Study Of Radiosensitizing Effect And Mechanisms By CAPE On Human Hela Cells Of Cervical Cancer

Objective This study was to investigate the effect of caffic acid phenethyl ester (CAPE), a component of propolis,on the radiosensitivity of Hela cells. The thesis contained: the drug's influence on the proliferation of Hela cells, radiosensitizing effect and cell cycle of the cells and expression level of cell cycle regulatory protein cyclinB1 after the cells treated by 60Coγray. The data showed a primary investigation of CAPE radiosensitizing mechanisms.Methods (1) MTT assay was used to measure the inhibition effect of different concentration and time by caffic acid phenethyl ester (CAPE) on human Hela cells of cervical cancer. (2) Cloning survival assay and MNCF-T were used to study the radiosensitizing effect of CAPE acting on Hela cells (3) Flow cytometric analysis was adopted to detect the changes of cell cycle distribution induced by CAPE after 60Coγirradiation, and with western-blot to examine the CyclinB1 expression.Results (1) The inhibition of CAPE acting on human Hela cells of cervical cancer increased with concentrations(P<0.01), CAPE concentration with 20% of the inhibition rate is 20μg/ml.(2)The inhibition of CAPE acting on Hela cells was in a time-dependent manner(P<0.01). (3) Hela cells cloning survival decreased with the increase of radiation dose(P<0.01).At the same radiation dose, Human Hela cells cloning survival in combination group was less than in the sole irradiation group(P<0.01),The mean lethal dose(D0) (1.82Gy,1.45Gy)and the quasi-threshold dose(Dq) (3.21Gy,1.89Gy) of Hela cells in combination group decreased comparing with the sole irradiation group,SER was 1.26.(4) At the same radiation dose, MNF and MNCF in combination group was higher than in sole irradiation group(P <0.01), and MNF and MNCF of the two was positively correlated with the radiation dose, may be fitting the dose-effect of linear equation y = a + bD. (5) Compared with the control group, cells in G2/M phase of CAPE group and the sole irradiation group increased (P <0.01), while in the combination group decreased (P <0.05). (6) CyclinB1 protein expression reduced as the radiation dose increases between CAPE combination group and the sole irradiation one under the same radiation dose, CyclinB1 expression of Hela cells in combination group was less than the sole irradiation.Conclusion (1) The inhibition of CAPE acting on human Hela cells of cervical cancer increased with concentrations. (2) CAPE acting on Hela cells in a time-dependent inhibition. (3) Cloning survival negatively correlated with radiation dose. At the same radiation dose, Hela cells cloning survival was less in combination group than in sole irradiation one. Radiosensitizing effect by CAPE on cells may be related to the inhibition of the sub-lethal damage repair. (4) MNF and MNCF between combination group and the sole irradiation one were positively correlated with the radiation dose. At the same radiation dose,the former was higher than the latter. (5) CAPE acting on Hela cells may be correlation with G2/M arrest. (6) Compared with the sole irradiation group, cyclinB1 expression level decreased in combination group.