017). Whereas H295 xenografts treated with NVP-AEW541 were similar in histological appearance to those treated with IMC-A12 and exhibited a 34% reduction in tumor burden over controls, this decrease fell short of being statistically significant (P = 0.086) (supplementary Fig. 2, published glucose metabolism as supplemental data on The Endocrine Society��s Journals Online Web site at http://jcem.endojournals.org). NVP-AEW541 treatment of mice harboring RL251 xenografts also had an insignificant reduction in tumor volume (P = 0.57). NVP-AEW541 was well tolerated in treated mice with no substantial adverse effects or weight changes observed during treatment (data not shown). Figure 5 Targeted inhibition of tumor growth in vivo.

A, H295 (left panel) and RL251 (right panel) cells were injected sc into athymic nude mice and mice were randomized into treatment groups (n = 8 for H295 and n = 10 for RL251). Groups were treated … To determine whether blocking IGF-1R resulted in decreased IGF signaling in vivo, H295 xenografts were subjected to immunoblot analysis (Fig. 5B5B).). Lysates prepared from two separate tumors from control and IMC-A12-treated mice were immunoblotted for Akt and phospho-AktSer473 levels. Although total Akt expression levels were similar in both treatment arms, phospho-AktSer473 levels were decreased in the tumors of mice treated with IMC-A12, thus revealing a targeted decrease in IGF signaling. Taken together, these results indicate in vivo IGF-1R inhibition caused significant and targeted tumor growth delay of human ACC xenografts and underscores the importance of IGF signaling in ACC pathophysiology.

Inhibition of IGF-1R enhances the inhibitory effects of mitotane Mitotane is the standard of care for treatment of ACC because of its specific cytotoxic effects in cortical cells. To evaluate whether this response could be enhanced by additional IGF inhibition, we investigated the effect of combining mitotane with IGF antagonists in culture and in vivo tumor growth. First, MTS proliferation assays were performed Carfilzomib on H295 and RL251 cells with increasing concentrations of NVP-AEW541 and mitotane (Fig. 6A6A).). Whereas both H295 and RL251 cells exhibited a dose-dependent reduction in proliferation when incubated with mitotane (no NVP-AEW541), only H295 cells demonstrated a further decrease in growth when incubated with mitotane and NVP-AEW541. Individually, 30 ��m mitotane and 3 ��m NVP-AEW541 reduced cell viability to 85 and 77% of control levels, respectively. An additive model for the combinatorial effects of the two agents would predict about 65% cell viability compared with untreated cells.