Revealing NAPSA's role in ccRCC: Insights from single-cell RNA sequencing

Clear cell renal cell carcinoma (ccRCC) is aggressive and heterogeneous, resulting in poor prognosis due to frequent metastasis. Napsin A, an aspartic proteinase encoded by the NAPSA gene, is involved in protein processing and is expressed in the kidney and lung, but its function is not well understood. Studying ccRCC's molecular characteristics, including Napsin A, is vital for enhancing diagnostics and treatment.

Single-cell RNA sequencing data from the GEO database (GSE210042) were analyzed, including seven tumor and two normal samples. The Seurat package was used for data preprocessing, clustering, and visualization. Differential expression and enrichment analyses were conducted between tumor and normal cells, and cell-to-cell communication was assessed between NAPSA + and NAPSA- cells. The correlation between NAPSA expression and EMT score was analyzed using TCGA-KIRC data. In vitro experiments involved transfecting OS-RC-2 and Caki-1 ccRCC cell lines with siRNA targeting NAPSA. Effect on the cellular EMT process induced by TGF-β1 was assessed by immunofluorescence staining.

NAPSA was primarily expressed in podocytes and ccRCC epithelial cells, with significantly reduced levels in tumor tissues associated with poor prognosis. NAPSA downregulation may influence various biological pathways and enhance communication with tumor-associated macrophages and mast cells. Silencing NAPSA increased TGF-β1-induced epithelial-mesenchymal transition (EMT).

The study highlights NAPSA's expression characteristics and potential role in ccRCC, suggesting it may serve as a biomarker. Further research is needed to elucidate NAPSA's mechanisms and explore its applications in precision medicine.