Natural compound 5,7,8‑trimethoxyflavone mitigates radiation‑induced lung injury by suppressing EMT and PI3K/Akt pathway.

Radiation‑induced lung injury (RILI) remains a dose‑limiting and life‑threatening complication of thoracic radiotherapy. The present study aimed to evaluate the therapeutic efficacy and mechanism of the naturally extracted flavonoid, 5,7,8‑trimethoxyflavone (HY‑N7656), in inhibiting RILI. Lung injury in mice was evaluated using micro‑computed tomography, histopathological analysis, enzyme‑linked immunosorbent assay and western blotting. Network pharmacology was conducted to predict the potential therapeutic targets and signaling pathways of HY‑N7656 in RILI. Cell Counting Kit‑8, wound healing, immunofluorescence, reverse transcription‑quantitative (RT‑q) PCR and protein expression analyses were carried out in vitro using TGF‑β‑stimulated A549 cells to evaluate epithelial‑mesenchymal transition (EMT) and signaling activity. Results of the present study revealed that HY‑N7656 markedly alleviated pulmonary inflammation and fibrosis in irradiated mice, leading to a reduction in α‑smooth muscle actin expression. In addition, EMT was effectively reversed following treatment with HY‑N7656 in A549 alveolar epithelial cells treated with TGF‑β, accompanied by restoration of E‑cadherin expression and downregulation of mesenchymal markers, such as N‑cadherin and vimentin. Network pharmacology analysis and molecular docking validation identified the PI3K/Akt pathway as a central target, which was subsequently confirmed via western blot analysis. Moreover, results of the present study demonstrated that HY‑N7656 inhibited radiation‑induced activation of PI3K and Akt. To the best of the authors' knowledge, the present study was the first to demonstrate that HY‑N7656 modulates the PI3K/Akt signaling pathway to suppress the progression of EMT in RILI, establishing HY‑N7656 as a multi‑target inhibitor of RILI. These findings present a potential strategy to enhance the safety of radiotherapy, warranting further preclinical and clinical evaluation.