Hydroalcoholic extract of Taraxacum officinale induces apoptosis and autophagy in 4T1 breast cancer cells

Triple-negative breast cancer (TNBC) is an aggressive and deadly breast cancer sub-type with limited therapeutic options. Dandelion (Taraxacum officinale) exhibiting extensive anti-cancer activity is reported to be effective against TNBC; however, its anti-tumor effect mechanisms have not been fully elucidated. The purpose of this study was to determine the anti-cancer activity of hydroalcoholic extract of dandelion (HADE) on 4T1 cells, and the mechanism of HADE-induced cell death. The effect of HADE on cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays. Apoptotic cell death was monitored by flow cytometry. The DNA fragmentation was evaluated by Acridine orange/Ethidium bromide (AO/EB) staining. Nitric oxide (NO) level was detected using Griess assay. The effects of HADE on Atg-7, Beclin-1, Bcl2, Bax and p53 genes were investigated by real-time reverse transcription-polymerase chain reaction. The results showed that HADE inhibited cell growth and proliferation in a dose- and time-dependent manner. The HADE induced 4T1 breast cancer cell death via apoptosis and autophagy. The DNA fragmentation was improved as the concentration of HADE increased. The NO secretion was declined with increasing concentration of HADE. Gene expression analysis confirmed HADE-induced apoptosis and autophagy in cancer cells. The Bax, Bax/Bcl-2 ratio, p53, Beclin-1 and Atg-7 over-expression as well as Bcl-2 down-regulation were also evident in treated cancer cells.