Engineered Mesenchymal Stem Cells Expressing CD::UPRT and TRAIL Exhibit Potent Anti-Tumor Effects in Glioblastoma Patient-Derived Organoids.

Glioblastoma (GBM) is a highly aggressive brain tumor with limited therapeutic options due to its invasive nature, therapeutic resistance, and the challenge of drug delivery across the blood-brain barrier (BBB). Mesenchymal stem cells (MSCs), owing to their tumor tropic properties and ability to cross the BBB, offer a promising platform for targeted anti-cancer delivery. We previously engineered MSCs to express CD::UPRT and TRAIL, along with chemokine receptors to enhance tumor homing (MSC-CD-TRAIL; BM03). This study evaluated the anti-tumor efficacy of BM03 using GBM patient-derived organoids (GBOs), clinically relevant in vitro models. Using a GBO-MSC co-culture system, BM03 significantly increased cell death and reduced viability in GBOs from four GBM patients compared with controls and MSC-WT groups. In 3D invasion assays, BM03-treated GBOs showed markedly reduced invasive outgrowth, accompanied by downregulation of EMT markers (Zeb1 and Snail) and stem-like markers (Olig2 and Sox2), particularly in invasive regions. GFAP expression remained unchanged, suggesting selective targeting of tumor stem-like cells. Live-cell imaging further demonstrated BM03 infiltration into GBOs, which was associated with increased apoptosis, as evidenced by elevated cleaved caspase-3 levels. These findings provide organoid-based preclinical evidence supporting further evaluation of BM03 as an MSC-based therapeutic strategy for GBM.