Abstract 2442: Chondroitin sulfatases and transcription factors Gli, Tcf/Lef, and c-Myc in prostate stem cells

Abstract

Abstract The enzymes arylsulfatase B (ARSB; N-acetylgalactosamine-4-sulfatase) and galactose-6-sulfate sulfatase (GALNS; N-acetylgalactosamine-6-sulfatase) remove either the 4-sulfate group at the non-reducing end of chondroitin 4-sulfate (C4S) and dermatan sulfate, or the 6-sulfate group of chondroitin 6-sulfate, chondroitin 4,6-disulfate (chondroitin sulfate E), or keratan sulfate. In normal and malignant prostate tissues obtained by laser-capture microdissection, ARSB expression is greater in stroma than epithelium and GALNS expression is greater in epithelium than stroma. In malignant epithelium, GALNS expression is greater and ARSB expression is less than in normal epithelium. In cultured, normal human prostate stem and epithelial cells, ARSB silencing and GALNS overexpression exert similar signaling effects, attributable to enhanced binding of C4S with SHP2 (PTPN11), leading to SHP2 inhibition and sustained phosphorylation of phospho-ERK1/2 and other critical signaling molecules. Experiments in developing rat prostate showed that exposure to estrogen significantly reduced ARSB activity, whereas GALNS activity increased at post-natal day 30. To further assess how changes in sulfatases may contribute to prostate development, transcription factor activation profiling plate arrays (Signosis) were performed in cultured human prostate stem cells (CRL-2887, ATCC). Cells were silenced for ARSB (EC 3.1.6.12) or GALNS (EC 3.1.6.4) by specific siRNA (Qiagen) or ARSB was overexpressed [for ARSB (NCBI NM_000046, transcript variant 1; for GALNS (NCBI NM_000512; TrueClone, Origene] by transfection of specific untagged plasmids. Biotin-labeled transcription factor probes based on the known DNA-binding consensus sequences were detected in nuclear extracts of the treated and control stem cell preparations. Nuclear DNA bound transcription factor Gli declined 35% when ARSB was silenced and 63% when GALNS was overexpressed. Inversely, nuclear bound Gli increased 62% when ARSB was overexpressed and 42% when GALNS was silenced. These findings are consistent with the observed inverse signaling effects of ARSB and GALNS in the prostate cells. Also, Gli mRNA expression was 3.50 ± 0.22 times greater in non-malignant epithelium than in malignant epithelium, consistent with decline when GALNS is greater and ARSB is reduced. Nuclear binding of TCF/Lef and c-Myc showed inverse effects in relation to GALNS silencing and overexpression, declining when GALNS was silenced and increasing when GALNS was overexpressed. These effects are consistent with the observed effects on Wnt signaling. These observations indicate that changes in chondroitin sulfates mediated by chondroitin sulfatases may have profound consequences on developmental programming in prostate tissue and suggest that hormonal-mediated effects may be transcribed through changes in sulfatases and chondroitin sulfates. Citation Format: Joanne Kramer Tobacman, Sumit Bhattacharyya, Leo Feferman. Chondroitin sulfatases and transcription factors Gli, Tcf/Lef, and c-Myc in prostate stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2442.