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

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.