Zellweger Tobias, Chi Kim, Miyake Hideaki, Adomat Hans, Kiyama Satoshi, Skov Kirsten, Gleave Martin E
The Prostate Centre, Vancouver General Hospital, Vancouver, British Columbia V6H 3Z6, Canada.
Clin Cancer Res. 2002 Oct;8(10):3276-84.
The purpose of this study is to evaluate the role of the cell survival gene clusterin in radiation-induced cell death in human LNCaP and PC-3 prostate cancer models.
Radiation sensitivities were compared in parental and clusterin-overexpressing LNCaP cells and in PC-3 cells and tumors treated with antisense or mismatch clusterin oligonucleotides.
Clusterin-overexpressing LNCaP cells were less sensitive to irradiation with significantly lower cell death rates (23% after 8 Gy) compared with parental LNCaP cells (50% after 8 Gy) 3 days after irradiation. Clusterin expression in PC-3 cells after radiation was found to be up-regulated in a dose-dependent manner in vitro by 70% up to 12 Gy and in vivo by 84% up to 30 Gy. Inhibition of clusterin expression in PC-3 cells using antisense oligonucleotides (ASOs) occurred in a sequence- and dose-dependent manner and significantly enhanced radiation-induced apoptosis and decreased PC-3 cell growth rate and plating efficiency. Compared with mismatch control oligonucleotide treatment, clusterin ASO treatment enhanced radiation therapy and significantly reduced PC-3 tumor volume in vivo by 50% at 9 weeks. In addition, TUNEL staining revealed increased number of apoptotic cells in clusterin ASO-treated and irradiated PC-3 tumors, compared with treatment with mismatch control oligonucleotides plus radiation.
These findings support the hypothesis that clusterin acts as a cell survival protein that mediates radioresistance through the inhibition of apoptosis. In vivo results further suggest that inactivation of clusterin using ASO technology might offer a novel strategy to improve results of radiation therapy for prostate cancer patients.
本研究旨在评估细胞存活基因簇蛋白在人LNCaP和PC-3前列腺癌模型辐射诱导的细胞死亡中的作用。
比较亲本细胞和过表达簇蛋白的LNCaP细胞以及用反义或错配簇蛋白寡核苷酸处理的PC-3细胞及肿瘤的辐射敏感性。
过表达簇蛋白的LNCaP细胞对辐射的敏感性较低，与亲本LNCaP细胞相比，照射后3天细胞死亡率显著降低（8 Gy后为23%），而亲本LNCaP细胞（8 Gy后为50%）。在体外，PC-3细胞辐射后簇蛋白表达呈剂量依赖性上调，最高可达12 Gy时上调70%，在体内最高可达30 Gy时上调84%。使用反义寡核苷酸（ASO）抑制PC-3细胞中的簇蛋白表达呈序列和剂量依赖性，显著增强辐射诱导的凋亡，并降低PC-3细胞生长速率和平板效率。与错配对照寡核苷酸处理相比，簇蛋白ASO处理增强了放射治疗效果，并在9周时使体内PC-3肿瘤体积显著减少50%。此外，TUNEL染色显示，与错配对照寡核苷酸加辐射处理相比，簇蛋白ASO处理并照射的PC-3肿瘤中凋亡细胞数量增加。
这些发现支持以下假设，即簇蛋白作为一种细胞存活蛋白，通过抑制凋亡介导放射抗性。体内结果进一步表明，使用ASO技术使簇蛋白失活可能为改善前列腺癌患者放射治疗效果提供一种新策略。
