Radiation Induced Cell Line SHG-44 Upregulation Of Cyclooxygenase-2 And Celecoxib: An Inhibitor Of Cyclooxygenase-2 Enhanced Glioma Radiation Effect

Objective: To investigate the change of radiosensitivity and the COX-2 expression of the surviving progeny from the irradiated human glioma cell SHG-44(SHG-44_10Gy). To observe the ability of celecoxib to sensitize three strains of glioma cells to radiation in vitro, And to probe the possible mechanism of celecoxib's radiosensitization.Methods: Radiosensitivity of SHG-44 and SHG-44_10Gy cells was measured by clongenic assay; the COX-2 mRNA and protein expression of SHG-44 and SHG-44_10Gy were detected by RT-PCR and immunocytochemisty staining, the subtoxic dose of celecoxib was chosen to do the radiosensitive experiment to SHG-44 cells,SF767 cells,C6 cells. The cells were planted into two groups,one is radiation only(group R), the other is radiation combind with celecoxib(group R+D). Celecoxib's radiosensitization was measured by clongenic assay.Results: The declined radiosensitivity was detected in the SHG-44_10Gy, upregulation of COX-2 expression in protein and mRNA levels in SHG-44_10Gy were found. There are buffy granules in cytoplasm and cell membrane of SHG-44 cells in the immunocytochemisty staining experiment, the same phenomenon also can be found in SHG-44_10Gy cell,but the staining is deeper .The result of RT-PCR manifest that higher expression of COX-2 mRNA in SHG-44_10Gy,it was significantly different between SHG-44 and SHG-44_10Gy cells (P<0.01). Furthermore, the value of SF₂ was positive correlation with the expression of COX-2 mRNA(P<0.01).Celecoxib displayed radiosensitizing effect in the three glioma cells. The survival curve and the related parameters indicated that Celecoxib could enhance the radisensitivity...