Empowering radiation therapy effect through a nanotechnology based enzymatic therapy

Abstract

Introduction One of the main effects during interaction of radiation with aqueous molecules contained into living cell is free radicals generation. d -Amino acid oxidase (DAO) enzyme also generates free radicals. Purpose Starting from this evidence we decided to investigate the combined effects of radiotherapy and DAO on primary cultures of glioblastoma multiforme (GBM), in order demonstrate the supposed improvement of the results obtained by the sole radiation. Materials and methods We used primary cultures of GBM obtained from patients’ removed tumors. Recombinant DAO enzyme is obtained from cultures of E. coli. Enzyme is immobilized on magnetic nanoparticles with coated magnetite core Dietil-amino-etil cellulose. Cultures were irradiated at doses of 7 Gy and 15 Gy with photons of 6 MV produced by a linear accelerator for radiotherapy. After irradiation some samples were treated with DAO both free and immobilized in magnetic nanoparticles. Biological effects on culture cells were measured by flow cytometry to determine cell cycle phases distribution. Results Results obtained by our group on primary cultures of GBM, show a dramatic potentiation of radiation effects after DAO, both free or immobilized in magnetic nanoparticles, was added to irradiated samples. Conclusion We were able to demonstrate that incubation of primary cultures of glioblastoma with DAO enzyme after irradiation with 6 MV X-Rays radiation, enhances the effect of radiation, increasing the fraction of dead cells. This effect is probably caused by the increase of free radicals induced DAO in addition to those produced by irradiation. Nanoparticles immobilized DAO is more stable than the free enzyme and therefore its enhancer effect is even greater. Disclosure Authors disclose any relationship that may bias this work.