A gene nanocomplex conjugated with monoclonal antibodies for targeted therapy of hepatocellular carcinoma

Polyethyleneimine-Based Drug Delivery Systems for Cancer Theranostics

With the development of nanotechnology, various types of polymer-based drug delivery systems have been designed for biomedical applications. Polymer-based drug delivery systems with desirable biocompatibility can be efficiently delivered to tumor sites with passive or targeted effects and combined with other therapeutic and imaging agents for cancer theranostics. As an effective vehicle for drug and gene delivery, polyethyleneimine (PEI) has been extensively studied due to its rich surface amines and excellent water solubility. In this work, we summarize the surface modifications of PEI to enhance biocompatibility and functionalization. Additionally, the synthesis of PEI-based nanoparticles is discussed. We further review the applications of PEI-based drug delivery systems in cancer treatment, cancer imaging, and cancer theranostics. Finally, we thoroughly consider the outlook and challenges relating to PEI-based drug delivery systems.

Nanocarrier-Based Tumor-Targeting Drug Delivery Systems for Hepatocellular Carcinoma Treatments: Enhanced Therapeutic Efficacy and Reduced Drug Toxicity

Hepatocellular carcinoma (HCC), due to the lack of efficient diagnostic methods and short of available treatments, becomes the third main cause of cancer deaths. Novel treatments for HCCs are thus in great need. The fast-growing area of drug delivery provides intriguing possibility to design nanocarriers with unique properties. The nanocarriers performanced as drug deliver vehicles enable the design of diverse drug delivery systems, which could serve multiple purposes, including improved bioavailability, controlled or triggered release and targeted delivery, leading to enhanced drug efficacy and lowered drug toxicity. This paper provides an overview on the types of delivery vehicles, functions of drug nanocarriers and types of ligand-based targeting systems and highlights the advances made towards better HCC treatments.

Conventional and hybrid nanoparticulate systems for the treatment of hepatocellular carcinoma: An updated review

Hepatocellular carcinoma (HCC) is considered a serious malignancy which affects a large number of people worldwide. Despite the presence of some diagnostic techniques for HCC, the fact that its symptoms somehow overlap with other diseases causes it to be diagnosed at a late stage, hence negatively affecting the prognosis of the disease. The currently available treatment strategies have many shortcomings such as high cost, induction of serious side effects as well as multiple drug resistance, hence resulting in therapeutic failure. Accordingly, nanoformulations have been developed in order to overcome the clinical challenges, enhance the therapeutic efficacy, and elicit chemotherapy tailor-ability. Hybrid nanoparticulate carriers in particular, which are composed of two or more drug vehicles with different physicochemical characteristics combined together in one system, have been recently reported to advance nanotechnology-based therapies. Therefore, this review sheds the light on HCC, and the role of nanotechnology and hybrid nanoparticulate carriers as well as the latest developments in the use of conventional nanoparticles in combating this disease.

Au-siRNA@ aptamer nanocages as a high-efficiency drug and gene delivery system for targeted lung cancer therapy

BACKGROUND

Gene and chemical therapy has become one of the rising stars in the field of molecular medicine during the last two decades. However, there are still numerous challenges in the development of efficient, targeted, and safe delivery systems that can avoid siRNA degradation and reduce the toxicity and adverse effects of chemotherapy medicine.

RESULTS

In this paper, a highly efficient AS1411 aptamer modified, dsDNA and MMP-2 cleavable peptide-fabricated gold nanocage vehicle, which could load doxorubicin hydrochloride (DOX) and siRNAs to achieve a combination of tumor responsive genetic therapy, chemotherapy, and photothermal treatment is presented. Our results show that this combined treatment achieved targeted gene silencing and tumor inhibition. After nearly one month of treatment with DOX-loaded Au-siRNA-PAA-AS1411 nanoparticles with one dose every three days in mice, a synergistic effect promoting the eradication of long-lived tumors was observed along with an increased survival rate of mice. The combined genetic, chemotherapeutic, and photothermal treatment group exhibited more than 90% tumor inhibition ratio (tumor signal) and a ~ 67% survival rate compared with a 30% tumor inhibition ratio and a 0% survival rate in the passive genetic treatment group.

