Inhibition of murine breast cancer growth and metastasis by survivin-targeted siRNA using disulfide cross-linked linear PEI

Therapeutic delivery of siRNA for the management of breast cancer and triple-negative breast cancer

Breast cancer is the leading cause of cancer-related deaths among women globally. The difficulties with anticancer medications, such as ineffective targeting, larger doses, toxicity to healthy cells and side effects, have prompted attention to alternate approaches to address these difficulties. RNA interference by small interfering RNA (siRNA) is one such tactic. When compared with chemotherapy, siRNA has several advantages, including the ability to quickly modify and suppress the expression of the target gene and display superior efficacy and safety. However, there are known challenges and hurdles that limits their clinical translation. Decomposition by endonucleases, renal clearance, hydrophilicity, negative surface charge, short half-life and off-target effects of naked siRNA are obstacles that hinder the desired biological activity of naked siRNA. Nanoparticulate systems such as polymeric, lipid, lipid-polymeric, metallic, mesoporous silica nanoparticles and several other nanocarriers were used for effective delivery of siRNA and to knock down genes involved in breast cancer and triple-negative breast cancer. The focus of this review is to provide a comprehensive picture of various strategies utilized for delivering siRNA, such as combinatorial delivery, development of modified nanoparticles, smart nanocarriers and nanocarriers that target angiogenesis, cancer stem cells and metastasis of breast cancer.

Tet1 peptide and zinc (II)-adenine multifunctional module functionalized polycations as efficient siRNA carriers for Parkinson's disease

A bioreducible Zn (II)-adenine multifunctional module (BS) and Tet1 peptide were used to modify low-molecular-weight PEI3.5k (polyethyleneimine with molecular weight of 3.5 kDa)into a siRNA vector Zn-PB-T with high transfection efficiency in neurons. A GSH-responsive breakable disulfide spacer was introduced into BS to realize the controlled release of siRNA from the polyplexes in cytoplasm. Zn-PB showed >90% transfection rates in multiple cell lines (3 T3, HK-2, HepG2, 293 T, HeLa, PANC-1)，and 1.8-folds higher EGFP knockdown rates than commercial Lipo2k in normal cell line 293 T and cancer cell line HepG2. And Zn-PB-T1 showed 4.7-4.9- and 8.0-8.1-folds higher transfection efficiency comparing to commercial Lipo2k and PEI25k (polyethyleneimine with molecular weight of 25 kDa) in PC12 cells respectively, 2.1-fold EGFP gene silencing efficiency (96.6% EGFP knockdown rates) superior to commercial Lipo2k in neurons. In Parkinson's model, Zn-PB-T1/SNCA-siRNA can effectively protect neurons against MPP+-induced cell death and apoptosis, increasing the cell survival rate to 84.6% and reducing the cell apoptosis rate to 10.8%. This work demonstrated the promising application prospects of the resulting efficient siRNA carriers in siRNA-mediated gene therapy of Parkinson's disease.

PEI-based functional materials: Fabrication techniques, properties, and biomedical applications

Cationic polymers have recently attracted considerable interest as research breakthroughs for various industrial and biomedical applications. They are particularly interesting due to their highly positive charges, acceptable physicochemical properties, and ability to undergo further modifications, making them attractive candidates for biomedical applications. Polyethyleneimines (PEIs), as the most extensively utilized polymers, are one of the valuable and prominent classes of polycations. Owing to their flexible polymeric chains, broad molecular weight (MW) distribution, and repetitive structural units, their customization for functional composites is more feasible. The specific beneficial attributes of PEIs could be introduced by purposeful functionalization or modification, long service life, biocompatibility, and distinct geometry. Therefore, PEIs have significant potential in biotechnology, medicine, and bioscience. In this review, we present the advances in PEI-based nanomaterials, their transfection efficiency, and their toxicity over the past few years. Furthermore, the potential and suitability of PEIs for various applications are highlighted and discussed in detail. This review aims to inspire readers to investigate innovative approaches for the design and development of next-generation PEI-based nanomaterials possessing cutting-edge functionalities and appealing characteristics.

Tumor-Associated Macrophages Regulating a Polymer Nanoplatform for Synergistic Treatment of Breast Tumors

Tumor-associated macrophages (TAMs) play a critical role in tumor progression and metastasis. Modulation of TAM polarization is one of the most effective strategies to change the immunosuppressive tumor microenvironment (TME). In this study, organic polymer nanoparticles (CPHT) were prepared using hyaluronic acid (HA)-conjugated disulfide-bonded polyethylene imide (PEIS) as a carrier through a self-assembly strategy. These nanoparticles were modified by transferrin (Tf) and loaded with chlorin e6 (Ce6). The results showed that CPHT had good dispersion with a particle size of about 30 nm. CPHT gradually disintegrated under the exposure with a high concentration of glutathione (GSH) in tumor cells, proving the possibility for the controlled release of Ce6 and photodynamic therapy. An in vitro test showed that the uptake of CPHT in tumor cells was mediated by both HA and Tf, indicating the active tumor-targeting capacity of CPHT. CPHT significantly downregulated the ratio of CD206/CD86 and triggered the upregulation of immune factors such as TNF-α and iNOS, suggesting the repolarization of TAMs. We also found that CPHT effectively induced ferroptosis in tumor cells through lipid peroxide accumulation, GSH depletion, and downregulation of lipid peroxidase (GPX4) expression. Animal experiments confirmed that CPHT not only effectively inhibited the growth of tumors in situ but also significantly decelerated the growth of the distal tumor. Elevated levels of CD86 and IFN-γ and decreased expression of CD206 were observed at the tumor sites post CPHT treatment. These results confirmed the value of CPHT as a multifunctional nanoplatform that can tune the TME and provide new hope for tumor treatment.

