Evaluation of Boron Content Liposome Modified Protein- Transduction Domains for Boron Neutron Capture Therapy

One of the radiotherapy has boron neutron capture therapy (BNCT). They may make it easier to kill tumor cells with BNCT. In BNCT, it is important for boron agents, which have high selectively and high accumulation, to be introduced into tumor cells. To date, the main boron compounds used by the clinical study are sodium mercaptododecaborate (BSH) and pboronophenylalanine (BPA). But, there are no ideal boron compounds that all fulfill boron concentration required treatment, low toxicity, water solubility, low distribution in normal tissue, and high yield. So, we studied it to solve these conditions. We previously succeeded in synthesizing a boron compound-conjugated lipid analog and peptide (lipopeptide), and have now developed a liposome using that lipopeptide. First, we report here on the availability of the liposome in vitro. The liposome achieved a higher boron concentration than that in BSH solution. Thus, the liposome shows cell introduction ability. Furthermore, the liposome can be contained in BSH, and is able to increase the cellular boron concentration. Second, we report here on the availability of the liposome modified lipopeptide with neutron irradiation. The liposome modified lipopeptide is shown cytotoxicity to Colon cancer cell lines (CT26) after thermal neutron irradiation. Keywords— boron neutron capture therapy (BNCT), drug delivery system (DDS), liposome