ABSTRACT
Objective To investigate the effects of TLR4 on the radiosensitivity of tumor cells.Methods The cell lines of RAW264.7,Lewis,MFC,Hepal-6,Bl6,and NIH3T3 were irradiated with 5 Gy X-rays or sham-irradiated.24 h after irradiation,the expression of TLR4 was detected by flow cytometry.According to the TKR4 level,cells were divided into three groups:without treatment,LPS stimulation and TAK242 block.CCK-8 kit and Annexin-V Apoptosis Kit were used to detect cell proliferation,apoptosis and cell cycle distribution of each group.Results After 24 h of 5 Gy ionizing radiation,TLR4 was significantly increased in Lewis cells (t =-8.68,P ＜0.01) but decreased in MFC cells (t =25.8,P ＜ 0.01) and had no significant changes in Hepal-6,B16 and RAW264.7 cells.In addition,the proliferation vitality (t =57.62,-6.23,P ＜ 0.01) and survival fraction (t =13.37,19.24,P ＜ 0.01) of the Lewis and MFC cells were reduced especially for the TLR4-blocked cells,and the apoptosis rates of both Lewis (t=-167.85,P＜0.01) and MFC cells (t=-26.45,P＜0.01) were elevated.The percentages of G0/G1 phase and S phase Lewis cells were significant increased (t =8.68,14.89,P ＜ 0.01) but its G2/M phase were reduced (t =-37.48,P ＜ 0.01).However,the percentages of G0/G1 phase and S phase MFC cells were obviously reduced (t =20.31,4.48,P ＜ 0.01) and G2/M phase increased (t =-13.06,P ＜ 0.01).For both cell lines of Lewis and MFC,the cycle distribution of TAK242 and LPS groups didn't change significantly.Conclusions High expression TLR4 in the Lewis cells is related to cell proliferation and apoptosis but not cell cycle distribution,and hence TLR4 could influence the radiosensitivity of tumor cells.
ABSTRACT
Objective To explore the role of PLC/PIP2 signal pathway in the changes of mouse thymus CD4 + CD25 + NRP1 + Treg and TGF-β1 after different doses of X-ray irradiation Methods 36 ICR mice were randomly divided into 6 groups according to the irradiation doses of 0,0.5,1.0,2.0,4.0 and 6.0 Gy,respectively.Flow cytometry was used to detect the expression of NRP1 + Treg,and ELISA was used to detect the expression of TGF-β1 in mouse thymocytes at 16 h post-irradiation.The EL-4 cells were irradiated by X-rays at the dose of 4.0 Gy after co-cultured with the PMA and TMB-8 for 2 hours.Flow cytometry was used to detect the expression of NRP1 + Treg,and ELISA was used to detect the changes of TGF-β1 at 48 h post-irradiation.Results The NRP1 + Treg appeared a transient decrease at both 0.5 and 1.0 Gy irradiation and reached its valley value at 1.0 Gy (t =6.96,P ＜ 0.01),then showed a dosedependent increase and reached its peak at 6.0 Gy (t =6.70,P ＜ 0.01).The TGF-β1 level decreased after 0.5 Gy X-rays (t =12.53,P ＜0.01),then increased at a dose-dependent manner and reached its peak at 4.0 Gy (t =10.40-19.56,P ＜ 0.01).Compared with the sham-irradiation,NRP1 + Treg was decreased significantly after PMA treatment (t =3.06,P ＜ 0.01),while it was up-regulated significantly after irradiation in the presence of PMA (t =8.27,P ＜ 0.01).TGF-β1 was reduced in the presence of PMA with or without irradiation (t =10.46-39.69,P ＜ 0.01).NRP1 + Treg and TGF-β1 were increased significantly after TMB-8 treatment (t =5.53-44.26,P ＜ 0.01).Conclusions NRP1 + Treg cells and TGF-β1 were up-regulated after a high dose radiation,and the PLC/PIP2 signal pathway may participate in the regulation.