SLC17A9 as a prognostic biomarker correlated with immune infiltrates in human non-small cell lung cancer

Am J Cancer Res. 2023 Sep 15;13(9):3963-3982. eCollection 2023.

Abstract

The vesicular nucleotide transporter (SLC17A9) has been overexpressed in various cancers. Nonetheless, little is known about its influence on non-small cell lung cancer (NSCLC), including human lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). Integrative bioinformatics analysis was performed to investigate the prognostic significance and underlying mechanisms of SLC17A9 in patients with NSCLC. Here, we found that SLC17A9 up-regulation was significantly correlated with overall survival in LUAD and LUSC (P < 0.05). Gene set enrichment analysis and protein-protein interaction results revealed that SLC17A9 up-regulation was linked to metabolic process, the hallmark of MYC targets, DNA repair, coagulation and complement. SLC17A9 expression was negatively associated with overall survival and positively related to most LUSC immune cells and immunoinhibitor (20/23), particularly immuno A2aR, PD-1, and CTLA-4 (P < 0.001). High SLC17A9 was associated with infiltrating levels of B cells, CD4+ T cells, M1 macrophages, and T cell exhaustion checkpoints such as PD-1, CTLA4, and LAG3 in LUAD. Moreover, Real-time PCR, MTS assay, EdU assay, ATP production assays and cell cycle analysis were performed to validate SLC17A9 knockdown in LUAD cells. SLC17A9 knockdown significantly inhibited cell proliferation and ATP levels by affecting P2X1, Cytochrome C, and STAT3 expression in lung cancer cells. In conclusion, the present study suggested that SLC17A9 could potentially serve as a prognostic biomarker and correlated with immune infiltrates in LUAD and LUSC.

Keywords: SLC17A9; immune infiltrates; lung adenocarcinoma; lung squamous cell carcinoma; prognosis.