Nabeshima K, Asada Y, Inoue T, Kataoka H, Shimao Y, Sumiyoshi A, Koono M
Second Department of Pathology, Miyazaki Medical College, Japan.
Lab Invest. 1997 Jan;76(1):139-51.
We previously presented a two-dimensional cell motility assay using L-10, a highly metastatic variant of the human rectal adenocarcinoma cell line RCM-1, as a motility model of tumor cells of epithelial origin. In this model, L-10 cells moved outward from the cell islands mainly as a localized coherent sheet of cells when stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA). Electronmicroscopic study of the migrating cell sheets revealed that wide intercellular gaps had developed at the lower portion of the cells, allowing them to extend leading lamellae, whereas close cell-cell contacts remained at the upper portion of the cells. In the present study, the mechanism involved in this localized modulation of cell-cell adhesion at the lower portion of the cells was investigated with special reference to E-cadherin expression. E-cadherin immunostaining, which was demonstrated using an anti-E-cadherin mAb, HECD-1, was decreased in migrating L-10 cell sheets. Apparently, however, E-cadherin was involved in the sheet formation of migrating cells because simultaneous or sequential treatment with TPA and HECD-1 inhibited sheet formation and caused scattering of migrating cells. With immunoelectron microscopic study, E-cadherin immunoreactivity was confined to the upper portion of migrating cells and lost at the lower portion. The level of E-cadherin and alpha-catenin expression was not altered by TPA treatment, although tyrosine phosphorylation of E-cadherin and catenins increased 1.6- to 1.9-fold. We propose that cells are released from cell-cell adhesion only at the lower portion of the cells via phosphorylation of the E-cadherin-catenin complex when stimulated with TPA. This change allows the cells to extend leading lamella and thus move together as coherent sheets (cohort migration).
我们之前提出了一种二维细胞运动分析方法，使用人直肠腺癌细胞系RCM-1的高转移变体L-10作为上皮来源肿瘤细胞的运动模型。在该模型中，当用12-O-十四烷酰佛波醇-13-乙酸酯（TPA）刺激时，L-10细胞主要作为局部连贯的细胞片从细胞岛向外移动。对迁移细胞片的电子显微镜研究表明，细胞下部出现了宽阔的细胞间隙，使其能够伸出前缘片层，而细胞上部仍保持紧密的细胞间接触。在本研究中，特别参考E-钙黏蛋白的表达，对细胞下部这种局部细胞间黏附调节所涉及的机制进行了研究。使用抗E-钙黏蛋白单克隆抗体HECD-1进行的E-钙黏蛋白免疫染色在迁移的L-10细胞片中减少。然而，显然E-钙黏蛋白参与了迁移细胞的片层形成，因为用TPA和HECD-1同时或顺序处理会抑制片层形成并导致迁移细胞散射。通过免疫电子显微镜研究，E-钙黏蛋白免疫反应性局限于迁移细胞的上部，而在下部消失。尽管E-钙黏蛋白和连环蛋白的酪氨酸磷酸化增加了1.6至1.9倍，但TPA处理并未改变E-钙黏蛋白和α-连环蛋白的表达水平。我们提出，当受到TPA刺激时，细胞仅在细胞下部通过E-钙黏蛋白-连环蛋白复合物的磷酸化而从细胞间黏附中释放出来。这种变化使细胞能够伸出前缘片层，从而作为连贯的片层一起移动（群体迁移）。
