Antitumor activities of novel glycyrrhetinic acid-modified curcumin-loaded cationic liposomes in vitro and in H22 tumor-bearing mice

Abstract

At present, the chemotherapy of advanced inoperable liver cancer is limited with serious side effects. Curcumin possesses multiple cancer preventive activities and low safety concerns. However, its poor solubility and instability in water pose significant pharmacological barriers to its clinical application. In this study, we presented a novel delivery system - the glycyrrhetinic acid modified curcumin-loaded cationic liposomes (GAMCLCL) and investigated its antitumor activities on HepG2 cells in vitro and in H22 tumor-bearing mice. The experimental results demonstrated that GAMCLCL was a cationic liposome and could be Intravenous administration. Compared to free curcumin, GAMCLCL exhibited stronger antitumor activities in vitro and in vivo. The antitumor results of GAMCLCL after intravenous administration were very similar to those after intratumoral administration. The main activities of GAMCLCL and curcumin included inhibition of HepG2 cell proliferation, inhibition of tumor growth, reduction of tumor microvascular density, down-regulation of the expression of VEGF protein, and up-regulation of the expression of Caspases3 protein in H22 tumor tissues. Furthermore, GAMCLCL improved the parameters of WBC, RBC, ALT, CRE, LDH of H22 tumor-bearing mice. Curcumin is a nontoxic natural compound with definite antitumor activities, its antitumor effects can be enhanced by preparation of GAMCLCL.

Keywords: Curcumin; H22 hepatoma transplanted tumor; antitumor effects; glycyrrhetinic acid; glycyrrhetinic acid modified curcumin-loaded cationic liposomes.

Figure 1.

The physical characteristics of GAMCLCL. A: the morphology of GAMCLCL; B: the particle size of GAMCLCL; C: the potential of GAMCLCL.

Figure 2.

The safety results of GAMCLCL. A: Photograph of sample hemolysis test. Tube 1-5 are sample tube, their concentrations from high to low; tube 6 is negative tube; tube 7 is positive tube. B: the bar graph for hemolysis rate of GAMCLCL from tube 1 to 5. C: photograph of rabbit ear-rim vein slice of HE staining (100X). (The scale bar = 100 um).

Figure 3.

The results of cellular test in vitro. A: the line chart of cellular uptake by flow cytometry in 1, 2, 4 hours, respectively. Compared to free curcumin, *p < .01. B: the bar graph of cellular apoptosis rate by flow cytometry. Compared to two blank groups, *p < .01; compared to curcumin group, ★p < .01. C: the line chart of cytotoxicity at different concentrations within 24 hours. D: the line chart of cytotoxicity at different concentrations in 48 hours.

Figure 4.

Bar graph of biochemical parameters (WRC, RBC, MCH, CRE, ALT, LDH). Compared to the normal group, ▲p < .05, *p < .01. Compared to the mode group, △p < .05, ★p < .01.

Figure 5.

The results of MVD, VEGF, caspase3 in vivo. 1: the immunohistochemical pictures of MVD, the scale bar = 20 μm. 2: the bar graph of MVD of different groups, compared to mode group, *p < .01. 3 and 5 are the electrophoresis picture of VEGF and caspase3, respectively. 4 and 6 are bar graph of VEGF and caspase3, respectively. The β-actin is as internal standard, compared to mode group, △p < .05, *p < .01. A: mode group; B: adriamycin group; C: high dose of GAMCLCL group; D: middle dose of GAMCLCL group; E: Low dose of GAMCLCL group; F: curcumin group.