Single-cell mitophagy patterns dictate intercellular crosstalk in the tumor microenvironment to promote osteosarcoma progression.

BACKGROUND

Osteosarcoma (OS) is a highly aggressive primary bone malignancy in adolescents, with poor prognosis due to limited diagnostic and therapeutic strategies. Mitochondrial dysfunction is a hallmark of cancer, and mitophagy, the selective clearance of damaged mitochondria, critically maintains cellular homeostasis. However, the specific role of mitophagy in shaping the OS tumor microenvironment (TME) at single-cell resolution remains poorly understood. This study aims to systematically characterize mitophagy patterns within the OS TME and investigate their impact on intercellular communication, tumor progression, and patient prognosis.

METHODS

We analyzed single-cell RNA sequencing data from OS samples using non-negative matrix factorization to cluster cells based on mitophagy-related genes. We characterized distinct mitophagy-associated subtypes of TME cells. Pseudotime trajectory, cell-cell communication), gene regulatory network, and functional enrichment analyses were performed. Prognostic significance was evaluated using GSVA and Cox regression in bulk RNA-seq cohort. Immunotherapy response was predicted using the TIDE algorithm.

RESULTS

We identified diverse mitophagy-activated cellular subtypes within the TME. Mitophagy-active CAFs and macrophages exhibited enhanced angiogenic signaling to endothelial cells. Mitophagy-associated CD8+ T cells displayed marked exhaustion features, while macrophages showed metabolic reprogramming. Clinically, higher infiltration of these mitophagy-related subtypes was consistently associated with poorer overall survival. TIDE analysis indicated that mitophagy patterns potentially correlate with immune checkpoint blockade response.

CONCLUSIONS

Our findings reveal that mitophagy drives complex intercellular crosstalk in the OS TME, promoting angiogenesis and immunosuppression. Mitophagy-related signatures serve as robust prognostic biomarkers. These insights suggest that targeted inhibition of mitophagy, rather than activation, represents a promising therapeutic strategy, providing a novel framework for improving OS patient outcomes.