Sonodynamic Therapy: Concept, Mechanism and Application to Cancer Treatment

Abstract

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.

5-Aminolevulinic Acid-Mediated Sonodynamic Therapy Alleviates Atherosclerosis via Enhancing Efferocytosis and Facilitating a Shift in the Th1/Th2 Balance Toward Th2 Polarization

“…It is now clear that when exposed to ultrasound, the porphyrin-based sensitizers generate ROS, causing cytotoxicity [40]. Consistent with this finding, we found that ALA-SDT increased the intracellular ROS levels in Jurkat cells (Fig.…”

Nanoparticles of Titanium and Zinc Oxides as Novel Agents in Tumor Treatment: a Review

“…An example of an alternative tumor eradication method is SDT. This therapy is based on a synergistic effect on a cancer cell by sonosensitizer and US [199]. US can activate particles of compounds called sonosensitizers.…”

“…In comparison with UV or NIR radiation, US penetrates tissues much more effectively as it reaches deeper depths tumor cells. The introduction of sonosensitizers into cancer cells and their subsequent exposure to US in order to generate ROS is the underlying factor of SDT [199, 200] (Fig. 2).…”

Oxygen and indocyanine green loaded phase-transition nanoparticle-mediated photo-sonodynamic cytotoxic effects on rheumatoid arthritis fibroblast-like synoviocytes

“…Compared with the light used in PDT, ultrasound has better penetrability, which can easily act on the lesion at a deep site. 11,12 Besides, it is currently believed that the combination of PDT and sonodynamic therapy (SDT) may decrease the sensitizer dosage and ultrasound/ light energy, which can further reduce the side effects, while enhancing the curative effect dramatically. [13][14][15][16][17] Thus, PDT combined with SDT (PSDT) is considered for the lesion of deep site in the present study.…”