Down-regulation of cyclin D1 by small interfering RNA inhibits cell growth and induces apoptosis of laryngeal squamous cell carcinoma

Abstract

Objective The objective of the study was to explore the inhibitive role of cyclin D1 gene silence in laryngeal squamous cell carcinoma by lentivirus-mediated RNA interference. Materials and Methods Cd1-RNAi-Lentivirus and the control lentivirus (GFP-Lentivirus) were transfected into Hep-2 cells. Reverse transcriptase polymerase chain reaction was performed to explore the cyclin D1 expression level in Cd1-RNAi-Lentivirus–transfected Hep 2 cells. The apoptosis and viability of Cd1-RNAi-Lentivirus–treated Hep-2 cells were measured with flow cytometry and methyl thiazolyl tetrazoliym assay. In an animal experiment, 10 mice bearing Hep-2 cell tumor were intratumorally injected with Cd1-RNAi-Lentivirus; and the other 10 mice were injected with GFP-Lentivirus. Terminal deoxytransferase–mediated dUTP nick end labeling stains and transmission electron microscope were used to observe the apoptosis in the xenografts. Results Cyclin D1 was knocked down after Cd1-RNAi-Lentivirus was transfected into Hep-2 cells. The proliferative ability of Hep-2 cells was significantly inhibited by Cd1-RNAi-Lentivirus, and a significant apoptosis of Hep-2 cells was also observed after Cd1-RNAi-Lentivirus transfection. The average weight and volume of tumors in the Cd1-RNAi-Lentivirus–treated group were significantly lower than those in the control group ( P < .01). The significant apoptosis was detected with terminal deoxytransferase–mediated dUTP nick end labeling stain and transmission electron microscope. Conclusions The present findings suggest that cyclin D1 gene silence by lentivirus-mediated RNA interference can inhibit growth and promote apoptosis of laryngeal squamous cell carcinoma.