本研究旨在通过数据挖掘、临床样本分析和基础实验来阐明Fingolimod对头颈部鳞状细胞癌（HNSC）的治疗效果，并初步探索其作用机制。通过SwissTargetPrediction和The Cancer Genome Atlas（TCGA）数据库获取了肿瘤组织中Fingolimod的标准化丰度评分（NES）。基于癌症药物敏感性基因组学（GDSC）数据库验证了Fingolimod对HNSC的IC50（50%抑制浓度）。将SCC9细胞体外培养以应用Fingolimod。细胞增殖通过细胞计数试剂盒-8（CCK-8）测定。基因的表达水平通过逆转录-聚合酶链式反应（RT-PCR）进行测定。采用WebGestalt分析了Fingolimod在HNSC中的分子调控机制。通过Western印迹实验证明了Fingolimod对细胞周期蛋白的表达。通过TCGA数据库筛选出Fingolimod对HNSC的关键靶向基因，并在临床样本中进行验证。基因集富集分析（GSEA）显示HNSC的NES得分最高（NES=1.53，P<0.05）。GDSC显示Fingolimod在SSC9细胞中的IC50最低。细胞活力通过CCK8检测得到的IC50为4.34μmol/L，而RT-PCR显示添加Fingolimod后，增殖相关基因Ki-67的表达显著受到抑制（P<0.05）。Kyoto Encyclopedia of Genes and Genomes（KEGG）富集分析揭示Fingolimod的靶向基因主要富集于细胞周期相关途径。Western印迹结果显示，添加Fingolimod后，SSC9细胞的细胞周期蛋白表达显著下调（P<0.05）。TCGA分析显示PLK1是Fingolimod治疗HNSC的关键靶向基因。RT-PCR显示过表达PLK1后，SCC9的活性显著增加，增加了增殖和抗凋亡能力（P<0.05），并在添加Fingolimod后，Ki-67和Bcl-2的表达显著受到抑制。Fingolimod可以促进SCC9细胞在G0/G1期的阻滞，而PLK1是治疗HNSC的关键靶向基因。Fingolimod可以抑制PLK1过表达引起的细胞增殖。

This study aimed to clarify the therapeutic effect of Fingolimod on head and neck squamous cell carcinoma (HNSC) and initially explore its mechanism through data mining, clinical sample analysis and basic experiments. The normalized Enrichment Score (NES) of Fingolimod in tumor tissues was obtained by SwissTargetPrediction and The Cancer Genome Atlas (TCGA) database. IC50 (50% inhibitory concentration) of Fingolimod for HNSC was verified based on the Genomics of Drug Sensitivity in Cancer (GDSC) database. SCC9 cells were cultured in vitro for the application of Fingolimod. Cell proliferation was determined by the Cell Counting Kit-8 (CCK-8). The expression levels of genes were determined by reverse transcription-polymerase chain reaction (RT-PCR). The molecular regulatory mechanism of Fingolimod acting on HNSC was analyzed with WebGestalt. Cyclin expression was determined by Western blot assay. The key targeted genes for Fingolimod against HNSC were screened with the TCGA database and verified in clinical samples. Gene Set Enrichment Analysis (GSEA) showed the highest NES score in HNSC (NES=1.53, P<0.05). GDSC showed the lowest IC50 in Fingolimod SSC9 cells. IC50 calculated by the cell activity detected by CCK8 was 4.34 μmol/L, and RT-PCR showed significantly suppressed expression of proliferation-related gene Ki-67 after adding Fingolimod (P<0.05). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the targeted genes for Fingolimod were mainly enriched in cell cycle-related pathways. Western blot showed significantly decreased cyclin expression in SSC9 cells after the treatment with Fingolimod (P<0.05). TCGA analysis revealed that PLK1 is a key targeted gene for Fingolimod in the treatment of HNSC. RT-PCR showed the significantly increased activity of SCC9 after over-expressing PLK1, and the increased proliferation and anti-apoptosis abilities (P<0.05), as well as the significantly inhibited expression of Ki-67 and Bcl-2 after adding Fingolimod. Fingolimod can promote the arrest in G0/G1 of SCC9 cells, and PLK1 is a key targeted gene for the treatment of HNSC. Fingolimod can inhibit cell proliferation caused by PLK1 over-expression.