A mPEG-PLGA-b-PLL copolymer carrier for adriamycin and siRNA delivery

Exploring delivery systems for targeted nanotechnology-based gene therapy in the inner ear

Hearing loss places a significant burden on our aging population. However, there has only been limited progress in developing therapeutic techniques to effectively mediate this condition. This review will outline several of the most commonly utilized practices for the treatment of sensorineural hearing loss before exploring more novel techniques currently being investigated via both in vitro and in vivo research. This review will place particular emphasis on novel gene-delivery technologies. Primarily, it will focus on techniques used to deliver genes that have been shown to encourage the proliferation and differentiation of sensory cells within the inner ear and how these technologies may be translated into providing clinically useful results for patients.

Thermosensitive gel-nano system against esophageal cancer via restoring p53 activity and boosting T-cell immunity

In esophageal cancer (EC), clinical specimen testing has uncovered a significant increase in BTB and CNC homolog 1 (BACH1) expression and a shift towards an immunosuppressive environment, alongside a notable decrease in p53 protein expression. Therefore, therapeutic strategies focusing on BACH1 inhibition and p53 upregulation appear promising. Traditional oral treatments for EC lack precision and efficacy. Here, we propose a novel approach employing tumor-targeted nanoparticles (NPs) for drug delivery. However, the formation of a drug reservoir at the esophageal site, crucial for the sustained release of therapeutics, presents significant challenges in nano-delivery systems for EC treatment. To address this, we developed a thermosensitive hydrogel composed of F127 and tannic acid, serving as a vehicle for NP loading. These NPs, synthesized through the emulsion/volatization methods of mPEG-PLGA-PLL-cRGD, facilitate in situ drug delivery. Upon contacting esophageal tissue, the hydrogel transitions to a gel, adhering to the lining and enabling sustained release of encapsulated therapeutics. The formulation encompasses NPs laden with small interfering RNA targeting BACH1 (siBACH1) and the p53 activator PRIMA-1, creating a cohesive gel-nano system. Preliminary biological assessments demonstrate that this injectable, thermosensitive gel-nano system adheres effectively to esophageal tissue and targets EC cells. For better modeling clinical outcomes, a patient-derived organoid xenograft (PDOX) model was innovated, involving transplantation of EC-derived organoids into humanized mice, reconstructed with peripheral blood mononuclear cells (PBMCs). Post-treatment analysis showed substantial EC growth inhibition (89.51% tumor inhibition rate), significant BACH1 level reduction, restored anti-tumor immune responses, and pronounced tumor apoptosis. In summary, our study introduces a thermosensitive gel-nano system for EC treatment via restoring p53 activity and boosting T-cell immunity, with potential for clinical application.

Recent Advances of Multifunctional PLGA Nanocarriers in the Management of Triple-Negative Breast Cancer

Even though chemotherapy stands as a standard option in the therapy of TNBC, problems associated with it such as anemia, bone marrow suppression, immune suppression, toxic effects on healthy cells, and multi-drug resistance (MDR) can compromise their effects. Nanoparticles gained paramount importance in overcoming the limitations of conventional chemotherapy. Among the various options, nanotechnology has appeared as a promising path in preclinical and clinical studies for early diagnosis of primary tumors and metastases and destroying tumor cells. PLGA has been extensively studied amongst various materials used for the preparation of nanocarriers for anticancer drug delivery and adjuvant therapy because of their capability of higher encapsulation, easy surface functionalization, increased stability, protection of drugs from degradation versatility, biocompatibility, and biodegradability. Furthermore, this review also provides an overview of PLGA-based nanoparticles including hybrid nanoparticles such as the inorganic PLGA nanoparticles, lipid-coated PLGA nanoparticles, cell membrane-coated PLGA nanoparticles, hydrogels, exosomes, and nanofibers. The effects of all these systems in various in vitro and in vivo models of TNBC were explained thus pointing PLGA-based NPs as a strategy for the management of TNBC.

TH-302-loaded nanodrug reshapes the hypoxic tumour microenvironment and enhances PD-1 blockade efficacy in gastric cancer

BACKGROUND

Hypoxia, a common characteristic of the tumour microenvironment, is involved in tumour progression and immune evasion. Targeting the hypoxic microenvironment has been implicated as a promising antitumour therapeutic strategy. TH-302 can be selectively activated under hypoxic conditions. However, the effectiveness of TH-302 in gastric cancer combined immunotherapy remains unclear.

METHODS

We designed mPEG-PLGA-encapsulated TH-302 (TH-302 NPs) to target the hypoxic area of tumour tissues. A particle size analyzer was used to measure the average size and zeta potential of TH-302 NPs. The morphology was observed by transmission electron microscopy and scanning electron microscopy. The hypoxic area of tumour tissues was examined by immunofluorescence assays using pimonidazole. Flow cytometry analysis was performed to measure the levels of TNF-α, IFN-γ, and granzyme B. The synergistic antitumour activity of the combination of TH-302 NPs with anti-PD-1 (α-PD-1) therapy was assessed in vitro and in vivo. Haematoxylin and eosin staining of major organs and biochemical indicator detection were performed to investigate the biological safety of TH-302 NPs in vivo.

RESULTS

TH-302 NPs inhibited the proliferation and promoted the apoptosis of gastric cancer cells under hypoxic conditions. In vitro and in vivo experiments confirmed that TH-302 NPs could effectively alleviate tumour hypoxia. TH-302 NPs exhibited high bioavailability, effective tumour-targeting ability and satisfactory biosafety. Moreover, the combination of TH-302 NPs with α-PD-1 significantly improved immunotherapeutic efficacy in vivo. Mechanistically, TH-302 NPs reduced the expression of HIF-1α and PD-L1, facilitated the infiltration of CD8+ T cells and increased the levels of TNF-α, IFN-γ, and granzyme B in tumours, thereby enhancing the efficacy of α-PD-1 therapy.

CONCLUSION

TH-302 NPs alleviated the hypoxic tumour microenvironment and enhanced the efficacy of PD-1 blockade. Our results provide evidence that TH-302 NPs can be used as a safe and effective nanodrug for combined immunotherapy in gastric cancer treatment.

Polymeric-Micelle-Based Delivery Systems for Nucleic Acids

Nucleic acids can modulate gene expression specifically. They are increasingly being utilized and show huge potential for the prevention or treatment of various diseases. However, the clinical translation of nucleic acids faces many challenges due to their rapid clearance after administration, low stability in physiological fluids and limited cellular uptake, which is associated with an inability to reach the intracellular target site and poor efficacy. For many years, tremendous efforts have been made to design appropriate delivery systems that enable the safe and effective delivery of nucleic acids at the target site to achieve high therapeutic outcomes. Among the different delivery platforms investigated, polymeric micelles have emerged as suitable delivery vehicles due to the versatility of their structures and the possibility to tailor their composition for overcoming extracellular and intracellular barriers, thus enhancing therapeutic efficacy. Many strategies, such as the addition of stimuli-sensitive groups or specific ligands, can be used to facilitate the delivery of various nucleic acids and improve targeting and accumulation at the site of action while protecting nucleic acids from degradation and promoting their cellular uptake. Furthermore, polymeric micelles can be used to deliver both chemotherapeutic drugs and nucleic acid therapeutics simultaneously to achieve synergistic combination treatment. This review focuses on the design approaches and current developments in polymeric micelles for the delivery of nucleic acids. The different preparation methods and characteristic features of polymeric micelles are covered. The current state of the art of polymeric micelles as carriers for nucleic acids is discussed while highlighting the delivery challenges of nucleic acids and how to overcome them and how to improve the safety and efficacy of nucleic acids after local or systemic administration.

