In vivo investigation of high-intensity focused ultrasound combined with thermally triggered chemotherapy for liver cancer treatment

High-Intensity Focused Ultrasound (HIFU) induces rapid tissue heating and mechanical disruption and also provides noninvasive release of chemotherapy from temperature-sensitive-liposomes (TSLs). We evaluated the combination of Sorafenib-loaded TSLs (SfTSLs) and HIFU via analysis of cell viability, tumor growth, and long-term survival. Liposomes were encapsulated with Sorafenib at 10μM with a glass transition temperature of 43°C. Hep3B human liver cancer cells were placed in PCR tubes to mimic dense tumor aggregates. Aggregates were treated with HIFU alone, SfTSLs alone, or SfTSLs + HIFU. HIFU exposure was applied for 30 seconds at acoustic output powers of 8.7 and 12W. Cell viability and proliferation were measured over 4 days post-treatment via AnnexinV/PI and WST-8 staining. Xenografted tumors were created via injection of 1.0×106 Hep3B cells within Matrigel into flanks of athymic-nude mice. Tumors at 8–10 mm were separated into the following groups: Control (sham), HIFU, SfTSLs, and SfTSLs + HIFU. Tumors were measured daily with endpoints at 5 days, 14 days, or long-term survival. Dissected tumors were H&E stained and evaluated by a blinded pathologist. The in vitro data indicates that Hep3B cells exposed to SfTSLs + HIFU have a significantly lower viability and proliferation rate. Similarly, in vivo results show SfTSLs + HIFU reduces tumor growth and increases survival.