Multiple genetic aberrations in human gliomas contribute to their highly infiltrative and rapid growth characteristics. Focal adhesion kinase (FAK) regulates tumor migration and invasion. Insulin-like growth factor-I receptor (IGF-IR), whose expression correlates with tumor grade, is involved in proliferation and survival. We hypothesized that inhibiting the phosphorylation of FAK and IGF-IR by NVP-TAE226 (hereafter called TAE226), a novel dual tyrosine kinase inhibitor of FAK and IGF-IR, would suppress the growth and invasion of glioma cells. In culture, TAE226 inhibited extracellular matrix -induced autophosphorylation of FAK (Tyr 397 ). TAE226 also inhibited IGF-I -induced phosphorylation of IGF-IR and activity of its downstream target genes such as MAPK and Akt. TAE226 retarded tumor cell growth as assessed by a cell viability assay and attenuated G 2 -M cell cycle progression associated with a decrease in cyclin B1 and phosphorylated cdc2 (Tyr 15 ) protein expression. TAE226 treatment inhibited tumor cell invasion by at least 50% compared with the control in an in vitro Matrigel invasion assay. Interestingly, TAE226 treatment of tumor cells containing wild-type p53 mainly exhibited G 2 -M arrest, whereas tumor cells bearing mutant p53 underwent apoptosis. Induction of apoptosis by TAE226 was substantiated by detection of caspase-3/7 activation and poly(ADP-ribose) polymerase cleavage and by an Annexin V apoptosis assay. More importantly, TAE226 treatment significantly increased the survival rate of animals in an intracranial glioma xenograft model. Collectively, these data show that blocking the signaling pathways of FAK and IGF-IR with TAE226 has the potential to be an efficacious treatment for human gliomas.

Aberrant genetic alternations in human gliomas, such as amplification of epidermal growth factor receptor, mutation and/or deletion of tumor suppressor gene PTEN, and mutations of PIK3CA, contribute to constitutive activation of the phosphatidylinositol 3-kinase (PI3K) pathway. We investigated the potential antitumor activity of NVP-BEZ235, which is a novel dual PI3K/mammalian target of rapamycin (mTOR) inhibitor in gliomas. The compound suppressed glioma cell proliferation with IC 50 values in the low nanomolar range by specifically inhibiting the activity of target proteins including Akt, S6K1, S6, and 4EBP1 in the PI3K/ Akt/mTOR signaling pathway. NVP-BEZ235 treatment of glioma cell lines led to G 1 cell cycle arrest and induced autophagy. Furthermore, expression of the vascular endothelial growth factor (VEGF), which is an important angiogenic modulator in glioma cells, was significantly decreased, suggesting that NVP-BEZ235 may also exert an antiangiogenic effect. Preclinical testing of the therapeutic efficacy of NVP-BEZ235 showed that it significantly prolonged the survival of tumor-bearing animals without causing any obvious toxicity. Tumor extracts harvested from animals after treatment showed that the compound inhibited the activity of target proteins in the PI3K/Akt/mTOR cascade. Immunohistochemical analyses also showed a significant reduction in staining for VEGF von Willebrand factor (factor VIII) in NVP-BEZ235-treated tumor sections compared with controls, further confirming that NVP-BEZ235 has an antiangiogenic effect in vivo. We conclude from these findings that NVP-BEZ235 antagonizes PI3K and mTOR signaling and induces cell cycle arrest, down-regulation of VEGF, and autophagy. These results warrant further development of NVP-BEZ235 for clinical trials for human gliomas or other advanced cancers with altered PI3K/Akt/mTOR signaling.

