Targeting of soybean-derived sterylglucoside liposomes to liver tumors in rat and mouse models

Evaluation system construction and factor impact analysis of silica-gel adsorption to extract phytosterol glycosides from soybean lecithin powder

BACKGROUND

Soybean lecithin powders are good sources of phytosterol glucosides (PGs) containing acyl-sterylglycosides (ASGs) and sterylglucosides (SGs), but PG extraction from soybean lecithin powder is difficult due to the solubilizing property of phospolipids. To comprehensively utilize soybean lecithin resources, an evaluation system construction and factor impact analysis of PG extraction by silica-gel adsorption was investigated in this article.

RESULTS

With high-performance liquid chromatography (HPLC) as the main experimental analysis method, software such as SIMICA and SPSS were applied to construct an evaluation system of PG extraction. Different from scores plot in SIMICA for distinguishing samples in chloroform from others, the loading plot and binary variant correlation analysis of all indicators in PG extraction were brought to confirm four evaluation indicators containing PG purity, ASG recovery, SG recovery and phospholipid recovery. In the factor impact analysis, four times elution from silica-gel sediment was enough to achieve a PG product with least reagent waste, while SPW in petroleum ether at 50 mg mL-1 with 1:3 silica-gel dosage (lecithin/silica-gel, w/w) was then determined as the optimum of single factors.

CONCLUSION

All studies in this article were of great significance, as they laid foundations for research of PG extraction procedure, as well as PG industrial production, facilitating the comprehensive utilization of lecithin resources. © 2019 Society of Chemical Industry.

NF-κB increased expression of 17β-hydroxysteroid dehydrogenase 4 promotes HepG2 proliferation via inactivating estradiol

Hepatocellular carcinoma (HCC) arises in a setting of chronic inflammation induced by inflammatory cytokines, such as nuclear factor-kappaB (NF-κB). HCC is a male-predominant cancer that can be attenuated by estradiol (E2) in vitro and in vivo. Although 17β-hydroxysteroid dehydrogenase 4 (HSD17B4) has been implicated as an estradiol-inactivating enzyme, and its promoter sequence contains two putative NF-κB elements: it is currently unknown whether HSD17B4 is the link between inflammation, estradiol and proliferation in hepatoma cells. In this study, HepG2 cells were used to investigate the role of HSD17B4 in the proliferation of liver cancer cells treated with the NF-κB activator, tumor necrosis factor-alpha (TNF-α), with the inhibitor of NF-κB activation, pyrrolidinedithiocarbamate (PDTC), or with a related specific siRNA. We demonstrated that the human HSD17B4 gene is a target for NF-κB activation in inflammation-stimulated HepG2 cells. HSD17B4 is up-regulated via the binding of activated NF-κB to the distal NF-κB-responsive element via TNF-α stimulation, which then promotes cell proliferation by decreasing the levels of E2 and enhancing the expression of interleukin 6 (IL-6), cyclin D1 and proliferating cell nuclear antigen (PCAN). These results from HepG2 cells are consistent with the observation that HSD17B4 is highly expressed and activated NF-κB is highly co-localized with the NF-κB-responsive element of HSD17B4 in liver tumor tissues from HCC patients. Our findings indicate for the first time that HSD17B4 plays an important role in aggravated HCC progression and provides a novel therapeutic target for HCC.

Comparing different sterol containing solid lipid nanoparticles for targeted delivery of quercetin in hepatocellular carcinoma

Quercetin (QT) is a potential chemotherapeutic drug with low solubility that seriously limits its clinical use. The aim of this study was enhancing cellular penetration of QT by sterol containing solid lipid nanoparticles (SLNs) which make bilayers fluent for targeting hepatocellular carcinoma cells. Three variables including sterol type (cholesterol, stigmasterol and stigmastanol), drug and sterol content were studied in a surface response D-optimal design for preparation of QT-SLNs by emulsification solvent evaporation method. The studied responses included particle size, zeta potential, drug loading capacity and 24 h release efficiency (RE24%). Scanning electron and atomic force microscopy were used to study the morphology of QT-SLNs and their thermal behavior was studied by DSC analysis. Cytotoxicity of QT-SLNs was determined by MTT assay on HepG-2 cells and cellular uptake by fluorescence microscopy method. Optimized QT-SLNs obtained from cholesterol and QT with the ratio of 2:1 that showed particle size of 78.0 ± 7.0 nm, zeta potential of -22.7 ± 1.3 mV, drug loading efficiency of 99.9 ± 0.5% and RE24 of 56.3 ± 3.4%. IC50 of QT in cholesterol SLNs was about six and two times less than free QT and phytosterol SLNs, respectively, and caused more accumulation of QT in HepG2 cells. Blank phytosterol SLNs were toxic on cells.

