Sublethal and potentially lethal damage repair on thermal neutron capture therapy

Area of Science:

• Radiobiology
• Cellular Radiation Response
• Cancer Therapy

Background:

• Potentially lethal damage (PLD) repair influences cell survival after irradiation.
• Caffeine and tonicity shock are known to enhance the expression of fast-type PLD.
• Melanoma cells exhibit radioresistance, posing a challenge for conventional therapies.

Purpose of the Study:

• To compare the efficacy of caffeine and tonicity shock in revealing fast-type PLD in X-irradiated B-16 melanoma cells versus V79 Chinese hamster cells.
• To investigate the repair of sublethal damage (SLD) and fast-type PLD by thermal neutron irradiation in V79 and B-16 cells.
• To evaluate the effectiveness of boron neutron capture therapy (BNCT) using 10B1-paraboronophenylalanine (BPA) for eradicating melanoma cells.

Main Methods:

• X-irradiation and thermal neutron irradiation of V79 and B-16 cells.
• Post-irradiation treatment with caffeine or tonicity shock to assess fast-type PLD.
• Analysis of survival curves to determine SLD and PLD repair.
• Preincubation of B-16 cells with 10B1-BPA followed by thermal neutron irradiation.

Main Results:

• Caffeine more efficiently expressed fast-type PLD in X-irradiated B-16 cells than tonicity shock.
• Thermal neutron irradiation did not induce SLD repair or significant fast-type PLD repair in either cell type.
• 10B1-BPA preincubation followed by thermal neutron irradiation effectively eradicated melanoma cells, with minimal fast-type PLD repair observed.
• Plateau-phase B-16 cells repaired X-ray-induced slow-type PLD but not thermal neutron-induced slow-type PLD.

Conclusions:

• Thermal neutron capture therapy using 10B1-BPA demonstrates significant potential for eradicating radioresistant melanoma cells.
• The therapy is effective against both proliferating and quiescent melanoma cells.
• Understanding PLD repair mechanisms is crucial for optimizing radiation therapy strategies.