FOXM1 因子在肝细胞癌中的全面临床病理意义及潜在转录机制。

BACKGROUND: The Forkhead box M1 factor (FOXM1) is a crucial activator for cancer cell proliferation. While FOXM1 has been shown to promote hepatocellular carcinoma (HCC) progression, its transcriptional mechanisms remain incompletely understood. METHODS: We performed an in-house tissue microarray on 313 HCC and 37 non-HCC tissue samples, followed by immunohistochemical staining. Gene chips and high throughput sequencing data were used to assess FOXM1 expression and prognosis. To identify candidate targets of FOXM1, we comprehensively reanalyzed 41 chromatin immunoprecipitation followed by sequencing (ChIP-seq) data sets. We predicted FOXM1 transcriptional targets in HCC by intersecting candidate FOXM1 targets with HCC overexpressed genes and FOXM1 correlation genes. Enrichment analysis was employed to address the potential mechanisms of FOXM1 underlying HCC. Finally, single-cell RNA sequencing analysis was performed to confirm the transcriptional activity of FOXM1 on its predicted targets. RESULTS: This study, based on 4235 HCC tissue samples and 3461 non-HCC tissue samples, confirmed the upregulation of FOXM1 in HCC at mRNA and protein levels (standardized mean difference = 1.70 [1.42, 1.98]), making it the largest multi-centered study to do so. Among HCC patients, FOXM1 was increased in Asian and advanced subgroups, and high expression of FOXM1 had a strong ability to differentiate HCC tissue from non-HCC tissue (area under the curve = 0.94, sensitivity = 88.72%, specificity = 87.24%). FOXM1 was also shown to be an independent exposure risk factor for HCC, with a pooled hazard ratio of 2.00 [1.77, 2.26]. The predicted transcriptional targets of FOXM1 in HCC were predominantly enriched in nuclear division, chromosomal region, and catalytic activity acting on DNA. A gene cluster encoding nine transcriptional factors was predicted to be positively regulated by FOXM1, promoting the cell cycle signaling pathway in HCC. Finally, the transcriptional activity of FOXM1 and its targets was supported by single-cell analysis of HCC cells. CONCLUSIONS: This study not only confirmed the upregulation of FOXM1 in HCC but also identified it as an independent risk factor. Moreover, our findings enriched our understanding of the complex transcriptional mechanisms underlying HCC pathogenesis, with FOXM1 potentially promoting HCC progression by activating other transcription factors within the cell cycle pathway.

背景：叉头框 M1 因子（FOXM1）是癌细胞增殖的关键激活因子。虽然 FOXM1 已被证明促进肝细胞癌（HCC）的进展，但它的转录机制仍不完全清楚。

方法：我们对 313 例 HCC 和 37 例非 HCC 组织样本进行了内部组织微阵列分析，随后进行了免疫组织化学染色。使用基因芯片和高通量测序数据评估 FOXM1 的表达和预后。为了确定 FOXM1 的候选靶标，我们全面重新分析了 41 个染色质免疫沉淀测序（ChIP-seq）数据集。我们通过将候选 FOXM1 靶标与 HCC 过表达基因和 FOXM1 相关基因进行交集，预测 HCC 中的 FOXM1 转录靶标。富集分析用于解决 HCC 中 FOXM1 潜在的潜在机制。最后，进行单细胞 RNA 测序分析以确认 FOXM1 在其预测靶标上的转录活性。

结果：这项基于 4235 例 HCC 组织样本和 3461 例非 HCC 组织样本的研究，在 mRNA 和蛋白质水平上证实了 HCC 中 FOXM1 的上调（标准化均数差=1.70[1.42,1.98]），这是最大的多中心研究。在 HCC 患者中，FOXM1 在亚洲和晚期亚组中增加，FOXM1 高表达具有很强的区分 HCC 组织和非 HCC 组织的能力（曲线下面积=0.94，灵敏度=88.72%，特异性=87.24%）。FOXM1 也是 HCC 的独立暴露风险因素，合并危险比为 2.00[1.77,2.26]。在 HCC 中，FOXM1 的预测转录靶标主要富集在核分裂、染色体区域和作用于 DNA 的催化活性。预测有一个编码九个转录因子的基因簇受 FOXM1 正向调控，促进 HCC 中的细胞周期信号通路。最后，通过 HCC 细胞的单细胞分析支持了 FOXM1 及其靶标的转录活性。

结论：这项研究不仅证实了 HCC 中 FOXM1 的上调，而且还将其确定为一个独立的风险因素。此外，我们的研究结果丰富了我们对 HCC 发病机制中复杂转录机制的理解，FOXM1 可能通过激活细胞周期途径中的其他转录因子来促进 HCC 的进展。