Silymarin loaded liposomes for hepatic targeting: in vitro evaluation and HepG2 drug uptake

Silymarin has hepatoprotective properties and is used in treatment of various liver diseases, but its bioavailability from oral products is very poor. In order to overcome its poor oral bioavailability we have prepared silymarin loaded hepatic targeting liposomes suitable for parenteral administration. The liposomal formulations were composed of hydrogenated soy phosphatidylcholine and cholesterol with or without distearoylphosphoethanolamine-(polyethyleneglycol)-2000 and various amounts of β-sitosterol β-D-glucoside (Sito-G) as the hepatic targeting moiety. Increasing the amount of Sito-G in the liposomes gradually decreased drug encapsulation efficiencies from ∼70% to ∼60%; still showing promising drug encapsulation efficiencies. Addition of Sito-G to non-PEGylated liposomes clearly affected their drug release profiles and plasma protein interactions, whereas no effect on these was seen for the PEGylated liposomes. Non-PEGylated liposomes with 0.17 M ratio of Sito-G exhibited the highest cellular drug uptake of 37.5% for all of the studied liposome formulations. The highest cellular drug uptake in the case of PEGylated liposomes was 18%, which was achieved with 0.17 and 0.33 M ratio of added Sito-G. The liposome formulations with the highest drug delivery efficacy in this study showed hemolytic activities around 12.7% and were stable for at least 2 months upon storage in 20 mM HEPES buffer (pH 7.4) containing 1.5% Polysorbate 80 at 4 °C and room temperature. These results suggest that the Sito-G containing liposomes prepared in this work have hepatic targeting capability and that they are promising candidates for delivering silymarin to the liver.

Evaluation of pullulan-functionalized doxorubicin nanoparticles for asialoglycoprotein receptor-mediated uptake in Hep G2 cell line

The present study discusses evaluation of pullulan-functionalized doxorubicin nanoparticles for asialoglycoprotein receptor-mediated uptake in the Hep G2 cell line. Doxorubicin hydrochloride (DOX) nanoparticles using polymers of different hydrophobic character, polyethylene sebacate (hydrophobic) and poly (lactic-co-glycolic acid) (intermediate hydrophobicity) with high entrapment efficiency and particle size were prepared by modified nanoprecipitation, using Gantrez AN 119 as complexing agent. Nanoparticles of Gantrez AN 119 were also prepared to represent a hydrophilic polymer. Cell uptake of DOX nanoparticles was found to be comparable to DOX solution irrespective of DOX concentration, nanoparticles size, and pullulan concentration. Furthermore, uptake of nanoparticles functionalized with or without pullulan prepared with polymers of different hydrophobic character revealed comparable uptake. Comparable uptake of DOX solution and DOX nanoparticles functionalized with or without pullulan suggest extracellular release of DOX as the mechanism of uptake from the nanoparticles. In vivo evaluation in hepatic cancer model is therefore essential to confirm the role of pullulan as asialoglycoprotein receptors ligand.

Retinoids: new use by innovative drug-delivery systems

BACKGROUND

Retinoids represent an old class of bioactives used in the treatment of different skin pathologies (such as acne and psoriasis) and in the treatment of many tumors. Unfortunately, they present several side effects, i.e., burning of skin and general malaise after systemic administration and they are very unstable after exposition to light.

METHODS

One of the most promising new approaches for reducing the side effects of retinoids while improving their pharmacological effect is the use of drug-delivery devices. This review explains the current status of retinoid drug transport, which has been developing over the last few years, explaining the modification of their biopharmaceutical properties in detail after encapsulation/inclusion in vesicular and polymeric systems.

RESULTS/CONCLUSION

Different colloidal and micellar systems containing retinoid drugs have been realized furnishing important potential advancements in traditional therapy.