siRNA and targeted delivery systems in breast cancer therapy

Recently, nucleic acid drugs have been considered as promising candidates in treatment of various diseases, especially cancer. Because of developing resistance to conventional chemotherapy, use of genetic tools in cancer therapy appears inevitable. siRNA is a RNAi tool with capacity of suppressing target gene. Owing to overexpression of oncogenic factors in cancer, siRNA can be used for suppressing those pathways. This review emphasizes the function of siRNA in treatment of breast tumor. The anti-apoptotic-related genes including Bcl-2, Bcl-xL and survivin can be down-regulated by siRNA in triggering cell death in breast cancer. STAT3, STAT8, Notch1, E2F3 and NF-κB are among the factors with overexpression in breast cancer that their silencing by siRNA paves the way for impairing tumor proliferation and invasion. The oncogenic mechanisms in drug resistance development in breast tumor such as lncRNAs can be suppressed by siRNA. Furthermore, siRNA reducing P-gp activity can increase drug internalization in tumor cells. Because of siRNA degradation at bloodstream and low accumulation at tumor site, nanoplatforms have been employed for siRNA delivery to suppress breast tumor progression via improving siRNA efficacy in gene silencing. Development of biocompatible and efficient nanostructures for siRNA delivery can make milestone progress in alleviation of breast cancer patients.

Current Advancements in Self-assembling Nanocarriers-Based siRNA Delivery for Cancer Therapy

Different therapeutic practices for treating cancers have significantly evolved to compensate and/or overcome the failures in conventional methodologies. The demonstrated potentiality in completely inhibiting the tumors and in preventing cancer relapse has made nucleic acids therapy (NAT)/gene therapy as an attractive practice. This has been made possible because NAT-based cancer treatments are highly focused on the fundamental mechanisms - i.e., silencing the expression of oncogenic genes responsible for producing abnormal proteins (via messenger RNAs (mRNAs)). However, the future clinical translation of NAT is majorly dependent upon the effective delivery of the exogenous nucleic acids (especially RNAs - e.g., short interfering RNAs (siRNAs) - herein called biological drugs). Moreover, nano-based vehicles (i.e., nanocarriers) are involved in delivering them to prevent degradation and undesired bioaccumulation while enhancing the stability of siRNAs. Herein, we have initially discussed about three major types of self-assembling nanocarriers (liposomes, polymeric nanoparticles and exosomes). Later, we have majorly reviewed recent developments in non-targeted/targeted nanocarriers for delivery of biological drugs (individual/dual) to silence the most important genes/mRNAs accountable for inducing protein abnormality. These proteins include polo-like kinase 1 (PLK1), survivin, vascular endothelial growth factor (VEGF), B-cell lymphoma/leukaemia-2 (Bcl-2) and multi-drug resistance (MDR). Besides, the consequent therapeutic effects on cancer growth, invasion and/or metastasis have also been discussed. Finally, we have comprehensively reviewed the improvements achieved in the cutting-edge cancer therapeutics while delivering siRNAs in combination with clinically approved chemotherapeutic drugs.

In Vivo Delivery of siRNAs Targeting EGFR and BRD4 Expression by Peptide-Modified Redox Responsive PEG-PEI Nanoparticles for the Treatment of Triple-Negative Breast Cancer

The study aims to investigate the in vivo distribution, antitumor effect, and safety of cell membrane-penetrating peptide-modified disulfide bond copolymer nanoparticles loaded with small-interfering RNA (siRNA) targeting epidermal growth factor receptor (EGFR) and bromodomain-containing protein 4 (BRD4) in triple-negative breast cancer (TNBC). Polyethylene glycol disulfide bond-linked polyethylenimine (PEG-SS-PEI) was modified with peptides GALA and CREKA and used as vectors to prepare siRNA nanoparticles. The GALA- and CREKA-modified PEG-SS-PEI nanoparticles (GC-NPs) were prepared by mixing siEGFR and siBRD4 (1:1) with GALA-PEG-SS-PEI and CREKA-PEG-SS-PEI (1:1) in an aqueous solution at an N/P ratio of 30:1. Nanoparticles loaded with scrambled siRNA were prepared with the same method. The gene silencing effect on EGFR and BRD4 in vitro was evaluated by Western blotting analysis. TNBC xenograft models were established by subcutaneous injection of MDA-MB-231 cells into female nude mice. At 1, 3, 6, 12, and 24 h after administration of five formulations of Cy5-siRNA (133 μg/10 g) via the tail vein, the mice were observed and imaged for a biodistribution study using an in vivo imaging system. In the pharmacodynamics experiment, tumor-bearing mice were treated with respective siRNA preparations at a dose of 133 μg/10 g for 18 days, and the body weight and tumor size were recorded every other day. The protein expression levels of EGFR, p-EGFR, PI3K, p-PI3K, Akt, p-Akt, BRD4, and c-Myc were determined using Western blotting analysis. Hematological and serum biochemical parameters, organ indices, and HE staining results for the heart, liver, spleen, lung, and kidney were analyzed to evaluate the safety of the nanoparticles. GC-NPs loaded with siEGFR and siBRD4 significantly inhibited the expression of EGFR and BRD4 in vitro. The strongest fluorescence signals were observed in the GC-NP group, especially in tumors, indicating the excellent tumor-targeted delivery of GC-NPs we constructed. Tumor growth was significantly inhibited in the GC-NP-treated group, and the expression of EGFR, p-EGFR, PI3K, p-PI3K, Akt, p-Akt, BRD4, and c-Myc in the tumors decreased by 71%, 68%, 61%, 68%, 48%, 58%, 59%, and 74% compared to the control group, respectively. There was no significant change in hematological parameters, biochemical indices, or tissue morphology in GC-NP-treated mice. SiRNA cotargeting EGFR and BRD4 delivered by GALA- and CREKA-modified PEG-SS-PEI had favorable antitumor effects in vivo toward TNBC with tumor-targeting efficacy and good biocompatibility.