CONCLUSIONS

The development of nanocarriers with double-stranded DNA and MMP-2 cleavable peptides provides a new strategy for the combined delivery of gene and chemotherapy medicine. Au-siRNA-PAA-AS1411 exerts high anticancer activities on lung cancer, indicating immense potentials for clinical application.

Increasing the antitumor efficacy of doxorubicin liposomes with coupling an anti-EGFR affibody in EGFR-expressing tumor models

Epidermal growth factor receptor (EGFR) is overexpressed in a wide range of solid tumors. In this study, we exploited a high-affinity EGFR-antagonistic affibody (Z_EGFR) coupled to a doxorubicin loaded pegylated liposome (LS-Dox) for concurrent passive and active targeting of EGFR⁺ A431 tumor cells in vitro and in vivo. The in vitro studies revealed that the Dox liposomes coupled with Z_EGFR (AS-Dox) showed a higher Dox uptake than LS-Dox in EGFR⁺ A431 cells but not in EGFR^- B16F10 cells, resulting in a selectively enhanced cytotoxicity. In vivo, AS-Dox confirmed its long circulation time and efficient accumulation in tumors. This targeted chemotherapy achieved greater tumor suppression. Further, this low-dose but effective targeted treatment reduced systemic toxicity such as body weight loss and organ injury demonstrated by H&E staining. Thus, selective targeting of LS-Dox coupled with Z_EGFR enhanced antitumor effects and improved systemic safety. These results demonstrated that LS-Dox coupled with Z_EGFR might be developed as a potential tool for therapy of EGFR⁺ tumors.

Recent advances of nanomedicines for liver cancer therapy

This review highlights recent advancements in nanomedicines for liver cancer therapy.

[Synthesis and cell biological properties of polyaspartic acid drug/gene vector]

OBJECTIVE

Taking polysuccinimide as the main chain, amine side chain and alkyl side chain were grafted to prepare the drug/gene co-delivery vector. The property of the polymers with various side links were investigated to select an optimal vector.

METHODS

Poly-D, L-polysuccinimide was synthesized by polymerization reaction of D, L-aspartic acid as monomer. Therefore, N, N-dimethylenedipropyl-triamine and 3, 3'-diaminodipropylamine were grafted with dodecylamine/adecylamine/octadecylamine at different proportions by ring-opening reaction to obtain amphiphilic PEECs. The structure of the material was confirmed by ¹H NMR; the particle size and surface potential of the micelles were measured by dynamic light scattering; the critical micelle concentration (CMC) was determined by pyrene fluorescent probe; the RNA blocking ability was characterized by agarose gel electrophoresis; the release behavior of the PEECs was examined and the cytotoxicity, cellular uptake and gene silencing efficiency of the PEECs were studied at the cellular level.

RESULTS

A series of PEECs with different grafting rates was successfully synthesized. The particle sizes and surface potential of the PEEC derived micelles were between 250 nm and 350 nm and 27 mV and 45 mV, respectively, with a small CMC value. The RNA binding ratio of PEECs was at a mass ratio of about 0.8:1. MTT assay demonstrated that PEEC micelles had certain cytotoxicity. PEECs had excellent micelle formation, drug-loading and gene binding abilities, particularly, PEEC₁₆-2 showed high gene silencing efficiency at the cellular level.

CONCLUSIONS

PEECs are able to co-delivery drug and gene, and PEEC₁₆-2 micelles have the best ability of drug encapsulation and gene delivery.

Nanomedicine as a putative approach for active targeting of hepatocellular carcinoma

The effectiveness of chemotherapy in hepatocellular carcinoma (HCC) is restricted by chemo-resistance and systemic side effects. To improve the efficacy and safety of chemotherapeutics in HCC management, scientists have attempted to deliver these drugs to malignant tissues using targeted carriers as nanoparticles (NPs). Among the three types of NPs targeting (active, passive, and stimuli-responsive), active targeting is the most commonly investigated in HCC treatment. Despite the observed promising results so far, clinical research on nanomedicine targeting for HCC treatment still faces many challenges.These include batch-to-batch physicochemical properties' variations, limiting large scale production and insufficient data on human and environmental toxicities. This review summarized the characteristics of different nanocarriers, ligands, targeted receptors on HCC cells and provided recommendations to overcome the challenges, facing this novel line of treatment for HCC.

