F1012-2 Induced ROS-Mediated DNA Damage Response through Activation of MAPK Pathway in Triple-Negative Breast Cancer

We have previously reported that F1012-2, a sesquiterpene lactone isolated from the Chinese herbal medicine Eupatorium lindleyanum DC., exhibits strong effects against Triple Negative Breast Cancer (TNBC). In this study, we found F1012-2 effectively inhibited cell migration and invasion detected by wound healing and transwell assays. In order to elucidate the potential mechanisms of F1012-2, we further studied its effect on DNA damage in TNBC cell lines. Using single cell gel electrophoresis (comet assay), immunofluorescence, and western blotting assays, we found that F1012-2 treatment induced significant DNA strand breaks and γ-H2AX activation. Moreover, exposure to F1012-2 led to overproduction of reactive oxygen species (ROS). NAC treatment completely eliminated ROS, which may be due to the interaction between NAC and F1012-2. A further study of the molecular mechanisms demonstrated that the MAPK signaling pathway participated in the anti-TNBC effect of F1012-2. Pretreatment with specific inhibitors targeting JNK (SP600125) and ERK (PD98059) could rescue the decrease in cell viability and inhibit expressions of JNK and ERK phosphorylation, but SB203580 had no effects. Finally, in the acute toxicity experiment, there were no obvious symptoms of poisoning in the F1012-2 treatment group. An in vivo study demonstrated that F1012-2 significantly suppressed the tumor growth and induced DNA damage. In conclusion, the activity of F1012-2-induced DNA damage in TNBC was found in vivo and in vitro, which might trigger the MAPK pathway through ROS accumulation. These results indicate that F1012-2 may be an effective anti-TNBC therapeutic agent.