Abstract
Celecoxib, a selective cyclooxygenase-2 inhibitor, has shown potential anticancerous activity against majority of solid tumors especially on patients with colon cancer. However, associations of serious side effects limit the usage of celecoxib in colon cancer treatment. To address this issue and provide an alternative strategy to increase the efficacy of celecoxib, liposomal formulation of celecoxib was prepared and characterized. Anticancer activity of liposomal celecoxib on colon cancer cell HCT 15 was evaluated in vitro. Furthermore, tumor inhibition efficiency by liposomal celecoxib was studied on 7,12-dimethyl benz(a)anthracene (DMBA)-induced tumor in rat model. In order to elucidate the antioxidant activity of celecoxib-loaded liposomes, antioxidant superoxide dismutase (SOD) generation and lipid peroxide (LPx) formation in both liver and kidney tissues were examined. Characterization of the formed unilamellar liposomes revealed the formation of homogeneous suspension of neutral (empty) or anionic (celecoxib-loaded) liposomes with a well-defined spherical shape which have a mean size of 103.5 nm (empty liposome) and 169 nm (liposomal celecoxib). High-performance liquid chromatography (HPLC) analysis and hemolytic assay demonstrated 46% of celecoxib entrapment efficiency and significantly low hemolysis, respectively. Liposomal celecoxib exhibited dose-dependent cytotoxicity and apoptotic activity against HCT 15 cells which are comparable to free celecoxib. In vivo study demonstrated inhibition of tumor growth. Biochemical analysis of the liposomal celecoxib-treated group significantly inhibited the LPx formation (oxygen-free radicals) and increased the activity of SOD. Our results present the potential of inhibiting colon cancer in vitro and DMBA-induced tumor in rat model in vivo by liposomal celecoxib.