ABSTRACT
PURPOSE: Lipid nanoemulsions (LDEs) that bind to low-density lipoprotein (LDL) receptors used as carriers of paclitaxel (PTX) can decrease toxicity and increase PTX antitumoral action. The administration of simvastatin (Simva), which lowers LDL-cholesterol, was tested as an adjuvant to commercial PTX and to PTX associated with LDE (LDE-PTX). MATERIALS AND METHODS: B16F10 melanoma-bearing mice were treated with saline solution or LDE (controls), Simva, PTX, PTX and Simva, LDE-PTX, and LDE-PTX and Simva: PTX dose 17.5 µmol/kg (three intraperitoneal injections, 3 alternate days): Simva 50 mg/kg/day by gavage, 9 consecutive days. RESULTS: Compared with saline controls, 95% tumor-growth inhibition was achieved by LDE-PTX and Simva, 61% by LDE-PTX, 44% by PTX and Simva, and 43% by PTX. Simva alone had no effect. Metastasis developed in only 37% of the LDE-PTX and Simva, 60% in LDE-PTX, and 90% in PTX and Simva groups. Survival rates were higher in LDE-PTX and Simva and in LDE-PTX groups. The LDE-PTX and Simva group presented tumors with reduced cellular density and increased collagen fibers I and III. Tumors from all groups showed reduction in immunohistochemical expression of ICAM, MCP-1, and MMP-9; LDE-PTX and Simva presented the lowest MMP-9 expression. Expression of p21 was increased in the Simva, LDE-PTX, and LDE-PTX and Simva groups. In the Simva and LDE-PTX and Simva groups, expression of cyclin D1, a proliferation and survival promoter of tumor cells, was decreased. Therapy with LDE-PTX and Simva showed negligible toxicity compared with PTX and Simva, which resulted in weight loss and myelosuppression. CONCLUSION: Simva increased the antitumor activity of PTX carried in LDE but not of PTX commercial presentation, possibly because statins increase the expression of LDL receptors that internalize LDE-PTX.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Apoptosis/drug effects , Cell Proliferation/drug effects , Drug Synergism , Lipids/chemistry , Melanoma, Experimental/drug therapy , Animals , Blotting, Western , Cholesterol, LDL/metabolism , Female , Immunoenzyme Techniques , Injections, Intraperitoneal , Melanoma, Experimental/metabolism , Melanoma, Experimental/pathology , Mice , Mice, Inbred C57BL , Paclitaxel/administration & dosage , Receptors, LDL/metabolism , Simvastatin/administration & dosage , Tumor Cells, CulturedABSTRACT
OBJECTIVES: To test the toxicity and antitumoral activity of the compound N-oleyl-daunorubicin (oDNR) with a cholesterol-rich nanoemulsion (LDE) formulation. METHODS: LDE-oDNR was prepared by high-pressure homogenisation of lipid mixtures. B16F10 melanoma cells and NIH/3T3 fibroblasts were used for cytotoxicity tests. The maximum tolerated dose (MTD) of both commercial and LDE-oDNR was determined in mice, and melanoma-bearing mice were used for the antitumoral activity tests. KEY FINDINGS: CC50 for LDE-oDNR and DNR in melanoma cells were 200 µm and 15 µm, respectively, but LDE-oDNR was less toxic against fibroblasts than DNR. MTD for LDE-oDNR was 65-fold higher than commercial DNR. In tumour-bearing mice, LDE-oDNR (7.5 µmol/kg) reduced tumour growth by 59 ± 2%, whereas the reduction by DNR was only 23 ± 2%. LDE-oDNR increased survival rates (P < 0.05), which was not achieved by DNR treatment. The number of mice with metastasis was only 30% in LDE-oDNR-treated mice, compared with 82% under DNR treatment. By flow cytometry, there were 9% viable cells in tumours of animals treated with LDE-oDNR compared with 27% in DNR-treated animals. Less haematological toxicity was observed in LDE-oDNR-treated mice. CONCLUSIONS: Compared with DNR, LDE-oDNR improved tumour growth inhibition and survival rates with pronouncedly less toxicity, and thus may become a new tool for cancer treatment.
