Co-delivery of glycyrrhizin and doxorubicin by alginate nanogel particles attenuates the activation of macrophage and enhances the therapeutic efficacy for hepatocellular carcinoma.

Nanocarrier drug delivery systems (NDDS) have been paid more attention over conventional drug delivery system for cancer therapy. However, the efficacy is hampered by the fast clearance of activated macrophage from the blood circulation system. In this study, glycyrrhizin (GL) was introduced into alginate (ALG) nanogel particles (NGPs) to construct multifunctional delivery vehicle to decrease the fast clearance of activated macrophage and enhance the anticancer efficacy with the combination therapy of GL and doxorubicin (DOX). Methods: We firstly synthesized the GL-ALG NGPs with intermolecular hydrogen bond and ionic bond as the multifunctional delivery vehicle. The immune response and phagocytosis of macrophage on GL-ALG NGPs were investigated on RAW 264.7 macrophages. The pharmacokinetic study of DOX loaded in GL-ALG NGPs was performed in rats. The active targeting effects of GL-ALG NGPs were further studied on hepatocellular carcinoma cell (HepG2) and H22 tumor-bearing mice. Moreover, the anticancer molecular mechanism of DOX/GL-ALG NGPs was investigated on HepG2 cells in vitro and tumor-bearing mice in vivo. Results: GL-ALG NGPs could not only avoid triggering the immuno-inflammatory responses of macrophages but also decreasing the phagocytosis of macrophage. The bioavailability of DOX was increased about 13.2 times by DOX/GL-ALG NGPs than free DOX in blood. The mice with normal immune functions used in constructing the tumor-bearing mice instead of the nude mouse also indicated the good biocompatibility of NGPs. GL-mediated ALG NGPs exhibited excellent hepatocellular carcinoma targeting effect in vitro and in vivo. The results suggested that the anticancer molecular mechanism of the combination therapy of glycyrrhizin and doxorubicin in ALG NGPs was performed via regulating apoptosis pathway of Bax/Bcl-2 ratio and caspase-3 activity, which was also verified in H22 tumor-bearing mice. Conclusion: DOX/GL-ALG NGPs could attenuate the activation of macrophage and enhance the therapeutic efficacy for hepatocellular carcinoma. Our results suggest that the combination therapy would provide a new strategy for liver cancer treatment.

Enhanced antitumor immunity by targeting dendritic cells with tumor cell lysate-loaded chitosan nanoparticles vaccine.

Whole tumor cell lysates (TCL) have been implemented as tumor antigens for cancer vaccine development, although clinical outcomes of TCL-based antitumor immunotherapy remain unsatisfactory. In order to improve the efficacy of TCL-based vaccines, biomaterials have been employed to enhance antigen delivery and presentation. Here, we have developed chitosan nanoparticles (CTS NPs) with surface mannose (Man) moieties for specific dendritic cells (DCs) targeting (Man-CTS NPs). The Man-CTS NPs were then loaded with TCL generated from B16 melanoma cells (Man-CTS-TCL NPs) for in vitro and in vivo assessment. Potency of the Man-CTS-TCL NPs as cancer vaccine was also assessed in vivo by immunization of mice with Man-CTS-TCL NPs followed by re-challenge with B16 melanoma cell inoculation. We have shown here that Man-CTS-TCL NPs promote bone marrow-derived dendritic cells (BMDCs) maturation and antigen presentation in vitro. In vivo evaluation further demonstrated that the Man-CTS-TCL NPs were readily taken up by endogenous DCs within the draining lymph node (DLN) following subcutaneous administration accompanied by increasing in serum IFN-γ and IL-4 levels. Tumor growth was also significantly delayed in mice primed with Man-CTS-TCL NPs vaccine, attributable at least in part to cytotoxic T lymphocytes response. Moreover, Man-CTS-TCL NPs vaccine also exhibited therapeutic effects in mice with melanoma. Thus, we report here the Man-CTS-TCL NPs as effective anti-tumor vaccine for cancer immunotherapy.

In vitro evaluation of polymeric micelles based on hydrophobically-modified sulfated chitosan as a carrier of doxorubicin.

