Bi-directional solid fermentation products of Trametes robiniophila Murr with Radix Isatidis inhibit proliferation and metastasis of breast cancer cells

Background: The bi-directional solid fermentation product extract of Trametes robiniophila Murr (Huaier) with Radix Isatidis (TIF) has been shown to have good anti-tumor activity. However, the mechanisms of this activity are still unknown. In the present study, we aimed to investigate its inhibitory effect on both SK-BR-3 and MDA-MB-231 cells, and explore the possible mechanisms of its anti-cancer effect in vitro. Methods: The experiment comprised a control group, Radix Isatidis group, Huaier group, and TIF group. The cell viability was measured by MTT and the distribution of cell cycle and apoptosis levels were analyzed by flow cytometry. Cell scratch, Transwell, and adhesion assays were used to measure the effects of the test compounds on the migration, invasion, and adhesion capability of SK-BR-3 and MDA-MB-231 cells. The effects of TIF on the mRNA and protein expression related to apoptosis and migration were measured by using semi-quantitative RT-PCR and western blotting. Results: TIF strongly inhibited the cell proliferation of the SK-BR-3 and MDA-MB-231 cells in a time-dependent manner and induced G2/M arrest and apoptosis. Furthermore, TIF significantly inhibited the proliferation, migration, invasion, and adhesion capabilities of SK-BR-3 and MDA-MB-231 cells. Compared with other treatments, the anticancer effect of TIF were stronger in MDA-MB-231 cells. Semi-quantitative RT-PCR suggested that TIF may upregulate the expression of p53 and caspase-3 to inhibit cell proliferation, and downregulate the expression of MMP-9/Snail and MMP-9/MMP-2 to inhibit the migration, invasion, and adhesion capabilities of SK-BR-3 and MDA-MB-231 cells. Western blotting results showed that TIF increased the expression of p53 protein and decreased the expression of MMP-9 protein in SK-BR-3 and MDA-MB-231 cells. Conclusion: The results indicated that the bi-directional solid fermentation may enhance the efficacy of Huaier in MDA-MB-231 cells and that TIF may be an effective complementary medicine for cancer treatment. Keywords: Apoptosis, Breast cancer, Fermentation, Huaie