Pulmonary Codelivery of Doxorubicin and siRNA by pH‐Sensitive Nanoparticles for Therapy of Metastatic Lung Cancer

A pulmonary codelivery system that can simultaneously deliver doxorubicin (DOX) and Bcl2 siRNA to the lungs provides a promising local treatment strategy for lung cancers. In this study, DOX is conjugated onto polyethylenimine (PEI) by using cis‐aconitic anhydride (CA, a pH‐sensitive linker) to obtain PEI‐CA‐DOX conjugates. The PEI‐CA‐DOX/siRNA complex nanoparticles are formed spontaneously via electrostatic interaction between cationic PEI‐CA‐DOX and anionic siRNA. The drug release experiment shows that DOX releases faster at acidic pH than at pH 7.4. Moreover, PEI‐CA‐DOX/Bcl2 siRNA complex nanoparticles show higher cytotoxicity and apoptosis induction in B16F10 cells than those treated with either DOX or Bcl2 siRNA alone. When the codelivery systems are directly sprayed into the lungs of B16F10 melanoma‐bearing mice, the PEI‐CA‐DOX/Bcl2 siRNA complex nanoparticles exhibit enhanced antitumor efficacy compared with the single delivery of DOX or Bcl2 siRNA. Compared with systemic delivery, most drug and siRNA show a long‐term retention in the lungs via pulmonary delivery, and a considerable number of the drug and siRNA accumulate in tumor tissues of lungs, but rarely in normal lung tissues. The PEI‐CA‐DOX/Bcl2 siRNA complex nanoparticles are promising for the treatment of metastatic lung cancer by pulmonary delivery with low side effects on the normal tissues.     

A novel cationic liposome formulation for efficient gene delivery via a pulmonary route

The clinical success of gene therapy for lung cancer is not only dependent on efficient gene carriers but also on a suitable delivery route. A pulmonary delivery route can directly deliver gene vectors to the lung which is more efficient than a systemic delivery route. For gene carriers, cationic liposomes have recently emerged as leading non-viral vectors in worldwide gene therapy clinical trials. However, cytotoxic effects or apoptosis are often observed which is mostly dependent on the cationic lipid used. Therefore, an efficient and safe cationic lipid, 6-lauroxyhexyl lysinate (LHLN), previously synthesized by our group was first used to prepare cationic liposomes. Physicochemical and biological properties of LHLN-liposomes were investigated. LHLN-liposome/DNA complexes showed positive surface charge, spherical morphology, a relatively narrow particle size distribution and strong DNA binding capability. Compared with Lipofectamine2000, the new cationic liposome formulation using LHLN exhibited not only lower cytotoxicity (P < 0.05) but also similar transfection efficiency in A549 and HepG2 lung cancer cells for in vitro tests. When administered by intratracheal instillation into rat lungs for in vivo evaluation, LHLN-liposome/DNA complexes exhibited higher pulmonary gene transfection efficiency than Lipofectamine2000/DNA complexes (P < 0.05). These results suggested that LHLN-liposomes may have great potential for efficient pulmonary gene delivery.     

Gold Nanoparticles Capped with Polyethyleneimine for Enhanced siRNA Delivery

An efficient and safe delivery system for small interfering RNA (siRNA) is required for clinical application of RNA interfering therapeutics. Polyethyleneimine (PEI)‐capped gold nanoparticles (AuNPs) are successfully manufactured using PEI as the reductant and stabilizer, which bind siRNA at an appropriate weight ratio by electrostatic interaction and result in well‐dispersed nanoparticles with uniform structure and narrow size distribution. With siRNA binding, PEI‐capped AuNPs induce more significant and enhanced reduction in targeted green fluorescent protein expression in MDA‐MB‐435s cells, though more internalized PEI/siRNA complexes in cells are evidenced by confocal laser scanning microscopy observation and fluorescence‐activated cell sorting analyses. PEI‐capped AuNPs/siRNA targeting endogenous cell‐cycle kinase, an oncogene polo‐like kinase 1 (PLK1), display significant gene expression knockdown and induce enhanced cell apoptosis, whereas it is not obvious when the cells are treated with PLK1 siRNA using PEI as the carrier. Without exhibiting cellular toxicity, PEI‐capped AuNPs appear to be suitable as a potential carrier for intracellular siRNA delivery.     

