RESUMO
ObjectiveTo explore the effects of small interfering RNA (siRNA) specific to Bcl-2gene on radiosensitivity of esophageal cancer cells. Methods Bcl-2 gene siRNA ( Bcl-2 siRNA ) was induced into esophageal cancer EC9706 cells by lipofectamine.Bcl-2 protein expression and apoptosis of EC9706 cells were detected by flowcytometer. Clone forming assay was used to determine the inhibitory effects of X-ray radiation combined with Bcl-2 siRNA interference. ResultsWhen Bcl-2 siRNA had been induced into EC9706 cells, Bcl-2 protein expression in EC9706 cells was inhibited, and cell apoptosis was increased. Bcl-2 protein expression rates of EC9706 cells induced with Bcl-2 siRNA1, A2, A3 (25.13％ ±2. 04％ ,38.87％ ± 3.34％ , 30.55％ ± 2. 73％ ) were lower than the control group ( 84.28％ ± 1. 47％ )(t =4. 01,3.04,3.64, P ＜ 0. 05 ). After interference, the apoptosis rate of EC9706 cells ( 33.86％ ±1.04％ ) was higher than the control group and siRNA negative group (5.51％ ±0. 14％ and 5.59％ ±0. 46％ ) (t =6. 55,6. 54,P ＜0. 01 ). Bcl-2 gene siRNA interference enhanced X-ray inducing apoptosis of EC9706 cells (56.76％ ± 1.24％ ), which was higher than the radiation alone group ( 24.51％ ± 0. 48％ )(t =3.59,P ＜ 0. 05 ). The D0, Dq, and SF2 of combined treatment group were much lower than those of irradiation alone group . The sensitization enhancing ratio was 1.32 ( ratio of D0 values ) . Conclusions Bcl-2 gene siRNA could enhance the radiosensitivity of esophageal cancer EC9706 cells and may has a good future in clinical practice.
RESUMO
Objective To establish a radioresistant human cell line from esophageal squamous car-cinoma cells and detect the marker expression of cancer stem cells (CSCs). Methods A radioresistant hu-man esophageal squamous carcinoma cell line KYSE-150R was established by fractionated irradiation. Mor-phological changes from KYSE-150 to KYSE-150R were observed by phase- contrast microscopy. Karyotype analysis was performed by G-banding. The radiosensitivity of these two cell lines was assessed by colony for-marion assays. The cell cycle distribution was assayed by flow cytometry. CSCs markers of β-catenin and In-tegrin-β_1 were measured by Western Blot. Results The population doubling time of KYSE-150 and KYSE-150R were (23.62±0.23) hrand (25.90±0.55) hr, respectively (t =6.62,P=0.00). The numbers of chromosomes in KYSE-150R cells were increased and chromosome aberrations were observed. The SF_2, D_0, D_q and N values of KYSE-150R were all higher than those of KYSE-150. The ratio of D_0 values was 1.21. After irradiation, the number of S-phase cells of KYSE-150 increased from 45.35%±4.03% to 55.09%± 1.70% (t = -3.86,P=0.02) and G2/M phase cells decreased from 9.91%±3.83% to 1.15%±0.32% (t = 3.95, P = 0.02). However, no apparent change of cell cycle distribution for KYSE- 150R was observed. The expression levels of CSCs markers, β-catenin and Integrin-β_1 in KYSE-150R were about 2 times of those in KYSE-150. Conclusions The new cell line KYSE-150R is more radioresistant than its parental cell line KYSE-150. The CSCs in KYSE-150R is more than those in KYSE-150, which may suggest that CSCs is re-lated with the radioresistance.