Multifunctional drug nanocarriers formed by cRGD-conjugated βCD-PAMAM-PEG for targeted cancer therapy

Dendritic polymer prodrug-based unimolecular micelles for pH-responsive co-delivery of doxorubicin and camptothecin with synergistic controlled drug release effect

Combination chemotherapy has been recognized as a more powerful strategy for tumor treatment rather than the single chemotherapy. However, the interactive mechanism of the two hydrophobic chemotherapeutic drugs has not been explored by now. Aiming for a better synergistic effect, such interactive mechanism was investigated in the present work, by designing CPT@DOX-DPUTEA-PEG nanomedicine with encapsulated camptothecin (CPT) and conjugated doxorubicin (DOX). The synergistic controlled drug release effect was found for the two drugs loaded on the different sites of the dendritic polyurethane core. Synergism was achieved on the HepG2 cells with a combination index (CI) of 0.58 in the in vitro cellular experiments. The results demonstrated the promising application of the unimolecular micelles-based nanomedicine with independently loading of two hydrophobic chemotherapeutic drugs.

Physico-mechanical and ex vivo analysis of aloe-alginate hydrogels for cervical cancer treatment

A leading cancer diagnosis in women worldwide is cervical cancer, with current treatments all posing a risk of serious side effects. Less toxic, but effective treatments are sought after. Aloe vera ( barbadensis miller), known for its beneficial properties, has been studied for cancer treatment. While aloe gel has been shown to exhibit anti-cancer activity, it cannot form a hydrogel alone. Therefore, an interpenetrating network comprising alginate blended with aloe was examined as a cervical cancer treatment. We hypothesized the antioxidant properties of aloe gel would decrease cancer cell viability while the alginate hydrogel would improve mucoadhesion. We further hypothesized the antioxidant activity of aloe gel would induce cancer cell death at levels similar to common chemotherapeutics, and aimed to determine if these chemotherapeutic behaviors are constructive or destructive. Material and adhesive properties, drug encapsulation, and cancer cell viability were investigated and validated. The effect of aloe-alginate hydrogels on cervical cancer cell viability was not significantly different compared to aloe-blends containing doxorubicin (DOX), indicating that the aloe alone decreased cancer cell viability rendering the additional cytotoxic therapeutic not impactful as an adjuvant therapy. This study provides insight into the potential of natural biopolymers for treating cervical cancer without systemic toxic compounds.

Facile Synthesis of a Redox-Responsive Hyperbranched Polymer Prodrug as a Unimolecular Micelle for the Tumor-Selective Drug Delivery

Demicellization of the self-assembled multimolecular micelles upon dilution restricts their application as drug delivery systems (DDSs) for tumor treatment. Here, a redox-responsive hyperbranched polymer prodrug (HBPP) was designed with a high drug content of 62.0% as a unimolecular micelle for the tumor-selective drug delivery, via the facile self-condensing vinyl polymerization (SCVP) of redox-responsive doxorubicin-based prodrug monomer MA-SS-DOX and poly(ethylene glycol) methacrylate (PEGMA) with p-chloromethylstyrene (CMS) as an inimer. The unimolecular micelle could be easily obtained with a hydrodynamic diameter of 122 nm, showing excellent GSH-triggered drug release performance with a cumulative release of 60.9% within 85 h but a low premature drug leakage of 3.2%. The unimolecular micelle exhibited selective tumor growth inhibition on HepG2 cells but no obvious cytotoxicity on L02 cells.

