Abstract
Glioblastoma (GB) is the most common malignant brain tumor in adults. It has limited treatment opportunities and is almost exclusively fatal. Owing to the central role the insulin-like growth factor-1 receptor (IGF-1R) plays in malignant cells, it has been suggested as a target for anticancer therapy including GB. The cyclolignan picropodophyllin (PPP) inhibits IGF-1R without affecting the highly homologous insulin receptor. Here, we show that PPP inhibits growth of human GB cell lines along with reduced phosphorylation of IGF-1R and AKT. In vivo, PPP-treatment causes dramatic tumor regression not only in subcutaneous xenografts but also in intracerebral xenografts, indicating passage of PPP across the blood-brain barrier.