Abstract: Objectives To discuss the effect of alter-expressed PER2 on proliferation, apoptosis and other clock genes expression in human oral squamous cell carcinoma SCC15 cells. Method Short hairpin RNA interference was used to knockdown PER2 effectively 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 obviously after PER2 knockdown in SCC15 cells (P<0.05). The mRNA expressions of PER3, BMAL1, DEC1, DEC2, CRY2, TIM, RORα and NPAS2 were significantly down-regulated, and the mRNA expressions of PER1 and REV-ERBα were 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.

Key words: cancer, oral ?cavity, clock gene, PER2