Cucurbitacin B suppresses metastasis mediated by reactive oxygen species (ROS) via focal adhesion kinase (FAK) in breast cancer MDA-MB-231 cells

摘要

Metastasis is responsible for the majority of cancer-related deaths and prevention of metastasis remains a big challenge for cancer therapy.Cucurbitacin B (Cuc B) is a natural triterpenoid with potent anticancer activities while its effect on metastasis remains unclear.In the present study,the inhibitory effect and mechanisms of Cuc B on metastasis were investigated in MDA-MB-231 breast cancer cells.The cells were treated with or without Cuc B,and the cytotoxicity was determined by MTT assay.The effect of Cuc B on metastasis was evaluated with wound healing,transwell,and adhesion assays.Furthermore,the adhesion of cancer cells to endothelial cells was determined.The protein expression was determined by Western blotting.Cuc B (＜ 100 nmol·L-1) showed no obvious cytotoxicity to MDA-MB-231 cells,but significantly inhibited migration,invasion,and adhesion to Matrigel,fibronectin,type Ⅰ collagen,and endothelial cells.Cuc B dramatically inhibited the phosphorylation of focal adhesion kinase (FAK) and paxillin in dose-and time-dependent manners.Furthermore,Cuc B induced intracellular reactive oxygen species (ROS) generation,which could be reduced by N-acetyl-l-cysteine (NAC).In addition,NAC pretreatment could reverse Cuc B-induced suppression of migration and adhesion,expression of FAK,but showed no effect on paxillin expression.In summary,Cuc B suppressed ROS-dependent metastasis through FAK pathway in breast cancer MDA-MB-231 cells,demonstrating novel mechanisms for the anticancer effects of Cuc B.