Black Maitake mushroom ( Grifola frondosa ) extract exerts anti-cancer effects and enhances the efficacy of chemotherapeutic drugs in 2D and 3D models of triple-negative breast cancer

Abstract Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that lacks hormone receptors and HER2 amplification, limiting targeted therapy options. Chemotherapeutics like cisplatin and taxol are commonly used but lack selectivity, often causing harsh side effects. These limitations have led to increased interest in natural health products (NHPs) as complementary treatments due to their potential anticancer benefits and lower toxicity. Black Maitake mushroom ( Grifola frondosa ), used in traditional Chinese medicine, contains polysaccharides with reported anticancer activity. However, further research is needed on the whole extract, its mechanism, and its interaction with chemotherapy. Objectives This study assessed the anticancer effects of Black Maitake Odaira Extract – Prothera (BMOE; manufactured by Shogun Maitake Canada, London, ON) on the MDA-MB-231 TNBC cell line. BMOE was evaluated alone and in combination with chemotherapeutic agents cisplatin and taxol using both 2D and 3D in vitro models. Methods Apoptosis was evaluated using Hoechst 33342, Annexin V, and propidium iodide staining. Mitochondrial membrane depolarization was assessed via TMRM. A wound-healing assay measured cell migration. Structural effects were examined in 3D spheroid cultures following treatment. Results BMOE induced dose- and time-dependent apoptosis and mitochondrial depolarization. In 3D models, BMOE disrupted spheroid structure. The wound-healing assay showed impaired TNBC cell migration. Most importantly, BMOE significantly enhanced chemotherapeutic efficacy when combined with cisplatin or taxol. Conclusions These findings highlight the potential of BMOE as a non-toxic adjunct that enhances the efficacy of standard chemotherapies to contribute to the development of safer, more targeted treatment strategies for TNBC.