Involvement of MAP-kinase, PI3-kinase and EGF-receptor in the stimulatory effect of Neurotensin on DNA synthesis in PC3 cells
Involvement of MAP-kinase, PI3-kinase and EGF-receptor in the stimulatory effect of Neurotensin on DNA synthesis in PC3 cells
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DOI：
10.1016/j.regpep.2004.03.004
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发表时间：
2004-08-15
影响因子：
--
通讯作者：
Carraway, RE
中科院分区：
文献类型：
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作者：
Hassan, S;Dobner, PR;Carraway, RE
神经降压素（NT）促进前列腺癌上皮细胞生长的机制尚未明确。在这里，雄激素非依赖性PC 3细胞，表达高水平的1型NT受体（NTR 1），用于检查参与表皮生长因子受体（EGFR），促分裂原活化蛋白激酶（ERK，SAPK/JNK和p38），PI 3激酶和PKC在NT的促有丝分裂作用。NT剂量依赖性地（0.1-30 nM）增强EGFR、ERK和Akt的磷酸化，如通过Western印迹测量的，在3分钟内达到最大水平。这些效应与培养基中EGF样物质的蓄积（通过EGFR结合测定）和DNA合成增加2倍（通过[H-3]胸苷掺入测定）相关。NT对DNA合成的促进作用与EGF无相加作用。NT诱导的EGFR/ERK/Akt磷酸化和DNA合成的刺激被EGFR-酪氨酸激酶抑制剂（AG 1478，PD 153035），金属内肽酶抑制剂phosphoramidon和肝素抑制，但不被中和抗EGF抗体抑制。因此，通过NT的EGFR反式激活涉及肝素结合EGF（HB-EGF或双调蛋白）而不是EGF。PLC抑制剂（U 73122）、PKC抑制剂（bisindolylmaleimide、staurosporine、rottlerin）、MEK抑制剂（U 0126）和PI 3激酶抑制剂（wortmannin、LY 294002）可减弱NT对EGFR/ERK/Akt活化和DNA合成的影响。我们的结论是，NT通过PKC依赖性配体介导的EGFR反式激活刺激PC 3细胞中的有丝分裂，从而以PI 3激酶依赖的方式刺激Raf-MEK-ERK通路。(C)2004 Elsevier B. V.保留所有权利。
The mechanism by which neurotensin (NT) promotes the growth of prostate cancer epithelial cells is not yet defined. Here, androgen-independent PC3 cells, which express high levels of the type 1 NT-receptor (NTR1), are used to examine the involvement of epidermal growth factor receptor (EGFR), mitogen-activated protein kinases (ERK, SAPK/JNK and p38), PI3 kinase and PKC in the mitogenic effect of NT. NT dose dependently (0.1-30 nM) enhanced phosphorylation of EGFR, ERK and Akt, reaching maximal levels within 3 min as measured by Western blotting. These effects were associated with an accumulation of EGF-like substance(s) in the medium (assayed by EGFR binding) and a 2-fold increase in DNA synthesis (assayed by [H-3]thymidine incorporation). The DNA synthesis enhancement by NT was non-additive with that of EGF. The NT-induced stimulation of EGFR/ERK/Akt phosphorylation and DNA synthesis was inhibited by EGFR-tyrosine kinase inhibitors (AG1478, PD153035), metallo-endopeptidase inhibitor phosphoramidon and by heparin, but not by neutralizing anti-EGF antibody. Thus, transactivation of EGFR by NT involved heparin-binding EGF (HB-EGF or amphiregulin) rather than EGF. The effects of NT on EGFR/ERK/Akt activation and DNA synthesis were attenuated by PLC-inhibitor (U73122), PKC-inhibitors (bisindolylmaleimide, staurosporine, rottlerin), MEK inhibitor (U0126) and PI3 kinase inhibitors (wortmannin, LY 294002). We conclude that NT stimulated mitogenesis in PC3 cells by a PKC-dependent ligand-mediated transactivation of EGFR, which led to stimulation of the Raf-MEK-ERK pathway in a PI3 kinase-dependent manner. (C) 2004 Elsevier B.V. All rights reserved.