Core Viewpoint - The study highlights the role of metabolic reprogramming in promoting immune suppression in hepatocellular carcinoma (HCC), which is crucial for developing targeted and effective anti-tumor strategies [2][3]. Group 1: Research Findings - The research integrates multi-omics data, including metabolomics, transcriptomics, and single-cell sequencing, to elucidate how tumor cells produce and actively export N1-acetylspermidine (N1-Ac-Spd), leading to immune suppression [3][4]. - N1-Ac-Spd accumulates in HCC tissues and increases in paired plasma compared to non-tumor liver tissues, promoting tumor progression and weakening the efficacy of immune checkpoint blockade (ICB) therapy in preclinical models [4][6]. - Inflammatory macrophages enhance the expression of SAT1 in HCC cells, which increases the export of N1-Ac-Spd through the polyamine transporter SLC3A2, creating an immunosuppressive tumor microenvironment [5][6]. Group 2: Mechanistic Insights - N1-Ac-Spd activates SRC signaling in a charge-dependent manner, leading to the polarization of CCL1+ macrophages and recruitment of regulatory T cells, which diminishes the effectiveness of ICB therapy [5][6]. - Blocking the synthesis of N1-Ac-Spd or targeting SLC3A2, SAT1, or CCL1 can significantly enhance the anti-tumor effects of ICB therapy [5][6]. Group 3: Implications for Treatment - The findings reveal mechanisms by which metabolic reprogramming fosters an immunosuppressive tumor microenvironment, providing theoretical foundations and potential intervention targets for enhancing HCC treatment [6][9].