Gut microbial metabolite butyrate improves anticancer therapy by regulating intracellular calcium homeostasis

BACKGROUND AND AIMS

Gut microbiota are recognized to be important for anticancer therapy, yet the underlying mechanism is not clear. Here, through the analysis of clinical samples, we identify the mechanism by which the gut microbial metabolite butyrate inhibits HCC and then explore new strategies for HCC treatment.

APPROACH AND RESULTS

In our study, we demonstrate that gut microbial metabolite butyrate improves anticancer therapy efficacy by regulating intracellular calcium homeostasis. Using liquid chromatography-mass spectrometry analysis, we found that butyrate metabolism is activated in HCC patients compared with healthy individuals. Butyrate levels are lower in the plasma of HCC patients by gas chromatography-mass spectrometry (GC-MS) analysis. Butyrate supplementation or depletion of short-chain Acyl-CoA dehydrogenase (SCAD) gene (ACADS), encoding a key enzyme for butyrate metabolism, significantly inhibits HCC proliferation and metastasis. The profiling analysis of genes upregulated by butyrate supplementation or ACADS knockdown reveals that calcium signaling pathway is activated, leading to dysregulation of intracellular calcium homeostasis and production of reactive oxygen species. Butyrate supplementation improves the therapy efficacy of a tyrosine kinase inhibitor sorafenib. On the basis of these findings, we developed butyrate and sorafenib coencapsulated mPEG-PLGA-PLL nanoparticles coated with anti-GPC3 antibody (BS@PEAL-GPC3) to prolong the retention time of drugs and enhance drug targeting, leading to high anticancer efficacy. BS@PEAL-GPC3 nanoparticles significantly reduce HCC progression. In addition, BS@PEAL-GPC3 nanoparticles display excellent HCC targeting with excellent safety.

CONCLUSIONS

In conclusion, our findings provide new insight into the mechanism by which the gut microbial metabolites inhibit HCC progression, suggesting a translatable therapeutics approach to enhance the clinical targeted therapeutic efficacy.

Core-Shell Structured PLGA Particles Having Highly Controllable Ketoprofen Drug Release

The non-steroid anti-inflammatory drug ketoprofen (KP) as a model molecule is encapsulated in different poly(lactide-co-glycolide) (PLGA) nanostructured particles, using Tween20 (TWEEN) and Pluronic F127 (PLUR) as stabilizers to demonstrate the design of a biocompatible colloidal carrier particles with highly controllable drug release feature. Based on TEM images the formation of well-defined core-shell structure is highly favorable using nanoprecipitation method. Stabile polymer-based colloids with ~200-210 nm hydrodynamic diameter can be formed by successful optimization of the KP concentration with the right choice of stabilizer. Encapsulation efficiency (EE%) of 14-18% can be achieved. We clearly confirmed that the molecular weight of the stabilizer thus its structure greatly controls the drug release from the PLGA carrier particles. It can be determined that ~20% and ~70% retention is available with the use of PLUR and TWEEN, respectively. This measurable difference can be explained by the fact that the non-ionic PLUR polymer provides a steric stabilization of the carrier particles in the form of a loose shell, while the adsorption of the non-ionic biocompatible TWEEN surfactant results in a more compact and well-ordered shell around the PLGA particles. In addition, the release property can be further tuned by decreasing the hydrophilicity of PLGA by changing the monomer ratio in the range of ~20-60% (PLUR) and 70-90% (TWEEN).

Tetracycline-grafted mPEG-PLGA micelles for bone-targeting and osteoporotic improvement

Aim: We aimed to create a nano drug delivery system with tetracycline (TC)-grafted methoxy poly-(ethylene-glycol)‒poly-(D, L-lactic-co-glycolic acid) (mPEG‒PLGA) micelles (TC‒mPEG‒PLGA) with TC and mPEG‒PLGA for potential bone targeting. Prospectively, TC‒mPEG‒PLGA aims to deliver bioactive compounds, such as astragaloside IV (AS), for osteoporotic therapy.

Methods: Preparation and evaluation of TC‒mPEG‒PLGA were accomplished via nano-properties, cytotoxicity, uptake by MC3T3-E1 cells, ability of hydroxyapatite targeting and potential bone targeting in vivo, as well as pharmacodynamics in a rat model.

Results: The measured particle size of AS-loaded TC‒mPEG‒PLGA micelles was an average of 52.16 ± 2.44 nm, which exhibited a sustained release effect compared to that by free AS. The TC‒mPEG‒PLGA demonstrated low cytotoxicity and was easily taken by MC3T3-E1 cells. Through assaying of bone targeting in vitro and in vivo, we observed that TC‒mPEG‒PLGA could effectively increase AS accumulation in bone. A pharmacodynamics study in mice suggested potentially increased bone mineral density by AS-loaded TC‒mPEG‒PLGA in ovariectomized rats compared to that by free AS.

Conclusion: The nano drug delivery system (TC‒mPEG‒PLGA) could target bone in vitro and in vivo, wherein it may be used as a novel delivery method for the enhancement of therapeutic effects of drugs with osteoporotic activity.

Effects of Surgery Combined with Different Chemotherapy on Matrix Metalloproteinase-9 and Tissue Inhibitors of Metalloproteinase-1 in Children with Neuroblastoma

Background

Neuroblastoma (NB) is a common extracranial malignancy in children and accounts for 15% of all cancer-related deaths in children, with the 5-year survival of patients in an advanced stage being lower than 40%. Preoperative adjuvant chemotherapy has been reported to facilitate surgical resection and improve the 2-year survival of patients.

Objective

To analyze the efficacy of surgery plus different chemotherapy on children with NB and to investigate the correlation of matrix metalloproteinase-9 (MMP-9) and tissue inhibitors of metalloproteinase-1 (TIMP-1) with chemotherapy efficacy.

Methods

From April 2005 to May 2017, a total of 92 cases of NB treated in our hospital were assessed for eligibility and recruited. They were assigned at a ratio of 1: 1 to receive either CAV (cyclophosphamide + vincristine + adriamycin) (group A) and EP (etoposide + cisplatin) alternately or TOPO (topotecan) + CTX (cytoxan) + CiE (etoposide + cisplatin) + CPV (cyclophosphamide + pirarubicin + vincristine) (group B). The outcome measures include chemotherapy efficacy, surgical resection rates, complications, 2-year recurrence, and 2-year survival. The levels of NK cells, CD4+/CD8+ cells, MMP-9, TIMP-1, and urine catecholamine (VMA) in peripheral blood of patients before and after initial chemotherapy were determined to analyze the correlation of MMP-9, TIMP-1, and VMA with the efficacy of chemotherapy.

Results

The two groups had similar efficacy (84.00% vs. 95.24%) and surgical resection rates (60.00% vs. 61.90%) after the initial chemotherapy (P > 0.05). Surgery for all eligible patients was successful after second chemotherapy. All eligible patients showed myelosuppression after chemotherapy, including 48 cases with stages I-II (52.17%) and 44 cases with stages III-IV (47.83%). The ratio of CD4+/CD8+ cells, MMP-9, TIMP-1, and VMA expression levels in peripheral blood of patients decreased (P < 0.05) after chemotherapy, and the ratio of CD4+/CD8+ cells was further reduced after surgery (P < 0.05), while natural killer (NK) cells levels increased (P < 0.05). However, intergroup differences were absent in the incidence of myelosuppression, CD4+/CD8+ cell ratio, NK cells, MMP-9, TIMP-1, and VMA expression levels (P > 0.05). MMP-9 and TIMP-1 were positively correlated with VMA (P < 0.05), and the expression levels of MMP-9 and TIMP-1 and VMA after chemotherapy were negatively correlated with chemotherapy efficiency (P < 0.05). Patients with high expressions of MMP-9, TIMP-1, and VMA were associated with lower 2-year survival versus those with low expressions (P < 0.05).

