Abstract:

Objective To discuss the effect of baicalin on the proliferation of the human tongue squamous cell carcinoma （tongue squamous cell carcinoma） CAL27 cells， and to clarify its potential mechanism. Methods The CAL27 cells at logarithmic growth phase were divided into control group and different concentrations （12.5， 25.0， 50.0， 100.0， and 200.0 μmol·L^－1） of baicalein groups， the clone formation of cells in various groups was observed by crystal violet staining； the proliferation rates of cells in various groups were detected by CCK-8 method；the levels of reactive oxygen species （ROS） in cells in vaious groups were detected by 2'， 7'-dichlorofluorescein diacetate （DCFH-DA） fluorescence probe； the mitochondrial membrane potential （MMP） of cells in various groups were detected by Rhodamine 123 fluorescence probe. The CAL27 cells at logarithmic growth phase were divided into control group and different concentrations （50， 100， and 200 μmol·L^－1） of baicalin groups. Flow cytometry was used to detect the percentages of the cells at different cell cycles and the apoptotic rates of cells in various groups. The CAL27 cells at logarithmic growth phase were divided into control group and different concentrations （50 and 100 μmol·L^－1） of baicalein groups， N-neneneba acetylcysteine （NAC） group， 50 μmol·L^－1 baicalin+NAC group，and 100 μmol·L^－1 baicalin+NAC group. The levels of ROS and MMP of cells in vraious groups were detected by DCFH-DA fluorescence probe and Rhodamine 123 fluorescence probe. Results The crystal violet staining results showed that compared with control group， the numbers of clone formation of the cells in different concentrations of baicalin groups were decreased in a concentration-dependent manner， and there was almost no clone formation of the cells in 200 μmol·L^－1 baicalin group.The CCK-8 assay results showed that compared with control group， the proliferation rates of the cells in different concentrations of baicalin groups were significantly decreased in a concentration-dependent manner（P<0.05 or P<0.01）. Compared with control group， the ROS levels of the cells in different concentrations of baicalin groups were significantly increased（P<0.05） and the MMP levels were significantly decreased （P<0.05）. Compared with control group， the percentages of the cells at S phase in different concentrations of baicalin groups were significantly increased（P<0.05）， the percentages of the cells at G₀/G₁ phase were significantly decreased （P<0.05）， and the apoptotic rates were significantly increased （P<0.05）. After the combination of baicalein and NAC， compared with control group，the ROS levels of the cells in 50 and 100 μmol·L^－1 baicalein groups were significantly increased （P<0.05） and the MMP levels were significantly decreased （P<0.05）；compared with 50 and 100 μmol·L^－1 baicalein groups， the ROS levels of the cells in 50 μmol·L^－1 baicalein+NAC group and 100 μmol·L^－1 baicalein+NAC group were significantly decreased （P<0.05），and the MMP levels were significantly increased （P<0.05）. Conclusion Baicalein can inhibit the proliferation of the CAL27 cells by activating the mitochondrial oxidative stress pathway.

Key words: Baicalien, Oral squamous cell carcinoma, Cell cycle, Reactive oxygen species, Mitochondrial membrane potential