Protease-activated receptor 2 in colon cancer - Trypsin-induced MAPK phosphorylation and cell proliferation are mediated by epidermal growth factor receptor transactivation
Protease-activated receptor 2 in colon cancer - Trypsin-induced MAPK phosphorylation and cell proliferation are mediated by epidermal growth factor receptor transactivation
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DOI：
10.1074/jbc.m401430200
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发表时间：
2004-05-14
影响因子：
4.8
通讯作者：
Laburthe, M
中科院分区：
文献类型：
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作者：
Darmoul, D;Gratio, V;Laburthe, M
多项证据表明，肿瘤来源的胰蛋白酶有助于癌细胞的生长和侵袭。我们最近发现，胰蛋白酶通过激活 G 蛋白偶联受体蛋白酶激活受体 2 (PAR2)，成为结肠癌细胞的有效生长因子。在这里，我们分析了 PAR2 激活下游导致 HT-29 细胞中结肠癌细胞增殖的信号通路。我们的数据与丝氨酸蛋白酶胰蛋白酶或特定的 PAR2 激活肽 (AP2) 激活 PAR2 后发生的以下级联事件一致：(i) 基质金属蛋白酶依赖性转化生长因子 (TGF)-α 的释放，如 TGF-α 阻断抗体和培养基中 TGF-α 的测量所证明的； (ii) TGF-α介导的表皮生长因子受体（EGF-R)的激活和随后的EGF-R磷酸化； (iii) ERK1/2 的激活和随后的细胞增殖。这些事件之间的联系通过以下事实得到证明：PAR2 激活后对细胞增殖和 ERK1/2 的刺激可被金属蛋白酶抑制剂巴马司他、TGF-α 中和抗体、EGF-R 配体结合域阻断抗体以及 EGF-R 酪氨酸激酶抑制剂 AG1478 和 PD168393 逆转。因此，EGF-R 的反式激活似乎是 PAR2 激活导致结肠癌细胞生长的主要机制。通过使用 Src 酪氨酸激酶抑制剂 PP2，我们进一步表明 Src 在 PAR2 介导的 ERK1/2 激活和细胞增殖中发挥许可作用，可能作用于 EGF-R 的下游。这些数据解释了胰蛋白酶如何对结肠癌细胞发挥强大的营养作用，并强调了 EGF-R 反式激活的关键作用。
Several lines of evidence suggest that tumor-derived trypsin contributes to the growth and invasion of cancer cells. We have recently shown that trypsin is a potent growth factor for colon cancer cells through activation of the G protein-coupled receptor protease-activated receptor 2 (PAR2). Here, we analyzed the signaling pathways downstream of PAR2 activation that lead to colon cancer cell proliferation in HT-29 cells. Our data are consistent with the following cascade of events upon activation of PAR2 by the serine protease trypsin or the specific PAR2-activating peptide (AP2): (i) a matrix metalloproteinase-dependent release of transforming growth factor (TGF)-alpha, as demonstrated with TGF-alpha-blocking antibodies and measurement of TGF-alpha in culture medium; (ii) TGF-alpha-mediated activation of epidermal growth factor receptor (EGF-R) and subsequent EGF-R phosphorylation; and (iii) activation of ERK1/2 and subsequent cell proliferation. The links between these events are demonstrated by the fact that stimulation of cell proliferation and ERK1/2 upon activation of PAR2 is reversed by the metalloproteinase inhibitor batimastat, TGF-alpha-neutralizing antibodies, EGF-R ligand binding domain-blocking antibodies, and the EGF-R tyrosine kinase inhibitors AG1478 and PD168393. Therefore, transactivation of EGF-R appears to be a major mechanism whereby activation of PAR2 results in colon cancer cell growth. By using the Src tyrosine kinase inhibitor PP2, we further showed that Src plays a permissive role for PAR2-mediated ERK1/2 activation and cell proliferation, probably acting downstream of the EGF-R. These data explain how trypsin exerts robust trophic action on colon cancer cells and underline the critical role of EGF-R transactivation.