Black maitake induces apoptosis and enhances the efficacy of standard chemotherapy in 2D and 3D U-87 MG glioblastoma cell models

Abstract Objectives Glioblastoma is an aggressive primary brain tumor marked by rapid growth, invasiveness, poor prognosis, and an over 90 % tumor recurrence rate. Current radiation and chemotherapy treatments are limited by non-selectivity and toxicity, creating a need for safer complementary treatments. Historically, natural health products (NHPs) have been used medicinally across cultures for their anti-inflammatory and antioxidant effects. More recently, they have gained recognition for their selective, non-toxic properties in cancer treatment, suggesting their potential as adjuncts to conventional therapies. Black maitake ( Grifola frondosa ) extract, a well-tolerated NHP with known immunomodulatory properties, has demonstrated anticancer effects in breast cancer models. This study investigates the ability of Black Maitake Odaira Extract – Prothera (BMOE; a trade name of the extract manufactured by Shogun Maitake Canada, London, ON) to induce cell death in the U-87 MG glioblastoma cell line using 2D and 3D models, alone and in combination with the standard chemotherapy: temozolomide (TMZ). Methods Apoptosis was assessed via Hoechst 33,342, annexin V, and propidium iodide staining, along with morphological analyses. Mitochondrial depolarization was measured using TMRM, cell migration was assessed via wound-healing assays, and structural integrity was evaluated using 3D spheroids. Results BMOE, alone and with TMZ, induced dose-dependent apoptosis, mitochondrial depolarization, and impaired glioblastoma cell migration. BMOE also disrupted 3D spheroid structures and promoted nuclear condensation, consistent with apoptotic processes. Most notably, BMOE significantly enhanced the anti-cancer effects of TMZ. Conclusions These findings support the potential of BMOE as a complementary therapy that enhances the efficacy of current glioblastoma treatments.