Li Mei-Hong, Sanchez Teresa, Pappalardo Anna, Lynch Kevin R, Hla Timothy, Ferrer Fernando
Center for Vascular Biology, University of Connecticut Health Center, Farmington, Connecticut, USA.
Mol Cancer Res. 2008 Oct;6(10):1649-56. doi: 10.1158/1541-7786.MCR-07-2048.
Connective tissue growth factor (CTGF), a member of the CCN family of secreted matricellular proteins, regulates fibrosis, angiogenesis, cell proliferation, apoptosis, tumor growth, and metastasis. However, the role of CTGF and its regulation mechanism in Wilms' tumor remains largely unknown. We found that the bioactive lipid sphingosine-1-phosphate (S1P) induced CTGF expression in a concentration- and time-dependent manner in a Wilms' tumor cell line (WiT49), whereas FTY720-phosphate, an S1P analogue that binds all S1P receptors except S1P2, did not. Further, the specific S1P2 antagonist JTE-013 completely inhibited S1P-induced CTGF expression, whereas the S1P1 antagonist VPC44116 did not, indicating that this effect was mediated by S1P2. This was confirmed by adenoviral transduction of S1P2 in WiT49 cells, which showed that overexpression of S1P2 increased the expression of CTGF. Induction of CTGF by S1P was sensitive to ROCK inhibitor Y-27632 and c-Jun NH2-terminal kinase inhibitor SP600125, suggesting the requirement of RhoA/ROCK and c-Jun NH2-terminal kinase pathways for S1P-induced CTGF expression. Interestingly, the expression levels of CTGF were decreased in 8 of 10 Wilms' tumor tissues compared with matched normal tissues by quantitative real-time PCR and Western blot analysis. In vitro, human recombinant CTGF significantly inhibited the proliferation of WiT49 cells. In addition, overexpression of CTGF resulted in significant inhibition of WiT49 cell growth. Taken together, these data suggest that CTGF protein induced by S1P2 might act as a growth inhibitor in Wilms' tumor.
结缔组织生长因子（CTGF）是分泌性基质细胞蛋白CCN家族的成员之一，可调节纤维化、血管生成、细胞增殖、凋亡、肿瘤生长和转移。然而，CTGF在肾母细胞瘤中的作用及其调控机制仍不清楚。我们发现生物活性脂质鞘氨醇-1-磷酸（S1P）在肾母细胞瘤细胞系（WiT49）中以浓度和时间依赖性方式诱导CTGF表达，而FTY720-磷酸（一种与除S1P2之外的所有S1P受体结合的S1P类似物）则不能。此外，特异性S1P2拮抗剂JTE-013完全抑制S1P诱导的CTGF表达，而S1P1拮抗剂VPC44116则不能，这表明该效应是由S1P2介导的。通过在WiT49细胞中腺病毒转导S1P2证实了这一点，结果显示S1P2的过表达增加了CTGF的表达。S1P对CTGF的诱导对ROCK抑制剂Y-27632和c-Jun氨基末端激酶抑制剂SP600125敏感，提示RhoA/ROCK和c-Jun氨基末端激酶途径参与S1P诱导的CTGF表达。有趣的是，通过定量实时PCR和蛋白质印迹分析发现，与配对的正常组织相比，10例肾母细胞瘤组织中有8例CTGF表达水平降低。在体外，人重组CTGF显著抑制WiT49细胞的增殖。此外，CTGF的过表达导致WiT49细胞生长受到显著抑制。综上所述，这些数据表明S1P2诱导的CTGF蛋白可能在肾母细胞瘤中作为生长抑制剂发挥作用。
