RESUMO
<p><b>OBJECTIVE</b>To study whether antisense oligonucleotides and ultrasonic microbubble intensifier transfection combined with ultrasound irradiation is an effective and directional way in reversing multidrug resistance (MDR) in tumors.</p><p><b>METHODS</b>Mdr1, mrp, and lrp genes antisense oligonucleotides on the ultrasound microbubble intensifier were transfected for the human HepG2/ADM cell lines and then the cells were radiated with low intensity ultrasound. The effects of the reversion of carcinoma cells' MDR and the reduction of their malignancy and growth capability in vitro and in vivo were assessed using RT-PCR, Western blot and MTT.</p><p><b>RESULTS</b>The treatment restrained the multiplication of the human HepG2/AMD cell lines. The levels of their mRNA and protein of cells' mdr1 and mrp genes dropped significantly. Growth of the subcutaneous transplanted tumors in the nude mice decreased.</p><p><b>CONCLUSIONS</b>Transfection of MDR genes antisense oligonucleotides on the ultrasonic microbubble intensifier combined with low intensity ultrasound radiation may serve as a new treatment method for hepatocellular carcinoma.</p>