Expression Of Aurora A In Human Gliomas And The Effect Of Aurora A Gene On Proliferation And Apoptosis In Glioma Cells

Objective:The purpose of this study was to investigate the expression level of Aurora A in different grade of gliomas, and to study the inhibitory effect of RNA interference on the expression of Aurora A in U251 cells, and the influence on proliferation and apoptosis of U251 cells, as well as the influence on chemotherapy sensitivity of U251 cells.Methods:The expression of Aurora A gene and PCNA was determined by immunohistochemistry method in 80 cases of gliomas and 10 cases of normal brain tissues. The siRNA Specific for Aurora A was synthesized and transfected into U251 cells. Aurora A mRNA expression and protein content were detected by RT-PCR and Western blot respectively. The cell proliferation and apoptosis were observed by MTT and FCM. Transmission electron microscope was used to observe the ultrastructural changes of U251 cells. Under the action of chemotherapy drug Nimustine, the changes in proliferation and apoptosis of U251 cells before and after the transfection of Aurora A siRNA were studied by MTT and FCM as well.Results:The positive rate of Aurora A expression was 57.5%(46/80) in the gliomas, and the positive rate of PCNA was 65.0%(52/80). There was no expression of Aurora A or PCNA in all the normal brain tissues. The expression levels of Aurora A and PCNA in high grade gliomas were significantly higher than low grade group(P<0.01). The expressions of Aurora A have positive correlation with the expression of PCNA protein (P<0.01). After transfection, the expression level of Aurora A mRNA was significantly decreased(P<0.01), and the protein content of Aurora A was also obviously reduced. The inhibitory rate of cell proliferation reach up to 67.57% 72 hours after transfection, which was significantly higer than normal control group(P<0.01). The apoptosis rate of U251 cells was significantly increased from 3.69±0.87% to 15.34±2.16% (P＜0.01). Under the transmission electron microscope, it was observed that the U251 cells showed typical morphologic changes of apoptosis after transfection, such as karyopyknosis, chromatin condensation and margination, intracytoplasmic vacuoles formed, and apoptotic bodies formed. The inhibitory rate of U251 cells after transfected with Aurora A siRNA was enhanced significantly by Nimustine, which reach up to 74.32%. While under the action of Nimustine, the apoptosis rate of U251 cells after transfection was also significantly increased, the apoptosis rate was (20.16±1.75)%.Conclusion:Aurora A was expressed in glioma tissues and the expressing intensity inereased when the glioma grade went up. The expression of Aurora A was more intensive in grade 111 and grade IV gliomas than in normal brain tissues, gradeⅠand gradeⅡgliomas, which indicated maybe Aurora A was related to the genesis and progression of gliomas. Aurora A should be considered as the indicators of the biological behavior in glioma. The expression of Aurora A gene can be inhibited by siRNA successfully, and it results in the suppression of cell growth, induce apoptosis of human glioma cells and improve the chemosensitivity of glioma cells in vitro. Aurora A may become a new target for the gene therapy of gliomas.