A trial to kill tumor cells through Fas (CD95)-mediated apoptosis in vivo.

We tried to induce tumor cell death in vivo through Fas (CD95)-mediated apoptosis. Murine hepatoma MH 134 (Fas-) was transfected with murine Fas antigen cDNA. Fas+ F6b but not Fas- N1d cells underwent apoptosis after treatment with anti-Fas antibody in vitro. The possibility of eradicating tumor cells in vivo with anti-Fas antibody was investigated using double-mutant gld/gld lpr/lpr mice which lack both Fas ligand (FasL) and Fas to avoid cytotoxic activity of the antibody to the liver and interference from endogenous FasL. A single administration of anti-Fas antibody efficiently suppressed the growth of F6b tumors but not that of N1d tumors in these mice. Thus, the therapy with Fas-FasL system may be a promising approach for cancer treatment, and this model is useful for study on in vivo apoptosis-mediated antitumor activity.