Biodegradable Nanocapsules as siRNA Carriers for Mutant K‐Ras Gene Silencing of Human Pancreatic Carcinoma Cells

The application of small interfering RNA (siRNA)‐based RNA interference (RNAi) for cancer gene therapy has attracted great attention. Gene therapy is a promising strategy for cancer treatment because it is relatively non‐invasive and has a higher therapeutic specificity than chemotherapy. However, without the use of safe and efficient carriers, siRNAs cannot effectively penetrate the cell membranes and RNAi is impeded. In this work, cationic poly(lactic acid) (CPLA)‐based degradable nanocapsules (NCs) are utilized as novel carriers of siRNA for effective gene silencing of pancreatic cancer cells. These CPLA‐NCs can readily form nanoplexes with K‐Ras siRNA and over 90% transfection efficiency is achieved using the nanoplexes. Cell viability studies show that the nanoparticles are highly biocompatible and non‐toxic, indicating that CPLA‐NC is a promising potential candidate for gene therapy in a clinical setting.     

A Poly(Propyleneimine) Dendrimer‐Based Polyplex‐System for Single‐Chain Antibody‐Mediated Targeted Delivery and Cellular Uptake of SiRNA

Therapeutics based on small interfering RNAs (siRNAs) offer a great potential to treat so far incurable diseases or metastatic cancer. However, the broad application of siRNAs using various nonviral carrier systems is hampered by unspecific toxic side effects, poor pharmacokinetics due to unwanted delivery of siRNA‐loaded nanoparticles into nontarget organs, or rapid renal excretion. In order to overcome these obstacles, several targeting strategies using chemically linked antibodies and ligands have emerged. This study reports a new modular polyplex carrier system for targeted delivery of siRNA, which is based on transfection‐disabled maltose‐modified poly(propyleneimine)‐dendrimers (mal‐PPI) bioconjugated to single chain fragment variables (scFvs). To achieve targeted delivery into tumor cells expressing the epidermal growth factor receptor variant III (EGFRvIII), monobiotinylated anti‐EGFRvIII scFv fused to a Propionibacterium shermanii transcarboxylase‐derived biotinylation acceptor (P‐BAP) is bioconjugated to mal‐PPI through a novel coupling strategy solely based on biotin–neutravidin bridging. In contrast to polyplexes containing an unspecific control scFv‐P‐BAP, the generated EGFRvIII‐specific polyplexes are able to exclusively deliver siRNA to tumor cells and tumors by receptor‐mediated endocytosis. These results suggest that receptor‐mediated uptake of otherwise noninternalized mal‐PPI‐based polyplexes is a promising avenue to improve siRNA therapy of cancer, and introduce a novel strategy for modular bioconjugation of protein ligands to nanoparticles.     

Highly efficient gene silencing and bioimaging based on fluorescent carbon dots <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>

Small interfering RNA (siRNA) is an attractive therapeutic candidate for sequencespecific gene silencing to treat incurable diseases using small molecule drugs.However,its efficient intracellular delivery has remained a challenge.Here,we have developed a highly biocompatible fluorescent carbon dot (CD),and demonstrate a functional siRNA delivery system that induces efficient gene knockdown in vitro and in vivo.We found that CD nanoparticles (NPs) enhance the cellular uptake of siRNA,via endocytosis in tumor cells,with low cytotoxicity and unexpected immune responses.Real-time study of fluorescence imaging in live cells shows that CD NPs favorably localize in cytoplasm and successfully release siRNA within 12 h.Moreover,we demonstrate that CD NP-mediated siRNA delivery significantly silences green fluorescence protein (GFP) expression and inhibits tumor growth in a breast cancer cell xenograft mouse model of tumor-specific therapy.We have developed a multi functional siRNA delivery vehicle enabling simultaneous bioimaging and efficient downregulation of gene expression,that shows excellent potential for gene therapy.     

