Keightley Margaret C, Brown Pamela, Jabbour Henry N, Sales Kurt J
MRC Human Reproductive Sciences Unit, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH164TJ, UK.
BMC Cell Biol. 2010 Jan 21;11:8. doi: 10.1186/1471-2121-11-8.
Prostaglandin (PG) F(2alpha) is a key regulator of endometrial function and exerts its biological action after coupling with its heptahelical G protein-coupled receptor (FP receptor). In endometrial adenocarcinoma the FP receptor expression is elevated. We have shown previously that PGF(2alpha)-FP receptor signalling in endometrial adenocarcinoma cells can upregulate several angiogenic factors including fibroblast growth factor-2 (FGF2). In the present study, we investigated the paracrine effect of conditioned medium produced via PGF(2alpha)-FP receptor signalling in endometrial adenocarcinoma cells stably expressing the FP receptor (Ishikawa FPS cells), on endothelial cell function.
Conditioned medium (CM) was collected from FPS cells after 24 hrs treatment with either vehicle (V CM) or 100 nM PGF(2alpha) (P CM). Treatment of human umbilical vein endothelial cells (HUVECs) with P CM significantly enhanced endothelial cell differentiation (network formation) and proliferation. Using chemical inhibitors of intracellular signalling, we found that P CM-stimulated endothelial cell network formation was mediated by secretion of endothelial PGF(2alpha) and activation of endothelial FP receptors, following FGF2-FGFR1 signalling, phosphorylation of ERK1/2 and induction of COX-2. Whereas, P CM stimulation of endothelial cell proliferation occurred independently of PGF(2alpha) secretion via an FGF2-FGFR1-ERK1/2 dependent mechanism involving activation of the mTOR pathway.
Taken together, we have shown a novel mechanism whereby epithelial prostaglandin F(2alpha)-FP signalling regulates endothelial cell network formation and proliferation. In addition we provide novel in vitro evidence to suggest that prostaglandin F(2alpha) can directly regulate endothelial cell network formation but not endothelial cell proliferation. These findings have relevance for pathologies where the FP receptor is aberrantly expressed, such as endometrial adenocarcinoma, and provide in vitro evidence to suggest that targeting the FP receptor could provide an anti-angiogenic approach to reducing tumour vasculature and growth.
前列腺素（PG）F(2α)是子宫内膜功能的关键调节因子，与七螺旋G蛋白偶联受体（FP受体）结合后发挥其生物学作用。在子宫内膜腺癌中，FP受体表达升高。我们之前已经表明，子宫内膜腺癌细胞中的PGF(2α)-FP受体信号传导可上调包括成纤维细胞生长因子-2（FGF2）在内的多种血管生成因子。在本研究中，我们研究了在稳定表达FP受体的子宫内膜腺癌细胞（Ishikawa FPS细胞）中，通过PGF(2α)-FP受体信号传导产生的条件培养基对内皮细胞功能的旁分泌作用。
用载体（V CM）或100 nM PGF(2α)（P CM）处理24小时后，从FPS细胞中收集条件培养基（CM）。用P CM处理人脐静脉内皮细胞（HUVECs）可显著增强内皮细胞分化（网络形成）和增殖。使用细胞内信号传导的化学抑制剂，我们发现P CM刺激的内皮细胞网络形成是由内皮PGF(2α)的分泌和内皮FP受体的激活介导的，这是在FGF2-FGFR1信号传导、ERK1/2磷酸化和COX-2诱导之后发生的。而P CM对内皮细胞增殖的刺激是通过FGF2-FGFR1-ERK1/2依赖性机制独立于PGF(2α)分泌发生的，该机制涉及mTOR途径的激活。
综上所述，我们展示了一种新机制，即上皮前列腺素F(2α)-FP信号传导调节内皮细胞网络形成和增殖。此外，我们提供了新的体外证据表明前列腺素F(2α)可直接调节内皮细胞网络形成，但不能调节内皮细胞增殖。这些发现与FP受体异常表达的病理学相关，如子宫内膜腺癌，并提供了体外证据表明靶向FP受体可能提供一种抗血管生成方法来减少肿瘤血管生成和生长。
