Table_2_NFATC2 Modulates Radiation Sensitivity in Dermal Fibroblasts From Patients With Severe Side Effects of Radiotherapy.xlsx

Although it is well established that 5 to 15% of radiotherapy patients exhibit severe side-effects in non-cancerous tissues, the molecular mechanisms involved are still poorly known, and the links between cellular and tissue radiosensitivity are still debated. We here studied fibroblasts from non-irradiated skin of patients with severe sequelae of radiotherapy, to determine whether specific basal cell activities might be involved in susceptibility to side-effects in normal tissues. Compared to control cells, patient fibroblasts exhibited higher radiosensitivity together with defects in DNA repair. Transcriptome profiling of dermal fibroblasts from 16 radiotherapy patients with severe side-effects and 8 healthy individuals identified 540 genes specifically deregulated in the patients. Nuclear factor of activated T cells 2 (NFATC2) was the most differentially expressed gene, poorly expressed at both transcript and protein level, whereas the NFATC2 gene region was hypermethylated. Furthermore, NFATC2 expression correlated with cell survival after irradiation. Finally, silencing NFATC2 in normal cells by RNA interference led to increased cellular radiosensitivity and defects in DNA repair. This study demonstrates that patients with clinical hypersensitivity also exhibit intrinsic cellular radiosensitivity in their normal skin cells. It further reveals a new role for NFATC2 as a potential regulator of cellular sensitivity to ionizing radiation.

尽管已有研究证实，5%至15%的放疗患者会在非癌组织中出现严重不良反应，但相关的分子机制仍未明确，且细胞与组织放射敏感性之间的关联尚存争议。本研究针对罹患严重放疗后遗症患者的未照射皮肤成纤维细胞开展研究，旨在明确特定基础细胞活性是否参与调控正常组织对放疗不良反应的易感性。与对照细胞相比，患者来源的成纤维细胞不仅放射敏感性更高，同时存在DNA修复缺陷。本研究对16名出现严重放疗不良反应患者及8名健康个体的真皮成纤维细胞开展转录组分析，共鉴定出540个在患者中特异性表达失调的基因。活化T细胞核因子2（Nuclear factor of activated T cells 2, NFATC2）是差异表达最为显著的基因，其转录本与蛋白水平均表达低下，而NFATC2基因区域则呈现高甲基化状态。此外，NFATC2的表达水平与辐照后的细胞存活情况相关。最后，通过RNA干扰（RNA interference, RNAi）技术沉默正常细胞中的NFATC2，可导致细胞放射敏感性升高及DNA修复缺陷。本研究证实，出现临床放射超敏反应的患者，其正常皮肤细胞也存在内在的细胞放射敏感性。本研究同时揭示了NFATC2的全新功能——其可作为细胞对电离辐射敏感性的潜在调控因子。