In vivo anti-tumor activity of photodynamic therapy with intravenous administration of acridine orange, followed by illumination with high-power flash wave light in a mouse osteosarcoma model

Abstract

Abstract. In a recent study, we demonstrated that a high-power flash wave light (FWL) from a xenon lamp exerted a stronger cytocidal effect against a mouse osteosarcoma cell line than continuous wave light (CWL) in photodynamic therapy with acridine orange (AO-PDT). Based on our in vitro results, we investigated the in vivo anti-tumor activity of AO-PDT using flash wave light from a xenon lamp in a mouse osteosarcoma model. Mouse osteosarcoma cells (LM8) were injected into the subcutaneous tissue of the back of C3H mice, and tumors that grew to approximately 3 mm in diameter were treated by AO-PDT using FWL. AO was administered by intravenous injection and 2 h later the entire body of the mouse was illuminated with FWL from a xenon lamp. Significant growth inhibition of the tumor xenografts was observed as compared with that in the control group, suggesting that AO-PDT with FWL may be useful in the treatment of osteosarcoma. An immunohistochemical study of the tumors treated by AO-PDT showed that the underlying mechanism of the tumor growth inhibition involved both apoptosis and necrosis. In conclusion, it appears that following the intravenous administration of AO, AO-PDT in combination with FWL exerts strong anti-tumor activity. Inhibitory effects against growth of the primary tumor in human patients with osteosarcoma as well as other musculoskeletal sarcomas were also observed.

Neurosurgical Flexible Probe Microscopy with Enhanced Architectural and Cytological Detail

“…Acridine orange and other nuclear contrast agents such as acriflavine and proflavine, have been used as in vivo nuclear contrast agents for microscopy. [40][41][42][43][44] The use of nuclear contrast agents in vivo for neuropathologic assessment may be of importance because nuclear assessment is critical for the diagnosis of many neurologic tumors. Acridine orange has also been recently demonstrated as a potential agent for neuro-oncologic photodynamic therapy.…”

Radiodynamic therapy with acridine orange local administration as a new treatment option for primary and secondary bone tumours

“…When exposed to low doses of radiograph radiation, AO also increases the production of reactive radicals. 4 Kusuzaki et al 1 and Satonaka et al 3 , 7 developed photodynamic and radiodynamic therapies with AO (AO-PDT and AO-RDT) using in vitro and in vivo studies. In addition, other studies observed excellent clinical outcomes in patients with bone and soft-tissue sarcomas who received AO-PDT and AO-RDT.…”