Mechanisms of co-modified liver-targeting liposomes as gene delivery carriers based on cellular uptake and antigens inhibition effect

In order to deliver antisense oligonucleotides (asODN) into hepatocytes orientedly in the treatment of hepatitis B virus (HBV) infection, the liver-targeting cationic liposomes was developed as a gene carrier, which was co-modified with the ligand of the asialoglycoprotein receptor (ASGPR), beta-sitosterol-beta-d-glucoside (sito-G) and the nonionic surfactant, Brij 35. Flow cytometry (FCM) analysis and enzyme-linked immunosorbent assay (ELISA) showed that the asODN-encapsulating cationic liposomes exhibited high transfection efficiency and strong antigens inhibition effect in primary rat hepatocytes and HepG2.2.15 cells, respectively. With the help of several inhibitors acting on different steps during the targeting lipofection, the cellular uptake mechanisms of the co-modified liver-targeting cationic liposomes were investigated through antigens inhibition effect assay and confocal laser scanning microscopy (CLSM) analysis. The cellular uptake with high transfection efficiency seemed to involve both endocytosis and membrane fusion. The ligand sito-G was confirmed to be able to enhance ASGPR-mediated endocytosis, the nonionic surfactant Brij 35 seemed to be able to facilitate membrane fusion, and the co-modification resulted in the most efficient transfection but no enhanced cytotoxicity. These results suggested that the co-modified liver-targeting cationic liposomes would be a specific and effective carrier to transfer asODN into hepatocytes infected with HBV orientedly.

Synthesis of phospholipid-conjugated bile salts and interaction of bile salt-coated liposomes with cultured hepatocytes

To examine the possibility of targeting liposomes to hepatocytes via bile salts, the bile salt lithocholyltaurine was covalently linked to a phospholipid. The isomeric compounds disodium 3alpha-(2-(1,2-O-distearoyl-sn-glycero-3-phospho-2'-ethanolamidosuccinyloxy)ethoxy)-5beta-cholan-24-oyl-2'-aminoethansulfonate and disodium 3beta-(2-(1,2-O-distearoyl-sn-glycero-3-phospho-2'-ethanolamidosuccinyloxy)ethoxy-5beta-cholan-24-oyl-2'-aminoethansulfonate (DSPE-3beta-LCT) were synthesized and incorporated into liposomal membranes. Confocal laser scanning microscopy studies showed that bile salt-bearing liposomes (BSLs) attach to the surface of rat hepatocytes in culture. Studies with radioactively labeled liposomes revealed that the bile salt linked via the 3beta-conformation resulted in a higher attachment efficiency than that with the 3alpha-derivative. In the presence of BSLs corresponding to 2 mM liposomal phosphatidylcholine, uptake of 50 microM cholyltaurine (CT) into hepatocytes was reduced by approximately 40% by the 3beta-derivative and by approximately 17% by the 3alpha-derivative. When added simultaneously with the liposomes, CT up to 75 microM inhibited the binding of DSPE-3beta-LCT-bearing liposomes. By contrast, increasing concentrations reversed this inhibition and resulted in an increased bile salt-mediated binding. The same was true when CT was added 10 min before the liposomes were added. The attachment of BSLs to the surface of hepatocytes opens up promising possibilities for hepatocyte-specific drug delivery. More generally, not only substrates for cellular endocytosing receptors but also substrates for cellular carrier proteins should be suitable ligands for the cell-specific targeting of nanoscale particles such as liposomes.

Hepatocytes targeting of cationic liposomes modified with soybean sterylglucoside and polyethylene glycol

AIM

In this study, a hepatocyte-specific targeting technology was developed by modifying cationic liposomes with soybean sterylglucoside (SG) and polyethylene glycol (PEG) (C/SG/PEG-liposomes).

METHODS

The liposomal transfection efficiencies in HepG(2) 2.2.15 cells were estimated with the use of fluorescein sodium (FS) as a model drug, by flow cytometry. The antisense activity of C/SG/PEG-liposomes entrapped antisense oligonucleotides (ODN) was determined as HBsAg and HBeAg in HepG(2) 2.2.15 cells by ELISA. The liposome uptake by liver and liver cells in mice was carried out after intravenous injection of (3)H-labeled liposomes.

RESULTS

C/SG-liposomes entrapped FS were effectively transfected into HepG(2) 2.2.15 cells in vitro. C/SG/PEG-liposomes entrapped ODN, reduced the secretion of both HBsAg and HBeAg in HepG(2) 2.2.15 cells when compared to free ODN. After in vivo injection of (3)H-labeled C/SG/PEG-liposomes, higher radiation accumulation was observed in the hepatocytes than non-parenchymal cells of the liver.

CONCLUSION

C/SG/PEG-liposomes mediated gene transfer to the liver is an effective gene-delivery method for hepatocytes-specific targeting, which appears to have a potential for gene therapy of HBV infections.