Novel polyethyleneimine-R8-heparin nanogel for high-efficiency gene delivery in vitro and in vivo

Gene therapy is an efficient and promising approach to treat malignant tumors. However, protecting the nucleic acid from degradation in vivo and efficient delivering it into tumor cells remain challenges that require to be addressed before gene therapy could be applied in clinic. In this study, we prepared novel polyethyleneimine-RRRRRRRR(R8)-heparin (HPR) nanogel as an efficient gene delivery system, which consists of heparin and cell penetrating peptide R8 grafted low-molecule-weight polyethyleneimine (PEI). Due to the shielding effect of heparin, crosslinking PEI-R8 with heparin was designed to diminish the toxicity of the gene delivery system. Meanwhile, a partial of R8 peptide which located on the surface of HPR nanogel could significantly enhance the cellular uptake. The formed HPR/pDNA complex exhibited effective endolysosomal escape, resulting in a high-efficiency transfection. Furthermore, the HPR could deliver the plasmid which could transcribe human TNF-related apoptosis inducing ligand (phTRAIL), into HCT-116 cells and induce significant cell apoptosis. In addition, HPR/phTRAIL complex showed satisfactory antitumor activity in abdominal metastatic colon carcinoma model. Finally, the antitumor mechanism of HPR/phTRAIL was also explored by western blot and histological analysis. The above results suggested that the HPR nanogel could serve as a promising gene delivery system.

Novel carbamate-linked quaternary ammonium lipids containing unsaturated hydrophobic chains for gene delivery

In this paper, two novel carbamate-linked quaternary ammonium lipids (MU18: a lipid with a mono-ammonium head; GU18: a lipid with a Gemini-ammonium head) containing unsaturated hydrophobic chains were designed and synthesized. The chemical structures of the synthetic lipids were characterized by infrared spectrum, ESI-MS, ¹H NMR, ¹³C NMR, and HPLC. For investigating the effect of unsaturation on gene delivery, the previous reported saturated cationic liposomes (MS18 and GS18) were used as comparison. Cationic liposomes were prepared by using these cationic lipids and neutral lipid DOPE at the molar ratio of 1:1. Particle sizes and zeta potentials of the cationic liposomes were studied to show that they were suitable for gene transfection. The binding abilities of the cationic liposomes were investigated by gel electrophoresis at various N/P ratios from 0.5/1 to 8/1. The results indicated that the binding ability of GU18 was much better than MU18 and the saturated cationic liposomes (MS18 and GS18). DNA transfection of these liposomes comparable to commercially available reagent (DOTAP) was achieved in vitro against Hela, HepG-2 and NCI-H460 cell lines. GU18 showed higher transfection at the N/P ratio of 3/1 than other cationic liposomes and the positive control, DOTAP. All of the liposomes presented a relatively low cytotoxicity, which was measured by MTT. Therefore, the synthetic lipids bearing unsaturated hydrophobic chains and Gemini-head could be promising candidates for gene delivery.

EGFR-targeted multifunctional polymersomal doxorubicin induces selective and potent suppression of orthotopic human liver cancer in vivo

Liver cancer is a globally leading malignancy that has a poor five-year survival rate of less than 20%. The systemic chemotherapeutics are generally ineffective for liver cancers partly due to fast clearance and low tumor uptake. Here, we report that GE11 peptide functionalized polymersomal doxorubicin (GE11-PS-DOX) effectively targets and inhibits epidermal growth factor receptor (EGFR)-positive SMMC7721 orthotopic human liver tumor xenografts in mice. GE11-PS-DOX with a GE11 surface density of 10% displayed a high drug loading of 15.4 wt%, a small size of 78 nm, and glutathione-triggered release of DOX. MTT assays, flow cytometry and confocal microscopy studies revealed that GE11-PS-DOX mediated obviously more efficient DOX delivery into SMMC7721 cells than the non-targeting PS-DOX and clinically used liposomal doxorubicin (Lipo-DOX) controls. The in vivo studies showed that GE11-PS-DOX had a long circulation time and an extraordinary accumulation in the tumors (13.3 %ID/g). Interestingly, GE11-PS-DOX caused much better treatment of SMMC7721 orthotopic liver tumor-bearing mice as compared to PS-DOX and Lipo-DOX. The mice treated with GE11-PS-DOX (12 mg DOX equiv./kg) exhibited a significantly improved survival rate (median survival time: 130 days versus 70 and 38 days for PS-DOX at 12 mg DOX equiv./kg and Lipo-DOX at 6 mg DOX equiv./kg, respectively) and achieved 50% complete regression. Notably, GE11-PS-DOX induced obviously lower systemic toxicity than Lipo-DOX. EGFR-targeted multifunctional polymersomal doxorubicin with improved efficacy and safety has a high potential for treating human liver cancers.

