PQA 02 - Lung Cancer/Thoracic Malignancies, Patient Reported Outcomes/QoL/Survivorship, Pediatric Cancer
Presenter(s)
Yang Liu, RT - Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, jinan, shandong provinc
Y. Liu1, Y. Chen2, J. Peng3, and X. Meng4; 1Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, jinan, China, 2Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, 3Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China, 4Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
Purpose/Objective(s):
Radiation-induced lung injury (RILI) is an inevitable complication of thoracic radiotherapy. Activating transcription factor 3 (ATF3), a critical stress-responsive transcription factor of the ATF/CREB family, plays a pivotal role in regulating multiple signaling pathways, including apoptosis, ferroptosis, and cell differentiation. This study aims to investigate the role of ATF3 in the pathogenesis of RILI and to evaluate the therapeutic potential of targeting ATF3 for preventing RILI. Materials/Methods:
A single 20 Gy dose was focally delivered to the left lung of C57BL/6 mice using the Small Animal Radiation Research Platform (SARRP) to establish a radiation-induced lung injury model. Histopathological changes were evaluated by hematoxylin and eosin (H&E) staining, Masson¡¯s trichrome staining, and computed tomography (CT) imaging. Protein expression levels were analyzed via Western blotting. Chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq) were performed to identify downstream targets and associated signaling pathways regulated by ATF3.
Results:
We performed RNA-seq on both normal lung tissue and irradiated lung tissue. The results combined with the analysis of the lung injury database, revealed that ATF3 expression was significantly increased in fibrotic lung tissue. Quantitative reverse transcription PCR (qRT-PCR) and western blot analyses confirmed that ATF3 was indeed upregulated in lung tissues following radiotherapy. To investigate the regulatory role of ATF3 in RILI, we utilized both murine MLE-12 and human BEAS-2B airway epithelial cell lines for analysis. We found that, compared to the control group, ATF3 levels were significantly elevated in cells after radiotherapy. To further confirm the regulatory role of ATF3 in RILI, we established an ATF3 knockout mouse model for RILI and performed H&E staining and Masson staining at the corresponding time points. Combined with CT imaging, we observed that the knockout mice exhibited reduced injury after radiotherapy. These phenotypic findings were supported by western blot protein quantification. We established ATF3 knockdown and overexpression cell models using lentiviral vectors. Following irradiation, ATF3-overexpressing cells exhibited upregulated expression of damage-associated molecules including ¦Á-SMA, fibronectin, and TGF-¦Â. Conversely, ATF3-knockdown cell lines demonstrated downregulation of these fibrosis-related markers. It is stated that ATF3 is a crucial regulatory factor for RILI.
Conclusion: This study is the first to investigate the regulatory role of ATF3 in the process of RILI, providing a theoretical foundation for developing ATF3-targeted radioprotective agents. Future research will focus on elucidating the epigenetic regulatory mechanisms of ATF3 and exploring its translational implications in clinical radiotherapy dose-response relationships.
