The Influence Of Circadian Clock Gene Bmal1 In Oral Squamous Cell Carcinomas

This oral cancer is any cancerous tissue growth located in the oral cavity and its adjacent anatomic structure,accounting for about 2%~3 %in whole body malignant tumor. Its has a substantial mo Rbidity with 4.7 ~ 32.2/105, about 90% of these were OSCC.Although the treatments such as surgery, chemotherapy and radiotherapy have made certain progress, but overall survival in patients with 5 years is still only 50% ~ 60%. Then providing a scientific basis for early diagnosis and prognosis is very important.Physiological processes such as the sleep-wake cycle, metabolism and hormone secretion are controlled by a circadian rhythm adapted to 24 h day-night Periodicity.Disruption of circadian rhythm can lead to cancer,while study found that some Clock related gene expression abnormal in some tumor cells.As a important part of circadian Clock system,Bmal1 plays an important role in maintaining circadian rhythm.Research suggests that Bmal1 closely linked with the development of tumor,it is found that Bmal1 play an important role in the development and prognosis of colon cancer, breast cancer, lymphoma, etc.There is no study about the relationship between Bmal1 and oral squamous cell carcinomas.This ex Periment building Bmal1 overexpression vector,transfecting the oral squamous cancer cells SCC- 15,then observe its effect on the growth of the squamous cancer cells, as well as the impact on the Clock related factors, providing new ideas and thoughts for the therapy of OSCC.Objective Constructing Bmal1 overexpression vector,transfecting the SCC- 15,then observe its effect on the growth of the squamous cancer cells, as well as the impact on the Clock related factors, providing new ideas and thoughts for the therapy of oral squamous cell carcinomas.Methods(1) Cultivating oral squamous cancer cells SCC- 15,CAL- 27 and normal control group Ha Cat cells, detecting the expression of Bmal1 by q RT-PCR and Western methods;(2)Constructing Bmal1 overexpression vector, transfect the oral squamous cancer cells SCC-15.Set the SCC-15 / vector empty vector control and SCC- 15 / Lv- Bmal1 ex Perimental group, testing each growth rate by CCK-8 detection, colony forming ex Periment;(3)Detecting its cell cycle and apoptosistrain processing flow cytometry instrument;(4) Detecting the expression of P53,Bax, Rb, cyclin B1 and CDC2 by q RT-PCR.Results(1) Bmal1 was significantly decreased in SCC-15 and CAL-27 compared with Ha Cat cells,especially SCC-15 cells(p<0.01);(2) Bmal1 stably overexpressed SCC-15 cells were constructed successfully,It was illustrated by CCK-8 assays that the cell proliferation in SCC-15/Lv-Bmal1 group was significantly inhibited compared with and SCC-15/Vector groups after 72 hours(P<0.05).The results were also confirmed by colony formation assays, which showed a decrease of about 50% in the number of cell colonies in the SCC-15/Lv-Bmal1 group compared with other groups(P<0.01);(3)SCC-15/Lv-Bmal1 group showed a cell-cycle arrest at the G1/S checkpoint, with an accumulation of cells in G1/G0 phase(p<0.05) and a decrease in S phase(p<0.05) and G2/M phase(p<0.01) cells compared with SCC-15/Vector group,Apoptosis assays illustrated that the percentage of apoptotic cells was higher in SCC-15/Lv-Bmal1 group compared with SCC-15/Vector group(20.91±3.13% vs. 6.92±1.15%).Conclusions In oral squamous cancer cells, the expression of Bmal1 stay a low level, Bmal1 can inhibit the growth of the SCC-15 cells, promote cell apoptosis, In sum, the findings suggest that Bmal1 acts as an antioncogene in SCC-15 cells and may be a novel therapeutic target for OSCC treatment.