Protein kinase Cζ mediated Raf-1/extracellular-regulated kinase activation by daunorubicin
Protein kinase Cζ mediated Raf-1/extracellular-regulated kinase activation by daunorubicin
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DOI：
10.1182/blood-2002-05-1585
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发表时间：
2003-02-15
期刊：
影响因子：
20.3
通讯作者：
Laurent, G
中科院分区：
文献类型：
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作者：
Mansat-De Mas, V;Hernandez, H;Laurent, G
鉴于丝裂原激活蛋白激酶 (MAPK) 通路在应激条件下具有保护功能的新兴概念，我们研究了蒽环类柔红霉素 (DNR) 对 MAPK 信号传导的影响及其对 DNR 诱导的细胞毒性的可能贡献。我们发现，在 U937 细胞中，DNR 在 10 至 30 分钟内增加了细胞外调节激酶 (ERK) 的磷酸化，并刺激了 Raf-1 和细胞外调节激酶 1 (ERK1) 的活性。 ERK1 刺激可被丝裂原诱导的细胞外激酶 (MEK) 抑制剂 PD98059 或 Raf-1 抑制剂 8-溴-cAMP（环磷酸腺苷）完全阻断。然而，抗氧化剂 N-乙酰半胱氨酸 (N-Ac) 仅部分抑制 Raf-1 和 ERK1 刺激。此外，抑制DNR诱导的磷脂酰胆碱（PC）水解和随后的二酰甘油（DAG）产生的黄原酸盐化合物D609，以及阻断磷脂酰肌醇3激酶（PI3K）刺激的渥曼青霉素，仅部分抑制Raf-1和ERK1刺激。我们还观察到 DNR 刺激蛋白激酶 C zeta (PKCzeta)（一种非典型 PKC 同工型），并且 D609 和渥曼青霉素均显着抑制 DNR 触发的 PKCzeta 激活。最后，我们发现 PKCzeta 激酶缺陷突变体的表达导致 DNR 诱导的 ERK 磷酸化消失。总而言之，这些结果表明，DNR 激活经典的 Raf-1/MEK/ERK 通路，并且 Raf-1 激活是通过复杂的信号通路介导的，该通路至少涉及 2 个贡献者：PC 衍生的 DAG 和向 PKCzeta 汇聚的 PI3K 产物。此外，我们发现 Raf-1 和 MEK 抑制剂以及 PKCzeta 抑制使细胞对 DNR 诱导的细胞毒性敏感。
In light of the emerging concept of a protective function of the mitogen-activated protein kinase (MAPK) pathway under stress conditions, we investigated the influence of the anthracycline daunorubicin (DNR) on MAPK signaling and its possible contribution to DNR-induced cytotoxicity. We show that DNR increased phosphorylation of extracellular-regulated kinases (ERKs) and stimulated activities of both Raf-1 and extracellular-regulated kinase 1 (ERK1) within 10 to 30 minutes in U937 cells. ERK1 stimulation was completely blocked by either the mitogen-induced extracellular kinase (MEK) inhibitor PD98059 or the Raf-1 inhibitor 8-bromo-cAMP (cyclic adenosine monophosphate). However, only partial inhibition of Raf-1 and ERK1 stimulation was observed with the antioxidant N-acetylcysteine (N-Ac). Moreover, the xanthogenate compound D609 that inhibits DNR-induced phosphatidylcholine (PC) hydrolysis and subsequent diacylglycerol (DAG) production, as well as wortmannin that blocks phospholnositide-3 kinase (PI3K) stimulation, only partially inhibited Raf-1 and ERK1 stimulation. We also observed that DNR stimulated protein kinase C zeta (PKCzeta), an atypical PKC isoform, and that both D609 and wortmannin significantly inhibited DNR-triggered PKCzeta activation. Finally, we found that the expression of PKCzeta kinase-defective mutant resulted in the abrogation of DNR-induced ERK phosphorylation. Altogether, these results demonstrate that DNR activates the classical Raf-1/MEK/ERK pathway and that Raf-1 activation is mediated through complex signaling pathways that involve at least 2 contributors: PC-derived DAG and PI3K products that converge toward PKCzeta. Moreover, we show that both Raf-1 and MEK inhibitors, as well as PKCzeta inhibition, sensitized cells to DNR-induced cytotoxicity.