Application of Non-Viral Vectors in Drug Delivery and Gene Therapy

Vectors and carriers play an indispensable role in gene therapy and drug delivery. Non-viral vectors are widely developed and applied in clinical practice due to their low immunogenicity, good biocompatibility, easy synthesis and modification, and low cost of production. This review summarized a variety of non-viral vectors and carriers including polymers, liposomes, gold nanoparticles, mesoporous silica nanoparticles and carbon nanotubes from the aspects of physicochemical characteristics, synthesis methods, functional modifications, and research applications. Notably, non-viral vectors can enhance the absorption of cargos, prolong the circulation time, improve therapeutic effects, and provide targeted delivery. Additional studies focused on recent innovation of novel synthesis techniques for vector materials. We also elaborated on the problems and future research directions in the development of non-viral vectors, which provided a theoretical basis for their broad applications.

Integrating disulfides into a polyethylenimine gene carrier selectively boosts significant transfection activity in lung tissue enabling robust IL-12 gene therapy against metastatic lung cancers

Bioreducible polyethylenimines (SSPEIs) are promising non-viral carriers for cancer gene therapy. However, the availability of significant gene transfection activity by SSPEIs remains a challenge. Herein, an essential step was taken to ascertain whether or not the disulfide bonds of SSPEIs play a critical role in promoting significant gene transfection activity in different tissues. Initially, a disulfide-linked linear polyethylenimine (denoted as SSLPEI) consisting of one 5.0 kDa LPEI main chain and three disulfide-linked 5.7 kDa LPEI grafts was designed and prepared to possess similar molecular weight with commercialized 25 kDa LPEI as a positive control. The SSLPEI could induce superior in vitro transfection activity in different cells to the LPEI control as well as low cytotoxicity. Notably, such enhanced in vitro transfection effect by the SSLPEI was more marked in type-II alveolar epithelial cells compared to different cancer cells. In a Balb/c nude mouse model bearing SKOV-3 tumor, the SSLPEI caused parallel level of transgene expression with the LPEI control in the tumor but significantly higher level in the mouse lung. Furthermore, the SSLPEI and LPEI groups afforded an identical antitumor efficacy against the SKOV-3 tumor via intravenous delivery of a shRNA for silencing VEGF expression in the tumor. However, via intravenous delivery of an interleukin-12 (IL-12) gene into metastatic lung cancers in a C57BL/6 mouse model, the SSLPEI group exerted markedly higher IL-12 expression level in the mouse lung and peripheral blood as compared to the LPEI group, thereby boosting IL-12 immunotherapy against the lung metastasis with longer medium survival time. The results of this work elicit that the disulfide bonds of SSPEIs play a pivotal role in enhancing gene transfection activity selectively in the lung tissue rather than solid tumor, enabling high translational potential of SSPEIs for non-viral gene therapy against metastatic lung cancers.

Multifunctional polymeric micellar nanomedicine in the diagnosis and treatment of cancer

Polymeric micelles are a prevalent topic of research for the past decade, especially concerning their fitting ability to deliver drug and diagnostic agents. This delivery system offers outstanding advantages, such as biocompatibility, high loading efficiency, water-solubility, and good stability in biological fluids, to name a few. The multifunctional polymeric micellar architect offers the added capability to adapt its surface to meet the looked-for clinical needs. This review cross-talks the recent reports, proof-of-concept studies, patents, and clinical trials that utilize polymeric micellar family architectures concerning cancer targeted delivery of anticancer drugs, gene therapeutics, and diagnostic agents. The manuscript also expounds on the underlying opportunities, allied challenges, and ways to resolve their bench-to-bedside translation for allied clinical applications.

Design of a novel electrospun PVA platform for gene therapy applications using the CHAT peptide

The electrospinning of polymers has previously shown excellent potential for localised gene therapy. Thus, it was proposed that for the first time, the cell-penetrating CHAT peptide could be utilised to deliver DNA via electrospun nanofibres for localised gene therapy treatment. CHAT is an effective delivery system that encapsulates pDNA to form nanoparticles with the physicochemical characteristics for cellular uptake and protein generation. In this study, the production of smooth, bead-free PVA nanofibres by electrospinning was optimised through a Design of Experiments approach. Bead-free PVA nanofibres were consistently produced using the optimised parameters as follows: applied voltage (8 kV); collector-emitter distance (8 cm); polymer flow rate (4 µL/min); polymer concentration (9 wt% polymer); PVA M_W (146-180 kDa). PVA nanofibres were subsequently crosslinked in 1 vol% glutaraldehyde in methanol to confer stability under aqueous conditions with minimal change to morphology, and no compromise to biocompatibility. Nanoparticles of CHAT/pDNA were synthesised and incorporated into the crosslinked nanofibres via soak-loading. Evaluation studies indicated that 100% of the loaded cargo was released within 48 h from the nanofibres. Furthermore, the released pDNA retained structural integrity and functionality as confirmed by gel electrophoresis and transfection studies in NCTC-929 fibroblast cells. Taken together, this data demonstrates that delivery of CHAT/pDNA nanoparticles from electrospun PVA nanofibres represents a solution for localised gene therapy.

