Related Experiment Video
Updated: Jul 13, 2025
Polymalic Acid-based Nano Biopolymers for Targeting of Multiple Tumor Markers: An Opportunity for Personalized Medicine?
Published on: June 13, 2014
Imidazo-Pyrazole-Loaded Palmitic Acid and Polystyrene-Based Nanoparticles: Synthesis, Characterization and
Giulia Elda Valenti1, Barbara Marengo1, Marco Milanese2
1Department of Experimental Medicine (DIMES), University of Genova, Via Alberti L.B., 16132 Genoa, Italy.
Abstract:
Neuroblastoma (NB) is a childhood cancer, commonly treated with drugs, such as etoposide (ETO), whose efficacy is limited by the onset of resistance. Here, aiming at identifying new treatments for chemo-resistant NB, the effects of two synthesized imidazo-pyrazoles (IMPs) (4G and 4I) were investigated on ETO-sensitive (HTLA-230) and ETO-resistant (HTLA-ER) NB cells, detecting 4I as the more promising compound, that demonstrated IC50 values lower than those of ETO on HTLA ER. Therefore, to further improve the activity of 4I, we developed 4I-loaded palmitic acid (PA) and polystyrene-based (P5) cationic nanoparticles (P5PA-4I NPs) with high drug loading (21%) and encapsulation efficiency (97%), by a single oil-in-water emulsification technique. Biocompatible PA was adopted as an emulsion stabilizer, while synthesized P5 acted as an encapsulating agent, solubilizer and hydrophilic-lipophilic balance (HLB) improver. Optic microscopy and cytofluorimetric analyses were performed to investigate the micromorphology, size and complexity distributions of P5PA-4I NPs, which were also structurally characterized by chemometric-assisted Fourier transform infrared spectroscopy (FTIR). Potentiometric titrations allowed us to estimate the milliequivalents of PA and basic nitrogen atoms present in NPs. P5PA-4I NPs afforded dispersions in water with excellent buffer capacity, essential to escape lysosomal degradation and promote long residence time inside cells. They were chemically stable in an aqueous medium for at least 40 days, while in dynamic light scattering (DLS) analyses, P5PA-4I showed a mean hydrodynamic diameter of 541 nm, small polydispersity (0.194), and low positive zeta potentials (+8.39 mV), assuring low haemolytic toxicity. Biological experiments on NB cells, demonstrated that P5PA-4I NPs induced ROS-dependent cytotoxic effects significantly higher than those of pristine 4I, showing a major efficacy compared to ETO in reducing cell viability in HTLA-ER cells. Collectively, this 4I-based nano-formulation could represent a new promising macromolecular platform to develop a new delivery system able to increase the cytotoxicity of the anticancer drugs.
Insights
This study developed novel nanoparticles carrying the imidazo-pyrazole compound 4I to treat drug-resistant neuroblastoma. The P5PA-4I nanoparticles significantly enhanced 4I
Area of Science:
- Nanomedicine
- Cancer Research
- Drug Delivery
Background:
- Neuroblastoma (NB) is a childhood cancer with limited treatment options due to drug resistance.
- Etoposide (ETO) is a common NB drug, but resistance diminishes its efficacy.
- Novel therapeutic strategies are needed to overcome chemoresistance in NB.
Purpose of the Study:
- To investigate the potential of synthesized imidazo-pyrazoles (IMPs) 4G and 4I against ETO-sensitive and ETO-resistant NB cells.
- To develop and characterize 4I-loaded nanoparticles (P5PA-4I NPs) to enhance the anti-cancer activity of 4I.
- To evaluate the efficacy of P5PA-4I NPs in overcoming chemoresistance in NB.
Main Methods:
- Synthesis and evaluation of IMPs 4G and 4I on NB cell lines.
- Development of 4I-loaded nanoparticles using palmitic acid (PA) and polystyrene (P5) via oil-in-water emulsification.
- Characterization of P5PA-4I NPs using microscopy, FTIR, potentiometric titrations, and DLS.
- Assessment of NP stability, buffer capacity, and haemolytic toxicity.
- Evaluation of NP-induced cytotoxicity and ROS generation in NB cells.
Main Results:
- Compound 4I showed promising activity against ETO-resistant NB cells, with lower IC50 values than ETO.
- P5PA-4I NPs were successfully synthesized with high drug loading (21%) and encapsulation efficiency (97%).
- P5PA-4I NPs exhibited excellent stability, buffer capacity, and low haemolytic toxicity.
- The nanoparticles demonstrated significantly higher ROS-dependent cytotoxicity compared to pristine 4I, outperforming ETO in reducing HTLA-ER cell viability.
Conclusions:
- The synthesized imidazo-pyrazole 4I is a promising candidate for treating chemoresistant neuroblastoma.
- The developed P5PA-4I nanoparticle formulation effectively enhances the delivery and cytotoxicity of 4I.
- This nano-formulation represents a potential macromolecular platform for developing advanced drug delivery systems against chemoresistant cancers.
