In vitro and in vivo evaluation of N,N,N-trimethylphytosphingosine-iodide (TMP) in liposomes for the treatment of angiogenesis and metastasis.
ABSTRACT Phytosphingosine and methyl derivatives are important mediators on cellular processes, and are associated with cell growth and death. The antitumor activity of N,N,N-trimethylphytosphingosine-iodide (TMP) as a novel potent inhibitor of angiogenesis and metastasis was evaluated in B16F10 murine melanoma cells. The results indicated that TMP itself effectively inhibited in vitro cell migration, tube formation, and the expression of angiogenic factors as well as in vivo lung metastasis. However, TMP slightly suppressed in vivo experimental tumor metastasis in its free form and induced side effects including hemolysis and local side effects. Therefore, in an attempt to reduce the toxicity and the undesirable side effects of TMP, a liposomal formulation was prepared and tested for its effectiveness. TMP liposomes retained the effectiveness of TMP in vitro while side effects were reduced, and both in vivo experimental and spontaneous tumor metastasis were significantly suppressed. These results support the conclusion that TMP effectively inhibits in vitro angiogenesis as well as in vivo metastasis, and a liposomal formulation is more efficient delivery system for TMP treatment than solution.