High Energy Shock Waves (HESW) for Sonodynamic Therapy: Effects on HT-29 Human Colon Cancer Cells

Background: Whether high energy shock waves (HESW), generated by a piezoelectric generator, were able to activate a sonosensitizer, 5-aminolevulinic acid (ALA) and induce inhibition of cell growth in HT-29 human colorectal cancer cells was investigated. Materials and Methods: Cell survival and cell death pathways were investigated by cell growth curves, flow cytometry analysis and ELISA nucleosome evaluation. HT-29 cells were exposed to ALA and different HESW treatments: E1 (energy flux density = 0.22 mJ/mm 2 ; 500 and 1000 shots) and E2 (energy flux density = 0.88 mJ/mm 2 ; 500 and 1000 shots). Results: A significant reduction of HT-29 cell growth with respect to untreated cells was observed only after treatment with ALA and HESW E2, 500 shots. In particular, HESW E2, 500 shots, was able to induce an arrest of HT-29 cells exposed to ALA in the G 0 /G 1 -phase of the cell cycle. Conclusion: HESW is proposed for the sonodynamic treatment of cancer cells.