Mechanisms Of Red Cabbage Anthocyanin Inhibits Triple-negative Breast Cancer And Melanoma

Anthocyanins, a group of molecules called flavonoids, is a kind of water-soluble natural pigment in plants and widely distribute in the vegetables. They had be reported to inhibit the growth and metastatic of cancer cells. We test the total anthocyanins content in common vegetables, and found red cabbage anthocyanin has the highest anthocyanins. And the content of anthocyanin is also different in different parts of the purple cabbage. But anthocyanin is a mixture and the main anthocyanin in red cabbage extract is cyanidin-3-o-glucoside (Cy-3-glu). So, we will research a broad spectrum of the single component:Cy-3-glu and red cabbage extract on triple negative breast cancer (TNBC) and mouse melanoma as the main topic. TNBC is one of several clinical subtypes of breast cancer defined by a lack of expression of estrogen receptors (ER), progesterone receptors (PR), and the HER-2/neu epidermal growth factor receptors and accounts for 10-15% of all breast cancer. TNBC has a large risk of distant metastases and poor prognostic. Melanoma is a skin cancer that originates in melanocytes. The two cancers are all lack of targeting therapy at present.We investigated the influence on the effect of extraction conditions for anthocyanins by single factor experiment. And selected some common vegetables to measure its total anthocyanin content by pH-differential method, and found that the content of anthocyanin is closely related to the color of vegetables:purple vegetables anthocyanin content is higher than red vegetables. And red vegetable is higher than yellow anthocyanin content. Red cabbage is the highest purple vegetables in anthocyanins content. And even if a red cabbage has the different content of anthocyanin within the different part: outside-in showed a trend of decline.Cy-3-glu as the main anthocyanin in red cabbage preferentially promoted the apoptotic cell death of triple-negative breast cancer (TNBC) cells, which co-express the estrogen receptor alpha 36 (ERa36) and the epidermal growth factor receptor (EGFR), such as MDA-MB-231, MDA-MB-436 and BT20 cells, but no apoptotic effects on MCF-7, SK-BR-3, and the normal breast epithelial cells MCF-10A. Mechanistically, we demonstrated that Cy-3-glu binds to the ligand-binding domain (LBD) of ER?36 directly and then leads to inhibit its downstream EGFR/AKT signaling and promote EGFR degradation through the proteasomes systems. This induces the expression of the tumor necrosis factor alpha (TNF-a) and cleaved-caspase-8/3 in TNBC cells without affecting cell-cycle and mitochondrial reactive oxygen species (ROS). We also confirmed the therapeutic efficacy of Cy-3-glu on TNBC with red cabbage extract and xenograft mouse model. And found red cabbage extract also could inhibit tumor cell growth. Moreover, we demonstrated that ERa36 (75.00%) and EGFR (68.75%) showed higher occurrences and were correlated (r= 0.536) in TNBC patients.We also found that Cy-3-glu also promoted the apoptosis of B16-F10 cells. We demonstrated that Cy-3-glu arrest cell cycle at G2/M phage by targeting recombinase RAD51 in B16-F10 cells. We also confirmed the therapeutic efficacy of Cy-3-glu on tumor mouse model with red cabbage extract. And found red cabbage extract also could inhibit tumor cell growth.In summary, our data revealed that some vegetables and fruits like red cabbage, which is rich of Cy-3-glu could be developed into a novel preventive and even therapeutic agent for a subtype of TNBC that co-expresses ER?36 and EGFR and also melanoma.