STATEMENT OF SIGNIFICANCE

Liver cancer is one of the top five leading causes of cancer death worldwide. The systemic chemotherapeutics and biotherapeutics generally have a low treatment efficacy for hepatocellular carcinoma partly due to fast clearance and/or low tumor uptake. Nanomedicines based on biodegradable micelle and polymersomes offer a most promising treatment for malignant liver cancers. Their clinical effectiveness remains, however, suboptimal owing to issues like inadequate systemic stability, low tumor accumulation and selectivity, and poor control over drug release. Here we report that GE11 peptide-functionalized, disulfide-crosslinked multifunctional polymersomal doxorubicin (GE11-PS-DOX) can effectively suppress the growth of orthotopic SMMC7721 human liver tumors in nude mice. They showed significantly decreased systemic toxicity and improved mouse survival rate with 3.4-fold longer median survival time as compared to clinically used pegylated liposomal doxorubicin (Lipo-DOX) and achieving 50% complete regression. GE11-PS-DOX, based on PEG-PTMC is biodegradable, nontoxic, and easy to prepare, appears as a safe, robust, versatile and all-function-in-one nanoplatform that has a high potential in targeted chemotherapy of EGFR expressed hepatocellular carcinoma.

Ligand-based targeted therapy: a novel strategy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with high morbidity and mortality worldwide. Chemotherapy is recommended to patients with intermediate or advanced stage cancer. However, the conventional chemotherapy yields low desired response rates due to multidrug resistance, fast clearance rate, nonspecific delivery, severe side effects, low drug concentration in cancer cells, and so on. Nanoparticle-mediated targeted drug delivery system can surmount the aforementioned obstacles through enhanced permeability and retention effect and active targeting as a novel approach of therapeutics for HCC in recent years. The active targeting is triggered by ligands on the delivery system, which recognize with and internalize into hepatoma cells with high specificity and efficiency. This review focuses on the latest targeted delivery systems for HCC and summarizes the ligands that can enhance the capacity of active targeting, to provide some insight into future research in nanomedicine for HCC.

pH-Responsive Hyaluronic Acid-Based Mixed Micelles for the Hepatoma-Targeting Delivery of Doxorubicin

The tumor targetability and stimulus responsivity of drug delivery systems are crucial in cancer diagnosis and treatment. In this study, hepatoma-targeting mixed micelles composed of a hyaluronic acid–glycyrrhetinic acid conjugate and a hyaluronic acid-l-histidine conjugate (HA–GA/HA–His) were prepared through ultrasonic dispersion. The formation and characterization of the mixed micelles were confirmed via ¹H-NMR, particle size, and ζ potential measurements. The in vitro cellular uptake of the micelles was evaluated using human liver carcinoma (HepG2) cells. The antitumor effect of doxorubicin (DOX)-loaded micelles was investigated in vitro and in vivo. Results indicated that the DOX-loaded HA–GA/HA–His micelles showed a pH-dependent controlled release and were remarkably absorbed by HepG2 cells. Compared with free DOX, the DOX-loaded HA–GA/HA–His micelles showed a higher cytotoxicity to HepG2 cells. Moreover, the micelles effectively inhibited tumor growth in H22 cell-bearing mice. These results suggest that the HA–GA/HA–His mixed micelles are a good candidate for drug delivery in the prevention and treatment of hepatocarcinoma.