Subject(s)
Antibiotics, Antineoplastic/therapeutic use , Cholesterol/chemistry , Daunorubicin/analogs & derivatives , Daunorubicin/therapeutic use , Drug Carriers/chemistry , Melanoma, Experimental/drug therapy , Nanostructures/chemistry , Oleic Acids/therapeutic use , Receptors, LDL/metabolism , Animals , Antibiotics, Antineoplastic/administration & dosage , Antibiotics, Antineoplastic/toxicity , Cell Line, Tumor , Cell Survival/drug effects , Daunorubicin/administration & dosage , Daunorubicin/toxicity , Drug Stability , Emulsions , Male , Melanoma, Experimental/metabolism , Melanoma, Experimental/pathology , Mice, Inbred C57BL , Molecular Structure , Neoplasm Transplantation , Oleic Acids/administration & dosage , Oleic Acids/toxicity , Particle Size , Protein Binding , Toxicity Tests, AcuteABSTRACT
PURPOSE: Use of lipid nanoemulsions as carriers of drugs for therapeutic or diagnostic purposes has been increasingly studied. Here, it was tested whether modifications of core particle constitution could affect the characteristics and biologic properties of lipid nanoemulsions. METHODS: Three nanoemulsions were prepared using cholesteryl oleate, cholesteryl stearate, or cholesteryl linoleate as main core constituents. Particle size, stability, pH, peroxidation of the nanoemulsions, and cell survival and uptake by different cell lines were evaluated. RESULTS: It was shown that cholesteryl stearate nanoemulsions had the greatest particle size and all three nanoemulsions were stable during the 237-day observation period. The pH of the three nanoemulsion preparations tended to decrease over time, but the decrease in pH of cholesteryl stearate was smaller than that of cholesteryl oleate and cholesteryl linoleate. Lipoperoxidation was greater in cholesteryl linoleate than in cholesteryl oleate and cholesteryl stearate. After four hours' incubation of human umbilical vein endothelial cells (HUVEC) with nanoemulsions, peroxidation was minimal in the presence of cholesteryl oleate and more pronounced with cholesteryl linoleate and cholesteryl stearate. In contrast, macrophage incubates showed the highest peroxidation rates with cholesteryl oleate. Cholesteryl linoleate induced the highest cell peroxidation rates, except in macrophages. Uptake of cholesteryl oleate nanoemulsion by HUVEC and fibroblasts was greater than that of cholesteryl linoleate and cholesteryl stearate. Uptake of the three nanoemulsions by monocytes was equal. Uptake of cholesteryl oleate and cholesteryl linoleate by macrophages was negligible, but macrophage uptake of cholesteryl stearate was higher. In H292 tumor cells, cholesteryl oleate showed the highest uptakes. HUVEC showed higher survival rates when incubated with cholesteryl stearate and smaller survival with cholesteryl linoleate. H292 survival was greater with cholesteryl stearate. CONCLUSION: Although all three nanoemulsion types were stable for a long period, considerable differences were observed in size, oxidation status, and cell survival and nanoemulsion uptake in all tested cell lines. Those differences may be helpful in protocol planning and interpretation of data from experiments with lipid nanoemulsions.
Subject(s)
Cholesterol Esters/chemistry , Drug Carriers/chemistry , Nanostructures/chemistry , Biological Transport, Active , Cell Survival , Cells, Cultured , Drug Delivery Systems/methods , Drug Stability , Emulsions/chemistry , Humans , Hydrogen-Ion Concentration , Lipid Peroxidation , Nanomedicine , Particle SizeABSTRACT
Use of lipid nanoemulsions as carriers of drugs for therapeutic or diagnostic purposes has been increasingly studied. Here, it was tested whether modifications of core particle constitution could affect the characteristics and biologic properties of lipid nanoemulsions. Three nanoemulsions were prepared using cholesteryl oleate, cholesteryl stearate, orcholesteryl linoleate as main core constituents. Particle size, stability, pH, peroxidation of the nanoemulsions, and cell survival and uptake by different cell lines were evaluated.It was shown that cholesteryl stearate nanoemulsions had the greatest particlesize and all three nanoemulsions were stable during the 237-day observation period...
