Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, South Australia, 5000, Australia.
School of Medicine, University of Adelaide, Adelaide, South Australia, 5000, Australia.
Cancer Rep (Hoboken). 2022 Aug;5(8):e1543. doi: 10.1002/cnr2.1543. Epub 2021 Oct 12.
Platinum-based chemotherapy and radiotherapy are standard treatments for non-small cell lung cancer, which is the commonest, most lethal cancer worldwide. As a marker of treatment-induced cancer cell death, we have developed a radiodiagnostic imaging antibody, which binds to La/SSB. La/SSB is an essential, ubiquitous ribonuclear protein, which is over expressed in cancer and plays a role in resistance to cancer therapies.
In this study, we examined radiation-induced DNA double strand breaks (DSB) in lung cancer cell lines and examined whether La/SSB associated with these DSB.
Three lung cancer lines (A549, H460 and LL2) were irradiated with different X-ray doses or X-radiated with a 5 Gy dose and examined at different time-points post-irradiation for DNA DSB in the form of γ-H2AX and Rad51 foci. Using fluorescence microscopy, we examined whether La/SSB and γ-H2AX co-localise and performed proximity ligation assay (PLA) and co-immunoprecipitation to confirm the interaction of these proteins.
We found that the radio-resistant A549 cell line compared to the radio-sensitive H460 cell line showed faster resolution of radiation-induced γ-H2AX foci over time. Conversely, we found more co-localised γ-H2AX and La/SSB foci by PLA in irradiated A549 cells.
The co-localisation of La/SSB with radiation-induced DNA breaks suggests a role of La/SSB in DNA repair, however further experimentation is required to validate this.
铂类化疗和放疗是非小细胞肺癌的标准治疗方法，非小细胞肺癌是全球最常见、最致命的癌症。作为治疗诱导的癌细胞死亡的标志物，我们开发了一种放射诊断成像抗体，该抗体与 La/SSB 结合。La/SSB 是一种必需的、普遍存在的核糖核蛋白，在癌症中过度表达，并且在癌症治疗的耐药性中发挥作用。
在这项研究中，我们研究了肺癌细胞系中辐射诱导的 DNA 双链断裂（DSB），并研究了 La/SSB 是否与这些 DSB 相关。
用不同的 X 射线剂量照射三种肺癌细胞系（A549、H460 和 LL2），或者用 5Gy 的 X 射线照射，然后在照射后的不同时间点检测 γ-H2AX 和 Rad51 焦点形式的 DNA DSB。通过荧光显微镜，我们检查了 La/SSB 和 γ-H2AX 是否共定位，并进行了邻近连接分析（PLA）和共免疫沉淀实验以证实这些蛋白质的相互作用。
我们发现，与放射敏感的 H460 细胞系相比，放射抗性的 A549 细胞系随着时间的推移，辐射诱导的 γ-H2AX 焦点更快地得到解决。相反，我们发现，在照射的 A549 细胞中，通过 PLA 有更多共定位的 γ-H2AX 和 La/SSB 焦点。
La/SSB 与辐射诱导的 DNA 断裂的共定位表明 La/SSB 在 DNA 修复中的作用，但需要进一步的实验来验证这一点。