Redox stimulus disulfide conjugated polyethyleneimine as a shuttle for gene transfer

Redox-responsive cationic polymers have gained considerable attention in gene delivery due to low cytotoxicity and spatio-temporal release of DNA into the cells. Here, we reported the synthesis of reducible disulfide conjugated polyethyleneimine (1.8 kDa) (denoted as SS-PEI) and its application to transfer pEGFP-ZNF580 plasmid (pZNF580) into EA.hy926 cell. This reducible SS-PEI polymer was prepared by one-step polycondensation reaction of low molecular weight PEI with bis-(p-nitrophenyl)-3,3'-dithiodipropionate. The SS-PEI successfully condensed pZNF580 into nano-sized complexes (170 ± 1.5 nm to 255 ± 1.6 nm) with zeta potentials of 3 ± 0.4 mV to 17 ± 0.9 mV. The complexes could be triggered to release pZNF580 when exposed to the reducing environment of 5 mM dithiothreitol. Besides, the SS-PEI exhibited low cytotoxicity. In vitro transfection results showed that SS-PEI exhibited good transfection efficiency comparable to PEI25kDa. Thus, the SS-PEI could act as an reducible gene carrier with good transfection efficiency and low cytotoxicity.

Nanoparticle Delivery of CD147 Antagonistic Peptide-9 Protects against Acute Ischemic Brain Injury and tPA-Induced Intracerebral Hemorrhage in Mice

CD147 has emerged as a potential therapeutic target in many human diseases. We have demonstrated that inhibition of CD147 using its function-blocking antibody ameliorates acute ischemic brain injury and promotes long-term functional recovery in mice. Recently, peptide-nanoparticle conjugates have emerged as powerful tools for biomedical applications. The present study aimed to investigate the therapeutic potential of CD147 antagonist peptide-9 (AP9) in acute ischemic stroke in mice using nanomaterial as the drug delivery vehicles. AP9-conjugated nanoparticles (APN), with an average size of about 40 nm, were fabricated by maleimide linkage and characterized using dynamic light scattering and transmission electron microscopy. We found that APN specifically bound to CD147 in cultured mouse brain endothelial cells (bEnd.3) and to ischemia-induced CD147 in mouse cerebral microvessels. Using a mouse model of transient middle cerebral artery occlusion (tMCAO), we demonstrated, for the first time, that systemic delivery of APN (2.5 mg/kg, I.V.) initiated at 1 h after tMCAO significantly reduced brain infarct size, improved functional outcome, and attenuated delayed (5 h after tMCAO) tPA-induced intracerebral hemorrhage in acute ischemic stroke. These protective effects were associated with profound inhibition of MMP-9 and MMP-3 in both ischemic brain and plasma. In conclusion, the CD147 antagonist peptide-9 represents a potentially promising therapeutic candidate for the treatment of ischemic stroke.

Construction and anti-tumor activities of disulfide-linked docetaxel-dihydroartemisinin nanoconjugates

Co-delivery of anti-tumor agents with outstanding stimulus-triggered drug release in tumor cells, especially with the aid of nanotechnology, provided the possibility to enhance delivery efficiency for targeting tumor cells and antitumor efficacy. In this paper, docetaxel-dihydroartemisinin nanoconjugates linked by disulfide bond were designed to increase co-delivery and anti-tumor efficacy. Docetaxel and dihydroartemisinin were synthesized using two-step reaction and furtherly assembled to nanoconjugates. Nanoprescription was optimized to evaluate its physicochemical properties. In vitro anti-tumor activities of nanoformulation were assessed by MTT. The flow cytometry was adopted to analyze cell apoptosis and cell cycle arrest. The wound healing assay was used to evaluate antimigratory-property. In vivo pharmacokinetic and pharmacodynamic studies were investigated in rats and 4T1 bearing Balb/c mice model after intravenous injection, respectively. The chemical structure of conjugate was confirmed. The prepared nanoparticles possessed uniform size distribution (172.10 ± 1.70 nm, PDI 0.05 ± 0.01), was stable during storage period, sustained release profiles and sensitive reduction responsiveness. MTT assay indicated that the toxicity of nanoconjugates was slightly weak. Flow cytometry studies showed that nanoconjugates could promote early apoptosis significantly and mainly arose from G₀/G₁ phase. The wound healing assay provided an obvious antimetastatic potential of nanoparticles in 4T1 cells. The result of pharmacokinetic study suggested that nanoconjugates exhibited higher exposure levels. In vivo pharmacodynamic research showed that mice treated with docetaxel-dihydroartemisinin nanoconjugates had lower systemic toxicity and higher survival ratio than those of control groups. This potential of nanoconjugates was developed as a novel nanoplateform to treat tumor.