A versatile modular preparation strategy for targeted drug delivery systems against multidrug-resistant cancer cells

Nanotechnology is widely used in targeted drug delivery, but different drug delivery systems need to 're-determine' different synthesis schemes, which greatly limits the further expansion of targeted nanomedicine applications. In this study, we propose a facile and versatile modular stacking strategy to fabricate targeted drug delivery systems to enable tailored designs for patient-specific therapeutic responses. The systems were constructed by a pH-sensitive prodrug module and a mitochondrial targeting module via self-assembly. Using this modular strategy, we successfully prepared two targeting nano-drug delivery systems, TPP-DOX and PK-DOX, where the mitochondrial targeting molecules were triphenylphosphonium (TPP) and 1-(2-Chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide (PK11195), respectively. Confocal laser microscopy and flow cytometry tests revealed that TPP-DOX and PK-DOX exhibited high mitochondria targeting capability and greatly improved the drug retention in drug-resistant cells. The antitumor activity tests showed that the IC50 values of TPP-DOX and PK-DOX in MCF-7/ADR cells were 2.5- and 8.2-fold lower than that of free DOX, respectively. These results indicated that PK was more effective than TPP. The studies on their therapeutic effects on human breast cancer resistant cells verified the feasibility of the modular approach, indicated that the two modular targeted drug delivery systems: (1) retain the drug toxicity and cell-killing effect of the prodrug module, (2) have precise targeting capabilities due to mitochondrial targeting module, (3) enhance drug uptake, reduce drug efflux and reverse the multidrug resistance effect to a certain extent. The results show that modular stacking is a practical, effective and versatile method for preparing targeting drugs with broad application prospects. This study provides an easy approach on preparing customizable targeted drug delivery systems to improve precision therapies.

RGD engineered dendrimer nanotherapeutic as an emerging targeted approach in cancer therapy

A bird's eye view is now demanded in the area of cancer research to suppress the suffering of cancer patient and mediate the lack of treatment related to chemotherapy. Chemotherapy is always preferred over surgery or radiation therapy, but they never met the patient's demand of safe medication. Targeted therapy has now been in research that could hinder the unnecessary effect of drug on normal cells but could affect the tumor cells in much efficient manner. Angiogenesis is process involved in development of new blood vessel that nourishes tumor growth. Integrin receptors are over expressed on cancer cells that play vital role in angiogenesis for growth and metastasis of tumor cell. A delivery of RGD based peptide to integrin targeted site could help in its successful binding and liberation of drug in tumor vasculature. Dendrimers, in addition to its excellent pharmacokinetic properties also helps to carry targeting ligand to site of tumor by successfully conjugating with them. The aim of this review is to bring light upon the role of integrin in cancer progression, interaction of RGD to integrin receptor and more importantly the RGD-dendrimer based targeted therapy for the treatment of various cancers.

An oligopeptide/aptamer-conjugated dendrimer-based nanocarrier for dual-targeting delivery to bone

Bone targeting is one of the most potentially valuable therapeutic methods for medically treating bone diseases, such as osteoarthritis, osteoporosis, nonunion bone defects, bone cancer, and myeloma-related bone disease, but its efficacy remains a challenge due to unfavorable bone biodistribution, off-target effects, and the lack of cell specificity. To address these problems, we synthesized a new dual-targeting nanocarrier for delivery to bone by covalently modifying the G4.0 PAMAM dendrimer with the C11 peptide and the CH6 aptamer (CH6-PAMAM-C11). The molecular structure was confirmed using ¹H-NMR and FT-IR spectroscopy. CLSM results showed that the novel nanocarrier could successfully accumulate in the targeted cells, mineralized areas and tissues. DLS and TEM demonstrated that CH6-PAMAM-C11 was approximately 40-50 nm in diameter. In vitro targeting experiments confirmed that the C11 ligand had a high affinity for HAP, while the CH6 aptamer had a high affinity for osteoblasts. The in vivo biodistribution analysis showed that CH6-PAMAM-C11 could rapidly accumulate in bone within 4 h and 12 h and then deliver drugs to sites of osteoblast activity. The components of CH6-PAMAM-C11 were well excreted via the kidneys. The accumulation of many more CH6-PAMAM-C11 dual-targeting nanocarriers than single-targeting nanocarriers was observed in the periosteal layer of the rat skull, along with aggregation at sites of osteoblast activity. All of these results indicate that CH6-PAMAM-C11 may be a promising nanocarrier for the delivery of drugs to bone, particularly for the treatment of osteoporosis, and our research strategy may serve as a reference for research in targeted drug, small molecule drug and nucleic acid delivery.

