt9A. Other studies demonstrated increased Wnt signaling following decline in ARSB, with increased nuclear beta‐catenin, increased nuclear DNA binding of TCF/LEF and c‐myc and increased expression of c‐myc. In this study, effects on DKK3 expression and DNA methyltransferase were evaluated, to determine if reduced expression of DKK3, an inhibitor of Wnt signaling, contributed to the increase in Wnt signaling following ARSB silencing. Methods included: growing human prostate stem cells (ATCC), silencing DKK‐3 by siRNA, measuring DNMT activity, determining DKK3 expression, analysis of DKK3 promoter methylation, and analysis of effects on Wnt signaling. ARSB was silenced and overexpressed, and GALNS was silenced and overexpressed, as previously, and the effects ascertained by measurements of enzyme activity. The effects on DKK3 expression, DNMT activity and expression, and Wnt signaling were detemined. Findings included: increased DNMT activity following ARSB silencing and GALNS overexpression, decline in DKK3 promoter activation and DKK3 expression following ARSB silencing and GALNS overexpression. Since studies have shown ARSB predominance in stroma and GALNS in epithelium, the similar effects of GALNS overexpression and ARSB silencing suggest a profound interaction related to sulfatase activity and chondroitin sulfation. Both ARSB silencing and GALNS expression lead to relative increase of chondroitin 4‐sulfation vs. chondroitin 6‐sulfation. These findings suggest that developmental regulation related to wnt signaling may be mediated by changes in chondroitin sulfation and sulfatase activity.