Zhou Y, Dziak E, Opas M
Department of Anatomy and Cell Biology, University of Toronto, Ontario, Canada.
J Cell Physiol. 1993 Apr;155(1):14-26. doi: 10.1002/jcp.1041550104.
In the present study, we have examined the regulation of attachment, onset of proliferation and the subsequent growth, in vitro, of chick retinal pigmented epithelial (RPE) cells as a function of the nature of the substratum and of either the activation or inhibition of protein kinase C (PKC). The RPE cells have an adhesive preference for protein carpets which contain laminin. This preference disappears gradually with time in culture. The adhesion of RPE cells to fibronectin is shown to be a receptor-mediated process which involves the RGD recognition signal. This study also demonstrates that a PKC activator, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), affects RPE cell adhesion in a substratum-dependent manner. Exposure of RPE cells to TPA lowers the cell attachment efficacy to ECM protein substrata but does not affect cell attachment to plastic. The onset of cell proliferation is accelerated by TPA on all of the substrata tested. The minimal duration of an effective TPA pulse exerting a long-lasting influence on RPE cell proliferation is between 1.5 and 3.5 hr. Stimulation of cell proliferation by TPA in long-term cultures is independent of the nature of the growth substratum. The acceleration of the onset of cell proliferation by TPA is sensitive to 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7), an inhibitor of conventional PKC, and thus appears to be dependent on the activation of conventional PKC. H7 also affects cell-cell contacts, causing an alteration in the shape ("squaring") of RPE cells packed into large colonies. Conversely, the effects of TPA on both the attachment and the long-term proliferation of RPE cells are not dependent a conventional PKC isotype, since H7 cannot abolish the influence of TPA on either process. We conclude that the effect of TPA on long-term proliferation of RPE cells is either dependent on a novel PKC isotype or independent of PKC.
在本研究中，我们检测了鸡视网膜色素上皮（RPE）细胞在体外的附着调节、增殖起始及后续生长情况，这些均是作为基质性质以及蛋白激酶C（PKC）激活或抑制作用的函数。RPE细胞对含有层粘连蛋白的蛋白毯具有黏附偏好。随着培养时间的延长，这种偏好会逐渐消失。研究表明，RPE细胞与纤连蛋白的黏附是一个受体介导的过程，涉及RGD识别信号。本研究还证明，PKC激活剂12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯（TPA）以基质依赖的方式影响RPE细胞黏附。将RPE细胞暴露于TPA会降低其对细胞外基质（ECM）蛋白基质的细胞附着效率，但不影响细胞对塑料的附着。在所有测试的基质上，TPA均可加速细胞增殖的起始。对RPE细胞增殖产生持久影响的有效TPA脉冲的最短持续时间在1.5至3.5小时之间。在长期培养中，TPA对细胞增殖的刺激与生长基质的性质无关。TPA对细胞增殖起始的加速作用对传统PKC抑制剂1 -（5 - 异喹啉磺酰基）- 2 - 甲基哌嗪（H7）敏感，因此似乎依赖于传统PKC的激活。H7还会影响细胞间接触，导致聚集形成大菌落的RPE细胞形状发生改变（“变方”）。相反，TPA对RPE细胞附着和长期增殖的影响不依赖于传统的PKC同工型，因为H7无法消除TPA对这两个过程的影响。我们得出结论，TPA对RPE细胞长期增殖的影响要么依赖于一种新型PKC同工型，要么与PKC无关。
