Celecoxib induces apoptosis by inhibiting 3-phosphoinositide-dependent protein kinase-1 activity in the human colon cancer HT-29 cell line
Celecoxib induces apoptosis by inhibiting 3-phosphoinositide-dependent protein kinase-1 activity in the human colon cancer HT-29 cell line
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DOI：
10.1074/jbc.m201119200
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发表时间：
2002-08-02
影响因子：
4.8
通讯作者：
Ogier-Denis, E
中科院分区：
文献类型：
--
作者：
Arico, S;Pattingre, S;Ogier-Denis, E
抑制环氧合酶（考克斯）活性的非甾体抗炎药是通过COX依赖性和/或COX非依赖性途径对癌细胞发挥其抗增殖和促凋亡作用的强效抗炎药。塞来昔布是一种考克斯-2特异性抑制剂，已被证明可减少家族性腺瘤性息肉病患者的腺瘤性结直肠息肉数量。在这里，我们表明塞来昔布通过抑制3-磷酸肌醇依赖性激酶1（PDK 1）活性来诱导结肠癌细胞系HT-29的细胞凋亡。该效应与抑制PDK 1下游底物Akt/蛋白激酶B（PK B）在两个调节位点Thr（308）和Ser（473）上的磷酸化相关。然而，Akt/PKB（肉豆蔻酰化PKB）组成型活性形式的表达对塞来昔布诱导的细胞死亡具有较低的保护作用。相反，PDK 1组成型活性突变体（PDK 1（A280 V））的过表达与泛半胱天冬酶抑制剂苄氧羰基-Val-Ala-Asp-氟甲基酮一样有效，可损害塞来昔布诱导的细胞凋亡。相比之下，表达PDK 1激酶缺陷突变体（PDK 1（K114 G））的细胞对塞来昔布保持敏感。此外，体外测量显示塞来昔布是PDK 1活性的潜在抑制剂，IC 50 = 3.5 μ M。这些数据表明，PDK 1信号的抑制参与塞来昔布在HT-29细胞中的促凋亡作用。
Nonsteroidal anti-inflammatory drugs, which inhibit cyclooxygenase (COX) activity, are powerful antineoplastic agents that exert their antiproliferative and proapoptotic effects on cancer cells by COX-dependent and/or COX-independent pathways. Celecoxib, a COX-2-specific inhibitor, has been shown to reduce the number of adenomatous colorectal polyps in patients with familial adenomatous polyposis. Here, we show that celecoxib induces apoptosis in the colon cancer cell line HT-29 by inhibiting the 3-phosphoinositide-dependent kinase 1 (PDK1) activity. This effect was correlated with inhibition of the phosphorylation of the PDK1 downstream substrate Akt/protein kinase B (PKB) on two regulatory sites, Thr(308) and Ser(473). However, expression of a constitutive active form of Akt/PKB (myristoylated PKB) has a low protective effect toward celecoxib-induced cell death. In contrast, overexpression of constitutive active mutant of PDK1 (PDK1(A280V)) was as potent as the pan-caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, to impair celecoxib-induced apoptosis. By contrast, cells expressing a kinase-defective mutant of PDK1 (PDK1(K114G)) remained sensitive to celecoxib. Furthermore, in vitro measurement reveals that celecoxib was a potential inhibitor of PDK1 activity with an IC50 = 3.5 muM. These data indicate that inhibition of PDK1 signaling is involved in the proapoptotic effect of celecoxib in HT-29 cells.