Abstract 370: In vitro and in vivo antitumor studies of a lipophilic curcumin derivative loaded lipid-based nanoemulsion

Abstract

Abstract Introduction and Objective: 1,5-diarylpenta-1,4-dien-3-one and derivatives as 1,5-bis(4-hydroxy-3-methoxyphenyl)-penta-1,4-dien-3-one (1) are phenolic compounds with structure similar to curcumin, a natural substance with a large variety of biological effects. Compound 1 showed a good antitumor activity and a low toxicity in in vivo studies, but it is not water-soluble. Here we developed a formulation for intravenous injection based on emulsion for a lipophilic diacyl derivative of compound 1, the 1,5-bis(4-oleyl-3-methoxyphenyl)-penta-1,4-dien-3-one (2) and evaluated its cytotoxicity against B16F10 murine melanoma cells, toxicity and tumor regression in B16F10 melanoma-bearing mice. Materials and Methods: Compound 1 was synthesized through the reaction between vanillin and acetone under acid catalysis. After purification 1 was converted in 2 by the reaction with oleic acid using DCC and DMAP in CHCl2. A mixture of 2, cottonseed oil, phosphatidylcholine, β-carotene, cholesterol and Tween 20 were emulsified by high-pressure homogenization to obtain compound 2-loaded lipid nanoemulsion. The formulation, as well as free compound 2 and controls (1 and nanoemulsion) were assayed against murine melanoma (B16F10), using MTT method. For animal toxicity we followed the OECD protocol, starting in 300mg/Kg dose injected in bolus by intraperitoneal via in BALB/c mice. Body weight, hematological, biochemical e histophatological analysis were performed to analyze toxicity. Tumor regression was evaluated in six group of B16F10 tumor-bearing mice intraperitonially injected with five doses of 2-loaded lipid nanoemulsion at 5, 10 and 20mg/kg, 5 mg/kg of 1, lipid nanoemulsion and saline, at day 7th to day 15st after tumor inoculation. Results: The yield of both reactions was high; the efficiency of incorporation of 2 into lipid nanoemulsion was 100% and the particle size 95 nm, stable for at least four months. The cytotoxicity of free as well 2-loaded lipid nanoemulsion was lower than 1. Toxicity studies for 2-loaded lipid nanoemulsion at 300mg/kg dose showed no significant weight loss, minimal biochemical and hematological alterations when compared with control groups. Histophatological analysis showed no significant alterations in organs morphology, as necrosis, fibrosis, or leucocitary infiltration of pre-clinical interest, except a little concentration of leukocytes in the myocardium. Tumor regression and survival of mice injected with 20mg/kg 2-loaded lipid nanoemulsion was similar to those that received 5mg/kg of 1, on the other hand the number of metastasis was lower. Conclusion: The conversion of compound 1 in its lipophilic derivative 2 has the great advantage of avoiding toxic organic solvents and decrease in vivo toxicity, despite of reducing the cytotoxicity as well as antitumor activity around four-fold, but mice treated with 20mg/kg dose showed the lowest number of metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 370. doi:10.1158/1538-7445.AM2011-370