Cytotoxicity and accumulation of lithium chloride enriched with lithium-6 isotope as a potential agent for lithium-neutron capture therapy

Boron neutron capture therapy is an innovative technology for treating a number of malignant neoplasms. A promising replacement for the boron-10 isotope is lithium-6, which has a high thermal neutron capture cross-section, and the reaction is characterized by localized energy release. Material and methods. To implement the lithium neutron capture therapy (LiNCT) method, preliminary in vitro studies were conducted with lithium chloride enriched with the lithium-6 isotope. Cytotoxicity was assessed using the MTT test, and lithium accumulation by DF-1, C2C12, RD и T98-G cells was measured using inductively coupled plasma atomic emission spectrometry. Results and discussion. Lithium chloride at a dose of 6 mM did not reduce cell viability when co-cultured for up to 24 hours. Lithium accumulation did not depend on the incubation time when cells were cultured with lithium chloride at this dosage. The highest lithium concentration was detected in human dermal fibroblasts DF-1, while the lowest was in mouse limb muscle cells C2C12. The detected lithium concentrations were comparable to boron concentrations in in vitro experiments using a non-selective boron delivery agent (borocaptate). Conclusions. Lithium chloride enriched with lithium-6 isotope can be used for LiNCT. The development of targeted nanocomposites will increase lithium accumulation by cells and enhance the efficacy of LiNCT.