Mutated focal adhesion kinase induces apoptosis in a human glioma cell line, T98G

Abstract

We have established that focal adhesion kinase (FAK)-transfected HL-60 (HL-60/FAK) cells were highly resistant to hydrogen peroxide and etoposide-induced apoptosis compared to vector-transfected cells. Mutagenesis study revealed that Y397 is required for anti-apoptotic activity in HL-60/FAK, since Y397F-mutated FAK (397FAK) lost anti-apoptotic function. Assuming that 397FAK functions as a dominant negative FAK, we introduced 397FAK cDNA into a human glioma cell line, T98G, using an adenoviral vector. We found that 397FAK induced marked apoptosis with significant FAK degradation. As PI3-kinase–Akt survival pathway was constitutively activated in T98G cells, we hypothesized that this pathway was shut off by 397FAK gene transfection. As expected, activation of PI3-kinase–Akt survival pathway was decreased by the 397FAK gene transfection. 397FAK activated mainly caspase-6 which induced degradation of transfected FAK as well as endogenous FAK. These results indicated that 397FAK induces apoptosis in T98G cells, by interrupting signals of FAK leading to the survival pathway in T98G glioma cells.