Zhirong Zhong

Effect of a controlled-release drug delivery system made of oleanolic acid formulated into multivesicular liposomes on hepatocellular carcinoma in vitro and in vivo

The aim of the present study was to develop a novel dosage form of multivesicular liposomes for oleanolic acid (OA) to overcome its poor solubility, prolong therapeutic drug levels in the blood, and enhance the antitumor effect on hepatocellular carcinoma. OA-encapsulated multivesicular liposomes (OA-MVLs) were prepared by a double-emulsion method, and the formulation was optimized by the central composite design. The morphology, particle size, and drug-loading efficiency of OA-MVLs were investigated. Furthermore, OA-MVLs were also characterized both in vitro and in vivo. The results showed that OA-MVLs were spherical particles with an average particle size of 11.57 μm and an encapsulation efficiency of 82.3%±0.61%. OA-MVLs exhibited a sustained-release pattern in vitro, which was fitted to Ritger–Peppas equation. OA-MVLs inhibited the growth of human HepG2 cells which was confirmed by the MTT assay and fluorescence microscopy detection. The in vivo release of OA from OA-MVLs exhibited a sustained manner, indicating a longer circulation time compared to OA solution. The in vivo toxicity study indicated that medium-dose OA-MVLs exerted no toxic effect on the hosts. Importantly, OA-MVLs suppressed the growth of murine H22 hepatoma and prolonged the survival of tumor-bearing mice. In conclusion, the poorly soluble OA could be encapsulated into MVLs to form a novel controlled-release drug delivery system. The present study may hold promise for OA-MVLs as a new dosage form for sustained-release drug delivery in cancer therapy.

Mannan-modified Ad5-PTEN treatment combined with docetaxel improves the therapeutic effect in H22 tumor-bearing mice

Background It has been reported that the tumor suppressor gene, PTEN, which is inactivated in many malignant tumors, plays an important role in apoptosis, cell cycle arrest, cell migration, and cell spread. For cancer gene therapy, one of the most important problems is low gene transfection efficiency. Methods In the present study, to take full advantage of adenovirus in gene expression, we prepared mannan-modified recombinant adenovirus using the PTEN gene (Man-Ad5-PTEN) and investigated the effect of Man-Ad5-PTEN combined with docetaxel (Man-Ad5-PTEN-docetaxel) on tumor growth in a murine model of hepatocellular carcinoma. Results Man-Ad5-PTEN effectively suppressed tumor growth and induced significant apoptosis of murine H22 hepatoma in vivo. Apoptosis levels in tumor-bearing mice treated with Man-Ad5-PTEN-docetaxel were significantly higher than those in tumor-bearing mice treated with naked Ad5-PTEN, Man-Ad5-PTEN, or docetaxel alone. Treatment with Man-Ad5-PTEN-docetaxel resulted in a significant inhibitory effect in this tumor model. Compared with the controls treated with phosphate-buffered solution, the tumor inhibition rate with naked Ad5-PTEN, docetaxel, Man-Ad5-PTEN, and Man-Ad5-PTEN-docetaxel was 48.69%, 49.98%, 75.88%, and 96.93%, respectively. Conclusion These results suggest that combined treatment with Man-Ad5-PTEN and other chemotherapeutic agents may be a potent adjuvant therapeutic approach for the treatment of hepatocellular carcinoma.

Aptamer-mediated gene therapy enhanced antitumor activity against human hepatocellular carcinoma in vitro and in vivo

ABSTRACT A recombinant adenovirus carrying the tumor suppressor gene PTEN (Ad5‐PTEN) is an effective antitumor agent against liver cancer. But the application of Ad5‐PTEN has been greatly hindered by its auto‐immunogenicity, non‐specific toxicity to normal tissues, as well as poor stability in blood stream because of neutralizing antibody. Epithelial cell adhesion molecule (EpCAM) is over‐expressed in most solid tumors and it has been identified to be a cancer stem cell surface marker in liver cancer. An RNA aptamer EpDT3 could specially bind with EpCAM and target EpCAM‐positive cells. Therefore, we hypothesized that developing a novel gene delivery system of EpDT3‐modified Ad5‐PTEN could overcome the disadvantages of naked Ad5‐PTEN and enhance the antitumor effect on hepatocellular carcinoma. We took polyethylene glycol (PEG) as a linker to conjugate EpDT3 with Ad5‐PTEN to prepare EpDT3‐PEG‐Ad5‐PTEN (EPAP) by simple chemical synthesis method. We found that the stability of this novel gene delivery system in human blood serum increased about 16‐fold compared to the naked adenovirus. Meanwhile, EPAP enhanced gene expression and cellular uptake in HepG2 cells, and showed significant inhibition in cell proliferation and cell migration against hepatocellular carcinoma cells HepG2 while showing no cytotoxicity to normal liver cells L‐02, compared with Ad5‐PTEN. Importantly, EPAP could induce cell apoptosis and presented superior antitumor activity against aggressive HepG2 xenograft in nude mice but showed no obvious toxicity to the tested mice at the therapy concentration. In conclusion, EpCAM aptamer EpDT3 could significantly enhance the antitumor effect of Ad5‐PTEN with high binding ability to EpCAM‐positive cells HepG2.

