Understanding structure-activity relationships of pH-sensitive cationic lipids facilitates the rational identification of promising lipid nanoparticles for delivering siRNAs in vivo

Designing siRNA-conjugated plant oil-based nanoparticles for gene silencing and cancer therapy

In this study, the anticancer activities of two siRNA carriers were compared using a human lung adenocarcinoma epithelial cell line (A549). Firstly, poly(styrene)-graft-poly(linoleic acid) (PS-g-PLina) and poly(styrene)-graft-poly(linoleic acid)-graft-poly(ethylene glycol) (PS-g-PLina-g-PEG) graft copolymers were synthesized by free-radical polymerization. PS-PLina and PS-PLina-PEG nanoparticles (NPs) were prepared by solvent evaporation method and were then characterized. The size was found as 150 ± 10 nm for PS-PLina and 184 ± 6 nm for PS-PLina-PEG NPs. The NPs were functionalized with poly(l-lysine) (PLL) for c-myc siRNA conjugation. siRNA entrapment efficiencies were found in the range of 4-63% for PS-PLina-PLL and 6-42% for PS-PLina-PEG-PLL NPs. The short-term stability test was realised for 1 month. siRNA release profiles were also investigated. In vitro anticancer activity of siRNA-NPs was determined by MTT, flow cytometry, and fluorescence microscopy analyses. Obtained findings showed that both NPs systems were promising as siRNA delivery tool for lung cancer therapy.

Recent advances in the targeting of systemically administered non-viral gene delivery systems

Introduction: Systemically administered non-viral gene delivery systems face multiple biological barriers that decrease their efficiency. These systems are rapidly cleared from the circulation and sufficient concentrations do not accumulate in diseased tissues. A number of targeting strategies can be used to provide for sufficient accumulation in the desired tissues to achieve a therapeutic effect. Areas covered: We discuss recent advances in the targeting of non-viral gene delivery systems to different tissues after systemic administration. We compare passive and active targeting applied for tumor delivery and propose some strategies that can be used to overcome the drawbacks of each case. We also discuss targeting the liver and lungs as two particularly important organs in gene therapy. Expert opinion: There is currently no optimum non-viral gene delivery system for targeting genes to specific tissues. The dose delivered to tumor tissues using passive targeting is low and shows a high patient variation. Although active targeting can enhance binding to specific cells, only a few reports are available to support its value in vivo. The design of smart nanocarriers for promoting active targeting is urgently needed and targeting the endothelium is a promising strategy for gene delivery to tumors as well as other organs.

Oncoprotein Inhibitor Rigosertib Loaded in ApoE-Targeted Smart Polymersomes Reveals High Safety and Potency against Human Glioblastoma in Mice

The unbiased cytotoxicity and blood-brain barrier (BBB) impermeability render common chemotherapeutics nonviable for treating glioblastoma (GBM) patients. Although rigosertib (RGS), a RAS effector protein inhibitor, has shown low toxicity to healthy cells and high efficacy toward various cancer cells by inactivating PI3K-Akt, it hardly overcomes the BBB barricade. Here, we report that RGS loaded in apolipoprotein E derived peptide (ApoE)-targeted chimaeric polymersomes (ApoE-CP) is safe and highly potent against human GBM in vivo. ApoE-CP exhibited stable loading of RGS in its lumen, giving RGS nanoformulations (ApoE-CP-RGS) with a size of 60 nm and reduction-triggered drug release behavior. Notably, ApoE-CP-RGS induction markedly enhanced the G2/M cell cycle arrest and inhibitory effect in U-87 MG glioblastoma cells compared with the nontargeted CP-RGS and free RGS. The therapeutic outcomes in orthotopic U-87 MG GBM models demonstrated that ApoE-CP-RGS brought about effective GBM inhibition, greatly prolonged survival time, and depleted adverse effects. Rigosertib formulated in ApoE-targeted chimaeric polymersomes has emerged as a novel, highly specific, efficacious, and nontoxic treatment for glioblastoma.

