Foretinib induces G2/M cell cycle arrest, apoptosis, and invasion in human glioblastoma cells through c-MET inhibition

Abstract

Glioblastoma multiforme (GBM) is one of the most aggressive human cancers. The c-MET receptor tyrosine kinase (RTK) which is frequently deregulated in GBM is considered as a promising target for GBM treatment. The c-MET plays a key role in cell proliferation, cell cycle progression, invasion, angiogenesis, and metastasis. Here, we investigated the anti-tumour activity of foretinib, a c-MET inhibitor, on three human GBM cells (T98G, U87MG and U251). Anti-proliferative effect of foretinib was determined using MTT, crystal violet staining, and clonogenic assays. PI and Annexin V/PI staining flow cytometry were used to evaluate the effects of foretinib on cell cycle and apoptosis, respectively. Scratch assay, qRT-PCR, western blot, and zymography analyses were applied to elucidate the molecular mechanisms underlying the anti-tumour activity of foretinib. Foretinib treatment reduced phosphorylation of c-MET on T98G and U251 cells, but not in U87MG cells. The highest inhibitory effect was observed in T98G cells (IC50 = 4.66 ± 0.29µM) and the lowest one in U87MG cells (IC50 = 29.99 ± 1.31µM). The results showed that foretinib inhibited the proliferation of GBM cells through a G2/M cell cycle arrest and mitochondrial-mediated apoptosis in association with alternation in expression of the related genes and protein-regulated G2/M phase and apoptosis. Foretinib diminished GBM cell invasion through downregulation of the proteolytic cascade of MMP2, uPA and uPAR and epithelial-mesenchymal transition (EMT)-related genes. A different GBM cell sensitivity pattern was noticeable in all experiments which demonstrated T98G as a sensitive and U87MG as a resistant phenotype to foretinib treatment. The results indicated that foretinib might have the therapeutic potential against human GBM which deserve further investigation.