Polyamidoamine-based nanovector for the efficient delivery of methotrexate to U87 glioma cells

Polyamidoamine Dendrimers: Brain-Targeted Drug Delivery Systems in Glioma Therapy

Glioma is the most common primary intracranial tumor, which is formed by the malignant transformation of glial cells in the brain and spinal cord. It has the characteristics of high incidence, high recurrence rate, high mortality and low cure rate. The treatments for glioma include surgical removal, chemotherapy and radiotherapy. Due to the obstruction of the biological barrier of brain tissue, it is difficult to achieve the desired therapeutic effects. To address the limitations imposed by the brain's natural barriers and enhance the treatment efficacy, researchers have effectively used brain-targeted drug delivery systems (DDSs) in glioma therapy. Polyamidoamine (PAMAM) dendrimers, as branched macromolecular architectures, represent promising candidates for studies in glioma therapy. This review focuses on PAMAM-based DDSs in the treatment of glioma, highlighting their physicochemical characteristics, structural properties as well as an overview of the toxicity and safety profiles.

Recent advances in multifunctional dendrimer-based complexes for cancer treatment

The application of nanotechnology in biological and medical fields have resulted in the creation of new devices, supramolecular systems, structures, complexes, and composites. Dendrimers are relatively new nanotechnological polymers with unique features; they are globular in shape, with a topological structure formed by monomeric subunit branches diverging to the sides from the central nucleus. This review analyzes the main features of dendrimers and their applications in biology and medicine regarding cancer treatment. Dendrimers have applications that include drug and gene carriers, antioxidant agents, imaging agents, and adjuvants, but importantly, dendrimers can create complex nanosized constructions that combine features such as drug/gene carriers and imaging agents. Dendrimer-based nanosystems include different metals that enhance oxidative stress, polyethylene glycol to provide biosafety, an imaging agent (a fluorescent, radioactive, magnetic resonance imaging probe), a drug or/and nucleic acid that provides a single or dual action on cells or tissues. One of major benefit of dendrimers is their easy release from the body (in contrast to metal nanoparticles, fullerenes, and carbon nanotubes), allowing the creation of biosafe constructions. Some dendrimers are already clinically approved and are being used as drugs, but many nanocomplexes are currently being studied for clinical practice. In summary, dendrimers are very useful tool in the creation of complex nanoconstructions for personalized nanomedicine. This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Cell internalization kinetics and surface charge accessibility of surface-modified PAMAM dendrimers

Surface-modified PAMAM dendrimers have important applications in drug delivery, yet a gap remains about the role that surface functionalization plays on their cell internalization capacity. We examined the cell internalization kinetics of PAMAM dendrimers that were surface-modified with acetyl, folate and poly(ethylene glycol), as model functional groups differing in size, charge, and chemical functionality. Dendrimers with 25% functionalization were internalized by HEK cells, but with slower rates and lower maximum uptakes than the native dendrimer between 1-6 h of incubation. Dendrimers with 50% functionalization exhibited negligible internalization capacities at all incubation times. Molecular dynamics simulations revealed that the solvent accessibility of the cationic surface charges is a key factor affecting cell internalization, unlike the total charge, functionality or size of surface-modified PAMAM dendrimers. These findings provide valuable insights to assist the design of PAMAM-based systems for drug delivery applications.

Functionalized PAMAM-Based Nanoformulation for Targeted Delivery of 5-Fluorouracil in Hepatocellular Carcinoma

BACKGROUND

Efficacy of a traditional anticancer drug is challenged by adverse effects of the drug including its nonspecific bio-distribution, short half-life and side effects. Dendrimer-based targeted drug delivery sysytem has been considered as a promising strategy to increase targeting ability and reduce adverse effects of anti-cancer drugs.

OBJECTIVE

This study analyzed the feasibility whether the anticancer drug 5-fluorouracil (5-FU) could be delivered by functionalized fifth-poly(amidoamine) (PAMAM) with the peptide WP05 and the acetic anhydride to the liver cancer cells, reducing toxicity of the PAMAM and improving the targeting property of 5-FU during delivery.

METHODS

The functionalized PAMAM-based nanoformulation (WP05-G5.0NHAC-FUA) was fabricated through an amide condensation reaction to improve therapeutic efficacy of 5-Fluorouracil (5-FU) in hepatocellular carcinoma (HCC). The physicochemical structure, particle size, zeta potential, stability and in vitro release characteristics of WP05-G5.0NHAC-FUA were evaluated. In addition, the targeting, biocompatibility, anti-proliferation and anti-migration of WP05-G5.0NHAC-FUA were investigated. The anti-tumor effect of WP05-G5.0NHAC-FUA in vivo was evaluated by constructing xenograft tumor models of hunman hepatoma cells (Bel-7402) implanted in nude mice.

RESULTS

The resultant WP05-G5.0NHAC-FUA displayed spherical-like nanoparticles with the size of 174.20 ± 3.59 nm. Zeta potential and the drug loading of WP05-G5.0NHAC-FUA were 5.62 ± 0.41mV and 28.67 ± 1.25 %, respectively. Notably, the optimized 5-FU-loaded formulation showed greater cytotoxicity with an IC50 of 30.80 ±4.04 μg/mL than free 5-FU (114.93 ±1.43 μg/mL) in Bel-7402 cancer liver cells, but a significantly reduced side effect relative to free 5-FU in L02 normal liver cells. In vivo animal study further confirmed efficient tumor accumulation and enhanced therapeutic efficiency.

CONCLUSION

The developed nanoformulation is a promising platform for the targeting delivery of 5-FU and provides a promising solution for improving the efficacy of hepatocellular carcinoma chemotherapy.

Polyamidoamine dendrimers of the third generation–chlorin e6 nanoconjugates: Nontoxic hybrid polymers with photodynamic activity

Dendrimer‐based nanoconjugates play a key role as functional polymers for biomedical applications. In this work, the one‐pot conjugation of polyamidoamine dendrimers of the third generation (PAMAM‐G3) with the photosensitizer chlorin e6 (Ce6) is presented using 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC) and N‐hydroxysuccinimide (NHS) to mediate the synthesis, resulting in a 9% substitution degree according to nuclear magnetic resonance data. The PAMAM‐G3‐Ce6 nanoconjugate exhibits reduced cytotoxicity compared with the native dendrimer and efficient photodynamic activity against HeLa cancer cells after 1 h of incubation with a 100 μmol L−1 solution and 3 min of irradiation with red light‐emitting diode light (628 nm, 259 W m−2). Molecular dynamics simulations confirm that the PAMAM‐G3‐Ce6 system adopts a spherical structure and retains the internal dendritic cavities that enable drug encapsulation, which is relevant for the potential use of these hybrid polymers in combined chemo/photodynamic therapy.