Effect of Small Interfering RNA Targeting Hypoxia-inducible Factor-1伪 on Radiosensitivity of PC3 Cell Line

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• 作者：Yuhua Huang^a ; Jiang Yu^b ; Chunyin Yan^a ; ^{yanchunyin_sdfyy@yahoo.cn} ; Jianquan Hou^a ; Jingxian Pu^a ; Guangbo Zhang^c ; Zhenyu Fu^a ; Xizhi Wang^b
• 刊名：Urology
• 出版年：2012
• 期刊代码：267_00904295
• 类别：med
• 出版时间：March, 2012
• 卷：79
• 期：3
• 页码：744.e17-744.e24
• 文件大小：612 K

摘要

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Objective

To evaluate the effect of silencing hypoxia-inducible factor-1伪 (HIF-1伪) expression by small interfering RNA (siRNA) on the radiosensitivity of the PC3 cell line.

Methods

The expression of HIF-1伪 in PC3, a p53-null and androgen-independent prostate cancer cell line, was knocked down by siRNA. Irradiation was performed at 48 hours after transfection. The cells were divided into 3 groups: the PC3 group, control group (transfected with scramble siRNA), and HIF-1伪 silence group. HIF-1伪 expression was determined using real-time polymerase chain reaction and Western immunoblotting. A clonogenic assay and the cell counting kit-8 assay were performed to determine the radiosensitivity. Flow cytometry was used to assess apoptosis and cell cycle distribution.

Results

HIF-1伪 siRNA downregulated HIF-1伪 expression in PC3 cells on the mRNA level and protein level, and its silencing effect on mRNA level was evident at 24-72 hours. The HIF-1伪 silence group had a low final slope of exponential part of a radiation survival curve, survival fraction of 2 Gy, quasi-threshold dose, and extrapolation number, and the sensitizing enhancement ratio was 1.24. The cell counting kit-8 assay showed decreased cellular viability (24 hours, F = 139.74, P < .01; 48 hours, F = 495.49, P < .01; 72 hours, F = 426.89, P < .01; 96 hours, F = 471.11, P < .01) in the HIF-1伪 silence group. Silencing HIF-1伪 also induced more apoptosis (PC3, 17.9%卤 1.65%; control group, 18.6%卤 1.37%; HIF-1伪 silence group, 29.1%卤 2.16%; F = 169.9, P < .01) and cell cycle arrest at the S, G₂/M phase.

Conclusion

The suppression of HIF-1伪 in PC3 cells sensitizes the PC3 cells to irradiation. We have shown that HIF-1伪 inhibition attenuates repair of postradiation injury, with an increase in both interphase death and reproductive death after irradiation, apoptotic potential, and cell cycle arrest at the proliferative phase.