RGD-decorated cholesterol stabilized polyplexes for targeted siRNA delivery to glioblastoma cells

The development of an effective and safe treatment for glioblastoma (GBM) represents a significant challenge in oncology today. Downregulation of key mediators of cell signal transduction by RNA interference is considered a promising treatment strategy but requires efficient, intracellular delivery of siRNA into GBM tumor cells. Here, we describe novel polymeric siRNA nanocarriers functionalized with cRGD peptide that mediates targeted and efficient reporter gene silencing in U87R invasive human GBM cells. The polymer was synthesized via RAFT copolymerization of N-(2-hydroxypropyl)-methacrylamide (HPMA) and N-acryloxysuccinimide (NAS), followed by post-polymerization modification with cholesterol for stabilization, cationic amines for siRNA complexation, and azides for copper-free click chemistry. The novel resultant cationic polymer harboring a terminal cholesterol group, self-assembled with siRNA to yield nanosized polyplexes (~ 40 nm) with good colloidal stability at physiological ionic strength. Post-modification of the preformed polyplexes with PEG-cRGD end-functionalized with bicyclo[6.1.0]nonyne (BCN) group resulted in enhanced cell uptake and increased luciferase gene silencing in U87R cells, compared to polyplexes lacking cRGD-targeting groups.

Glycyrrhetinic acid modified and pH-sensitive mixed micelles improve the anticancer effect of curcumin in hepatoma carcinoma cells

Curcumin (CUR), a natural polyphenolic compound existing in plants, exhibits anticancer potential in inhibiting the growth of various types of human cancer. However, the poor aqueous solubility and low bioavailability limit its clinical applications. pH-sensitive macromolecule F68-acetal-PCL (FAP) and active targeting macromolecule F68-glycyrrhetinic acid (FGA) were designed to fabricate mixed micelles for efficient delivery of CUR. The thin film hydration method was used to prepare CUR loaded mixed (MIX/CUR) micelles. The drug loading rate (DL) of MIX/CUR micelles was 6.31 ± 0.92%, which remained stable for 15 days at 4 °C. The particle size and zeta potential of the MIX/CUR micelles were 91.06 ± 1.37 nm and -9.79 ± 0.47 mV, respectively. The MIX/CUR micelles exhibited pH sensitivity in a weak acid environment, and showed rapid particle size variation and drug release. In addition, in vitro tests demonstrated that MIX/CUR micelles induced higher cytotoxicity and apoptosis than free CUR, non-pH-sensitive F68-PCL (FBP)/CUR micelles and pH-sensitive FAP/CUR micelles in SMMC7721 and Hepa1-6 cells. Besides, mixed micelles were more effective than FBP and FAP micelles in a cell uptake experiment, which was medicated by a GA receptor. All in all, these results indicated that MIX/CUR micelles could be regarded as an ideal drug administration strategy against hepatoma carcinoma cells.

Polycations for Gene Delivery: Dilemmas and Solutions

Gene therapy has been a promising strategy for treating numerous gene-associated human diseases by altering specific gene expressions in pathological cells. Application of nonviral gene delivery is hindered by various dilemmas encountered in systemic gene therapy. Therefore, solutions must be established to address the unique requirements of gene-based treatment of diseases. This review will particularly highlight the dilemmas in polycation-based gene therapy by systemic treatment. Several promising strategies, which are expected to overcome these challenges, will be briefly reviewed. This review will also explore the development of polycation-based gene delivery systems for clinical applications.

Vinorelbine cationic liposomes modified with wheat germ agglutinin for inhibiting tumor metastasis in treatment of brain glioma

Glioma is the most common primary malignant brain tumor with a poor prognosis. The application of chemotherapeutic drugs is limited due to the existence of blood-brain barrier and serious side effects. Liposomes have been proven to be a stable and useful drug delivery system for tumors. In this paper, WGA (wheat germ agglutinin) modified vinorelbine cationic liposomes had been successfully constructed for treating glioma. In the liposomes, WGA was modified on the liposomal surface for crossing the blood-brain barrier and increasing the targeting effects, 3-(N-(N', N'-dimethylaminoethane) carbamoyl) cholesterol (DC-Chol) was used as cationic material and vinorelbine was encapsulated in the aqueous core of liposomes to inhibit tumor metastasis and kill tumor cells. Studies were performed on C6 cells in vitro and were verified in brain glioma-bearing mice in vivo. Results in vitro demonstrated that the targeting liposomes could induce C6 cells apoptosis, promote drugs across the blood-brain barrier, inhibit the metastasis of tumor cells and increase targeting effects to tumor cells. Meanwhile, action mechanism studies showed that the targeting liposomes could down-regulate PI3K, MMP-2, MMP-9 and FAK to inhibit tumor metastasis. Results in vivo exhibited that the targeting liposomes displayed an obvious antitumor efficacy by accumulating selectively in tumor site and exhibited low toxicity to blood system and major organs. Hence, WGA modified vinorelbine cationic liposomes might provide a safe and efficient therapy strategy for glioma.

Aromatic Thioacetal-Bridged ROS-Responsive Nanoparticles as Novel Gene Delivery Vehicles

In this report, a series of polycations are designed and synthesized by conjugating reactive oxygen species (ROS)-responsive thioacetal-linkers to low molecular weight (LMW) polyethylenimine (PEI) via ring-opening polymerization. Their structure⁻activity relationships (SARs) as gene delivery vectors are systematically studied. Although the MWs of the target polymers are only ~9 KDa, they show good DNA binding ability. The formed polyplexes, which are stable toward serum but decomposed under ROS-conditions, have appropriate sizes (180~300 nm) and positive zeta-potentials (+35~50 mV). In vitro experiments reveal that these materials have low cytotoxicity, and higher transfection efficiency (TE) than controls. Furthermore, the title polymers exhibit excellent serum tolerance. With the present of 10% serum, the TE of the polymers even increases up to 10 times higher than 25 KDa PEI and 9 times higher than Lipofectamine 2000. The SAR studies also reveal that electron-withdrawing groups on the aromatic ring in 4a may benefit to balance between the DNA condensation and release for efficient gene transfection.

