[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.

[Zinc-modified Nanotransporter for Target Drug Therapy of Breast Cancer]. / Zinecnatými ionty modifikovaný nanotransportér antracyklinových antibiotik pro cílenou terapii nádoru prsu.

BACKGROUND: In the centre of nanomedical interest stands the nanotechnological modification of anthracycline antibiotics, which are often used in antitumor treatment of hematological malignancies and solid tumors. Chitosan nanoparticles are gaining more attention in the field of targeted transport of drugs because of their stability, low toxicity and simple preparation. The main objective of the project, was the design of chitosan nanotransporter of anthracycline antibiotics with zinc modified surface, for a specific interaction with metallothionein. MATERIAL AND METHODS: The chitosan nanoparticles with encapsulated doxorubicin were prepared by a dissolution of 5g of chitosan in 3% solution of acetic acid and TPP (0.25% w/v) and doxorubicin (0.5mg/ml). Fe2O3-NPs were prepared by a reduction with borohydride and using ammonia. Thereafter Fe2O3-AuNPs were prepared by thermal synthesis. The amount of doxorubicin and Zn2+ was determined using DPV. RESULTS: Chitosan nanotransporter with anthracycline antibiotics (CHIT-Zn-DOXO-Fe2O3-AuNPs) was designed and subsequently studied by biophysical methods. Inside of the nanometric structure is electrostatically bound doxorubicin (concentration 10 µM, CHIT-DOXO). Moreover metallothionein is a molecule rich in cysteine and thanks to its free sulphhydryl groups is capable of bonding with the zinc ions. We have decided to use this ability for a construction of the nanotransporter for its targeted direction towards the tumor tissue (CHIT-Zn-DOXO). We have shown significant increases of a metallothionein (MT) level in malignant tumors in many of our previous experiments. MT into its domains binds heavy metal ions (naturally zinc ions) and keeps the homeostasis in equilibrium this way. Therefore we have decided to observe the ability of modified chitosan nanoparticles (CHIT-Zn-DOXO, 100 µg/ml) for MT protein binding (magnetic gold nanoparticles were modified by MT, 100 µg/ml, Fe2O3-AuNPs) in the other part of our experiment. The efficiency of the chitosan nanoparticle bond modified by zinc ions (CHIT-Zn-DOXO) to the MT (CHIT-Zn-DOXO-Fe2O3-AuNPs-MT) increased by more than 30% compared with the unmodified nanoparticle (CHIT-DOXO). CONCLUSION: We assume that the new nanotransporter is specific for its bioavailability, increased uptake of the drug from bloodstream in the tumor tissue area and low toxicity for an untargeted tissue.Key words: chitosan - magnetic gold nanoparticles - breast cancer - doxorubicin The work was realized with the support of the project NANODRUGS 328/2017/FaF 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.