The simultaneous delivery of paclitaxel and Herceptin® using solid lipid nanoparticles: In vitro evaluation

HDL-Chitosan Nanoparticles for siRNA Delivery as an SR-B1 Receptor Targeted System

AIMS

High-Density Lipoprotein (HDL) is a complex structure unique to the human body. ApoA-1 protein is a significant structural/functional protein of HDL and provides a natural interaction with the SR-B1 receptors on the cell membrane. The overexpression of the SR-B1 receptor in the membrane of malignant cells suggests that targeting cancer cells can be possible using HDL. The objective of this study was to prepare HDL-conjugated chitosan nanoparticles containing a genetic material that can be used for liver cancer.

METHODS

HDL used in the preparation of the formulations have been obtained by isolating from blood samples taken from healthy volunteers. Bcl-2 siRNA inhibiting BCL-2 oncogene was selected as the genetic material. Chitosan nanoparticles were prepared using the ionic gelation method utilizing low molecular weight chitosan. Physicochemical properties of formulations, transfection efficacy, and cytotoxicity of them on 3T3 and HepG2 cell lines were examined.

RESULTS

The average diameters of the selected formulations were below 250 nm with a positive zeta potential value between +36 ± 0.1 and +34 ± 0.5 mV. All formulations protected Bcl-2 siRNA from enzymatic degradation in the presence of serum. Cellular uptake ratios of particles by HepG2 cells were found to be between 76% and 98%. HDL/chitosan nanoparticles/Bcl-2 siRNA complex was found to be more toxic when compared to chitosan nanoparticles/Bcl-2 siRNA complex and naked Bcl-2 siRNA.

CONCLUSION

According to attained results, the HDL-conjugated chitosan nanoparticles can bring advantages for targeted siRNA delivery to malignant cells that overexpress SR-B1 receptors, such as HepG2.

Progress and Principle of Drug Nanocrystals for Tumor Targeted Delivery

Drugs are referred to as drug nanocrystals when they exist as nanoscale crystal structures. This kind of nanocarrier has been widely utilized to increase the solubility and absorption for poorly aqueous soluble drugs after oral administration, or prolong the drug circulation when intravenous administration. The systemic cytotoxicity caused by antitumor drugs usually come from the nonspecific drug distribution. To solve the disadvantage of poor targetability, drug nanocrystals for tumor targeted delivery have been developed in recent years. In this review, the targeting mechanisms of various surface modified drug nanocrystals are introduced with the focus on passive targeting, active targeting and stimuli-responsive targeting in details. Function and application of common surface modified materials are also discussed.

Monoclonal Antibodies Carried in Drug Delivery Nanosystems as a Strategy for Cancer Treatment

Monoclonal antibodies carried in nanosystems have been extensively studied and reported as a promising tool for the treatment of various types of cancers. Monoclonal antibodies have great advantages for the treatment of cancer because their protein structure can bind to the target tissue; however, it has some challenges such as denaturation following heat exposure and extreme values of pH, temperature and solvents, the ability to undergo hydrolysis, oxidation and deamination and the formation of non-native aggregates, which compromise drug stability to a large extent. In addition to these characteristics, they suffer rapid elimination when in the blood, which results in a short half-life and the production of neutralizing antibodies, rendering the doses ineffective. These challenges are overcome with encapsulation in nanosystems (liposomes, polymer nanoparticles, cyclodextrins, solid lipid nanoparticles, nanostructured lipid carriers, dendrimers and micelles) due to the characteristics of improving solubility, permeability, and selectivity only with tumor tissue; with that, there is a decrease in side effects beyond controlled release, which is critical to improving the therapeutic efficacy of cancer treatment. The article was divided into different types of nanosystems, with a description of their definitions and applications in various types of cancers. Therefore, this review summarizes the use of monoclonal antibodies encapsulated in nanosystems and the description of clinical studies with biosimilars. Biosimilars are defined as products that are similar to monoclonal antibodies which are produced when the patent for the monoclonal antibodies expires.

Biologicals to direct nanotherapeutics towards HER2-positive breast cancers

HER2-positive breast cancer, an aggressive cancer, is treated with combinations of conventional anticancer drugs viz., cytotoxic drugs, nibs, and mAbs. Major limitations associated with this therapy are patient non-compliance due to the adverse drug reactions and rapid development of resistance by the HER2-positive malignant cells. While the former is addressed by the nano-formulations of the anticancer-drugs to some extent, the latter is still at large. This is because the nanocarriers of the anticancer drugs, by and large, lack the target specificity and selectivity. Thus, nowadays, to overcome these problems, various safe and efficacious biological agents are being used to direct the nanotherapeutics towards the HER2-positive breast cancers. The present review describes the potentials of such biological agents.

Dihydroartemisinin-Loaded Magnetic Nanoparticles for Enhanced Chemodynamic Therapy

Recently, chemodynamic therapy (CDT) has represented a new approach for cancer treatment with low toxicity and side effects. Nonetheless, it has been a challenge to improve the therapeutic effect through increasing the amount of reactive oxygen species (ROS). Herein, we increased the amount of ROS agents in the Fenton-like reaction by loading dihydroartemisinin (DHA) which was an artemisinin (ART) derivative containing peroxide groups, into magnetic nanoparticles (MNP), thereby improving the therapeutic effect of CDT. Blank MNP were almost non-cytotoxic, whereas three MNP loading ART-based drugs, MNP-ART, MNP-DHA, and MNP-artesunate (MNP-AS), all showed significant killing effect on breast cancer cells (MCF-7 cells), in which MNP-DHA were the most potent. What's more, the MNP-DHA showed high toxicity to drug-resistant breast cancer cells (MCF-7/ADR cells), demonstrating its ability to overcome multidrug resistance (MDR). The study revealed that MNP could produce ferrous ions under the acidic condition of tumor microenvironment, which catalyzed DHA to produce large amounts of ROS, leading to cell death. Further experiments also showed that the MNP-DHA had significant inhibitory effect on another two aggressive breast cancer cell lines (MDA-MB-231 and MDA-MB-453 cells), which indicated that the great potential of MNP-DHA for the treatment of intractable breast cancers.