Pirou Caroline, Montazer-Torbati Fatemeh, Jah Nadège, Delmas Elisabeth, Lasbleiz Christelle, Mignotte Bernard, Renaud Flore
Laboratoire de Génétique et Biologie Cellulaire, EA4589, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université Paris-Saclay, École Pratique des Hautes Etudes (EPHE), PSL Research University, 2 Avenue de la Source de la Bièvre, Montigny-Le-Bretonneux 78180, France.
Cell Death Dis. 2017 Aug 31;8(8):e3023. doi: 10.1038/cddis.2017.404.
Neuroblastoma, a sympathetic nervous system tumor, accounts for 15% of cancer deaths in children. In contrast to most human tumors, p53 is rarely mutated in human primary neuroblastoma, suggesting impaired p53 activation in neuroblastoma. Various studies have shown correlations between fgf1 expression levels and both prognosis severity and tumor chemoresistance. As we previously showed that fibroblast growth factor 1 (FGF1) inhibited p53-dependent apoptosis in neuron-like PC12 cells, we initiated the study of the interaction between the FGF1 and p53 pathways in neuroblastoma. We focused on the activity of either extracellular FGF1 by adding recombinant rFGF1 in media, or of intracellular FGF1 by overexpression in human SH-SY5Y and mouse N2a neuroblastoma cell lines. In both cell lines, the genotoxic drug etoposide induced a classical mitochondrial p53-dependent apoptosis. FGF1 was able to inhibit p53-dependent apoptosis upstream of mitochondrial events in SH-SY5Y cells by both extracellular and intracellular pathways. Both rFGF1 addition and etoposide treatment increased fgf1 expression in SH-SY5Y cells. Conversely, rFGF1 or overexpressed FGF1 had no effect on p53-dependent apoptosis and fgf1 expression in neuroblastoma N2a cells. Using different FGF1 mutants (that is, FGF1, FGF1 and FGF1), we further showed that the C-terminal domain and phosphorylation of FGF1 regulate its intracrine anti-apoptotic activity in neuroblastoma SH-SY5Y cells. This study provides the first evidence for a role of an intracrine growth factor pathway on p53-dependent apoptosis in neuroblastoma, and could lead to the identification of key regulators involved in neuroblastoma tumor progression and chemoresistance.
神经母细胞瘤是一种交感神经系统肿瘤，占儿童癌症死亡病例的15%。与大多数人类肿瘤不同，p53在人类原发性神经母细胞瘤中很少发生突变，这表明神经母细胞瘤中p53激活受损。各种研究表明，fgf1表达水平与预后严重程度和肿瘤化疗耐药性之间存在相关性。正如我们之前所表明的，成纤维细胞生长因子1（FGF1）抑制神经元样PC12细胞中p53依赖性凋亡，我们启动了对神经母细胞瘤中FGF1和p53信号通路之间相互作用的研究。我们通过在培养基中添加重组rFGF1来关注细胞外FGF1的活性，或者通过在人SH-SY5Y和小鼠N2a神经母细胞瘤细胞系中过表达来关注细胞内FGF1的活性。在这两种细胞系中，基因毒性药物依托泊苷诱导经典的线粒体p53依赖性凋亡。FGF1能够通过细胞外和细胞内途径在SH-SY5Y细胞中线粒体事件上游抑制p53依赖性凋亡。添加rFGF1和依托泊苷处理均增加了SH-SY5Y细胞中fgf1的表达。相反，rFGF1或过表达的FGF1对神经母细胞瘤N2a细胞中p53依赖性凋亡和fgf1表达没有影响。使用不同的FGF1突变体（即FGF1、FGF1和FGF1），我们进一步表明FGF1的C末端结构域和磷酸化调节其在神经母细胞瘤SH-SY5Y细胞中的内分泌抗凋亡活性。这项研究首次证明了内分泌生长因子信号通路在神经母细胞瘤p53依赖性凋亡中的作用，并可能导致鉴定参与神经母细胞瘤肿瘤进展和化疗耐药性的关键调节因子。