A Highly Entangled Polymeric Nanoconstruct Assembled by siRNA and its Reduction‐Triggered siRNA Release for Gene Silencing

A nanoconstruct (NC) is developed from a biocompatible natural polymer and siRNA conjugates to deliver small interfering RNA (siRNA) target‐specifically without cationic condensation reagents. This study reports a novel siRNA‐mediated cross‐linked NC produced by hybridizing two complementary single‐stranded siRNAs that are conjugated to the polymer dextran via a disulfide linkage. The reducible disulfide bond between the siRNA and polymer allow siRNA release from the NC in the reducible cytoplasmic region after the NC enters the cell. In addition, when the NC contains the prostate‐carcinoma‐binding peptide aptamer DUP‐1, it can selectively deliver siRNA into prostate cancer cells of the PC‐3 lines; thus, the newly formulated NC has reduced the cytotoxicity and improved the efficacy of target‐specific siRNA delivery. Moreover, this new concept of NCs using biocompatible siRNA and a neutral polymer may provide insightful knowledge for future directions for designing NCs for stimuli‐responsive and advanced target‐specific siRNA delivery.     

In Vivo Environment‐Adaptive Nanocomplex with Tumor Cell–Specific Cytotoxicity Enhances T Cells Infiltration and Improves Cancer Therapy

Drug delivery strategies possessing selectivity for cancer cells are eagerly needed in therapy of metastatic breast cancer. In this study, the chemotherapeutic agent, docetaxel (DTX), is conjugated onto heparan sulfate (HS). Aspirin (ASP), which has the activity of anti‐metastasis and enhancing T cells infiltration in tumors, is encapsulated into the HS‐DTX micelle. Then the cationic polyethyleneimine (PEI)‐polyethylene glycol (PEG) copolymer binds to HS via electrostatic force, forming the ASP‐loaded HS‐DTX micelle (AHD)/PEI‐PEG nanocomplex (PAHD). PAHD displays long circulation behavior in blood due to the PEG shell. Under the tumor microenvironment with weakly acidic pH, PEI‐PEG separates from AHD, and the free cationic PEI‐PEG facilitates the cellular uptake of AHD by increasing permeability of cell membranes. Then the overexpressed heparanase degrades HS, releasing ASP and DTX. PAHD shows specific toxicity toward tumor cells but not normal cells, with advanced activity of inhibiting tumor growth and lung metastasis in 4T1 tumor‐bearing mice. The number of CD8⁺ T cells in tumor tissues is also increased. Therefore, PAHD can become an efficient drug delivery system for breast cancer treatment.     

Spray‐Dried Nanoparticle‐in‐Microparticle Delivery Systems (NiMDS) for Gene Delivery,Comprising Polyethylenimine (PEI)‐Based Nanoparticles in a Poly(Vinyl Alcohol) Matrix

Nucleic acid‐based therapies rely on efficient formulations for nucleic acid protection and delivery. As nonviral strategies, polymeric and lipid‐based nanoparticles have been introduced; however, biological efficacy and biocompatibility as well as poor storage properties due to colloidal instability and their unavailability as ready‐to‐use systems are still major issues. Polyethylenimine is the most widely explored and promising candidate for gene delivery. Polyethylenimine‐based polyplexes and their combination with liposomes, lipopolyplexes, are efficient for DNA or siRNA delivery in vitro and in vivo. In this study, a highly potent spray‐dried nanoparticle‐in‐microparticle delivery system is presented for the encapsulation of polyethylenimine‐based polyplexes and lipopolyplexes into poly(vinyl alcohol) microparticles, without requiring additional stabilizing agents. This easy‐to‐handle gene delivery device allows prolonged nanoparticle storage and protection at ambient temperature. Biological analyses reveal further advantages regarding profoundly reduced cytotoxicity and enhanced transfection efficacies of polyethylenimine‐based nanoparticles from the nanoparticle‐in‐microparticle delivery system over their freshly prepared counterparts, as determined in various cell lines. Importantly, this nanoparticle‐in‐microparticle delivery system is demonstrated as ready‐to‐use dry powder to be an efficient device for the inhalative delivery of polyethylenimine‐based lipopolyplexes in vivo, as shown by transgene expression in mice after only one administration.     