Conclusion

Surgery plus chemotherapy for children with NB yields a promising clinical efficacy and a favorable surgical resection outcome. MMP-9 and TIMP-1 may be the potential biological indicators for chemotherapy efficiency and have a reference value for following surgical treatment of patients.

Microfluidic-Assisted Preparation of Targeted pH-Responsive Polymeric Micelles Improves Gemcitabine Effectiveness in PDAC: In Vitro Insights

Simple Summary

This research suggests a new potential therapeutic approach to pancreatic ductal adenocarcinoma to improve drug effectiveness and overcome drug resistance. A double actively targeted gemcitabine delivery system, consisting of polymeric micelles, was developed by microfluidic technique to ensure a narrow size distribution, a good colloidal stability, and drug-encapsulation efficiency for the selective and controlled release of the loaded drug, in response to the pH variations and uPAR expression in tumors. In vitro studies assessed that the release of the drug in the acidic environment was higher than in the neutral one, and that the pH-responsive and uPAR-targeted polymeric micelles enhanced the antitumor properties of gemcitabine in models resembling the pancreatic tumor microenvironment.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) represents a great challenge to the successful delivery of the anticancer drugs. The intrinsic characteristics of the PDAC microenvironment and drugs resistance make it suitable for therapeutic approaches with stimulus-responsive drug delivery systems (DDSs), such as pH, within the tumor microenvironment (TME). Moreover, the high expression of uPAR in PDAC can be exploited for a drug receptor-mediated active targeting strategy. Here, a pH-responsive and uPAR-targeted Gemcitabine (Gem) DDS, consisting of polymeric micelles (Gem@TpHResMic), was formulated by microfluidic technique to obtain a preparation characterized by a narrow size distribution, good colloidal stability, and high drug-encapsulation efficiency (EE%). The Gem@TpHResMic was able to perform a controlled Gem release in an acidic environment and to selectively target uPAR-expressing tumor cells. The Gem@TpHResMic displayed relevant cellular internalization and greater antitumor properties than free Gem in 2D and 3D models of pancreatic cancer, by generating massive damage to DNA, in terms of H2AX phosphorylation and apoptosis induction. Further investigation into the physiological model of PDAC, obtained by a co-culture of tumor spheroids and cancer-associated fibroblast (CAF), highlighted that the micellar system enhanced the antitumor potential of Gem, and was demonstrated to overcome the TME-dependent drug resistance. In vivo investigation is warranted to consider this new DDS as a new approach to overcome drug resistance in PDAC.

Comparison of triblock copolymeric micelles based on α- and ε-poly(L-lysine): a Cornelian choice

Due to the lack of safe carriers for the delivery of small interfering RNA (siRNA), clinical applications of nucleotide-based therapeutics have been limited. In this study, biodegradable amphiphilic triblock copolymers with tailored molecular weights for each block composed of methoxy poly(ethylene glycol) (2000 g/mol), poly(L-lysine) (1300 g/mol) and poly(D,L-lactic acid) (1800 g/mol) (mPEG45-α-PLL10-PLA25) were synthesized and fully characterized. The peptide synthesis was carried out on a solid phase to limit the presence of cationic charges. The arrangement and availability of cationic amino groups within a micellar vector were investigated to determine the colloidal stability as well as the predisposition of these systems to vectorize siRNAs in addition to their already known ability to improve the solubility of hydrophobic compounds. For this purpose, a triblock copolymer containing an epsilon poly(L-lysine) was synthesized similarly. Accordingly, the arrangement of the cationic segment modifies the rigidity involving a complexation constraint due to limited cationic charges available on the surface, which can compromise the efficiency of delivery into cells. In addition, the two vectors were biocompatible in different human cell lines.

ROS-responsive EPO nanoparticles ameliorate ionizing radiation-induced hematopoietic injury

Stimulus-responsive polymer materials have attracted much attention as drug carriers because of the ability to deliver drugs to the active site. Reactive oxygen species (ROS) play crucial roles in cellular signaling and regulation of oxygen homeostasis. However, ROS are present in abnormally high levels in many pathological environments. Based on the above points, three-arm poly(lactic-co-glycolic acid)-PO-poly(ethylene glycol) (3s-PLGA-PO-PEG or simply PP) was synthesized by using peroxalate esters (PO) as hydrogen peroxide-responsive linkages. PP was used to deliver promote hematopoietic recovery drugs erythropoietin (EPO) and EPO nanoparticles (EPO NPs) were prepared. We established a hematopoietic system injury model by ionizing radiation (IR) and unexpectedly found the good therapeutic effect of blank PP. Moreover, the administration of EPO NPs obviously decreased IR-induced ROS in bone marrow cells (BMCs) and reconstituted hematopoietic stem cells in BMCs. This study reveals a novel ROS-responsive polymer material that could be employed to remove excess ROS in the lesion and promote the efficacy of drug therapy.

Asynchronous blockade of PD-L1 and CD155 by polymeric nanoparticles inhibits triple-negative breast cancer progression and metastasis

PD-L1/PD-1 blockade therapy shows durable responses to triple-negative breast cancer (TNBC), but the response rate is low. CD155 promotes tumor metastasis intrinsically and modulates the immune response extrinsically as the ligand of DNAM-1 (costimulatory receptor) and TIGIT/CD96 (coinhibitory receptors). Herein, we verified that TNBC cells coexpressed PD-L1 and CD155. By examining the receptors of PD-L1 and CD155 on TNBC tumor-infiltrating lymphocytes (TILs) over time, we observed that PD-1 and DNAM-1 were upregulated early, whereas CD96 and TIGIT were upregulated late in CD8⁺ TILs. Based on these findings, we developed CD155 siRNA (siCD155)-loaded mPEG-PLGA-PLL (PEAL) nanoparticles (NPs) coated with PD-L1 blocking antibodies (P/PEAL_siCD155) to asynchronously block PD-L1 and CD155 in a spatiotemporal manner. P/PEAL_siCD155 maximized early-stage CD8⁺ T cell immune surveillance against 4T1 tumor, whereas reversed inhibition status of the late stage CD8⁺ T cells to prevent 4T1 tumor immune escape. In addition, the combination of P/PEAL_siCD155 and tumor-specific CD8 T cells induced immunogenic cell death (ICD) of 4T1 cells to further boost immune checkpoint therapy. Most importantly, P/PEAL_siCD155 displayed excellent TNBC targeting and induced CD8⁺ TILs-dominant intratumor antitumor immunity to efficiently inhibit TNBC progression and metastasis with excellent safety in a syngeneic 4T1 orthotopic TNBC tumor model.