Polyethylenimine-based nanocarriers in co-delivery of drug and gene: a developing horizon

The meaning of gene therapy is the delivery of DNA or RNA to cells for the treatment or prevention of genetic disorders. The success rate of gene therapy depends on the progression and safe gene delivery system. The vectors available for gene therapy are divided into viral and non-viral systems. Viral vectors cause higher transmission efficiency and long gene expression, but they have major problems, such as immunogenicity, carcinogenicity, the inability to transfer large size genes and high costs. Non-viral gene transfer vectors have attracted more attention because they exhibit less toxicity and the ability to transfer large size genes. However, the clinical application of non-viral methods still faces some limitations, including low transmission efficiency and poor gene expression. In recent years, numerous methods and gene-carriers have been developed to improve gene transfer efficiency. The use of Polyethylenimine (PEI) based transfer of collaboration may create a new way of treating diseases and the combination of chemotherapy and gene therapy. The purpose of this paper is to introduce the PEI as an appropriate vector for the effective gene delivery.

Reduction-sensitive polymeric nanomedicines: An emerging multifunctional platform for targeted cancer therapy

The development of smart delivery systems that are robust in circulation and quickly release drugs following selective internalization into target cancer cells is a key to precision cancer therapy. Interestingly, reduction-sensitive polymeric nanomedicines showing high plasma stability and triggered cytoplasmic drug release behavior have recently emerged as one of the most exciting platforms for targeted delivery of various anticancer drugs including small chemical drugs, proteins, and nucleic acids. In vivo studies in varying tumor models reveal that these reduction-sensitive multifunctional nanomedicines outperform the currently used clinical formulations and reduction-insensitive counterparts, bringing about not only significantly enhanced tumor selectivity, accumulation and inhibition efficacy but also markedly reduced systemic toxicity and improved therapeutic index. In this review, we will highlight the cutting-edge advancement with a focus on in vivo performances as well as future perspectives on reduction-sensitive polymeric nanomedicines for targeted cancer therapy.

TAB3 upregulates Survivin expression to promote colorectal cancer invasion and metastasis by binding to the TAK1-TRAF6 complex

Transforming growth factor-β-activated kinase 1 (TAK1)-binding protein 3 (TAB3) is involved in cancer proliferation and metastasis, but its role in colorectal cancer remains unclear. In this study, we demonstrated that TAB3 is upregulated in colorectal cancer tissues and that high TAB3 levels correlated with tumor metastasis and a poor prognosis in colorectal cancer. In addition, TAB3 knockdown decreased Survivin expression and suppressed colorectal cancer cell migration and invasion in vitro, and reduced liver metastasis in vivo. Importantly, we found that TAB3 regulated Survivin expression by activating the NF-κB pathway through the formation of the TAK1-TAB3-TRAF6 complex. These findings suggest TAB3 may be a useful prognostic biomarker in colorectal cancer and a target for treatment of metastatic colorectal cancer.

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.

Intranasal drug delivery of small interfering RNA targeting Beclin1 encapsulated with polyethylenimine (PEI) in mouse brain to achieve HIV attenuation

We previously reported that activation of the host autophagic protein, Beclin1, by HIV-1 infection represents an essential mechanism in controlling HIV replication and viral-induced inflammatory responses in microglial cells. Existing antiretroviral therapeutic approaches have been limited in their ability to cross the blood-brain barrier effectively and recognize and selectively eliminate persistent HIV-infected brain reservoirs. In the present study and for the first time, the bio-distribution and efficacy of noninvasive intranasal delivery of small interfering RNA (siRNA) against the Beclin1 gene using the cationic linear polyethylenimines (PEI) as a gene carrier was investigated in adult mouse brain. Fluorescein isothiocyanate (FITC)-labeled control siRNA delivered intranasally was found in the cytoplasm of neurons and glial cells of the prefrontal cortex at 4 and 24 hours post-delivery, with no major adverse immune reaction encountered. Intranasal delivery of the siRNA targeting Beclin1 significantly depleted the target protein expression levels in brain tissues with no evidence of toxicity. Binding of siRNA to PEI-polymer was characterized and confirmed by Raman spectroscopy. These results indicate that the intranasal drug delivery allows for the direct delivery of the PEI-siRNA nano-complex to the central nervous system, which could potentially offer an efficient means of gene silencing-mediated therapy in the HIV-infected brain.

siRNA-loaded poly(histidine-arginine)6-modified chitosan nanoparticle with enhanced cell-penetrating and endosomal escape capacities for suppressing breast tumor metastasis

An ideal carrier that delivers small interfering RNA (siRNA) should be designed based on two criteria: cellular-mediated internalization and endosomal escape. Poly(histidine-arginine)₆(H6R6) peptide was introduced into chitosan (CS) to create a new CS derivative for siRNA delivery, 6-polyarginine (R6) as cell-penetrating peptides facilitated nanoparticle cellular internalization has been proved in our previous research, and 6-polyhistidine (H6) mediated the nanoparticle endosome escape resulted in the siRNA rapid releasing into tumor cytoplasm. H6R6-modified CS nanoparticles showed higher transfection efficiency and better endosomal escape capacity compared to ungroomed CS nanoparticle in vitro. Noticeably, H6R6-modified CS nanoparticles effectively inhibited tumor cell growth and metastases in vivo and significantly improved survival ratio. Therefore, we concluded that H6R6-modified CS copolymer can act as an ideal carrier for siRNA delivery and as a promising candidate in breast cancer therapy.