Four types of doxorubicin (DOX)-loaded polymeric micelles based on hydrophobically-modified sulfated chitosan (SCTS) were prepared. The hydrophobic group was composed of glycyrrhetinic acid (GA), cholic acid, stearic acid (SA) or lauric aldehyde. DOX encapsulation depended on several parameters, including the degree of substitution of the sulfate group and the hydrophobic group, and the type of hydrophobic group. Of these micelles, GA-SCTS micelles had the best capability to solubilize DOX. In addition, GA-SCTS micelles had the ability to target HepG(2) cells, and the IC50 for DOX-loaded GA-SCTS micelles was 54.7 ng/mL, which was much lower than that of the other micelles. Further studies on the DOX-loaded GA-SCTS micelles showed that they were stable in salt and protein solutions, in cell culture media, and during long-term storage (6 months). Based on these results, these micelles may be a promising DOX-encapsulated formulation, particularly, GA-SCTS as a potential vehicle for liver-targeted delivery.

Self-assembly and liver targeting of sulfated chitosan nanoparticles functionalized with glycyrrhetinic acid.

A drug carrier based on glycyrrhetinic acid-modified sulfated chitosan (GA-SCTS) was synthesized. The glycyrrhetinic acid (GA) acted as both a hydrophobic group and a liver-targeting ligand. The GA-SCTS micelles displayed rapid and significant ability to target the liver in vivo. The IC(50) for doxorubicin (DOX)-loaded GA-SCTS micelles (DOX/SA-SCTS micelles) against HepG2 cells was 54.7 ng/mL, which was extremely lower than the amount of no-GA-modified DOX-loaded micelles. In addition, DOX/SA-SCTS micelles could target specifically the liver cancer cells. They had higher affinity for the liver cancer cells (HepG2 cells) than for the normal liver cells (Chang liver cells). There was nearly 2.18-fold improvement in uptake of the DOX/SA-SCTS micelles by HepG2 cells than that by Chang liver cells. These results indicate that GA-SCTS is not only an excellent carrier for drugs, but also a potential vehicle for liver-cancer targeting.

Glycyrrhetinic acid-functionalized degradable micelles as liver-targeted drug carrier.

Recently, many efforts have been devoted to investigating the application of functionalized micelles as targeted drug delivery carriers. In this study, glycyrrhetinic acid (GA, a liver targeting ligand) modified poly(ethylene glycol)-b-poly(γ-benzyl L-glutamate) micelles were prepared and evaluated as a potential liver-targeted drug carrier. The aggregation behavior, stability, size and morphology of the micelles were investigated. Anticancer drug doxorubicin (DOX) was encapsulated in the micelles. The drug release profile, in vivo distribution and the cytotoxicity against hepatic carcinoma QGY-7703 cells of DOX-loaded micelles were studied. The results indicated that the release profile was pH-dependent with Fickian diffusion kinetics. The micelles were remarkably targeted to the liver, inducing a 4.9-fold higher DOX concentration than that for free DOX · HCl. The DOX-loaded micelles exhibited almost twofold more potent cytotoxicity compared with DOX · HCl, and the cytotoxicity was time- and dosage-dependent. These results suggest that GA-functionalized micelles represent a promising carrier for drug delivery to the liver.

Glycyrrhetinic acid-modified chitosan/poly(ethylene glycol) nanoparticles for liver-targeted delivery.

A liver-targeted drug delivery carrier, composed of chitosan/poly(ethylene glycol)-glycyrrhetinic acid (CTS/PEG-GA) nanoparticles, was prepared by an ionic gelation process, in which glycyrrhetinic acid (GA) acted as the targeting ligand. The formation and characterization of these nanoparticles were confirmed by FT-IR, dynamic light scattering (DLS) and zeta potential measurements. The biodistribution of the nanoparticles was assessed by single-photon emission computed tomography (SPECT), and the cellular uptake was evaluated using human hepatic carcinoma cells (QGY-7703 cells). The anti-neoplastic effect of the doxorubicin.HCl-loaded nanoparticles (DOX-loaded nanoparticles) was also investigated in vitro and in vivo. The results showed that the CTS/PEG-GA nanoparticles were remarkably targeted to the liver, and keep at a high level during the experiment. The accumulation in the liver was 51.3% at 3 h after injection; this was nearly 2.6 times that obtained with the CTS/PEG nanoparticles. The DOX-loaded nanoparticles were greatly cytotoxic to QGY-7703 cells, and the IC(50) (50% inhibitory concentration) for the free doxorubicin.HCl (DOX.HCl) and the DOX-loaded CTS/PEG-GA nanoparticles were 47 and 79 ng/mL, respectively. Moreover, the DOX-loaded CTS/PEG-GA nanoparticles could effectively inhibit tumor growth in H22 cell-bearing mice.