Inhibition of epithelial growth factor receptor can play an important role in reducing cell growth and survival in adrenocortical tumors

Medical treatment of adrenocortical carcinoma (ACC) is still far from optimal, since even molecular targeted therapy failed to demonstrate striking results. Clinical trials enrolling ACC patients with high tissue vascular endothelial growth factor receptor (VEGFR) expression levels showed controversial results after treatment with Sunitinib, possibly due to variability in the expression of drug targets, which include epidermal growth factor receptor (EGFR). To better clarify this issue, we evaluated whether VEGFR may play a crucial role in ACC responsiveness to Sunitinib and whether EGFR may represent an alternative target in ACC medical treatment, by employing two ACC cell lines, the NCI-H295 and SW13 cells lines, and adrenocortical tissues primary cultures. Our data show that VEGF/VEGFR system may not be crucial in modulating ACC proliferation and responsiveness to Sunitinib. In addition, by cell viability, proliferation and caspase activation assays we found that Sunitinib inhibits adrenocortical cell viability acting, at least in part, through EGFR, that, in turn, is crucial for EGF proliferative effect on adrenocortical cells. The latter depends, at least in part, on ERK 1/2 activation. An EGFR selective inhibitor was highly effective in reducing cell viability in an adrenocortical tumor primary culture and in the SW13 cells, which express high EGFR levels. Our results suggest that EGFR inhibitors could represent effective therapeutic tools in ACC patients whose tumors express high EGFR levels, that, in turn, may be considered a predictive factor of response. Accurate molecular tumor profiling is crucial to predict drug efficacy and to tailor ACC patients therapeutic approach.