Redox-sensitive Pluronic F127-tocopherol micelles: synthesis, characterization, and cytotoxicity evaluation

Pluronic F127 (F127), an amphiphilic triblock copolymer, has been shown to have significant potential for drug delivery, as it is able to incorporate hydrophobic drugs and self-assemble into nanosize micelles. However, it suffers from dissociation upon dilution owing to the relatively high critical micelle concentration and lack of stimuli-responsive behavior. Here, we synthesized the α-tocopherol (TOC) modified F127 polymer (F127-SS-TOC) via a redox-sensitive disulfide bond between F127 and TOC, which formed stable micelles at relatively low critical micelle concentration and was sensitive to the intracellular redox environment. The particle size and zeta potential of the F127-SS-TOC micelles were 51.87±6.39 nm and -8.43±2.27 mV, respectively, and little changes in both particle size and zeta potential were observed within 7 days at room temperature. With 10 mM dithiothreitol stimulation, the F127-SS-TOC micelles rapidly dissociated followed by a significant change in size, which demonstrated a high reduction sensitivity of the micelles. In addition, the micelles showed a high hemocompatibility even at a high micelle concentration (1,000 μg/mL). Low cytotoxicity of the F127-SS-TOC micelles at concentrations ranging from 12.5 μg/mL to 200 μg/mL was also found on both Bel 7402 and L02 cells. Overall, our results demonstrated F127-SS-TOC micelles as a stable and safe aqueous formulation with a considerable potential for drug delivery.

Targeting specificity protein 1 transcription factor and survivin using tolfenamic acid for inhibiting Ewing sarcoma cell growth

Transcription factor Specificity protein 1 (Sp1) and its downstream target survivin (inhibitor of apoptosis protein), play major roles in the pathogenesis of various cancers. Ewing Sarcoma (ES) is a common soft tissue/bone tumor in adolescent and young adults. Overexpression of survivin is also linked to the aggressiveness and poor prognosis of ES. Small molecule Tolfenamic acid (TA) inhibits Sp1 and survivin in cancer cells. In this investigation, we demonstrate a strategy to target Sp1 and survivin using TA and positive control Mithramycin A (Mit) to inhibit ES cell growth. Knock down of Sp1 using small interfering RNA (siRNA) resulted in significant (p < 0.05) inhibition of CHLA-9 and TC-32 cell growth as assessed by CellTiter-Glo assay kit. TA or Mit treatment caused dose/time-dependent inhibition of cell viability, and this inhibition was correlated with a decrease in Sp1 and survivin protein levels in ES cells. Quantitative PCR results showed that Mit treatment decreased the mRNA expression of both survivin and Sp1, whereas TA diminished only survivin but not Sp1. Proteasome inhibitor restored TA-induced inhibition of Sp1 protein expression suggesting that TA might cause proteasome-dependent degradation. Gel shift assay using ES cell nuclear extract and biotinylated Sp1 consensus oligonucleotides confirmed that both TA and Mit decreased DNA-binding activity of Sp1. These results demonstrate that both Mit and TA reduce expression of Sp1 and survivin, disrupt Sp1 DNA-binding and inhibit ES cell proliferation. This investigation suggests that targeting Sp1 and survivin could be an effective strategy for inhibiting ES cell growth.

Biodegradable Poly(Amino Ester) with Aromatic Backbone as Efficient Nonviral Gene Delivery Vectors

The development of gene delivery vectors with high efficiency and biocompatibility is one of the critical points of gene therapy. Two biodegradable poly(amino ester)s were synthesized via ring-opening polymerization between low molecular weight (LMW) PEI and diepoxide. The molecular weights of poly(amino ester)s were measured by GPC. Agarose gel retardation assays showed that these materials have good DNA-binding ability and can retard the electrophoretic mobility of plasmid DNA (pDNA) at a weight ratio of 1. The formed polyplexes have proper sizes of around 200 nm and zeta-potential values of about 30-40 mV for cellular uptake. In vitro experiments revealed that polymer P2 gave higher transfection efficiency than PEI 25KDa and Lipofectamine 2000 with less toxicity, especially in 293 cells. Results demonstrate that such a type of degradable poly(amino ester) may serve as a promising non-viral gene vector.

Gene-silencing effects of anti-survivin siRNA delivered by RGDV-functionalized nanodiamond carrier in the breast carcinoma cell line MCF-7

Nanodiamond (ND) is a renowned material in nonviral small interfering RNA (siRNA) carrier field due to its unique physical, chemical, and biological properties. In our previous work, it was proven that ND could deliver siRNA into cells efficiently and downregulate the expression of desired protein. However, synthesizing a high-efficient tumor-targeting carrier using ND is still a challenge. In this study, a novel carrier, NDCONH(CH₂)₂NH-VDGR, was synthesized for siRNA delivery, and its properties were characterized with methods including Fourier transform infrared spectrometry, transmission electron microscopy, scanning electron microscopy, gel retardation assay, differential scanning calorimetry, confocal microscopy, releasing test, real-time polymerase chain reaction (PCR) assay, enzyme-linked immunosorbent assay (ELISA), flow cytometry, cytotoxicity assay, and gene-silencing efficacy assay in vitro and in vivo. The mechanism of NDCONH(CH₂)₂NH-VDGR/survivin-siRNA-induced tumor apoptosis was evaluated via flow cytometer assay using Annexin V–fluorescein isothiocyanate/propidium iodide staining method. The NDCONH(CH₂)₂NH-VDGR/survivin-siRNA nanoparticle with 60–110 nm diameter and 35.65±3.90 mV zeta potential was prepared. For real-time PCR assay, the results showed that the expression of survivin mRNA was reduced to 46.77%±6.3%. The expression of survivin protein was downregulated to 48.49%±2.25%, as evaluated by ELISA assay. MTT assay showed that NDCONH(CH₂)₂NH-VDGR/survivin-siRNA had an inhibitory effect on MCF-7 cell proliferation. According to these results, the survivin-siRNA could be delivered, transported, and released stably, which benefits in increasing the gene-silencing effect. Therefore, as an siRNA carrier, NDCONH(CH₂)₂NH-VDGR was suggested to be used in siRNA delivery system and in cancer treatments.