Tracking mesenchymal stem cells with Ir(III) complex-encapsulated nanospheres in cranium defect with postmenopausal osteoporosis

Osteoporosis (OP) is a significant public health problem with associated fragility fractures, thereby causing large bone defects and difficulty in self-repair. The introduction of human mesenchymal stem cells (hMSCs) is the most promising platform in bone tissue engineering for OP therapy, which induces less side effects than conventional medication. However, the safety and efficiency of the cell-based OP therapy requires the ability to monitor the cell's outcome and biodistribution after cell transplantation. Therefore, we designed an in vivo system to track hMSCs in real time and simultaneously attempted to obtain a significant therapeutic effect during the bone repair process. In this study, we synthesized Ir(III) complex, followed by encapsulation with biodegradable methoxy-poly(ethylene glycol) poly(lactic-co-glycolic acid) nanospheres through double emulsions strategy. The Ir(III) complex nanospheres did not affect hMSC proliferation, stemness, and differentiation and realized highly efficient and long-term cellular labeling for at least 25 days in vivo. The optimal transplantation conditions were also determined first by injecting a gradient number of labeled hMSCs percutaneously into the cranial defect of the nude mouse model. Next, we applied this method to ovariectomy-induced OP mice. Results showed long-term optical imaging with high fluorescence intensity and computed tomography (CT) scanning with significantly increased bone formation between the osteoporotic and sham-operated bones. During the tracking process, two mice from each group were sacrificed at two representative time points to examine the bony defect bridging via micro-CT morphometric analyses. Our data showed remarkable promise for efficient hMSC tracking and encouraging treatment in bioimaging-guided OP stem cell therapy.

Polymeric nanoparticles for RNA delivery

As exemplified by recent clinical approval of RNA drugs including the latest COVID-19 mRNA vaccines, RNA therapy has demonstrated great promise as an emerging medicine. Central to the success of RNA therapy is the delivery of RNA molecules into the right cells at the right location. While the clinical success of nanotechnology in RNA therapy has been limited to lipid-based nanoparticles currently, polymers, due to their tunability and robustness, have also evolved as a class of promising material for the delivery of various therapeutics including RNAs. This article overviews different types of polymers used in RNA delivery and the methods for the formulation of polymeric nanoparticles and highlights recent progress of polymeric nanoparticle-based RNA therapy.

Enhanced Anti-Cancer Effect of Folate-Conjugated Olaparib Nanoparticles Combined with Radiotherapy in Cervical Carcinoma

BACKGROUND

Radiotherapy (RT), one of the main treatments for cervical cancer, has tremendous potential for improvement in the efficacy. Poly (ADP-ribose) polymerase (PARP) is a key enzyme in the repair of DNA strand breaks (DSB). Olaparib (Ola) is a PARP inhibitor that is involved in preventing the release of PARP from RT-induced damaged DNA to potentiate the effect of RT. Although the basic mechanism of Ola's radiosensitization is well known, the radiosensitization mechanism of its nanomedicine is still unclear. In addition, the lack of tumor tissue targeting is a major obstacle for the clinical success of Ola.

MATERIALS AND METHODS

In this study, we developed folate-conjugated active targeting olaparib nanoparticles (ATO) and investigated the anti-tumor effect of ATO combined with radiotherapy (RT) in nude mice using cervical cancer xenograft models. We used folate (FA)-conjugated poly (ε-caprolactone)-poly (ethyleneglycol)-poly (e-caprolactone) (PCEC) copolymer to prepare ATO via emulsification/solvent diffusion. Further, we evaluated ATO particle size, potential, encapsulation efficiency, and in vitro release characteristics, and evaluated the shape of ATO via transmission electron microscopy (TEM). We then performed MTT and cell uptake assays to detect cytotoxicity and targeting uptake in vitro. We investigated the anti-tumor properties of ATO in vivo by apoptosis test, 18 F-FDG PET/CT, and immunohistochemical analysis. Finally, the xenografted tumor in nude mice was subjected to RT and/or ATO treatment.

RESULTS

The results confirmed that ATO in combination with RT significantly inhibited tumor growth and prolonged survival time of tumor-bearing mice. This may be related to the inhibition of tumor proliferation and DNA damage repair and induction of cell apoptosis in vivo.

CONCLUSION

The ATO developed in this study may represent a novel formulation for olaparib delivery and have promising potential for treating tumors with an over-expression of folate receptors.

Syringic acid delivered via mPEG-PLGA-PLL nanoparticles enhances peripheral nerve regeneration effect

Aim: To deliver syringic acid (SA) with a nanocarrier and enhance its function. Materials & methods: mPEG-PLGA-PLL (PEAL) nanoparticles were used to deliver SA. The characterization, storage stability, drug release, blood-compatibility and biocompatibility of SA-PEAL were detected by in vitro and in vivo assays. Cellular phenotypic experiments and rat sciatic nerve injury models were used to evaluate the function of SA-PEALs. Results: SA-PEAL had good storage stability, blood-compatibility and biocompatibility and could slowly release SA. SA-PEAL significantly enhanced the proliferation and migration ability of Schwann cells and function recovery of injured sciatic nerves. Conclusion: Our study provides an effective nano-delivery system for enhancing the neural repair function of SA and promoting further applications of SA.

Progress on ocular siRNA gene-silencing therapy and drug delivery systems

Age-related macular degeneration (AMD) and glaucoma are global ocular diseases with high blindness rate. RNA interference (RNAi) is being increasingly used in the treatment of these disorders with siRNA drugs, bevasiranib, AGN211745 and PF-04523655 for AMD, and SYL040012 and QPI-1007 for glaucoma. Administration routes and vectors of gene drugs affect their therapeutic effect. Compared with the non-viral vectors, viral vectors have limited payload capacity and potential immunogenicity. This review summarizes the progress of the ocular siRNA gene-silencing therapy by focusing on siRNA drugs for AMD and glaucoma already used in clinical research, the main routes of drug delivery and the non-viral vectors for siRNA drugs.

Lipid-based Nanocarriers for siRNA Delivery: Challenges, Strategies and the Lessons Learned from the DODAX: MO Liposomal System

The possibility of using the RNA interference (RNAi) mechanisms in gene therapy was one of the scientific breakthroughs of the last century. Despite the extraordinary therapeutic potential of this approach, the need for an efficient gene carrier is hampering the translation of the RNAi technology to the clinical setting. Although a diversity of nanocarriers has been described, liposomes continue to be one of the most attractive siRNA vehicles due to their relatively low toxicity, facilitated siRNA complexation, high transfection efficiency and enhanced pharmacokinetic properties. This review focuses on RNAi as a therapeutic approach, the challenges to its application, namely the nucleic acids' delivery process, and current strategies to improve therapeutic efficacy. Additionally, lipid-based nanocarriers are described, and lessons learned from the relation between biophysical properties and biological performance of the dioctadecyldimethylammonium:monoolein (DODAX: MO) system are explored. Liposomes show great potential as siRNA delivery systems, being safe nanocarriers to protect nucleic acids in circulation, extend their half-life time, target specific cells and reduce off-target effects. Nevertheless, several issues related to delivery must be overcome before RNAi therapies reach their full potential, namely target-cell specificity and endosomal escape. Understanding the relationship between biophysical properties and biological performance is an essential step in the gene therapy field.

