Fat mass and obesity associated gene (FTO) has been identified as a novel gene related with obesity in recent years.A large amount of studies report the significant association between FTO expression level and energy metabolism.Besides,epidemiological studies and meta-analysis studies indicate the possibility that FTO gene polymorphism is related with cancer risk such as pancreatic cancer,endometrial cancer,breast cancer and so on.Taken account of the special energy metabolism in cancer cells which is different from that in normal cells,it is rather a novel and hot hypothesis to be investigated that FTO plays an important role in regulating energy metabolism of cancers.

Objective To evaluate the effect of Fat Mass and Obesity Associated (FTO) gene on radiosensitivity of human glioma cell A172 and investigate its potential mechanism by changing the expression of FTO gene.Methods Cells were divided into five groups according to their FTO protein expression level.The normal expression group was recorded as A172 Group,the low-expression and its negative control group was A172/siRNA and A172/NC Group,and the over-expression and its negative control group was A172/FTO and A172/PC group.FTO protein expressions were assayed by Western blot in A172 Group after irradiation.Clonogenic assay was executed to evaluate the relationship between FTO gene and radiosensitivity.Immunofluorescence and Western blot assay were applied to detect the proteins of DNA damage and repair.Results FTO protein expression level in A172 Group was significantly related to the irradiation dose and the time post-irradiation.The radiosensitization ratio (SERD0) of A172/siRNA and A172/FTO group were 1.829 and 0.812 respectively.Not only the number of γ-H2AX foci increased (t =-21.884,P ＜ 0.05) in A172/siRNA 1 h post-irradiation but the decreases of p-p95/NBS1 and Ku80 proteins were also detected (t =24.731,23.293,P ＜ 0.05) together with the increase of Rad50 protein (t =3.140,P ＜ 0.05).But the expressions of these proteins in A172/FTO group were opposite to the above phenomenon (t =0.642,-8.364,26.829,P ＜ 0.05).Conclusions FTO gene is a radiation-resistant gene,which may because the regulation of FTO gene could alter the primary injury and DNA damage repair in the irradiated tumor cells.

Objective To compare the radiosensitivity effect of celecoxib on oln93 and u373 cells,and to explore the related mechanism.Methods Both oln93 cells and u373 cells were respectively divided into control group,drug group,radiation group and combined group when treated with celecoxib and irradiation.Cell survival ratio was evaluated by MTT assay and clogenic assay.Flow cytometry and Western blot assay were used to measure cell cycle and protein expression.Results Celecoxib had a similar effect on oln93 and u373 cells in enhancing the radiosensitivity (t =2.215-30.996,P ＜ 0.05 ; t =0.383-11.732,P＜0.05)and blocking cellcycle in G0/G1(t=-6.1-5.141,P＜0.05).Compared with the radiation group,the combined group showed S phase arrest(t =-18.174,P ＜ 0.05),and increase of Cyclin A protein (t =-8.087,P ＜ 0.05) in oln93 cells,and G2/M arrest and decrease of Cyclin B1 and DNA-PKcs and MRE11 protein (t =-8.838-10.45,P ＜ 0.05) in u373 cells.Conclusions Celecoxib illustrates a more sensitive radiosensitivity to u373 cells by regulating its cell cycle and DNA damage repair.