Department of Pediatric Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, P.R. China.
Department of Pathology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, P.R. China.
World Neurosurg. 2022 Aug;164:e99-e112. doi: 10.1016/j.wneu.2022.04.009. Epub 2022 Apr 8.
Neuroblastoma is one of the most common extracranial solid tumors in children. The forkhead transcription factor FOXO3a has been implicated in the progression of a variety of human diseases. Here, we aim to identify the effects of FOXO3a on the malignancy of neuroblastoma.
Bioinformatics analysis was employed to identify differentially expressed genes related to neuroblastoma and the downstream regulator of FOXO3a. FOXO3a expression was examined in SH-SY5Y neuroblastoma cells. Interactions between FOXO3a and microRNA-21 (miR-21) were then identified using bioinformatics analysis and dual-luciferase reporter assay. After ectopic expression and depletion experiments in SH-SY5Y cells, cell malignant phenotypes were assessed by cell counting kit-8 and Transwell assays. FOXO3a-overexpressing neuroblastoma cells were xenografted into nude mice to validate the role of FOXO3a in tumor growth.
Downregulated expression of FOXO3a was observed in neuroblastoma cells, with a negative correlation between FOXO3a and miR-21 expression. FOXO3a bound to the promoter region of miR-21 to downregulate its expression, resulting in inhibition of SH-SY5Y cell malignant phenotypes. Additionally, miR-21 targeted SPRY2 by binding to the 3'UTR of the mRNA encoding SPRY2, activating the extracellular signal-regulated kinase (ERK) pathway. FOXO3a disrupted the binding of miR-21 to SPRY2 and inactivated ERK to suppress the malignant phenotypes of SH-SY5Y cells as well as tumor growth in vivo.
In conclusion, FOXO3a may inhibit the progression of neuroblastoma by suppressing the miR-21 expression and facilitating SPRY2-dependent ERK pathway inactivation.
神经母细胞瘤是儿童最常见的颅外实体瘤之一。叉头转录因子 FOXO3a 被认为与多种人类疾病的进展有关。在这里，我们旨在确定 FOXO3a 对神经母细胞瘤恶性程度的影响。
采用生物信息学分析方法鉴定与神经母细胞瘤相关的差异表达基因及其下游 FOXO3a 调控因子。检测 SH-SY5Y 神经母细胞瘤细胞中 FOXO3a 的表达。利用生物信息学分析和双荧光素酶报告基因检测鉴定 FOXO3a 与 microRNA-21 (miR-21) 之间的相互作用。在 SH-SY5Y 细胞中外源表达和敲低实验后，通过细胞计数试剂盒-8 和 Transwell 实验评估细胞恶性表型。将 FOXO3a 过表达的神经母细胞瘤细胞异种移植到裸鼠体内，验证 FOXO3a 在肿瘤生长中的作用。
在神经母细胞瘤细胞中观察到 FOXO3a 表达下调，FOXO3a 与 miR-21 表达呈负相关。FOXO3a 结合到 miR-21 启动子区域，下调其表达，从而抑制 SH-SY5Y 细胞恶性表型。此外，miR-21 通过结合 SPRY2 mRNA 的 3'UTR 靶向 SPRY2，激活细胞外信号调节激酶（ERK）通路。FOXO3a 破坏了 miR-21 与 SPRY2 的结合，使 ERK 失活，从而抑制 SH-SY5Y 细胞的恶性表型以及体内肿瘤的生长。
总之，FOXO3a 可能通过抑制 miR-21 的表达并促进 SPRY2 依赖性 ERK 通路失活来抑制神经母细胞瘤的进展。
