Development of fluorescent- and radio-traceable T1307-polymeric micelles as biomedical agents for cancer diagnosis: biodistribution on 4T1 tumor-bearing mice

Abstract In recent years, nanocarriers have been studied as promising pharmaceutical tools for controlled drug-delivery, treatment-efficacy follow-up and disease imaging. Among them, X-shaped amphiphilic polymeric micelles (Tetronic®, poloxamines) display great potential due to their biocompatibility and non-toxic effects, among others. In the present work, polymeric micelles based on the T1307 copolymer were initially decorated with a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-fluorophore in order to determinate its in vivo biodistribution on 4T1 tumor-bearing mice. However, unfavorable results with this probe led to two different strategies. On the one hand, the BODIPY-micelle-loaded, L-T1307-BODIPY, and on the other hand, the 99mTc-micelle-radiolabeled, L-T1307- 99m Tc, were analyzed separately in vivo. The results indicated that T1307 accumulates mainly in the stomach, the kidneys, the lungs and the tumor, reaching the maximum organ-accumulation 2 hours after intravenous injection. Additionally, and according to the results obtained for L-T1307- 99m Tc, the capture of the polymeric micelles in organs could be observed up to 24 hours after injection. The results obtained in this work were promising towards the development of new radiotracer agents for breast cancer based on X-shaped polymeric micelles.

99mTc Stearyl 6-(benzylidenehydrazinyl) nicotinamide Liposomes as Tumor Permeability Evaluation Tracer.

Nanomedicine is a highly demanded discipline. Liposomes have seen an increased attention due to their physicochemical properties that allow them to act as nanocarriers of drugs and also of radioisotopes that can be used to diagnose and treat cancer. In order to obtain a novel permeability cancer imaging agent based on 99mTc-labeled liposomes, we describe microwave-assisted synthesis of stearyl 6-(benzylidenehydrazinyl) nicotinamide lipid, which was included in two formulations: nanometric hydrazinonicotinic acid (HYNIC) liposome and its PEGylated coated analogue, HYNIC-PEG liposome. Radiolabeling with 99mTc via stearyl 6-(benzylidenehydrazinyl) nicotinamide was found to be easy, reproducible, and stable, revealing high radiochemical purity (94 ± 1.7%) for both liposomal formulations. Biodistribution at 4 h and 24 h and scintigraphic images at 4 h were performed in normal and melanoma-bearing C57BL/6 mice. Biodistribution studies at 4 h showed tumor uptake of 99mTc-HYNIC liposome and 99mTc-HYNIC-PEG liposome (1.1 ± 0.6 and 2.5 ± 0.4, respectively) and also at 24 h p.i. (1.8 ± 0.5 and 3.0 ± 1.1, respectively). Scintigraphic images showed appreciable tumor uptake in melanoma tumor-bearing mice with both liposomal formulations. Our results show that 99mTc stearyl 6-(benzylidenehydrazinyl) nicotinamide liposomes can be used as diagnostic noninvasive in vivo tumor-targeting agents capable of evaluating tumor permeability and development who can be used in personalized chemotherapy planning.

Development and Evaluation of 2-Amino-7-Fluorophenazine 5,10-Dioxide Polymeric Micelles as Antitumoral Agents for 4T1 Breast Cancer.

2-Amino-7-fluorophenazine 5,10-dioxide (FNZ) is a bioreducible prodrug, poorly soluble in water, with potential anticancer activity on hypoxic-tumors. This poor solubility limits its potential applications in clinic. Amphiphilic pristine polymeric micelles (PMs) based on triblock copolymers Pluronic® and Tetronic®, glycosylated derivatives and their mixtures with preformed-liposomes (LPS), were analyzed as strategies to improve the bioavailability of FNZ. FNZ encapsulations were performed and the obtaining nanostructures were characterized using UV-visible spectroscopy (UV-VIS), Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS). The most promising nanoformulations were analyzed for their potential toxicity and pharmacologically, at 20 mg/kg FNZ-doses, in a stage-IV murine metastatic-breast tumor model. The results revealed that the solubility of the encapsulated-FNZ increased up to 14 times and the analysis (UV-VIS, DLS and TEM) confirmed the interaction between vehicles and FNZ. In all the cases appropriate encapsulation efficiencies (greater than 75%), monodisperse nanometric particle sizes (PDI = 0.180-0.335), adequate Z-potentials (-1.59 to -26.4 mV), stabilities and spherical morphologies were obtained. The in vitro profile of FNZ controlled releases corresponded mainly to a kinetic Higuchi model. The in vitro/in vivo biological studies revealed non-toxicity and relevant tumor-weight diminution (up to 61%).

