Exogenous Recombinant N-Acetylgalactosamine-4-Sulfatase (Arylsulfatase B; ARSB) Inhibits Progression of B16F10 Cutaneous Melanomas and Modulates Cell Signaling

Abstract

In the syngeneic, subcutaneous B16F10 mouse model of malignant melanoma, treatment with exogenous ARSB markedly reduced tumor size and extended survival. In vivo experiments showed that local treatment with exogenous N-acetylgalactosamine-4-sulfatase (Arylsulfatase B; ARSB) led to reduced tumor growth over time (p<0.0001) and improved the probability of survival up to 21 days (p=0.0391). Tumor tissue from the treated mice had lower chondroitin 4-sulfate (C4S) content and lower sulfotransferase activity. The free galectin-3 declined, and the SHP2 activity increased, due to altered binding with chondroitin 4-sulfate. These changes induced effects on transcription, which were mediated by Sp1, phospho-ERK1/2, and phospho-p38 MAPK. Reduced mRNA expression of chondroitin sulfate proteoglycan 4 (CSPG4), chondroitin sulfotransferase 15 (N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase), and matrix metalloproteinases 2 and 9 resulted. Experiments in the human melanoma cell line A375 demonstrated similar responses to exogenous ARSB as in the tumors, and inverse effects followed RNA silencing. ARSB, which removes the 4-sulfate group at the non-reducing end of C4S, acts as a tumor suppressor, and treatment with exogenous ARSB impacts on vital cell signaling and reduces the expression of critical genes associated with melanoma progression. HighlightsExogenous ARSB reduced tumor size and increased survival Chondroitin 4-sulfate increased, leading to increased free galectin-3 mRNA expression of CSPG4 and CHST15 declined following ARSB treatment mRNA expression of MMP9 and pro-MMP2 declined following ARSB treatment Active SHP2 increased, leading to declines in phospho-ERK1/2 and phospho-p38 MAPK