Objective To investigate the effect of E1A gene on the radiosensitivity of human nasopharyngeal carcinoma cells and its possible mechanism. Methods The E1A gene was transfected into nasopharyngeal carcinoma CNE-2R cells by adenovirus vector. The expression of E1A gene was detected by RT-PCR. Untransfected CNE-2R cells(PBS group)and CNE-2R cells transfected with empty vector Ad-β-gal(Ad-β-gal group)and E1A(Ad-E1A group)were given 0 Gy,2 Gy,4 Gy,6 Gy,8 Gy 6 MV X-ray irradiation. The changes in radiosensitivity of CNE-2R cells were determined by colony-forming assay. Flow cytometry was used to analyze cell apoptosis in each group. The expression of NF-κB, CK2α, Bcl-2, and cleaved caspase-3 was measured by Western blot. Results RT-PCR confirmed that the E1A gene was transfected into CNE-2R cells and stably expressed. The Ad-E1A group had a significantly lower plating efficiency than the PBS group and the Ad-β-gal group(P<0.05). The Ad-E1A group had significantly lower cell survival rate at 2 Gy irradiation than the PBS group and the Ad-β-gal group(0.217 vs. 0.602, P<0.05;0.217 vs. 0.585, P<0.05). The Ad-E1A group had a significantly higher α/β value than the PBS group and the Ad-β-gal group(24.680 vs. 5.268, P<0.05;24.680 vs. 5.132, P<0.05). Flow cytometry results showed that irradiation alone could promote the apoptosis of CNE-2R cells,when combined with E1A gene,the apoptosis rate was significantly increased(P<0.05). Western blot results showed that E1A gene down-regulated the expression of NF-κB/p65,CK2α,and Bcl-2 and up-regulated the expression of cleaved caspase-3. Conclusions E1A gene can enhance the radiosensitivity of nasopharyngeal carcinoma cells by inhibiting the expression of CK2 to block the NF-κB signaling pathway and promoting cell apoptosis.

Objective To investigate the effect of Tiopronin (TIP) on interleukin (IL)-2 immunotherapy of human leukemia KG-1 cells and its possible mechanism.Methods KG-1 ceils in logarithmic growth phase were randomly divided into KG-1 + IL-2 group and KG-1 + IL-2 + TIP group.Methyl thiazolyl tetrazolium (MTI) assay and colony formation assay were used to detect the sensitivity and proliferation of KG-1 cells.The changes of reactive nitric metabolites (RNM) were detected with nitrate reductase method.The production of tumor necrosis factor (TNF)-3 and interferon (IFN)-γ,was detected with enzyme linked immunosorbent assay (ELISA).The expression of CD3ξ was detected with Western blot and real time polymerase chain reaction (RT-PCR).Results IL-2 and IL-2 + TIP could inhibit the growth of KG-1 cells.The inhibitory rate of KG-1 + IL-2 + TIP group was significantly higher than that of KG-1 + IL-2 group,and the sensitivity of KG-1 cells to IL-2 was 6.2 times higher.Both IL-2 and IL-2 + TIP group inhibited the colony formation of KG-1 cells.Compared to KG-1 + IL-2 group,KG-1 + IL-2 + TIP group inhibited the colony formation of KG-1 cells by 3.5 times.The RNM production of KG-1 + IL-2 group was (158.26 ± 3.82) μmol/ml,which was significantly higher than (45.18 ± 4.29) μ mol/ml of KG-1 + IL-2 + TIP group (P ＜ 0.05).The levels of TNF-β and IFN-γin KG-1 + IL-2 + TIP group were (253.28 ± 7.84) pg/ml and (181.25 ±6.41) pg/ml,which was significantly higher than (98.45 ±6.43) pg/ml and (68.74 ±8.26) pg/ml of KG-1 +IL-2 group (P＜0.05).The expression of CD3ξ in KG-1 +IL-2 +TIP group was significantly higher than that in KG-1 + IL-2 group.Conclusions Tiopronin can promote NK/T cell activity and increase the sensitivity of leukemia KG-1 cells to IL-2 by eliminating reactive nitrogen metabolites.