Dual-Loaded Liposomes Tagged with Hyaluronic Acid Have Synergistic Effects in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the most lethal subtypes of breast cancer. Although chemotherapy is considered the most effective strategy for TNBC, most chemotherapeutics in current use are cytotoxic, meaning they target antiproliferative activity but do not inhibit tumor cell metastasis. Here, a TNBC-specific targeted liposomal formulation of epalrestat (EPS) and doxorubicin (DOX) with synergistic effects on both tumor cell proliferation and metastasis is described. These liposomes are biocompatible and effectively target tumor cells owing to hyaluronic acid (HA) modification on their surface. This active targeting, mediated by CD44-HA interaction, allows DOX and EPS to be delivered simultaneously to tumor cells in vivo, where they suppress not only TNBC tumor growth and the epithelial-mesenchymal transition, but also cancer stem cells, which collectively suppress tumor growth and metastasis of TNBC and may also act to prevent relapse of TNBC.

Cell-Penetrating Peptide and Transferrin Co-Modified Liposomes for Targeted Therapy of Glioma.

Glioma is one of the most aggressive and common malignant brain tumors. Due to the presence of the blood-brain barrier (BBB), the effectiveness of therapeutics is greatly affected. In this work, to develop an efficient anti-glioma drug with targeting and which was able to cross the BBB, cell-penetrating peptides (R8) and transferrin co-modified doxorubicin (DOX)-loaded liposomes (Tf-LPs) were prepared. Tf-LPs possessed a spherical shape and uniform size with 128.64 nm and their ξ-potential was 6.81 mV. Tf-LPs were found to be stable in serum within 48 h. Uptake of Tf-LPs in both U87 and GL261 cells was analyzed by confocal laser scanning microscopy and by flow cytometry. Tf-LPs were efficiently taken up by both U87 and GL261 cells. Moreover, Tf-LPs exhibited sustained-release. The cumulative release of DOX from Tf-LPs reached ~50.0% and showed excellent anti-glioma efficacy. Histology of major organs, including brain, heart, liver, spleen, lungs and kidney, and the bodyweight of mice, all indicated low toxicity of Tf-LPs. In conclusion, Tf-LPs showed great promise as an anti-glioma therapeutic agent.

Multifunctional drug carrier based on PEI derivatives loaded with small interfering RNA for therapy of liver cancer.

Gene therapy strategies for liver cancer have broad application prospects but still lack a stable and efficient delivery vehicle. To overcome this obstacle, we designed a multifunctional gene delivery vector, sTPssOLP, which was based on oleylamine (OA)-modified disulfide-containing polyethylenimine (PEI) and incorporated into lipids to prepare a lipid nanoparticle. sTPssOLP consisted of the core of PEI derivative and cationic lipids bound to siRNA. The modified polyethylene glycol (PEG) and transferrin (Tf) were partially embedded in the phospholipid bilayer through the lipid and the other as the outer shell. The aim was to use the redox responsiveness of disulfide to trigger siRNA release in cytoplasm to enhance transfection efficiency. Pegylated lipids and Tf focus on increasing cycle life in the body and increasing accumulation at the tumor site of the carrier. In addition, two vectors were prepared as controls, one based on a PEI derivative containing no disulfide bond (POLP) and the other on the surface of the carrier not linked to Tf (PssOLP). PEI derivatives effectively avoid the toxicity problems caused by the use of PEI alone (25 kDa). Meanwhile, it was confirmed by gel retardation experiments that in the presence of dithiothreitol (DTT), the disulfide bond can indeed be reduced and the siRNA entrapped in the vector can be released. Both HepG2 and SMMC had significant uptake of sTPssOLP. The results of intracellular and lysosomal co-localization indicated that sTPssOLP achieved lysosomal escape. RT-PCR and Western blot results also confirmed that sTPssOLP had the best gene silencing activity. In vivo, the tumor inhibition rate of sTPssOLP in nude mice carrying HepG2 xenografts was 56%, which was significantly greater than that of the saline control group. In vivo imaging results showed that fluorescently labeled siRNA loaded in sTPssOLP was able to deliver more to the tumor site. At the same time, it was observed that sTPssOLP did not show significant damage to normal tissues. Therefore, this multifunctional gene delivery vector warrants further investigation.

Cell-penetrating Peptide-coated Liposomes for Drug Delivery Across the Blood-Brain Barrier.

BACKGROUND/AIM: Glioma is a deadly form of brain cancer. Doxorubicin is cytotoxic against glioma cells. However, the blood-brain barrier (BBB) limits its ability to be delivered to the brain. MATERIALS AND METHODS: Liposomes (R8PLP) formed from, 1,2-dioleoyl-3-trimethylammonium-propane chloride (DOTAP), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy-(polyethylene glycol)-2000] (PEG-DSPE), cholesterol and egg phosphatidylcholine (ePC) were modified by cell-penetrating peptide R8 conjugated with oleic acid as a novel method for delivering doxorubicin. The antitumor effect of R8PLP was evaluated by uptake, cytotoxicity and brain accumulation. RESULTS: The size of R8PLP was 95 nm. Doxorubicin was loaded into R8PLP by active loading with more than 95% encapsulation efficiency. Cellular uptake of R8PLP by U87-MG cells was 8.6-fold higher than that of unmodified liposomes. R8PLP reduced cell viability by 16.18% and 18.11% compared to cholesterol-ePC-liposomes and free doxorubicin, respectively, at 3.6 µM after 24 h treatment. The biodistribution of doxorubicin in the brain was significantly improved by R8PLP. The area under the concentration-time curve (AUC0.5-12 h) of R8PLP was 2.4-times higher than that of cholesterol-ePC-PEG-DSPE-liposomes. CONCLUSION: These results suggest that R8-conjugated oleic acid-modified liposomes are effective delivery vehicles for glioma.

Anticancer activity of stoppin based on a novel peptide delivery system.

Stoppin (L1) is a newly identified anticancer peptide, which is a potent p53­MDM2/MDMX inhibitor. Due to its limitation in cell delivery efficiency, a new peptide delivery system was developed based on a nucleic acid­polypeptide­liposome complex and its stability and effectiveness in vitro was investigated. The nucleic acid­stoppin­liposome complex was prepared and characterization of the complex was conducted. The stability of the complex was evaluated by enzyme digestion. Following transfection of the A549 cells with the complex, detection of green fluorescent protein (GFP) and luciferase activity was conducted to evaluate transfection efficiency. In addition, the anticancer activity of the complex was determined by 3­(4,5­dimethyl­thiazolyl­2)­2,5 diphenyltetrazolium bromide assay and apoptosis was detected by flow cytometry. The results indicated that the particle size of the complex was 102±10 nm and the encapsulation rate was ~100% when the ratio of liposome, L1 and plasmid was: 4 µl:1 µg:2 µg. The enzyme digestion experiment demonstrated that the complex was resistant to pancreatic and DNA enzyme degradation, indicating that the complex had biological stability. Cell transfection demonstrated that it had a mutual promotion effect on delivery, which could be confirmed by GFP fluorescence and luciferase assay. The cell­killing efficiency of this novel delivery system was three times higher than with stoppin alone at a low concentration. In conclusion, this novel stoppin peptide delivery system was stable. The nucleic acid­peptide­liposome complex can protect the internal component from the degradation of enzymes, promote entry of the peptide into the cells and enhance the anti­tumor activity of stoppin. Therefore, it is a promising approach for peptide delivery, which can be characterized and visualized using plasmids with GFP or luciferase.