Intravenous liposomal benznidazole as trypanocidal agent: increasing drug delivery to liver is not enough

With the aim of investigating if delivery of benznidazole (BNZ) to liver could be increased by incorporating the drug in multilamellar liposomes, single bolus of free BNZ or liposomal BNZ formulations (MLV-BNZ) composed of HSPC:DSPG:Chol 2:1:2 (mol/mol/mol) at 0.7% (w/w) drug/total lipid ratio, were injected by intramuscular (i.m.), subcutaneous (s.c.) and intravenous (i.v.) routes, at 0.2 mg BNZ/kg, in rats. The resulting blood concentrations were followed along 9 h post-injection (p.i.) and drug accumulation in liver was determined after 4 and 9 h p.i. Only upon i.v. injection of MLV-BNZ, a threefold higher BNZ accumulation in liver was obtained, together with blood BNZ concentrations of 1.1 microg/ml (30% lower than the blood BNZ concentration achieved upon i.v. administration of free drug) occurred 4 h p.i. However, such increased liver uptake of BNZ, raised twice a week had no effect on parasitaemia levels of mice infected with the RA strain of Trypanosoma cruzi. Our results indicate that the relationship between increased selectivity for an infected tissue and therapeutic effect is not always straightforward, at least for the MLV-BNZ regimen used in the present study.

Effects on M5076-hepatic metastasis of retinoic acid and N-(4-hydroxyphenyl) retinamide, fenretinide entrapped in SG-liposomes

Retinoic acid (RA), a potent inducer of cell differentiation, and N-(4-hydroxyphenyl)retinamide (4-HPR, fenretinide), a potent inducer of apoptosis, are well known as anticancer agents that are administered orally to patients for leukemia, breast and prostate cancer, respectively. However, it has not been studied whether both retinoids are effective on metastatic cancer. In mice implanted with M5076 cells, murine reticulum cell sarcoma survival times were prolonged by i.v. treatment of RA and 4-HPR entrapped in liposomes containing soybean-derived sterylglucoside mixture (SG), which accumulates in liver. In contrast, free RA and 4-HPR were inactive. These results indicate that RA and 4-HPR in SG-liposomes exhibit anticancer efficacy on metastatic cancers, and may have great potential for clinical use in the treatment of various cancers.

[Induction of cell differentiation and development of new anticancer drugs]

Cell differentiation is essential for normal growth and homeostasis, and drug-induced differentiation of tumor cells into benign or normal cells is an important approach for anticancer chemotherapy. Studies of induction mechanisms for cell differentiation and discovery of differentiation-inducing factors are thus critical components of drug development. The Screening of differentiation-inducing factors, such as purified aldehyde reductase, a xenobiotic metabolite enzyme, that induces differentiation of human acute myeloid leukemia HL60 cells into monocyte/macrophage cells is described. Mechanisms of all-trans-retinoic acid (RA)-induced differentiation are also covered. RA is a potent inducer of HL60 cell differentiation and when used as a sole agent it can induce complete remission in patients with acute promyelocytic leukemia (APL). While one mechanism of the effect of RA involves RA nuclear receptors, retinoylation (a posttranslational modification of proteins by RA) may be a new nongenomic mechanism by which RA acts on cells. An early event in RA-induced differentiation may be retinoylation of RII alpha (regulatory subunits of cAMP-dependent protein kinase), in which RII alpha units are retinoylated and the retinoylated RII alpha is then translocated to the nucleus. Drugs can also be combined with RA in RA-differentiation therapy. Cytodifferation therapy by RA in APL patients exhibits limitations due to the resistance of relapsed patients to further RA treatment. This may occur through the induction of expression of various genes that reduce RA blood concentrations. Treatment with combinations of RA and other agents may be one way to reduce induction of those genes. Good candidates for such agents include cAMP-elevating agents, retinoids, steroids, and fatty acids that synergistically induce differentiation of HL60 cells. Two derivatives of falconensone A, falconensone A p-bromophenylhydrazone, which has a bromophenyl residue, and falconensone A dioxime, which possesses a hydroxy residue, were synthesized to incorporate features of RA and N-[4-hydroxyphenyl] retinamide. Both derivatives have exhibited more potent biological activity than the parent falconensone A in vitro and in vivo.

