Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States of America.
PLoS One. 2013 Apr 30;8(4):e63150. doi: 10.1371/journal.pone.0063150. Print 2013.
In human prostate cancer cells, a selective Epac agonist, 8-CPT-2Me-cAMP, upregulates cell proliferation and survival via activation of Ras-MAPK and PI- 3-kinase-Akt-mTOR signaling cascades. Here we examine the role of inflammatory mediators in Epac1-induced cellular proliferation by determining the expression of the pro-inflammatory markers p-cPLA2, COX-2, and PGE2 in prostate cancer cells treated with 8-CPT-2Me-cAMP.
We employed inhibitors of COX-2, mTORC1, and mTORC2 to probe cyclic AMP-dependent pathways in human prostate cancer cells. RNAi targeting Epac1, Raptor, and Rictor was also employed in these studies.
8-CPT-2Me-cAMP treatment caused a 2-2.5-fold increase of p-cPLA2(S505), COX-2, and PGE2 levels in human prostate cancer cell lines. Pretreatment of cells with the COX-2 inhibitor SC-58125 or the EP4 antagonist AH-23848, or with an inhibitor of mTORC1 and mTORC2, Torin1, significantly reduced the Epac1-dependent increase of p-cPLA2 and COX-2, p-S6-kinase(T389), and p-AKT(S473). In addition, Epac1-induced protein and DNA synthesis were greatly reduced upon pretreatment of cells with either COX-2, EP4, or mTOR inhibitors. Transfection of prostate cancer cells with Epac1 dsRNA, Raptor dsRNA, or Rictor dsRNA profoundly reduced Epac1-dependent increases in p-cPLA2 and COX-2.
We show that Epac1, a downstream effector of cAMP, functions as a pro-inflammatory modulator in prostate cancer cells and promotes cell proliferation and survival by upregulating Ras-MAPK, and PI 3-kinase-Akt-mTOR signaling.
在人类前列腺癌细胞中，选择性 Epac 激动剂 8-CPT-2Me-cAMP 通过激活 Ras-MAPK 和 PI-3-kinase-Akt-mTOR 信号级联而上调细胞增殖和存活。在此，我们通过检测用 8-CPT-2Me-cAMP 处理的前列腺癌细胞中促炎标志物 p-cPLA2、COX-2 和 PGE2 的表达，来研究炎症介质在 Epac1 诱导的细胞增殖中的作用。
我们采用 COX-2、mTORC1 和 mTORC2 的抑制剂来研究人前列腺癌细胞中 cAMP 依赖性通路。在这些研究中，还采用了靶向 Epac1、Raptor 和 Rictor 的 RNAi。
8-CPT-2Me-cAMP 处理导致人前列腺癌细胞系中 p-cPLA2(S505)、COX-2 和 PGE2 水平增加 2-2.5 倍。用 COX-2 抑制剂 SC-58125 或 EP4 拮抗剂 AH-23848 预处理细胞，或用 mTORC1 和 mTORC2 的抑制剂 Torin1 预处理细胞，均可显著降低 Epac1 依赖性 p-cPLA2 和 COX-2、p-S6-kinase(T389)和 p-AKT(S473)的增加。此外，在用 COX-2、EP4 或 mTOR 抑制剂预处理细胞后，Epac1 诱导的蛋白质和 DNA 合成也大大减少。用 Epac1 dsRNA、Raptor dsRNA 或 Rictor dsRNA 转染前列腺癌细胞可显著降低 Epac1 依赖性 p-cPLA2 和 COX-2 的增加。
我们表明，作为 cAMP 的下游效应物，Epac1 在前列腺癌细胞中充当促炎调节剂，并通过上调 Ras-MAPK 和 PI-3-kinase-Akt-mTOR 信号来促进细胞增殖和存活。
