Cai J, Jiang W G, Mansel R E
Metastasis Research Group, University Department of Surgery, University of Wales College of Medicine, Cardiff CF4 4XN, UK.
Int J Mol Med. 1998 Jan;1(1):273-8.
Abnormal gap junction communication (GJC) has been associated with carcinogenesis. We investigated the role of endothelial cell GJC and connexin 43 (Cx43), the main gap junction protein in these cells, during tumour cell extravasation. GJC was determined by the ability of cells to transfer Lucifer yellow, to neighbouring cells. Tumour-endothelial interaction was assessed by DiI assay. Connexin 43 expression and tyrosine phosphorylation were measured by immunoprecipitation and Western blotting. Co-culturing of ECV304 endothelial cells with human breast cancer cells resulted in a rapid and transient loss of communication competence of ECV304. This inhibition was maximal within 5 min. GJC was almost fully restored in 2 h. The co-culturing also resulted in an increase in the tyrosine phosphorylation of CX43. The pattern of phosphorylation was similar to the loss and the recovery of GJC in ECV304. We conclude that interaction of tumour cells with endothelium effectively inhibits GJC of endothelial cells, which is attributed to the increased tyrosine phosphorylation of connexin 43. This may contribute to the extravasation of tumour cells from the circulation, an essential step in the establishment of metastasis.
异常的间隙连接通讯（GJC）与肿瘤发生有关。我们研究了内皮细胞GJC和连接蛋白43（Cx43，这些细胞中的主要间隙连接蛋白）在肿瘤细胞外渗过程中的作用。通过细胞将荧光素黄转移至相邻细胞的能力来测定GJC。通过DiI测定法评估肿瘤-内皮相互作用。通过免疫沉淀和蛋白质印迹法测量连接蛋白43的表达和酪氨酸磷酸化。将ECV304内皮细胞与人乳腺癌细胞共培养导致ECV304的通讯能力迅速且短暂丧失。这种抑制在5分钟内达到最大。GJC在2小时内几乎完全恢复。共培养还导致CX43的酪氨酸磷酸化增加。磷酸化模式与ECV304中GJC的丧失和恢复相似。我们得出结论，肿瘤细胞与内皮的相互作用有效抑制内皮细胞的GGJC，这归因于连接蛋白43酪氨酸磷酸化增加。这可能有助于肿瘤细胞从循环中渗出，这是转移形成的关键步骤。