Black phosphorus nanosheets-based platform for targeted chemo-photothermal synergistic cancer therapy

As a new member of two-dimensional (2D) nanomaterials, black phosphorus (BP) has been considered as efficient photothermal therapy (PTT) agents owing to its excellent photothermal efficiency and biodegradability. Herein, a multifunctional nanoplatform based on black phosphorus nanosheets (BP NSs) was developed for chemo-photothermal synergistic cancer therapy. The BP NSs were successfully prepared by a liquid exfoliation technique. Doxorubicin (DOX), as a model drug, was loaded into the cavity of poly (amidoamine) (PAMAM) dendrimer using thin film hydration method. Then, PAMAM@DOX was coated on the surface of BP NSs using an electrostatic adsorption method that combined bath sonication with magnetic stirring. Hyaluronic acid (HA) was also modified onto the BP NS-PAMAM@DOX through electrostatic adsorption. PAMAM and HA layer could effectively isolate BP NSs from water and air to improve physiological stability. BP NSs and BP NS-PAMAM@DOX-HA were characterized by particle size, zeta potential, morphology, UV-vis-NIR absorption spectra, stability, photothermal performance and photothermal stability. This nanosystem exhibited a good pH and near infrared (NIR) dual-responsive drug release property. In addition, the obtained BP NS-PAMAM@D OX-HA nanocomposites possessed excellent PTT efficiency both in vitro and in vivo. The in vitro cell experiments suggested that the targeted BP NS-PAMAM@DOX-HA presented greater cytotoxicity and higher cellular uptake efficiency. Tumor xenograft model was established in BALB/C mice. The therapeutic effect of BP NS-PAMAM@DOX-HA was further augmented under 808 nm laser irradiation, displaying superior antitumor effect in comparison with chemotherapy or PTT alone. Such a biodegradable BP NS-based platform provide new insights for the rational design of PTT-based combinational cancer therapy.

A biocompatible poly(amidoamine) (PAMAM) dendrimer octa-substituted with α-cyclodextrin towards the controlled release of doxorubicin hydrochloride from its ferrocenyl prodrug

Facile and efficient methods for the synthesis of the first poly(aminodamine) PAMAM G1.0 dendrimer octa-substituted with α-cyclodextrin and a novel ferrocenyl prodrug of doxorubicin hydrochloride are developed. This vector is non-toxic and can bind the designed ferrocenyl prodrug. It also shows a controlled drug release profile and high cytotoxicity against breast cancer cells (MCF-7), as elucidated by the in vitro biological studies performed with an innovative cell-on-a-chip microfluidic system.

A controlled release of doxorubicin hydrochloride from a novel nanoconjugate comprising PAMAM dendrimer octa-substituted with α-cyclodextrin and ferrocenyl prodrug is presented.

PEGylated trimethylchitosan emulsomes conjugated to octreotide for targeted delivery of sorafenib to hepatocellular carcinoma cells of HepG2

The current study aimed to develop PEGylated trimethyl chitosan (TMC) coated emulsomes (EMs) conjugated with octreotide for targeted delivery of sorafenib to hepatocellular carcinoma cells (HCC) of HepG2. Sorafenib loaded TMC coated EMs were prepared by the emulsion evaporation method and characterized concerning particle size, zeta potential, drug encapsulation efficiency, and in vitro drug release. Synthesized EMs were then conjugated to octreotide. The cytotoxicity of the targeted and non-targeted EMs was determined by cellular uptake and MTT assay on HepG2 cell. Cell cycle assay was also studied using flow cytometry. The results showed the optimized EMs had the particle size of 127 nm, zeta potential of -5.41 mV, loading efficiency of 95%, and drug release efficiency of 62% within 52 h. Octreotide was attached efficiently to the surface of EMs as much as 71%. MTT assay and cellular uptake studies showed that targeted EMs had more cytotoxicity than free sorafenib and non-targeted EMs. Cell cycle analyses revealed that there was a significant more accumulation of targeted EMs treated HepG2 cells in the G1 phase than free sorafenib and non-targeted EMs. The results indicate that designed EMs may be promising for the treatment of hepatocellular carcinoma.