Hybrid polymers bearing oligo-l-lysine(carboxybenzyl)s: synthesis and investigations of secondary structure

Hybrid polymers of peptides resembling (partially) folded protein structures are promising materials in biomedicine, especially in view of folding-interactions between different segments. In this study polymers bearing repetitive peptidic folding elements, composed of N-terminus functionalized bis-ω-ene-functional oligo-l-lysine(carboxybenzyl(Z))s (Lys_n) with repeating units (n) of 3, 6, 12, 24 and 30 were successfully synthesized to study their secondary structure introduced by conformational interactions between their chains. The pre-polymers of ADMET, narrowly dispersed Lys_ns, were obtained by ring opening polymerization (ROP) of N-carboxyanhydride (NCA) initiated with 11-amino-undecene, following N-terminus functionalization with 10-undecenoyl chloride. The resulting Lys_ns were subsequently polymerized via ADMET polymerization by using Grubbs’ first generation (G1) catalyst in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) generating the ADMET polymers (A-[Lys_n]_m) (m = 2–12) with molecular weights ranging from 3 to 28 kDa, displaying polydispersity (Đ) values in the range of 1.5–3.2. After chemical analyses of Lys_ns and A-[Lys_n]_ms by ¹H-NMR, GPC and MALDI-ToF MS, secondary structural investigations were probed by CD spectroscopy and IR spectroscopy in 2,2,2-trifluoroethanol (TFE). In order to study A-[Lys_n]_ms with defined molecular weights and low polydispersity values (Đ = 1.03–1.48), the ADMET polymers A-[Lys_n=3]_m=3 and A-[Lys_n=24]_m=4 were fractionated by preparative GPC, and subsequently analysed by ¹H-NMR, analytical GPC, MALDI-ToF MS and CD spectroscopy. We can demonstrate the influence of chain length of the generated polymers on the formation of secondary structures by comparing Lys_ns with varying n values to the ADMET-polymers with the help of spectroscopic techniques such as CD and FTIR-spectroscopy in a helicogenic solvent.

We demonstrate the influence of chain length of segmented polymers bearing dynamic folding elements onto the formation of secondary structures with the help of spectroscopic techniques such as CD and FTIR-spectroscopy in a helicogenic solvent.

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.

Local delivery of arsenic trioxide nanoparticles for hepatocellular carcinoma treatment

Hepatocellular carcinoma (HCC) is a malignancy with a poor prognosis. Surgery combined with chemotherapy has been recommended as a curative regimen for HCC. Nevertheless, the anticancer mechanisms of chemicals in hepatocellular carcinoma remain unclear. Pyroptosis is a type of programmed necrosis, and its mechanism in hepatocellular carcinoma is poorly understood. The efficacy and mechanism of arsenic trioxide nanoparticles in the treatment of HCC were explored in this research. Arsenic trioxide alone and arsenic trioxide nanoparticles were conveniently administered to mice intratumorally using a needle. Compared with As2O3, As2O3 nanoparticles (As2O3-NPs) showed better inhibition, promoted greater LDH release, and induced cell morphology indicative of pyroptosis in vitro. Compared with the free drug, As2O3-NPs increased GSDME-N expression and decreased Dnmt3a, Dnmt3b, and Dnmt1 expression in Huh7 cells. In vivo, As2O3-NPs induced a significant decrease in the expression of Dnmt3a, Dnmt3b and Dnmt1, but significantly upregulated the expression of GSDME-N (gasdermin E (GSDME) was originally found to be related to deafness; recently, it has been defined as a gasdermin family member associated with pyroptosis). As2O3-NPs inhibited tumor growth more strongly than As2O3 or control, a finding likely attributed to the downregulation of PCNA and DNMT-related proteins and the upregulation of GSDME-N.

Cyclic β-(1, 2)-glucan blended poly DL lactic co glycolic acid (PLGA 10:90) nanoparticles for drug delivery

Our group had previously reported the encapsulation efficiency of cyclic β-(1, 2)-glucan for various drugs. The current study is aimed at evaluating the use of glucan as a drug carrier system by blending with poly lactic-co- glycolic acid (L:G = 10:90). Nanoparticles of glucan (0.5, 5, 10 and 20 wt %) blended with PLGA and gentamicin were synthesized. Encapsulation efficiency was higher for the blends (93% with 20 wt % of glucan) than the PLGA alone (79.8%). The presence of glucan enhanced both the biodegradability, and biocompatibility of PLGA. Degradation of the nanoparticles in vitro, was autocatalytic with an initial burst release of active drug and the release profile was modeled using the Korsmeyer-Peppas scheme. In vivo studies indicated that the drug released from the blends had high volume of distribution, and greater clearance from the system. Pharmacokinetics of the drug was predicted using a double exponential decay model. Blending with PLGA improved the drug release characteristics of the cyclic β-(1, 2)-glucan.

Synergistic effect of functionalized poly(l-lactide) with surface-modified MgO and chitin whiskers on osteogenesis in vivo and in vitro

Favorable cytocompatibility and osteogenesis potential are critical for the development of a bone repair material. In this study, two types of surface-modified whiskers, grafted magnesia and chitin (g-MgO and g-CHN) whiskers, were synthesized and introduced into a poly(l-lactide) (PLLA) matrix singly or together to prepare PLLA/g-MgO/g-CHN composite films and bone nails via injection molding. On the account of the synergetic contribution of g-MgO and g-CHN whiskers, the enhanced cell adhesion, spreading, proliferation of mouse embryo osteoblast precursor (MC3T3-E1) cells, as well as the alteration of cell-cycle and inhibition of cell apoptosis, were observed on PLLA/g-MgO/g-CHN film as compared to pure PLLA, PLLA/g-MgO and PLLA/g-CHN films. More importantly, the highest level of the secretion of ALP and the formation of calcium deposition, accompanied with expression of osteogenesis genes (ALP, Runx-2, COL I, OCN) in vitro were obtained for the PLLA/g-MgO/g-CHN film among all of the material groups. Additionally, the PLLA and PLLA composite bone nails were implanted in rabbits' femurs and new bone formation was detected on PLLA/g-MgO/g-CHN group after 16 weeks of implantation by 3D reconstruction of micro-CT and histological analyses. Besides, the bending strength of defected bone repaired by PLLA/g-MgO/g-CHN bone nail was high to 48 MPa, which was far stronger than other bone nail groups. Overall, this study demonstrated the addition of g-MgO and g-CHN whiskers together in PLLA matrix played a synergistic promoting role in cell affinity and osteogenic differentiation, and the developed PLLA/g-MgO/g-CHN composites hold great potential in fields of bone repair.

Doxorubicin-loaded protease-activated near-infrared fluorescent polymeric nanoparticles for imaging and therapy of cancer

INTRODUCTION

Despite significant progress in the field of oncology, cancer remains one of the leading causes of death. Chemotherapy is one of the most common treatment options for cancer patients but is well known to result in off-target toxicity. Theranostic nanomedicines that integrate diagnostic and therapeutic functions within an all-in-one platform can increase tumor selectivity for more effective chemotherapy and aid in diagnosis and monitoring of therapeutic responses.

MATERIAL AND METHODS

In this work, theranostic nanoparticles were synthesized with commonly used biocompatible and biodegradable polymers and used as cancer contrast and therapeutic agents for optical imaging and treatment of breast cancer. These core-shell nanoparticles were prepared by nanoprecipitation of blends of the biodegradable and biocompatible amphiphilic copolymers poly(lactic-co-glycolic acid)-b-poly-l-lysine and poly(lactic acid)-b-poly(ethylene glycol). Poly-l-lysine in the first copolymer was covalently decorated with near-infrared fluorescent Alexa Fluor 750 molecules.

RESULTS

The spherical nanoparticles had an average size of 60-80 nm. The chemotherapeutic drug doxorubicin was encapsulated in the core of nanoparticles at a loading of 3% (w:w) and controllably released over a period of 30 days. A 33-fold increase in near-infrared fluorescence, mediated by protease-mediated cleavage of the Alexa Fluor 750-labeled poly-l-lysine on the surface of the nanoparticles, was observed upon interaction with the model protease trypsin. The cytocompatibility of drug-free nanoparticles and growth inhibition of drug-loaded nanoparticles on MDA-MB-231 breast cancer cells were investigated with a luminescence cell-viability assay. Drug-free nanoparticles were found to cause minimal toxicity, even at high concentrations (0.2-2,000 µg/mL), while doxorubicin-loaded nanoparticles significantly reduced cell viability at drug concentrations >10 µM. Finally, the interaction of the nanoparticles with breast cancer cells was studied utilizing fluorescence microscopy, demonstrating the potential of the nanoparticles to act as near-infrared fluorescence optical imaging agents and drug-delivery carriers.

