Ultrasound-Mediated Destruction of LHRHa-Targeted and Paclitaxel-Loaded Lipid Microbubbles Induces Proliferation Inhibition and Apoptosis in Ovarian Cancer Cells

Although paclitaxel (PTX) is used with platinum as the first line chemotherapy regimen for ovarian cancer, its clinical efficacy is often limited by severe adverse effects. Ultrasound-targeted microbubble destruction (UTMD) technique holds a great promise in minimizing the side effects and maximizing the therapeutic efficacy. However, the technique typically uses nontargeted microbubbles with suboptimal efficiency. We synthesized targeted and PTX-loaded microbubbles (MBs) for UTMD mediated chemotherapy in ovarian cancer cells. PTX-loaded lipid MBs were coated with a luteinizing hormone-releasing hormone analogue (LHRHa) through a biotin avidin linkage to target the cancer A2780/DDP cells that express the LHRH receptor. In the cell culture studies, PTX-loaded and LHRHa-targeted MBs (TPLMBs) in combination with ultrasound (300 kHz, 0.5 W/cm(2), 30 s) demonstrated antiproliferative activities of 41.30 +/- 3.93%, 67.76 +/- 2.45%, and 75.93 +/- 2.81% at 24, 48, and 72 h after the treatment, respectively. The cell apoptosis ratio at 24 h after the treatment is 32.6 +/- 0.79%, which is significantly higher than other treatment groups such as PTX only and no-targeted PTX-loaded MBs (NPLMBs) with or without ultrasound mediation. Our experiment verifies the hypothesis that ultrasound mediation of ovarian cancer-targeted and drug-loaded MBs will enhance the PTX therapeutic efficiency.