Nanoparticle-Modified Apoferritin Nanotransfer for Targeted Cytostatic Transport.

BACKGROUND: Ferritin is a globular intracellular protein that acts as the main reservoir for iron. Malignancies are associated with increased plasma ferritin concentrations. A number of studies show that tumor cells express high levels of transferrin receptors (TfR). Increased TfR expression was observed in prostate carcinoma. Apoferritin (APO) can be used as a protein nanotransporter into which a suitable medicinal substance can be encapsulated. Nanoparticles increase the permeability of tumor cells to nanotransporters and have a photothermal effect. The aim of this study was to encapsulate doxorubicin (DOX) into APO and to modify the resulting APO/DOX with gold (AuNPs) and silver nanoparticles prepared by green synthesis (AgNPsGS). METHODS: APO was characterized using 10% sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE) - 120 V, 60 min, 24 mM Tris, 0.2 M glycine, 3 mM SDS. DOX fluorescence (Ex 480 nm; Em 650 nm) was observed, with a typical absorption maximum at 560 nm. Electrochemical measurement was performed in Brdicka solution (three-electrode setup). AgNPsGS were prepared by green synthesis using clover (Trifolium pratense L.). RESULTS: An electrophoretic study of APO and APO/DOX (5-100 μg/mL) was performed and the behavior of APO and APO/DOX (10 μM) as a function of pH was monitored. In an acidic environment, APO forms subunits of about 20 kDa; in an alkaline medium, it forms a globular protein of about 450 kDa. A change in APO/DOX mobility (about by 10%) was observed. A film of gold nanoparticles was applied to the APO/DOX surface. APO/DOX-AuNPs were washed with ultra-pure water. pH-dependent release of DOX a was monitored. The amount of DOX analyzed was increased by up to 50%. Furthermore, an AgNPsGS-DOX complex (1 mg AgNPsGS/100 μM DOX) was generated and prepared. Subsequently, the AgNPsGS-DOX complex was encapsulated into APO. To further improve therapeutic efficacy, the APO/AgNPsGS-DOX complex was coated with an Au layer. APO/AgNPsGS-DOX/AuNPs were stable and DOX was released from the complex after physical parameters had changed. CONCLUSION: APO nanocomplexes were prepared and modified to increase therapeutic efficacy against tumors. Tumor cell targeting was achieved by binding to TfR and via increased tumor cell permeability and retention. Release of the drug was made possible due to a pH change and photothermal activation that will now be tested. This work was supported by COST European Cholangiocarcinoma Network CA18122 and International Collaboration Project of The European Technology Platform for Nanomedicine. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 21. 3. 2019 Accepted: 14. 5. 2019.

[Fullerene Doxorubicin Nanotransporter for Target Interaction with mutated gene BRCA2]. / Fullerenový nanotransportér doxorubicinu pro cílenou interakci s mutovaným genem BRCA2.

BACKGROUND: Malignant breast tumors are in developed countries, the most common cancer affecting mainly women. It is estimated that approximately 5-10% of breast cancers are conditioned by genetic family burdens, caused by mutation in the BRCA2 gene. In the course of the treatment doxorubicin is frequently used therapeutics. Despite its therapeutic efficacy, however, it shows high cardiotoxicity. Possibility to increase the therapeutic window, represent nanotransporters. Fullerenes are nanoparticles composed of carbon atoms whose physical-chemical properties indicate high stability. The complex of fullerene and doxorubicin enables the targeted method for the treatment. The aim of this work is to develop a nanotransporter system with an expected cytostatic effect without significant toxic effects. MATERIAL AND METHODS: To 5mg of fullerene 0.5ml of distilled water was added and solution was subsequently placed for 30 min in an ultrasonic bath (50 W). Fullerenes with bound doxorubicin (DOXO) were purified from unbound DOXO by centrifugation (16,000g). For DOXO analysis acetate buffer was used. Fe2O3-NPs were prepared by reduction with borohydride and ammonia. Thereafter Fe2O3-AuNPs were prepared by thermal synthesis. RESULTS: Carbon nanotransporter (fullerene) for binding of doxorubicin (FULLER-DOXO) was designed and subsequently studied by biophysical methods. We have found that FULLER-DOXO size is larger than 100 nm and the zeta potential is around 24 mV. DOXO, interacts with FULLER by the electrostatic interaction, and its volume increases with the applied concentration (R2 = 0.96). In the following experiment FULLER-DOXO was modified with oligodeoxynucleotide (ODN; 10 µg/ml), and this way was FULLER-DOXO-ODN1 complex prepared. Bound ODN represents a specific sequence for targeting the complex to a point mutation in the BRCA2 gene. In order to prove the interaction magnetic gold nanoparticle modified with the complementary sequence to the test nanotransporter was designed (ODN2-Fe2O3-AuNPs). Formed complex (FULLER-DOXO-ODN1-ODN2-Fe2O3-AuNPs) was subsequently confirmed by several independent techniques. CONCLUSION: We assume that the proposed nanoconstruct will be able to use for genetic targeting of anticancer drug.Key words: doxorubicin - breast cancer - fullerenes - magnetic gold nanoparticles The work was realized with the support of the project NANO LPR 2017 Liga proti rakovine Praha and The European Technology Platform for Nanomedicine. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 6. 3. 2017Accepted: 26. 3. 2017.