Research Unit of Microscopic and Ultrastructural Anatomy, Department of Medicine, Campus Bio-Medico University, Rome, Italy.
Predictive Molecular Diagnostic Unit, Department of Pathology, Campus Bio-Medico University Hospital, Rome, Italy.
Oncogene. 2021 Jun;40(23):4033-4049. doi: 10.1038/s41388-021-01824-3. Epub 2021 May 20.
Intrahepatic cholangiocarcinoma (iCCA) is a rare malignancy of the intrahepatic biliary tract with a very poor prognosis. Although some clinicopathological parameters can be prognostic factors for iCCA, the molecular prognostic markers and potential mechanisms of iCCA have not been well investigated. Here, we report that the Fragile X mental retardation protein (FMRP), a RNA binding protein functionally absent in patients with the Fragile X syndrome (FXS) and also involved in several types of cancers, is overexpressed in human iCCA and its expression is significantly increased in iCCA metastatic tissues. The silencing of FMRP in metastatic iCCA cell lines affects cell migration and invasion, suggesting a role of FMRP in iCCA progression. Moreover, we show evidence that FMRP is localized at the invasive front of human iCCA neoplastic nests and in pseudopodia and invadopodia protrusions of migrating and invading iCCA cancer cells. Here FMRP binds several mRNAs encoding key proteins involved in the formation and/or function of these protrusions. In particular, we find that FMRP binds to and regulates the expression of Cortactin, a critical regulator of invadopodia formation. Altogether, our findings suggest that FMRP could promote cell invasiveness modulating membrane plasticity and invadopodia formation at the leading edges of invading iCCA cells.
肝内胆管癌(iCCA)是一种罕见的肝内胆管恶性肿瘤,预后极差。虽然一些临床病理参数可以作为 iCCA 的预后因素,但 iCCA 的分子预后标志物和潜在机制尚未得到充分研究。在这里,我们报告脆性 X 智力低下蛋白(FMRP)在脆性 X 综合征(FXS)患者中功能性缺失的 RNA 结合蛋白,也参与多种类型的癌症,在人类 iCCA 中过度表达,并且在 iCCA 转移组织中的表达显著增加。在转移性 iCCA 细胞系中沉默 FMRP 会影响细胞迁移和侵袭,提示 FMRP 在 iCCA 进展中起作用。此外,我们还证明 FMRP 定位于人类 iCCA 肿瘤巢的侵袭前沿以及迁移和侵袭的 iCCA 癌细胞的伪足和侵袭伪足突起中。在这里,FMRP 结合编码这些突起形成和/或功能的关键蛋白的几种 mRNA。特别是,我们发现 FMRP 结合并调节 Cortactin 的表达,Cortactin 是侵袭伪足形成的关键调节剂。总之,我们的研究结果表明,FMRP 可以通过调节细胞膜的可塑性和侵袭性 iCCA 细胞前缘的侵袭伪足形成来促进细胞侵袭性。