Antibody-targeted biodegradable nanoparticles for cancer therapy

The use of nanotechnology has great potentials to revolutionize the future cancer diagnosis and therapy. In this context, various nanoparticles (NPs) have been developed for targeted delivery of diagnostic/therapeutic agents to the tumor sites, which thus result in greater efficacy and much less side effects. The targeting property of NPs is often achieved by functionalizing their surface with tumor-specific ligands, such as antibodies, peptides, small molecules and oligonucleotides. In this review, we will discuss recent progress in the multifunctional design of antibody-targeted NPs with a special focus on liposomal, polymeric and protein-based delivery systems.

Chlorambucil gemcitabine conjugate nanomedicine for cancer therapy

Self-assembly of anticancer small molecules into nanostructures may represent an attractive approach to improve the treatment of experimental solid tumors. As a proof of concept, we designed and synthesized the conjugate prodrug of hydrophilic gemcitabine by its covalent coupling to hydrophobic chlorambucil via a hydrolyzable ester linkage. The resulting amphiphilic conjugates self-assembled into nanoparticles in water and exhibited significant anticancer activity in vitro against a variety of human cancer cells. In vivo anticancer activity of these nanoparticles has been tested on subcutaneous grafted SMMC-7721 hepatocellular carcinoma model. Such chlorambucil gemcitabine conjugate nanomedicine should have potential applications in cancer therapy.

Peptide GE11-Polyethylene Glycol-Polyethylenimine for targeted gene delivery in laryngeal cancer

The objective of this study was to evaluate the possibility of using GE11-polyethylene glycol-polyethylenimine (GE11-PEG-PEI) for targeted gene delivery to treat epidermal growth factor receptor (EGFR)-overexpressing laryngeal cancer. This study described the design, characterization, and in vitro and in vivo study of the nanocarrier GE11-PEG-PEI for gene delivery to treat laryngeal cancer. Analysis of the sizes and zeta potentials indicated that the formation of PEGylated complexes was dependent on the N/P ratio, and these complexes were capable of binding plasmid DNA and condensing DNA into small positively charged nanoparticles. The results also revealed that GE11-PEG-PEI had a weaker effect on cell survival in vitro. Gene transfection was performed on human laryngeal cancer Hep-2 cells in vitro and in vivo. Both the in vitro and in vivo results demonstrated that GE11-PEG-PEI had greater transfection efficiency than mPEG-PEI. Compared with mPEG-PEI/pORF-hTRAIL and saline, GE11-PEG-PEI/pORFh-TRAIL significantly (p < 0.05) reduced tumor growth in nude mice with laryngeal cancer. Moreover, the GE11-PEG-PEI/pORF-hTRAIL-treated groups showed more apoptosis than the mPEG-PEI/pORF-hTRAIL-treated groups. Therefore, our results showed that the peptide GE11 conjugated to PEG-PEI delivered significantly more genes to EGFR-overexpressing laryngeal cancer cells in vivo, indicating that GE11-PEG-PEI may be a suitable gene vector for treating EGFR-overexpressing laryngeal cancer.

Reversibly cross-linked polyplexes enable cancer-targeted gene delivery via self-promoted DNA release and self-diminished toxicity

Polycations often suffer from the irreconcilable inconsistency between transfection efficiency and toxicity. Polymers with high molecular weight (MW) and cationic charge feature potent gene delivery capabilities, while in the meantime suffer from strong chemotoxicity, restricted intracellular DNA release, and low stability in vivo. To address these critical challenges, we herein developed pH-responsive, reversibly cross-linked, polyetheleneimine (PEI)-based polyplexes coated with hyaluronic acid (HA) for the effective and targeted gene delivery to cancer cells. Low-MW PEI was cross-linked with the ketal-containing linker, and the obtained high-MW analogue afforded potent gene delivery capabilities during transfection, while rapidly degraded into low-MW segments upon acid treatment in the endosomes, which promoted intracellular DNA release and reduced material toxicity. HA coating of the polyplexes shielded the surface positive charges to enhance their stability under physiological condition and simultaneously reduced the toxicity. Additionally, HA coating allowed active targeting to cancer cells to potentiate the transfection efficiencies in cancer cells in vitro and in vivo. This study therefore provides an effective approach to overcome the efficiency-toxicity inconsistence of nonviral vectors, which contributes insights into the design strategy of effective and safe vectors for cancer gene therapy.