Purpose The aim of this study was to show preclinical efficacy and clinical development potential of NVP-BKM120, a selective pan class I phosphatidylinositol-3 kinase (PI3K) inhibitor in human glioblastoma (GBM) cells in vitro and in vivo. Experimental Design The effect of NVP-BKM120 on cellular growth was assessed by CellTiter-Blue assay. Flow cytometric analyses were carried out to measure the cell-cycle, apoptosis, and mitotic index. Mitotic catastrophe was detected by immunofluorescence. The efficacy of NVP-BKM120 was tested using intracranial U87 glioma model. Results We tested the biologic effects of a selective PI3K inhibitor NVP-BKM120 in a set of glioma cell lines. NVP-BKM120 treatment for 72 hours resulted in a dose-dependent growth inhibition and effectively blocked the PI3K/Akt signaling cascade. Although we found no obvious relationship between the cell line's sensitivity to NVP-BKM120 and the phosphatase and tensin homolog (PTEN) and epidermal growth factor receptor (EGFR) statuses, we did observe a differential sensitivity pattern with respect to p53 status, with glioma cells containing wild-type p53 more sensitive than cells with mutated or deleted p53. NVP-BKM120 showed differential forms of cell death on the basis of p53 status of the cells with p53 wild-type cells undergoing apoptotic cell death and p53 mutant/deleted cells having a mitotic catastrophe cell death. NVP-BKM120 mediates mitotic catastrophe mainly through Aurora B kinase. Knockdown of p53 in p53 wild-type U87 glioma cells displayed microtubule misalignment, multiple centrosomes, and mitotic catastrophe cell death. Parallel to the assessment of the compound in in vitro settings, in vivo efficacy studies using an intracranial U87 tumor model showed an increased median survival from 26 days (control cohort) to 38 and 48 days (treated cohorts). Conclusion Our present findings establish that NVP-BKM120 inhibits the PI3K signaling pathways, leading to different forms of cell death on the basis of p53 statuses. Further studies are warranted to determine if NVP-BKM120 has potential as a glioma treatment.

Purpose: Inflammatory breast cancer (IBC) is a rare but aggressive type of advanced breast cancer. Epidermal growth factor receptor (EGFR) expression is an independent poor prognostic factor in IBC. The purpose of this study was to determine the effect on IBC tumorigenicity and metastasis of blocking the EGFR pathway. Experimental Design: IBC cell lines, which express high level of EGFR, were treated with EGFR small interfering RNA and with the EGFR tyrosine kinase inhibitor erlotinib. The role of EGFR in IBC cell proliferation, motility, invasiveness, and change of the expression levels of epithelial-mesenchymal transition markers was examined. The role of extracellular signal-regulated kinase (ERK)-1/2 in erlotinib activity was also studied. The activity of erlotinib in tumor growth and metastasis was examined in an orthotopic xenograft model of IBC. Results: Erlotinib inhibited proliferation and anchorage-independent growth of IBC cells, and this inhibition was ERK dependent. Erlotinib inhibited cell motility and invasiveness and reversed the mesenchymal phenotype of IBC cells to epithelial phenotype in three-dimensional culture. Erlotinib dramatically inhibited IBC tumor growth in a xenograft model. Interestingly, erlotinib inhibited spontaneous lung metastasis, even at a low dose that had no significant effect on primary tumor growth. These erlotinib-treated tumors were converted to epithelial phenotype from mesenchymal phenotype. Conclusions:The EGFR pathway is involved in tumor growth and metastasis of IBC. Targeting EGFR through the ERK pathway may represent an effective therapeutic approach to suppress tumorigenicity and prevent metastasis in EGFR-expressing IBC. (Clin Cancer Res 2009;15(21):6639-48) Inflammatory breast cancer (IBC) is a rare but very aggressive type of advanced breast cancer that accounts for 1% to 5% of all breast cancer cases in the United States (1, 2). IBC can initially present as either stage IIIB locally advanced or stage IV breast cancer (3). IBC is characterized by extensive lymphovascular invasion and is associated with a high risk of distant metastases (4). Even when treated with multimodality strategies including chemotherapy, surgery, and radiation therapy, IBC is associated with a poor long-term outcome and a high risk of recurrence and metastasis compared with noninflammatory locally advanced breast cancer. The 3-year survival rate among IBC patients is only about 40%, much lower than the 85% 3-year survival rate among patients with non-IBC (5). To date, effective standard therapies for IBC are limited. Therefore, novel therapeutic approaches need to be developed. Studying the biological basis of IBC will allow us to develop novel targeted therapies to improve the outcome of IBC.It is reported that up to 30% of IBC patients have distant metastases at the time of diagnosis, in contrast to 5% of patients with non-IBC (6). The lower survival rate of patients with IBC is thought to be due to the highly metastatic nature of the disease. An important event during ma...