Characterization of the Monoclonal Antibody Specific to Human S100A2 Protein

BACKGROUND: The S100A2 gene, also known as S100L or CaN19, encodes a protein comprised of 99-amino acids, is a member of the calcium-binding proteins of EF-hand family. According to a recent study, this gene was over-expressed in several early and malignant carcinomas compared to normal tissues. To elucidate the role of S100A2 protein in the process during carcinogenesis, production of monoclonal antibody specific to the protein is essential. METHODS: First, cDNA sequence coding for ORF region of human S100A2 gene was amplified and cloned into an expression vector to produce GST fusion protein. Recombinant S100A2 protein and subsequently, monoclonal antibody to the protein were produced. The specificity of anti-S100A2 monoclonal antibody was confirmed by immunoblot analysis of cross reactivity to other recombinant proteins of S100A family (GST-S100A1, GST-S100A4 and GST-S100A6). To confirm the relation of S100A2 to cervical carcinogenesis, S100A2 protein in early cervical carcinoma tissue was immunostained using the monoclonal antibody. RESULTS: GST-S100A2 recombinant protein was purified by affinity chromatography and then fusion protein was cleaved and S100A2 protein was isolated. The monoclonal antibody (KK0723; Korean patent pending #2001-30294) to the protein was produced and the antibody did not react with other members of EF-hand family proteins such as S100A1, S100A4 and S100A6. CONCLUSION: These data suggest that anti-S100A2 monoclonal antibody produced in this study can be very useful for the early detection of cervical carcinoma and elucidation of mechanism during the early cervical carcinogenesis

Expression Patterns of S100A6 Gene in Human Thyroid Diseases

S100A6 (calcyclin) is a member of the S100 family and has been originally isolated from the cDNA library of Syrian baby hamster kidney cells. The S100A6 gene expression is reported to remain high throughout the cell cycle following induction by serum or growth factors, suggesting that the gene may be required for cell cycle progression. Nevertheless, the role that S100A6 may play in tumor progression remains unknown. In this study, we have explored the expression patterns of S100A6 gene in human thyroid tissues by northern blot analysis. Using the S100A6 monoclonal antibody, we carried out the immunohistochemical staining to determine the distribution/localization of S100A6 protein within tumor or non-tumorous cells of the thyroid. To modulate the regulation of endogenously expressed S100A6 protein in the intracellular level, overexpressed or anti-sense treated transfectant was constructed by using the eukaryotic expression vector. As a result, immunohistochemistry for S100A6 showed a strong positivity in the malignant tumors of thyroid and a high expression level of S100A6 protein affected cell proliferation in the overexpressed transfectant. These findings suggest that S100A6 may be involved in the tumor pathogenesis and provides another parameter for the differentiation of malignant and benign lesions. A well defined monoclonal antibody against S100A6 protein is now available for the immunohistochemical studies of the various thyroid tissues.