TSP50, a possible protease in human testes, is activated in breast cancer epithelial cells.
Initial studies have identified TSP50 as a human testes-specific gene that is demethylated in breast cancer. In this study, we will present new data related to the TSP50 gene. We have found that the TSP50 gene product shares a similar enzymatic structure with many serine proteases. However, the most critical catalytic site, serine, has been replaced by threonine. Western analysis revealed that in human testes, the TSP50 antibody detected two closely positioned protein bands whose estimated molecular masses were 37 kDa, whereas in a large portion of breast cancer tissues, but not normal control tissues, only one band was present. Immunohistochemistry assays found TSP50 proteins located in the spermatocytes of human testes, whereas in situ hybridization and immunohistochemistry confirmed that gene activation in breast tumors took place in malignant mammary epithelial cells. These results suggested that the normal function of the TSP50 gene was involved in spermatogenesis, whereas the up-regulation of TSP50 in many breast cancer patients not only indicated that it might be a novel biomarker for this disease but also encouraged us to further explore the possibility of whether it was an oncogene.
Shan
Jidong
J
Department of Molecular Oncology, North Shore-Long Island Jewish Research Institute, New York University School of Medicine, Manhasset, New York 11030, USA.
Yuan
Liming
L
Xiao
Qianxun
Q
Chiorazzi
Nicholas
N
Budman
Daniel
D
Teichberg
Saul
S
Xu
Hao-peng
HP
D000595:Amino Acid Sequence; D000906:Antibodies / Q000276:immunology / Q000302:isolation & purification; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics; D002846:Chromatography, Affinity; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000201:enzymology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D013090:Spermatocytes / Q000201:enzymology; D013737:Testis / Q000201:enzymology*
D000906:Antibodies; D012697:Serine Endopeptidases; C446379:testis-specific protease 50