CONCLUSION

Doxorubicin-loaded, enzymatically activatable nanoparticles of less than 100 nm were prepared successfully by nanoprecipitation of copolymer blends. These nanoparticles were found to be suitable as controlled drug delivery systems and contrast agents for imaging of cancer cells.

Simple and rational design of a polymer nano-platform for high performance of HCV related miR-122 reduction in the liver

microRNA-122 (miR-122) is a kind of non-coding RNA expressed specifically in the liver and accumulating evidence elucidates its relationship with HCV virus replication. The utilization of anti-miRNA oligonucleotide (antimiR) offers tremendous potential for future HCV infection therapy. However, multiple existing problems, such as targeting and stability, impede in vivo application of antimiR. To overcome them, we synthesized monomethoxy (polyethylene glycol)-poly (d,l lactide-co-glycolide)-poly (l-lysine) (mPEG-b-PLGA-b-PLL) materials to deliver miR-122 antagomir (AN), and formed stable and well-distributed AN-loaded mPEG-b-PLGA-b-PLL nanoparticles (NP-AN). NP-AN showed a high degree of miR-122 inhibition after 72 h in vitro. In vivo results showed an NP-AN "leak" through a hepatic sinusoid to reach hepatocytes and over 90% reduction of miR-122 after being injected with NP-AN for 72 h. Besides, the inhibition of miR-122 lasted for 28 days with limited dosage in vivo. This study strongly suggests that the silencing of miR-122 was enhanced and the reduction of miR-122 expression could be extended by utilizing an mPEG-b-PLGA-b-PLL nano-platform, which potentially facilitate further studies on miRNA function loss and related RNAi therapy for HCV infection.

Improved synergetic therapy efficiency of cryoablation and nanoparticles for MCF-7 breast cancer

AIM

Current cryoablation therapy easily induces a high tumor recurrence, it is therefore necessary to develop an effective method to enhance its antitumor efficacy.

MATERIALS & METHODS

We solve the aforementioned problem by introducing doxorubicin (DOX) loading methoxy polyethylene glycol-polylactic-co-glycolic acid-poly-L-lysine-cyclic arginine-glycine-aspartic acid peptide nanoparticles (DOX nanoparticles) in the process of cryoablation.

RESULTS

The combination of cryoablation and DOX nanoparticles greatly decreases the recurrence rate of breast cancer, which is owing to the specific targeting therapy of DOX nanoparticles for residuary breast cancer cells after cryoablation. Therefore, the survival time of MCF-7 breast cancer bearing mice significantly increases.

CONCLUSION

The synergetic therapy of cryoablation and DOX nanoparticles is an effective therapy means for breast cancer. This strategy provides new means for treating breast cancer.

Enhanced delivery of biodegradable mPEG-PLGA-PLL nanoparticles loading Cy3-labelled PDGF-BB siRNA by UTMD to rat retina

We investigated the efficacy and safety of ultrasound (US)-targeted microbubble (MB) destruction (UTMD)-enhanced delivery of monomethoxypoly(ethylene glycol)-poly(lactic-co-glycolic acid)-poly-L-lysine (mPEG-PLGA-PLL) nanoparticles (NPs) loading Cy3-labelled platelet-derived growth factor BB (PDGF-BB) siRNA to rat retina in vivo. Eighty Wistar rats were divided into five groups (G). The right eyes, respectively, received an intravitreal injection as follows: normal saline (NS) (G1), NPs and NS (G2), NPs and MBs (G3), NPs and NS (G4) and NPs and MBs (G5). In G4 and G5, the eyes were exposed to US for 5 mins. Twenty-four hours after transfection, the uptake and distribution of Cy3-labelled siRNA in rat retina were observed by fluorescent microscope. The percentage of Cy3- labelled siRNA-positive cells was evaluated by flow cytometer. The levels of PDGF-BB mRNA in retinal pigment epithelium (RPE) cells and secreted PDGF-BB proteins were also measured. Hematoxylin and eosin staining and frozen sections were used to observe tissue damage. Our results showed that the number of Cy3-labelled siRNApositive cells in G5 was significantly higher than those of the other groups (P less than 0.05 for all comparisons). The maximum efficiency of siRNA uptake in neural retina was 18.22 +/_ 1.67%. In G4 and G5, a small number of Cy3- labelled siRNA-positive cells were also detected in the pigmented cell layer of the retina. NPs loading siRNA delivered with UTMD could more effectively down-regulate the mRNA and protein expression of PDGF-BB than NPs plus US (P=0.014 and P=0.007, respectively). Histology showed no evident tissue damage after UTMDmediated NPs loading siRNA transfection. UTMD could be used safely to enhance the delivery of mPEG-PLGAPLL NPs loading siRNA into rat retina.

Enhanced Chemotherapeutic Efficacy of Paclitaxel Nanoparticles Co-delivered with MicroRNA-7 by Inhibiting Paclitaxel-Induced EGFR/ERK pathway Activation for Ovarian Cancer Therapy

Chemotherapy-induced activation of cell survival pathways leads to drug resistance. MicroRNAs (miRNAs) post-transcriptionally regulate gene expression in many biological pathways. Paclitaxel (PTX) is one of the first-line chemotherapy drugs for ovarian cancer, and it induces the activation of the epidermal growth factor receptor (EGFR)/extracellular signal-regulated kinase (ERK) pathway that leads to tumor cell proliferation, survival, invasion, and drug resistance. MicroRNA-7 (miR-7) has the ability to suppress the EGFR/ERK pathway. To sensitize chemotherapy, we developed monomethoxy(poly(ethylene glycol))-poly(d,l-lactide- co-glycolide)-poly(l-lysine) nanoparticles for the simultaneous co-delivery of PTX and miR-7. The resulting PTX/miR-7 nanoparticles (P/MNPs) protect miRNA from degradation, possess a sequential and controlled release of drugs, improve the transfection efficiency of miRNA, decrease the half-maximal inhibitory concentration of PTX, and increase the apoptosis of ovarian cancer cells. The chemotherapeutic efficacy of PTX is prominently enhanced in vitro and in vivo via the inhibition of PTX-induced EGFR/ERK pathway activation by miR-7. Our studies in P/MNPs reveal a novel paradigm for a dual-drug-delivery system of chemotherapeutics and gene therapy in treating cancers.

The synergic antitumor effects of paclitaxel and temozolomide co-loaded in mPEG-PLGA nanoparticles on glioblastoma cells

To get better chemotherapy efficacy, the optimal synergic effect of Paclitaxel (PTX) and Temozolomide (TMZ) on glioblastoma cells lines was investigated. A dual drug-loaded delivery system based on mPEG-PLGA nanoparticles (NPs) was developed to potentiate chemotherapy efficacy for glioblastoma. PTX/TMZ-NPs were prepared with double emulsification solvent evaporation method and exhibited a relatively uniform diameter of 206.3 ± 14.7 nm. The NPs showed sustained release character. Cytotoxicity assays showed the best synergistic effects were achieved when the weight ratios of PTX to TMZ were 1:5 and 1:100 on U87 and C6 cells, respectively. PTX/TMZ-NPs showed better inhibition effect to U87 and C6 cells than single drug NPs or free drugs mixture. PTX/TMZ-NPs (PTX: TMZ was 1:5(w/w)) significantly inhibited the tumor growth in the subcutaneous U87 mice model. These results indicate that coordinate administration of PTX and TMZ combined with NPs is an efficient method for glioblastoma.

