3792 - Single-Cell Analysis Identifies SDC1 as a Key Mediator Bridging Extracellular Matrix Stiffness and Radioresistance in Recurrence of Cervical Cancer
Presenter(s)
F. Sun1, J. MA2, M. CAI3, S. Liu4, Z. Hou5, W. Wang5, and W. Xue6; 1The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China, 2The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China, 3Department of Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China, 4Department of Radiation Oncology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi'an, China, 5Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China, 6Department of Radiation Oncology, The First Hospital Affiliated to Xi'an Jiaotong University, Xi'an, China
Purpose/Objective(s): Standard chemoradiotherapy for cervical cancer (CC) is often hindered by local recurrence. Emerging evidence indicates that the crosstalk between extracellular matrix (ECM) components and the matrix stiffness are key drivers of radioresistance. This study aims to elucidate the interplay between matrix stiffness and tumor-stroma crosstalk to identify the mechanisms of the recurrence of CC after chemoradiotherapy, which is essential for developing novel radiosensitization strategies.
Materials/Methods: We integrated scRNA-seq data from GEO database of 6 CC patients (stratified by recurrence after chemoradiotherapy) with ECM stiffness-related gene set and bulk RNA-seq data from TCGA-CESC cohort. Bioinformatic tools (InferCNV, CopyKat, cellchat, and SCENIC) were utilized to dissect the crosstalk between cancer-associated fibroblasts (CAFs) and malignant epithelial cells. We identified a specific ligand-receptor axis that might modulating matrix stiffness and tumor malignancy. To validate the THBS2-SDC1 axis, immunohistochemistry (IHC) was used to characterize the spatial co-localization of THBS2 and SDC1 in CC patients. Moreover, siRNA-mediated knockdown of SDC1 was performed in CC cell lines (HeLa and SiHa), following CCK8 viability assays after radiation.
Results: We found SDC1 as a potential hub gene bridging extracellular matrix stiffness and radioresistance, and its high expression was related with poor prognosis in TCGA cohort. Specifically, cellchat analysis identified THBS2-SDC1 axis as the most significant interaction mediating crosstalk between matrix CAFs (mCAFs) and malignant cells, while THBS2 expression were positively correlated with multiple ECM stiffness-related genes in TCGA-CESC cohort. SCENIC analysis further identified CREB3L1 as a major transcription factor driving THBS2 expression in mCAFs, with its elevated activity in recurrent patients. Notably, SDC1 was significantly enriched in malignant cells of recurrent patients by Ro/e analysis. STRING and Cytoscape network analyses identified SDC1 as a potential hub gene bridging ECM stiffness and radioresistance. To primarily validate the findings, we performed siRNA-mediated knockdown of SDC1 in CC cell lines, which significantly sensitized HeLa cells to 6 Gy radiation comparing with the siNC group (p < 0.05). IHC confirmed the co-localization of stromal THBS2 and tumor-expressed SDC1, providing spatial evidence for this predicted axis.
Conclusion: Integrating single-cell analysis and initial functional validation, we identified THBS2-SDC1 axis as a key driver of CC recurrence after chemoradiotherapy, and SDC1 serves as a hub gene linking extracellular matrix stiffness to treatment failure. We primarily found the relation of SDC1 and radioresistance in CC cell lines. However, the mechanisms underlying the interplay of SDC1, matrix stiffness and radioresistance merit further exploration.