Sonodynamic Therapy: Concept, Mechanism and Application to Cancer Treatment.
Sonodynamic therapy (SDT) represents an emerging approach that offers the possibility of non-invasively eradicating solid tumors in a site-directed manner. It involves the sensitization of target tissues with a non-toxic sensitizing chemical agent and subsequent exposure of the sensitized tissues to relatively low-intensity ultrasound. Essentially, both aspects (the sensitization and ultrasound exposure) are harmless, and cytotoxic events occur when both are combined. Due to the significant depth that ultrasound penetrates tissue, the approach provides an advantage over similar alternative approaches, such as photodynamic therapy (PDT), in which less penetrating light is employed to provide the cytotoxic effect in sensitized tissues. This suggests that sonodynamic therapy may find wider clinical application, particularly for the non-invasive treatment of less accessible lesions. Early SDT-based approaches employed many of the sensitizers used in PDT, although the manner in which ultrasound activates the sensitizer differs from activation events in PDT. Here we will review the currently accepted mechanisms by which ultrasound activates sensitizers to elicit cytotoxic effects. In addition, we will explore the breath of evidence from in-vitro and in-vivo SDT-based studies, providing the reader with an insight into the therapeutic potential offered by SDT in the treatment of cancer.
School of Pharmacy and Pharmaceutical Sciences, University of Ulster, Coleraine, Co. Derry, BT2 1SA, UK.
Anthony P
AP
McHale
School of Pharmacy and Pharmaceutical Sciences, University of Ulster, Coleraine, Co. Derry, BT2 1SA, UK. j.callan@ulster.ac.uk.
John F
JF
Callan
Division of Surgery and Interventional Science, University College London, 4th Floor, 67-73 Riding House St, London, W1W 7EJ, England, UK.
Nikolitsa
N
Nomikou
School of Pharmacy and Pharmaceutical Sciences, University of Ulster, Coleraine, Co. Derry, BT2 1SA, UK.
Colin
C
Fowley
School of Pharmacy and Pharmaceutical Sciences, University of Ulster, Coleraine, Co. Derry, BT2 1SA, UK.
Bridgeen
B
Callan
D002986:Clinical Trials as Topic; D006801:Humans; D049449:Luminescence; D009369:Neoplasms / Q000628:therapy*; D010778:Photochemotherapy; D017382:Reactive Oxygen Species / Q000378:metabolism; D014464:Ultrasonic Therapy
D017382:Reactive Oxygen Species
Cancer; Reactive oxygen species; Sonodynamic therapy; Sonosensitizer; Ultrasound