FA and cRGD dual modified lipid-polymer nanoparticles encapsulating polyaniline and cisplatin for highly effective chemo-photothermal combination therapy

A combination of chemotherapy and photothermal therapy as a promising strategy has exhibited noticeable therapeutic effect on cancer therapy. To ensure the exertion of synergistic effect on a tumor region, a multifunctional vehicle for selectively delivering therapeutic agent into tumor cells is highly desirable. Thus, folate-poly (ethylene glycol)-distearoylphosphatidylcholine (FA-PEG-DSPE), cRGD [cyclic (Arg-Gly-Asp-D-Phe-Lys)]-PEG-DSPE and lecithin were employed to develop dual modified nanoparticles (FA/cRGD-PNPs) encapsulating polyaniline and cisplatin by a film-ultrasonic dispersion method. The FA/cRGD-PNPs showed a uniform size of 102.7 nm, remarkable stability and monodispersity, and highly localized temperature respond. Compared to chemo or photothermal treatment alone, the combined treatment on cells in vitro significantly suppressed the survival rate of MDA-MB-231 cells (1.87%) and MGC-803 cells (2.37%) treated for 48 h. The results further indicated the induced cell apoptosis rate of MDA-MB-231 cells reached to 92.6% with treatment for 24 h. Hence, our research highlights the great potential in drug delivery and the combination of chemotherapy and photothermal therapy.

Electrostatic interactions between polyglutamic acid and polylysine yields stable polyion complex micelles for deoxypodophyllotoxin delivery

To achieve enhanced physical stability of poly(ethylene glycol)-poly(d,l-lactide) polymeric micelles (PEG-PDLLA PMs), a mixture of methoxy PEG-PDLLA-polyglutamate (mPEG-PDLLA-PLG) and mPEG-PDLLA-poly(l-lysine) (mPEG-PDLLA-PLL) copolymers was applied to self-assembled stable micelles with polyion-stabilized cores. Prior to micelle preparation, the synthetic copolymers were characterized by 1H-nuclear magnetic resonance (NMR) and infrared spectroscopy (IR), and their molecular weights were calculated by 1H-NMR and gel permeation chromatography (GPC). Dialysis was used to prepare PMs with deoxypodophyllotoxin (DPT). Transmission electron microscopy (TEM) images showed that DPT polyion complex micelles (DPT-PCMs) were spherical, with uniform distribution and particle sizes of 36.3±0.8 nm. In addition, compared with nonpeptide-modified DPT-PMs, the stability of DPT-PCMs was significantly improved under various temperatures. In the meantime, the pH sensitivity induced by charged peptides allowed them to have a stronger antitumor effect and a pH-triggered release profile. As a result, the dynamic characteristic of DPT-PCM was retained, and high biocompatibility of DPT-PCM was observed in an in vivo study. These results indicated that the interaction of anionic and cationic charged polyionic segments could be an effective strategy to control drug release and to improve the stability of polymer-based nanocarriers.

Fabrication of self-assembled folate-biotin-quaternized starch nanoparticles as co-carrier of doxorubicin and siRNA

In this paper, the starch was firstly modified by quaternary reagent to obtain cationic starch. Then self-assembled folate-biotin-quaternized starch nanoparticles were prepared by a one-pot synthesis via N,N'-dicyclohexylcarbodiimide/N-hydroxysuccinimide/4-dimethylaminopyridine-mediated esterification reaction. The physicochemical properties of the prepared folate-biotin-quaternized starch nanoparticles were characterized. The average diameter of folate-biotin-quaternized starch nanoparticles was 109 nm with polydispersity index of 0.183 and zeta potential of 28.59 mV. The folate-biotin-quaternized starch nanoparticles were used as co-carrier of siRNA and doxorubicin with satisfactory drug loading capacity (6.98%) and encapsulation efficiency (69.66 %), and siRNA could be efficiently encapsulated at 40/1 weight ratio of doxorubicin/folate-biotin-quaternized starch nanoparticles to siRNA. The folate-biotin-quaternized starch nanoparticles could effectively protect siRNA from degradation of serum RNAase for up to 48 h. The release characteristics of doxorubicin and siRNA from folate-biotin-quaternized starch nanoparticles were studied in different pH environment and the release behaviors of two drugs were all pH sensitive. The folate-biotin-quaternized starch nanoparticles as a potential co-carrier of anticancer agents and gene drugs was expected to achieve future practical application in vitro and in vivo.

A Novel MPEG-PDLLA-PLL Copolymer for Docetaxel Delivery in Breast Cancer Therapy

Satisfactory drug loading capacity and stability are the two main factors that determine the anti-cancer performance. In general, the stability of the micelles is reduced when the drug loading (DL) is increased. Therefore, it was a challenge to have high drug loading capacity and good stability. In this study, we introduced a hydrophilic poly (L-Lysine) (PLL) segment with different molecular-weights into the monomethoxy poly (ethylene glycol)-poly (D, L-lactide) (MPEG-PDLLA) block copolymer to obtain a series of novel triblock MPEG-PDLLA-PLL copolymers. We found that the micelles formed by a specific MPEG2k-PDLLA4k-PLL1k copolymer could encapsulate docetaxel (DTX) with a satisfactory loading capacity of up to 20% (w/w) via the thin film hydration method, while the stability of drug loaded micellar formulation was still as good as that of micelles formed by MPEG2k-PDLLA1.7k with drug loading of 5% (w/w). The results from computer simulation study showed that compared with MPEG2k-PDLLA1.7k, the molecular chain of MPEG2k-PDLLA4k-PLL1k could form a more compact funnel-shaped structure when interacted with DTX. This structure favored keeping DTX encapsulated in the copolymer molecules, which improved the DL and stability of the nano-formulations. The in vitro and in vivo evaluation showed that the DTX loaded MPEG2k-PDLLA4k-PLL1k (DTX/MPEG2k-PDLLA4k-PLL1k) micelles exhibited more efficiency in tumor cell growth inhibition. In conclusion, the MPEG2k-PDLLA4k-PLL1k micelles were much more suitable than MPEG2k-PDLLA1.7k for DTX delivery, and then the novel nano-formulations showed better anti-tumor efficacy in breast cancer therapy.

Nanoformulations for combination or cascade anticancer therapy

Nanoparticle drug formulations have been extensively investigated, developed, and in some cases, approved by the Food and Drug Administration (FDA). Synergistic combinations of drugs having distinct tumor-inhibiting mechanisms and non-overlapping toxicity can circumvent the issue of treatment resistance and may be essential for effective anti-cancer therapy. At the same time, co-delivery of a combined regimen by a single nanocarrier presents a challenge due to differences in solubility, molecular weight, functional groups and encapsulation conditions between the two drugs. This review discusses cellular and microenvironment mechanisms behind treatment resistance and nanotechnology-based solutions for effective anti-cancer therapy. Co-loading or cascade delivery of multiple drugs using of polymeric nanoparticles, polymer-drug conjugates and lipid nanoparticles will be discussed along with lipid-coated drug nanoparticles developed by our lab and perspectives on combination therapy.