Polymeric nanoparticles for targeted treatment in oncology: current insights

Chemotherapy, a major strategy for cancer treatment, lacks the specificity to localize the cancer therapeutics in the tumor site, thereby affecting normal healthy tissues and advocating toxic adverse effects. Nanotechnological intervention has greatly revolutionized the therapy of cancer by surmounting the current limitations in conventional chemotherapy, which include undesirable biodistribution, cancer cell drug resistance, and severe systemic side effects. Nanoparticles (NPs) achieve preferential accumulation in the tumor site by virtue of their passive and ligand-based targeting mechanisms. Polymer-based nanomedicine, an arena that entails the use of polymeric NPs, polymer micelles, dendrimers, polymersomes, polyplexes, polymer–lipid hybrid systems, and polymer–drug/protein conjugates for improvement in efficacy of cancer therapeutics, has been widely explored. The broad scope for chemically modifying the polymer into desired construct makes it a versatile delivery system. Several polymer-based therapeutic NPs have been approved for clinical use. This review provides an insight into the advances in polymer-based targeted nanocarriers with focus on therapeutic aspects in the field of oncology.

Active radar guides missile to its target: receptor-based targeted treatment of hepatocellular carcinoma by nanoparticulate systems. Tumour Biol. 2015;36:55-67. [PMID: 25424700 DOI: 10.1007/s13277-014-2855-3]

Patients with hepatocellular carcinoma (HCC) usually present at advanced stages and do not benefit from surgical resection, so drug therapy should deserve a prominent place in unresectable HCC treatment. But chemotherapy agents, such as doxorubicin, cisplatin, and paclitaxel, frequently encounter important problems such as low specificity and non-selective biodistribution. Recently, the development of nanotechnology led to significant breakthroughs to overcome these problems. Decorating the surfaces of nanoparticulate-based drug carriers with homing devices has demonstrated its potential in concentrating chemotherapy agents specifically to HCC cells. In this paper, we reviewed the current status of active targeting strategies for nanoparticulate systems based on various receptors such as asialoglycoprotein receptor, transferrin receptor, epidermal growth factor receptor, folate receptor, integrin, and CD44, which are abundantly expressed on the surfaces of hepatocytes or liver cancer cells. Furthermore, we pointed out their merits and defects and provided theoretical references for further research.

Acetylcholinesterase overexpression mediated by oncolytic adenovirus exhibited potent anti-tumor effect

Background

Acetylcholinesterase (AChE) mainly functions as an efficient terminator for acetylcholine signaling transmission. Here, we reported the effect of AChE on gastric cancer therapy.

Methods

The expression of AChE in gastric cancerous tissues and adjacent non-cancerous tissues was examined by immunohistochemistry. Gastric cancer cells were treated with AChE delivered by replication-deficient adenoviral vector (Ad.AChE) or oncolytic adenoviral vector (ZD55-AChE), respectively, followed by measurement of cell viability and apoptosis by MTT assay and apoptosis detection assays. In vivo, the tumor growth of gastric cancer xenografts in mice treated with Ad.AChE or ZD55-AChE (1 × 10⁹ PFU) were measured. In addition, the cell viability of gastric cancer stem cells treated with Ad.AChE or ZD55-AChE were evaluated by MTT assay.

Results

A positive correlation was found between higher level of AChE expression in gastric cancer patient samples and longer survival time of the patients. Ad.AChE and ZD55-AChE inhibited gastric cancer cell growth, and low dose of ZD55-AChE induced mitochondrial pathway of apoptosis in cells. ZD55-AChE repressed tumor growth in vivo, and the anti-tumor efficacy is greater than Ad.AChE. Moreover, ZD55-AChE suppressed the growth of gastric cancer stem cells.

Conclusion

ZD55-AChE represented potential therapeutic effect for human gastric cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-668) contains supplementary material, which is available to authorized users.

