Fig. 3.

Metformin and Salsalate combination mediates increased tumor suppression and inhibition of DNA replication in PrCa xenografts. PC3 xenografts were generated as described in Methods and assigned in groups to receive either vehicle, MET, Salsalate or the Metformin (Met) and Salsalate (Sal) combination without or with RT (single fraction of 10 Gy given 1 week after initiation of drug therapy). Metformin treatment was provided via the drinking water. The concentration was adjusted bi-weekly to achieve delivery of a dose of 250 mg/kg/day and salsalate was incorporated into the chow diet at 2.5 g/kg. Six animals were assigned per group. (A) Tumor growth kinetics: average volume estimates obtained using hand caliper measurements as described in Methods. Mean ± SEM for SAL- and SAL + RT-treated tumors are indicated only at the final evaluation. (B) Representative images of immunohistochemistry analysis of each condition using anti-phosphorylated histone H3 (P-H3) antibody (see Fig. s1 for P-H3 magnified and for negative control images). (C) For each treatment, areas were quantified for% of cells positive the P-H3 (number nuclei stained positive for P-H3 out of 100) and average values (Mean±SE, N = 10) were plotted. NS: non-significant, */#: P < 0.05, **/##: P < 0.01, ***: P < 0.001, ****: P < 0.0001.