Liposomal curcumin with and without oxaliplatin: effects on cell growth, apoptosis, and angiogenesis in colorectal cancer.

The role of curcumin (diferuloylmethane), a proapoptotic compound, for the treatment of cancer has been an area of growing interest. Curcumin in its free form is poorly absorbed in the gastrointestinal tract and therefore may be limited in its clinical efficacy. Liposome encapsulation of this compound would allow systemic administration. The current study evaluated the preclinical antitumor activity of liposomal curcumin in colorectal cancer. We also compared the efficacy of liposomal curcumin with oxaliplatin, a standard chemotherapy for this malignancy. In vitro treatment with liposomal curcumin induced a dose-dependent growth inhibition [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt] and apoptosis [poly(ADP-ribose) polymerase] in the two human colorectal cancer cell lines tested (LoVo and Colo205 cells). There was also synergism between liposomal curcumin and oxaliplatin at a ratio of 4:1 in LoVo cells in vitro. In vivo, significant tumor growth inhibition was observed in Colo205 and LoVo xenografts, and the growth inhibition by liposomal curcumin was greater than that for oxaliplatin (P < 0.05) in Colo205 cells. Tumors from animals treated with liposomal curcumin showed an antiangiogenic effect, including attenuation of CD31 (an endothelial marker), vascular endothelial growth factor, and interleukin-8 expression by immunohistochemistry. This study establishes the comparable or greater growth-inhibitory and apoptotic effects of liposomal curcumin with oxaliplatin both in vitro and in vivo in colorectal cancer. We are currently developing liposomal curcumin for introduction into the clinical setting.