The cytotoxicity and apoptotic effects of verbascoside on breast cancer 4T1 cell line

Abstract Background Despite significant advancements in breast cancer therapy, novel drugs with lower side effects are still being demanded. In this regard, we investigated the anti-cancer features of verbascoside in 4 T1 mouse mammary tumor cell. Methods First, MTT assay was performed with various concentrations (ranging between 5 to 200 μM) of verbascoside and IC50 was calculated. Then the expression of Bax, Bcl-2, and caspase-3 was evaluated in treated 4 T1 cells. In addition, we investigated the expression of TLR4, MyD88, and NF-κB to ascertain the underlying mechanism of the anti-proliferative feature of verbascoside. Also, flow cytometry followed by double PI and Annexin V was conducted to confirm the apoptosis-inducing effect of verbascoside. Results Our results from MTT assay showed verbascoside inhibits proliferation of 4 T1 cancer cells (IC50 117 μM) while is safe for normal HEK293T cells. By qRT-PCR, we observed that verbascoside treatment (100, 117 and, 130 μM) increases the expression of caspase-3 and Bax while reduces the expression of Bcl-2. Also, verbascoside (100, 117 and, 130 μM) increased the expression of TLR4 only at 130 μM dose and the expression of MyD88 whereas reduced the expression of NF-κB at mRNA level. Flow cytometry analysis also confirmed verbascoside induces apoptosis in 4 T1 cells at 117 μM. Conclusion Taken together, our data showed verbascoside is a safe natural compound for normal cells while has apoptosis-inducing feature through TLR4 axis on 4 T1 cells.