Gli1, cyclin D1, Bcl-2 and Bax mRNA levels in blank, Lipofectamine, siRNA-Gli1, BCNU and combination groups. Semi-quantitative real-time polymerase chain reaction was performed using SuperScript III One-Step RT-PCR kit (12574-018, Invitrogen, Thermo Scientific, Waltham, MA, USA) on PCR thermo cycler (C1000, Bio-Rad, Hercules, CA, USA). The 20 μl reaction system was formed by cDNA (5 μl), 10× buffer (2 μl), 25 mmol/L MgCl 2 (0.8 μl), 2.5 mmol/L dNTP (2 μl), DNA polymerase (0.2 μl; Takara, Tokyo, Japan), and upstream and downstream primers (1 μl each). M, markers; 1, blank group; 2, Lipofectamine group; 3, BCNU group; 4, siRNA-Gli1 group; 5, combination group.