Phenylboronic acid-functionalized polyamidoamine-mediated miR-34a delivery for the treatment of gastric cancer

In the present research, a tumor-targeted gene carrier, PPP, was constructed through the modification of phenylboronic acid onto the surface of a polyamidoamine dendrimer, and then miR-34a delivery was employed as a model to evaluate its anti-tumor efficacy.

Cyclodextrin-based delivery systems for cancer treatment

Cyclodextrins, one of safe excipients, are able to form host-guest complexes with fitted molecules given the unique nature imparted by their structure in result of a number of pharmaceutical applications. On the other hand, targeted or responsive materials are appealing therapeutic platforms for the development of next-generation precision medications. Meanwhile, cyclodextrin-based polymers or assemblies can condense DNA and RNA in result to be used as genetic therapeutic agents. Armed with a better understanding of various pharmaceutical mechanisms, especially for cancer treatment, researchers have made lots of works about cyclodextrin-based drug delivery systems in materials chemistry and pharmaceutical science. This Review highlights recent advances in cyclodextrin-based delivery systems for cancer treatment capable of targeting or responding to the physiological environment. Key design principles, challenges and future directions, including clinical translation, of cyclodextrin-based delivery systems are also discussed.

RGD-modified polymer and liposome nanovehicles: Recent research progress for drug delivery in cancer therapeutics

Over the past few decades, as the demand for cancer treatment has increased, more rational treatment options (considering size, mode of administration, biocompatibility, efficacy, etc.) and plenty of specifically active targeted nanovehicles have been developed. Integrin receptors targeting are one of the most frequently used approaches because of its highly expressed in cancer cells. In particular, the arginine-glycine-aspartic acid (RGD) peptide and its derivatives have been widely used as ligands for integrin to increase direct targeting capabilies. Polymers as well as liposomes are commonly used as nanovehicles for drug delivery. A variety of work is focused on the RGD-modified polymer and liposome nanovehicles for cancer therapeutics. The goal of this article is to review the published literature in recent years concerning the RGD-modified liposome and polymer nanovehicles to highlight its successful designs for improving cancer therapy and discuss the current challenges as well as the possible development prospects.

A novel RGDyC/PEG co-modified PAMAM dendrimer-loaded arsenic trioxide of glioma targeting delivery system

Background

The Traditional Chinese Medicine, arsenic trioxide (ATO, As₂O₃) could inhibit growth and induce apoptosis in a variety of solid tumor cells, but it is severely limited in the treatment of glioma due to its poor BBB penetration and nonspecifcity distribution in vivo.

Purpose

The objective of this study was encapsulating ATO in the modified PAMAM den-drimers to solve the problem that the poor antitumor effect of ATO to glioma, which provide a novel angle for the study of glioma treatment.

Methods

The targeting drug carrier (RGDyC-mPEG-PAMAM) was synthesized based on Arg-Gly-Asp (RGDyC) and αvβ3 integrin targeting ligand, and conjugated to PEGylated fifth generation polyamidoamine dendrimer (mPEG-PAMAM). It was characterized by nuclear magnetic resonance, fourier transform infrared spectra, Nano-particle size-zeta potential analyzer,etc. The in vitro release characteristics were studied by dialysis bag method. MTT assay was used to investigate the cytotoxicity of carriers and the antitumor effect of ATO formulation. In vitro blood-brain barrier (BBB) and C6 cell co-culture models were established to investigate the inhibitory effect of different ATO formulation after transporting across BBB. Pharmacokinetic and antitumor efficacy studies were investigated in an orthotopic murine model of C6 glioma.

