Short interference RNA introduced into cultured cells with diagnostic ultrasound.

Diagnostic ultrasound (US) is safe. Short interference (si) RNA of Frizzled (Fz)-9 suppresses proliferation of hepatocellular carcinoma cells. siRNA was introduced into Hep3B cells, a human hepatocellular carcinoma cell line, with transfection or US upward to culture plates at mechanical index (MI) = 0.4 or 0.8. siRNA of Fz9 was introduced for western blot analysis and cell proliferation assay. siRNA of Fz9 suppressed cell proliferation to 32.8±13.6% at 200 nM (P<0.0001) with transfection. With US, cell proliferation decreased to 36.9±15.1% at 200 nM (P=0.039) at 0.4 of MI while 49.2±12.0% at 200 nM (P=0.041) at MI=0.8. Western blot analysis showed that 200 nM of siRNA decreased the expression of Fz9 with US at MI=0.4 and MI=0.8. No change was seen in cell proliferation between transfection and US. siRNA was introduced into cultured cells and functioned with US.