College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
BGI-Shenzhen, Shenzhen, 518083, China.
J Transl Med. 2023 Feb 25;21(1):151. doi: 10.1186/s12967-023-03998-8.
Cancer-testis antigens (CTAs) are often expressed in tumor and testicular tissues but not in other normal tissues. To date, there has been no comprehensive study of the expression and clinical significance of CTA genes associated with endometrial cancer (EC) development. Additionally, the clinical relevance, biological role, and molecular mechanisms of the CTA gene TTK protein kinase (TTK) in EC are yet to be fully understood.
Using bioinformatics methods, we comprehensively investigated the genomic, transcriptomic, and epigenetic changes associated with aberrant TTK overexpression in EC samples from the TCGA database. We further investigated the mechanisms of the lower survival associated with TTK dysregulation using single-cell data of EC samples from the GEO database. Cell functional assays were used to confirm the biological roles of TTK in EC cells.
We identified 80 CTA genes that were more abundant in EC than in normal tissues, and high expression of TTK was significantly linked with lower survival in EC patients. Furthermore, ROC analysis revealed that TTK could accurately distinguish stage I EC tissues from benign endometrial samples, suggesting that TTK has the potential to be a biomarker for early EC detection. We found TTK overexpression was more prevalent in EC patients with high-grade, advanced tumors, serous carcinoma, and TP53 alterations. Furthermore, in EC tissue, TTK expression showed a strong positive correlation with EMT-related genes. With single-cell transcriptome data, we identified a proliferative cell subpopulation with high expression of TTK and known epithelial-mesenchymal transition (EMT)-related genes and transcription factors. When proliferative cells were grouped according to TTK expression levels, the overexpressed genes in the TTK group were shown to be functionally involved in the control of chemoresistance. Utilizing shRNA to repress TTK expression in EC cells resulted in substantial decreases in cell proliferation, invasion, EMT, and chemoresistance. Further research identified microRNA-21 (miR-21) as a key downstream regulator of TTK-induced EMT and chemoresistance. Finally, the TTK inhibitor AZ3146 was effective in reducing EC cell growth and invasion and enhancing the apoptosis of EC cells generated by paclitaxel.
Our findings establish the clinical significance of TTK as a new biomarker for EC and an as-yet-unknown carcinogenic function. This present study proposes that the therapeutic targeting of TTK might provide a viable approach for the treatment of EC.
癌睾丸抗原（CTAs）通常在肿瘤和睾丸组织中表达，但在其他正常组织中不表达。迄今为止，尚无关于与子宫内膜癌（EC）发展相关的 CTA 基因表达和临床意义的综合研究。此外，TTK 蛋白激酶（TTK）在 EC 中的临床相关性、生物学作用和分子机制尚未完全阐明。
我们使用生物信息学方法，从 TCGA 数据库中全面研究了与 EC 样本中异常 TTK 过表达相关的基因组、转录组和表观遗传变化。我们进一步使用 GEO 数据库中 EC 样本的单细胞数据研究了 TTK 失调与较低生存率相关的机制。使用细胞功能测定来确认 TTK 在 EC 细胞中的生物学作用。
我们确定了 80 个在 EC 中比在正常组织中更丰富的 CTA 基因，并且 TTK 的高表达与 EC 患者的生存率降低显著相关。此外，ROC 分析表明 TTK 可以准确区分 I 期 EC 组织与良性子宫内膜样本，表明 TTK 有可能成为早期 EC 检测的生物标志物。我们发现 TTK 过表达在具有高级别、晚期肿瘤、浆液性癌和 TP53 改变的 EC 患者中更为普遍。此外，在 EC 组织中，TTK 表达与 EMT 相关基因呈强正相关。使用单细胞转录组数据，我们鉴定了一个具有高 TTK 表达和已知上皮-间充质转化（EMT）相关基因和转录因子的增殖细胞亚群。当根据 TTK 表达水平对增殖细胞进行分组时，TTK 组中过表达的基因在功能上参与了化疗耐药性的控制。利用 shRNA 抑制 EC 细胞中的 TTK 表达导致细胞增殖、侵袭、EMT 和化疗耐药性显著降低。进一步的研究确定 microRNA-21（miR-21）为 TTK 诱导的 EMT 和化疗耐药性的关键下游调节因子。最后，TTK 抑制剂 AZ3146 可有效抑制 EC 细胞生长和侵袭，并增强紫杉醇诱导的 EC 细胞凋亡。
我们的研究结果确立了 TTK 作为 EC 的新生物标志物的临床意义和未知的致癌功能。本研究提出，TTK 的治疗靶向可能为 EC 的治疗提供一种可行的方法。
