Abstract: Objective To investigate 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. Methods The siRNA specific for Aurora A was synthesized and transfected into U251 cells EM>in vitro/EM>. Aurora A mRNA expression and protein content were detected by RT-PCR and Western blotting respectively. The cell proliferation and apoptosis were observed by methyl thiazolyl tetrazolium(MTT) and flow cytometry(FCM). Transmission electron microscope was used to observe the ultrastructural changes of U251 cells. Results After transfection, the expression level of Aurora A mRNA was significantly decreased(EM>P/EM><0.01), and the protein content of Aurora A was also obviously reduced. The inhibitory rate of cell proliferation reached up to 67.57% 72 hours after transfection, which was significantly higer than that of normal control group(EM>P/EM><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. Conclusion The expression of Aurora A gene can be inhibited by siRNA successfully, and it results in the suppression of cell growth and induce apoptosis of human glioma cells EM>in vitro/EM>. Aurora A may become a new target fo

Key words: RNA interference, Aurora A, Glioma, U251 cell, Methyl thiazolyl tetrazolium, Flow cytometry, Human