Effects of MtFt overexpression on in vitro–cultured xenograft-derived tumor cell growth and apoptosis of tumor xenografts. (A) MtFt expression decreased in vitro growth of xenograft-derived tumor cells (“Materials and methods”). (B) MtFt expression did not lead to cleavage of PARP in H1299 cell– and B9 cell–derived tumor xenografts. Tumor lysates (prepared as in Figure 3A; see “Materials and methods”) were used to measure PARP protein levels by Western blotting. Representative of 3 independent experiments that produced similar results (mean of triplicate ± SD); *P < .01.