Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China.
Cell Oncol (Dordr). 2024 Aug;47(4):1295-1314. doi: 10.1007/s13402-024-00928-8. Epub 2024 Mar 4.
Esophageal squamous cell carcinoma (ESCC) is an aggressive disease with a poor prognosis, caused by the inactivation of critical cell growth regulators that lead to uncontrolled proliferation and increased malignancy. Although Serine/Threonine Kinase 3 (STK3), also known as Mammalian STE20-like protein kinase 2 (MST2), is a highly conserved kinase of the Hippo pathway, plays a critical role in immunomodulation, organ development, cellular differentiation, and cancer suppression, its phenotype and function in ESCC require further investigation. In this study, we report for the first time on the role of STK3 kinase and its activation condition in ESCC, as well as the mechanism and mediators of kinase activation.
In this study, we investigated the expression and clinical significance of STK3 in ESCC. We first used bioinformatics databases and immunohistochemistry to analyze STK3 expression in the ESCC patient cohort and conducted survival analysis. In vivo, we conducted a tumorigenicity assay using nude mouse models to demonstrate the phenotypes of STK3 kinase. In vitro, we conducted Western blot analysis, qPCR analysis, CO-IP, and immunofluorescence (IF) staining analysis to detect molecule expression, interaction, and distribution. We measured proliferation, migration, and apoptosis abilities in ESCC cells in the experimental groups using CCK-8 and transwell assays, flow cytometry, and EdU staining. We used RNA-seq to identify genes that were differentially expressed in ESCC cells with silenced STK3 or FOXO1. We demonstrated the regulatory relationship of the TP53INP1/P21 gene medicated by the STK3-FOXO1 axis using Western blotting and ChIP in vitro.
We demonstrate high STK3 expression in ESCC tissue and cell lines compared to esophageal epithelium. Cellular ROS induces STK3 autophosphorylation in ESCC cells, resulting in upregulated p-STK3/4. STK3 activation inhibits ESCC cell proliferation and migration by triggering apoptosis and suppressing the cell cycle. STK3 kinase activation phosphorylates FOXO1, promoting nuclear translocation, enhancing transcriptional activity, and upregulating TP53INP1 and P21. We also investigated TP53INP1 and P21's phenotypic effects in ESCC, finding that their knockdown significantly increases tumor proliferation, highlighting their crucial role in ESCC tumorigenesis.
STK3 kinase has a high expression level in ESCC and can be activated by cellular ROS, inhibiting cell proliferation and migration. Additionally, STK3 activation-mediated FOXO1 regulates ESCC cell apoptosis and cell cycle arrest by targeting TP53INP1/P21. Our research underscores the anti-tumor function of STK3 in ESCC and elucidates the mechanism underlying its anti-tumor effect on ESCC.
食管鳞状细胞癌（ESCC）是一种预后不良的侵袭性疾病，其发生是由于关键细胞生长调控因子的失活，导致不受控制的增殖和恶性程度增加。虽然丝氨酸/苏氨酸激酶 3（STK3）又称为哺乳动物 STE20 样蛋白激酶 2（MST2），是 Hippo 通路中高度保守的激酶，在免疫调节、器官发育、细胞分化和癌症抑制中发挥关键作用，但它在 ESCC 中的表型和功能仍需要进一步研究。在本研究中，我们首次报道了 STK3 激酶的作用及其在 ESCC 中的激活条件，以及激酶激活的机制和介质。
在本研究中，我们研究了 STK3 在 ESCC 中的表达和临床意义。我们首先使用生物信息学数据库和免疫组织化学分析方法分析了 ESCC 患者队列中 STK3 的表达，并进行了生存分析。在体内，我们使用裸鼠模型进行了肿瘤发生测定，以证明 STK3 激酶的表型。在体外，我们进行了 Western blot 分析、qPCR 分析、CO-IP 和免疫荧光（IF）染色分析，以检测分子表达、相互作用和分布。我们使用 CCK-8 和 Transwell 测定、流式细胞术和 EdU 染色分析，在实验组中检测 ESCC 细胞的增殖、迁移和凋亡能力。我们使用 RNA-seq 鉴定了沉默 STK3 或 FOXO1 的 ESCC 细胞中差异表达的基因。我们使用体外 Western blot 和 ChIP 证明了由 STK3-FOXO1 轴介导的 TP53INP1/P21 基因的调节关系。
我们证明了与食管上皮相比，ESCC 组织和细胞系中 STK3 的表达较高。细胞内 ROS 诱导 ESCC 细胞中 STK3 自身磷酸化，导致 p-STK3/4 上调。STK3 激活通过触发细胞凋亡和抑制细胞周期来抑制 ESCC 细胞的增殖和迁移。STK3 激酶激活磷酸化 FOXO1，促进核易位，增强转录活性，并上调 TP53INP1 和 P21。我们还研究了 ESCC 中 TP53INP1 和 P21 的表型效应，发现它们的敲低显著增加了肿瘤的增殖，突出了它们在 ESCC 肿瘤发生中的关键作用。
STK3 激酶在 ESCC 中具有高表达水平，并可被细胞内 ROS 激活，抑制细胞增殖和迁移。此外，STK3 激活介导的 FOXO1 通过靶向 TP53INP1/P21 调节 ESCC 细胞凋亡和细胞周期阻滞。我们的研究强调了 STK3 在 ESCC 中的抗肿瘤功能，并阐明了其对 ESCC 的抗肿瘤作用的机制。
