Takai Erina, Tsukimoto Mitsutoshi, Harada Hitoshi, Kojima Shuji
Department of Radiation Biosciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba, 278-8510, Japan.
Purinergic Signal. 2014 Sep;10(3):487-97. doi: 10.1007/s11302-014-9411-x. Epub 2014 Mar 14.
Extracellular nucleotides, such as ATP, are released from cells and play roles in various physiological and pathological processes through activation of P2 receptors. Here, we show that autocrine signaling through release of ATP and activation of P2X7 receptor influences migration of human lung cancer cells. Release of ATP was induced by stimulation with TGF-β1, which is a potent inducer of cell migration, in human lung cancer H292 cells, but not in noncancerous BEAS-2B cells. Treatment of H292 cells with a specific antagonist of P2X7 receptor resulted in suppression of TGF-β1-induced migration. PC-9 human lung cancer cells released a large amount of ATP under standard cell culture conditions, and P2X7 receptor-dependent dye uptake was observed even in the absence of exogenous ligand, suggesting constitutive activation of P2X7 receptor in this cell line. PC-9 cells showed high motile activity, which was inhibited by treatment with ecto-nucleotidase and P2X7 receptor antagonists, whereas a P2X7 receptor agonist enhanced migration. PC-9 cells also harbor a constitutively active mutation in epidermal growth factor receptor (EGFR). Treatment with EGFR tyrosine kinase inhibitor AG1478 suppressed both cell migration and P2X7 receptor expression in PC-9 cells. Compared to control PC-9 cells, cells treated with P2X7 antagonist exhibited broadened lamellipodia around the cell periphery, while AG1478-treated cells lacked lamellipodia. These results indicate that P2X7-mediated signaling and EGFR signaling may regulate migration of PC-9 cells through distinct mechanisms. We propose that autocrine ATP-P2X7 signaling is involved in migration of human lung cancer cells through regulation of actin cytoskeleton rearrangement.
细胞外核苷酸，如三磷酸腺苷（ATP），从细胞中释放出来，并通过激活P2受体在各种生理和病理过程中发挥作用。在此，我们表明，通过ATP释放和P2X7受体激活的自分泌信号影响人肺癌细胞的迁移。在人肺癌H292细胞中，三磷酸甘油酸（TGF-β1）刺激可诱导ATP释放，TGF-β1是一种强大的细胞迁移诱导剂，但在非癌性BEAS-2B细胞中则不会。用P2X7受体的特异性拮抗剂处理H292细胞可导致TGF-β1诱导的迁移受到抑制。PC-9人肺癌细胞在标准细胞培养条件下释放大量ATP，即使在没有外源性配体的情况下也观察到P2X7受体依赖性染料摄取，这表明该细胞系中P2X7受体的组成性激活。PC-9细胞表现出高运动活性，用胞外核苷酸酶和P2X7受体拮抗剂处理可抑制这种活性，而P2X7受体激动剂则增强迁移。PC-9细胞在表皮生长因子受体（EGFR）中也存在组成性激活突变。用EGFR酪氨酸激酶抑制剂AG1478处理可抑制PC-9细胞的细胞迁移和P2X7受体表达。与对照PC-9细胞相比，用P2X7拮抗剂处理的细胞在细胞周边显示出加宽的片状伪足，而用AG1478处理的细胞则没有片状伪足。这些结果表明，P2X7介导的信号传导和EGFR信号传导可能通过不同机制调节PC-9细胞的迁移。我们提出，自分泌ATP-P2X7信号传导通过调节肌动蛋白细胞骨架重排参与人肺癌细胞的迁移。
