Nisar Hasan, Sanchidrián González Paulina Mercedes, Labonté Frederik M, Schmitz Claudia, Roggan Marie Denise, Kronenberg Jessica, Konda Bikash, Chevalier François, Hellweg Christine E
Department of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), 51147 Cologne, Germany.
Department of Medical Sciences, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad 44000, Pakistan.
Int J Mol Sci. 2024 Apr 19;25(8):4495. doi: 10.3390/ijms25084495.
Cellular hypoxia, detectable in up to 80% of non-small cell lung carcinoma (NSCLC) tumors, is a known cause of radioresistance. High linear energy transfer (LET) particle radiation might be effective in the treatment of hypoxic solid tumors, including NSCLC. Cellular hypoxia can activate nuclear factor κB (NF-κB), which can modulate radioresistance by influencing cancer cell survival. The effect of high-LET radiation on NF-κB activation in hypoxic NSCLC cells is unclear. Therefore, we compared the effect of low (X-rays)- and high (C)-LET radiation on NF-κB responsive genes' upregulation, as well as its target cytokines' synthesis in normoxic and hypoxic A549 NSCLC cells. The cells were incubated under normoxia (20% O) or hypoxia (1% O) for 48 h, followed by irradiation with 8 Gy X-rays or C ions, maintaining the oxygen conditions until fixation or lysis. Regulation of NF-κB responsive genes was evaluated by mRNA sequencing. Secretion of NF-κB target cytokines, IL-6 and IL-8, was quantified by ELISA. A greater fold change increase in expression of NF-κB target genes in A549 cells following exposure to C ions compared to X-rays was observed, regardless of oxygenation status. These genes regulate cell migration, cell cycle, and cell survival. A greater number of NF-κB target genes was activated under hypoxia, regardless of irradiation status. These genes regulate cell migration, survival, proliferation, and inflammation. X-ray exposure under hypoxia additionally upregulated NF-κB target genes modulating immunosurveillance and epithelial-mesenchymal transition (EMT). Increased IL-6 and IL-8 secretion under hypoxia confirmed NF-κB-mediated expression of pro-inflammatory genes. Therefore, radiotherapy, particularly with X-rays, may increase tumor invasiveness in surviving hypoxic A549 cells.
细胞缺氧在高达80%的非小细胞肺癌（NSCLC）肿瘤中均可检测到，是已知的放射抗性原因。高传能线密度（LET）粒子辐射可能对包括NSCLC在内的缺氧实体瘤治疗有效。细胞缺氧可激活核因子κB（NF-κB），其可通过影响癌细胞存活来调节放射抗性。高LET辐射对缺氧NSCLC细胞中NF-κB激活的影响尚不清楚。因此，我们比较了低（X射线）和高（碳离子）LET辐射对常氧和缺氧A549 NSCLC细胞中NF-κB反应基因上调及其靶细胞因子合成的影响。将细胞在常氧（20% O₂）或缺氧（1% O₂）条件下孵育48小时，然后用8 Gy X射线或碳离子照射，在固定或裂解前维持氧条件。通过mRNA测序评估NF-κB反应基因的调控。通过酶联免疫吸附测定（ELISA）对NF-κB靶细胞因子白细胞介素-6（IL-6）和白细胞介素-8（IL-8）的分泌进行定量。无论氧合状态如何，与X射线相比，A549细胞暴露于碳离子后NF-κB靶基因表达的倍数变化增加更大。这些基因调节细胞迁移、细胞周期和细胞存活。无论照射状态如何，缺氧条件下激活的NF-κB靶基因数量更多。这些基因调节细胞迁移、存活、增殖和炎症。缺氧条件下的X射线照射额外上调了调节免疫监视和上皮-间质转化（EMT）的NF-κB靶基因。缺氧条件下IL-6和IL-8分泌增加证实了NF-κB介导的促炎基因表达。因此，放疗，尤其是X射线放疗，可能会增加存活的缺氧A549细胞的肿瘤侵袭性。
