Chemotherapeutic Boron-Containing Homocysteinamides of Human Serum Albumin

Objective: A combination of boron neutron capture therapy and chemotherapy can ensure good efficacy in cancer treatment. The development of therapeutic constructs that combine these two functions, specifically the possibility of in vitro and in vivo visualization and a convenient platform for selective delivery to the tumor, is of great relevance today. Methods: In this study, we focused on human serum albumin, a well-known drug delivery platform, and developed, based on albumin functionalized with boron clusters, therapeutic constructs, which as analogs of the chemotherapeutic molecule gemcitabine and signaling molecules. To create such constructs, we developed new analogs of homocysteine thiolactone containing closo-dodecaborate or cobalt bis(dicarbollide) and a gemcitabine analog containing closo-dodecaborate attached to the C⁵ carbon atom of the nitrogenous base. Results and Discussion: It was demonstrated that the the conjugates modified with the gemcitabine analogs exhibit increased cytotoxicity against human glioblastoma cell lines. Among the obtained conjugates, the highest cytotoxicity is demonstrated by that containing cobalt bis(dicarbollide). The resulting structures accumulate well in the cytoplasm of cancer cells. The albumin conjugate containing cobalt bis(dicarbollide) and the boron-containing gemcitabine analog is capable of accumulating in the nuclei of T98G cell lines. Conclusions: The resulting albumin constructs showed sufficient in vitro activity against human glioma cells. It is expected that the obtained therapeutic conjugates will significantly enhance the anticancer efficacy of irradiation with epithermal neutrons. Combining a chemotherapeutic residue and a boron-containing group in a single construct provides potential for more effective glioma therapy.