[Effects of geranylgeranyltransferaseâ silencing on the proliferation of tongue squamous cancer cells].

Objective This study aims to investigate the effect of geranylgeranyltransferaseⅠ (GGTase-Ⅰ) on the proliferation and growth of tongue squamous cancer cells. Methods Three small interfering RNAs (siRNAs) were designed on the basis of the GGTase-Ⅰ sequence in GeneBank. These siRNAs were then transfected into tongue squamous cancer cells Cal-27. The mRNA and protein expression of GGTase-Ⅰ and RhoA were examined by real-time quantitative polymerase chain reaction and Western blotting, respectively. The expression of Cyclin D1 and p21 were examined by Western blotting. The proliferation and growth ability were analyzed by cell counting kit-8 assay and flow cytometry. Results The mRNA and protein expression of GGTase-Ⅰ in Cal-27 was reduced significantly after the GGTase-Ⅰ siRNAs were transfected (P<0.05). No significant difference in RhoA mRNA and protein expression was detected (P>0.05). Cyclin D1 expression decreased, whereas p21 expression increased significantly. The cell cycle was altered, and the growth-proliferative activity was inhibited (P<0.05). Conclusion GGTase-Ⅰ siRNA can inhibit the expression of GGTase-Ⅰ and the proliferative activity of tongue squamous cancer cells. GGTase-Ⅰ may be a potential target for gene therapy in tongue squamous cell cancer.

[Effects of RhoA silencing on proliferation of tongue squamous cancer cells].

OBJECTIVE: This study investigated the effect of RhoA silencing through RNA interference on proliferation and growth of tongue cancer cells, as well as explored the possible mechanisms of this effect. METHODS: SSC-4 tongue cancer cells were cultured in vitro and then transfected with small interfering RNA to knock down RhoA expression. The tested cells were divided into three groups: experimental group (experimental group 1: transfected with RhoA-siRNA-1; experi-mental group 2: transfected with RhoA-siRNA-2), negative control group (transfected by random sequence NC-siRNA), and blank control group (transfected with Lipofectamine). The expression levels of RhoA mRNA were respectively measured by quantitative real-time polymerase chain reaction and western blot assay. Moreover, the expression levels of cyclin D1, p21, and p27 and RhoA protein were evaluated by Western blot assay. Proliferation and growth potentiality were analyzed through evaluation of doubling times and methyl thiazolyl tetrazolium assessment. RESULTS: The expression levels of RhoA gene and protein of experimental groups significantly decreased following siRNA transfection compared with those in the negative and blank control groups. The expression of cyclin D1 decreased significantly and that of p21 and p27 increased significantly. The doubling time was extended and the growth potentiality decreased. CONCLUSIONS: The results indicated that RhoA silencing can inhibit proliferation of tongue cancer cells, whereas RhoA affects cell proliferation by regulating the cell cycle pathway. Thus, RhoA is a potential target in gene therapy for tongue cancer.