Radiodynamic Therapy with Acridine Orange Is an Effective Treatment for Bone Metastases

Research Overview

Treatment of bone metastases is only partly effective and often burdened by side effects. Acridine orange is a photosensitizer that accumulates in acidic compartments and, once activated by light or radiation, triggers lysosome-mediated cell death. This study explored radiodynamic activation of acridine orange as an acid-targeted therapy for bone metastases.

Using osteotropic carcinoma cells and human osteoclasts, the authors measured extracellular acidification, invasiveness, acridine orange uptake, lysosomal pH and stability, and radiodynamic cytotoxicity in vitro, then compared the approach against omeprazole — another anti-acid strategy — in a xenograft model. Carcinoma cells acidified their surroundings, and that tumor-derived acidosis enhanced invasiveness.