Nucleostemin and ASPP2 expression is correlated with pituitary adenoma proliferation

Abstract

Nucleostemin is a GTP-conjugated protein located in the nucleoli of stem cells and certain cancer cells, and maintains cellular self-renewal. The present study aimed to evaluate nucleostemin as a potential target for pituitary adenoma gene therapy by investigating nucleostemin and apoptosis-stimulating of p53 protein 2 (ASPP2) expression and their effect on pituitary adenoma cell proliferation. A total of 71 samples of pituitary adenomas were collected. Semi-quantitative PCR was used to detect the expression of nucleostemin and ASPP2 mRNA in the samples. Immunochemistry techniques were used to examine Ki-67 expression in the paraffin section of the samples. Coherent clinical data were also collected. Nucleostemin and ASPP2 were detectable in all the pituitary adenoma samples. Significant differences were observed in nucleostemin and ASPP2 expression between invasive pituitary adenoma and non-invasive pituitary adenomas (P<0.01) and the Ki-67 labeling index (LI; P>0.05). The difference in the Ki-67 LI between the recurrence and non-recurrence groups was significant (P<0.05). There was positive correlation between nucleostemin gene expression and the Ki-67 LI levels (P<0.05). The correlation between ASPP2 expression and the Ki-67 LI was negative (P<0.05). Negative correlation was demonstrated between nucleostemin and ASPP2 expression (P<0.01). The nucleostemin and ASPP2 genes were expressed in the human pituitary adenoma tissues. The differences in the expression of nucleostemin, ASPP2 and Ki-67 in the various pathological types of pituitary adenomas represented differences in molecular biological character and were associated with invasion. In the pituitary adenomas, the expression of nucleostemin and ASPP2 was correlated with tumor proliferation. Nucleostemin, ASPP2 and Ki-67 may serve as valid clinical detection markers for the invasion of pituitary adenomas.