GX1-mediated anionic liposomes carrying adenoviral vectors for enhanced inhibition of gastric cancer vascular endothelial cells

Gastric cancer is a highly lethal malignancy and its 5-year survival rate remains depressed in spite of multiple treatment options. Targeting drug delivery to tumor vasculature may be a promising strategy for gastric cancer therapy, for it can block the nutrition source of tumor and inhibit the metastasis and invasion in a certain extent. In present study, we have prepared the drug-targeting delivery system of peptide GX1-mediated anionic liposomes carrying adenoviral vectors (GX1-Ad5-AL), in which the tumor suppressor gene of PTEN was integrated into DNA of Ad5 and the GX1 peptide could play targeting role to vascular of gastric cancer. The inhibition ability of GX1-Ad5-AL to human gastric cancer cell lines (SGC-7901) and human umbilical vein endothelial cells (HUVEC) was evaluated by MTT assay. Further, the cell migration assay was carried out in transwell inserts and the cells uptaking of GX1-Ad5-AL was detected by confocal laser scanning microscopy. The experimental results indicated that the average cell proliferation inhibition rates resulted from the drug delivery system of GX1-Ad5-AL in SGC-7901 and HUVEC were 68.36% and 64.13%, respectively which were higher than that resulted from GX1 or Ad5-AL. Meanwhile, results of cell migration experiment demonstrated that GX1-Ad5-AL could significantly suppress the migration of gastric cancer cell of SGC-7901. Moreover, both the imaging from confocal laser scanning microscopy and the quantitative analysis of fluorescence intensity showed that, GX1-Ad5-AL was more easily uptaken by SGC-7901 cells, as compared to Ad5-AL. Therefore, the formulation of GX1-Ad5-AL was effective for enhancing the inhibition effect and suppressing the migration of gastric cancer vascular endothelial cells.

Targeted delivery of hyaluronic acid-coated solid lipid nanoparticles for rheumatoid arthritis therapy

Abstract Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disease. Long-term, high-dose glucocorticoid therapy can be used to treat the disease, but the fact that the drug distributes systemically can give rise to severe adverse effects. Here we develop a targeted system for treating RA in which the glucocorticoid prednisolone (PD) is encapsulated within solid lipid nanoparticles (SLNs) coated with hyaluronic acid (HA), giving rise to HA-SLNs/PD. HA binds to hyaluronic receptor CD44, which is over-expressed on the surface of synovial lymphocytes, macrophages and fibroblasts in inflamed joints in RA. As predicted, HA-SLNs/PD particles accumulated in affected joint tissue after intravenous injection into mice with collagen-induced arthritis (CIA), and HA-SLNs/PD persisted longer in circulation and preserved bone and cartilage better than free drug or drug encapsulated in SLNs without HA. HA-SLNs/PD reduced joint swelling, bone erosion and levels of inflammatory cytokines in serum. These results suggest that encapsulating glucocorticoids such as PD in HA-coated SLNs may render them safe and effective for treating inflammatory disorders.

Characterization of aptamer-mediated gene delivery system for liver cancer therapy

Liver cancer is a fatal disease with limited therapy options. The recombinant adenovirus expressing tumor-suppressor gene of PTEN (Ad5-PTEN) showed effective antitumor activity against liver cancer. However, its disadvantages produced great limitation on its application, especially its nonspecific and toxicity to normal cells and tissues. The epithelial cell adhesion molecule (EpCAM) is over-expressed in some liver cancer cells and an RNA aptamer EpDT3 could specially target to EpCAM-positive cells. Based on this founding, we aimed to design a kind of gene delivery system of EpDT3-mediated Ad5-PTEN (EpDT3-PEG-Ad5-PTEN, EPAP) in which polyethylene glycol was used to be a linker to conjugate EpDT3 with Ad5-PTEN. This strategy may overcome the disadvantages of naked Ad5-PTEN and enhance the antitumor effect on liver cancer. The SDS-PAGE electrophoresis, TBE-PAGE electrophoresis and fluorescence detection were conducted to confirm the successful preparation of EPAP. Compared with the naked Ad5-PTEN, EPAP showed significant anti-proliferative and anti-migratory activities against HepG2 cells. EPAP also showed selective and precise target ability to EpCAM-positive HepG2 cells in vivo. Therefore, EPAP may be further explored as a novel effective anticancer drug for malignant liver cancer.

Optimized formulation of multivesicular liposomes loaded with oleanolic acid enhanced anticancer effect in vitro

Invasion and metastasis are the main causes leading to the death of patients with hepatocellular carcinoma (HCC). Multivesicular liposomes loaded with oleanolic acid (OA-MVLs) have been well demonstrated to suppress survival, growth and angiogenesis of HCC cells. Emerging evidence demonstrates that OA was able to suppress the invasion of HCC cells by down-regulating myocyte enhancer factor-2. We hypothesized that the optimized OA-MVLs could inhibit the migration and invasion of HCC cells. In this study, we utilized central composite design and response surface methodology to assess the influence of some parameters on particle size and encapsulation efficiency and obtain the optimized formulation of OA-MVLs. Subsequently, the human HCC cell lines SMMC-7721 and HepG2 were treated with different doses of OA-MVLs and OA, respectively. Cellular survival, adhesion, migration and invasion in vitro were evaluated. We found that the optimized OA-MVLs significantly decreased the ability of HCC cells to adhere, migrate and invade in vitro. Furthermore, OA-MVLs significantly inhibited the survival of HCC cells at 160 µmol/L but showed no obvious inhibition effect on the cell vitality of normal liver cells. Our findings indicate that OA-MVLs did inhibit the cell survival, adhesion, invasion and metastasis of HCC cells in vitro. Although the involved mechanisms are still unclear, our findings can contribute to a better development of a preventive and therapeutic strategy for human HCC.