ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of different X-ray doses on the expression of nuclear factor-kappaB (NF-kappaB) P65 in human oral squamous cell carcinoma cell (OSCC) line and the relationship between NF-kappaB P65 and radiation-induced OSCC cell line apoptosis.</p><p><b>METHODS</b>The squamous cell carcinoma of Tca8113 cell was cultivated in the 37 degrees C, 5% CO2 incubator after recovery. The experiment samples were divided into six groups (control group, 2, 4, 6, 8, 10 Gy). After growing to logarithm period, Tca8113 cells were irradiated using above-mentioned X-ray doses. The immunocyteochemistry and Western blot were used to detect the expression of NF-kappaB P65 after irradiation in various times (1, 3, 6, 10, 24, 48 h). The apoptosis rates under different radiotherapy dose were detected by flow cytometer and TDT-mediated dUTP-biotin nick end labeling (TUNEL).</p><p><b>RESULTS</b>Compared with the control group, cytoplasm expression of P65 under different X-ray doses had statistically significant differences (P < 0.05). While the cytoplasm P65 protein expression at different time were compared each other, the 3 h group demonstrated significant difference (P < 0.05). Apoptosis rates in various groups, compared with control group, had statistically significant differences (P < 0.05). While the groups at different time points were compared each other, the apoptosis rates of 3 h group had significant differences (P < 0.05).</p><p><b>CONCLUSION</b>X-ray can activate the NF-kappaB P65 in oral squmaous cell carcinoma cell lines. The correlation between expressional quantity of P65 and radiotherapy induced apoptosis of oral squamous cell carcinoma cell lines possesses positive correlation. The activated and intranuclear P65 may have radiotherapy resistant effect.</p>