Expression of p120 nucleolar proliferating antigen in human gliomas and growth suppression of glioma cells by p120 ribozyme vector

p120 is a nucleolar proliferating antigen which is expressed in tumor cells but not normal resting cells. The expression and localization of p120 in human gliomas were studied by Northern blot analysis, Western blot analysis and immunohistochemistry. All five of the glioma cell lines and all of the glioma specimens we investigated expressed p120 at both the mRNA and protein levels. p120 expression was not detected in adjacent brain tissues. A ribozyme vector was constructed to cleave the first GUC sequence in the coding region of p120 mRNA. This p120 ribozyme vector was transfected into the glioma cell line SF188, which expresses p120. The reduced p120 expression of the transfectant at both the mRNA and protein levels was confirmed. An MTT assay indicated that the transfected cells grew more slowly than control cells. These results indicate that i) p120 has an important role in the proliferation of gliomas, and ii) the ribozyme against p120 mRNA can suppress glioma cell growth.