Radiation-stimulated ERK1/2 and JNK1/2 signaling can promote cell cycle progression in human colon cancer cells
Radiation-stimulated ERK1/2 and JNK1/2 signaling can promote cell cycle progression in human colon cancer cells
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DOI：
10.4161/cc.4.3.1249
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发表时间：
2005-03-01
期刊：
影响因子：
4.3
通讯作者：
Dent, P
中科院分区：
文献类型：
--
作者：
Carón, RW;Yacoub, A;Dent, P
在同基因人类癌细胞系统中，突变的活性 K-RAS 和 H-RAS 蛋白在暴露于电离辐射后调节信号通路活性和细胞周期进展的能力在很大程度上尚不清楚。亲本 HCT116 结直肠癌细胞中 K-RAS D13 表达的缺失使基础 ERK1/2、AKT 和 JNK1/2 活性减弱了约 70%。未检测到 P38 活性。删除表达激活的 K-RAS 的等位基因几乎消除了辐射诱导的所有信号通路的激活。缺乏活化 RAS 分子的 HCT116 细胞（H-RAS V12 细胞）中 H-RAS V12 的表达将基础 ERK1/2 和 AKT 活性恢复到亲本细胞中观察到的水平，但没有恢复或改变基础 JNK1/2 和 p38 活性。在亲代细胞中，与 PI3K/AKT 通路相比，辐射 (1 Gy) 引起更强的 ERK1/2 通路激活。在 H-RAS V12 细胞中，与 ERK1/2 通路相比，辐射引起更强的 PI3K/AKT 通路激活。辐射 (1 Gy) 在 24 小时内促进亲代 HCT116 细胞进入 S 期，但在缺乏 K-RAS D13 表达的 HCT116 细胞或 H-RAS V12 细胞中没有促进作用。在亲代细胞中，辐射刺激的 S 期进入与 ERK1/2、JNK1/2 和 PI3K 依赖性细胞周期蛋白 D1 和细胞周期蛋白 A 的表达增加相关，在辐射后 6 - 24 小时，细胞周期蛋白 E 的表达增加，程度较小。在缺乏 K-RAS D13 表达的细胞或 H-RAS V12 细胞中，辐射不会增加细胞周期蛋白 A 和细胞周期蛋白 D1 的表达。辐射（1 Gy）在暴露后 2-6 小时适度增强亲本细胞中 p53、hMDM2 和 p21 的表达，而在缺乏 K-RAS D13 表达的细胞中这种现象被消除。将 H-RAS V12 引入缺乏突变活性 RAS 的细胞中，部分恢复了辐射诱导的 p21 和 p53 表达，并增强了 hMDM2 的诱导，超出了亲代细胞中观察到的水平。总的来说，我们的研究结果表明，需要通过辐射协调激活多个信号通路，特别是 ERK1/2 和 JNK1/2，以提高 G(1) 和 S 期细胞周期蛋白的表达，并促进表达野生型 p53 的人结肠癌细胞进入 S 期。在 HCT116 细胞中，H-RAS V12 在辐射暴露后促进 hMDM2 表达，这与 p53 表达减少和细胞存活增加相关。
The abilities of mutated active K-RAS and H-RAS proteins, in an isogenic human carcinoma cell system, to modulate the activity of signaling pathways and cell cycle progression following exposure to ionizing radiation is largely unknown. Loss of K-RAS D13 expression in parental HCT116 colorectal carcinoma cells blunted basal ERK1/2, AKT and JNK1/2 activity by similar to 70%. P38 activity was not detected. Deletion of the allele to express activated K-RAS nearly abolished radiation-induced activation of all signaling pathways. Expression of H-RAS V12 in HCT116 cells lacking an activated RAS molecule (H-RAS V12 cells) restored basal ERK1/2 and AKT activity to that observed in parental cells, but did not restore or alter basal JNK1/2 and p38 activity. In parental cells radiation ( 1 Gy) caused stronger ERK1/2 pathway activation compared to that of the PI3K/AKT pathway. In H-RAS V12 cells radiation caused stronger PI3K/AKT pathway activation compared to that of the ERK1/2 pathway. Radiation ( 1 Gy) promoted S phase entry in parental HCT116 cells within 24h, but not in either HCT116 cells lacking K-RAS D13 expression or in H-RAS V12 cells. In parental cells radiation-stimulated S phase entry correlated with ERK1/2-, JNK1/2- and PI3K-dependent increased expression of cyclin D1 and cyclin A, and to a lesser extent cyclin E, 6 - 24 h after exposure. Cyclin A and cyclin D1 expression were not increased by radiation in cells lacking K-RAS D13 expression or in H-RAS V12 cells. Radiation ( 1 Gy) modestly enhanced expression of p53, hMDM2 and p21 in parental cells 2-6h after exposure, which was abolished in cells lacking K-RAS D13 expression. Introduction of H-RAS V12 into cells lacking mutant active RAS partially restored radiation-induced expression of p21 and p53, and enhanced the induction of hMDM2 beyond that observed in parental cells. Collectively, our findings argue that the coordinated activation of multiple signaling pathways, in particular ERK1/2 and JNK1/2, by radiation is required to elevate the expression of G(1) and S phase cyclin proteins and to promote S phase entry in human colon carcinoma cells expressing wild type p53. In HCT116 cells H-RAS V12 promotes hMDM2 expression after radiation exposure which correlates with reduced p53 expression and increased cell survival.