Abstract:

Background and purpose: Patients with prostate cancer (PCa) have consistently shown suboptimal responses to immunotherapy, which may be closely related to the immunosuppressive state of the PCa tumor microenvironment. MYC, a key transcription factor in cancer cells, is involved in cell proliferation, differentiation, apoptosis and immune surveillance by regulating the expression of intracellular genes. This study aimed to elucidate the mechanisms through which MYC fosters an immunosuppressive state within the PCa tumor microenvironment and to delineate its functional impact on PCa cells. Methods: We performed clustering and annotation of single-cell RNA sequencing (scRNA-seq) data from PCa, and conducted subcluster analyses for tumor cells, T cells, and macrophages respectively. The expression changes of MYC and CD47 across tumor subtype were analyzed, and the expression variations of signal regulatory protein alpha (SIRPα) among macrophage subtype were assessed. Furthermore, we divided the PCa transcriptomic dataset samples into high- and low-MYC expression groups based on MYC expression levels, and performed differential expression analysis and enrichment analysis for each group. The functional role of MYC in PCa cells was validated using chromatin immunoprecipitation-quantitative polymerase chain reaction (ChIP-qPCR) and experimental analyses. Furthermore, animal experiments (reviewed and approved by the ethics committee of the First Affiliated Hospital of Henan University of Science and Technology, approval number: D-2025-B015) were conducted to further validate the relationship between MYC and CD47. Finally, we analyzed and validated the whey acidic protein four-disulfide core domain 2 (WFDC2)⁺ tumor subtype using transcriptomic data from PCa. Results: Through the analysis of scRNA-seq data from PCa, a total of 32,977 cells were identified, and 7 distinct cell types were annotated. The tumor cells were further divided into 10 tumor cell subtypes, among which the WFDC2⁺ tumor cell subtype exhibited more intensive cellular communication with CD8⁺ T cells and macrophages within the PCa tumor microenvironment. MYC and CD47 exhibited high expression levels during the middle-to-late stages of differentiation in PCa cells, whereas SIRPα maintained high expression throughout the macrophage differentiation trajectory. Enrichment analysis revealed that the WFDC2⁺ tumor cell subtype was primarily enriched in signaling pathways such as transforming growth factor-β (TGF-β) and Wnt/β-catenin. ChIP-qPCR confirmed the regulatory relationship between MYC and CD47 expression. Additionally, it was found that MYC knockdown significantly inhibited the proliferation and invasion abilities of PCa cells, while overexpression of CD47 could reverse this effect. Animal experiment results confirmed an positive correlation between MYC and CD47 protein expression. Furthermore, Tumor Immune Dysfunction and Exclusion (TIDE) and Estimate analyses indicated that patients in the low-expression group of the WFDC2⁺ tumor cell subtype exhibited a potentially better response to immunotherapy compared to those in the high-expression group. Conclusion: The findings of this study elucidate the role of MYC in the PCa tumor immune microenvironment. Specifically, MYC promotes the proliferation and migration of PCa cells by regulating the expression of CD47. These insights provide novel perspectives for the treatment of PCa patients.

Key words: Prostate cancer, MYC, CD47, Immunotherapy, Tumor microenvironment