IGF2BP3 functions as an RNA-binding protein (RBP) and plays a role in the posttranscriptional control of mRNA localization, stability, and translation. Its dysregulation is frequently associated with tumorigenesis across various cancer types. Nonetheless, our understanding of how the expression of the IGF2BP3 gene is regulated remains limited. The specific functions and underlying mechanisms of IGF2BP3, as well as the potential benefits of targeting it for therapeutic purposes in bladder cancer, are not yet well comprehended. The mRNA and protein expression were examined by RT-qPCR and western blotting, respectively. The methylation level of CpG sites was detected by Bisulfite sequencing PCR (BSP). The regulation of IGF2BP3 expression by miR-320a-3p was analyzed by luciferase reporter assay. The functional role of IGF2BP3 was determined through proliferation, colony formation, wound healing, invasion assays, and xenograft mouse model. The regulation of HMGB1 by IGF2BP3 was investigated by RNA immunoprecipitation (RIP) and mRNA stability assays. We observed a significant elevation in IGF2BP3 levels within bladder cancer samples, correlating with more advanced stages and grades, as well as an unfavorable prognosis. Subsequent investigations revealed that the upregulation of IGF2BP3 expression is triggered by copy number gain/amplification and promoter hypomethylation in various tumor types, including bladder cancer. Furthermore, miR-320a-3p was identified as another negative regulator in bladder cancer. Functionally, the upregulation of IGF2BP3 expression exacerbated bladder cancer progression, including the proliferation, migration, and invasion of bladder cancer. Conversely, IGF2BP3 silencing produced the opposite effects. Moreover, IGF2BP3 expression positively correlated with inflammation and immune infiltration in bladder cancer. Mechanistically, IGF2BP3 enhanced mRNA stability and promoted the expression of HMGB1 by binding to its mRNA, which is a factor that promotes inflammation and orchestrates tumorigenesis in many cancers. Importantly, pharmacological inhibition of HMGB1 with glycyrrhizin, a specific HMGB1 inhibitor, effectively reversed the cancer-promoting effects of IGF2BP3 overexpression in bladder cancer. Furthermore, the relationship between HMGB1 mRNA and IGF2PB3 is also observed in mammalian embryonic development, with the expression of both genes gradually decreasing as embryonic development progresses. Our present study sheds light on the genetic and epigenetic mechanisms governing IGF2BP3 expression, underscoring the critical involvement of the IGF2BP3-HMGB1 axis in driving bladder cancer progression. Additionally, it advocates for the investigation of inhibiting IGF2BP3-HMGB1 as a viable therapeutic approach for treating bladder cancer.

中文翻译：

---

IGF2BP3 预防膀胱癌和发展中 HMGB1 mRNA 的衰减

IGF2BP3 作为一种 RNA 结合蛋白 (RBP)，在 mRNA 定位、稳定性和翻译的转录后控制中发挥作用。它的失调通常与各种癌症类型的肿瘤发生有关。尽管如此，我们对 IGF2BP3 基因表达如何调控的理解仍然有限。IGF2BP3 的具体功能和潜在机制，以及将其用于治疗膀胱癌的潜在益处，目前尚未得到很好的理解。分别通过RT-qPCR和蛋白质印迹检查mRNA和蛋白表达。通过亚硫酸氢盐测序PCR（BSP）检测CpG位点的甲基化水平。通过荧光素酶报告基因测定分析 miR-320a-3p 对 IGF2BP3 表达的调节。IGF2BP3 的功能作用通过增殖、集落形成、伤口愈合、侵袭测定和异种移植小鼠模型来确定。通过 RNA 免疫沉淀 (RIP) 和 mRNA 稳定性测定研究了 IGF2BP3 对 HMGB1 的调节。我们观察到膀胱癌样本中 IGF2BP3 水平显着升高，这与更晚期的分期和分级以及不良预后相关。随后的研究表明，IGF2BP3 表达的上调是由多种肿瘤类型（包括膀胱癌）中的拷贝数增加/扩增和启动子低甲基化触发的。此外，miR-320a-3p 被确定为膀胱癌的另一个负调节因子。从功能上讲，IGF2BP3表达的上调加剧了膀胱癌的进展，包括膀胱癌的增殖、迁移和侵袭。相反，IGF2BP3 沉默产生相反的效果。此外，IGF2BP3的表达与膀胱癌的炎症和免疫浸润呈正相关。从机制上讲，IGF2BP3 通过与其 mRNA 结合增强 mRNA 稳定性并促进 HMGB1 的表达，HMGB1 是许多癌症中促进炎症和协调肿瘤发生的因素。重要的是，用甘草甜素（一种特定的 HMGB1 抑制剂）对 HMGB1 进行药理学抑制，可有效逆转膀胱癌中 IGF2BP3 过度表达的促癌作用。此外，在哺乳动物胚胎发育中也观察到HMGB1 mRNA和IGF2PB3之间的关系，随着胚胎发育的进展，这两个基因的表达逐渐下降。我们目前的研究揭示了控制 IGF2BP3 表达的遗传和表观遗传机制，强调了 IGF2BP3-HMGB1 轴在驱动膀胱癌进展中的关键参与。此外，它还主张研究抑制 IGF2BP3-HMGB1 作为治疗膀胱癌的可行治疗方法。