肝细胞肝癌（HCC）是目前最致命的恶性肿瘤之一。根据先前的研究，19 号染色体miRNA簇（C19MC）与肝癌患者的肿瘤高负荷和不良预后相关。目前的研究旨在探讨miR-516a-3p 在HCC 中的作用。miR-516a-3p 是一种由C19MC 4 个致癌前体miRNA（即mir-516a-1、mir-516a-2、mir-516b-1 和mir-516b-2）所共同剪接而成的相同的成熟体miRNA。在肝癌队列中，与瘤旁组织相比，miR-516a-3p 在肝癌组织中显著高表达。肿瘤miR-516a-3p 的高表达与肝癌高肿瘤负荷相关，可以区分高HCC复发率和死亡率，并独立预测肝癌的不良预后。进一步通过体外实验发现miR-516a-3p 增强了肝癌细胞的增殖、迁移和侵袭性，并通过体内实验验证miR-516a-3p 促进了肿瘤的增殖和远处转移能力。在肝癌细胞中，miR-516a-3p 可以通过外泌体进行递送，并增加受体肝癌细胞的致癌活性。此外，为探索miR-516a-3p 致癌的潜在机制，本研究进行了全面的转录组学、蛋白质组学和代谢组学分析。多组学DIABLO分析显示，蛋白质组学和代谢组学数据之间具有密切的相关性和较强的聚类一致性。进一步证实了6 种基因的mRNA（即LMBR1、CHST9、RBM3、SLC7A6、PTGFRN和NOL12）是miR-516a-3p 的直接靶点，并在miR-516a-3p 介导的代谢调节中发挥核心作用。综合多组学和共富集途径分析表明，miR-516a-3p 可以调节肝癌细胞的代谢途径，特别是嘌呤代谢和嘧啶代谢。总之，本研究发现，miR-516a-3p 可以通过调节细胞代谢和外泌体递送系统
影响相邻细胞，促进肝癌细胞的肿瘤恶性进展。因此，miR-516a-3p可作为肝癌治疗的新分子靶点。

Hepatocellular carcinoma (HCC) remains one of the most lethal malignancies. We previously demonstrated that the chromosome 19 microRNA cluster (C19MC) was associated with tumor burden and prognosis in patients with HCC. In the current study, we aim to explore the role of miR-516a-3p—an identical mature microRNA (miRNA) co-spliced by four oncogenic pre-miRNAs of C19MC (i.e., mir-516a-1, mir-516a-2, mir-516b-1, and mir-516b-2)—in HCC. In our cohort of HCC patients, miR-516a-3p was highly expressed in HCC tissues in comparison with adjacent non-tumor tissues. High expression of tumor miR-516a-3p significantly correlated with advanced tumor stages, distinguished high HCC recurrence and mortality, and independently predicted poor prognosis. We further found that miR-516a-3p enhanced the proliferation, migration, and invasiveness of HCC cells in vitro and promoted tumor growth and metastasis in vivo. Among cancer cells, miR-516a-3p could be delivered via exosomes or extracellular vesicles and increased the oncogenic activity of recipient cells. Moreover, we performed comprehensive transcriptomics, proteomics, and metabolomics analysis on the potential mechanism underlying miR-516a-3p-promoted oncogenicity. MixOmic DIABLO analysis showed a close correlation and strong cluster consistency between the proteomics and metabolomics datasets. We further confirmed six proteins (i.e., LMBR1, CHST9, RBM3, SLC7A6, PTGFRN, and NOL12) as the direct targets of miR-516a-3p and as central players in miR-516a-3p-mediated metabolism regulation. The integrated multi-omics and co-enriched pathway analysis showed that miR-516a-3p regulates the metabolic pathways of HCC cells, particularly purine and pyrimidine metabolism. In conclusion, our findings suggest that miR-516a-3p promotes malignant behaviors in HCC cells by regulating cellular metabolism and affecting neighboring cells via the exosome delivery system. Thus, we suggest miR-516a-3p as a novel molecular target for HCC therapy.