Caspase activity was assessed in OSCC cell lines with the Caspase-Glo 3/7 system. Serum GDF 15 concentrations from 64 patients with histopathological proven OSCC and from 30 healthy volunteers were measured using an enzyme-linked immunosorbent assay. In 21 patients, serum GDF 15 was also analyzed postoperatively.
In vitro, treatment of OSCC cell lines with GDF 15 reduced Caspase 3/7 activity significantly (p < 0.05). In vivo, serum GDF 15 concentrations of the OSCC patients in all stages of OSCC were significantly higher than those of the healthy subjects (p < 0.0001). After surgery, GDF 15 concentrations declined significantly from 1545 卤 774 pg/ml preoperative to 953 卤 438 pg/ml postoperative (p = 0.003). The median survival time of OSCC patients with GDF 15 levels below 875 pg/ml was significantly higher than of OSCC patients with GDF 15 levels above or equal 875 pg/ml (p = 0.031). Determination of receiver operating characteristic curves (ROC) showed a respective area under the ROC curve (AUC) of 0.943.
The anti-apoptotic effect of GDF 15 in OSCC cell lines was shown in vitro. In vivo, significant elevated serum GDF 15 levels with prognostic value in OSCC-patients were seen for the first time. The results indicate that GDF15 may be used as a potential marker for diagnosis and prognosis of this entity.