Experimental study of early evaluation of radiosensitivity in mouse models of lung cancers using 89Zr-anti-γH2AX-TAT PET imaging.

Background: Early evaluation of radiation sensitivity in lung cancer patients can facilitate the transition to personalized treatment strategies. To this end, we assessed the capability of ⁸⁹Zr-anti-γH2AX-TAT microPET imaging in determining the radiosensitivity of lung cancer xenograft models. We prepared and conducted quality control on ⁸⁹Zr-anti-γH2AX-TAT. The radiosensitivity of human non-small cell lung cancer cells (H460) and adenocarcinoma cells (A549) was analyzed through clonogenic survival experiments. Additionally, the role of γH2AX as a biomarker for radiosensitivity was validated by quantifying γH2AX foci via fluorescence staining. Subsequently, the H460 and A549 xenograft mouse models were subjected to irradiation, followed by ⁸⁹Zr-anti-γH2AX-TAT microPET imaging. Concurrently, we performed immunofluorescence staining for γH2AX in tumor tissues to establish a correlation between the uptake of ⁸⁹Zr-anti-γH2AX-TAT and γH2AX expression.

Results: The surviving fraction 2 Gy (SF2) values of H460 and A549 indicating that A549 adenocarcinoma has higher radiosensitivity. The cell immunofluorescence experiment showed that the repair of γH2AX foci in H460 cells after irradiation was significantly higher than that in A549 cells, which also confirmed that A549 has higher radiosensitivity. The microPET imaging results showed the uptake of ⁸⁹Zr-anti-γH2AX-TAT in the tumor of the A549 models after radiotherapy was higher than H460 models. The immunofluorescence staining of tumor tissue confirmed that the expression level of γH2AX was higher and the correlation with microPET imaging uptake was good.

Conclusion: ⁸⁹Zr-anti-γH2AX-TAT allows PET imaging of radiosensitivity in lung cancer xenograft models, and is expected to become an early evaluation method for lung cancer radiosensitivity.