Cancer research

Neuroblastoma-derived sulfhydryl oxidase, a new member of the sulfhydryl oxidase/Quiescin6 family, regulates sensitization to interferon gamma-induced cell death in human neuroblastoma cells.

PMID 14633699


In neuroblastoma cells, apoptotic programs can be activated by cytokines and cytostatic drugs. Apoptotic dysfunction confers resistance against therapeutic drugs and is a major complication for achieving optimal therapy response. Deregulated expression of the MYCN gene is a critical determinant in neuroblastoma progression, and one of the pleiotropic functions of the MYCN protein is cellular sensitization to cytokine-induced and drug-induced apoptosis. By using the functional approach of technical knockout (TKO), we have identified five genes that regulate sensitization for IFN-gamma-induced cell death. Most efficient among them is the newly identified SOXN (neuroblastoma-derived sulfhydryl oxidase), which comprises 12 exons and maps to 9q34.3. SOXN encodes a putative protein of 698 amino acids that contains a signal sequence, a protein-disulfide-isomerase-type thioredoxin and a yeast ERV1 domain and is highly homologous to members of the sulfhydryl oxidase/Quiescin6 family. The SOXN protein is predominantly located in the plasma and in the nuclear membrane. Antisense SOXN confers resistance to IFN-gamma-induced apoptosis. In contrast, ectopic overexpression of sense-SOXN sensitizes the cells to induced cell death. These results identify SOXN as a major player in regulating the sensitization of neuroblastoma cells for IFN-gamma-induced apoptosis.