Novel Fluorinated Spermine and Small Molecule PEI to Deliver Anti-PD-L1 and Anti-VEGF siRNA for Highly Efficient Tumor Therapy

Making the negative positive - fluorination of indole as an efficient strategy to improve guanidinium-containing gene carriers

The balance between hydrophilic and hydrophobic components plays an important role in polymeric delivery of nucleic acids. Besides using hydrophobic moieties in the polymer design, fluorination is a promising method to increase the hydrophobicity of polymers. To systematically investigate this effect, N-(2-(1H-indol-3-yl)ethyl)methacrylamide and three fluorinated analogues have been synthesized and copolymerized with 3-guanidinopropyl methacrylamide and 2-hydroxypropyl methacrylamide via an aqueous reversible addition-fragmentation chain transfer (aRAFT) polymerization. A library of eight terpolymers with 5 to 23 mol% of an indole analogue and molar mass about 20 kg mol-1 showed comparably strong DNA binding starting at N/P 2 and formed polyplexes with hydrodynamic diameters around 100 nm. Additionally, no negative impact on biocompatibility was observed. Heparin release studies showed increased DNA binding strength with higher amounts of hydrophobic moieties, while fluorination exhibited similar effects as increasing the indole content. This was also important for pDNA transfection efficiency, where an optimum for DNA binding strength was unveiled. The rapid release and the excessive binding of DNA were identified as factors that negatively impacted transfection efficiency, both influenced by the amount of indole moieties and fluorination. On the other hand, the right degree of hydrophobicity was able to increase the transfection efficiency of the modified polymer by more than threefold. These findings highlight the role of hydrophobic moieties in nucleic acid delivery and provide valuable insights for future polymer design, suggesting that the strategic incorporation of fluorinated monomers can effectively fine-tune DNA interactions.

Role of PD-1/PD-L1 signaling axis in oncogenesis and its targeting by bioactive natural compounds for cancer immunotherapy

Cancer is a global health problem and one of the leading causes of mortality. Immune checkpoint inhibitors have revolutionized the field of oncology, emerging as a powerful treatment strategy. A key pathway that has garnered considerable attention is programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1). The interaction between PD-L1 expressed on tumor cells and PD-1 reduces the innate immune response and thus compromises the capability of the body's immune system. Furthermore, it controls the phenotype and functionality of innate and adaptive immune components. A range of monoclonal antibodies, including avelumab, atezolizumab, camrelizumab, dostarlimab, durvalumab, sinitilimab, toripalimab, and zimberelimab, have been developed for targeting the interaction between PD-1 and PD-L1. These agents can induce a broad spectrum of autoimmune-like complications that may affect any organ system. Recent studies have focused on the effect of various natural compounds that inhibit immune checkpoints. This could contribute to the existing arsenal of anticancer drugs. Several bioactive natural agents have been shown to affect the PD-1/PD-L1 signaling axis, promoting tumor cell apoptosis, influencing cell proliferation, and eventually leading to tumor cell death and inhibiting cancer progression. However, there is a substantial knowledge gap regarding the role of different natural compounds targeting PD-1 in the context of cancer. Hence, this review aims to provide a common connection between PD-1/PD-L1 blockade and the anticancer effects of distinct natural molecules. Moreover, the primary focus will be on the underlying mechanism of action as well as the clinical efficacy of bioactive molecules. Current challenges along with the scope of future research directions targeting PD-1/PD-L1 interactions through natural substances are also discussed.

A Multifunctional Nanodrug Co-Delivering VEGF-siRNA and Dexamethasone for Synergistic Therapy in Ocular Neovascular Diseases

Introduction

Oxidant stress, abnormal angiogenesis, and inflammation are three key factors contributing to the development of ocular neovascular diseases (ONDs). This study aims to develop a multifunctional nanodrug, DEX@MPDA-Arg@Si (DMAS), which integrates mesoporous polydopamine, vascular endothelial growth factor (VEGF)-siRNA, and dexamethasone (DEX) to address these therapeutic targets.

Methods

Physicochemical properties of DMAS were measured using transmission electron microscopy and a nanoparticle size analyzer. The encapsulation efficiency and drug loading capacity of DMAS were measured using a UV-visible spectrophotometer. The in vivo therapeutic efficacy and ocular safety of DMAS were evaluated using three established mouse models, including the alkali burn-induced corneal neovascularization (CoNV) model, the oxygen-induced retinopathy (OIR) model, and the laser-induced choroidal neovascularization (CNV) model.