Trigger-responsive, fast-degradable poly(β-amino ester)s for enhanced DNA unpackaging and reduced toxicity

Poly(β-amino ester)s (PBAEs) represent an important class of cationic gene delivery materials which, however, suffer from uncontrolled DNA release due in part to the slow degradation of their polyester backbone. Additionally, PBAEs with high molecular weight (MW) also show considerable toxicities. In this study, we designed and developed PBAEs with trigger-responsive domains built-in polymer backbones that can be rapidly cleaved upon external UV light triggering to promote intracellular DNA release as well as reduce material toxicity. Photo-responsive PBAEs were prepared via polyaddition of (2-nitro-1,3-phenylene)bis(methylene) diacrylate and a bifunctional amine. The nitrobenzene moiety was placed in each repeating unit of the PBAE to allow fast response to external UV irradiation, and thus the ester linkers were cleaved and the polymers were degraded within several minutes upon UV irradiation. Cationic PBAEs with high MWs were able to mediate effective intracellular gene delivery, while upon UV irradiation post-transfection, enhanced DNA unpackaging and reduced material toxicity were observed, which collectively contributed to greatly improved transfection efficiencies in various mammalian cell types tested. This strategy allows precise manipulation of material toxicity and gene release profiles of PBAEs, and thus provides an effective design approach to address critical issues in non-viral gene delivery.

The effect of side-chain functionality and hydrophobicity on the gene delivery capabilities of cationic helical polypeptides

The rational design of effective and safe non-viral gene vectors is largely dependent on the understanding of the structure-property relationship. We herein report the design of a new series of cationic, α-helical polypeptides with different side charged groups (amine and guanidine) and hydrophobicity, and mechanistically unraveled the effect of polypeptide structure on the gene delivery capability. Guanidine-containing polypeptides displayed superior membrane activities to their amine-containing analogues via the pore formation mechanism, and thus possessed notably higher transfection efficiencies. Elongating the hydrophobic side chain also potentiated the membrane activities of the polypeptides, while at the meantime caused higher cytotoxicities. Upon an optimal balance between membrane activity and cytotoxicity, maximal transfection efficiency was achieved which outperformed commercial reagent Lipofectamine™ 2000 (LPF2000) by 3-6 folds. This study thus provides mechanistic insights into the rational design of non-viral gene delivery vectors, and the best-performing materials identified also serve as a promising addition to the existing systems.

Synergetic effect of SLN-curcumin and LDH-5-Fu on SMMC-7721 liver cancer cell line

Curcumin and 5-Fluorouracil (5-Fu) have been reported to have anticancer potentials and show certain synergetic effect on some cancer cell lines. However, the poor bioavailability and rapid metabolism limited their medical application. In this study, we encapsulated curcumin with solid lipid nanoparticles (SLN), 5-Fu with Layered double hydroxides (LDHs) separately and tested its properties and anticancer potentials. SLN-curcumin and LDH-5-Fu were determined to be 100 and 60 nm by Transmission Electron Microscopy detection, and the loading efficiency were 28%±2.5% and 16.7%±1.8%, individually. Furthermore, SLN-curcumin and LDH-5-Fu showed a significantly synergetic effect on SMMC-7721 cell stronger than plain drugs together, of which the Idrug loaded nano-carriers was only 0.315. FACS analysis revealed that the combination of SLN-curcumin and LDH-5-Fu induced 80.1% apoptosis in SMMC-7721 cells, which were 1.7-folds of the sum of the two plain drug loaded carriers. The results demonstrated the significant synergetic anticancer potentials of nano-encapsulated curcumin and 5-Fu, which could be further explored for the treatment of other carcinoma.

Trends in polymeric delivery of nucleic acids to tumors

Delivery of nucleic acids to tumors has received extensive attention in the past few decades since these molecules are capable of treating disease by modulating the source of abnormalities. Although high efficiency and low toxicity of numerous delivery systems for nucleic acids have been approved frequently with in vitro assays, contradictions have been observed in many cases between these results and what has occurred in the dynamic in vivo situation. Filling this gap seems to be crucial for further preclinical development of such systems. In this paper, we discuss various barriers which polymeric DNA or siRNA nanoparticles encounter upon systemic administration with an aim to assist in designing more relevant in vitro assays. Furthermore, individual considerations concerning delivery of DNA and siRNA have been addressed.