Results

The prepared RGDyC-mPEG-PAMAM was characterized for spherical dendrites, comparable size (21.60±6.81 nm), and zeta potential (5.36±0.22 mV). In vitro release showed that more ATO was released from RGDyC-mPEG-PAMAM/ATO (79.5%) at pH 5.5 than that of pH 7.4, during 48 hours. The cytotoxicity of PEG-modified carriers was lower than that of the naked PAMAM on both human brain microvascular endothelial cells and C6 cells. In in vitro BBB model, modification of RGDyC heightened the cytotoxicity of ATO loaded on PAMAM, due to an increased uptake by C6 cells. The results of cell cycle and apoptosis analysis revealed that RGDyC-mPEG-PAMAM/ATO arrested the cell cycle in G2-M and exhibited threefold increase in percentage of apoptosis to that in the PEG-PAMAM/ATO group. Compared with ATO-sol group, both RGDyC-mPEG-PAMAM/ATO and mPEG-PAMAM/ATO groups prolonged the half-life time, increased area under the curve, and improved antitumor effect, significantly. While the tumor volume inhibitory of RGDyC-mPEG-PAMAM/ATO was 61.46±12.26%, it was approximately fourfold higher than the ATO-sol group, and twofold to the mPEG-PAMAM/ATO group.

Conclusion

In this report, RGDyC-mPEG-PAMAM could enhance the antitumor of ATO to glioma, it provides a desirable strategy for targeted therapy of glioma.

Advancement in Photothermal Effect of Carbon Nanotubes by Grafting of Poly(amidoamine) and Deposition of CdS Nanocrystallites

A robust, near-infrared (NIR) active photothermal agent, CNTs-PAMAM/G4-CdS, is designed by covalent grafting of fourth generation poly(amidoamine) (PAMAM) to carbon nanotubes (CNTs) and successive deposition of cadmium sulfide (CdS) nanocrystallites. The systematic advancement in photothermal effect of CNTs was achieved by grafting of first, second, third, and fourth generation PAMAM through the repeated process of Michael's addition. The subsequent deposition of CdS nanocrystallites over fourth generation PAMAM grafted CNTs has further improved the photothermal effect (PTE) of CNTs. The photothermal effect of CNTs-PAMAM/G4-CdS was accessed by illuminating with 980 nm NIR laser. During measurement of PTE, maximum temperature attained by CNTs-PAMAM/G4-CdS was 64.1 °C which far exceeds the survival temperature of cancer cells. The photothermal conversion efficiency estimated for CNTs-PAMAM/G4-CdS was 32%, which is higher than the value reported for popular gold and copper based photothermal agents. Apart from its outstanding photothermal effect, CNTs-PAMAM/G4-CdS possessed excellence in both antiphoto-bleaching and antiphoto-corrosiveness.

Arginylglycylaspartic Acid-Surface-Functionalized Doxorubicin-Loaded Lipid-Core Nanocapsules as a Strategy to Target Alpha(V) Beta(3) Integrin Expressed on Tumor Cells

Doxorubicin (Dox) clinical use is limited by dose-related cardiomyopathy, becoming more prevalent with increasing cumulative doses. Previously, we developed Dox-loaded lipid-core nanocapsules (Dox-LNC) and, in this study, we hypothesized that self-assembling and interfacial reactions could be used to obtain arginylglycylaspartic acid (RGD)-surface-functionalized-Dox-LNC, which could target tumoral cells overexpressing αvβ3 integrin. Human breast adenocarcinoma cell line (MCF-7) and human glioblastoma astrocytoma (U87MG) expressing different levels of αvβ3 integrin were studied. RGD-functionalized Dox-LNC were prepared with Dox at 100 and 500 mg·mL-1 (RGD-MCMN (Dox100) and RGD-MCMN (Dox500)). Blank formulation (RGD-MCMN) had z-average diameter of 162 ± 6 nm, polydispersity index of 0.11 ± 0.04, zeta potential of +13.2 ± 1.9 mV and (6.2 ± 1.1) × 1011 particles mL-1, while RGD-MCMN (Dox100) and RGD-MCMN (Dox500) showed respectively 146 ± 20 and 215 ± 25 nm, 0.10 ± 0.01 and 0.09 ± 0.03, +13.8 ± 2.3 and +16.4 ± 1.5 mV and (6.9 ± 0.6) × 1011 and (6.1 ± 1.0) × 1011 particles mL-1. RGD complexation was 7.73 × 10⁴ molecules per nanocapsule and Dox loading were 1.51 × 10⁴ and 7.64 × 10⁴ molecules per nanocapsule, respectively. RGD-functionalized nanocapsules had an improved uptake capacity by U87MG cells. Pareto chart showed that the cell viability was mainly affected by the Dox concentration and the period of treatment in both MCF-7 and U87MG. The influence of RGD-functionalization on cell viability was a determinant factor exclusively to U87MG.