Carboranylanilinoquinazoline EGFR-inhibitors: toward 'lead-to-candidate' stage in the drug-development pipeline.

Background: Carboranylanilinoquinazoline-hybrids, developed for boron neutron capture therapy, have demonstrated cytotoxicity against murine-glioma cells with EGFR-inhibition ability. In addition, their adequate aqueous/metabolic stabilities and ability to cross blood-brain barrier make them good leads as to become antiglioma drugs. Aim: Analyze drug-like properties of representative carboranylanilinoquinazolines. Materials & methods: To expand carboranylanilinoquinazolines therapeutic spectrum, we studied their ability to act against glioma-mammal cells, U-87 MG and other tyrosine kinase-overexpress cells, HT-29. Additionally, we predicted theoretically and studied experimentally drug-like properties, in other words, organization for economic cooperation and development-recommended toxicity-studies and, due to some aqueous-solubility problems, and vehicularization for oral and intravenous administrations. Conclusion: We have identified a promising drug-candidate with broad activity spectrum, appropriate drug-like properties, adequate toxicological behavior and able ability to be loaded in suitable vehicles.

In vitro and in vivo uptake studies of PAMAM G4.5 dendrimers in breast cancer.

BACKGROUND: Breast cancer is the second leading cause of cancer death worldwide. Nanotechnology approaches can overcome the side effects of chemotherapy as well as improve the efficacy of drugs. Dendrimers are nanometric size polymers which are suitable as drug delivery systems. To the best of our knowledge, studies on the application of PAMAM G4.5 (polyamidoamine half generation 4) dendrimers as potential drug delivery systems in breast cancer have not been reported. In this work we developed a PAMAM G4.5 dendrimer containing FITC (fluorescein isothiocyanate) dye to study their uptake by murine breast cancer cells and BALB/c mice breast tumors. RESULTS: We performed a reaction between FITC and PAMAM G4.5 dendrimers which were previously derivatized with piperazine (linker molecule), characterized them by (1)H NMR (proton nuclear magnetic resonance) spectroscopy and MALDI-TOF (matrix-assisted laser desorption/ionization- time-of-flight) mass spectrometry. The experimental data indicated that 2 FITC molecules could be bound covalently at the PAMAM G4.5 dendrimer surface, with 17 FITC molecules probably occluded in PAMAM dendrimers cavity. PAMAM-FITC dendrimer (PAMAM G4.5-piperazinyl-FITC dendrimer) size distribution was evaluated by DLS (dynamic light scattering) and TEM (transmission electron microscopy). The nanoparticle hydrodynamic size was 96.3 ± 1.4 nm with a PdI (polydispersion index) of 0.0296 ± 0.0171, and the size distribution measured by TEM was 44.2 ± 9.2 nm. PAMAM-FITC dendrimers were neither cytotoxic in 4T1 cells nor hemolytic up to 24 h of incubation. In addition, they were uptaken in vitro by 4T1 cells and in vivo by BALB/c mice breast tumors. PAMAM G4.5-piperazinyl-FITC dendrimer intracellular distribution was observed through histologic analysis of the tumor by laser confocal microscopy. CONCLUSION: These results indicate that PAMAM G4.5 dendrimers enter tumor tissue cells, being good candidates to be used as antitumor drug delivery systems for breast cancer treatment and diagnosis.