Results

The DMAS nanoparticles demonstrated a uniform bowl-like shape with an average size of 264.9 ± 2.5 nm and a zeta potential of -28.2 ± 4.2 mV. They exhibited high drug-loading efficiency (36.04 ± 3.60% for DEX) and excellent biocompatibility. In vitro studies confirmed its potent antioxidant, anti-inflammatory, and anti-apoptotic properties. In vivo, DMAS treatment led to significant therapeutic effects across all models. It effectively inhibited CoNV, promoted corneal repair, and modulated inflammation in the alkali burn model. In the OIR model, DMAS reduced retinal neovascularization by decreasing VEGF expression. In the laser-induced CNV model, it significantly reduced the CNV area and lesion thickness.

Conclusion

This research developed a multifunctional nanodrug, DMAS, capable of co-delivering VEGF-siRNA and DEX, offering synergistic therapeutic benefits for treating ONDs. The DMAS nanodrug demonstrates promising anti-inflammatory, antioxidative, and anti-angiogenic effects, highlighting its potential as a versatile and effective treatment for multiple ocular conditions.

Nanoparticles targeting the intestinal Fc receptor enhance intestinal cellular trafficking of semaglutide

Semaglutide is the first oral glucagon-like peptide-1 (GLP-1) analog commercially available for the treatment of type 2 diabetes. In this work, semaglutide was incorporated into poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) nanoparticles (NPs) to improve its delivery across the intestinal barrier. The nanocarriers were surface-decorated with either a peptide or an affibody that target the human neonatal Fc receptor (hFcRn), located on the luminal cell surface of the enterocytes. Both ligands were successfully conjugated with the PLGA-PEG via maleimide-thiol chemistry and thereafter, the functionalized polymers were used to produce semaglutide-loaded NPs. Monodisperse NPs with an average size of 170 nm, neutral surface charge and 3% of semaglutide loading were obtained. Both FcRn-targeted NPs exhibited improved interaction and association with Caco-2 cells (cells that endogenously express the hFcRn), compared to non-targeted NPs. Additionally, the uptake of FcRn-targeted NPs was also observed to occur in human intestinal organoids (HIOs) expressing hFcRn through microinjection into the lumen of HIOs, resulting in potential increase of semaglutide permeability for both ligand-functionalized nanocarriers. Herein, our study demonstrates valuable data and insights that the FcRn-targeted NPs has the capacity to promote intestinal absorption of therapeutic peptides.

Receptor-interacting protein kinase 2 is associated with tumor immune infiltration, immunotherapy-related biomarkers, and affects gastric cancer cells growth in vivo

Background: The objective of this study was to analyze the research trend of four RIPK genes (RIPK1, RIPK2, RIPK3, and RIPK4), their expression variations in tumors, and the correlation between RIPK2 expression and immune-related biomarkers in gastric cancer (GC). Methods: The PubMed database was utilized to investigate the research trend surrounding four RIPKs genes in tumors. The ULCAN database was employed to analyze the differential expression of these four RIPKs genes. TCGA data were utilized to examine the association between RIPK2 expression and various factors including tumor immune infiltration and immune-related biomarkers. Lastly, the impact of targeting RIPK2 on the growth of GC cells was confirmed through tumor formation assay, immunohistochemistry, and Tunnel assays. Results: In the field of tumor biology, there has been a sustained increase in research focused on the four RIPKs genes over the past decade. Four RIPKs genes are differentially expressed in a majority of tumors. Furthermore, this investigation has unveiled a connection between the expression of RIPK2 and the infiltration of four immune cells, as well as the presence of RNA methylation modifying enzymes, specifically m1A, m6A, and m5C, in GC. Additionally, RIPK2 expression was associated with the genes related to immune checkpoint regulation, as well as genes associated with immunoinhibitors and immunostimulators. It was also revealed that RIPK2 expression was correlated to immunotherapy response biomarkers, namely MSI and TMB, and tumor stemness. Ultimately, it was demonstrated that targeting the RIPK2 effectively regulated GC cells growth through the suppression of PCNA expression and the induction of apoptosis. Conclusion: The expression of RIPK2 is correlated with immune cell infiltration, RNA methyltransferase activity, tumor stemness, checkpoint-related genes, and immunotherapy-related biomarkers. Suppression of RIPK2 impedes the growth of GC cells in vivo. Consequently, RIPK2 holds promise as a viable immunotherapy target for various types of cancer.

