[RelB-siRNA enhanced the radiosensitivity of murine prostate cancer cell line RM-1].

ABSTRACT

OBJECTIVE: To explore the transfecting effects of RelB small interfering RNA (RelB-siRNA) on murine prostate cancer cell line RM-1 sensitivity of radiotherapy. METHODS: The RM-1 cells were divided into RelB-siRNA vector, empty vector, non-transfection and normal groups. After transfection, the first three groups were irradiated by X ray. Clone formation array method was used to measure the surviving fraction and the relevant parameter values after 0, 2, 4, 6, 8 Gy irradiation. Apoptotic rate was measured via Annexin V/PI flow cytometry after 6 Gy irradiation. The level of RelBmRNA was estimated by real-time polymerase chain reaction (PCR) after 6 Gy irradiation. And the RelB protein of cytoplasm and nucleus was detected by Western blot after 6 Gy irradiation. RESULTS: Clone formation array showed that RelB group at each dose point corresponding to the survival fraction were lower that the empty vector nd non-transfection groups. The D0, Dq and SF2 values of RelB group were 1.68, 0.60, 0.43, lower than those of empty vector group 1.92, 3.08, 0.89 and non-transfection group 1.93, 2.76, 0.84. Annexin V/PI flow cytometry demonstrated that the apoptotic rate of RelB group was 15.27% ± 1.62% and it was significantly higher than the non-transfection group 7.90% ± 1.50% and the empty vector group 8.40% ± 0.69% respectively (P < 0.01) .Real-time PCR indicated that RelB-mRNA amplification of RelB group was 1.18 ± 0.03 and it was significantly lower than the non-transfection group 2.10 ± 0.61 and the empty vector group 1.97 ± 0.66 respectively (P < 0.01) .Western blot suggested that cytoplasmic gray-scale ratio of RelB group was 0.50 ± 0.08 and it was significantly lower than the non-transfection 1.77 ± 0.19 and the empty group 1.52 ± 0.12 respectively (P < 0.01) . And the nuclear gray-scale radio of the RelB group was 0.18 ± 0.03 and it was significantly lower than the non-transfection group 0.61 ± 0.12 and the empty group 0.54 ± 0.13 respectively (P < 0.01) . The RelB protein inhibition rates of cytoplasmic and nuclear RelB-siRNA were 71.8% and 70.4% respectively. CONCLUSION: RelB-siRNA can effectively inhibit the RelB expression of murine prostate cancer cell line RM-1 and significantly increase its sensitivity to radiotherapy.