Targeted Delivery of siRNA‐Generating DNA Nanocassettes Using Multifunctional Nanoparticles

Molecular therapy using a small interfering RNA (siRNA) has shown promise in the development of novel therapeutics. Various formulations have been used for in vivo delivery of siRNAs. However, the stability of short double‐stranded RNA molecules in the blood and efficiency of siRNA delivery into target organs or tissues following systemic administration have been the major issues that limit applications of siRNA in human patients. In this study, multifunctional siRNA delivery nanoparticles are developed that combine imaging capability of nanoparticles with urokinase plasminogen activator receptor‐targeted delivery of siRNA expressing DNA nanocassettes. This theranostic nanoparticle platform consists of a nanoparticle conjugated with targeting ligands and double‐stranded DNA nanocassettes containing a U6 promoter and a shRNA gene for in vivo siRNA expression. Targeted delivery and gene silencing efficiency of firefly luciferase siRNA nanogenerators are demonstrated in tumor cells and in animal tumor models. Delivery of survivin siRNA expressing nanocassettes into tumor cells induces apoptotic cell death and sensitizes cells to chemotherapy drugs. The ability of expression of siRNAs from multiple nanocassettes conjugated to a single nanoparticle following receptor‐mediated internalization should enhance the therapeutic effect of the siRNA‐mediated cancer therapy.     

Co-delivery of drugs and DNA from cationic core-shell nanoparticles self-assembled from a biodegradable copolymer

Non-viral gene-delivery systems are safer to use and easier to produce than viral vectors, but their comparatively low transfection efficiency has limited their applications. Co-delivery of drugs and DNA has been proposed to enhance gene expression or to achieve the synergistic/combined effect of drug and gene therapies. Attempts have been made to deliver drugs and DNA simultaneously using liposomes. Here we report cationic core-shell nanoparticles that were self-assembled from a biodegradable amphiphilic copolymer. These nanoparticles offer advantages over liposomes, as they are easier to fabricate, and are more readily subject to modulation of their size and degree of positive charge. More importantly, they achieve high gene-transfection efficiency and the possibility of co-delivering drugs and genes to the same cells. Enhanced gene transfection with the co-delivery of paclitaxel has been demonstrated by in vitro and in vivo studies. In particular, the co-delivery of paclitaxel with an interleukin-12-encoded plasmid using these nanoparticles suppressed cancer growth more efficiently than the delivery of either paclitaxel or the plasmid in a 4T1 mouse breast cancer model. Moreover, the co-delivery of paclitaxel with Bcl-2-targeted small interfering RNA (siRNA) increased cytotoxicity in MDA-MB-231 human breast cancer cells.     

Virus‐Mimicking Chimaeric Polymersomes Boost Targeted Cancer siRNA Therapy In Vivo

Small interfering RNA (siRNA) offers a highly selective and effective pharmaceutical for various life‐threatening diseases, including cancers. The clinical translation of siRNA is, however, challenged by its short plasma life, poor cell uptake, and cumbersome intracellular trafficking. Here, cNGQGEQc peptide‐functionalized reversibly crosslinked chimaeric polymersomes (cNGQ/RCCPs) is shown to mediate high‐efficiency targeted delivery of Polo‐like kinase1 specific siRNA (siPLK1) to orthotopic human lung cancer in nude mice. Strikingly, siRNA is completely and tightly loaded into the aqueous lumen of the polymersomes at an unprecedentedly low N/P ratio of 0.45. cNGQ/RCCPs loaded with firefly luciferase specific siRNA (siGL3) or siPLK1 are efficiently taken up by α₃β₁‐integrin‐overexpressing A549 lung cancer cells and quickly release the payloads to the cytoplasm, inducing highly potent and sequence‐specific gene silencing in vitro. The in vivo studies using nude mice bearing orthotopic A549 human lung tumors reveal that siPLK1‐loaded cNGQ/RCCPs boost long circulation, superb tumor accumulation and selectivity, effective suppression of tumor growth, and significantly improved survival time. These virus‐mimicking chimaeric polymersomes provide a robust and potent platform for targeted cancer siRNA therapy.     

