Nejjari M, Hafdi Z, Dumortier J, Bringuier A F, Feldmann G, Scoazec J Y
Laboratoire de Biologie Cellulaire, Unité INSERM U327, Faculté de Médecine Xavier Bichat, Paris, France.
Int J Cancer. 1999 Nov 12;83(4):518-25. doi: 10.1002/(sici)1097-0215(19991112)83:4<518::aid-ijc14>3.0.co;2-q.
Liver carcinogenesis is associated with striking changes in the integrin repertoire of hepatocytes, including the overexpression of the laminin and collagen receptors alpha1beta1 and the de novo induction of the laminin receptor alpha6beta1. Our aim was to analyze the role of pro-inflammatory cytokines, interferons and fibrogenic cytokines TGF-beta and FGF2 in the regulation of the expression of beta1 integrins by neoplastic hepatocytes. The 2 human hepatocellular cell lines HepG2 and Hep3B were used as models. Integrin expression was assessed by qualitative methods (immunocytochemistry, Western blotting) and semi-quantitative techniques (FACS, cellular ELISA), before and after stimulation by TNFalpha, IL1-beta, TGF-beta, FGF2, interferon gamma and interferon alpha-2b. HepG2 and Hep3B constitutively expressed alpha1, alpha2, alpha6 and beta1 chains. A 24 to 48-hr stimulation with pro-inflammatory cytokines, TGF-beta and FGF2 induced a significant increase in the concentrations of all integrin chains. The maximum induction was registered for beta1 chain, which presented increases amounting up to 3, 4 and 7 times the control values in the presence of, respectively, TNF alpha/IL1-beta, TGF-beta and FGF2. Interferons had no direct effect on integrin expression and partially antagonized the effects of TNF alpha and TGF-beta. The increased concentrations of integrin chains were associated with an increased membrane expression of the corresponding dimers and with an increased adhesion of stimulated hepatocytes to laminin, which was antagonized by neutralizing anti-beta1 and anti-alpha6 antibodies. Finally, anti-alpha6 antibody inhibited the migration of HepG2 and Hep3B cells in reconstituted basement membrane. Our results suggest that the stimulation of alpha6beta1 integrin expression in hepatocarcinoma cells is essential for cell adhesion and migration.
肝癌发生与肝细胞整合素库的显著变化相关，包括层粘连蛋白和胶原蛋白受体α1β1的过表达以及层粘连蛋白受体α6β1的从头诱导。我们的目的是分析促炎细胞因子、干扰素和促纤维化细胞因子转化生长因子-β（TGF-β）及成纤维细胞生长因子2（FGF2）在肿瘤性肝细胞对β1整合素表达调控中的作用。使用两种人肝癌细胞系HepG2和Hep3B作为模型。在经肿瘤坏死因子α（TNFα）、白细胞介素1-β（IL1-β）、TGF-β、FGF2、干扰素γ和干扰素α - 2b刺激之前和之后，通过定性方法（免疫细胞化学、蛋白质印迹法）和半定量技术（荧光激活细胞分选术、细胞酶联免疫吸附测定）评估整合素表达。HepG2和Hep3B组成性表达α1、α2、α6和β1链。用促炎细胞因子、TGF-β和FGF2进行24至48小时的刺激可导致所有整合素链的浓度显著增加。β1链的诱导最为明显，在分别存在TNFα/IL1-β、TGF-β和FGF2的情况下，其增加量分别高达对照值的3倍、4倍和7倍。干扰素对整合素表达无直接影响，并部分拮抗TNFα和TGF-β的作用。整合素链浓度的增加与相应二聚体的膜表达增加以及受刺激肝细胞与层粘连蛋白的黏附增加相关，而这种黏附可被中和性抗β1和抗α6抗体拮抗。最后，抗α6抗体抑制了HepG2和Hep3B细胞在重组基底膜中的迁移。我们的结果表明，肝癌细胞中α6β1整合素表达的刺激对于细胞黏附和迁移至关重要。
