The Disulfidptosis-Mediated Intercellular Communication in the Tumor Microenvironment Contributes to the Progression of Osteosarcoma and Immunotherapy

Abstract

Background: Disulfidptosis, a recently identified form of cell death triggered by excessive cysteine accumulation and subsequent disulfide stress, has emerged as a novel mechanism of cell death. Despite its significance, the role of disulfidptosis in the tumor microenvironment (TME) remains poorly understood.
 Methods: In this study, we employed single-cell RNA sequencing data from 100,987 cells of 11 osteosarcoma (OS) patients. Using the non-negative matrix factorization (NMF) algorithm, we performed dimensionality reduction analysis to identify distinct subtypes characterized by 14 disulfidptosis-related genes across major cell types within the TME. Subsequently, we assessed the prognosis and immunotherapy response associated with each disulfidptosis-related subtype, leveraging publicly available databases comprising osteosarcoma data and immunotherapy cohorts.
 Results: We identified distinct subtypes within tumor-associated fibroblasts, tumor-infiltrating lymphocytes, and macrophages, which we named and annotated based on their characteristic genes. Furthermore, we observed a close association between disulfidptosis-related genes and key biological features of immune cells within the TME, elucidating inferred pseudotime trajectories. Notably, integrating bulk-seq data of osteosarcoma patients, we observed significant differences in overall survival rates among the disulfidptosis-related subtypes. Particularly, the disulfidptosis-related subtype within tumor-associated fibroblasts exhibited superior discriminatory ability in predicting the response of patients undergoing immunotherapy, surpassing other cell subtypes. Our cell-cell communication analysis highlighted extensive and specific interactions between disulfidptosis-related subtypes and osteosarcoma cells. Furthermore, we confirmed the histological localization of the CAPZB+CAF subtype within osteosarcoma tissue and osteoclastoma using immunofluorescence (IF) techniques.
 Conclusions: Collectively, our study sheds light on the intercellular communication facilitated by disulfidptosis in the TME, underscoring its involvement in the biological functions and immunotherapy response of osteosarcoma.