ホウ素中性子捕捉療法（BNCT）がヒト胆管がん細胞株にDNA損傷を誘発する

Boron neutron capture therapy (BNCT) is a radiation therapy based on the nuclear reaction between ¹⁰B and neutrons to induce DNA damage in cancer cells. This study aims to evaluate ¹⁰B accumulation in the human cholangiocarcinoma cell line (KKU-055) and measure the cellular response to BNCT.

The cytotoxicity of ¹⁰B on KKU-055 cell line was observed with different L-BPA fructose concentrations. The amount of ¹⁰B in cells was measured via inductively coupled plasma - mass spectrometry. Cells treated with various ¹⁰B concentrations were exposed to thermal neutron beams with a flux of 1.89 x 10⁹ n cm^-2 s^-1 for 5 and 30 min. Survival curve and DNA damage were measured to demonstrate the biological endpoints of cells after irradiation.

The cytotoxicity test revealed that L-BPA fructose up to 51 ppm of ¹⁰B is less toxic to the cells with >85% of the control. ¹⁰B accumulation in cells was time-dependent, reaching a maximum of 0.126 ppm after 24 h. The number of γH2AX foci was increased in ¹⁰B concentration- and irradiation time-dependent manner. A significant decrease in survival fraction was observed after 5 min of BNCT irradiation, with survival fraction dropping to 11.7%.

These findings showed a high accumulation of ¹⁰B in KKU-055 cells could be observed after 24 h. BNCT has proven effective in increasing the radiosensitivity of KKU-055 cell line and enhancing cell death in KKU-055 cells. Therefore, BNCT is a promising technique for cholangiocarcinoma treatment.