Activation of focal adhesion kinase in human lung cancer cells involves multiple and potentially parallel signaling events
Activation of focal adhesion kinase in human lung cancer cells involves multiple and potentially parallel signaling events
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DOI：
10.1111/j.1582-4934.2005.tb00364.x
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发表时间：
2005-04-01
影响因子：
5.3
通讯作者：
Jaklitsch, MT
中科院分区：
文献类型：
--
作者：
Mukhopadhyay, NK;Gordon, GJ;Jaklitsch, MT
整合素是跨质膜双向传输信号的粘附受体。在我们之前的报告中，我们已经证明鳞状肺癌细胞系 Calu-1 通过 β(1)-整联蛋白与 IV 型胶原 (Coll IV) 结合，并导致粘着斑激酶 (FAK) 磷酸化 (Ann Thorac Surg 2004；78:450-7)。考虑到 FAK 在细胞迁移、增殖和存活中的关键作用，我们在此研究了其在 Calu-1 细胞中激活和调节的潜在机制。我们观察到 FAK 的 Tyr(397)（FAK 的自磷酸化位点）和桩蛋白（FAK 的直接下游底物）在 Calu-1 细胞粘附到 Coll IV 后发生磷酸化。根据过氧钒酸盐处理测定，FAK 在 Coll IV 或未包被的平板上增殖期间保持磷酸化状态 72 小时。 Calu-1 细胞暴露于 60 μM 金雀异黄素，可降低 FAK 磷酸化（7.6 倍）和细胞增殖。 Coll IV 附着后，细胞外信号调节激酶 (ERK) 也被磷酸化。 1-5 mu M 细胞松弛素 D 破坏 Calu-1 细胞骨架完整性，导致细胞粘附抑制（50% 至 75%，p < 0.19 - 6.6 x 10(-7)）和 ERK 磷酸化（2 倍），但对 FAK 磷酸化没有任何影响。 100 和 250 nM 浓度的蛋白激酶 C 抑制剂 Calphostin C 不会阻断 Coll IV 诱导的 FAK 磷酸化，但会以剂量依赖性方式激活 ERK。 β(1)-整合素对于 Coll IV 诱导的 FAK 激活至关重要，但根据免疫检测测定，它与 FAK 没有物理相关性。总的来说，该报告定义了 Calu-1 细胞中存在多个且可能平行的 Coll IV/β(1)-整合素介导的信号传导事件，其中涉及 FAK、ERK 和 PKC。
Integrins are adhesion receptors that transmit signals bidirectionally across the plasma membrane. In our previous report we have shown that the squamous lung cancer cell line, Calu-1, binds to collagen type IV (Coll IV) through beta(1)-integrin and results in phosphorylation of focal adhesion kinase (FAK) (Ann Thorac Surg 2004; 78:450-7). Considering the critical role of FAK in cell migration, proliferation, and survival, here we investigated potential mechanisms of its activation and regulation in Calu-1 cells. We observed the phosphorylation of Tyr(397) of FAK (the autophosphorylation site of FAK) and paxillin, the immediate downstream substrate of FAK following the adhesion of Calu-1 cells to Coll IV. FAK remains phosphorylated during proliferation either on Coll IV or on uncoated plates for 72 h, as determined by peroxivanadate treatment. Exposure of Calu-1 cells with 60 mu M genistein, reduces FAK phosphorylation (7.6 fold) and cell proliferation. Extracellular signal regulated kinases (ERKs) were also phosphorylated after Coll IV attachment. Disruption of Calu-1 cell cytoskeleton integrity by 1-5 mu M Cytochalasin D resulted in the inhibition of cell adhesion (50% to 75%, p < 0.19 - 6.6 x 10(-7)) and ERKs phosphorylation (2 fold) without any effect on FAK phosphorylation. Protein Kinase C inhibitor, Calphostin C at 100 and 250 nM concentrations did not block Coll IV induced FAK phosphorylation, but activated the ERKs in a dose dependent manner. beta(1)-integrin is essential for Coll IV induced FAK activation, but it is not physically associated with FAK as determined by immunodetection assay. Collectively, this report defines the existence of multiple and potentially parallel Coll IV/beta(1)-integrin mediated signaling events in Calu-1 cells, which involve FAK, ERKs, and PKC.