CYTOTOXIC AND ANTIPROLIFERATIVE EFFECTS OF HIGH-ENERGY PULSED ULTRASOUND (HEPUS) ON HUMAN SQUAMOUS-CELL CARCINOMA-CELLS AS COMPARED TO CONNECTIVE-TISSUE FIBROBLASTS

The cytotoxic and anti-proliferative effects of high-energy pulsed ult rasound (HEPUS) on human squamous cell carcinoma cells cloned from the hypopharynx (FaDu) and benign connective tissue cells (fibroblasts) w ere investigated in vitro. Sonication was carried out using an experim ental piezoelectric, self-focusing burst-signal transducer. To increas e the induction of cavitation, the transducer used was specifically de signed to produce multiple oscillations with a high negative pressure amplitude. In both cell lines tested, the application of 100, 800 and 2000 pulses resulted in a high reduction of vital cells. After 2000 pu lses, 4.0 +/- 1.1% of the fibroblasts but only 2.0 +/- 0.3% of the FaD u cells survived HEPUS exposure. A postexposure inhibiting effect of H EPUS for 10 days on the proliferation of surviving cells was noted for the FaDu cells exposed to 2000 pulses, but not as much for the fibrob lasts. These findings support the hypothesis that human squamous cell carcinoma cells of the hypopharynx might be more sensitive to HEPUS th an fibroblasts and that total tumor cell ablation might be possible in vitro given a sufficient number of HEPUS pulses.