Research progress of siVEGF complex and their application in antiangiogenic therapy

Vascular endothelial growth factor (VEGF) is an important factor in the development of some diseases such as tumors, ocular neovascular disease and endometriosis. Inhibition of abnormal VEGF expression is one of the most effective means of treating these diseases. The resistance and side effects of currently used VEGF drugs limit their application. Herein, small interfering RNA for VEGF (siVEGF) are developed to inhibit VEGF expression at the genetic level by means of RNA interference. However, as a foreign substance entering the organism, siVEGF is prone to induce an immune response or mismatch, which adversely affects the organism. It is also subjected to enzymatic degradation and cell membrane blockage, which greatly reduces its therapeutic effect. Targeted siVEGF complexes are constructed by nanocarriers to avoid their clearance by the body and precisely target cells, exerting anti-vascular effects for the treatment of relevant diseases. In addition, some multifunctional complexes allow for the combination of siVEGF with other therapeutic tools to improve the treat efficiency of the disease. Therefore, this review describes the construction of the siVEGF complex, its mechanism of action, application in anti-blood therapy, and provides an outlook on its current problems and prospects.

Plasmid containing VEGF-165 and ANG-1 dual genes packaged with fibroin-modified PEI to promote the regeneration of vascular network and dermal tissue

Reducing the cytotoxicity of cationic polymers is the major issue to their use as a gene delivery carrier. In this study, plasmids containing encoding vascular endothelial cell growth factor 165 and angiopoietin-1 were packaged with the conjugates of cationic fibroin (CSF) and polyethylenimine (PEI), instead of packaging pDNA with PEI alone, to prepare nanocomplexes (CSF+PEI)/pDNA. The complexes were loaded into a silk fibroin scaffold to enhance its function to induce microvascular network generation and dermal tissue regeneration. The results of transfecting EA.hy926 cells with the complexes in vitro showed that (CSF+PEI)/pDNA had a stronger transfection ability than PEI/pDNA. Importantly, compared with PEI as the gene carrier alone, the cell viability was significantly increased and the cytotoxicity was effectively reduced after the conjugate of CSF and PEI was used as the gene carrier. The results of angiogenesis in chick embryo chorioallantoic membranes showed that compared with scaffolds loaded with PEI/pDNA, the neovascularization ratio in scaffolds loaded with (CSF+PEI)/pDNA was significantly increased. In vivo experimental results of scaffolds implantation for full-thickness skin defects in SD rats showed that, compared with loading PEI/pDNA complex, loading (CSF+PEI)/pDNA complex in the scaffold more effectively promoted the formation of vascular network in the scaffold and accelerated the regeneration of dermal tissue. The gene delivery system established in this study has application potential not only in the regeneration of vascular-containing tissues, but also in tumor gene therapy.

Fluorinated vectors for gene delivery

INTRODUCTION

Gene delivery vectors are a crucial determinant for gene therapeutic efficacy. Usually, it is necessary to use an excess of cationic vectors to achieve better transfection efficiency. However, it will cause severe cytotoxicity. In addition, cationic vectors are not resistant to serum, suffering from reduced transfection efficiency by forming large aggregates. Therefore, there is an urgent need to develop optimized gene delivery vectors. Recently, fluorination of vectors has been extensively applied to increase the gene delivery performance because of the unique properties of both hydrophobicity and lipophobicity, and chemical and biological inertness.

AREAS COVERED

This review will discuss the fluorophilic effects that impact gene delivery efficiency, and chemical modification approaches for fluorination. Next, recent advances and applications of fluorinated polymeric and lipidic vectors in gene therapy and gene editing are summarized.

EXPERT OPINION

Fluorinated vectors are a promising candidate for gene delivery. However, it still needs further studies to obtain pure and well-defined fluorinated polymers, guarantee the biosafety, and clarify the detailed mechanism. Apart from the improvements in gene delivery, exploiting other versatility of fluorinated vectors, such as oxygen-carrying ability, high affinity with fluorine-containing drugs, and imaging property upon introducing 19^F, will further facilitate their applications in gene therapy.