Shandong Cancer Hospital Affiliated to Shandong First Medical University Jinan, Shandong
R. Zhang1, W. Yan2, and D. Chen3; 1Shandong University Cancer Center;Department of Radiation Oncology and Shandong Provincial Key Laboratory of Radiation Oncology, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, 2Department of Radiation Oncology and Shandong Provincial Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China, 3Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
Purpose/Objective(s): The main reason for the failure of radiotherapy in non-small cell lung cancer (NSCLC) is the development of radioresistance. Cancer-associated fibroblasts (CAFs) are believed to be a highly active cell population within the tumor stromal barrier and have the ability to survive high-dose radiation. However, further research is needed to understand their role in radiation response. Our objective is to identify protein markers in CAFs that play a role in mediating radiotherapy resistance as tumors progress towards becoming resistant to radiotherapy. Materials/
Methods: This article intends to systematically reveal CAFs as a mediator in the NSCLC tumor microenvironment (TME) to delivery of radioresistance effects by using Single-cell sequencing technology, mRNA sequencing, exosomal microRNA sequencing, subcutaneous C57BL/6 tumor mouse model, molecular biology techniques and clinical tissue samples. The role and molecular mechanism of NSCLC are expected to provide new indicators for predicting the efficacy of radiotherapy and provide new targets for improving the radiosensitivity of NSCLC. Results: Our results show that radioresistant cells are characterized by diminished expression of exosomal miR-370-3p and augmented of miR-301b-3p. These microRNAs directly target FBLN5 and ACSL4, resulting in fibroblast activation. Additionally, the study reveals that fibulin-5, a protein localized in fibroblasts, plays a crucial role in regulating the Src-STAT3-ACSL4 axis through autocrine and paracrine pathways, thereby protecting both fibroblasts and cancer cells from X-Ray irradiation-induced ferroptosis. Consequently, this leads to the formation of a TME characterized by reduced levels of reactive oxygen species (ROS), thereby facilitating the perpetuation of radioresistance. Furthermore, our analysis of clinical tissue samples confirmed a positive correlation between the overexpression of fibulin-5 and the upregulation of fibroblast activation markers and radiotherapy tolerance. Moreover, the single-cell landscape suggests that radioresistant NSCLC cells promote fibroblast activation. Conclusion: These findings highlight the critical intercellular communication between tumor cells and fibroblasts, mediated through tumor-derived exosomes and fibulin-5, serving as key regulators in the formation of a radioresistant niche. Our study suggests that these factors could serve as novel biomarkers for predicting radiotherapy efficacy and as potential therapeutic targets to enhance the radiosensitivity of NSCLC.