Polyethylene glycol-poly(ε-benzyloxycarbonyl-l-lysine)-conjugated VEGF siRNA for antiangiogenic gene therapy in hepatocellular carcinoma

A polyethylene glycol-poly(ε-benzyloxycarbonyl-l-lysine) (PEG-SS-PLL) block copolymer based on a disulfide-linked, novel biodegradable catiomer bearing a PEG-sheddable shell was developed to avoid "PEG dilemma" in nanoparticle intracellular tracking of PEG-PLL where PEG was nondegradable. However, PEG-SS-PLL catiomers have not been used to deliver small interfering VEGF RNA (siVEGF) in antiangiogenesis gene therapy. In this study, we aimed to investigate whether this novel biodegradable catiomer can deliver siVEGF into cancer cells and at the same time have an antitumor effect in a xenograft mouse model. It was found that PEG-SS-PLL efficiently delivered siVEGF with negligible cytotoxicity, and significantly decreased the expression of VEGF at both the messenger-RNA and protein levels both in vitro and in vivo, and thus tumor growth was inhibited. Our findings demonstrated that PEG-SS-PLL/siVEGF could potentially be applied to antiangiogenesis gene therapy for hepatocellular carcinoma.

Prevention of Oxidized Low Density Lipoprotein-Induced Endothelial Cell Injury by DA-PLGA-PEG-cRGD Nanoparticles Combined with Ultrasound

In general, atherosclerosis is considered to be a form of chronic inflammation. Dexamethasone has anti-inflammatory effects in atherosclerosis, but it was not considered for long-term administration on account of a poor pharmacokinetic profile and adverse side effects. Nanoparticles in which drugs can be dissolved, encapsulated, entrapped or chemically attached to the particle surface have abilities to incorporate dexamethasone and to be used as controlled or targeted drug delivery system. Long circulatory polymeric nanoparticles present as an assisting approach for controlled and targeted release of the encapsulated drug at the atherosclerotic site. Polymeric nanoparticles combined with ultrasound (US) are widely applied in cancer treatment due to their time applications, low cost, simplicity, and safety. However, there are few studies on atherosclerosis treatment using polymeric nanoparticles combined with US. In this study, targeted dexamethasone acetate (DA)-loaded poly (lactide-glycolide)-polyethylene glycol-cRGD (PLGA-PEG-cRGD) nanoparticles (DA-PLGA-PEG-cRGD NPs) were prepared by the emulsion-evaporation method using cRGD modified PLGA-PEG polymeric materials (PLGA-PEG-cRGD) prepared as the carrier. The average particle size of DA-PLGA-PEG-cRGD NPs was 221.6 ± 0.9 nm. Morphology of the nanoparticles was spherical and uniformly dispersed. In addition, the DA released profiles suggested that ultrasound could promote drug release from the nanocarriers and accelerate the rate of release. In vitro, the cellular uptake process of fluorescein isothiocyanate (FITC)@DA-PLGA-PEG-cRGD NPs combined with US into the damaged human umbilical vein endothelial cells (HUVECs) indicated that US promoted rapid intracellular uptake of FITC@DA- PLGA-PEG-cRGD NPs. The cell viability of DA-PLGA-PEG-cRGD NPs combined with US reached 91.9% ± 0.2%, which demonstrated that DA-PLGA-PEG-cRGD NPs combined with US had a positive therapeutic effect on damaged HUVECs. Overall, DA-PLGA-PEG-cRGD NPs in combination with US may provide a promising drug delivery system to enhance the therapeutic effects of these chemotherapeutics at the cellular level.

PLGA-based dual targeted nanoparticles enhance miRNA transfection efficiency in hepatic carcinoma

Hepatic carcinoma (HCC) is a lethal disease associated with high morbidity and poor prognosis. Recently years, gene therapies have offered novel modalities to improve the prognosis of HCC patients. MicroRNA-99a (miR-99a) is frequently down-regulated in HCC, where it acts as a tumor suppressor. Therefore, we constructed monomethoxy (polyethylene glycol)-poly(D,L-lactide-co-glycolide)-poly(L-lysine)-lactobionic acid- anti-vascular endothelial growth factor antibody (mPEG-PLGA-PLL-LA/VEGFab or PEAL-LA/VEGFab) nanoparticles (NPs) with highly specific targeting properties as carriers to restore the expression of miR-99a both in vitro and in vivo, to inhibit HCC progression. In vitro, PEAL-LA/VEGFab NPs showed more efficient delivery of miR-99a to HepG2 cells than the conventional transfection reagent Lipofectamine^TM2000 (Lip2000). The higher delivery efficiency associated with PEAL-LA/VEGFab NPs consequently resulted in down-regulation of target genes and suppression of the proliferation, migration and invasion of HepG2 cells. In vivo, miR-99a-PEAL-LA/VEGFab NPs inhibited tumor xenograft growth in HCC-bearing mice without causing obvious systemic toxicity. Our results demonstrate that PEAL-LA/VEGFab NPs selectively and effectively deliver miR-99a to HCC cells based on the double-targeting character of these nanoparticles, thereby offering potential for translation into effective clinical therapies for HCC.

Imaging the pharmacology of nanomaterials by intravital microscopy: Toward understanding their biological behavior

Therapeutic nanoparticles (NPs) can deliver cytotoxic chemotherapeutics and other drugs more safely and efficiently to patients; furthermore, selective delivery to target tissues can theoretically be accomplished actively through coating NPs with molecular ligands, and passively through exploiting physiological "enhanced permeability and retention" features. However, clinical trial results have been mixed in showing improved efficacy with drug nanoencapsulation, largely due to heterogeneous NP accumulation at target sites across patients. Thus, a clear need exists to better understand why many NP strategies fail in vivo and not result in significantly improved tumor uptake or therapeutic response. Multicolor in vivo confocal fluorescence imaging (intravital microscopy; IVM) enables integrated pharmacokinetic and pharmacodynamic (PK/PD) measurement at the single-cell level, and has helped answer key questions regarding the biological mechanisms of in vivo NP behavior. This review summarizes progress to date and also describes useful technical strategies for successful IVM experimentation.

Templated fabrication of pH-responsive poly(l-glutamic acid) based nanogels via surface-grafting and macromolecular crosslinking

A novel class of pH-responsive poly(l-glutamic acid)/chitosan (PLGA/CS) nanogels was fabricated by a templating approach, combined with a “grafting from” method and intermacromolecular crosslinking technique.

Enhanced therapeutic effect of Adriamycin on multidrug resistant breast cancer by the ABCG2-siRNA loaded polymeric nanoparticles assisted with ultrasound

The overexpression of the breast cancer resistance protein (ABCG2) confers resistance to Adriamycin (ADR) in breast cancer. The silencing of ABCG2 using small interfering RNA (siRNA) could be a promising approach to overcome multidrug resistance (MDR) in cancer cells. To deliver ABCG2-siRNA effectively into breast cancer cells, we used mPEG-PLGA-PLL (PEAL) nanoparticles (NPs) with ultrasound-targeted microbubble destruction (UTMD). PEAL NPs were prepared with an emulsion-solvent evaporation method. The NPs size was about 131.5 ± 6.5 nm. The siRNA stability in serum was enhanced. The intracellular ADR concentration increased after the introduction of siRNA-loaded NPs. After intravenous injection of PEAL NPs in tumor-bearing mice, the ABCG2-siRNA-loaded NPs with UTMD efficiently silenced the ABCG2 gene and enhanced the ADR susceptibility of MCF-7/ADR (ADR resistant human breast cancer cells). The siRNA-loaded NPs with UTMD + ADR showed better tumor inhibition effect and good safety in vivo. These results indicate that ADR-chemotherapy in combination with ABCG2-siRNA is an attractive strategy to treat breast cancer.