Efficacy of lactosaminated and intact N-succinylchitosan-mitomycin C conjugates against M5076 liver metastatic cancer

In this study,lactosaminated N-succinyl-chitosan (Lac-Suc) was investigated for its liver targeting ability in the early metastatic stage of liver cancer, and subsequently Lac-Suc-mitomycin C conjugate (Lac-Suc-MMC) and highly-succinylated N-succinyl-chitosan (Suc(II))-MMC conjugate (Suc(II)-MMC) were examined for efficacy against the liver metastasis. Mice into which M5076 cells were inoculated intravenously were used as liver metastatic models. Fluorescently labelled Lac-Suc (Lac-Suc-FTC) was intravenously administered at a daily dose of 0.2 mg/mouse for 4 days or at a single dose of 0.8 mg/mouse at 3 days post-inoculation. At a dose of 0.2 mg/mouse for 4 days, liver accumulation of Lac-Suc-FTC was increased after all except the fourth injection, indicating that the capacity of accumulation might be limited to around 110 microg per mouse with repeated daily administration at 0.2 mg/mouse. As to the efficacy of intravenous administration at 7 days post-inoculation, Lac-Suc-MMC was less effective at a dose of 1 mg kg(-1) for 4 days than a single dose of 4 mg kg(-1). This result was not in accordance with that expected from the biodistribution study. On the other hand, with intravenous administration at 3 days post-inoculation, Suc(II)-MMC was more effective on repeated administration, and it showed higher efficacy than Lac-Suc-MMC at both 1 mg kg(-1) for 4 days and 4 mg kg(-1) as a single dose. Further, with intravenous administration at 3 days post-inoculation, Suc(II)-MMC exhibited a much higher survival effect at a dose of 4 mg kg(-1) for 4 days.

Efficiency of liposomes surface-modified with soybean-derived sterylglucoside as a liver targeting carrier in HepG2 cells

We investigated the interaction of liposomes surface-modified with soybean-derived sterylglucoside (SG) (SG-liposomes) with HepG2 cells in the point of involvement of asialoglycoprotein receptor (ASGP-R) mediated endocytosis and examined the efficiency of SG-liposomes as drug carriers using 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) as a maker of liposome, carboxylated polystyrene microspheres (Fluoresbrite) as a model drug not taken up in cells and doxorubicin (DXR). SG-liposomes were composed of dipalmitoylphosphatidylcholine (DPPC), cholesterol (Ch) and SG (DPPC/Ch/SG=6:3:1, molar ratio) and DiI, Fluoresbrite and DXR were entrapped in SG-liposomes, respectively. Each SG-liposome was incubated with HepG2 cells at 4 or 37 degrees C, and co-incubated with asialofetuin (AF) as a competitor of ASGP-R. The association of DiI, Fluoresbrite or DXR entrapped in SG-liposomes with HepG2 cells at 37 degrees C was significantly higher than that in liposomes containing no SG. That of DiI and Fluoresbrite was reduced significantly by the incubation with AF, but that of DXR was not affected. These findings suggest that Fluoresbrite behaves like the lipid component of SG-liposomes, but DXR in SG-liposomes does not behave similar to the lipid component of SG-liposomes, thus, its drug behavior released from liposomes may be due to its physicochemical properties. SG-liposomes are potentially useful drug carriers to the liver, because the glucose residue may work as a kind of ligand for ASGP-R.

Liver-targeted gene transfer into a human hepatoblastoma cell line and in vivo by sterylglucoside-containing cationic liposomes

We investigated the transfection efficiency of beta-sitosterol beta-D-glucoside (Sit-G)-containing liposome/DNA complex (Sit-G-liposome/DNA complex) for liver targeting. The Sit-G-liposome/DNA complex was composed of Tfx-20 reagent (Tfx), ie synthetic cationic lipid [N,N,N',N'-tetramethyl-N,N'-bis(2-hydroxyethyl)-2,3-di(oleoyloxy)-1,4-butanediammonium iodide] with L-dioleoylphosphatidylethanolamine (DOPE), 3 beta[N-(N',N'-dimethylaminoethane)-carbamoyl]cholesterol (DC-Chol) and Sit-G with plasmid DNA. The in vitro studies were performed in HepG2 cells in serum-containing medium and the in vivo studies were carried out in the mice following intravenous injection. The Sit-G-liposome produced a Sit-G-liposome/DNA complex of relatively small size (100--250 nm). Transfection efficiency of the luciferase marker gene by Sit-G-liposome/DNA complex was increased in the presence of 10% serum in vitro, and was selectively high in the mouse liver reaching expression values up to an average of 14.9 pg luciferase/mg tissue protein, compared with Tfx/DNA complex, which showed approximately three-fold higher gene expression than Sit-G-liposome/DNA complex in vitro. High in vitro transfection efficiency by Sit-G-liposome/DNA complex seemed to be possible even with large lipid precipitates, whereas high in vivo activity seemed to be related to small and dispersed complexes. The interaction of liposome/DNA complexes with serum may be a key point to predict the in vivo efficiency of a liposome vector.