Glycyrrhetinic acid-modified chitosan nanoparticles enhanced the effect of 5-fluorouracil in murine liver cancer model via regulatory T-cells

Strategies for Solubility and Bioavailability Enhancement and Toxicity Reduction of Norcantharidin

Cantharidin (CTD) is the main active ingredient isolated from Mylabris, and norcantharidin (NCTD) is a demethylated derivative of CTD, which has similar antitumor activity to CTD and lower toxicity than CTD. However, the clinical use of NCTD is limited due to its poor solubility, low bioavailability, and toxic effects on normal cells. To overcome these shortcomings, researchers have explored a number of strategies, such as chemical structural modifications, microsphere dispersion systems, and nanodrug delivery systems. This review summarizes the structure-activity relationship of NCTD and novel strategies to improve the solubility and bioavailability of NCTD as well as reduce the toxicity. This review can provide evidence for further research of NCTD.

The Dual Role of the Liver in Nanomedicine as an Actor in the Elimination of Nanostructures or a Therapeutic Target

The development of nanostructures for therapeutic purpose is rapidly growing, following the results obtained in vivo in animal models and in the clinical trials. Unfortunately, the potential therapeutic efficacy is not completely exploited, yet. This is mainly due to the fast clearance of the nanostructures in the body. Nanoparticles and the liver have a unique interaction because the liver represents one of the major barriers for drug delivery. This interaction becomes even more relevant and complex when the drug delivery strategies employing nanostructures are proposed for the therapy of liver diseases, such as hepatocellular carcinoma (HCC). In this case, the selective delivery of therapeutic nanoparticles to the tumor microenvironment collides with the tendency of nanostructures to be quickly eliminated by the organ. The design of a new therapeutic approach based on nanoparticles to treat HCC has to particularly take into consideration passive and active mechanisms to avoid or delay liver elimination and to specifically address cancer cells or the cancer microenvironment. This review will analyze the different aspects concerning the dual role of the liver, both as an organ carrying out a clearance activity for the nanostructures and as target for therapeutic strategies for HCC treatment.

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.

Synthesis, characterization, and in vitro evaluation of curcumin-loaded albumin nanoparticles surface-functionalized with glycyrrhetinic acid

We have designed and developed curcumin (Ccn)-loaded albumin nanoparticles (BNPs) surface-functionalized with glycyrrhetinic acid (Ccn-BNP-GA) for GA receptor-mediated targeting. Ccn-BNP-GA was prepared by conjugating GA as a hepatoma cell-specific binding molecule onto the surface of BNPs. Ccn-BNP-GA showed a narrow distribution with an average size of 258.8±6.4 nm, a regularly spherical shape, an entrapment efficiency of 88.55%±5.54%, and drug loading of 25.30%±1.58%. The density of GA as the ligand conjugated to BNPs was 140.48±2.784 μg/g bovine serum albumin. Cytotoxicity assay results indicated that Ccn-BNP-GA was significantly more cytotoxic to HepG2 cells and in a concentration-dependent manner. Ccn-BNP-GA also appeared to be taken up to a greater extent by HepG2 cells than undecorated groups, which might be due to the high affinity of GA for GA receptors on the HepG2 cell surface. These cytotoxicity assay results were corroborated by analysis of cell apoptosis and the cell cycle. Further, Ccn-BNP-GA showed an approximately twofold higher rate of cell apoptosis than the other groups. Moreover, proliferation of HepG2 cells was arrested in G₂/M phase based on cell cycle analysis. These results, which were supported by the GA receptor-mediated endocytosis mechanism, indicate that BNPs surface-functionalized with GA could be used in targeted cancer treatment with high efficacy, sufficient targeting, and reduced toxicity.

A novel glycyrrhetinic acid-modified oxaliplatin liposome for liver-targeting and in vitro/vivo evaluation

In this study, oxaliplatin (OX) liposomes surface-modified with glycyrrhetinic acid (GA) were developed by the film-dispersion method. Their morphology, physical and chemical properties, and in vitro release performance were investigated. The transmission electron microscope (TEM) image showed that most liposomes were spherical particles with similar size and uniform dispersion. Both OX-liposomes and GA-OX-liposomes had an average size of 90 nm. They were negatively charged, with zeta potentials of −20.6 and −21.3 mV, respectively, and the entrapment efficiency values of both were higher than 94%. In vitro data showed that the application of liposomes could prolong the OX release. The relatively high correlation coefficient values obtained from analyzing the amount of drug released versus the square root of time depicted that release followed the Weibull model. No significant changes were observed after the addition of GA to the liposomes. In vivo, the relatively long time to reach the maximum plasma concentration of OX-liposomes suggested a sustained-release profile of liposomes, which was consistent with the results of the in vitro release study. The increased area under the curve and maximum plasma concentration of OX-liposomes and GA-OX-liposomes demonstrated an increased absorption. The drug concentration in tissues indicated that the GA-modified liposomes delivered OX mainly to liver after intravenous administration. In addition, no severe signs, such as appearance of epithelial necrosis or sloughing of epithelial cells, were detected in histology studies.

Poly(butylcyanoacrylate) and Poly(ε-caprolactone) Nanoparticles Loaded with 5-Fluorouracil Increase the Cytotoxic Effect of the Drug in Experimental Colon Cancer

The clinical use of 5-fluorouracil, one of the drugs of choice in colon cancer therapy, is limited by a nonuniform oral absorption, a short plasma half-life, and by the development of drug resistances by malignant cells. We hypothesized that the formulation of biodegradable nanocarriers for the efficient delivery of this antitumor drug may improve its therapeutic effect against advanced or recurrent colon cancer. Hence, we have engineered two 5-fluorouracil-loaded nanoparticulate systems based on the biodegradable polymers poly(butylcyanoacrylate) and poly(ε-caprolactone). Drug incorporation to the nanosystems was accomplished by entrapment (encapsulation/dispersion) within the polymeric network during nanoparticle synthesis, i.e., by anionic polymerization of the monomer and interfacial polymer disposition, respectively. Main factors determining 5-fluorouracil incorporation within the polymeric nanomatrices were investigated. These nanocarriers were characterized by high drug entrapment efficiencies and sustained drug-release profiles. In vitro studies using human and murine colon cancer cell lines demonstrated that both types of nanocarriers significantly increased the antiproliferative effect of the encapsulated drug. In addition, both nanoformulations produced in vivo an intense tumor growth inhibition and increased the mice survival rate, being the greater tumor volume reduction obtained when using the poly(ε-caprolactone)-based formulation. These results suggest that these nanocarriers may improve the antitumor activity of 5-fluorouracil and could be used against advanced or recurrent colon cancer.