User:Leofef/sandbox

Arylsulfatase B was recently studied as a potential biomarker of prostate cancer

Halley's comet caused a famine

Possible role in development of diabetes
Recent study showed that mice that consumed carrageenan in their drinking water had insulin resistance and abnormal glucose tolerance test. In addition, inhibition of the insulin receptor signaling pathway was demonstrated in the livers of carrageenan-fed mice and carrageenan-treated HepG2 cells. Results of the study demonstrate extra-colonic manifestations of carrageenan and suggest that carrageenan in the diet may contribute to development of diabetes

Role in cystic fibrosis
Expression and activity of ARSB were found to be related to the function of cystic fibrosis transmembrane conductance regulator (CFTR), the membrane channel deficient in cystic fibrosis. Measurements in cystic fibrosis cell line IB3 and its derivative cell line C38, which has a functional CFTR, showed increased ARSB activity and expression in the C38 line. CFTR potentiator VRT-532 increased ARSB expression and activity in cystic fibrosis cells to the level in the normal bronchial epithelial cells.

Extra-lysosomal localization
Although primarily a lysosomal enzyme, ARSB was also found to localize at the cell membrane of hepatocytes, sinusoidal endothelial cells, and Kupffer cells in the liver, as well as in the apical membranes of normal and malignant colonic and prostatic epithelial cells, by immunohistochemistry and immunofluorescence studies. Membrane immunostaining in the colon and prostate was lower in malignant than in normal tissue and also was lower in higher grade malignancies.

Role in malignancy
ARSB has been studied in a variety of cancers. Cultured normal mammary epithelial and myoepithelial cells had significantly higher ARSB activity than cultured malignant mammary cells. Immunohistochemistry in the colon showed decreased membrane ARSB staining in colon cancer compared to normal colon, as well as in higher grade malignancies. ARSB activity was lower in malignant than normal prostate tissue, and immunostaining of prostate tissue microarrays showed not only decreasing ARSB staining in prostate cancer tissue of a higher Gleason score, but also lower staining in patients with recurrent compared to non-recurrent cancer. ARSB staining was a greater predictor of recurrence than Prostate-specific antigen (PSA) test, indicating possible future role of ARSB as a prognostic biomarker of prostate cancer. Further evidence of ARSB as a tumor suppressor was determined by molecular studies in cell cultures where ARSB was silenced by siRNA. The studies showed that decrease of ARSB leads to increase in free galectin-3, which attaches more strongly to less sulfated chondroitin 4-sulfate. Galectin-3 then acts on transcription factors AP-1 to increase expression of chondroitin sulfate proteoglycan versican and SP-1 to increase expression of WNT9A. Another mechanism by which reduced ARSB is associated with carcinogenesis is through increased binding of SHP2 to more sulfated chondroitin 4-sulfate, which leads to increased phosphorylation of p38 and MITF with subsequently increased expression of GPNMB. In melanoma cells and normal melanocytes, ARSB silencing increased invasiveness and expression of CSPG4 and MMP2, known markers of melanoma progression. CSPG4 expression was mediated by reduced binding of galectin-3 to C4S, while MMP2 expression was mediated by increased binding of SHP2 to C4S.

Role in metabolism
Reduced sulfate availability due to impaired activity of ARSB has been linked to increased aerobic glycolysis, as shown by an increase in  NADH and  NADPH, reduced oxygen consumption, increased extracellular acidification and  serum  lactate, and a decline in  mitochondrial membrane potential in ARSB-silenced cells and ARSB-null mouse tissues.