Multimodal Thermo-sensitive Polymer-modified Liposome for Visualization and Treatment of Disseminated Cancer

Introduction The purpose of this study is to visualize the dynamics of accumulation of and the drug release from a nano-carrier using a multimodal temperature-sensitive liposome (TSL) that contains an anticancer drug, a fluorescent dye and a MR contrast agent for disseminated cancer treatment. A drug delivery system (DDS) using the TSL with doxorubicin has previously been developed to increase the treatment efficacy in the heated area and to decrease the side-effects of the anticancer drug in the intact organ [1, 2]. Additionally, the dynamics of drug release in fibrosarcoma has been visualized using MR contrast agent-containing TSLs [3, 4]. In previous work, we reported that a multimodal thermo-sensitive ‘polymer-modified’ liposome (MTPL) allows more accurate drug-release and that it can be loaded with various functional agents such as doxorubicin, rhodarmine, and MnSO4 [5]. The MTPL accumulated in the subcutaneous tumor for over 8 hours after administration, and the temperature-triggered drug-release was visualized as a signal enhancement in T1-weighted MRI [5]. As the next step, the MTPL was applied to an advanced-stage disseminated/metastatic cancer. Clinically, the benefits of treatment are not yet satisfactory although with advances in the methodology improvement is anticipated [6]. To improve the applicability of MTPL to the treatment of disseminated/metastatic cancer, the dynamics of MTPL accumulation and the detection of drug release were examined using both MRI and optical imaging.