Antibody Conjugated PLGA Nanoparticles for Targeted Delivery of Paclitaxel Palmitate: Efficacy and Biofate in a Lung Cancer Mouse Model

Aberrant signaling of the epidermal growth factor receptor (EGFR) is common to a variety of human cancers and is also found to be over‐expressed in most cases of non‐small cell lung cancer. For the development of a molecularly targeted therapy, cetuximab‐conjugated nanoparticles (immunonanoparticles, INPs) are designed and loaded with the lipophilic paclitaxel palmitate (pcpl) prodrug. Oleyl cysteineamide (OCA) is synthesized whereby its amphiphilic nature enables interfacial anchoring and thiol surface functionalization of PLGA NPs, facilitating bioconjugation to cetuximab by thioether bonds. It is demonstrated that the in vitro targeting efficiency and improved cellular internalization and cytotoxicity of this targeted delivery system in lung cancer cells over‐expressing EGFR. A quantitative measure of the high binding affinity of INPs to EGFR is demonstrated using surface plasmon resonance. In vivo tolerability and enhanced efficacy of cetuximab pcpl INPs in a metastatic lung cancer model are reported. Its therapeutic efficacy in A549‐luc‐C8 lung tumors is shown using non‐invasive bioluminescent imaging. Intravenous administration of cetuximab pcpl INPs to mice results in significantly higher inhibition of tumor growth and increased survival rates as compared to the non‐targeted drug solution, drug‐loaded nanoparticles or blank INPs. Pharmacokinetics and organ biodistribution of the prodrug and parent drug are evaluated by LC‐MS/MS in lung tumor bearing mice. No enhanced total accumulation of nanoparticles or INPs is found at the tumor tissue. However, persistent pcpl levels with sustained conversion and release of paclitaxel are observed for the encapsulated prodrug possibly suggesting the formation of a drug reservoir. The overall results indicate the potential of this promising targeted platform for the improved treatment of lung cancer and other EGFR positive tumors.     

Inhibition of Tumor‐Cell Invasion with Chlorotoxin‐Bound Superparamagnetic Nanoparticles

Nanoparticles have been investigated as drug delivery vehicles, contrast agents, and multifunctional devices for patient care. Current nanoparticle‐based therapeutic strategies for cancer treatment are mainly based on delivery of chemotherapeutic agents to induce apoptosis or DNA/siRNA to regulate oncogene expression. Here, a nanoparticle system that demonstrates an alternative approach to the treatment of cancers through the inhibition of cell invasion, while serving as a magnetic resonance and optical imaging contrast agent, is presented. The nanoparticle comprises an iron oxide nanoparticle core conjugated with an amine‐functionalized poly(ethylene glycol) silane and a small peptide, chlorotoxin (CTX), which enables the tumor cell‐specific binding of the nanoparticle. It is shown that the nanoparticle exhibits substantially enhanced cellular uptake and an invasion inhibition rate of ～98% compared to unbound CTX (～45%). Significantly, the investigation from flow cytometry analysis, transmission electron microscopy, and fluorescent imaging reveals that the CTX‐enabled nanoparticles deactivated the membrane‐bound matrix metalloproteinase 2 (MMP‐2) and induced increased internalization of lipid rafts that contain surface‐expressed MMP‐2 and volume‐regulating ion channels through receptor‐mediated endocytosis, leading to enhanced prohibitory effects. Since upregulation and activity of MMP‐2 have been observed in tumors of neuroectodermal origin, and in cancers of the breast, colon, skin, lung, prostate, ovaries, and a host of others, this nanoparticle system can be potentially used for non‐invasive diagnosis and treatment of a variety of cancer types.     