Co-delivery of D-(KLAKLAK)2 Peptide and Chlorin e6 using a Liposomal Complex for Synergistic Cancer Therapy

Nanotechnology-based photo-chemo combination therapy has been extensively investigated to improve therapeutic outcomes in anticancer treatment. Specifically, with the help of a singlet oxygen generated by the photosensitizer, the endocytosed nanoparticles are allowed to escape from the endosomal compartment, which is currently an obstacle in nanotechnology-based anticancer therapy. In this study, a liposomal complex system (Lipo (Pep, Ce6)), composed of a chlorin e6-conjugated di-block copolymer (PEG-PLL(-g-Ce6)) and a D-(KLAKLAK)2 peptide loading liposome (Lipo (Pep)), was developed and evaluated for its anticancer activity. Due to the membrane lytic ability of the D-(KLAKLAK)2 peptide and the membrane disruptive effect of the singlet oxygen generated from chlorin e6, Lipo (Pep, Ce6) accelerated the disruption of the endosomal compartment, and exhibited strong synergistic anticancer activity in vitro. The prepared liposomal complex system could potentially maximize the efficacy of the nanotechnology-based photo-chemo combination therapy, and can be regarded as a novel, versatile strategy in advanced tumor therapy.

Cell Subtypes Within the Liver Microenvironment Differentially Interact with Lipid Nanoparticles

Introduction

Lipid nanoparticles (LNPs) tend to accumulate in the liver due to physiological factors. Whereas the biological mechanisms that promote LNP delivery to hepatocytes have been reported, the mechanisms that promote delivery to other cell types within the liver microenvironment are poorly understood. Single cell profiling studies have recently identified subsets of Kupffer cells and hepatic endothelial cells with distinct gene expression patterns and biological phenotypes; we hypothesized these subtypes would differentially interact with nanoparticles.

Methods

To test the hypothesis, we quantified nucleic acid (i) biodistribution and (ii) functional mRNA delivery within the liver microenvironment using two clinically relevant LNPs in vivo.

Results

We found that these LNPs distribute nucleic acids distribute to Kupffer cells and liver endothelial cells as efficiently as they distribute to hepatocytes, yet result in more functional mRNA delivery to endothelial cells. Additionally, we found these LNPs differentially accumulate in Kupffer and endothelial cell subsets.

Conclusions

These data suggest subsets of liver microenvironmental cells can differentially interact with nanoparticles in vivo, thereby altering LNP delivery. More generally, the data suggest that nucleic acid biodistribution is not sufficient to predict functional nucleic acid delivery in vivo.

Optimizing Advances in Nanoparticle Delivery for Cancer Immunotherapy

Cancer immunotherapy is one of the fastest growing and most promising fields in clinical oncology. T-cell checkpoint inhibitors are revolutionizing the management of advanced cancers including non-small cell lung cancer and melanoma. Unfortunately, many common cancers are not responsive to these drugs and resistance remains problematic. A growing number of novel cancer immunotherapies have been discovered but their clinical translation has been limited by shortcomings of conventional drug delivery. Immune signaling is tightly-regulated and often requires simultaneous or near-simultaneous activation of multiple signals in specific subpopulations of immune cells. Nucleic acid therapies, which require intact intracellular delivery, are among the most promising approaches to modulate the tumor microenvironment to a pro-immunogenic phenotype. Advanced nanomedicines can be precisely engineered to overcome many of these limitations and appear well-poised to enable the clinical translation of promising cancer immunotherapies.

Co-delivery of d-(KLAKLAK)2 peptide and doxorubicin using a pH-sensitive nanocarrier for synergistic anticancer treatment

Currently, one of the most important challenges in the development of nanotechnology-based anticancer treatments is the failure of nanoparticles to escape from the endo-lysosomal compartment.