Objective: To assess the effect of small interfering RNA (siRNA)-mediated gene silencing of DJ-1 on the proliferation of human laryngeal carcinoma cell line Hep-2.
Methods: Three siRNA sequences specific to DJ-1 gene were synthesized according to GenBank. Human laryngeal carcinoma cell line Hep-2 was cultured and divided into 4 groups: non-specific group (siRNA control) and 3 RNAi groups, transfected with specific DJ-1 siRNA (siRNA1, siRNA2, siRNA3). The mRNA and protein levels of DJ-1 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western Blot respectively. Cell apoptosis were analyzed by flow cytometry. The proliferation of Hep-2 cells was assessed by MTT assay.
Results: DJ-1 siRNA down-regulated the mRNA and protein levels of DJ-1 in Hep-2 cells. After transfection, the expression of DJ-1 mRNA and protein levels in Hep-2 cells of the DJ-1 siRNA1 group were significantly lower than those of non-specific siRNA control group. MTT assay showed that DJ-1 siRNA1 group inhibited proliferation of Hep-2 cells. Flow cytometry showed that apoptosis rate of the DJ-1 siRNA1 group (15.7%) was significantly higher than that of non-specific siRNA control group (4.5%) or untransfected group (3.5%), t = 4.736, P < 0.01.
Conclusions: Specific siRNA targeting DJ-1 can effectively inhibit DJ-1 expression, resulting in the reduced proliferation and the enhanced apoptosis in Hep-2 cells.