Anticancer Therapeutic Alginate-Based Tissue Sealants for Lung Repair

Injury to the connective tissue that lines the lung, the pleura, or the lung itself can occur from many causes including trauma or surgery, as well as lung diseases or cancers. To address current limitations for patching lung injuries, to stop air or fluid leaks, an adherent hydrogel sealant patch system was developed, based on methacrylated alginate (AMA) and AMA dialdehyde (AMA-DA) blends, which is capable of sealing damaged tissues and sustaining physiological pressures. Methacrylation of alginate hydroxyl groups rendered the polysaccharide capable of photo-cross-linking when mixed with an eosin Y-based photoinitiator system and exposed to visible green light. Oxidation of alginate yields functional aldehyde groups capable of imine bond formation with proteins found in many tissues. The alginate-based patch system was rigorously tested on a custom burst pressure testing device. Blending of nonoxidized material with oxidized (aldehyde modified) alginates yielded patches with improved burst pressure performance and decreased delamination as compared with pure AMA. Human mesothelial cell (MeT-5A) viability and cytotoxicity were retained when cultured with the hydrogel patches. The release and bioactivity of doxorubicin-encapsulated submicrospheres enabled the fabrication of drug-eluting adhesive patches and were effective in decreasing human lung cancer cell (A549) viability.

PEGylated PAMAM dendrimers: Enhancing efficacy and mitigating toxicity for effective anticancer drug and gene delivery

Poly(amidoamine) dendrimers (PAMAM) are well-defined, highly branched, nanoscale macromolecules with numerous active amine groups on the surface. PAMAM dendrimer can enhance the solubility of hydrophobic drugs, and with numerous reactive groups on the surface PAMAM dendrimer can be engineered with various functional groups for specific targeting ability. However, in physiological conditions, these amine groups are toxic to cells and limit the application of PAMAM. In the recent years, polyethylene glycol (PEG) conjugation has been the most widely used approach to reduce the toxicity of the active group on dendrimer surface. PEG molecules are known to be inert, non-immunogenic, and non-antigenic with a significant water solubility. PEGylated PAMAM-mediated delivery could not only overcome the limitations of dendrimer such as drug leakage, immunogenicity, hemolytic toxicity, systemic cytotoxicity but they also have the ability to enhance the solubilization of hydrophobic drugs and facilitates the potential for DNA transfection, siRNA delivery and tumor targeting. This review focuses on the recent developments on the application and influence of PEGylation on various biopharmaceutical properties of PAMAM dendrimers.

STATEMENT OF SIGNIFICANCE

It is well established that dendrimers have demonstrated promising potentials for drug delivery. However, the inherent toxicity poses challenges for its clinical translation. In this regard, PEGylation has helped mitigate some of the toxicity concerns of dendrimers and have paved the way forward for testing its translational potentials. The review is a collection of articles demonstrating the utility of PEGylation of the most studied PAMAM dendrimers. To our knowledge, this is a first such attempt to draw reader's attention, specifically, towards PEGylated PAMAM dendrimers.