Novel therapy for gastric cancer peritoneal dissemination using genetically modified dental pulp cells and astatine-211

Peritoneal dissemination of gastric cancer is a terminal stage with limited treatment options and a five-year survival rate below 10%. To develop a more effective treatment, we created a new approach that uses genetically engineered human dental pulp cells (DPCs) that express the sodium/iodide symporter (NIS). These cells (NIS-DPCs) deliver astatine-211 (At-211) directly to tumor sites. When injected intraperitoneally into a mouse model of gastric cancer dissemination, DPCs, which were isolated and expanded, showed strong tumor-homing ability. Chemotaxis mediated by the CXCR4/SDF-1 axis has been reported to play a role in this accumulation. In addition to histological analysis, fluorescent imaging confirmed the selective accumulation of NIS-DPCs within tumor lesions. Introducing the NIS gene markedly increased SLC5A5 expression, enabling efficient At-211 uptake. To avoid nonspecific binding, sodium At-211 was utilized. High-resolution alpha-particle imaging visualized alpha-ray emission specifically from NIS-DPCs, confirming the radionuclides intracellular retention. In vivo, the sequential administration of NIS-DPCs, followed by Na[At-211], resulted in the pronounced regression of peritoneal tumors and a significant extension of survival compared to controls. The therapeutic mechanism involves three coordinated steps: tumor-directed migration of NIS-DPCs, At-211 uptake via NIS transporters, and localized alpha-particle-mediated cytotoxicity. This study introduces the novel concept of cell-based alpha-radiotherapy, which integrates regenerative and nuclear medicine. Due to the well-documented safety profile of DPCs in human clinical trials (J-REPAIR, jRCT1080224505), the NIS-DPC platform emerges as a promising approach for the precise, localized irradiation of disseminated gastric cancer and other challenging malignancies.