Expressions of Fas/DcR3 and RGD-FasL mediated apoptosis in pituitary adenomas.

PURPOSE To detect the expressions of Fas/DcR3 and to investigate the cytotoxic effects of RGD-FasL on pituitary adenoma cells. MATERIALS AND METHODS Fas/DcR3 mRNAs were detected by Reverse transcription polymerase chain reaction (RT-PCR) and their surface expressions were measured by flow cytometry. Cytotoxicities exerted by FasL and newly-constructed RGD-FasL on tumor cells were measured with 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The apoptotic cells were examined by electron microscopy and the induced apoptosis was determined by agarose gel electrophoresis. The cell cycle was assessed by flow cytometry with ANNEXIN V FITC/PI. The expressions of caspases, Bcl-2, RANKL and JNK2 were detected by Western blotting. RESULTS Fas/DcR3 was expressed in GH3/MMQ/AtT20 cells. The cytotoxic effects of RGD-FasL on tumor cells were seen in a dose-dependent manner. These cells showed the same sensitivity to RGD-FasL as to FasL. RGD-FasL induced apoptosis and G1/G0 arrest. The expressions of caspase-8/9/3, RANKL, JNK2 were increased while that of Bcl-2 was decreased with treatment of RGD-FasL. CONCLUSIONS Fas can be a novel target for the treatment of pituitary adenomas. RGD-FasL induces apoptosis of pituitary adenoma cells through caspase activation.