Objective To find the effect of alter-expressed PER2 on proliferation,apoptosis and other clock genes expression in human oral squamous cell carcinoma SCC15 cells.Methods Short hairpin RNA interference was used to knockdown PER2 in SCC15 human oral squamous cell carcinoma cells.Flow cytometry analysis was used to testify the cell proliferation and apoptosis.Quantitative real-time PCR was used to testify the mRNA expressions of PER3,BMAL1,DEC1,DEC2,CRY2,TIM,RORα,NPAS2,PER1 and REV-ERBα.Results The proliferation was enhanced and apoptosis was decreased after PER2 knockdown in SCC15 cells (P<0.05).The mRNA expression of PER3,BMAL1,DEC1,DEC2,CRY2,TIM,RORα and NPAS2 was significantly down-regulated,and the mRNA expression of PER1 and REV-ERBα was significantly up-regulated (P<0.05).Conclusions Clock gene PER2 plays an important role in regulating other clock genes of the clock gene network in cancer cells,PER2 knockdown can enhance proliferation and recede apoptosis of cancer cell.

OBJECTIVEThis study investigated the effect of clock gene PER1 on the expression levels of other clock genes in clock gene networks in oral squamous cell carcinoma cells.

METHODSWe used RNA interference mediated by short hairpin RNAs (shRNAs) to effectively knock down PER1 in SCC15 human oral squamous cell carcinoma cells. Flow cytometry was used to detect the degree of proliferation and apoptosis of the cells after PER1 knockdown, and quantitative real-time PCR was used to detect the mRNA expression levels of the clock genes CLOCK, BMAL1, PER1, PER2, PER3, DEC1, DEC2, CRY1, CRY2, TIM, CKIE, RORA, NPAS2, and REV-ERBA.

RESULTSThe proliferation index of SCC15 cells increased significantly while the apoptotic index decreased significantly after PER1 knockdown (P<0.05). The mRNA expression levels of PER1, PER2, DEC1, DEC2, CRY1, CRY2, and NPAS2 markedly decreased (P<0.05) while those of PER3, TIM, RORA, and REV-ERBA markedly increased (P<0.05). By contrast, no obvious changes were observed in the mRNA expression levels of CLOCK, BMAL1, and CKIE (P>0.05).

CONCLUSIONSThe clock gene PER1 can regulate the expression levels of other clock genes in the clock gene networks; these genes include PER2, DEC1, DEC2, CRY1, CRY2, NPAS2, PER3, TIM, RORA, and REV-ERBA. PER1 gene thus plays an important role in the regulation of clock gene networks.
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Apoptosis ; Carcinoma, Squamous Cell ; Gene Regulatory Networks ; Head and Neck Neoplasms ; Humans ; Mouth Neoplasms ; RNA Interference ; RNA, Small Interfering ; Real-Time Polymerase Chain Reaction