N-Alkyl-PEI-functionalized iron oxide nanoclusters for efficient siRNA delivery

Small-interfering RNA (siRNA) is an emerging class of therapeutics, which works by regulating the expression of a specific gene involved in disease progression. Despite the promises, effective transport of siRNA with minimal side effects remains a challenge. In this study, a nonviral nanoparticle gene carrier is developed and its efficiency for siRNA delivery and transfection is validated at both in vitro and in vivo levels. Such a nanocarrier, abbreviated as Alkyl-PEI2k-IO, was constructed with a core of iron oxide nanoparticles (IOs) and a shell of alkylated polyethyleneimine of 2000 Da [corrected] molecualr weight (Alkyl-PEI2k). It is found to be able to bind with siRNA, resulting in well-dispersed nanoparticles with a controlled clustering structure and narrow size distribution. Electrophoresis studies show that the Alkyl-PEI2k-IOs could retard siRNA completely at N:P ratios (i.e., PEI nitrogen to nucleic acid phosphate) above 10, protect siRNA from enzymatic degradation in serum, and release complexed siRNA efficiently in the presence of polyanionic heparin. The knockdown efficiency of the siRNA-loaded nanocarriers is assessed with 4T1 cells stably expressing luciferase (fluc-4T1) and further, with a fluc-4T1 xenograft model. Significant down-regulation of luciferase is observed, and unlike high-molecular-weight analogues, the Alkyl-PEI2k-coated IOs show good biocompatibility. In conclusion, Alkyl-PEI2k-IOs demonstrate highly efficient delivery of siRNA and an innocuous toxic profile, making it a potential carrier for gene therapy.     

Immune Cell‐Mediated Biodegradable Theranostic Nanoparticles for Melanoma Targeting and Drug Delivery

Although tremendous efforts have been made on targeted drug delivery systems, current therapy outcomes still suffer from low circulating time and limited targeting efficiency. The integration of cell‐mediated drug delivery and theranostic nanomedicine can potentially improve cancer management in both therapeutic and diagnostic applications. By taking advantage of innate immune cell's ability to target tumor cells, the authors develop a novel drug delivery system by using macrophages as both nanoparticle (NP) carriers and navigators to achieve cancer‐specific drug delivery. Theranostic NPs are fabricated from a unique polymer, biodegradable photoluminescent poly (lactic acid) (BPLP‐PLA), which possesses strong fluorescence, biodegradability, and cytocompatibility. In order to minimize the toxicity of cancer drugs to immune cells and other healthy cells, an anti‐BRAF V600E mutant melanoma specific drug (PLX4032) is loaded into BPLP‐PLA nanoparticles. Muramyl tripeptide is also conjugated onto the nanoparticles to improve the nanoparticle loading efficiency. The resulting nanoparticles are internalized within macrophages, which are tracked via the intrinsic fluorescence of BPLP‐PLA. Macrophages carrying nanoparticles deliver drugs to melanoma cells via cell–cell binding. Pharmacological studies also indicate that the PLX4032 loaded nanoparticles effectively kill melanoma cells. The “self‐powered” immune cell‐mediated drug delivery system demonstrates a potentially significant advancement in targeted theranostic cancer nanotechnologies.     

Nanodiamond as a vector for siRNA delivery to Ewing sarcoma cells

The ability of diamond nanoparticles (nanodiamonds, NDs) to deliver small interfering RNA (siRNA) into Ewing sarcoma cells is investigated with a view to the possibility of in-vivo anticancer nucleic-acid drug delivery. siRNA is adsorbed onto NDs that are coated with cationic polymer. Cell uptake of NDs is demonstrated by taking advantage of the NDs' intrinsic fluorescence from embedded color-center defects. Cell toxicity of these coated NDs is shown to be low. Consistent with the internalization efficacy, a specific inhibition of EWS/Fli-1 gene expression is shown at the mRNA and protein level by the ND-vectorized siRNA in a serum-containing medium.     