An effective tumor-targeting strategy utilizing hypoxia-sensitive siRNA delivery system for improved anti-tumor outcome

Hypoxia is a feature of most solid tumors, targeting hypoxia is considered as the best validated yet not extensively exploited strategy in cancer therapy. Here, we reported a novel tumor-targeting strategy using a hypoxia-sensitive siRNA delivery system. In the study, 2-nitroimidazole (NI), a hydrophobic component that can be converted to hydrophilic 2-aminoimidazole (AI) through bioreduction under hypoxic conditions, was conjugated to the alkylated polyethyleneimine (bPEI1.8k-C6) to form amphiphilic bPEI1.8k-C6-NI polycations. bPEI1.8k-C6-NI could self-assemble into micelle-like aggregations in aqueous, which contributed to the improved stability of the bPEI1.8k-C6-NI/siRNA polyplexes, resulted in increased cellular uptake. After being transported into the hypoxic tumor cells, the selective nitro-to-amino reduction would cause structural change and elicit a relatively loose structure to facilitate the siRNA dissociation in the cytoplasm, for enhanced gene silencing efficiency ultimately. Therefore, the conflict between the extracellular stability and the intracellular siRNA release ability of the polyplexes was solved by introducing the hypoxia-responsive unit. Consequently, the survivin-targeted siRNA loaded polyplexes shown remarkable anti-tumor effect not only in hypoxic cells, but also in tumor spheroids and tumor-bearing mice, indicating that the hypoxia-sensitive siRNA delivery system had great potential for tumor-targeted therapy.

STATEMENT OF SIGNIFICANCE

Hypoxia is one of the most remarkable features of most solid tumors, and targeting hypoxia is considered as the best validated strategy in cancer therapy. However, in the past decades, there were few reports about using this strategy in the drug delivery system, especially in siRNA delivery system. Therefore, we constructed a hypoxia-sensitive siRNA delivery system utilizing a hypoxia-responsive unit, 2-nitroimidazole, by which the unavoidable conflict between improved extracellular stability and promoted intracellular siRNA release in the same delivery system could be effectively solved, resulting in enhanced siRNA silencing efficiency in tumor cells. To our knowledge, the described work is the first demonstration of a siRNA delivery system using a hypoxia trigger for regulation of siRNA release, which represents a new strategy for tumor-targeted therapy, and it is expected that this meaningful strategy must be widely applied in the future.

Chitosan-based nanoparticles for survivin targeted siRNA delivery in breast tumor therapy and preventing its metastasis

Nanoparticle-mediated small interfering RNA (siRNA) delivery is a promising therapeutic strategy in various cancers. However, it is difficult to deliver degradative siRNA to tumor tissue, and thus a safe and efficient vector for siRNA delivery is essential for cancer therapy. In this study, poly(ethylene glycol)-modified chitosan (PEG-CS) was synthesized successfully for delivering nucleic acid drug. We deemed that PEGylated CS could improve its solubility by forming a stable siRNA loaded in nanoparticles, and enhancing transfection efficiency of siRNA-loaded CS nanoparticles in cancer cell line. The research results showed that siRNA loaded in PEGylated CS (PEG-CS/siRNA) nanoparticles with smaller particle size had superior structural stability in the physical environment compared to CS nanoparticles. The data of in vitro antitumor activity revealed that 4T1 tumor cell growth was significantly inhibited and cellular uptake of PEG-CS/siRNA nanoparticles in 4T1 cells was dramatically enhanced compared to naked siRNA groups. The results from flow cytometry and confocal laser scanning microscopy showed that PEG-CS/siRNA nanoparticles were more easily taken up than naked siRNA. Importantly, PEG-CS/siRNA nanoparticles significantly reduced the growth of xenograft tumors of 4T1 cells in vivo. It has been demonstrated that the PEG-CS is a safe and efficient vector for siRNA delivery, and it can effectively reduce tumor growth and prevent metastasis.

Evaluation of survivin expression in prostate specimens of patients with prostate adenocarcinoma and benign prostate hyperplasia underwent transurethral resection of the prostate or prostatectomy

BACKGROUND

Survivin is a newly found member of the inhibitors of apoptosis proteins, which plays a certain role in cancer. Survivin has a distinctly different expression in cancers, including prostate cancer. We are searching for the relationship between survivin levels in normal prostate tissue, benign prostate hyperplasia (BPH), and prostate adenocarcinoma in this study.

RESULTS

The study surveyed 282 prostate samples, 94 normal, 94 BPH, and 94 prostate adenocarcinoma samples. Survivin expression was absent in normal prostate tissues. In the BPH group, the survivin expression level was higher than that of the normal group. In the adenocarcinoma group, the survivin expression level was higher than that of the BPH group. There was a significant association between survivin expression level and the adenocarcinoma stage.

CONCLUSION

Although there is no expression of survivin in normal prostate tissue, its expression is slightly positive in BPH. High survivin expression is related to a higher Gleason score in the adenocarcinoma of the prostate.