Figure 1.
Subunits of system are expressed in glioma cell lines and patient tumor samples. A, RT-PCR indicated that transcripts of catalytic subunit xCT and the regulatory subunit 4F2hc of system are expressed in primary cultures of rat astrocytes and all glioma cell lines tested; four lines are shown. B, protein expression of xCT and 4F2hc are shown in human astrocytes and five human glioma cell lines. This is compared with the glutamate transporter GLT-1, expressed robustly in mature astrocytes but less so in human fetal astrocytes (immature). C, protein expression of system subunits in five GBM patient tissues are shown from individuals aged 51 to 72 y. β-Actin is shown as a control for protein loading efficiency. The approximate molecular weights of the proteins are indicated to the right as each blot image was cropped for clarity.