Layer‐by‐Layer Nanoparticles as an Efficient siRNA Delivery Vehicle for SPARC Silencing

Efficient and safe delivery systems for siRNA therapeutics remain a challenge. Elevated secreted protein, acidic, and rich in cysteine (SPARC) protein expression is associated with tissue scarring and fibrosis. Here we investigate the feasibility of encapsulating SPARC‐siRNA in the bilayers of layer‐by‐layer (LbL) nanoparticles (NPs) with poly(L‐arginine) (ARG) and dextran (DXS) as polyelectrolytes. Cellular binding and uptake of LbL NPs as well as siRNA delivery were studied in FibroGRO cells. siGLO‐siRNA and SPARC‐siRNA were efficiently coated onto hydroxyapatite nanoparticles. The multilayered NPs were characterized with regard to particle size, zeta potential and surface morphology using dynamic light scattering and transmission electron microscopy. The SPARC‐gene silencing and mRNA levels were analyzed using ChemiDOC western blot technique and RT‐PCR. The multilayer SPARC‐siRNA incorporated nanoparticles are about 200 nm in diameter and are efficiently internalized into FibroGRO cells. Their intracellular fate was also followed by tagging with suitable reporter siRNA as well as with lysotracker dye; confocal microscopy clearly indicates endosomal escape of the particles. Significant (60%) SPARC‐gene knock down was achieved by using 0.4 pmole siRNA/μg of LbL NPs in FibroGRO cells and the relative expression of SPARC mRNA reduced significantly (60%) against untreated cells. The cytotoxicity as evaluated by xCelligence real‐time cell proliferation and MTT cell assay, indicated that the SPARC‐siRNA‐loaded LbL NPs are non‐toxic. In conclusion, the LbL NP system described provides a promising, safe and efficient delivery platform as a non‐viral vector for siRNA delivery that uses biopolymers to enhance the gene knock down efficiency for the development of siRNA therapeutics.     

Protamine and chloroquine enhance gene delivery and expression mediated by RNA-wrapped single walled carbon nanotubes

The use of non-viral vectors as delivery systems in gene therapy has been extensively studied recently owing to their advantages over viral vectors. Here, we propose a new gene delivery system based on the use of RNA-wrapped single-walled carbon nanotubes (SWCNTs) complexed with the cationic protein, protamine and the drug chloroquine. Protamine was selected as a cationic protein acting as bridge between negatively charged RNA-wrapped SWCNTs and plasmid DNA. Protamine also contains a nuclear localization signal which enhances the expression of the transfected gene. The drug chloroquine, a lysosomotropic compound which has been reported to increase the transfection efficiency, was attached to RNA-wrapped SWNTs by ionic interactions. The simultaneous delivery of the drug chloroquine with plasmid DNA clearly showed an enhanced gene delivery and expression. The levels of gene expression were quantified using the luciferase reporter gene as model. Optimal conditions for transfection and gene expression were obtained and cytoxicity of the carbon nanotube complexes measured. The optimal complexes were shown to efficiently deliver plasmid DNA for efficient gene expression and may thereby be useful as gene delivery systems for gene therapy.     

The Architecture and Function of Monoclonal Antibody‐Functionalized Mesoporous Silica Nanoparticles Loaded with Mifepristone: Repurposing Abortifacient for Cancer Metastatic Chemoprevention

The circulating tumor cells (CTCs) existing in cancer survivors are considered the root cause of cancer metastasis. To prevent the devastating metastasis cascade from initiation, we hypothesize that a biodegradable nanomaterial loaded with the abortifacient mifepristone (MIF) and conjugated with the epithelial cell adhesion molecule antibody (aEpCAM) may serve as a safe and effective cancer metastatic preventive agent by targeting CTCs and preventing their adhesion‐invasion to vascular intima. It is demonstrated that MIF‐loaded mesoporous silica nanoparticles (MSN) coated with aEpCAM (aE‐MSN‐M) can specifically target and bind colorectal cancer cells in either cell medium or blood through EpCAM recognition proven by quantitative flow cytometric detection and free aEpCAM competitive assay. The specific binding results in downregulation of the captured cells and drives them into G0/G1 phase primarily attributed to the effect of aEpCAM. The functional nanoparticles significantly inhibit the heteroadhesion between cancer cells and endothelial cells, suggesting the combined inhibition effects of aEpCAM and MIF on E‐selectin and ICAM‐1 expression. The functionalized nanoparticles circulate in mouse blood long enough to deliver MIF and inhibit lung metastasis. The present proof‐of‐concept study shows that the aE‐MSN‐M can prevent cancer metastasis by restraining CTC activity and their adhesion‐invasion to vascular intima.