背景:放射治疗在前列腺癌的治疗中是必不可少的。传统光子放射治疗的替代方法是应用碳离子,这提供了优越的肿瘤内剂量分布和较少的诱导损伤相邻的健康组织。前列腺癌细胞的共同特征是它们对雄激素的依赖性,其在晚期前列腺癌阶段通过雄激素剥夺疗法在治疗上被利用。这里,我们旨在分析前列腺癌细胞对光子照射的转录组反应,与碳离子相比,专注于DNA损伤,DNA修复和雄激素受体信号传导。
方法:用光子或碳离子照射前列腺癌细胞系LNCaP(功能性TP53和雄激素受体信号传导)和DU145(功能失调的TP53和雄激素受体信号传导),并通过免疫-细胞荧光评估随后的DNA损伤。此外,用雄激素受体激动剂处理细胞.通过RT-qPCR和RNA测序研究了辐射和雄激素处理对基因调控和转录组的影响。其次是生物信息学分析。
结果:光子或碳离子辐照后,LNCaP和DU145细胞均显示出剂量依赖性的可见DNA损伤,该损伤随时间减少,表明正在发生DNA修复。在基因调控方面,参与TP53依赖性DNA损伤反应的mRNA在LNCaP中被光子和碳离子显著上调,但在DU145细胞中没有,辐射后基因调控水平普遍较低。LNCaP和DU145细胞都通过下调参与DNA修复和细胞周期的基因来响应光子和碳离子,部分类似于应用的雄激素受体激动剂的转录组反应。光子和碳离子都不会显着影响经典雄激素受体依赖性基因调控。此外,确定了某些受光子或碳离子辐照特异性调节的基因。
结论:光子和碳离子照射在诱导信号通路和转录组反应方面显示出显著的一致性。这些反应受到TP53状态的强烈影响。然而,揭示了依赖于辐射模式的独特基因调控,对放射治疗结果的影响不明确。雄激素受体信号传导和照射在DNA修复和细胞周期方面共享某些基因的调节。
BACKGROUND: Radiotherapy is essential in the treatment of prostate cancer. An alternative to conventional photon radiotherapy is the application of carbon ions, which provide a superior intratumoral dose distribution and less induced damage to adjacent healthy tissue. A common characteristic of prostate cancer cells is their dependence on androgens which is exploited therapeutically by androgen deprivation therapy in the advanced prostate cancer stage. Here, we aimed to analyze the transcriptomic response of prostate cancer cells to irradiation by photons in comparison to carbon ions, focusing on DNA damage, DNA repair and androgen receptor signaling.
METHODS: Prostate cancer cell lines LNCaP (functional TP53 and androgen receptor signaling) and DU145 (dysfunctional TP53 and androgen receptor signaling) were irradiated by photons or carbon ions and the subsequent DNA damage was assessed by immuno-cytofluorescence. Furthermore, the cells were treated with an androgen-receptor agonist. The effects of irradiation and androgen treatment on the gene regulation and the transcriptome were investigated by RT-qPCR and RNA sequencing, followed by bioinformatic analysis.
RESULTS: Following photon or carbon ion irradiation, both LNCaP and DU145 cells showed a dose-dependent amount of visible DNA damage that decreased over time, indicating occurring DNA repair. In terms of gene regulation, mRNAs involved in the TP53-dependent DNA damage response were significantly upregulated by photons and carbon ions in LNCaP but not in DU145 cells, which generally showed low levels of gene regulation after irradiation. Both LNCaP and DU145 cells responded to photons and carbon ions by downregulation of genes involved in DNA repair and cell cycle, partially resembling the transcriptome response to the applied androgen receptor agonist. Neither photons nor carbon ions significantly affected canonical androgen receptor-dependent gene regulation. Furthermore, certain genes that were specifically regulated by either photon or carbon ion irradiation were identified.
CONCLUSIONS: Photon and carbon ion irradiation showed a significant congruence in terms of induced signaling pathways and transcriptomic responses. These responses were strongly impacted by the TP53 status. Nevertheless, irradiation mode-dependent distinct gene regulations with undefined implication for radiotherapy outcome were revealed. Androgen receptor signaling and irradiations shared regulation of certain genes with respect to DNA-repair and cell-cycle.