The comet assay was performed as previously described.30 Briefly, molten 0.6% N-methyl-1,3-propanediamine was used to soak the frosted glass slide, which was left to dry naturally. Then, 70 μL of 0.7% LMPA at (37°C) was added to 10 μL of 4T1 cell suspension from each group to reach a cell number of 6,000. The solution was mixed and rapidly dripped on the frosted glass slide preheated at 37°C, immediately covered with a coverslip, and fixed at 4°C for 10 min. Subsequently, the coverslip was removed, and the cells were lysed in pre-cooled cell lysate at 4°C for 1 h in the dark. Electrophoresis was performed after unwinding for 30 min in alkaline electrophoresis buffer (electrophoresis parameters: 25 V, 300 mA, 25 min). After electrophoresis, the slides were rinsed and 20 ug/mL of EB 10 μL was added dropwise. The slides were covered with a coverslip and observed under a fluorescence microscope (DP80; Olympus). The extent of DNA damage was analyzed using the CASP software and evaluated as the percentage of DNA in the tail of the comet (Tail DNA%).